JPH0788101B2 - Line thermal printer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line thermal printer used for electronic registers and the like.

2. Description of the Related Art In recent years, a line thermal printer has been developed as a low-noise, high-speed printer. In this line thermal printer, a line thermal head in which a large number of heating elements are arranged in an array is arranged to face a platen such as a cylinder, and paper is sandwiched between the line thermal head and the platen for printing. is there. Although such line thermal printers are used in various devices, electronic registers require multiple prints of different types such as receipts, journals, slips, etc. ing. Therefore, reduction in size and weight of the electronic register is hindered. Therefore, as a solution to such a problem, as illustrated in FIG. 5, two one-way clutches 2 and 3 are attached to a common shaft 1 and two one-way clutches are rotated by forward / reverse rotation of one motor 4. Feed rollers 5,6
There exists a sheet conveying device 7 that drives one of the two. In such a sheet transporting device 7, one of the two feed rollers 5 and 6 can be selected and driven without providing a switching means. Therefore, by arranging long line heads (not shown) facing these feed rollers 5 and 6, it is possible to obtain a printer that separately issues two types of prints.

Problems to be Solved by the Invention Since the above-described sheet transporting device 7 can form a printer that issues two kinds of prints separately, it is possible to reduce the size and weight of an electronic register or the like. . However, since the one-way clutches 2 and 3 generate a lot of noise during operation and have poor durability, and are expensive parts, such a device is not preferable in practical use. Moreover,
Since the one-way clutches 2 and 3 are provided on the sides of the feed rollers 5 and 6, a gap is required between the feed rollers 5 and 6, and the lateral width of the device is increased.

Means for Solving the Problem Providing a plurality of cylindrical platens arranged on the same axial center and each conveying a sheet, providing one line thermal head opposite to these platens, and providing one drive source It consists of a connected sun gear, a planetary gear that meshes with this sun gear and oscillates with its forward and reverse rotation torque, and at least one transmission gear that meshes selectively with the planetary gear via an intermediate gear. Driving force transmission means is provided, and transmission gears of the driving force transmission means are respectively connected to two of the plurality of platens.

Action A plurality of cylindrical platens arranged on the same axis and each carrying a sheet are provided, one line thermal head is provided opposite to these platens, and a sun gear connected to one drive source , A driving force transmitting means including a planetary gear that meshes with the sun gear and oscillates by the forward and reverse rotation torque, and at least one transmission gear that includes two transmission gears that selectively mesh with the planetary gear via an intermediate gear , By connecting the transmission gears of the driving force transmission means to two of the plurality of platens respectively, one of the two platens can be selected by the forward and reverse rotation of one drive source without providing a switching means. Can be rotated.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 4. In this embodiment, the line thermal printer 8 for electronic register is assumed, and three cylindrical platens 9 to 11 having the same diameter for slips, receipts and journals are continuously arranged on the same axis. . And these platens 9
A line thermal head 13 that is swingable by a cam mechanism 12 is arranged to face each other. In the line thermal printer 8, the stepping motor 14 which is one driving source is connected to the two platens 9 and 10 through the driving force transmitting means 15. Therefore, the structure of the driving force transmitting means 15 will be described. First, an arm 19 is rotatably attached to a shaft 18 of a sun gear 17 connected to the stepping motor 14 via a gear 16.
A planetary gear 20 attached to the tip of the gear meshes with the sun gear 17. On the other hand, the platen shaft 21 to which the platen 9 is fixed has a hollow inside, and the platen shaft 22 to which the second platen 10 is fixed is inserted therein. The planetary gear 20 has a transmission gear 23 directly connected to the platen shaft 21 when the arm 19 swings, and an intermediate gear connected to the platen shaft 22 via a transmission gear 24 and an intermediate gear 25. It is adapted to mesh with one side of the gear 26. In the line thermal printer 8, the platen 11 for the journal is also separately connected with the driving device 29 including the stepping motor 27 and the gear mechanism 28. Further, in the line thermal printer 8, the roll papers 30 to 32 are rotatably supported at positions facing the platens 9 to 11, respectively.

With such a configuration, in the line thermal printer 8, when the platen 9 is rotated to issue a slip, the stepping motor 14 is rotated clockwise in FIG. Then, the sun gear 17 rotates counterclockwise,
The arm 19 attached to the shaft 18 of the sun gear 17 swings upward. The planet gear 20 attached to the tip of the arm 19 is a transmission gear 23 directly connected to the platen 9.
Bite into. Therefore, the platen 9 is rotated by the driving force of the stepping motor 14, and the line thermal head
Printing is performed on the roll paper 30 for slips sequentially conveyed by 13.

On the other hand, when the platen 10 is rotated to issue a receipt, the stepping motor 14 is rotated counterclockwise in FIG. 2 to engage the planetary gear 20 with the intermediate gear 26.
Then, the intermediate gear 26 is moved to the platen 1 via the gears 24 and 25.
Since it is connected to 0, the driving force of the stepping motor 14 is transmitted to the platen 10. Here, in the line thermal printer 8, since the intermediate gears 25 and 26 are provided, the platens 9 and 10 can rotate in the same direction even when the stepping motor 14 rotates in the forward and reverse directions. The roll papers 30 and 31 can be easily installed, and the position of the issuing port (not shown) can be made common.

In the line thermal printer 8, the platen 11 is rotated by the driving device 29 when issuing a journal.

EFFECTS OF THE INVENTION The present invention is provided with a plurality of cylindrical platens arranged on the same axis as described above and each conveying a sheet, and provided with one line thermal head opposed to these platens. , A planetary gear that meshes with the sun gear and oscillates with its forward and reverse rotation torque, and at least one of two transmissions that selectively meshes with the planetary gear via an intermediate gear. By providing a driving force transmitting means composed of a gear and connecting the transmitting gears of the driving force transmitting means to two of the plurality of platens,
Since one of the two platens can be selectively rotated by forward / reverse rotation of a single drive source without providing a switching unit, a device for performing a plurality of prints such as electronic registers having different carry amounts. Since it is possible to contribute to size reduction and weight reduction of the platen, and it is not necessary to form a selective drive force transmission by a gear train and to provide a one-way clutch for each platen, it is possible to arrange a plurality of platens close to each other. It is possible to reduce the size of the device, and to obtain a device with low operating noise and high durability.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is an explanatory view of a driving force transmitting means, FIG. 3 is a vertical sectional front view of a main portion, FIG. 4 is a perspective view of the main portion, and FIG. It is a perspective view of a prior art example. 8 ... Line thermal printer, 9-11 ... Platen, 13 ...
Line thermal head, 14 ... Driving source, 15 ... Driving force transmitting means, 17 ... Sun gear, 20 ... Planetary gear, 23, 24 ... Transmission gear, 2
5,26 ... Intermediate gear

Claims (1)

[Claims] 1. A plurality of cylindrical platens, which are arranged on the same axis and each convey a sheet, are provided, and one line thermal head is provided opposite to these platens and is connected to one drive source. Drive force transmission consisting of a sun gear, a planetary gear that meshes with the sun gear and oscillates with forward and reverse rotation torque, and at least one transmission gear that is selectively meshed with the planetary gear through an intermediate gear And a transmission gear of the driving force transmission means is connected to two of the plurality of platens, respectively.