JPH0970199A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the current consumption of a step motor and, at the same time, to suppress the heat generation of the motor itself in a printer, such as the serial printer, etc., which performs printing operations by moving a carriage mounted with a printing head back-and-forth by means of a step motor. SOLUTION: A printer moves a carriage mounted with a printed head H by sliding along a platen by exciting and driving a the driving motor Mc of the carriage by using a one/two phase exciting system. In the case where the motor Mc is in a two-phase excited state when the carriage is moved to the printing starting end at which the carriage is detected by means of a position sensor 18, the motor Mc is stopped and maintained in a one-phase excited state by exciting and driving the motor Mc by one step. The normally rotating amount of the motor Mc until the carriage completes one-line printing from the printing starting end and the reversely rotating amount of the motor Mc until the carriage is moved to the printing starting end after completing the one-line printing are determined from even numbers of exciting steps and, when the motor Mc is temporarily stopped in association with turning back the carriage, the motor is always stopped and maintained in the one-phase excited state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus such as a serial printer which prints by reciprocating a carriage having a print head by using a step motor.

[0002]

2. Description of the Related Art In a serial printer built in a word processor, for example, a step motor is used as a carriage driving motor for moving a carriage having a print head mounted thereon along a platen.

This step motor is rotationally driven by sequentially exciting a plurality of excitation phases in the rotation direction, and has, for example, four excitation phases (A phase, B phase, C phase, D phase). As an excitation method for driving the step motor, each excitation phase is A phase → AB phase → B phase → BC phase → C phase → C.
The 1-2 phase excitation method in which the 1 phase excitation and the 2 phase excitation are sequentially switched and excited as D phase → D phase → DA phase → ... is widely adopted as an excitation method suitable for obtaining high torque at high rotation. ing.

[0004]

[Problems to be Solved by the Invention] However, 1-2
When the step motor is driven by the phase excitation method, the consumption current in the two-phase excitation is naturally double the consumption current in the one-phase excitation, but it may cause a temporary stop of the carriage during printing. Accordingly, if the step motor is held in a two-phase excitation state, not only the current consumption as a printer increases but also the temperature rise of the motor increases.

Further, when the step motor is held at a certain stop position, the level of the one-phase or two-phase excitation phase corresponding to the stop position is the same level as that at the time of rotational driving or slightly lower than that. Since a current and a voltage have to be continuously applied, there is a problem that the heat generation of the motor is remarkable.

That is, in the conventional serial printer built in the word processor, there is a problem that the stepper motor for moving the carriage on which the print head is mounted consumes a large amount of current and generates a great deal of heat.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a printing apparatus capable of reducing current consumption in a step motor and suppressing heat generation of the motor itself. And

[0008]

That is, a printer according to claim 1 of the present invention comprises a step motor for reciprocally moving a carriage having a print head in the width direction of a recording sheet, and a step motor 1-2. A motor drive means for driving by phase excitation; a detection means for detecting the excitation state of the step motor by the motor drive means; and a stop means for stopping the drive of the step motor to stop the carriage during printing. When the excited state detected by the detecting means is the one-phase excited state, the excited state is maintained, and when the excited state detected by the detecting means is the two-phase excited state, the excited state is held after the change to the one-phase excited state. Then, a control means for stopping the step motor is provided.

That is, in the printing apparatus according to the first aspect, when the driving of the step motor by the 1-2 phase excitation is stopped in order to stop the carriage during printing, the step motor detected by the detection means is detected. When the excitation state of 1 is one-phase excitation, the one-phase excitation state is maintained, and when the excitation state of the step motor detected by the detection means is two-phase excitation, the one-phase excitation is waited until it changes to one-phase excitation. Since the step motor is stopped and controlled so that the excited state is maintained, the current consumption of the motor is reduced and the temperature rise is also reduced.

A printer according to claim 2 of the present invention is the printer according to claim 1, further comprising:
Position detection means for detecting the position of the carriage at a predetermined position of the movement path of the carriage, and one-phase excitation of the step motor by the motor drive means based on information from the position detection means at the start of printing. A start position determining means for determining the position of the carriage being set as the start position of the moving range of the carriage, and during printing,
A second control for controlling the motor driving means to move the carriage within a range from the start end position to the end position of the carriage where the carriage is moved by a predetermined even number of steps of the step motor. And means.

That is, the printing apparatus according to claim 2 is the printing apparatus according to claim 1, further comprising:
When the carriage is moved from the start end position of the movement range of the carriage in which the step motor is excited by one phase, the movement within the range to the carriage end position is controlled by a predetermined even number of steps. At the carriage movement start end position and the movement turnaround position during printing, the step motor is always stopped at the one-phase excitation position, so that it is possible to reduce current consumption and heat generation.

A printer according to claim 3 of the present invention is the printer according to claim 1 or 2, wherein the step motor is excited when the carriage is moving forward and backward. An exciting current changing means for changing the current value is provided.

That is, in the printing apparatus according to the third aspect, in the printing apparatus according to the first or second aspect, further, the exciting current value of the step motor during movement of the forward path and the backward path of the carriage. Is changed, the total current consumption of the motor is reduced by lowering the excitation current during the backward movement, which simply returns to the movement start position, compared to the forward movement of the carriage where actual printing is performed. Heat generation will also be suppressed.

Further, according to a fourth aspect of the present invention, in a printing apparatus, a step motor for reciprocating a carriage having a print head in the width direction of a recording sheet and a motor for driving the step motor by 1-2 phase excitation. A driving means; and a control means for stopping the excitation by the motor driving means and applying a pulse train to one phase of the step motor when stopping the step motor to stop the carriage during printing. Is characterized by.

That is, in the printing apparatus according to the fourth aspect, when the driving of the step motor by the 1-2 phase excitation is stopped in order to stop the carriage during printing, the excitation is stopped and the first phase is changed to the first phase. Since the pulse train is applied and the stop position is maintained, heat generation of the motor is suppressed as compared with the case where the exciting current is continuously applied.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an electronic circuit of a word processor equipped with the printing apparatus of the present invention.

This word processor includes a control unit (CP
U) 11. This control unit (CPU) 11 is
Based on the key operation signal supplied from the key input unit 12,
A system program stored in advance in the ROM 13 is activated to control the operation of each section of the circuit. The control section (CPU) 11 includes the key input section 12, RO
In addition to M13, the RAM 14 and the liquid crystal display unit 19 are connected.

A thermal print head H is connected to the control unit (CPU) 11 from the print control unit 15 via a head driver 16a, and a carriage drive motor (step motor) via a carriage motor driver 16b. Mc is connected, and the paper feed motor driver 16
A paper feed motor Mp is connected via c.

Further, the control unit (CPU) 11 includes
A carriage position detection sensor 18 is connected via the detection circuit 17. In the key input unit 12, kana character keys for inputting an arbitrary character string (document) to be printed data, numeral keys, symbol keys and kana / kanji conversion keys, selection /
A character input key such as an execution key is provided,
Various function keys such as a print key operated when executing a print process are provided.

The thermal print head H is, for example, 64
Of dot heating elements arranged in a line and mounted on a carriage which is moved along the platen for paper feeding by the carriage drive motor Mc, from a start end position which is a print start position to a end position. The print head is slid for one print line within the moving range of the print head, and one print line is printed along the platen by the carriage drive motor Mc according to the energization drive process for each line data from the start end position by the thermal head H. One line is printed on the recording paper on the platen.

When one-line printing on the recording paper on the platen is completed, the carriage drive motor Mc
As a result, the carriage is slid to the start position of the printing start and returned, and the platen is rotated by one line interval by the paper feed motor Mp to feed the paper.

In this case, the carriage drive motor Mc
For example, a step motor having four-phase excitation coils A, B, C, D is used, and is driven by the 1-2 phase excitation method.

The fact that the thermal print head H is at the print start position means that the carriage position detecting sensor 1
It is detected by 8 and notified to the control unit (CPU) 11. Here, the thermal print head H is pressed toward the recording paper wound around the platen when sliding in the print direction along the platen, and
The thermal print head H is configured to be separated from the recording paper when the slide is moved to return to the print start position.
The pressing / pulling-off mechanism for the platen is constituted by a cam mechanism (not shown) which is interlocked with the sliding movement of the carriage.

The RAM 14 is provided with a control unit 11 during printing.
A storage area (work area) for various processing data such as a storage area for the excitation step of the carriage drive motor (step motor) Mc, a storage area for format data for setting the format of input document data, and a key input data storage section In addition, a character string (document) data created by an input operation of various character data in the key input unit 12 is provided as a print data storage unit or the like that is stored as print target data.

In the ROM 13, a system program governing the basic operation of the word processor and a related program, for example, a format defined by document data 1 are defined.
In addition to data such as the number of excitation steps that is set to an even number for the entire carriage drive motor (step motor) Mc corresponding to the maximum print width of line printing, a document creation program, a creation document display, a printing program, etc. (not shown). ) Is memorized.

On the other hand, the print data stored in the print data storage section in the RAM 14 is read by the control section (CPU) 11 for each one-line print data and sequentially transferred to the head driver 16a, and this one-line print is carried out. Energization drive of the thermal print head H and carriage motor M for each data
By moving the carriage by c, one line is printed for each line on the recording paper on the platen.

FIG. 2 is a block diagram showing the overall construction of an excitation control circuit for the carriage drive motor Mc of the word processor. FIG. 3 is a diagram showing an excitation signal setting table for 1-2 phase excitation with respect to the carriage drive motor Mc of the word processor.

Inside the print control unit 15 in FIG. 1, an excitation phase control unit 21, a frequency changing unit 22, a clock pulse generator 23, a start / stop circuit 24, as an excitation control system circuit for the carriage drive motor Mc. A forward / reverse rotation circuit 25 is provided.

The excitation phase controller 21 has eight 1-2 phases from "0" to "7" as shown in FIG. 3 according to the timing of generation of the pulse signal supplied from the clock pulse generator 23. Excitation command signal (AD → A → AB → B →
(BC → C → CD → D) is repeatedly generated, and the excitation phase control unit 2 from the carriage motor driver 16b.
Excitation phase corresponding to 1-2 phase excitation command signal generated from 1 (AD phase → A phase → AB phase → B phase → BC phase → C phase → CD
The exciting current is sequentially applied to the phase → D phase).

Then, 1-from the excitation phase control unit 21
The 2-phase excitation command signal is activated from the control unit (CPU) 11.
The generation / stop is controlled according to the motor start / stop signal supplied via the stop circuit 24, and the generation order thereof is controlled according to the forward rotation or reverse rotation command signal supplied via the forward / reverse rotation circuit 25. Is switched to the forward or reverse direction.

Further, "0" generated in the excitation phase controller 21
8 types of 1-2 phase excitation command signals up to "7" are also output to the control unit (CPU) 11, and the control unit 11 constantly monitors the excitation state of the carriage drive motor (step motor) Mc. .

The clock pulse generator 2
The generation period of the pulse signal in 3 is the frequency variable unit 22.
It can be changed by the
It is generated in a cycle corresponding to the motor excitation switching timing synchronized with the one-line printing timing in.

FIG. 4 is a diagram showing a carriage movement state by the carriage drive motor Mc accompanying the printing process of the word processor. In FIG. 4, arrows x0 to x4,
y0 to y4 indicate the moving direction and the moving range of the carriage (print head H), and arrows x0 and y0 indicate the movement of the carriage to the print start position immediately after the start of the printing operation, arrows x1 to x2 and arrow y1 to. y2 is the movement of the carriage in the case of performing printing of the maximum width that can be printed on the recording paper without any line feed in the middle of printing one line (referred to as carriage movement ranges A and B in FIG. 4, these ranges A and B). Have the same length, which is the maximum range of movement of the carriage during printing.), Arrows x3 to x4 and arrows y3 to y4 indicate the movement of the carriage when a line feed is present in the middle of printing one line.

Further, in FIG. 4, A0 and B0 are predetermined carriage standby positions where the carriage is stopped at the time of printing start, AS and BS are print start end positions corresponding to the start position of one line print, and AL and BL are Print end position, AM
Symbols BM and BM indicate folding positions due to a midline feed, and AE and BE indicate end positions of the midline feed print.

A1 and B1 indicate carriage stop positions at the start of printing. Originally, the carriage stands by at the predetermined waiting position A0 or B0, but the position may change when the user touches the carriage. A1 and B1 indicate the carriage standby position in such an irregular case.

As will be described later in detail with the description of the printing operation, the carriage movements indicated by arrows x0 to x4 in the upper half of FIG. A case where the print start end position (AS) is determined together with the position detection is shown. The movement of the carriage indicated by arrows y0 to y4 in the lower half of FIG. 4 indicates that the carriage started from B0 to B1 is the carriage position sensor 18. In spite of the position detection, the stop position (this is the print start end position BS
Becomes ) Is corrected.

An outline of the movement of the carriage during printing of the word processor will be described with reference to FIG. First, after starting from the standby position, the print start position is determined. The determination of the print start end position is performed based on the detection of the carriage position of the carriage position sensor 18 and the detection of the excited state of the carriage drive motor (step motor) Mc by the control unit (CPU) 11.

That is, in the present invention, the carriage drive motor (step motor) Mc driven by 1-2 phase excitation.
Is temporarily stopped in the one-phase excitation state. Therefore, when the carriage position detection sensor 18 detects the carriage position and the control unit (CPU) 11 detects the one-phase excitation state at that time, the point A S is set. The print start end position is defined and printing is performed as x1 to x4, but the carriage position is detected by the carriage position detection sensor 18, but the excitation state is detected by the control unit 11 at that time. If so, go one step further to 1
The printing is temporarily stopped at the phase excitation position, and this position is defined as the print start end position BS, and printing is performed as y1 to y4 below.

When there is no line feed in the middle of printing one line, the control section 11 determines the maximum print width (carriage movement range A and B) determined at the time of formatting from the AS point or the BS point. While driving the print head H only and counting the number of driving steps of the carriage driving motor (step motor) Mc, this is driven (arrows x1 and y1).

Carriage drive motor (step motor) Mc for moving the carriage between the maximum print widths.
The number of driving steps is set to a predetermined even number so that the carriage driving motor Mc is temporarily stopped by one-phase excitation at the printing end positions AL and BL. The control unit 11 counts the number of excitation steps of the carriage drive motor Mc during printing one line from the print start end position, and when this count reaches the predetermined number of steps, the carriage drive motor M
Stop C. The position is the AL point or the BL point.

Even when the carriage is returned (arrow x2 or y2), the control unit 11 counts the number of excitation steps of the carriage drive motor Mc up to the predetermined number of steps starting from the print end position so that the carriage starts printing. Return to position AS or BS (arrow x2 or y2).

Further, if there is a line feed in the middle of printing one line, the control unit 11 causes the carriage drive motor M to start from the print start end position AS or BS determined as described above.
While counting the number of drive steps of c, printing is performed until there is no print data for the line feed on the way (arrow x3 or y3). Then, the control unit 11 detects that there is no print data by the line feed mark, and at the same time, the carriage drive motor M
The excitation state of c is detected, and if it is the one-phase excitation state, the printing end position AE is set as the folding position AM and the carriage is returned by the number of steps counted after the temporary stop (arrow x4
).

When the carriage drive motor Mc at the print end position BE is in the two-phase excitation state, the carriage drive motor is further advanced by one step, and the carriage drive motor is temporarily stopped with the point BM as the turning point. Mc is reversed to restore the number of excitation steps involved in the printing of this line feed.

FIG. 5 is a diagram showing the relationship between the sensor signal from the carriage position detection sensor 18 of the word processor and the 1-2 phase excitation command signal for the carriage drive motor Mc.

That is, when the carriage equipped with the thermal print head H approaches the print start position where the carriage position detection sensor 18 is arranged, the sensor signal becomes a chattering signal Q0 that rapidly repeats "L" and "H", and thereafter. When the carriage reaches the starting end position, the sensor signal becomes the starting end position detection signal Q held at “H”, and the control unit (CPU) 11 detects the sensor signal supplied via the detection circuit 17. Sampling is performed at the excitation switching timing T for the carriage drive motor Mc, and it is determined that the carriage has reached the print start position at the time t0 when the "H" level sensor signal is obtained n times from the start of the chattering signal Q0. To do.

Here, the control unit 11 constantly detects the excitation state of the carriage drive motor Mc, and it is determined that the carriage has reached the print start position based on the sensor signal from the carriage position detection sensor 18. Time t
When the excitation state of the carriage drive motor Mc at 0 is the one-phase excitation state, the position is set as the print start end position (AS in FIG. 4), and when it is the two-phase excitation state,
Further, switching the motor excitation phase for one step,
At the time t1 when switching to the one-phase excitation state, the switching of excitation is stopped, and the carriage is stopped and held at the print start position (BS in FIG. 4).

FIG. 6 is a circuit diagram showing a structure of an exciting current supply circuit of the motor driver 16b for the carriage drive motor Mc of the word processor. The 1-2 phase excitation command signal (AD) from the excitation phase controller 21 in FIG.
->A->AB->B->BC->C->CD-> D) are respectively four excitation phases A, B, C, D of the carriage drive motor Mc.
Transistors Tra, Trb, T interposed between the ground and ground
It is selectively supplied to the base electrodes of rc and Trd, whereby the voltage from the motor power source VM is sequentially applied to the excitation phase corresponding to the transistor turned "ON", whereby the carriage drive motor Mc is rotationally driven. It

In this case, the excitation current supplied from the motor power source VM to each excitation phase A, B, C, D of the carriage drive motor Mc is the drive force control signal supplied from the control unit (CPU) 11. It can be switched in two stages according to the drive force control signal CM.
Is activated, the excitation current IH flowing in each excitation phase of the carriage drive motor Mc becomes a high current value represented by the following equation (1), and the drive force signal "L" causes the drive force control circuit CM to be inactive. In this case, the exciting current IL flowing in each exciting phase of the carriage drive motor Mc has a low current value shown by the following equation (2).

IH = (VM-VCE) / R1 ... Equation (1) IL = VBE / R2 = 0.7 / R2 ... Equation (2) That is, the driving force control circuit CM is operated by the driving force control signal "H". Then, the excitation voltage from the motor power source VM is directly transmitted via the transistor Tr2 to the carriage drive motor Mc.
As a result, the exciting current IH has a high current value as shown in equation (1), and a high motor torque can be obtained.

When the driving force control circuit CM is deactivated by the driving force control signal "L", the exciting voltage from the motor power source VM is applied to the carriage driving motor Mc through the transistors Tr1 and Tr3. The exciting current IL has a low current value as shown in the equation (2), and the motor torque can be suppressed to a low value.

Therefore, a high torque is required to move the carriage along with the actual printing, and when the carriage is moved in the forward CCW direction from the print start end position to the print end position, the carriage drive motor Mc is controlled in driving force. Signal "H"
By supplying and driving the carriage, the carriage can be accurately moved by a high torque, and at the time of returning movement of the carriage in the reverse direction CW to the print start position, which does not require high torque after printing one line. By supplying the driving force control signal "L" to drive the carriage driving motor Mc, the current consumption can be suppressed.

Next, the printing process of the word processor having the above construction will be described. FIG. 7 is a flowchart showing the overall printing process of the word processor. In accordance with the operation of various character input keys in the key input unit 12, desired document data is created and displayed, and stored in the print data storage unit in the RAM 14, the print data stored in the print data storage unit is displayed. When the print key of the key input unit 12 is operated to print out, the print process in FIG. 7 is started, and the carriage drive motor Mc is driven in the reverse direction CW via the print control unit 15 and the carriage drive motor driver 16b. (Step S1).

That is, the start / stop circuit 2 in FIG.
4 outputs a start command signal and the forward / reverse rotation circuit 25 outputs a reverse rotation command signal, so that the excitation phase control unit 21 sends a reverse rotation 1-2 phase excitation command signal (D → CD) to the motor driver 16b. (→ C → BC → B → AB → A → AD), which enables the thermal print head H
The carriage equipped with the print start position (AS or B) from the predetermined standby position (A0 or B0) or the irregular standby position (A1 or B1) in the carriage movement range A.
It is slid in the direction CW of S).

In this case, the driving force control circuit C in FIG.
Since the driving force control signal “L” is supplied to the M from the control unit (CPU) 11, the carriage driving motor Mc
Is driven with a low current consumption IL.

When the carriage is slid to the print start position (AS or BS) and detected by the carriage position sensor 18 (see FIG. 5), the controller 1
1 from the excitation phase control unit 21 to the motor driver 1
It is determined whether the 1-2 phase excitation command signal supplied to 6b is in the 1 phase excitation state (steps S2 → S3).

Here, although it is detected by the carriage position sensor 18 that the carriage has reached the print start position, it is determined that the carriage drive motor Mc at that time is not the one-phase excitation but the two-phase excitation timing. Then, it is further driven in the reverse direction CW until the timing of one-phase excitation for one step, and the carriage drive motor Mc is stopped and held in the state of the one-phase excitation by the stop command signal from the start / stop circuit 24. The position is determined as the print start edge position BS (steps S3 → S4 → S3 →
S5).

When the carriage position sensor 18 detects the carriage, the excitation state of the carriage drive motor Mc is 1
If it is phase excitation, it is stopped and held there, and the position is determined as the print start end position AS (steps S3 → S).
5).

As a result, the carriage drive motor Mc
Is stopped in the state of one-phase excitation with a small exciting current, and the carriage is temporarily stopped corresponding to the print start end position (AS or BS). Here, from the print data storage section in the RAM 14, The print data for the line is read and read into the print buffer in the print control unit 15 (step S
6).

Then, the print data for one line read in the print buffer of the print control unit 15 is 1 from the beginning.
The print data corresponding to the dot lines are read out one by one, the corresponding heating element of the thermal print head H is driven to generate heat, and in response to the start command signal from the start / stop circuit 24 and the forward rotation command signal from the forward / reverse rotation circuit 25. Then, the excitation phase control unit 21 supplies a 1-2 phase excitation command signal for normal rotation to the motor driver 16b step by step, so that the carriage equipped with the thermal print head H prints in the carriage movement range A. 1 dot line width from the starting position A1 is sequentially slid in the forward CCW direction to
One line is printed by repeating the printing for each dot line (steps S7, S8, S9).

In this case, the driving force control circuit C in FIG.
Since the driving force control signal “H” is supplied from the control unit (CPU) 11 to M, the carriage driving motor Mc
Is driven with a high torque by a high excitation current IH.

When the printing of one line by the repeated printing of each dot line is completed, the RAM 14
Based on the presence / absence of unprinted data in the internal print data storage unit, it is determined whether or not printing of all print data is completed (steps S9 → S10).

When it is determined that the printing is not completed because there is unprinted data in the print data storage section in the RAM 14, the carriage movement range A or B corresponding to the maximum width of one line printing is obtained. Whether or not the carriage drive motor Mc has been driven in the forward CCW direction by a predetermined number of steps, that is, the carriage movement position associated with the printing of one line from the print start end position AS or BS is the maximum width of one line. Whether the print end position AL or BL corresponding to is reached is determined by the number of excitation steps for the carriage drive motor Mc (steps S10 → S11).

The number of excitation steps is counted by the control unit 11 starting from the print start position (AS or BS) during printing and stored in the RAM 14. In this case, the predetermined number of steps corresponding to the carriage movement range A or B corresponding to the maximum width of the one-line printing is determined by the format setting of the document data, and the whole is predetermined as an even number of steps. , A carriage drive motor Mc that is stopped in the one-phase excitation state at the print start position (AS or BS), is activated from there, and is driven in the forward direction CCW.
When the predetermined number of steps is reached, that is, when the print end position (AL or BL) is reached, the one-phase excitation is inevitably set.

Here, although the printing of one line is completed,
The carriage has not reached the print end position (AL or BL) corresponding to the maximum width for one line, and for example, as shown by the arrow x3 or y3 in FIG. When it is determined that the printing has been completed, the 1-2 phase excitation command signal supplied from the excitation phase control unit 21 to the motor driver 16b at the time when the printing of one line is completed, causes the control unit 11 to perform the 1 phase excitation. It is determined whether or not it is in the state (steps S11 → S12).

When it is determined that the carriage drive motor Mc is at the timing of the one-phase excitation at the end point of the one-line printing due to the line feed on the way, the print end position AE is set to the turn-back position AM, and the print is stopped and held as it is. (Step S12 → S14).

When it is determined that the carriage drive motor Mc is at the timing of the two-phase excitation instead of the one-phase excitation, the carriage drive motor Mc is further driven in the forward direction CCW from the print end position BE until the timing of the one-phase excitation for one step. The carriage drive motor Mc is advanced to the turn-back position BM, and in response to the stop command signal from the start / stop circuit 24, the carriage drive motor Mc is stopped and held in the one-phase excitation state (steps S12 → S13).
→ S12 → S14).

As a result, the carriage drive motor Mc
Is stopped in the state of one-phase excitation with a small exciting current, and the carriage is temporarily stopped corresponding to the line feed position on the way of the printing of one line.

Then, the carriage drive motor Mc
Is excited in the reverse direction CW, and the carriage moves from the midline feed position of one line print to the print start position (AS or It is slid toward BS) (step S15).

In this case, the driving force control circuit C in FIG.
Since the driving force control signal “L” is supplied to the M from the control unit (CPU) 11, the carriage driving motor Mc
Is driven with a low current consumption IL.

Then, with respect to the number of motor excitation steps required to move the carriage in the forward CCW direction in association with the printing of the immediately preceding line, in the backward CW direction of the carriage toward the printing start end position (AS or BS). It is determined whether or not the carriage has returned to the printing start end position (AS or BS) by determining whether or not the number of motor excitation steps required for the return movement of (1) matches (step S16).

Here, the printing start end position (AS or BS
), The number of motor excitation steps required to return the carriage in the reverse CW direction matches the number of motor excitation steps required to move the carriage in the forward CCW direction in response to the printing of one line immediately before. When the motor Mc is excited again for one phase, the carriage moves to the print start position (AS
If it is determined that the carriage drive motor Mc has returned to BS), the carriage drive motor Mc is stopped and held in the one-phase excitation state by the stop command signal from the start / stop circuit 24, and the next 1
The process proceeds to the line print data printing process (step S16 →
S5-).

That is, even after the carriage is moved back to the print start position (AS or BS) for printing the next one line after printing the one line, the carriage drive motor Mc is driven by the one-phase excitation with a small exciting current. The state is stopped.

On the other hand, at the step S9, it is judged that the printing of one line is completed, and at the same time, at the step S10.
When it is determined that the printing of all print data is not completed in, the carriage drive motor is driven by a predetermined number of even steps corresponding to the carriage movement range A corresponding to the maximum width of one line print, as shown by an arrow x1 in FIG. Mc is forward CCW
Drive to the print start position (AS or B
The carriage movement position for printing one line from S) is 1
Print end position (AL or BL) corresponding to the maximum line width
When it is determined that the process has reached at the timing of one-phase excitation,
In response to the stop command signal from the start / stop circuit 24, the carriage drive motor Mc is stopped and held in the one-phase excitation state (steps S11 → S17).

As a result, the carriage drive motor Mc
Is inevitably stopped in the one-phase excitation state in which the excitation current is small, and the carriage is set at the end position (AL or B) for printing one line
It is suspended corresponding to L).

Then, the carriage drive motor Mc
Is excited in the reverse direction CW, and the carriage starts from the end position (AL or BL) of the printing of one line to the printing start end for the next printing of one line, as shown by arrow x2 or arrow y2 in FIG. It is slid toward the position (AS or BS) (step S18).

In this case, the driving force control circuit C in FIG.
Since the driving force control signal “L” is supplied to the M from the control unit (CPU) 11, the carriage driving motor Mc
Is driven with a low current consumption IL.

Then, the print start position (AS or BS
) To the print end position (AL or BL) corresponding to the predetermined motor excitation step number (even number) required to move the carriage in the forward CCW direction with printing one line, the print start position (AS or It is determined whether or not the carriage has returned to the print start position (AS or BS) by determining whether or not the number of motor excitation steps required for the return movement of the carriage toward BS) in the reverse direction toward BS) is the same. (Step S19).

Here, the print start end position (AS or BS
), The number of motor excitation steps required for the return movement of the carriage in the reverse direction CW coincides with a predetermined number of motor excitation steps (even number) corresponding to the maximum width of the one-line printing, and the carriage drive motor Mc is restarted. When it is determined that the carriage has returned to the print start position (AS or BS) in the one-phase excitation state, the carriage drive motor Mc is driven by the stop command signal from the start / stop circuit 24.
It is stopped and held in the phase excitation state, and the process proceeds to the printing process of the next one-line print data (steps S19 → S5).

Also in this case, the carriage drive motor Mc
Is stopped in the one-phase excitation state where the excitation current is small. In this way, the processes of steps S5 to S19 are repeated, and R
With the print data stored in the print data storage unit in the AM 14 being read out line by line and printed out, in step S10, there is no unprinted data in the print data storage unit, and printing ends. When it is determined that the print start position is the print start end position (A0 or B0) from the predetermined standby position (A0 or B0).
S or BS) side, the carriage drive motor Mc is excited and driven in the forward CCW direction, and the carriage is
It is slid to a predetermined standby position (A0 or B0) (steps S10 → S20).

In step S10, when there is no unprinted data in the print data storage section and it is determined that printing has ended, the position of the carriage corresponding to the printing end position is set to the predetermined standby position (A0 When the print end position (AS or BS) is closer than B0), the carriage drive motor Mc is excited and driven in the reverse direction CW, and the carriage is slid to a predetermined standby position (A0 or B0). (Steps S10 → S20).

Therefore, according to the word processor having the above-described structure, the carriage on which the thermal print head H is mounted is excited and driven by the carriage drive motor Mc according to the 1-2 phase excitation method, so that one line can be printed along the platen. The carriage position sensor 18 is used to slide the carriage in the corresponding carriage movement range A.
When the carriage drive motor Mc is in the two-phase excitation state when the carriage is moved to the print start position (AS or BS) detected by, the motor is further excited by one step and stopped and held in the one-phase excitation state. The normal drive amount of the carriage drive motor Mc from the start position of printing (AS or BS) to the end of printing one line, and the return to the start position of start of printing (AS or BS) after the end of printing one line. The reverse drive amount is
Both are determined by an even number of excitation steps, and when the motor Mc is temporarily stopped when the carriage is folded back, it is always stopped and held in the one-phase excitation state. Therefore, the current consumption for exciting the carriage drive motor Mc is increased. Can be reduced, and furthermore, the temperature rise of the motor itself can be suppressed.

Further, according to the word processor having the above structure, when the thermal print head H moves the carriage in the forward CCW direction, the carriage drive motor Mc outputs a high torque by the drive force control signal "H". The carriage drive motor Mc is driven at a low exciting current by the driving force control signal "L" when the carriage is moved in the reverse direction CW only when the carriage is returned to the print start end position. It is possible to further reduce the current consumption for exciting and driving the drive motor Mc, and further suppress the temperature rise of the motor itself.

FIG. 8 is a block diagram showing the overall construction of an excitation control circuit for a carriage drive motor Mc which is another embodiment of the word processor. FIG. 9 is a timing chart showing a motor excitation state when an excitation control circuit for a carriage drive motor Mc which is another embodiment of the word processor is used.

That is, in the excitation control circuit according to another embodiment of the present invention, the first changeover switch SW1 is provided in the pulse signal supply line from the clock pulse generator 23 to the excitation phase control unit 21, and the excitation phase control unit is also provided. A second changeover switch SW2 is provided on the D-phase excitation command signal supply line from 21 to the motor driver 16b.

Then, in the rotational driving state of the carriage drive motor Mc, the pulse signal from the clock pulse generator 23 is supplied to the excitation phase control section 21 via the terminal k1 of the first switch SW1, and the motor driver 16b. The excitation phase controller 21 is connected to the D phase signal supply terminal of
The excitation command signal for the D phase from is supplied from the terminal k1 of the second switch SW2.

When the carriage drive motor Mc is stopped, the switch control signal from the control unit (CPU) 11 switches both the first and second switches SW1 and SW2 to the terminal k2 side, and the clock pulse generator 23 The pulse signal from the direct D of the motor driver 16b
It is configured to be supplied to the phase signal supply terminal.

In this case, the frequency of the pulse signal generated by the clock pulse generator 23 depends on the control signal from the control unit (CPU) 11 and the frequency variable unit 2
2 is variably set via the drive motor 2. In the rotation driving state of the carriage driving motor Mc, the frequency is set in synchronization with a predetermined motor excitation timing, and in the stopped state of the carriage driving motor Mc, the stopping force of the motor Mc is changed. It is set to a frequency that can be secured.

Therefore, by using the excitation control circuit according to the other embodiment of the present invention, when the carriage drive motor Mc is stopped, the excitation current is continuously supplied to a certain excitation phase of the motor. It is not necessary to supply it as a pulse signal, so that heat generation due to motor stop can be suppressed.

[0089]

As described above, according to the printing apparatus according to the first aspect of the present invention, when the driving of the step motor by the 1-2 phase excitation is stopped in order to stop the carriage during printing. When the excitation state of the step motor detected by the detection means is one-phase excitation, the one-phase excitation state is maintained, and when the excitation state of the step motor detected by the detection means is two-phase excitation, the one-phase excitation state is maintained. Since the stepping motor is stopped and controlled so that the one-phase excitation state is maintained after the change to, the current consumption of the motor is reduced and its temperature rise is also reduced.

According to a second aspect of the present invention, there is provided the printing apparatus according to the first aspect, wherein the step motor is further excited by one phase, and the start end of the moving range of the carriage is reached. When moving from the position, since the movement within the range to the carriage end position is controlled by a predetermined even number of steps, at the carriage movement start end position and movement return position during printing, the step motor is always It is stopped at the 1-phase excitation position, and it becomes possible to reduce the consumption current and suppress the heat generation.

According to a third aspect of the present invention, there is provided the printer according to the first aspect or the second aspect, further comprising the step motor when the carriage is moving in the forward path and the return path. Since the exciting current value of is changed, the total current consumption of the motor can be reduced by lowering the exciting current during the backward movement, which simply returns to the movement start position, compared with the forward movement of the carriage where actual printing is performed. It will be reduced and the heat generation will be suppressed.

According to the printing apparatus of the fourth aspect of the present invention, in order to stop the carriage during printing,
-When stopping the driving of the step motor by -2 phase excitation, a pulse train is added to the 1 phase and the stop position is held when the excitation is stopped. The heat generation of the will be suppressed.
Therefore, according to the present invention, it is possible to reduce current consumption in the step motor and suppress heat generation of the motor itself.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic circuit of a word processor equipped with a printing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of an excitation control circuit for a carriage drive motor Mc of the word processor.

FIG. 3 is a diagram showing an excitation signal setting table for 1-2 phase excitation with respect to a carriage drive motor Mc of the word processor.

FIG. 4 is a diagram showing a carriage movement state by a carriage drive motor Mc accompanying the printing processing of the word processor.

FIG. 5 is a diagram showing a relationship between a sensor signal from a carriage position detection sensor of the word processor and a 1-2 phase excitation command signal for a carriage drive motor Mc.

FIG. 6 is a circuit diagram showing a configuration of a motor driver excitation current supply circuit for the carriage drive motor Mc of the word processor.

FIG. 7 is a flowchart showing the overall printing process of the word processor.

FIG. 8 is a block diagram showing an overall configuration of an excitation control circuit for a carriage drive motor Mc which is another embodiment of the word processor.

FIG. 9 is a timing chart showing a motor excitation state when an excitation control circuit for a carriage drive motor Mc which is another embodiment of the word processor is used.

[Explanation of Codes] 11 ... Control Unit (CPU), 12 ... Key Input Unit, 13 ... ROM, 14 ... RAM, 15 ... Print Control Unit, 16a ... Paper Feed Motor Driver, Mp ... Paper Feed Motor, 16b ... Head Driver , H ... Thermal print head, 16c ... Carriage drive motor driver, Mc ... Carriage drive motor, 17 ... Detection circuit, 18 ... Carriage position detection sensor, 19 ... Liquid crystal display section, 21 ... Excitation phase control section, 22 ... Frequency variable section , 23 ... Clock pulse generator, 24 ... Start / stop circuit, 25 ... Forward / reverse circuit, A, B ... Carriage movement range, A0, B0 ... Predetermined carriage standby position, AS, BS ... Printing start position, AL, BL ... Printing End position, AM, BM ... Halfway line break return position, AE, BE ... Halfway line end position, A1, B1 ... Anomalous carry Standby position, Q ... Print start end position detection signal, Q0 ... Chattering signal, CM ... Driving force control circuit, SW1 ... First changeover switch, SW2 ... Second changeover switch.

Claims (4)

[Claims] 1. A step motor for reciprocating a carriage having a print head in the width direction of a recording sheet, a motor driving means for driving the step motor by 1-2 phase excitation, and the step motor by the motor driving means. Detection means for detecting the excitation state of the stepping motor, and when stopping the driving of the step motor to stop the carriage during printing, when the excitation state detected by the detection means is one-phase excitation, the excitation state is detected. And a control means for holding the excitation state, and holding the excitation state until the excitation state detected by the detection means is changed to the one-phase excitation when the excitation state is two-phase excitation. Printing device. 2. A position detecting means for detecting the position of the carriage at a predetermined position of a movement path of the carriage, and a motor driving means based on information of the position detecting means at the start of printing. Start position determining means for determining the position of the carriage where the step motor is excited by one phase as the start position of the moving range of the carriage, and an even number of steps of the step motor which is predetermined from the start position during printing. 2. The second control means for controlling the motor drive means to move the carriage within a range up to the end position of the carriage where the carriage is moved. Printing device. 3. The printing apparatus according to claim 1, further comprising an exciting current changing unit that changes an exciting current value of the step motor when the carriage moves in a forward path and a backward path. . 4. A step motor for reciprocating a carriage equipped with a print head in the width direction of a recording sheet, a motor drive means for driving the step motor with 1-2 phase excitation, and the carriage being stopped during printing. For this purpose, when the step motor is stopped, a control means for stopping the excitation by the motor driving means and applying a pulse train to one phase of the step motor is provided.