JPH03224762A - Printer - Google Patents

Abstract

PURPOSE:To make the whole device compact by supplying a drive current to a drive force generation device which rotates an internally hollow platen roller from an outside device and printing a medium to be transported by the platen roller. CONSTITUTION:A platen roller 1 is an internally hollow cylinder in which two drive coils are provided inside its external frame 1a. An excitation current (drive current) is supplied to the drive coil 3 from the platen roller 1 through a lead wire 4. The excitation current obtained through a drive circuit which drives a stepping motor 2 is transmitted to a contact spring 6 through a connection cable 8, then is supplied to the drive coil 3 through a sliding contact 5 and the lead wire 4. As a result, a rotating magnetic field is generated in a stator part 11, and a magnetic energy is generated between the rotating magnetic field and a magnetic field is generated by multipolar magnetization of a rotor part 12. This magnetic energy is converted to a mechanical energy by the rotor part 12 and the external frame 1a of the platen roller 1 is rotated. Thus a printing sheet fed by rotation of the external frame 1a is thermally printed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a printer device such as a thermal printer, and is particularly suitable for use in a portable terminal device such as a day terminal. This invention relates to a printer device.

(Prior Art) Conventionally, stepping motors, which can be easily controlled for positioning, have been frequently used as platen drive motors in printer devices.

FIG. 9 shows a thermal printer in which a platen roller is driven by a stepping motor.

In this thermal printer, the stepping motor 3
1 is attached to the left side surface of the platen support frame 32, and is configured to start (start) rotation by supplying excitation current from the drive circuit 33.

The driving torque of this stepping motor 31 is
4 to the platen roller 35, thereby causing the platen roller 35 to rotate.

On the other hand, the thermal head 36 heats the surface of the printing paper (medium) P fed onto the platen roller 35 by selectively heating a heating resistor in response to a printing signal from a driver circuit (not shown). It is designed to be printed.

FIGS. 10(a) and 10(b) show a handy terminal equipped with the above-mentioned thermal printer as an example of a portable terminal device.

Handy terminals are carried around by workers in factories, for example, to input production management information, quality control information, etc. on-site, transmit this information to a host computer, and print out the results of calculations based on the above information. The above-mentioned thermal printer 41 is mounted on the upper part, and a liquid crystal display (LCD) 42 is provided below for displaying various data, and further below, various data, command information, etc. are input. A keyboard 43 is provided.

However, the thermal printer 41 used in this type of handy terminal has a configuration in which the stepping motor 31 is attached to the left side of the platen support frame 32, as described above.

For this reason, even if an ultra-small stepping motor 31 is used, the diameter of the stepping motor 31 is approximately 20 m due to installation.
m, and requires a space of approximately 10 to 15 mm in length.

As described above, in existing thermal printers, the presence of a stepping motor is the biggest factor that prevents overall miniaturization, and the shape of the left and right sides of the thermal printer is unbalanced, which in turn affects the external design of the handy terminal. There were drawbacks such as restrictions on

(Problem to be solved by the invention) As mentioned above, in the conventional thermal printer,
The presence of the stepping motor was the biggest factor preventing the overall miniaturization, and there were also disadvantages such as the left and right shapes of the thermal printer becoming unbalanced, which in turn restricted the external design of the portable terminal device. .

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a printer device that can be downsized as a whole and does not impose restrictions on the external design of a portable terminal device.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the printer device of the present invention includes a platen roller having a hollow interior and a platen roller provided inside the platen roller. generating means for generating a driving force for rotating the platen roller; supply means for supplying a driving current to the generating means from outside the platen roller; and printing on a medium conveyed by the platen roller. It consists of a printing means.

(Function) By using the above-described means, the present invention does not require a space for installing the generating means, so that the external dimensions of the printer device can be significantly reduced, and the shape of the printer device can be made horizontally symmetrical. This makes it possible.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a platen roller according to the present invention. In this case, the platen roller 1 has, for example, a laminated core type plate in the internal cylindrical space of its outer frame 1a.
It has a configuration in which an M-type stepping motor (platen drive motor) 2 is mounted.

That is, the platen roller 1 has a cylindrical shape with a hollow interior. Inside the outer frame 1a, two drive coils 3. ...is provided.

Drive coil 3. ..., each has a lead wire of 4°.
An exciting current (
drive current) is supplied.

That is, as shown in FIG. 2, on the right side of the outer frame 1a of the platen roller 1, there are, for example, five sliding contacts 5.
．． ...is provided. Each of these sliding contacts 5... is connected to the lead wire 4. ···It is connected to the.

In addition, the sliding contact 5. Each of the contact springs 6
．． One end of ... is to be contacted. This contact spring6. ... The other end is fixed to the platen support member 7 and is connected to a drive circuit, which will be described later, via a connection cable 8.

The above drive coil 3. ... is for generating a rotating magnetic field. That is, drive coil 3. ... is the slot 1 of each lamination technique of the laminated core 9, as shown in FIG.
The stator portion 11 is wound around the laminated core 9 to form a stator portion 11. The stator section 11 is fixed to the inner wall of the outer frame 1a of the platen roller 1.

On the other hand, the rotor portion 12 of the stepping motor 2 is fixed to a rotor shaft 13 provided at the center of the platen roller 1. That is, as shown in FIG. 4, the rotor section 12 has a cylindrical magnet 15 attached to the roller shaft 13 via an auxiliary member 14 made of a non-magnetic material such as plastics.
It has a configuration in which it is attached. The outer peripheral surface of the cylindrical magnet 15 is multi-pole magnetized and has approximately 50 magnetic poles. The rotor shaft 13 is fixed to the platen support member 7.

The outer frame 1a of the platen roller 1 described above is made of plastic, and a thin rubber is wrapped around the cylindrical surface to provide friction between the platen roller 1 and the printing paper.

The platen roller 1 is slidably attached to the rotor shaft 13 by a spring washer 17 and a tension washer 18 that apply preload to the bearing 16.

FIG. 5 shows a drive circuit (supply means) for driving the stepping motor 2. As shown in FIG.

This drive circuit includes a clock pulse generator 21 that generates a pulse waveform of an arbitrary period, a frequency variable section 22 that adjusts the rotational speed of the stepping motor 2 by changing the frequency of the clock pulse generator 21, and a frequency variable section 22 that adjusts the rotation speed of the stepping motor 2. A startup control section 23 that controls startup; an excitation control section 24 that generates an excitation current to be applied to the drive coil 3 of the stepping motor 2 in response to a startup signal from the startup control section 23; It is composed of a power amplifying section 25 that amplifies the power to a level necessary for starting the stepping motor 2.

Therefore, the excitation current obtained by the drive circuit is transmitted through the connection cable 8. It is transmitted to the contact spring 6°... through... And this contact spring 6. ... to the sliding contact 5. ...and lead wire 4. ... through the drive coil 3. ..., a rotating magnetic field is generated in the stator section 11.

Then, magnetic energy is generated between this rotating magnetic field and the magnetic field due to the multipolar magnetization of the rotor section 12, and this is converted into mechanical energy by the rotor section 12. The outer frame 1a of the platen roller 1 is rotated by this mechanical energy. Then, thermal printing is performed by a not-shown thermal head (printing means) on the printing paper fed by the rotation of the outer frame 1a.

Here, connection cable 8. The configuration of ... will be explained.

Connection cable 8. ...The breakdown is A phase, B phase, A phase,
B phase and COM (common line). These signals having different phases are transmitted to the drive coil 3. of the stator section 11, as shown in FIG. Each winding L forming...
1 to L4.

In this case, drive coil 3. . . ., the winding L1 and the winding L3, the winding L2 and the winding L4 are respectively connected to the laminated core 9.
The inside is bifilar wound. For this reason,
The phase of the winding L1 and the winding L3, the winding L2 and the winding L4
As shown in FIG. 7, the phases of the windings L1 and L2 are different from each other by 180", and the windings L3 and L4 are arranged so that the phase difference is 90". has been done. Therefore, the stator section 11 is rotated in steps by supplying the excitation current to the winding L1, the winding L3, the winding L2, and the winding L4, shifted by 90 degrees.

By the way, in this method in which the stepping motor 2 is mounted inside the platen roller 1, it is difficult to apply a speed reduction mechanism. Therefore, it is necessary to reduce the step angle of the stator section 11.

Therefore, in this embodiment, the number of magnetic poles of the cylindrical magnet 15 is increased, and as shown in FIG.
-A two-phase excitation force type is adopted. However, if the number of magnetic poles is too large, the magnetic energy will be reduced, so
The limit is about 50 poles.

According to the above-described 1-2 phase excitation force formula, the step angle can be made half of that in the case of 1-phase excitation. As a result, when the number of magnetic poles is set to 50 and the 1-2 phase excitation force formula is used in combination, the step angle θ becomes -1.8''.

Therefore, the paper feeding speed V of the platen roller 1 incorporating the stepping motor 2 can be determined by the following formula, assuming that the frequency of the clock pulse is 100 PPS and the diameter of the outer frame 1a of the platen roller 1 is 12 mmφ.

That is, −18.8 mm/s In this manner, the present invention achieves a paper feeding speed comparable to that of a printer device that employs a conventional deceleration mechanism.

As described above, the configuration is such that the stepping motor is mounted inside the platen roller.

That is, the stator portion of the stepping motor is integrated with the inner wall of the outer frame of the platen roller, and the rotor shaft is fixed to the platen support member, so that the outer frame of the platen roller rotates. This makes it possible to eliminate the need for a space for installing a motor, which is a bottleneck when designing a printer device. Therefore, the external dimensions of the printer device itself can be significantly reduced, and the external dimensions of the printer device can be made laterally symmetrical.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, the external dimensions of the printer device itself can be significantly reduced, and the external dimensions of the printer device can be made symmetrical. Therefore, it is possible to provide a printer device that can be miniaturized as a whole and does not impose restrictions on the external design of the portable terminal device.

[Brief explanation of drawings]

1 to 8 show an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a platen roller in a printer device of the present invention, and FIG. 2 is a side view of the platen roller. Figure 3 is a diagram showing the configuration of the stator section, Figure 4 shows the configuration of the stator section.
Figure 5 is a block diagram showing the configuration of the rotor section, Figure 5 is a block diagram showing the configuration of the drive circuit, Figure 6 is a diagram shown to explain the connection state of the drive coil, and Figure 7 is each winding of the drive coil. L
l, L2. L3. A wiring diagram shown to explain the relationship of L4, Fig. 8 is a diagram shown to explain the drive sequence of the 1-2 phase excitation force type, and Figs. 9 and 10 show the conventional technology and its problems. FIG. 9 is a block diagram showing an example of a thermal printer in which a platen roller is driven by a stepping motor, and FIG. 10 is an external view of a handy terminal on which the thermal printer is mounted. DESCRIPTION OF SYMBOLS 1... Platen roller, 1a... Outer frame of platen roller, 2... Stepping motor (generating means), 3...
... Drive coil, 4... Lead wire, 5... Sliding contact, 6... Contact spring, 7... Platen support member, 8...
...Connection cable, 9...Laminated core, 11...Stator part, 12...Rotor part, 13...Rotor shaft, 1
5... Cylindrical magnet, 21... Clock pulse generator, 22... Frequency variable section, 23... Starting control section, 24... Excitation control section.

Claims (3)

[Claims] (1) A platen roller having a hollow interior, a generating means provided inside the platen roller for generating a driving force for rotating the platen roller, and a driving force applied to the generating means from outside the platen roller. A printer device comprising: supply means for supplying current; and printing means for printing on a medium conveyed by the platen roller. (2) The printer device according to claim 1, wherein the generating means is a stepping motor configured inside the platen roller. (3) The stator core of the stepping motor is fixed to the outer frame of the platen roller, while the rotor shaft is fixed to a supporting member of the platen roller, and the platen roller is configured to rotate when the motor is started. The printer device according to claim 2, characterized in that: