JPH0363517B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a stepping motor for driving a carriage, a paper feed mechanism, a platen, etc. of a printing device, and a method for controlling the driving device. This invention relates to a control method for aligning the beginnings of printed lines when printing after paper feeding.

[Background of the invention]

As a conventionally known printer, there is a thermal printer as shown in FIG. 3, for example.

In this figure, 1 is a frame forming the main body, 2 is a platen around which recording paper is wound, and 3 is a platen rubber attached to the front surface of the platen 2 at a printing position. Reference numeral 4 designates a thermal head disposed to face the platen 2, 5 a tape cassette, and 6 a cassette holder that holds the tape cassette 5 and constitutes a cassette shift mechanism to be described later. The entire cassette shift mechanism is constructed using a carriage 7, which will be described below, located below the tape cassette 5.
Supported by 7a is a rotatable shaft extending along the platen 2 and passing through a carriage 7, which will be described later. Although not shown, a cam and a worm wheel are integrally provided at the left end of the shaft 7a, and a worm (not shown) that engages with the worm wheel is rotated by a stepping motor 8. This shaft 7a is designed to rotate.

Further, reference numeral 9 denotes a lever having one end that engages with a cam integrally provided on the shaft 7a, which is connected to the support shaft 1.
0, and the other end engages with the body of a slider 11 that is movable in the horizontal direction in the drawing. Note that this slider 11 is rotatably provided integrally with the output shaft of a stepping motor 12, and gears are formed on both sides.
The gears on both sides of the slider 11 are drive gears 1 loosely fitted to the output shaft of the stepping motor 12.
3 and 14 to form a serration mechanism 35.

Further, 15 is a driven gear that engages with the drive gear 13 and rotates integrally with the drive gear 13, and has a bevel gear 16 on its side. 17 is bevel gear 16
It is a bevel gear that engages with the pulley 19 and is integrally provided with a pulley 19 having a protrusion 18 on the circumferential side. 20 is a metal belt whose both ends are connected to the carriage 7, which will be described later.
It has a square hole 21 that engages with the protrusion 18 of the pulley 19. 22 is placed on the opposite side of the pulley 19,
This is a pulley around which the metal belt 20 is wound.

The metal belt 20 and pulleys 19, 2 described above
2. The bevel gear 17, the driven gear 15 having the bevel gear 16, and the slider 11 are connected to the carriage 7 that holds the thermal head 4, tape cassette 5, etc.
along the platen 2, that is, in the left-right direction in the drawing, the drive gear 1 is connected to the stepping motor 12.
3 constitutes a carriage transfer mechanism 33 that moves the carriage through the carriage.

Further, 23 is a driven gear that engages with the drive gear 14, has a small diameter gear 24 on the side, and is loosely fitted to the paper feed shaft 25 so as to be rotatable. A gear 26 engages with the gear 24, and has a small diameter gear 27 on the side. 28 is a gear that engages with gear 27;
It is rotatably mounted integrally with the paper feed shaft 25. A sprocket 29 is provided integrally with the paper feed shaft 25, and has protrusions 30 on the same surface that are fitted into holes formed at both edges of the recording paper, for example.

The above-mentioned sprocket 29, paper feed shaft 25, gear 28, gear 26 having gear 27, driven gear 23 having gear 24, and slider 11 move the recording paper 31 shown by the chain double-dashed line wound around the platen 2 to the carriage 7. The stepping motor 12 is moved in the direction perpendicular to the feeding direction of the
A paper feeding mechanism 3 that sends paper via a drive gear 14 connected to
4.

Although not particularly shown, the thermal head 4
As the shaft 7a rotates, the platen 2 is pressed against or released from the platen 2 via a cam (not shown) or the like.

Next, the carriage transfer operation and paper feeding operation of this thermal printer will be described.

(1) [Carriage transfer operation] As the stepping motor 8 shown in FIG. 3 rotates, the lever 9 moves counterclockwise as shown in FIG. rotate in the direction. Therefore, the slider 11 engaged with the lever 9 of the serration mechanism 35 moves to the left in FIG. 1, and the gear formed on the left side of the slider 11 engages with the drive gear 13. . Here, when the stepping motor 12 rotates, the slider 11 rotates, and as the driving gear 13 rotates, the driven gear 15, that is, the bevel gear 16 rotates, and as the bevel gear 16 rotates, the bevel gear 17, that is, the pulley 19 rotates. rotates. When the pulley 19 rotates, the metal belt 20 moves, thereby causing the tape cassette 5, thermal head 4,
Carriage 7 equipped with cassette shift mechanism etc.
moves in the left-right direction in FIG. 3, that is, along the platen 2.

(2) [Paper feeding operation] When the stepping motor 8 shown in FIG. 3 rotates, the lever 9 moves around the spindle 10 via a worm, a worm wheel, and a cam (not shown) into the state shown in FIG. 3, i.e. It rotates clockwise from the state in the carriage drive operation described above. Therefore, the slider 11 engaged with the lever 9 moves to the right in FIG. 3, and the gear formed on the right side of the slider 11 engages with the drive gear 14. Here, the pulse motor 12
When the slider 11 rotates, the slider 11 rotates, and as the slider 11 rotates, the gears 14, 23, 2 rotate.
4, 26, 27, 28 rotate, and the paper feed shaft 25
As the paper feed shaft 25 rotates, the sprocket 29 rotates, whereby the recording paper 31 wound around the platen 2 is moved by a predetermined amount, for example, one line, perpendicular to the moving direction of the carriage 7. It is sent in the direction of arrow 32.

Although not specifically mentioned here, the stepping motor 8 is also used to shift the tape cassette 5 by rotating the shaft 7a.

Incidentally, in this conventional printer, the stepping motor 12 is used to transport the carriage 7 and drive the paper feeding mechanism as described above. A stepping motor is also called a pulse motor, and is configured so that when one pulse is sent to the stepping motor drive device, the motor rotates by a certain angle (step angle). ) Compatible with digital control and suitable as an incremental drive motor.

(2) Since it rotates in synchronization with an external input signal, it can also be used as a variable speed synchronous motor.

(3) The generated torque is large relative to the moment of inertia of the rotor, and the start-up ability is far superior to that of ordinary synchronous motors. Also, the resistance torque against external forces that try to maintain a certain position is large.

(4) Unlike DC motor brushes, there is no need to worry about mechanical wear and maintenance.

Due to these advantages, it has been increasingly applied to printers, X-Y plotters, etc. in recent years. The above conventional example also uses a stepping motor for this reason, but when using this type of motor, when printing after manually feeding the paper, the beginnings of the printed lines may not line up. There is a problem that it is difficult to print, and it looks bad when printed.

This is because the slider 11 of the serration mechanism 35 controls the paper feed when you manually feed the paper after printing a certain line, or when you manually feed the paper again to increase the paper advance after automatically feeding the paper. Since the gear located on the drive gear 14 side and formed on the right side of the slider 11 is engaged with this drive gear 14, and the stepping motor 12 is turned off, the paper feed shaft must be manually moved. 25 to feed the paper, the rotor 12a of the stepping motor 12 rotates accordingly, and as shown in FIG. 4, the relative positional relationship between the rotor 12a and the stator 12b shifts, making it impossible to match the phases. It is from. If the rotor 12a and stator 12b are not in phase as described above, even if a predetermined phase is excited and printing is performed, the rotor 12a and stator 12b are out of alignment, resulting in a deviation in the printing start position.

[Purpose of the invention]

The present invention has been made in view of the actual situation in the prior art, and its purpose is to ensure that even if printing is started after manual paper feeding, the printing start position will not shift and that the beginning of the printing line will be properly aligned. It is an object of the present invention to provide a method for controlling a printing device that is uniform.

[Summary of the invention]

To achieve this object, the present invention includes a frame forming a main body, a platen against which the recording paper comes into contact, a carriage movable along the platen, and a frame mounted on the carriage and arranged to face the platen. a paper feed mechanism that feeds recording paper between the print head and the platen, cooperating with the platen or independently of the platen;
In a printer equipped with a stepping motor that transports a carriage and drives a paper feed mechanism, and a drive means that transmits the driving force of the stepping motor to the carriage transport mechanism or paper feed mechanism via a serration mechanism, When printing after paper feeding, the serration mechanism is located on the paper feeding side, and before switching to the carriage transfer mechanism side, the stepping motor is energized for a predetermined number of steps to perform normal paper feeding. After the stepping motor is returned by one step to perform reverse paper feeding, the serration mechanism is moved toward the carriage transport mechanism to perform printing or carrying.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of controlling a printing apparatus according to the present invention will be explained below with reference to the drawings. FIG. 1 is an explanatory diagram showing the relationship between the excitation phases of the stator and rotor, showing the control method of the present invention, and FIG. FIG. 4 is an example of a sequence table for two-phase excitation of the four-phase stepping motor shown in FIG. 2.

The printing device of the present invention is equivalent to the conventional printing device shown in FIG. 5, and differs only in the method of controlling the stepping motor 12. Therefore, the following description will specifically take this stepping motor 12 as an example. Descriptions of other parts of the printer will be omitted.

The stepping motor 12 shown as an embodiment in FIGS. 2 and 3 has four phases, and is operated with two-phase excitation (two-phase excitation), which operates while always exciting two phases.
FIG. 2 shows the relationship at a stable point between the teeth of the stator 12b and the rotor 12a in -phase excitation.

First, when the recording paper 31 is fed by rotating the paper feed shaft 25 in the printer 1 shown as a conventional example,
As mentioned above, the rotor 1 of the stepping motor 12
2a is rotated by the rotation of the paper feed shaft 25, and the relative relationship with the energized phase of the stator 12b is disrupted. For example, as shown in FIGS. 1 and 3, the excitation start phase ( Energizing phase) When A is the I phase as shown in Fig. 1, and assuming that the drive phase B of the rotor 12a is actually in the phase position due to the above rotation, the excitation start phase A is energized to print. Even when started, the rotor 12a does not rotate or moves in an uncertain manner. Therefore, the carriage 7 is not properly controlled and the print opening position is shifted. Here, as shown in FIG. 1, for example, if the energized phase A is energized and sent (rotated) two steps, as can be seen from the sequence table in FIG. ) B and stator 1
The predetermined correlation of the energized phase A of 2b is established again. Therefore, when the stator 12b is energized again and the paper is fed back two steps to perform reverse paper feeding, the energization phase A and drive phase B are aligned and return to the printing start position, and the serration mechanism 35
The gear of the slider 11 is engaged with the drive gear 13 on the carriage transfer side to start printing. In this way, even after manually feeding the paper, the correlation between the energized phase and the drive phase of the stepping motor 12 is maintained, so that the print opening position does not shift. Therefore, it is possible to provide beautiful printed matter in which the beginnings of lines are always aligned.

In this embodiment, since a four-phase stepping motor 12 with two-phase excitation is used, if the motor is excited in at least two steps, the corresponding energized phase A
and drive phase B are obtained, so we have shown an example of driving in two steps, but it is also possible to drive in two or more steps, and in the case of one-phase excitation, it is better to drive in at least four steps, so the predetermined step is This should be determined by taking into consideration the number of phases of the stepping motor and the number of excitation phases.

Further, although the present embodiment and the conventional example use a thermal printer, the method of the present invention can be applied to, for example, an electrostatic printer, a discharge destruction printer,
The invention is applicable not only to non-impact printers such as energized printers, but also to impact printers such as wire dot printers and type selection printers.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, after manually feeding the paper, the stepping motor is energized to feed the paper in the forward direction by a predetermined step, and then to feed the paper in the reverse direction by the predetermined step. By switching the serration mechanism to the carriage transport side and starting printing after the printing is finished, the printing start position will not shift at all times, and the beginning of each printing line will be neatly aligned to provide beautiful printed matter. be. Furthermore, since the stator and rotor are perfectly aligned in phase, there is also the secondary effect that the gears of the serration mechanism mesh smoothly.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the relationship between the stator and rotor excitation phases showing the control method of the present invention, and FIG.
A schematic explanatory diagram showing an example of the relative positional relationship and magnetic flux distribution between the stator and rotor in the case of two-phase excitation of a phase stepping motor. Figure 3 shows a state in which the rotor rotates and loses sight of the energized phase. A schematic explanatory diagram showing the fourth
The figure is an example of a sea case table for two-phase excitation of the four-phase stepping motor shown in FIG. 2, and FIG. 5 is a plan view showing an overall outline of a conventional thermal printer. DESCRIPTION OF SYMBOLS 1... Frame, 2... Platen, 3... Thermal head, 7... Carriage, 12... Stepping motor, 12a... Rotor, 12b... Stator, 33... Carriage transfer mechanism, 34...
Paper feed mechanism, 35... serration mechanism.

Claims (1)

[Claims] 1 A frame forming the main body, a platen on which the recording paper comes into contact, a carriage movable along the platen, a print head attached to the carriage and arranged to face the platen, and a print head that works together with the platen. Alternatively, a paper feeding mechanism that feeds the recording paper between the print head and the platen independently of the platen, a stepping motor that transports the carriage and drives the paper feeding mechanism, and the driving force of this stepping motor is transmitted through a serration mechanism. In a printer equipped with a carriage transport mechanism or a drive means for transmitting power to the paper transport mechanism, when printing after manually transporting paper, the serration mechanism is located on the paper transport side and the serration mechanism is positioned at a predetermined position before switching to the carriage transport mechanism side. The stepping motor is energized by a predetermined number of steps to feed the paper forward, and then the stepping motor is returned by a predetermined number of steps to feed the paper in the reverse direction, and then the serration mechanism is moved to the carriage transfer mechanism. A method of controlling a printing device characterized by printing or carrying.