JPH02136262A - Paper feed mechanism of printer - Google Patents

Abstract

PURPOSE:To always feed paper stably by providing a roller for pressing the paper to the outer peripheral surface of a sprocket or that of a tractor unit to the paper contact part of the sprocket or the tractor unit. CONSTITUTION:A roller 6 energizing paper 5 in a pressing direction is provided to the paper contact part of a sprocket 3 or a tractor unit 4 and the pressing force thereof is set so as to form F1 < N + F2 when the drive load of the roller 6 is set to N, the feed force of the paper 5 due to the friction of the sprocket 3 or the tractor unit 4 is set to F2 and the feed force of the platen 1 and a bail roller 2 is set F1. As a result, the paper 5 is oversupplied as compared with the feed quantity of the sprocket 3 or the tractor unit 4 by the feed force F1 so as not to be slackened between the platen 1 and the sprocket 3 or the tractor unit 4 but slip force is generated between the platen 1 and the paper 5 and the paper 5 can be oversupplied without damaging the feed holes of the paper 5.

Description

[Detailed Description of the Invention] [Summary] Regarding the paper feeding mechanism of a printer device, the purpose is to always enable stable paper feeding regardless of the state of the platen. and a sprocket or a tractor unit that feeds paper to a platen, and in a paper feed mechanism of a printer device that conveys continuous form paper, the paper is placed on the paper contact portion of the sprocket or tractor unit, and the paper is placed on the outer periphery of the sprocket or tractor unit. It is configured to include a roller that presses against the surface.

[Industrial application field]

The present invention relates to a paper feeding mechanism of a printer device.

Currently, there are a large number of types of paper used in printers, which differ in properties such as the slipperiness of the surface, rigidity, and the way in which the multi-bryer is fastened. Particularly in foreign countries, there are large differences in their properties compared to Japan, and various types of paper are used in printers. For this reason, depending on the paper, it may not be possible to feed it sufficiently, or it may be fed too much and become loose (
Paper is damaged by the sprocket), resulting in a paper jam. Further, the amount of interlayer deviation may become too large, and jams may occur due to this.

For this reason, stable paper feeding is required regardless of the properties of the paper.

[Conventional technology]

As shown in FIG. 8(a) or (b), a conventional printer device includes a platen 1, a bail roller 2 that contacts the platen 1, and a sprocket 3 or a tractor unit 4. Continuous form sheets 5 are sent out in the direction of arrow P by bin feed by the platen 1 and friction feed by the platen 1 and bail roller 2.

[Problem to be solved by the invention]

In the conventional paper feeding mechanism described above, the balance between the paper feeding amount by friction feed and the paper feeding amount by bin feeding has been a problem. In particular, in the case of friction feed, the following problem arises because the paper 5 is fed by the frictional force between the paper 5 and the platen 1 that is generated by the force of the bail roller 2 pressing toward the platen 1.

It is difficult to make the amount of paper fed by friction feed exactly equal to the amount of paper fed by bin feed due to the machining accuracy of various parts and changes over time. It is slightly larger than the feed amount. Therefore, the paper does not sag in the printing section, and printing quality can be ensured. However, for this to work without problems, the frictional force between the platen 1 and the paper 5 must be smaller than the paper holding force of the sprocket 3 or the tractor unit 4.

However, since the paper holding force of the sprocket 3 or the tractor unit 4 largely depends on the strength of the paper itself, the frictional force between the platen 1 and the paper 5 cannot be made very large. However, if the frictional force between the platen 1 and the paper 5 is too small, slack will occur between the platen 1 and the sprocket 3 or the tractor unit 4, causing a paper jam. For this purpose, an appropriate friction force is required, but the friction coefficient of the paper 5 used ranges from large to small, and the friction coefficient of the platen 1 also varies and changes over time, so it cannot be stabilized. There is a problem in that the range of paper that can be sent is limited.

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide a paper feeding mechanism that can stably feed a wide range of paper.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 1 is a platen, 2 is a bail roller, 3 is a sprocket, and 4 is a tractor unit, and these structures are the same as the conventional example explained in FIG. 4 is provided with a roller 6 which is biased in the direction of pressing the paper 5.

Note that the pressing force of the roller 6 is the driving load of the roller 6, which is N=
Let αP (α: constant) be the paper feeding force due to friction of the sprocket 3 or tractor unit 4 as F2−(μ
P) and the feed force at platen 1 and bail roller 2 is F, then the paper 5 is moved between platen 1 and platen 1 by the feed force F1 of platen 1 and bail roller 2 so that F,<N+F2. In order to prevent slack between the sprockets 3 or the tractor unit 4, the feed is over-feeded compared to the feed amount of the sprockets 3 or the tractor unit 4.

Conventionally, if this F (feeding force at the platen 1 and bail roller 2) is too large, the feeding hole for the paper 5 in the sprocket 3 or the tractor unit 4 is damaged, resulting in a paper jam. According to the present invention, the paper 5 is held by the sprocket 3 or the tractor unit 4 with a force of N+F2, and since there is a relationship of F+<N+F2, a sliding force is generated between the platen 1 and the paper 5, and the feed hole of the paper 5 is Overfeeding is possible without damage.

[Embodiment] FIG. 2 is a diagram showing an embodiment of the present invention, in which (a) is a top view, (b) is a front view, and (C) is a side view.

In the figure, 10 is a sprocket, 11 is a square shaft that drives the sprocket, 12 is a housing, 13 is a paper holder, and 14 is a roller, which is the main point of the present invention. This roller 14 is divided into two parts so as to avoid the bin 10a of the sprocket 10, as shown in FIG.
As shown in the figure, the shaft 15 is located approximately in the center of the paper holder 13.
As shown in FIG. 2, by pulling the paper holder 13 assembled into the housing 12 downward by a spring 16, the roller 14 is pushed and attached to the outer periphery of the sprocket 10. ing. Note that instead of the roller 14, a belt 17 may be used as shown in FIG.

Note that when the pressing force of the roller 4 or the belt 17 on the sprocket 10 is large, the roller 4
Or belt roller 8 and sprocket 10 with gear 19
．． 20 is provided so that the roller 4 or belt 17 is gear driven rather than friction driven.

The spring 16 is also stronger than the conventional one so that P > (where P is the pressing force of the low α 10μ, F is the feed force between the platen and bail roller, and μ is the coefficient of friction between the roller or belt and the paper). do.

Furthermore, although the sprocket 10 is conventionally made of resin and has a small friction coefficient on the paper contact surface, as shown in FIG. 6, a rubber layer 21 is provided on the surface (shaded area) to increase the friction coefficient.

In this embodiment configured in this way, as shown in FIG. 10
Since the sprocket 10 is pressed by 19, the frictional force between the sprocket 10 and the paper increases, which can overcome the tensile force exerted by the platen and the bail roller, allowing stable paper feeding. At this time, if the rotational resistance of the roller 14 or the belt roller 18 is large, when multivert paper is used, it may cause misalignment between the paper on the roller or belt side and the paper on the sprocket side. The smaller the better.

〔Effect of the invention〕

As described above, according to the present invention, paper holes are not damaged due to excessive feeding force of paper having low strength, and paper jam does not occur. This also makes it possible to increase the feed force of the platen and bail roller to sufficiently feed thick, rigid paper that requires a large feed force to overfeed, allowing stable paper feed for various types of paper. becomes possible. Furthermore, when multivert paper is used, the present invention, in which the paper is tightly sandwiched between a sprocket or a tractor unit and rollers, has the effect of preventing interlayer displacement.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram illustrating the principle of the present invention, Fig. 2 is a diagram showing an embodiment of the present invention, Fig. 3 is a diagram showing a roller of an embodiment of the present invention, and Fig. 4 is a diagram showing a roller of an embodiment of the present invention. Figures showing other embodiments of the present invention, Figure 5 is a diagram showing a roller driving means of an embodiment of the present invention, Figure 6 is a diagram showing a sprocket of an embodiment of the present invention, Figure 7 is a diagram showing a sprocket of an embodiment of the present invention. FIG. 8, which is a diagram showing the usage state of the embodiment, is a diagram showing a paper feeding mechanism of a conventional printer device. In the figure, 1 is a platen, 2 is a bail roller, 3 is a sprocket, 4 is a tractor unit, 5 is paper, and 6 is a roller.

Claims (1)

[Claims] 1. A platen (1), and a paper (5) on the platen (1).
It is equipped with a bail roller (2) that presses the paper (5) and a sprocket (3) or a tractor unit (4) that feeds the paper (5) to the platen (1).
5) In the paper feeding mechanism of the printer device that conveys the sprocket (3) or tractor unit (4)
A paper feeding mechanism for a printer device, characterized in that a roller (6) for pressing the paper (5) against a sprocket or an outer circumferential surface of a tractor unit is provided in a paper contacting portion of the printer.