JPS6236264A - Paper sheet feeding mechanism for printer - Google Patents

Abstract

PURPOSE:To permit the feed of the continuous paper in the range from thin paper to thick paper by forming the step difference in the circumferential direction and at a part in the axial direction on the cuter periphery of a bail roller and intermittently releasing the excessive fed portion of a platen roll which is accumulated when the thin continuous paper is fed. CONSTITUTION:At least one stop difference 5a, 5a' larger than the thickness of thin paper is installed in the circumferential direction and a part in the axial direction of a bail roller 5, 5'. Then, though a thick paper sheet A2 is strongly pressed by the circumference of the bail roller 5, 5', in case of a thin paper sheet A1, slip is generated at the step difference part 5a, 5a' at least one time during revolution. The generation of excessive tension force is suppressed by releasing the accumulated excessively fed portion. Therefore, the feeding of continuous sheet of paper in a wide range from thin paper to thick paper is permitted by varying the position of the bail roller 5, 5'. Further, operation is facilitated, and the paper feeding faculty is not deteriorated with the simple constitution.

Description

[Detailed Description of the Invention] [Summary] A paper feeding mechanism of a printer in which a step is provided on a part of the outer periphery of the bail roller to intermittently release overfeed of the platen roll that accumulates during continuous paper feeding of thin paper. With this configuration, it is possible to feed a wide range of continuous paper ranging from thin paper to thick paper.

[Industrial application field]

The present invention relates to a paper feeding mechanism for feeding continuous paper in a printer, and more particularly, to a paper feeding mechanism that allows feeding of a wide range of paper ranging from thin paper to thick paper.

Paper feeding mechanisms for printers include a single sheet feeding mechanism that uses only rotation of a platen roll, and a continuous paper feeding mechanism that uses rotation of a platen roll and a tractor.

[Conventional technology]

Therefore, in the conventional continuous paper feeding mechanism, as shown in FIG. When engaged, paper A is fed into the platen roll 1 side. At the same time, the platen roll l rotates and is configured to send out the paper A by the action of the bail roller 5 which presses the paper A thereon.

The bail roller 5 is made of plastic or a cylinder wrapped with rubber and has the same diameter, and has a predetermined coefficient of friction.
It is movable relative to the shaft 6 according to the width of the paper A, and a constant pressing force is always applied by a spring force or the like. The amount of feed by the platen roll 1 and bail roller 5 is set to A+α with respect to the feed fiA of the tractor 3, so that the paper A does not sag at the print head 2 portion. Therefore, there is slippage between the platen roll 1 and the pail opening 5 by an amount of overfeed α.

[Problem that the invention seeks to solve]

By the way, in the conventional structure described above, since the friction coefficient and pressing force of the bail roller 5 are constant, it cannot be applied to changes in the thickness of the paper A.

That is, if the pressing force of the bail roller 5 is weak in the case of cardboard,
The fold of paper A protrudes as shown by the dashed line in the figure, resulting in printing defects and inability to feed. Furthermore, in the case of thin paper, the frictional force of the bail roller 5 increases and the amount of slip becomes extremely small, resulting in problems such as overfeeding accumulates and the printing position shifts and the feed holes are torn.

The present invention was created in view of these points, and an object of the present invention is to provide a paper feeding mechanism for a printer that can satisfactorily feed continuous sheets of different thicknesses using simple means.

[Means for solving problems]

In order to achieve the above object, the present invention, as shown in FIG. Step 5a, 5a/
Provide at least one.

In the case of thin paper AI, it is pressed only at the steps 5a and 5a' of the bail roller 5.5', and in the case of thick paper A2, it is pressed at the part off the step 5as5a' of the bail roller 5.5'. has been done.

[Effect]

Based on the above configuration, thick paper A2 is always pressed strongly by the circumference of bail roller 5.5', but thin paper A2 is always pressed strongly by the circumference of bail roller 5.5'.
, if the bail roller 5.5' slips at least once at the steps 5a and 5aI in one rotation,
The accumulated overfeed is released and no extra tension is generated. Thus, in the present invention, the bail roller 5.5
By changing the position of ', it is possible to smoothly feed a wide range of continuous sheets ranging from thin paper to thick paper.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1(a), reference numeral 6 denotes a shaft, and 5.5' denotes a bail roller movably attached to the shaft 6. It is a part of the outer periphery of this bail roller 5.5' in the circumferential direction, and one end There are steps 5a, 5 in the axial direction from
a' are provided in the same manner. Step 5 a % 5 a'
The depth is slightly larger than the thickness of thin paper (paper of 50 g/d or less).

In the case of thin paper A, as shown by the solid lines in (b) and (C), two bail rollers 5.5' are arranged on both sides of the paper with the steps 5a and 5a I inside, and the steps 5a
, 5 a Press so that only the part I covers the paper A1. On the other hand, in the case of thick paper A2, the operator moves the bail roller 5.5' inward as shown by the dashed line in FIG. Then, set the pressing force to a strong level suitable for cardboard.

The operation of the paper feeding mechanism configured in this way will be explained.

First, in the case of thin paper A+, the steps 5as5a' of the bail roller 5.5' are applied to both sides of the paper AI and pressed against it, so that the bail roller 5.5' also rotates when the platen roll 1 rotates to feed the paper. At this time, the steps 5a and 5a' come to the paper A once in one rotation and do not substantially press the paper A. Therefore, the overfeed accumulated on the sheet A1 in the slip state is released, and the sheet AI is thus smoothly sent out by the bail roller 5.5' while reducing the excess tension.

For thick paper A2, use bail roller 5.5' for paper A2.
By applying the circumference of , this is done regardless of the existence of the steps 5a and 5a'. Then, due to the strong pressing force of the bail roller 5.5', the paper A.

The paper is fed without any creases popping out.

Incidentally, although the case where there is one step 5as5a' has been described,
A plurality of bail rollers may be provided on the circumference of the bail roller 5.5'.

Also, by changing the number of bail rollers 5.5' in the axial direction, 2
It is also possible to provide more than one stage, and by doing so, it is possible to respond more precisely to changes in paper thickness.

On the other hand, in the case of sheets such as copy sheets in which a plurality of sheets are stacked one on top of the other, if the pressing force of the bail roller is strong, the rotational load may cause interlayer misalignment.

Therefore, in this case, as shown in FIG. 2, a bearing 7 is assembled between the shaft 6 inside the bail roller 5, the removal is prevented by a stopper member 8, and the C-ring 9 is used for positioning. Configure.

As a result, even if the pressing force of the bail roller 5 is strong, the rotational load is reduced by the bearing 7, making it possible to prevent interlayer displacement of the copy paper.

〔Effect of the invention〕

As described above, according to the present invention, a wide range of continuous paper ranging from thin paper to thick paper can be fed satisfactorily.

The operation is easy because the operator only needs to change the position of the bail roller according to the paper thickness, and it is also possible to perform the operation during printing.

Since this method uses the step of the bail roller to relieve overfeeding in the case of thin paper, the structure is simple and there is no risk of impairing the paper feeding function.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view showing the main parts of an embodiment of the paper feeding mechanism of the present invention, FIG. 1(b) is a plan view of the same main parts, FIG. 1(c) is a side view, and FIG. A sectional view showing the embodiment, and FIG. 3 is a side view of the conventional example. In FIG. 1, 5.5' is a bail roller, and 5a, 5aL are steps.

Claims (1)

[Claims] Paper transport (3) that feeds paper to the platen roll (1)
In a paper feeding mechanism equipped with bail rollers (5) and (5') that press the printed paper against the platen roll (1), there is a step (5a) on a part of the outer periphery of the bail rollers (5) and (5'). , (5a') are provided, and the step (5a) of the bail rollers (5), (5') is provided depending on the paper thickness.
), (5a'), or a portion outside of these, is pressed against the paper to feed the paper.