JPH05278279A - Printer - Google Patents

Abstract

PURPOSE:To effectively use a timer interrupt signal by a method wherein a driving circuit is constructed at a low cost by controlling by driving a plurality of stepping motors by one timer interrupt signal. CONSTITUTION:A timer which outputs a timer interrupt signal, an acceleration deceleration control table which stores an acceleration deceleration pattern of a stepping motor as a number of steps and a number of inter rupts, a first interrupt counter and a second interrupt counter which count the number of interrupts of the time interrupt signal after processing by shifting respectively to the first stepping motor and the second stepping motor, and a first step counter and a second step counter which count a number of steps, are provided. Then, every time shift processing of a control signal of the stepping motor is carried out, (1) is added to a counted value of a corresponding step counter in accelerating and (1) is subtracted therefrom in decelerating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer provided with a plurality of stepping motors.

[0002]

2. Description of the Related Art A printer using a stepping motor to convey a sheet is known. By rotating the stepping motor, the platen, rollers and the like are rotated, and the paper is conveyed from the storage section to the print head and the like.

For example, in a printer provided with a plurality of print heads such as a color printer, a stepping motor is provided corresponding to each print head (platen) in order to convey a sheet in response to a printing operation by each print head. It was provided.

However, although the stepping motor is driven and controlled by a pulse signal, it may not be driven because it cannot follow even if a pulse signal corresponding to a desired speed is input at the start of driving, which is called slow-up at the start of driving. I had to do accelerated processing. That is, it is necessary to drive and control a plurality of stepping motors at different timings.

Therefore, in the conventional color printer, in order to drive and control a plurality of stepping motors,
A separate CPU (central
proc-essing unit) was installed and each stepping motor was independently driven and controlled. Some CPUs have a plurality of timer interrupt signal input terminals (three of which are known). Therefore, a stepping motor is provided for each timer interrupt signal input terminal. Then, the stepping motors having the number of input terminals of the timer interrupt signal are independently driven and controlled by the software processing by the timer interrupt.

[0006]

In a conventional printer in which a plurality of CPUs are provided for a plurality of stepping motors and the stepping motors are independently driven and controlled, the circuit configuration becomes complicated and the cost increases. There was a problem.

Further, in the case where the stepping motors having the number of input terminals of the timer interrupt signal are independently driven and controlled by the software processing by the timer interrupt, the software processing becomes large, so that the software processing is developed. There is a problem that it takes time and cost. Furthermore C
The PU timer interrupt signal input terminal inputs, for example, a timer interrupt signal to a peripheral device, and the CPU must process the timer interrupt signal. Therefore, the timer interrupt signal for controlling the driving of the stepping motor is input. There is a problem in that the use of the input signal input terminal is limited in quantity.

Therefore, the present invention provides a printer which can drive and control a plurality of stepping motors by one timer interrupt signal, and thus can inexpensively configure a drive circuit for the stepping motor and effectively use the timer interrupt signal. With the goal.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a plurality of stepping motors, each of which is driven in one step by one pulse input of a control signal, is provided, and a printing operation is performed by driving each of the stepping motors. Timer interrupt means for outputting an interrupt signal, a plurality of drive timing output means provided corresponding to each stepping motor, and respectively outputting the drive timing of the corresponding stepping motor, and corresponding to each drive timing output means A plurality of interrupt number counters, each of which is provided to start counting the number of output of the interrupt signal when the drive timing is output by the corresponding drive timing output means,
A pulse cycle storage means that stores a plurality of pulse cycles that change stepwise during acceleration / deceleration in the control signal in association with the number of times the interrupt signal is output, and is provided corresponding to each stepping motor and controls the corresponding stepping motor. Pulse cycle designating means for designating the pulse cycle of the control signal, and the output frequency of the interrupt signal stored in the pulse cycle storing means corresponding to the pulse cycle designated by the pulse cycle designating means. When the counter counts, the control signal output means for initializing the count value and starting the re-counting for this interrupt counter and outputting one pulse of the control signal, and one pulse output by this control signal output means. When accelerating or decelerating, the pulse cycle specified by the pulse cycle specifying means is one step shorter or one step. Those provided had a pulse period changing means for changing the pulse period.

[0010]

In the present invention having such a structure, when the drive timing is output by the drive timing output means, the count of the number of outputs of the interrupt signal output by the timer interrupt means is counted by the interrupt number counter. Be started.

When the corresponding interrupt frequency counter counts the output frequency of the interrupt signal stored in the pulse cycle storage means in accordance with the pulse cycle specified by the pulse cycle specifying means, the control signal output means The count value of the interrupt counter is initialized and recounting is started, and one pulse of the control signal is output to the corresponding stepping motor.

When one pulse of the control signal is output, the pulse cycle changing means changes the pulse cycle specified by the pulse cycle specifying means by one step shorter or one step longer during acceleration or deceleration, respectively. Is changed to.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a printer provided with two thermal heads using an ink ribbon, and in FIG.
It is a PU (central processing unit). This CPU
ROM storing the program data of the processing performed by 1.
(Read only memory) 2 and RAM in which various memory areas used when the CPU 1 performs processing are formed
The (random access memory) 3 is connected to the CPU 1 via the system bus 4.

A first printing unit 5 including a first thermal head 5a, a first ribbon motor 5b, and a first stepping motor 5c, a second thermal head 6a, a second ribbon motor 6b, and a second stepping device. The second printing unit 6 including the motor 6c further includes a first drive timing output unit that detects a sheet and outputs a drive timing signal to the first stepping motor and the second stepping motor. The feed sensor 5d and the second feed sensor 6d are provided.

A head driver 7 for driving the first thermal head 5a and the second thermal head 6a, a stepping motor driver 8 for driving the first stepping motor 5c and the second stepping motor 6c, and a second A ribbon motor driver 9 for driving the first ribbon motor 5b and the second ribbon motor 6b is connected to the CPU 1 via the system bus 4.

I / I for inputting output signals from the first feed sensor 5d and the second feed sensor 6d
A keyboard controller 1 for controlling an O (input / output) port 10 and a keyboard 11 for inputting various data
2. A display controller 14 for controlling a display 13 for displaying various data, and a buzzer controller 1 for controlling a buzzer 15 for leaving an alarm when an error occurs.
6. The communication interface 17 connected to the host computer via the line is also connected to the CPU 1 via the system bus 4.

Further, the CPU 1 is provided with a predetermined time interval t.
A timer 18 as a timer interrupt means for outputting a timer interrupt signal every time is connected.

As shown in FIG. 2 (a), the RAM 3 is provided with an acceleration / deceleration control table 3a as a pulse cycle storing means for storing the number of interrupts corresponding to the number of steps, and FIG. As shown in b), the first (1-) interrupt counter 3b1 and the second (2-) interrupt counter 3b2 as the interrupt number counter and the first step counter 3b3 as the pulse cycle designating means, A counter area 3b provided with a second step counter 3b4 is formed, and a flag area 3c provided with a first flag and a second flag and a first state flag and a second state flag is formed. Has been done.

Further, in the first printing unit 5 and the second printing unit 6, as shown in FIG. 3, the first printing unit 5 and the second printing unit 6 are arranged so as to face the first thermal head 5a and the second thermal head 6a. A platen 5e and a second platen 6e are provided for the first thermal head 5a and the first thermal head 5a.
Between the platen 5e and the second thermal head 6
A conveyance path is provided so that the sheet is conveyed between a and the second platen 6e. Then, the first feed sensor 5d and the second feed sensor 6d are
The first thermal head 5a and the second thermal head 6a are provided on the transport path at positions separated by a set distance in the transport source direction. A first ink ribbon cassette 5f and a second ink ribbon cassette 6f for supplying ink ribbons are detachably provided on the printing surfaces of the first thermal head 5a and the second thermal head 6a.

The first stepping motor 5c and the second stepping motor 6c are connected to the first platen 5e and the second platen 6e via a belt, and the rotation of the stepping motors 5c and 6c is performed. The platens 5e and 6e are rotationally driven by driving. Further, the first platen 5
e and the second platen 6e are connected to a first feed roller 5h and a second feed roller 6h via a first gear 5g and a second gear 6g, respectively. According to the rotational drive of the second platen 6e, the first feed roller 5h and the second feed roller 5h
The feed roller 6h rotates to convey the paper.

FIG. 4 shows the flow of the timer interrupt process performed by the CPU 1 when the timer 18 outputs a timer interrupt signal.

First, it is determined whether or not the sheet is detected by the first feed sensor 5d. If no paper is detected by the first feed sensor 5d, RA
It is determined whether the first flag formed in M3 is 0. If this first flag is 0, then step 1 (ST
As the processing of 1), it is determined whether or not a sheet is detected by the second feed sensor 6d, and if the first flag is not 0, the first step counter formed in the RAM 3 is formed. It is determined whether or not the count value of 3b3 is 0. If the count value of the first step counter 3b3 is 0, the first flag is set to 0 and the processing of the above step 1 is performed, and if the count value of the first step counter 3b3 is 0. If not, the first stepping motor control process described below is performed. When the first stepping motor control process is completed, the process of step 1 described above is performed.

If a sheet is detected by the first feed sensor 5d, the first flag is set to 1 and the first stepping motor control process described later is performed. When the first stepping motor control process is completed, the process of step 1 described above is performed.

In the processing of step 1, it is judged whether or not the sheet is detected by the second feed sensor 6d. If the sheet is not detected by the second feed sensor 6d, the second sheet formed in the RAM 3 is detected. It is determined whether the flag is 0. If the second flag is 0, the timer interrupt process is terminated. If the second flag is not 0, the count value of the second step counter 3b4 formed in the RAM 3 is 0. Judge whether or not. Second
If the count value of the step counter 3b4 is 0, the second flag is set to 0 and the timer interrupt process is terminated.
If the count value of is not 0, the second stepping motor control process described later is performed. When the second stepping motor control process ends, the timer interrupt process ends.

If a sheet is detected by the second feed sensor 6d, the second flag is set to 1 and a second stepping motor control process described later is performed. When the second stepping motor control process ends, the timer interrupt process ends.

FIG. 5 shows the flow of the above-mentioned first stepping motor control processing.

First, it is determined whether the first status flag formed in the RAM 3 is 0 or 1.

If the first state flag is 0, the first interrupt counter 3b1 formed in the RAM 3 is incremented by +1.

The count value of the first interrupt counter 3b1 on which this addition processing has been performed is stored in correspondence with the number of steps designated by the count value of the first step counter 3b3 in the acceleration / deceleration control table 3a. Check if it is equal to the number of interrupts. When the count value of the first interrupt counter 3b1 is equal to the number of interrupts stored in the acceleration / deceleration control table 3a, the first stepping motor 5
In the control signal output to c, a motor shift for changing the high level to the low level or changing the low level to the high level is performed (control signal output means), and +1 addition processing is performed to the first step counter 3b3 (pulse). (Cycle changing means), and 0 is set in the first interrupt counter (control signal output means).

Next, it is confirmed whether the count value of the first step counter 3b3 is 5, and the first step counter 3b is checked.
When the count value of 3 is 5, the first state flag is set to 1
To set.

Then, the first stepping motor control process is ended.

If the first status flag is 1, the first
+1 is added to the interrupt counter 3b1.

The count value of the first interrupt counter 3b1 on which this addition processing has been performed is stored in correspondence with the number of steps designated by the count value of the first step counter 3b3 in the acceleration / deceleration control table 3a. Check if it is equal to the number of interrupts. When the count value of the first interrupt counter 3b1 is equal to the number of interrupts stored in the acceleration / deceleration control table 3a, the motor is shifted and 0 is set in the first interrupt counter 3b1 (control signal output means). ).

Next, it is confirmed whether or not the printing is completed. When the printing is completed, the first status flag is set to 2 and the first interrupt counter 3b1 is set to 0.

Then, the first stepping motor control process is ended.

If the first state flag is neither 0 nor 1, that is, the first state flag is 2, it is determined that the first interrupt counter 3b1 is incremented by +1.

The count value of the first interrupt counter 3b1 on which this addition processing has been performed is stored in correspondence with the number of steps designated by the count value of the first step counter 3b3 in the acceleration / deceleration control table 3a. Judge whether it is equal to the number of interrupts. If the count value of the first interrupt counter 3b1 is not equal to the number of interrupts stored in the acceleration / deceleration control table 3a, the first stepping motor control process is ended.

If the count value of the first interrupt counter 3b1 is equal to the number of interrupts stored in the acceleration / deceleration control table 3a, the motor is shifted (control signal output means) and the first step counter 3b3. −1 is subtracted (pulse cycle changing means), and 0 is set in the first interrupt counter 3b1 (control signal output means).

Next, it is confirmed whether or not the count value of the first step counter 3b3 is 0, and the first step counter 3
When the count value of b3 is 0, 0 is set in the first state flag.

Then, the first stepping motor control process is ended.

FIG. 6 shows the flow of the above-mentioned second stepping motor control processing.

Basically, this second stepping motor control process is also almost the same as the above-mentioned first stepping motor control process, except that the second state flag, the second interrupt counter 3b2, The only difference is that the second step counter 3b4 is used. Therefore, the description of the flow of the second stepping motor control process is omitted here.

In this embodiment having such a structure, the timer interrupt signal from the timer 18 shown in FIGS.
Shift processing of the first stepping motor 5c, shift processing of the second stepping motor 6c, control signal of the first stepping motor 5c, second stepping motor 6
a control signal of c, a detection signal of the first feed sensor 5d,
As in the example of the timing of the detection signal of the second feed sensor 6d, the first stepping motor 5c and the second stepping motor 6c are acceleration / deceleration controlled by the timer interrupt signal from the timer 18.

First, as shown in FIG. 7, when the first feed sensor 5d detects a sheet (time A), the first status flag is set to 0 at that time, so the timer interrupt signal immediately after that is set. At (B time), acceleration drive is started for the first stepping motor 5c.

That is, in acceleration driving, when the timer interrupt signal is input (time B), the number of interrupts is set when the first step counter 3b3 is 0 (step number 0) by the acceleration / deceleration control table 3a. Is set to 1,
Since the number of times the timer interrupt signal has been input, that is, the count value of the first interrupt counter 3b1 (the number of interrupts) is 1, the first stepping motor 5c is subjected to the shift processing, and the first stepping motor 5c is shifted. The control signal of the stepping motor 5c changes from low level to high level. Then, the count value of the first step counter 3b3 becomes 1.

According to the acceleration / deceleration control table 3a, when the first step counter 3b3 is 1 (step number 1), the number of interrupts is set to 5, and the number of input of the timer interrupt signal after the shift process, that is, the first Interrupt counter 3b1
The control signal of the first stepping motor 5c is maintained at the high level until the count value (interruption count) of 5 becomes 5. The count value of the first interrupt counter 3b1 is 5
Then, the shift process is performed again on the first stepping motor 5c, and the first stepping motor 5c
Control signal changes to low level. Then, the count value of the first step counter 3b3 becomes 2.

In this way, based on the acceleration / deceleration control table 3a, the number of interruptions of the timer interruption signal after the shift processing,
That is, the first interrupt counter 3b1 causes 4, 3,
When 2 is counted, the shift process is performed on the first stepping motor 5c each time, and the control signal of the first stepping motor 5c changes to high level, low level, or high level. Then, the count values of the first step counter 3b3 become 3, 4, and 5 in order.

When the first step counter 3b3 reaches 5, the first state flag is set to 1, and the next timer interrupt signal (at time C) causes the first stepping motor 5 to move.
Constant speed drive is performed on c.

That is, in the constant speed drive, the number of interrupts is set to 1 corresponding to the number of steps 5 in the acceleration / deceleration control table 3a, so that the first stepping is performed each time the timer interrupt signal is input. The control signal of the motor 5c changes from low level to high level or from high level to low level.

Next, as shown in FIG. 8, when the sheet is detected by the second feed sensor 6d (at the time point D), the second state flag at that time is set to 0, so that immediately after that. By the timer interrupt signal (at the time point E), the acceleration driving is started for the second stepping motor 6c, similarly to the control of the first stepping motor 5c.

That is, when the second interrupt counter 3b2 sequentially counts 1, 5, 4, 3 and 2, the shift process is performed on the second stepping motor 6c every time the second interrupt counter 3b2 counts. The control signal of the stepping motor changes from high level, low level, high level, low level, and high level. And the second step counter 3b4
Count values of 0 are sequentially 1, 0, 2, 3, 4, 5.

When the second step counter 3b4 reaches 5, the second state flag is set to 1, and the next timer interrupt signal (time F) causes the same operation as the control of the first stepping motor 5c. , Second stepping motor 6c
Is driven at a constant speed.

As shown in FIG. 9, after the first feed sensor 5d detects the end of the paper (at time G), when the first printing unit 5 finishes printing on the paper, the first status flag is Set to 2 and the next timer interrupt signal (at the time of H)
As a result, deceleration driving is started for the first stepping motor 5c.

That is, in the deceleration driving, contrary to the acceleration driving, 1, 2, 3,
When 4 and 5 are counted, shift processing is performed on the first stepping motor 5c, and the control signal of the first stepping motor 5c changes to low level, high level, low level, high level, low level. Change. Then, the count value of the first step counter 3b3 is 4,
It becomes 3, 2, 1, 0.

When the count value of the first step counter 3b3 becomes 0, the first state flag is set to 0, and the control process of the first stepping motor 5c is performed next by the first feed sensor 5d. Will not be performed until is detected.

Next, as shown in FIG. 10, after the second feed sensor 6d detects the end of the sheet (time i), the second
When the printing unit 6 finishes printing on the paper, the second status flag is set to 2, and the next timer interrupt signal (J
At the time point), similarly to the control of the first stepping motor 5c, the deceleration drive is started for the second stepping motor 6c.

By this deceleration driving, when the second step counter 3b4 becomes 0, the second state flag is set to 0, and the control process of the second stepping motor 6c is next performed by the second feed sensor 6d. It will not be performed until the paper is detected.

As described above, according to this embodiment, as the acceleration / deceleration pattern of the stepping motor, the acceleration / deceleration control table 3a storing the number of interrupts corresponding to the number of steps is provided, and the first stepping motor 5c and the second stepping motor 5c are provided. Corresponding to the stepping motor 6c, the first interrupt counter 3b1 and the second interrupt counter 3b2 for counting the number of input of the timer interrupt signal after the shift processing, and the first interrupt counter 3b2 for counting the number of steps respectively. Step counter 3b
3 and the second step counter 3b4 are provided, the first timer interrupt signal from the timer 18 causes the first
The stepping motor 5c and the second stepping motor 6c can be independently accelerated / decelerated.

Therefore, in the drive circuit of each stepping motor, it is not necessary to provide a CPU for each stepping motor, and it is not necessary to provide an interrupt signal corresponding to each stepping motor, which is inexpensive and simple. The drive circuit can drive and control the stepping motor.

Further, since only one timer interrupt signal is required, one of the two timer interrupt signals for controlling the stepping motor in the conventional printer control circuit is
Can be used for other purposes. That is, the timer interrupt signal can be effectively used.

In this embodiment, the printer provided with two stepping motors has been described, but the present invention is not limited to this, and the printer provided with three or more stepping motors. Also applies to.

[0062]

As described in detail above, according to the present invention,
It is possible to provide a printer in which a plurality of stepping motors can be driven and controlled by one timer interrupt signal, and thus a driving circuit for the stepping motor can be inexpensively configured and the timer interrupt signal can be effectively used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of essential parts of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an acceleration / deceleration control table and a counter area of the embodiment.

FIG. 3 is a diagram showing a schematic configuration of a first printing unit and a second printing unit of the same embodiment.

FIG. 4 is a diagram showing a flow of timer interrupt processing of the embodiment.

FIG. 5 is a diagram showing a flow of a first stepping motor control process of the embodiment.

FIG. 6 is a diagram showing a flow of a second stepping motor control process of the embodiment.

FIG. 7 is a diagram showing timings of various signals in the embodiment.

FIG. 8 is a diagram showing timings of various signals in the embodiment.

FIG. 9 is a diagram showing timings of various signals in the embodiment.

FIG. 10 is a diagram showing timings of various signals in the embodiment.

[Explanation of symbols]

1 ... CPU, 3a ... Acceleration / deceleration control table, 3b1 ... 1st
Interrupt counter, 3b2 ... second interrupt counter, 3b3
... first step counter, 3b4 ... second step counter, 5c ... first stepping motor, 5d ... first
Feed sensor, 6c ... second stepping motor,
6d ... 2nd feed sensor, 18 ... Timer.

Claims (1)

[Claims] 1. A plurality of stepping motors, each of which is driven in one step by inputting one pulse of a control signal,
In a printer that performs a printing operation by driving each of the stepping motors, a timer interrupt means that outputs an interrupt signal at a constant time interval, and a stepping motor that is provided corresponding to each of the stepping motors are provided. A plurality of drive timing output means for outputting and a plurality of drive timing output means provided corresponding to each of the drive timing output means, and for starting the counting of the number of output of the interrupt signal when the drive timing is output by the corresponding drive timing output means. An interrupt counter, a pulse cycle storage unit that stores a plurality of pulse cycles that change stepwise during acceleration / deceleration in the control signal in association with the number of times the interrupt signal is output, and corresponds to each stepping motor. Provide the pulse cycle of the control signal that controls the corresponding stepping motor. When the interrupt cycle counter corresponding to the pulse cycle designating means and the output frequency of the interrupt signal stored in the pulse cycle storing means corresponding to the pulse cycle designated by the pulse cycle designating means is counted, A control signal output means for initializing a count value to the frequency counter and starting re-counting, and for outputting one pulse of the control signal, and one pulse output by the control signal output means, the control signal output means is used during acceleration or deceleration. A printer provided with pulse cycle changing means for changing the pulse cycle designated by the pulse cycle designating means to a pulse cycle shorter by one step or a pulse cycle longer by one step.