JPS62225379A - Paper-feeding mechanism for printer - Google Patents

Abstract

PURPOSE:To enable a sprocket paper to be fed at a constantly fixed feed pitch without loosening even where a paper feed pitch of a platen is varied more or less, by setting the feed pitch of the platen to be larger than the feed pitch of a tractor mechanism, and rotating the tractor mechanism in a direction opposite to the rotating direction of the platen. CONSTITUTION:A platen 1 is rotatably supported on a frame 6, and a platen gear 7 is fitted to a platen shaft 1a. When feeding a sprocket paper, a motor 11 is rotated clockwise, whereby the gear 7 is rotated clockwise to rotate a rotary shaft 2a of a tractor mechanism 2 counterclockwise. Since the feed pitch of the platen 1 is larger than that of the tractor mechanism 2, a paper wrapped around the platen 1 is fed by the platen 1 in excess of the amount by which it is fed by the mechanism 2. However, since the mechanism 2 has a paper-holding force greater than that of the platen 1, the feed pitch of the mechanism 2 is not disturbed, and the paper is set into a stretched state between the mechanism 2 and the platen 1, and beyond that point, the paper slips on the platen 1. Accordingly, the paper can be fed at an accurate pitch without loosening.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding mechanism for a printer that feeds sprocket paper by selectively positioning a tractor mechanism in a pulling position and a pushing position with respect to a platen.

[Conventional technology]

Conventionally, as shown in FIG. 3, this type of paper feeding mechanism is provided with a tractor mechanism 2 rotatably positioned relative to the platen 1 to selectively position it in a pulling position shown by a solid line and a pushing position shown by a chain line. In the pull position, the drive shaft 2a of the tractor mechanism 2 and the platen 1 are rotated clockwise, and in the push position, the drive shaft 2a of the tractor mechanism 2 is rotated counterclockwise and the platen 1 is rotated clockwise to rotate the sprocket paper. It is configured to perform paper feeding of 3. In the figure, reference numeral 4 is a paper press roller, and 5 is a pinch roller that comes into contact with the platen 1 when feeding paper other than the sprocket paper 3.

[Problem that the invention seeks to solve]

By the way, in such a paper feeding mechanism, the feeding pitch of the tractor mechanism is generally accurate, and the force of feeding the sprocket paper is strong. On the other hand, the feeding pitch of the platen varies more than the feeding pitch of the tractor mechanism, and the force for feeding the paper is weaker. Therefore, for example, when feeding sprocket paper in a tension position, if the feed pitch of the platen is smaller than the feed pitch of the tractor mechanism, the tractor mechanism will slip the sprocket paper against the platen and feed the sprocket paper at an accurate feed pitch. However, if the platen feed pitch is larger than the tractor mechanism feed pitch, the sprocket paper will become slack before the tractor mechanism. On the other hand, when feeding sprocket paper at the push-in position, if the platen feed pitch is larger than the tractor mechanism feed pitch, the sprocket paper will not loosen, but if the platen feed pitch is smaller than the tractor mechanism feed pitch, the sprocket paper will loosen. It turns out.

In this way, variations in the feed pitch of the platen appear as opposite phenomena between the pulling position and the pushing position of the tractor mechanism, so conventionally, high processing accuracy was required for the platen.
The drawback was that it led to an increase in costs.

The present invention was developed in view of the above circumstances, and its purpose is to always feed paper at a constant feeding pitch without loosening the sprocket paper even if there are slight variations in the paper feeding pitch of the platen. The purpose of the present invention is to provide a paper feeding mechanism for a printer that can be used.

[Means for solving problems]

In order to achieve the above object, the present invention is characterized in that the feed pitch of the platen is set larger than the feed pitch of the tractor mechanism, and the tractor mechanism is rotated in the opposite direction to the rotation direction of the platen. .

[For production]

According to the above configuration, when feeding the sprocket paper at the push-in position, the sprocket paper is fed by the platen more than the tractor mechanism, but since the tractor mechanism has a stronger holding force for the sprocket paper, the sprocket paper is fed by the tractor mechanism. and the platen. In addition, when feeding sprocket paper in the tension position, the platen rotates in the direction that returns the sprocket paper against the feeding direction of the tractor mechanism, but since the tractor mechanism has a stronger feeding force for the sprocket paper, the sprocket paper is and the tractor mechanism.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention, in which FIG.
This shows the state of the paper feed mechanism when pushed in by
FIG. 2 similarly shows the state of the paper feeding mechanism when the sprocket paper is pulled against the platen 1 by the tractor mechanism 2.

In addition, the same parts in the figure as in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted.

In FIGS. 1 and 2, the platen 1 is rotatably held by a frame 6, and the platen shaft 1 of the platen 1 is
A platen gear 7 is attached to a. This platen gear 7 meshes with a motor gear 10 fixed to a motor 11 via gears 8 and 9, so that the rotational force of the motor 11 is transmitted. Further, the tractor mechanism 2 is rotatably held by the frame 6 via a guide shaft 12, and a drive shaft 2a of the tractor mechanism 2 has a tractor gear 13.
is equipped. This tractor gear 13 meshes with the platen gear 7 via an idler gear 14, 15 when the tractor mechanism 2 is in the pushed-in position shown in FIG.
When the tractor mechanism 2 is in the tensioned position shown in FIG. 2, it meshes with the platen gear 7 via idler gears 16, 17. Note that the feeding pitch of the platen 1 is larger than the feeding pitch of the tractor mechanism 2.

In the above configuration, when feeding the sprocket paper at the push-in position, the motor 11 is rotated clockwise.

When motor 11 rotates clockwise, gear 8.9 rotates counterclockwise, causing platen gear 7 and platen 1 to rotate clockwise.

When the platen gear 7 rotates clockwise, rotational force is transmitted to the tractor gear 13 via the idler gear 14.15, causing the rotation shaft 2a of the tractor mechanism 2 to rotate counterclockwise. At this time, since the feed pitch of platen 1 is larger than the feed pitch of tractor mechanism 2, the sprocket paper wrapped around the outer periphery of platen 1 is fed more by platen 1 than by tractor mechanism 2, but tractor mechanism 2 is faster than tractor mechanism 2. Since the holding force of the sprocket paper is strong, the feeding pitch of the tractor mechanism 2 is not disturbed, and the sprocket paper remains stretched between the tractor mechanism 2 and the platen 1. Further, since the sprocket paper will slide on the platen 1, the sprocket paper will not loosen and will be fed at an accurate feeding pitch.

On the other hand, when feeding the sprocket paper in the tension position, the motor 11 is rotated counterclockwise.

When the motor 11 rotates counterclockwise, the gear 8°9 rotates clockwise, causing the platen gear 7 and the platen 1 to rotate counterclockwise. When the platen gear 7 rotates counterclockwise, rotational force is transmitted to the tractor gear 13 via the idler gears 16 and 17, causing the rotating shaft 2a of the tractor mechanism 2 to rotate clockwise. At this time, the platen 1 rotates in the direction (counterclockwise) that returns the sprocket paper against the feeding direction of the tractor mechanism 2, but since the tractor mechanism 2 has a stronger paper feeding force, the sprocket paper is moved between the platen 1 and the tractor. It is in a tensioned state with the mechanism 2. Further, since the sprocket paper will slide on the platen 1, the sprocket paper will not loosen and will be fed at an accurate feeding pitch.

In this embodiment, the feed pitch of the platen 1 is set larger than the feed pitch of the tractor mechanism 2, and the tractor mechanism 2 is rotated in the opposite direction to the rotation direction of the platen 1, so that the slack of the sprocket paper can be prevented. Even if there is some variation in the paper feeding pitch of the platen, the sprocket paper can always be fed at a constant feeding pitch.

〔Effect of the invention〕

As explained above, according to the present invention, the feeding pitch of the platen is set larger than the feeding pitch of the tractor mechanism, and the tractor mechanism is rotated in the opposite direction to the rotating direction of the platen. Even if there is some variation, the sprocket paper will not loosen,
It is possible to provide a paper feeding mechanism for a printer that can always feed paper at a constant feeding pitch.

[Brief explanation of drawings]

1 and 2 show one embodiment of the present invention, FIG. 1 is an explanatory diagram showing the state of the paper feeding mechanism when the sprocket paper is pushed into the platen by the tractor mechanism, and FIG. On the other hand, FIG. 3 is an explanatory diagram showing the state of the paper feeding mechanism when the sprocket paper is pulled by the tractor mechanism, and FIG. 3 is a configuration diagram of the conventional paper feeding mechanism. DESCRIPTION OF SYMBOLS 1... Platen, 2... Tractor mechanism, 7... Platen gear, 10... Motor, 13... Tractor gear, 14-17... Idler gear. Applicant's agent Patent attorney Takehiko Suzue U Figure 1

Claims (1)

[Claims] In a paper feeding mechanism of a printer that feeds sprocket paper by selectively positioning a tractor mechanism in a pulling position and a pushing position with respect to a platen, the feeding pitch of the platen is set to be larger than the feeding pitch of the tractor mechanism; A paper feed mechanism for a printer, characterized in that a tractor mechanism is configured to rotate in a direction opposite to the rotation direction of a platen.