JP2010004685A - Recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving device for a recording apparatus which can shorten the time required for determining a time-out without requiring special processing unlike a conventional watchdog timer and therefore can determine in a short time whether or not a failure has occurred. <P>SOLUTION: The motor driving device for a recording apparatus includes a timer means for determining whether or not access to registers that must be accessed in driving a motor is made within a preliminarily determined period of time; and a means for determining whether a driving current of a motor is larger or smaller than a preliminarily set current value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a motor driving method in a recording apparatus, and more particularly, to detection / processing at the time of abnormality.

  As a motor of the recording apparatus, a carriage motor that drives a carriage on which the print head is mounted, an ASF motor that feeds / discharges printing paper, an LF motor that feeds printing paper in the sub-scanning direction, and a PG that performs maintenance of the print head There are motors.

  On the other hand, when the CPU for controlling the recording apparatus runs away due to, for example, static electricity, the motor remains in an excited state, causing the motor to fail. In order to remove the cause of the motor failure, when it is determined that the CPU has not been operated for a certain period of time, an interrupt is generated and the CPU is forced to perform an abnormal process to stop the driving of the motor. Are known.

  FIG. 5 is an explanatory diagram of a conventional example.

In this case, in order to determine that the CPU is not operating, the specific timer 54 is accessed (timer clear) within a predetermined time. If there is no timer access for a certain time or more (timeout), a so-called watch dog timer is used that generates an interrupt (see, for example, Patent Document 1).
JP 2004-260971 A

  However, in the watchdog timer system of the conventional example, a significant difference is produced in the abnormality detection ability when the CPU runs away depending on “where the timer access process is performed” in the program process. Accordingly, there is a problem that it takes a lot of time to set the “insertion position” in the timer access process.

  Even when the timer access process is inserted into the motor drive processing unit, the motor drive unit may not be accessed for a certain period of time, such as hold of a stepping motor (weak excitation). In this case, even when the set time is lengthened or the motor is not driven, there is a problem that the processing is complicated because it is necessary to perform timer access.

The present invention eliminates the need for special processing as in the conventional watchdog timer, and can shorten the time until time-out determination, and can determine the occurrence of an abnormality in a short time. The purpose is to provide.

The present invention relates to timer means for determining whether or not access to a register that must be accessed during motor driving has not been performed within a predetermined time, and a motor driving current set in advance. Means for determining the magnitude of the value.

According to the present invention, the timer can be cleared without requiring any special processing and at the drive control timing of the motor, so the time until the time-out determination can be shortened, and the occurrence of an abnormality can be determined in a short time. There is an effect that can be done.

  The best mode for carrying out the invention is the following embodiment.

  FIG. 1 is a diagram illustrating a motor driving device 100 in a recording apparatus PR1 that is Embodiment 1 of the present invention.

  The recording apparatus PR1 includes a motor driving device 100, a carriage 30, an operation panel 31, a carriage motor M1, an LF motor M2, a PG motor M3, and an ASF motor M4.

  The carriage motor M1 drives the carriage 30 on which the print head is mounted. The LF motor M2 performs sub-scanning of the recording paper. The PG motor M3 performs head maintenance. The ASF motor M4 feeds / discharges the recording paper.

  The motor driving device 100 includes an ASIC 10, a ROM 16, a DRAM 19, and motor drivers MD1, MD2, MD3, and MD4.

  The ASIC 10 includes a CPU 12, a RAM 13, a DMA 14, a USB 15, a DRAM control unit 18, a head control unit 20, a panel control unit 21, and motor control units MC1, MC2, MC3, and MC4.

  The motors M1, M2, M3, and M4 are driven by motor drivers MD1, MD2, MD3, and MD4, respectively. The motor drivers MD1, MD2, MD3, and MD4 are controlled by motor control units MC1, MC2, MC3, and MC4 in a large-scale integrated circuit (ASIC 10) that controls the entire printing apparatus PR1.

  The CPU 12 is an example of means for detecting register access related to motor driving.

  FIG. 2 is a diagram illustrating a motor control unit MC1 that is a main part of the recording apparatus PR1.

  The motor control unit MC1 includes a current value setting register 1, a lower limit value setting register 2, a comparison circuit 3, a timer 4, a timeout detection unit 5, and an AND circuit 6.

  The current value setting register 1 for setting the motor driving current value is written from the CPU by the LOAD0 signal. The lower limit value setting register 2 for setting the lower limit value of the motor driving current value is written by the LOAD1 signal, and the comparison circuit 3 has a value larger than the value of the lower limit value setting register 2 in the current value setting register 1. When set, it is true (1).

  The lower limit value setting register 2 is set to a value slightly larger than the weak excitation current in the motor holding state.

  The timer 4 that counts up at regular intervals is cleared when the current value setting register 1 is written. When the value of the timer 4 exceeds a preset value, the timeout detection unit 5 becomes true (1). That is, if the current value setting register 1 is not written for a certain time or longer, the result is true (1).

  The current value setting register 1 is an example of a current value setting register that sets a motor driving current value.

  The lower limit value setting register 2 is an example of a lower limit value setting register that sets the lower limit value of the motor drive current.

  The comparison circuit 3 is an example of comparison means for comparing the value of the current value setting register with the value of the lower limit value setting register.

  The timer 4 is an example of a timer that detects a register access interval to the motor drive unit.

  The AND circuit 6 generates an interrupt that generates an interrupt to the CPU when it is determined that the value of the current value setting register exceeds the value of the lower limit value setting register and the timer value exceeds a preset time interval. It is an example of a means.

  When the value of the current value setting register exceeds the value of the lower limit value setting register and the value of the timer exceeds a preset time interval, the CPU 12 sets the value of the current value setting register to a predetermined current. It is an example of the setting means set to a value.

  FIG. 3 is a diagram for explaining current setting values during printing in the carriage motor M1, the LF motor M2, the PG motor M3, and the ASF motor M4.

  Since the carriage motor M1 is driven to perform main scanning on the carriage on which the head is mounted, the setting value is large, and the LF motor M2 holds the recording paper during the carriage main scanning period. The setting value of low current (weak excitation). Therefore, the PG motor M3 and the ASF motor M4 are set to excitation off (zero current) without being excited.

  When the main scanning of the carriage is completed, a large current is set in the LF motor M2 to drive the LF motor M2 to sub-scan the recording paper, and the other motors are turned off (zero current). Set.

  FIG. 4 is a diagram comparing the output during printing in the carriage motor M1, the LF motor M2, the PG motor M3, and the ASF motor M4.

  It can be seen that the carriage motor M1 and the LF motor M2 are true (1) only when a large current is set to drive the carriage motor M1 and the LF motor M2.

  Next, the operation of the above embodiment will be described in detail.

  During the printing operation, the carriage motor M1 changes the current value so that the carriage moving speed becomes constant at certain time intervals (for example, 10 msec) by servo control. That is, since the current value setting register 1 for the carriage motor M1 is written every 10 msec, the timer 4 for the carriage motor M1 is cleared each time.

  The lower limit setting register 2 for the carriage motor M1 is set in advance (for example, a value corresponding to 0.3A is set) at the time of initialization immediately after the recording apparatus PR1 is turned on, and the timeout detection unit 5 is also the same. For example, 1 sec is set.

  When the printing operation is normally performed, the timer 4 is cleared every 10 msec as described above, so that no timeout occurs.

  On the other hand, the LF motor M2 holds the recording paper by weak excitation. However, since the current setting value for the LF motor M2 at this time is a current that does not exceed the lower limit value for the LF motor M2, the output of the comparison circuit 3 is false (0).

  At the time of sub-scanning driving after the main scanning driving of the carriage motor M1 is completed, the output of the comparison circuit 3 for the carriage motor M1 becomes false (0), which is opposite to that at the time of main scanning, for the LF motor M2. The output of the comparison circuit 3 becomes true (1).

  However, if the CPU goes out of control for some reason, such as noise, normal servo control cannot be executed, so writing to the current value setting register 1 is not performed. If this state continues for 1 second or more, a timeout occurs and a timeout is detected. The unit 5 outputs true (1). If the set current value is larger than the set value of the lower limit setting register 2, the output of the comparison circuit 3 becomes true (1).

  That is, an interrupt output is generated only when “a large set current state (output of the comparison circuit 3 is true (1))” and “timeout state (output of the timeout detection unit 5 is true (1))”. Let Further, the value of the current value setting register 1 is set to a predetermined value (for example, 0 A).

  Therefore, in a state where the “current set value” is smaller than the “current lower limit value”, even if a timeout occurs, an abnormal state due to an interrupt process or the like does not occur.

  In other words, if the current is low and the current value does not cause a failure even if an abnormality occurs, there is no problem even if a timeout occurs, so useless register access (timer access) to prevent timeout. There is no need to do. Therefore, software processing can be simplified, and an abnormality can be reliably processed by an interrupt or the like when the current is large.

  In general, when driving a motor, if the current setting value is large, it is necessary to always perform processing such as phase switching or current control at regular intervals, so the current value setting register 1 is updated (accessed). If it is not done, there is a high possibility that it is abnormal, and there is a high possibility that it will cause a failure.

  If the motor to be used is a stepping motor, the lower limit value of the current may be set to a set value corresponding to a value higher than the current value in the weakly excited state such as during holding.

In the case of a DC motor, it may be set to a value corresponding to a current value that does not cause a problem such as a temperature rise in the rotating shaft in the hold state.

1 is a diagram illustrating a motor driving device 100 in a recording apparatus PR1 that is Embodiment 1 of the present invention. FIG. It is a figure explaining motor control part MC1 which is the principal part of recording device PR1. It is a figure explaining the electric current setting value at the time of printing in the carriage motor M1, LF motor M2, PG motor M3, and ASF motor M4. It is the figure which compared the output at the time of printing in the carriage motor M1, LF motor M2, PG motor M3, and ASF motor M4. It is explanatory drawing of a prior art example.

Explanation of symbols

100: Motor drive device,
PR1 ... Recording device,
10 ... ASIC,
1 ... Current value setting register,
2 ... Lower limit setting register,
3 ... Comparison circuit,
4 ... Timer,
5 ... timeout detection unit,
6 ... AND circuit,
30 ... carriage,
31: Operation panel.

Claims (4)

In the motor drive device of the recording device,
Means for detecting register access for motor drive;
A current value setting register for setting the motor drive current value;
A lower limit value setting register for setting the lower limit value of the motor drive current;
Comparing means for comparing the value of the current value setting register with the value of the lower limit value setting register;
A timer for detecting a register access interval to the motor drive unit;
An interrupt generating means for generating an interrupt to the CPU when it is determined that the value of the current value setting register exceeds the value of the lower limit value setting register and the value of the timer exceeds a preset time interval;
A motor drive device for a recording apparatus, comprising: In the motor drive device of the recording device,
Means for detecting register access for motor drive;
A current value setting register for setting the motor drive current value;
A lower limit value setting register for setting the lower limit value of the motor drive current;
A comparison means for comparing the value of the current value setting register with the value of the lower limit value setting register;
A timer for detecting a register access interval to the motor drive unit;
When the current value setting register value exceeds the lower limit value setting register value and the timer value exceeds a preset time interval, the current value setting register value is set to a predetermined current value. Setting means to do;
A motor drive device for a recording apparatus, comprising: In the control method of the motor drive device of the recording apparatus,
Detecting register access for motor drive;
A step of setting a motor drive current value by a current value setting register;
A step in which the lower limit setting register sets the lower limit of the motor drive current;
A comparison step of comparing the value of the current value setting register with the value of the lower limit value setting register;
A timer detecting a register access interval to the motor driver;
An interrupt generation step of generating an interrupt to the CPU when it is determined that the value of the current value setting register exceeds the value of the lower limit value setting register and the value of the timer exceeds a preset time interval;
A method for controlling a motor driving device of a recording apparatus. In the control method of the motor drive device of the recording apparatus,
Detecting register access for motor drive;
A step of setting a motor drive current value by a current value setting register;
A step in which the lower limit setting register sets the lower limit of the motor drive current;
A comparison step of comparing the value of the current value setting register with the value of the lower limit value setting register;
A timer detecting a register access interval to the motor driver;
When the current value setting register value exceeds the lower limit value setting register value and the timer value exceeds a preset time interval, the current value setting register value is set to a predetermined current value. A setting process to perform;
A method for controlling a motor driving device of a recording apparatus.

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