JPH0155114B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to the structure of a non-impact type printing device, and in particular, to a non-impact type printing device in which a platen holder and a paper feed pinch roller are pivotally supported so as to be able to swing around the same axis. This invention relates to structural improvements to impact printing devices.

(Prior art) Printing devices (printers) used for input/output devices of various electronic devices including typewriters include impact type printing devices such as ordinary typewriters and wire dot type printing devices, and thermal transfer type printing devices. There are two types of printers: thermal printers and non-impact printers such as inkjet printers.

FIGS. 1 and 2 are diagrams illustrating a schematic configuration of the non-impact type printing device.

1 and 2, a lead screw 5, which is rotatably supported on left and right side plates 3 and 4 that constitute a part of the main body of the printing device, passes through the carriage 2 to which the printing head 1 is attached. By rotationally driving this lead screw with a pulse motor 6, the carriage 2 is moved to the recording paper 7 through a protrusion (not shown) that engages with a groove of the lead screw.
The carriage 2 is moved in the width direction of the printer to print on the recording paper by the printing head 1.The carriage 2 has its back surface abutted against a guide portion 8 of the main body of the printer, and slides only in the lateral direction.

Below the lead screw 5, a feed roller shaft 9 whose both ends are rotatably supported by the side plates 3 and 4 is arranged in parallel, and paper feed rollers 10 are fixed to both sides of the feed roller shaft. ing. A cylindrical member 11 is rotatably mounted between the pair of paper feed rollers 10, and one end surface of this cylindrical member has teeth in which a one-way clutch 12 of a ratchet structure is formed. It is engaged with the roller 10, and the other end surface is pressed by a spring 13 installed between it and the paper feed roller. Further, a protruding cam 14 formed in a spiral shape with a predetermined lead angle is provided on the outside of the cylindrical member 11, and this cam engages with a groove 15 formed in the carriage 2. . With this structure, when the carriage 2 moves in the normal printing direction (from right to left in FIG.
1 rotates, but the rotating direction of the cylindrical member 11 at this time is the direction in which the one-way clutch 12 slips and does not transmit rotational force, so the paper feed rollers 10, 10 do not rotate during printing. . On the other hand, during a carriage turn when the carriage 2 moves from left to right in FIG. The paper feed roller shaft 9 and the left paper feed roller 10, which are integral with this, rotate by a predetermined angle (for example, 75 degrees) to feed the recording paper 7 (usually one line of paper feed).

A platen 16 is disposed at a position facing the print head 1 while sandwiching the recording paper 7, and a pinch roller 17 is disposed at a position facing the feed roller 10.

The platen 16 is attached to a platen holder 19 that is pivotably supported around a platen holder shaft 18, and the pinch roller 17 is
It is rotatably mounted on the same platen holder shaft 18. Incidentally, the platen holder shaft 18 is inserted into a long guide hole, which will be described later, formed in the left and right side plates 3 and 4, and the pinch roller 17
can be moved between a position where it is pressed against the feed roller 17 and an open position where it is separated from the feed roller.

A pressure spring 20 is installed between the back surface of the platen holder 19 and the main body of the printer, and the spring force presses the platen 16 against the print head 1 via the recording paper 7, and at the same time A pinch roller 17 is pressed against the feed roller 10 via the recording paper 7.

In addition, in FIG. 2, the recording paper 7 is placed on a roll sheet 2.
This shows the case of unwinding and supplying from 1, but
It can also be supplied as cut sheets.

However, in the conventional printing device of this type, the platen holder 19 is supported by a separate metal platen holder shaft 18, as shown in FIG. 17 was also rotatably fitted to this metal platen holder shaft 18. After this metal platen holder shaft is inserted through the left and right side plates 3 and 4, it is assembled by fitting a retaining ring 22 such as an E-ring into an annular groove formed at both ends.

However, in the conventional platen holder support structure as shown in FIG. Since it has to be mounted, there is a problem that the number of parts is large, the number of processing steps is also large, and the manufacturing cost is high.

(Objective) The object of the present invention is to provide a non-impact type printing device having a platen holder support structure that eliminates the drawbacks of the conventional platen holder support structure, has a small number of parts, and can significantly reduce manufacturing costs. The goal is to provide the following.

A feature of the present invention is that the above object is achieved by integrally molding the platen holder and the platen holder shaft.

(Description of Embodiments) FIGS. 4 to 8 illustrate embodiments of the present invention, and the present invention will be specifically described below with reference to these drawings. It should be noted that the parts of the non-impact type printing device according to the present invention other than those shown in the drawings have substantially the same structure as the parts described in FIGS. 1 and 2 above, and corresponding parts are designated by the same reference numerals. A detailed explanation thereof will be omitted.

In the embodiment described below, a platen holder shaft is inserted into the left and right guide slots formed in the printing device main body, and a pinch roller for paper feeding is rotatably attached to the platen holder shaft, and the platen holder is attached to the platen holder. A non-impact type printing device configured to be mounted so as to be swingable around a holder axis and to press a platen and a pinch roller against a print head and a paper feed roller by means of a spring, wherein the platen holder and the platen holder axis are integrally molded. However, the length of the guide slot on at least one side is increased to a range where the platen holder shaft can be assembled. Further, the spring for pressing the print head and paper feed roller described above also serves to prevent the platen holder from coming off.

In FIG. 4, the platen holder 19A to which the platen 16 is attached has a shape in which the corner portions of the lower ends on both sides are cut out, and platen holder shafts 18A, 18A protruding left and right are integrally molded in the cutout portions. There is. This platen holder 19A
The platen holder shaft 18A is integrally molded by injection molding of plastic such as ABS resin or die casting of metal such as zinc or aluminum. The platen holder (including the platen holder shaft 18A) 19A integrally molded in this way is attached to the left and right side plates (printing device main body) after the pinch rollers 17 are attached to the platen holder shaft 18A on both sides.
It is assembled by being inserted into the long guide holes (the long guide hole 23 in FIG. 5 and the long guide hole 24 in FIG. 6) formed in 3 and 4.

5 and 6 are diagrams illustrating the support structure of the side plates 3 and 4 on both sides of an embodiment of the non-impact type printing device according to the present invention, in which the platen holder 19
A has its shaft 18A inserted into the guide slot 2 of the left side plate 3.
3 and the right side plate 4, and are guided and supported through the guide slots 24. In the illustrated example, the guide hole 23 of the left side plate 3 is formed sufficiently long to the extent that the platen holder shaft 18A can be assembled to a side plate of a constant width. Guide slot 2
3 and 24 are formed with grooves for attaching pressure springs 20A (see FIG. 8) formed by pressure springs, that is, plate springs, which are installed between the platen holder 19A and the printer main body. . In addition, in FIGS. 5 and 6, the lead screw 5 and the feed roller shaft 9 are shown in FIGS. 1 and 2.
As in the case shown in the figure, it is rotatably supported.

When assembling the platen holder 19A shown in FIG. 4 to the printing device, as shown in FIG.
While attaching the platen 16, insert the pinch rollers 17, 17 into the pair of integrally molded left and right platen holder shafts 18A, 18A, respectively, and insert the one (right side) platen holder shaft 18A into the short (normal size) guide slot 24. , and insert the other platen holder shaft 18A from the rear end of the long guide hole 23 formed in the left side plate 3 in an oblique state as shown in the figure. In this way, platen holder 1
After inserting 9A into the long holes 23 and 24 on both the left and right sides,
As shown in FIG. 8, the pressure contact spring 20A is advanced to a position facing the printing head 1 engaged with the guide portion 8 of the printing device main body, and is then made of a plate spring formed in an arcuate shape as shown in FIG. The elastic force is used to engage the grooves formed in the left and right side plates 3 and 4 (see FIGS. 5 and 6). This prevents the platen holder from coming off the elongated hole. In this way, the platen holder and the pinch roller can be assembled in a predetermined position (in a pressed state) by an extremely simple operation.

According to the embodiment described above with reference to FIGS. 4 to 8, the platen holder 19A and the platen holder shaft 18A are integrally molded from plastic or metal, which greatly reduces the number of parts and the number of machining steps. A significant reduction in manufacturing costs can be achieved. Furthermore, weight can be reduced by omitting the conventional metal platen holder shaft (platen holder shaft 18 in Figure 3), and furthermore, by reducing the number of parts, it can be easily assembled as shown in Figures 7 and 8. It is possible to assemble the assembly into the same position, and the number of assembly steps can also be reduced.

In the above embodiment, only one of the guide holes 23 and 24 formed in the left and right side plates 3 and 4 (the left long hole 23) was formed sufficiently long to the extent that it could be assembled. are both long holes 23, 2
4 can also be formed long.

(Effects) As is clear from the above explanation, according to the present invention, the structure of the platen holder and pinch roller mounting part can be simplified, and the number of parts and processing steps can be reduced, resulting in a significant cost reduction. An impact type printing device is obtained.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view illustrating the main structure of a non-impact type printing device suitable for applying the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG.
The figure is an elevation view illustrating a conventional support structure for a platen holder and a pinch roller in a non-impact printing device, and FIG. 4 is an elevation view illustrating a support structure for a platen holder and a pinch roller in a non-impact printing device according to the present invention. The plan view, FIGS. 5 and 6 are diagrams illustrating the support structure on both the left and right sides of the platen holder and the pinch roller in the non-impact type printing device according to the present invention, as seen from the line - and line - in FIG. 8. 7 is an explanatory plan view illustrating the assembly procedure of the platen holder and pinch roller in the non-impact type printing device according to the present invention, and FIG. 8 is a side view showing the platen holder and pinch roller in the non-impact type printing device according to the present invention. FIG. 3 is an explanatory plan view illustrating a state in which the rollers are assembled. 1... Print head, 2... Carriage, 3, 4
... Side plate (printing device main body), 5 ... Lead screw, 7 ... Recording paper, 8 ... Guide section, 10 ... Paper feed roller, 12 ... One-way clutch, 14 ...
Cam, 15... Groove, 16... Platen, 17...
Pinch roller, 18, 18A...Platen holder shaft, 19, 19A...Platen holder, 20, 2
0A...Spring for pressure welding, 23, 24...Elongated hole for guide.

Claims (1)

[Scope of Claims] 1. A non-impact type printing device for recording on recording paper, comprising: a head for recording on recording paper; side plates provided to face each other; and a recess provided in the side plates; a platen roller shaft having a platen holder for holding the platen and a pinch roller and supported between the side plates with both ends engaged in the recess; and a spring for pressing the platen toward the head. The platen holder and the platen holder shaft are configured integrally so that at least one of the recesses is connected to the platen so that both ends of the platen roller shaft can be engaged with the recess from between the both side plates. A non-impact printing device characterized in that the size of the roller shaft is larger than that of the roller shaft, and the spring is also used to prevent the platen holder shaft from coming off from the recess.