JPH03182372A - Line thermal printer - Google Patents

Abstract

PURPOSE:To perform maintenance work of a platen roller or replace the same easily by supporting a platen roller unit detachably to a pair of notched parts of a bearing of a frame unit at opposite ends in the axial direction, and connecting the platen roller unit in an engageable manner to a driving unit when the platen roller unit is attached/detached. CONSTITUTION:A U-shaped notched part 21 is formed approximately at the central part of a side frame 2. Moreover, another U-shaped notched part is formed approximately at the central part of the other side frame 1. A platen roller unit 5 is detachably supported by pressing both ends of a rotary shaft 6 of the platen roller unit into these notched parts. The driving force is transmitted to the rotary shaft 6 of a platen roller 7 via a transmission gear 13 in the same direction as the falling direction of the rotary shaft 6, so that the rotary shaft 6 is prevented from being easily separated from the platen roller unit. A head cover 16 and a thermal head unit 15 are linked with each other. Therefore, when the head cover 16 is opened, the thermal head unit 15 is consequently rotated to be separated from the platen roller 7. Accordingly, it becomes considerably easy to attach or detach the platen roller 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a small-sized line thermal printer, and particularly to a structure for mounting a platen roller unit to a printer frame.

[Conventional technology]

Conventionally, small line thermal printers have been used as output terminals for measurement and analysis equipment, PO8 communication data terminal equipment, CRT hard copies, medical equipment, and the like. Small line thermal printer is 80mm fi 1mm, 112m
It has a size and shape that corresponds to recording paper width dimension standards such as m.

That is, the conventional line thermal printer includes a frame unit having a size and shape matching the width direction of the recording paper, a platen roller unit, a thermal head unit, and a head force bar arranged on the frame unit in parallel with the width direction. It consisted of a drive unit placed on the outside of the frame unit in the width direction and for rotating the platen roller unit.

[Problem that the invention seeks to solve]

However, in conventional small line thermal printers, the platen roller is intricately and integrally incorporated into the printer frame and cannot be easily removed. Therefore, there is a problem in that assembly is poor and inspection and maintenance of the platen roller is not easy.

[Means for solving problems]

In view of the above-mentioned problems of the conventional compact line thermal printer, an object of the present invention is to provide a compact line thermal printer having a structure that allows easy inspection, maintenance, or replacement of the platen roller.

In order to achieve the above object, in the small line thermal printer according to the present invention, the frame unit has a pair of bearing notches on both side surfaces spaced apart in the width direction of the recording paper, and the platen roller unit has a It is removably supported by a pair of bearing notches of the frame unit at both ends in the direction, and is connected to the drive unit so that it can be engaged and separated when the platen roller unit is installed or removed.

Preferably, a thermal head unit disposed facing the platen roller unit and a head cover disposed to cover the thermal head unit are mounted so as to be openable and closable relative to the frame unit in conjunction with each other, and in their open state, the platen The roller unit is configured to be detachable.

More preferably, the platen roller unit includes a rotating shaft, a platen roller formed around the rotating shaft, a shaft cylinder mounted on both ends of the rotating shaft and arranged in contact with each of a pair of bearing notches of the frame unit, and a rotating shaft. It has a configuration in which a drive gear that is locked to one end of the shaft and a head-up lever that is slidably engaged to the other end of the rotation shaft are integrally coupled.

More preferably, the drive unit has a transmission gear that directly engages with the drive gear of the platen roller unit, and the rotation direction of the transmission gear is such that the direction of power transmitted to the platen roller unit is directed toward the shaft support surface of the bearing notch. is set to
The platen roller unit is prevented from easily coming off from the bearing notch.

[For production]

According to the present invention, the platen roller unit configured by integrally joining a plurality of parts has the following functions at both ends in the axial direction:
Since the platen roller unit is removably supported by a pair of bearing notches formed in the frame unit and is connected to the drive unit so that it can be engaged and separated when it is installed or removed, the platen roller unit can be attached to the printer frame very easily. In addition to being easy to install, the platen roller unit can be easily maintained, inspected, or replaced by opening the thermal head unit and head cover as necessary.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a compact line thermal printer according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of a line thermal printer. As shown in the figure, the frame unit is designed to meet recording paper width standards (60mm, 80mm).
A pair of side frames 1 and 2 are arranged opposite to each other and are spaced apart from each other according to the width of the paper (mm, 112 mm, etc.), a recording paper guide frame 3 fixed between the pair of side frames 1 and 2, and a pair of side frames 1. and a frame shaft 4 that is locked between the two.

A U-shaped bearing notch is formed approximately at the center of the pair of side frames 1 and 2, and a platen roller unit 5 is removably pivotally supported in the bearing notch. The platen roller unit 5 includes a rotating shaft 6, a platen roller 7 formed around the rotating shaft 6, a drive gear 8 coaxially fixed to one end of the rotating shaft 6, and a drive gear 8 fixed to the other end of the rotating shaft 6. It consists of a head-up lever 9 that is slidably locked. The platen roller unit 5 obtained by integrally combining these components is removably assembled into the pair of side frames 1 and 2, so that assembly is extremely easy.

A drive unit IO for rotationally driving the platen roller unit 5 is detachably attached to the outer surface of one side frame 1. The drive unit 10 includes a step motor 11 and a wheel train mechanism 1 for transmitting the power of the step motor to the drive m'rts of the platen roller unit 5.
2. A transmission gear 13, which is located at the final stage of the wheel train mechanism 12 and directly engages with the drive gear 8, is arranged so as to be separable from the drive gear 8. These components of the drive unit are mounted on the motor frame 14 and are separably locked to the side frame 1.

A thermal head unit 15 is arranged opposite the platen roller unit 5. The thermal head unit 15 is detachably and swingably locked to the frame shaft 4. Furthermore, thermal head unit 1
The head force / (-16 is arranged so as to cover the frame shaft 4. The head cover 16 is rotatably supported on the frame shaft 4 and performs opening and closing operations.When the head cover 16 is in the closed state, a pair of screws 17 and t8, it is temporarily fixed to each of the pair of side frames 1 and 2.

FIG. 2 is a right side view of the line thermal printer shown in FIG. 1. As shown, the thermal head unit 15
is pivotally supported by the frame shaft 4, and the head cover 18 is also pivotally supported by the frame shaft 4. Moreover, the thermal head unit 15 and helad cover
16 are interlocked with each other, and when the head cover 16 is opened by loosening the screw 18, the thermal head unit 15 is also opened in the same direction as shown by the dashed line. Therefore, in this state, the thermal head unit 15 is retracted from the platen roller 6, and the platen roller unit 5 can be easily attached to and detached from the pair of side frames 1 and 2. In addition, maintenance, inspection, or replacement can be easily performed.

FIG. 3 is a schematic diagram showing the configuration and assembled state of the platen roller unit. As shown in the figure, the platen roller unit 5 includes a rotating shaft 6, a platen roller 7 formed around the rotating shaft 6, a drive gear 8 coaxially fixed to one end of the rotating shaft 6, and a rotating shaft 6. It has a configuration in which a head-up lever 9 is coaxially and slidably locked to the other end. The head up lever 9 is unrelated to the operation of the platen roller unit 5, and is in contact with a thermal head unit 15 (not shown), and by operating the head up lever 9, the thermal head unit 5 is moved relative to the platen roller unit 5. It is selectively set to either the pressure contact position or the non-pressure contact position. Further, shaft cylinders 19 and 20 are attached to both ends of the rotating shaft 6, respectively, and the platen roller unit 5 is connected to the bearing notches formed in each of the side frames 1 and 2 via the shaft cylinders 19 and 20. Pivotally supported.

A drive gear 8 fixed to one end of the rotating shaft 6 is engaged with a transmission gear t3 at the final stage of a wheel train connected to the rotating shaft of the step motor 11. Since the drive unit and the platen roller unit 5 are thus connected by the engagement between the gears, it is extremely easy to attach and separate the drive unit and the platen roller unit. Also, platen roller unit 5
Since they are simply dropped into the bearing notches formed in the side frames 1 and 2 from above, it cannot be said that there is a possibility that they may come off. Therefore, the rotational direction of the transmission gear I3 that engages with the drive gear 8 of the platen roller unit 5 is selected so that the direction of action of the transmitted power of the step motor coincides with the direction of dropping.

FIG. 4 is a sectional view of the line thermal printer taken along the line A--A shown in FIG. The mounting structure and operation of the platen roller unit 5, which constitutes the main part of the present invention, will be explained in detail with reference to FIG. As shown in the figure, a U-shaped bearing notch 21 is formed approximately in the center of the side frame 2.

Although not shown, a U-shaped bearing notch is also formed corresponding to the substantially central portion of the other side frame 1. The rotating shaft 6 of the platen roller unit is connected to these bearing notches.
By dropping both ends of the platen roller unit 5
is removably supported. In reality, the end of the rotating shaft 6 is supported by a notched bearing 21 via a shaft cylinder 20 that serves as a bearing. The U-shaped bearing notch 21 is formed at an angle of 0 to 15 degrees from the vertical direction. This is to improve the ease of assembling the platen roller unit and to prevent it from coming off easily.

A recording paper guide frame 3 is arranged below the platen roller 7 assembled in this manner.

The recording paper guide frame 3 has a first guide surface portion 22 that defines a so-called curl bus (indicated by arrow C) for the platen roller 7, and a first guide surface portion 22 that defines a so-called straight bus (indicated by arrow S) for the platen roller 7. A second guide surface portion 23 is provided. The recording paper fed along the curl bus or straight bus is pressed between the platen roller 7 and the thermal head unit 15, and after line printing is performed, it passes through the discharge bus (indicated by an arrow) and is sent to the outside. is discharged. In order to discharge the recording paper, the platen roller 7 needs to rotate counterclockwise as shown by arrow R. In order to rotate the platen roller 7 counterclockwise, it is necessary to rotate the transmission gear 13 (not shown) of the drive unit clockwise.

In this case, by arranging the transmission gear 13 on the left side of the platen roller 7 in the drawing, the power transmitted to the rotation shaft 6 of the platen roller through the transmission gear 13 coincides with the direction in which the rotation shaft 6 of the platen roller drops. This prevents the rotating shaft 6 from easily coming off. That is, the position and rotation direction of the transmission gear are set so that the direction of the power transmitted to the rotating shaft 6 is directed toward the shaft support surface 24 of the bearing notch 21.

As mentioned above, the head cover 16 is rotatably secured to the frame beam 4, and the thermal head unit 15
are rotatably and detachably attached to the same frame beam 4. The head cover 16 and the thermal head unit I5 are interlocked with each other, and when the head cover 16 is opened, the thermal head unit 15 also rotates and is retracted from the platen roller 7.

A roll-in prevention member 25 is attached to the paddle cover 16 above the platen roller 7. This entrainment prevention member 25 defines an ejection bus indicated by an arrow, and prevents the ejected recording paper from being reeled in by the platen roller. The entanglement prevention member 25 is the head cover 16
As it is evacuated from the platen roller 7 at the same time as opening,
Unlike the conventional method, the platen roller 7 can be attached and detached very easily.

〔Effect of the invention〕

As explained above, according to the present invention, the platen roller unit is pivotally supported by falling into the U-shaped bearing notches formed in the pair of side frames, so it is not only easy to assemble. Since it can be easily removed, maintenance, inspection and replacement of the platen roller unit is facilitated. In addition, by appropriately setting the rotational direction of the drive unit's wheel train mechanism, the direction of action of the power transmitted to the platen roller matches the direction in which the platen roller unit is lowered, so that the platen roller does not easily float up. I'm doing it like that. Furthermore, in the line thermal printer according to the present invention, since the head cover and the thermal head unit are configured to open and retreat from the platen roller in conjunction with each other, the platen roller unit can be attached and detached very easily.

[Brief explanation of drawings]

Fig. 1 is a front view of the line thermal printer, Fig. 2 is a side view of the line thermal printer, Fig. 3 is a schematic diagram of the platen roller unit incorporated in the line thermal printer, and Fig. 4 is the A- FIG. 2 is a cross-sectional view of the line thermal printer taken along line A. 1... Side frame 2... Side frame 3... Recording paper guide frame 4... Frame shaft 5... Platen roller unit 6... Rotating shaft 7... Platen roller 8... Drive Gear 9...Head up lever IO...Drive unit 13...Transmission gear 15...Thermal head unit 1B...Head force t<-19...Shaft tube 20...Shaft tube 21.・Bearing notch 25 ・Entrapment prevention member Applicant Seiko Electronics Co., Ltd. Agent

Claims (1)

[Claims] 1. A frame unit having dimensions matching the width direction of recording paper, a platen roller unit, a thermal head unit, and a head cover disposed on the frame unit in parallel with the width direction; In a line thermal printer, the frame unit has a pair of bearing notches on both side surfaces spaced apart from each other in the width direction, and the frame unit has a pair of bearing notches on both sides spaced apart in the width direction, and a drive unit for rotating the platen roller unit is arranged on the outside in the width direction. A line thermal printer characterized in that the unit is removably supported by the pair of bearing notches at both ends in the width direction, and is connected to the drive unit so that it can be engaged and separated when the unit is installed or removed. 2. The line thermal printer according to claim 1, wherein the thermal head unit and the head cover are mounted on the frame unit so as to be openable and closable in conjunction with each other, and the platen roller unit is attached and detached in the open state. 3. The platen roller unit is equipped with a gear at one end in the width direction, and the drive unit has a transmission gear that directly engages with the gear. The line thermal printer according to claim 1, wherein the line thermal printer is set to face the shaft support surface of the notch. 4. The platen roller unit includes a rotating shaft, a platen roller formed around the rotating shaft, a shaft cylinder attached to both ends of the rotating shaft and arranged in contact with each of a pair of bearing notches, and one end of the rotating shaft. 2. The line thermal printer according to claim 1, further comprising a gear that is engaged with the rotating shaft, and a head-up lever that is slidably engaged with the other end of the rotating shaft. 5. The head cover is provided with a member along the width direction to prevent the ejected recording paper from being caught in the platen roller unit, and when the head cover is open, the member is retracted from the platen roller unit. 3. The line thermal printer according to claim 2, wherein the line thermal printer can be easily attached and detached.