EP1323535A2

EP1323535A2 - Thermal printer

Info

Publication number: EP1323535A2
Application number: EP02258479A
Authority: EP
Inventors: Takumi c/o SII P & S Inc. Seino
Original assignee: SII P and S Inc
Current assignee: SII P and S Inc
Priority date: 2001-12-28
Filing date: 2002-12-09
Publication date: 2003-07-02
Anticipated expiration: 2022-12-09
Also published as: DE60203688T2; EP1323535B1; DE60203688D1; JP2003200624A; EP1323535A3; JP3734753B2

Abstract

To provide a thermal printer in which a planar area may be reduced when the printer is mounted on various information equipments.

The printer is composed of an operating piece (5d) formed by extending one end portion of a rotary shaft support portion (5a) of a lock arm (5) in a direction away from a platen roller (2) and a downwardly depressing means (slide type release lever L1, rotary type release lever L2) engaging with the operating piece for downwardly depressing this operating piece against a biasing force of a biasing means. There is provided a platen roller release means for releasing the engagement condition between the rotary shaft of the platen roller and the rotary shaft support portion of the lock arm member.

Description

The present invention relates to a miniature thermal printer mounted on a variety of portable information equipments or like and more particularly to a thermal printer in which a platen roller is detachably mounted.
A general conventional line dot type thermal printer is composed of a line thermal head and a platen roller assembled into a frame to face each other, a drive means therefor, a transport mechanism for transportation of thermal recording paper, and the like.
Meanwhile, there is a thermal printer in which in order to facilitate the operation for interposing a roll paper used as recording paper between the line thermal head and the platen roller, the platen roller is so structured as to be removed away from the frame.
Herewith, a structural example of a conventional thermal printer provided with a separating mechanism for a platen roller will now be described with reference to Figs. 5 to 7.
The thermal printer P2 shown in Figs. 5 and 6 is composed of a platen roller 102 pivotally supported to a frame 101, a head support member 103 provided with a thermal head H facing the platen roller 102, two coil springs 104 for giving a biasing force for depressing this head support member 103 to the platen roller 102, a lock arm member 105 for pivotally supporting both end portions 102A1 and 102A2 of a rotary shaft 102A of the platen roller 102, a motor M as a drive source, and a gear transmission mechanism G for transmitting a rotary drive force of the motor M to a driven gear 102B fixed to one end 102A2 of the platen roller 102.
The lock arm member 105 is formed substantially into a U-shape as a whole and is provided with a pair of hook-shaped rotary shaft support portions (latch portions) 105a for engaging with and dragging both end portions 102A1, 102A2 of the rotary shaft of the platen roller 102 so that the surface of the platen roller 102 is brought into pressing contact with the thermal head H side, a pair of arm portions 105b for leading the latch portions 105a to the back side of the head support member 103 through both sides of the head support member 103, and an elastic member support portion 105c arranged in the widthwise direction of the back side of the head support member 103 provided with arm portions 105b at both sides thereof for supporting the above-described coiled springs 104. Note that the lock arm member 105 is rotatably supported to both side surfaces of the frame 101.
Furthermore, a release lever portion L3 as an engagement release means for swinging on the platen roller side the lock arm member 105 per se so as to release the engagement between the latch portion 105a and both shaft ends 102a and 102b of the platen roller 102 is provided at an upper end portion of an elastic portion support portion 105c of the lock arm member 105.
As shown in, for example, Fig. 7, the thermal printer P2 with such a structure is mounted on an information terminal (for example, an information terminal by which a delivery man or the like may perform the payment by a card at the client site) E3.
The information terminal E3 is provided in a case body C3 with an input portion 200 constituted by, for example, a plurality of key buttons, a liquid crystal display portion 201, a card readout portion 202 for reading out data of a magnetic recording portion of a magnetic card, a recording paper receiving portion 203 for receiving a roll of recording paper R, a cover member 204 for pivotally supporting the platen roller 102, which may be opened and closed together with the platen roller 102, and the like.
Also, the release lever portion L3 of the thermal printer P2 is exposed outside through an opening portion 205 in an installation space S2 between the card readout portion 202 of the top surface of the case body C3 and the recording paper receiving portion 203.
Then, in this information terminal E3, when the recording paper R is replenished to the thermal printer P2 or there occurs the clog of the roll paper R, the release lever portion L3 is manipulated as indicated by an arrow A of Fig. 5(b) and Fig. 6(b) so that the engagement condition of the latch portion 105a of the lock arm member 105 and both end portions 102A1 and 102A2 of the rotary shaft of the platen roller 102 is released, and the platen roller 102 may be removed under the opened condition together with the cover member 204 as shown in Fig. 7.
Thus, the structure is advantageous in that it is possible to quickly and readily perform the removal work of the clogged paper or the replenishment work of the recording paper R.
However, due to the demand of the further miniaturization of the above-described portable information terminals, the thermal printer to be mounted on these terminals is also required to be further miniaturized or to have space-saving factor.
For example, also in the thus structured thermal printer P2, the motor M is arranged on the lower side of the frame 101 to thereby reduce an area on the top surface and to reduce a planar area of the case body C3 of the information terminal E3 to contribute to the miniaturization. However, in order to perform the further miniaturization, it is available to reduce the installation space S2 of the release lever portion L3 of the above-described platen roller 102.
In particular, in the thus structured information terminal E3, since the planar area for installing the card readout portion 202 is enlarged, it is effective to dispense with the release lever portion L3 arranged on the top surface to reduce the planar area.
In order to overcome the above-noted defects an object of this invention is to provide a thermal printer in which the planar area may be reduced when the printer is mounted on a variety of information equipments.
In order to attain the above-mentioned object, according to the present invention, there is provided a thermal printer including at least: a frame (1) having a pair of side wall portions arranged to face each other at a predetermined interval in a paper width direction; a head support member (3) rotatably supported by the pair of side wall portions for holding a line thermal head (H); a platen roller (2) having a circumferential surface to be brought into contact with the thermal head; a lock arm member (5) for rotatably supporting both end portions (2C, 2D) of a rotary shaft (2A) of the platen roller; a biasing means (coil springs 4) for imparting a biasing force for depressing the circumferential surface of the platen roller to the line thermal head side to a pair of hook-shaped, engageable and disengageable rotary shaft support portion (latch portions 5a) owned by the lock arm member; and a gear transmission mechanism (G) for transmitting a rotational drive force to a driven gear (gear portion 2B) fixed to one end of the platen roller, in which a platen roller separating means for releasing the engagement condition between the rotary shaft of the platen roller and the rotary shaft support portion of the lock arm is provided, the platen roller separating means composed of an operating piece (5d) formed by extending one end portion of the rotary shaft support portion of the lock arm in a direction away from the platen roller, and a downwardly depressing means (slide type release lever L1, rotary type release lever L2) engaging with the operating piece for downwardly depressing this operating piece against the biasing force of the biasing means.
Thus, since it is unnecessary to arrange upwardly the operating lever (release lever member) for separating the platen roller like in the prior art, it is possible to save the operating lever and the operating space therefor in the planer surface (top surface) of the information equipment when the printer is assembled into the various information equipments, which may reduce the planar area to contribute to the miniaturization. In the present invention, it is possible to arrange the above-described downwardly depressing means to the side wall portion or the like of the information equipment, which will not relatively obstruct the miniaturization.
Also, the downwardly depressing means may have a slide member mounted slidably along a slide groove formed and opened in one side wall portion of a box member for receiving the thermal printer and having an engagement portion engageable with the operating piece within the box member. Thus , it is possible to arrange the downwardly depressing means without obstructing the miniaturization of the information equipment to thereby make it possible to reduce the planar area.
Also, the downwardly depressing means may have: a rotary shaft arranged in parallel with the platen roller in the vicinity of the operating piece; an engagement member located at a shaft end of the rotary shaft and engaging with the operating piece in accordance with the rotation of the rotary shaft; and a lever member fixed to the rotary shaft for rotatably moving the rotary shaft. Thus, the degree of freedom of the arrangement position of the downwardly depressing means is enhanced to contribute to the miniaturization of the various information equipments and to make it possible to enhance the operationability.
Note that the lever member may have its upper end portion exposed to the outside through the slide groove opened and formed in an upper surface of the box member for receiving the thermal printer and is so constructed as to be operable from the outside of the box. Thus, it is possible to readily perform the removal operation of the platen roller from the outside of the box member (cover).
Also, the biasing means may be composed of an elastic member interposed between a beam portion of the lock arm member extended in a widthwise direction of the frame and a back surface portion of the line thermal head. Thus, it is possible to provide a thermal printer that may reduce the planar area with ease and at low cost by utilizing the structure of the existing thermal printers.
Embodiments of the present invention will now be described by way of further example only and with reference to the accompanying drawings, in which:-
Fig. 1 is a perspective view showing an embodiment of a thermal printer P1 to which the present invention is applied;
Fig. 2 is a side elevational cross-sectional view showing a schematic structure of the thermal printer P1;
Fig. 3(a) is a perspective view showing an example in which the thermal printer P1 is mounted on an information terminal and Fig. 3(b) is a schematic structural view of a part thereof;
Fig. 4 is a partially transparent perspective view showing an example in which the thermal printer P1 is mounted on an information equipment;
Fig. 5 is a perspective view showing a structure of a conventional thermal printer P2;
Fig. 6 is a side elevational cross-sectional view showing a schematic structure of the conventional thermal printer P2; and
Fig. 7 is a perspective view showing an example in which the conventional thermal printer P2 is mounted on an information equipment.
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings.
Fig. 1 is a perspective view showing an embodiment of a thermal printer P1 to which the present invention is applied. Fig. 2 is a side cross-sectional view showing a schematic structure of the thermal printer P1.
As shown in Figs. 1 and 2, the thermal printer P1 is composed of a frame 1 injection molded of plastic such as polycarbonate or the like and having a pair of side wall portions arranged to face each other through a predetermined interval in a paper width direction, a head support member 3 for holding a thermal head H having a plurality of heat generating elements, a lock arm member 5 for rotatably and detachably pivotally supporting a platen roller 2 by the pair of side wall portions of the frame 1, and a gear transmission mechanism G for transmitting a rotational drive force of the motor M to a driven gear 2B fixed to one end 2C of the platen roller 2.
The lock arm member 5 is formed substantially into a U-shape as a whole and is provided with: a pair of hook-shaped rotary shaft support portions (latch portions) 5a for engaging with both end portions 2C and 2D of the rotary shaft 2A of the platen roller 2 and dragging the surface of the platen roller 2 into pressing contact with the thermal head H side; a pair of arm portions 5b for leading the latch portions 5a backward of the head support member 3 through both sides of the head support member 3; and an elastic member support portion 5c arranged backward of the head support member 3 in the widthwise direction for supporting coil springs 4 and provided with arm portions 5b at both ends. Note that the lock arm member 5 is rotatably supported to both side surfaces of the frame 1.
Furthermore, a tip end portion of one of the arm portions 5b of the lock arm member 5 (on the end portion D side of the platen roller 2 in this embodiment) is extended and formed into an operating piece 5d.
This operating piece 5d is depressed downwardly by a slide type release lever L1 or a rotary type release lever L2 as a downwardly depressing means to be described later so that the engagement between both shaft ends 2C and 2D of the latch portions 5a and the platen roller 2 is released and the lock arm member 5 per se is swung to the platen roller side.
Namely, as shown in Figs. 1(a) and 1(b), the lock arm 5d of the lock arm member 5 is depressed downwardly; the platen roller 2, for example, is removed together with the cover member of the information equipment under the opened condition so that it is possible to readily and quickly perform the replenishment work of the recording paper and the removal work of the clogged paper.
Furthermore, in the thermal printer P1 according to this embodiment, since it is unnecessary to arrange the operating lever (the release lever member) for separating the platen roller 2 on the upper surface side of the information equipment like in the prior art, it is possible to save the operating lever and its operating space in the planer surface (top surface) of the information equipment when it is assembled into the various information equipments so that the planar area is reduced to contribute to the miniaturization. The slide type release lever L1 or the like as the downwardly depressing means may be arranged on the side wall portion or the like of the information equipment that will not relatively obstruct the miniaturization.
Hereby, an example in which the thermal printer P1 according to this embodiment is mounted on the information equipment will be described with reference to Figs. 3 and 4.
Fig. 3 shows an example in which the thermal printer P1 is mounted on a portable information terminal as a kind of information equipment (for example, an information terminal by which a delivery man or the like may perform the payment at a client site).
The information terminal E1 is provided in a case body C1 with an input portion 200 constituted by, for example, a plurality of key buttons, a liquid crystal display portion 201, a card readout portion 202 for reading out data of a magnetic recording portion of a magnetic card, a recording paper receiving portion 203 for receiving a roll of recording paper R, a cover member 204 for pivotally supporting the platen roller 2, which may be opened and closed together with the platen roller 2, and the like.
Also, the slide type release lever L1 is provided on the side surface (the right side surface in this embodiment) of the case body C1 for removing the platen roller 2 of the thermal printer P1. As shown in Fig. 3(b), the slide type release lever L1 is provided with an operating piece 5d of the lock arm member 5 of the thermal printer P1, a convex portion L1a engaged from above with the operating piece 5d of the lock arm member 5 of the thermal printer P1, and a slippage preventing portion L1b for finger tip hook during the slide and is slidably supported in the slide groove 300 opened on the side surface of the case body C1 so that a slippage preventing portion L1b side may be exposed outside of the case body C1.
Then, the slide type release lever L1 with such a structure is manipulated to be depressed downwardly so that the convex portion L1a is engaged with the operating piece 5d of the lock arm member 5 of the thermal printer P1 to be depressed downwardly. As shown in Figs. 1(b) and 2(b), the engagement between the latch portions 5a and both shaft ends 2C and 2D of the platen roller 2 is released. As shown in Fig. 3(a), the platen roller 2 may be removed together with the cover member 204 under the opened condition.
Thus, it possible to arrange the slide type release lever L1 as the downwardly depressing means without obstructing the miniaturization of the information equipment to make it possible to reduce the planar area. Namely, comparing the information terminal E3 shown in above-described Fig. 7 with the information terminal E1 shown in Fig. 3(a), it was necessary to provide the installation space S2 having a relatively large area in order to provide the release lever portion L3 between the card readout portion 202 on the upper side of the information terminal E3 and the recording paper receiving portion 203. However, in the information equipment E1 according to this embodiment, since it is unnecessary to provide the release lever on the top surface side, it is possible to reduce the space S1 between the card readout portion 202 on the top surface side of the information equipment E3 and the recording paper receiving portion 203, as a result of which it is possible to further reduce the planer area of the information terminal E1 than that of the conventional information terminal E3 and to contribute to the further miniaturization.
Subsequently, with reference to Fig. 4, an example in which a thermal printer P1 is mounted on an information equipment E2 provided with a rotary type release lever L2 will be described.
The information equipment E2 is provided in the case body C2 at least with a receiving portion 30 of the thermal printer P1 and the recording paper R and a cover portion 40 for pivotally supporting the platen roller 2 of the thermal printer P1, which may be opened and closed together with the platen roller 2. A rotary type release lever L2 is composed of a rotary shaft 10 rotatably supported in parallel with the platen roller 2 and the like on the side where the operating piece 5d of the lock arm member 5 of the thermal printer P1 is located, an engagement piece 10a fixed at one end of the rotary shaft 10 and engageable from above with the operating piece 5d of the lock arm member 5, and a lever member 20 fixed in the middle of the rotary shaft 10 and rotatably moving the rotary shaft 10 the platen roller 2 side. This lever member 20 is adapted to be exposed to the outside through an operating port 40a opened in the outer wall of the cover portion 40. Then, the lever member 20 is rotated and operated upwardly manually from the outside of the cover portion 40 so that the engagement piece 10a fixed to the rotary shaft 10 depresses the operating piece 5d of the lock arm member 5 of the thermal printer P1 downwardly, the engagement between both shaft ends 2C and 2D of the platen roller 2 and the latch portions 5a is released and the platen roller 2 may be removed together with the cover member 40 under the opened condition.
Thus, in comparison with the conventional case, the degree of freedom of the arrangement position of the release lever L2 is enhanced, and it is possible to contribute to the miniaturization of the various information equipments and to enhance the operationability.
The invention made by the present inventors has been described specifically based upon the embodiments. However, the present invention is not limited to the above-described embodiments and it is possible to effect change within the scope of the claims.
For example, in the foregoing embodiment, the case where the thermal printer P1 is mounted on the portable information equipment has been described. However, the invention is not limited to this and may be applied to the case where the printer is mounted on various information equipments such as a facsimile machine, a note type personal computer and the like, which may contribute to the miniaturization of these various information equipments.
As described above, since a thermal printer includes at least: a frame having a pair of side wall portions arranged to face each other at a predetermined interval in a paper width direction; a head support member rotatably supported by the pair of side wall portions for holding a line thermal head; a platen roller having a circumferential surface brought into contact with the line thermal head; a lock arm member for rotatably supporting both end portions of a rotary shaft of the platen roller; a biasing means for imparting a biasing force for depressing the circumferential surface of the platen roller to the line thermal head side to a pair of hook-shaped, engageable and disengageable rotary shaft support portion owned by the lock arm member; and a gear transmission mechanism for transmitting a rotational drive force to a driven gear fixed to one end of the platen roller, and is characterized in that: a platen roller separating means for releasing the engagement condition between the rotary shaft of the platen roller and the rotary shaft support portion of the lock arm is composed of an operating piece formed by extending one end portion of the rotary shaft support portion of the lock arm in a direction away from the platen roller, and a downwardly depressing means engaging with the operating piece for downwardly depressing this operating piece against the biasing force of the biasing means, it is unnecessary to arrange upwardly the operating lever for separating the platen roller like in the prior art. Thus, when the printer is assembled into various information equipments, it is possible to save the operating lever and the operating space therefor in the planar surface (top surface) of the information equipments, which may reduce the planar area to contribute to the miniaturization

Claims

A thermal printer comprising:

a frame having a pair of side wall portions arranged to face each other at a predetermined interval in a paper width direction;

a head support member rotatably supported by the pair of side wall portions for holding a line thermal head;

a platen roller having a circumferential surface brought into contact with the line thermal head;

a lock arm member for rotatably supporting both end portions of a rotary shaft of the platen roller;

a biasing means for imparting a biasing force for depressing the circumferential surface of the platen roller to the line thermal head side to a pair of hook-shaped, engageable and disengageable rotary shaft support portion owned by the lock arm member;

a gear transmission mechanism for transmitting a rotational drive force to a driven gear fixed to one end of the platen roller;

an operating piece formed by extending one end portion of the rotary shaft support portion of the lock arm in a direction away from the platen roller;

a downwardly depressing means engaging with the operating piece for downwardly depressing this operating piece against the biasing force of the biasing means; and

a platen roller separating means for releasing the engagement condition between the rotary shaft of the platen roller and the rotary shaft support portion of the lock arm.
The thermal printer according to claim 1, wherein the downwardly depressing means has a slide member mounted slidably along a slide groove formed and opened in one side wall portion of a box member for receiving the thermal printer and having an engagement portion engageable with the operating piece within the box member.
The thermal printer according to claim 1, wherein the downwardly depressing means comprising:

a rotary shaft arranged in parallel with said platen roller in the vicinity of said operating piece;

an engagement member located at a shaft end of the rotary shaft and engaging with said operating piece in accordance with the rotation of the rotary shaft; and

a lever member fixed to the rotary shaft for rotatably moving the rotary shaft.
The thermal printer according to claim 3, wherein the lever member has its upper end portion exposed to the outside through the slide groove opened and formed in an upper surface of the box member for receiving the thermal printer and is so structured as to be operable from the outside of the box.
The thermal printer according to any one of claim 1 to claim 4, wherein the biasing means comprising:

an elastic member interposed between a beam portion of the lock arm member extended in a widthwise direction of the frame and a back surface portion of the line thermal head.