Label separating device in label printer

Abstract: According to the present invention, there is used a conveyance roller for the conveyance of a pasteboard (11a) with labels (11b); a separating member (14) is disposed on a downstream side from a pasteboard conveyance path with respect to a printing head (13) which holds the pasteboard with labels between the same and a platen (12), and in a position close to the printing head (13); and a pinch roller (16) is provided for holding between the same and the conveyance roller (12) the pasteboard portion which has been bent and separated from a label after printing by the separating member. The conveyance of the pasteboard with labels for printing and the conveyance of the pasteboard for label separating can be done at a time by driving either the conveyance roller (12) or the pinch roller (16).

Description: FIELD OF THE INVENTION AND RELATED ART STATEMENT The present invention relates to a label printer for printing required matters on a label stuck on a paper backing strip and then separating the printed label from the backing strip. Particularly, the present invention is concerned with a label separating device for separating a label from a paper backing strip. According to a label printer known to the applicant, required matters are printed on each label stuck on a backing strip and then the printed label is separated from the backing strip. In a label printer of this type using an elongated backing strip, means for conveying the backing strip in printing and means for conveying the backing strip to separate the printed label from the backing strip are independently provided. An example of such a device will be described below with reference to Figs. 1 and 2. A backing strip 1 with labels, or an elongated backing strip 1a with plural labels 1b stuck thereon is used. The backing strip 1 with labels is sandwiched between a platen 2 and a thermal head 3 while being guided along a predetermined guide path. On a downstream side of a backing strip conveyance path with respect to the platen 2 and the thermal head 3, there is provided a separating plate 4. Further, a separating roller 5 is provided under the platen 2 in the same axial direction, and a pinch roller 6 is held in pressure contact with the separating roller 5 so as to be movable away from the roller 5. Dedicated driving units (not shown) are connected to the platen 2 and the separating roller 5, respectively. In the label printer of the above construction, the backing strip 1a is drawn out in the conveyance path downstream from the separating plate 4 and is held between the separating roller 5 and the pinch roller 6. More specifically, the pinch roller 6 is moved away from the separating roller 5, and then the backing strip 1a is inserted between both rollers, so that the pinch roller 6 is again brought into pressure contact with the separating roller 5. The platen 2 is turned in synchronism with line-by-line printing for each label 1b by the thermal head 3, whereby the printing for the label 1b and the conveyance of the backing strip 1 with labels are performed simultaneously. At this time, the separating roller 5 also rotates and pulls the backing strip 1a without any sagging. Consequently, on the separating plate 4, the backing strip 1 with printed labels is bent at an acute angle, whereby the printed label 1b is separated from the backing strip 1a and is issued from an issuance port (not shown). The platen 2 as a means for conveying the backing strip 1 with labels is constituted separately from the separating plate 4, separating roller 5 and pinch roller 6 as means for separating each printed label 1b from the backing strip 1a. Consequently, the number of components is increased, the manufacture of the device is complicated, and a large space is required, thus resulting in increased size of the entire device. Further, since the separate driving units are used for the platen 2 and the separating roller 5, discrepancy is apt to occur between a conveyance speed for the backing strip 1a by the platen 2 and that by the separating roller 5. Once there occurs such discrepancy, the normal separation of the label 1b on the separating plate 4 may become impossible, or the normal printing may become no longer feasible due to change in the conveyance speed for the pasteboard 1a by the platen 2. Another known device, as disclosed in German Specification No. 2816161 comprises a conveyor roller for the conveyance of a paper backing strip with labels which is guided along a predetermined path; a printing head and a platen forming a printing nip for printing, a separating member disposed on the paper backing strip conveyance path downstream with respect to a printing head which holds the paper backing strip with labels between the same and the platen, the separating member being in a position close to the printing head; and a second roller for drawing away together with said platen the paper backing strip portion which has been bent and separated from a label after printing by said separating member, whereby the predetermined path of the paper backing strip passes through the printing nip between the printing head and the platen, over the separating member and between the platen and the pinch roller. This device suffers from the problem that owing to the high slip nature of the backing strip which is necessary to enable the labels to be removed easily, the drive system can suffer from slippage. The present invention overcomes this problem by being characterised in that said second roller is a pinch roller which pinches the backing strip against the platen thus forming a conveying nip between the second roller and the platen, that the pinch roller is mounted on a rotatable frame whereby the frame is urged by a coiled torsion spring so that the pinch roller is kept in contact with the conveyance roller, and that the printing nip, the conveying nip and the shaft for the pinch roller are in vertical alignment. The invention has the further benefits of compactness. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an entire perspective view of a label separating device known to the applicant; Fig. 2 is a side view of the label separating device of Fig. 1; Fig. 3 is an entire perspective view of a label separating device in an embodiment according to the present invention; and Fig. 4 is a side view of the label separating device. DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment according to the present invention will now be described with reference to Figs. 3 and 4. First, there is provided a paper backing strip with labels 11 comprising an elongated backing strip 11a and a plurality of labels 11b which are stuck on the backing strip 11a at predetermined intervals. The backing strip 11 with labels is guided and held between a platen 12 and a thermal head 13 serving as a printing head. More specifically, the platen 12 is formed of a cylindrical member, and the whole thereof is mounted to a label printer body (not shown) in such a manner as to rotate about a platen shaft 12a as the central shaft thereof. A driving unit (not shown) for driving and rotating the platen 12 is connected to the platen shaft 12a. Therefore, the platen 12 fulfills not only the function of the platen itself required for printing but also the function as a conveyance roller for conveying the backing strip 11 with labels. The thermal head 13 is held in pressure contact with the platen 12 in a contacted state of a heat generating portion 13a thereof with the platen 12. In the conveyance path of the backing strip 11 with labels, a separating member 14 formed of a plate member is disposed near and downstream from the platen 12 and the thermal head 13. Under the platen 12 is provided a pinch roller 16 so as to be movable into contact with and away from the platen. A roller shaft 16a of the pinch roller 16 is mounted to a frame 20, whereby the pinch roller 16 is held rotatably. The frame 20 is mounted to the label printer body rotatably about a support shaft 21 so that the roller shaft 16a of the pinch roller 16 is parallel to the platen shaft 12a of the platen 12. Around the support shaft 21 is wound a coiled torsion spring 22, one end of which is fixed to the label printer body while the other end of which is fixed to the frame 20. The frame 20 is urged by the torsion spring 22 so that the pinch roller 16 is kept in contact with the platen 12. Further, the frame 20 is provided with a handle 23 in a position below the separating member 14. The heat generating portion 13a of the thermal head 13, the platen shaft 12a of the platen 12 and the roller shaft 16a of the pinch roller 16 are substantially aligned on a vertical line. In using the label separating device of the above construction, first the backing strip 11a which has been guided between the platen 12 and the thermal head 13 and drawn out from the separating member 14 is inserted between the platen 12 and the pinch roller 16. In more particular terms, the frame 20 is turned downwards with the handle 23 to disengage the pinch roller 16 from the platen 12. In this state, the backing strip 11a is inserted between the platen 12 and the pinch roller 16. Upon release of the handle 23, the frame 20 returns to its original position under the biasing force of the torsion spring 22, so that the pinch roller 16 comes into abutment with the platen 12. At this time, tension is applied to the backing strip 11a. Then, the platen 12 is rotated by the driving unit connected thereto, whereby the backing strip 11 with labels is conveyed, and predetermined matters are printed on the label 11a by the thermal head 13. At the same time, the backing strip 11a inserted between the platen 12 and the pinch roller 16 is also conveyed, so that tension is applied to the backing strip 11a. Therefore, when the backing strip 11 with labels after printing arrives at the separating member 14, only the backing strip 11a is bent at an acute angle along the separating member, while the printed label 11b is separated from the backing strip 11a and is issued from an issuance port (not shown). Thus, in this embodiment, both the conveyance of the backing strip 11 with labels for printing each label 11b and the conveyance of the backing strip 11a for separating the label 11b after printing are performed by the rotation of the platen 12. Thus, the parts required for the means to convey the backing strip 11 with labels and those required for the means to separate the label 11b can be used in common. Consequently, the number of the whole parts of the label printer decreases, thus contributing to the reduction of parts cost; besides, the manufacture of the entire label printer becomes easier, thus leading to shortening of the assembling time and reduction of the manufacturing cost; and further, the smaller space occupied by the label separating device contributes to the reduction in size of the entire label printer. Additionally, since the peripheral speed of the platen 12 is constant at any part of the peripheral surface of the platen 12, the conveyance speed of the backing strip 11 with labels passing the heat generating portion 13a of the thermal head 13 and the conveyance speed of the backing strip 11a after separation of a printed label 11b become equal to each other, that is, no discrepancy will occur between these two speeds. Consequently, defective separation of the label 11b and defective printing for the label 11b can be surely prevented. The separating member 14 is disposed near the thermal head 13 and the roller shaft 16a of the pinch roller 16 is disposed in a position substantially opposed to the heat generating portion 13a of the thermal head 13. In such a positional relation of the components, the backing strip 11a is wound around about a quarter of the peripheral surface of the platen 12. Consequently, the frictional resistance between the platen 12 and the backing strip 11a is increased to ensure the conveyance of the backing strip 11a by the platen 12, and defective separation of the label 11b can be prevented. Besides, since the handle 23 of the frame 20 is positioned near the issuance port of the label 11b, the engaging and disengaging operation for the pinch roller 16 with respect to the platen 12 can be done more easily. Although in this embodiment a driving unit is connected to the platen 12, the platen 12 may be of a freely rotating structure and the driving unit may be connected to the pinch roller 16.

Claims: A label printer comprising: a conveyor roller (12) for the conveyance of a paper backing strip with labels which is guided along a predetermined path; a printing head (13) and a platen (12), wherein the platen (12) is formed by the conveyor roller (12) and forms a printing nip for printing; a separating member (14) disposed on the paper backing strip conveyance path downstream with respect to the printing head (13) which holds the paper backing strip with labels between the same and the platen, the separating member (14) being in a position close to the printing head (13); and a second roller (16) for drawing away together with said platen the paper backing strip portion which has been bent and separated from a label after printing by said separating member, whereby the predetermined path of the paper backing strip (11a) passes through the printing nip between the printing head (13) and the platen (12), over the separating member (14) and between the platen (12) and the second roller (16), characterised in that said second roller (16) is a pinch roller which pinches the backing strip against the platen (12) thus forming a conveying nip between the second roller and the platen, that the pinch roller (16) is mounted on a rotatable frame (20) urged by a coiled torsion spring (22) so that the second roller is kept in contact with the conveyance roller (12), and that the printing nip, the conveying nip and the shaft for the pinch roller are in vertical alignment. A label separating device according to claim 1 characterised in that said rotatable frame (20) is pivoted about an axis (21) which is offset relative to a line through the printing nip, the conveying nip and the pinch roller shaft and comprises a handle means (23) which enables the frame (20) to be opened against said coiled torsion spring (22) to release pressure at said conveying nip.

Inventors: FUSHIMI KAZUHIRO, SUGIMOTO KAZUAKI, TASHIRO TAKESHI, FUSHIMI, KAZUHIRO, SUGIMOTO, KAZUAKI, TASHIRO, TAKESHI
Applicants: TOKYO ELECTRIC CO LTD, KABUSHIKI KAISHA TEC
Application year: 1990
Main classification: B65C11
IPC codes: B65C11, B41J5, B65C9, B65H41