JPH0592631A - Printer paper feed roller - Google Patents

Abstract

PURPOSE:To enable paper to be cirtainly discharged by preventing precision in printing from decreasing by feeding caper smoothly by a method wherein a collar part of which a diameter is larger than a roller body is provided to one end part of the roller body, and a peripheral surface of the collar part is made to be a highly frictional engaging surface. CONSTITUTION:A collar part of which a diameter is larger than a roller body 11 is provided integrally to one end part of the roller body 11, and a peripheral surface 14 of the collar part 13 is made to be a highly frictional engaging surface which is small in a difference between projection and depression Even though a tip of paper P which is sent to a caper feed roller 10 after passing through a printing part, hits against each projection formed to the peripheral surface 14 of the collar part 13, since the projection 15 is low in height and cylindrical, it is likely not to be caught and paper feed is not intercepted thereby. Then, the paper can be smoothly fed and precision in printing can be prevented from decreasing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed roller for a printer.

[0002]

2. Description of the Related Art FIG. 5 and FIG. 6 show a schematic configuration of a conventional printer.

In these drawings, reference numeral 1 denotes a printing section, which is composed of, for example, a print head 2 and a platen 3.
A pair of feed rollers 4 for feeding the paper and a pinch roller 5 are provided upstream of the printing unit 1 in the paper transport direction so as to be rotatable in the arrow direction. A paper feed roller 6 that cooperates with a pinch roller 9 to feed and discharge the paper is provided downstream of the printing unit 1 in the paper transport direction so as to be rotatable in the arrow direction via a shaft 6a.

As shown in FIG. 5, one end of the roller body of the paper feed roller 6 is provided with a gear-shaped convex portion 7 for instantaneously urging the paper P in the paper ejection direction during paper ejection. .. This convex portion 7 is formed with a diameter larger than that of the roller body that contacts the pinch roller 5 of the paper feed roller 6, and the convex portion 7 has a plurality of teeth 8 of a predetermined height (for example, 1 to 1.5 mm). They are provided at predetermined pitch intervals.

However, the paper P fed to the right in FIG. 6 by the cooperation of the feed roller 4 and the pinch roller 5 is inserted between the paper feed roller 6 and the pinch roller 9, and the rollers 4, 5, 5 are inserted. After being fed by a predetermined distance by 6 and 9, the paper feed roller 6 and the pinch roller 9 cooperate to eject the paper in a predetermined direction. At the time of this discharge, the sheet P is instantaneously biased in the discharge direction by the convex portion 7. As a result, the paper P
The trailing end of the sheet is surely removed from between the paper feed roller 6 and the pinch roller 9 and is smoothly discharged.

[0006]

In the printer described above, the leading edge of the paper P fed by the feed roller 4 and the pinch roller 5 hits the teeth 8 of the convex portion 7 of the paper feed roller 6 and conveys the paper. May be disturbed. When such a situation occurs, a printing accuracy defect occurs such that the paper feeding accuracy is lowered and the printing line pitch interval is narrowed, or in an extreme case, overlapping printing is performed.

Incidentally, as shown in FIG. 7, there is one in which a disc-shaped member made of urethane foam is attached to one end of the paper feed roller 6 by using a double-sided tape or the like to form a convex portion 7 '. It is not practical because it has a problem that the part 7 ′ is naturally hydrolyzed and eventually collapses into pieces and is destroyed, and there is a problem that it takes a lot of time to attach it.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a paper feed roller for a printer, which is capable of smoothly feeding the paper to prevent a decrease in printing accuracy and to reliably eject the paper.

[0009]

SUMMARY OF THE INVENTION The present invention is a paper feed roller for a printer having a roller body that is rotatably disposed downstream of a printing unit in the paper feed direction and cooperates with a pinch roller to feed and discharge the paper. In at least one end of the roller body, a flange having a diameter larger than that of the roller body is provided, and a peripheral surface of the flange is a high friction engagement surface having a small difference in unevenness.

[0010]

According to the present invention, the leading edge of the paper, which has passed through the printing portion and is fed to the paper feed roller, is the peripheral surface (high friction engagement surface) of the collar portion.
Even when hitting, the difference in unevenness of the peripheral surface (high friction engagement surface) is small, so that it does not get caught and does not interfere with the sheet feeding. This makes it possible to smoothly feed the paper and prevent the printing accuracy from deteriorating.

Further, when the paper is discharged, the peripheral surface (high friction engagement surface) of the collar portion instantaneously urges the paper in the discharge direction.
The trailing edge of the paper does not remain between the paper feed roller and the pinch roller, and the paper is reliably discharged.

Therefore, it is possible to smoothly feed the paper, prevent the printing accuracy from deteriorating, and reliably eject the paper.

[0013]

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

Paper feed roller 1 of the printer according to this embodiment
As shown in FIGS. 1 to 4, 0 is rotatably arranged downstream of the printing unit 1 (print head 2, platen 3) in the paper transport direction and cooperates with the pinch roller 9 to feed and discharge the paper. It is configured.

The same components as those shown in FIGS. 5 and 6 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

Here, the paper feed roller 10 has a roller body 11 which is brought into pressure contact with the pinch roller 9. The roller body 11 is rotatably provided via a shaft 12. As shown in FIG. 1, a flange 13 having a larger diameter than the roller body 11 is integrally provided at one end of the roller body 11. The peripheral surface 14 of the flange portion 13 is a high friction engagement surface with a small difference in unevenness.

In this embodiment, the peripheral surface 14 of the collar portion 13 is
A large number of low-conical projections 15 are provided on the to form a high friction engagement surface. In addition, the collar portion 13 is configured to have elasticity so as to more surely apply a momentary force to the sheet when the sheet is discharged. In this embodiment, FIG.
The roller body 11 corresponding to the collar portion 13 is indicated by diagonal lines in FIG.
The structure is configured to increase elasticity by stealing a portion of meat and forming the hollow portion 19.

Next, the operation will be described.

Even if the front end of the paper P sent to the paper feed roller 10 after passing through the printing unit 1 hits each projection 15 formed on the peripheral surface 14 of the flange 13, the projection 15 is short and conical. Since it has a shape, it does not get caught and does not interfere with paper feeding. This makes it possible to smoothly feed the paper and prevent the printing accuracy from deteriorating.

When the paper is discharged, the projections 15 of the collar 13 momentarily urge the paper P in the discharging direction, so that the rear end of the paper P is located between the paper feed roller 10 and the pinch roller 9. The paper P is not discharged and the paper P is surely ejected.

According to this embodiment, however, a flange portion 13 having a diameter larger than that of the roller body 11 is provided at one end of the roller body 11, and the peripheral surface 14 of the flange portion 13 has a short conical shape. Since the high friction engagement surface is formed by the large number of projections 15, the leading edge of the sheet is prevented from being caught and the sheet is smoothly fed. As a result, it is possible to prevent a decrease in printing accuracy and to reliably discharge the paper.

Further, the roller body 11 corresponding to the collar portion 13
Since the structure is designed to steal the portion and increase elasticity, the paper can be more reliably carried out.

Further, since the collar portion 13 is formed integrally with the roller body 11, the structural strength can be increased and the cost can be reduced.

Furthermore, since a large number of short cone-shaped projections 15 are provided on the peripheral surface 14 of the flange portion 13 to form a high friction engagement surface, even if the leading edge of the paper strikes the projections 15, it is easy to come off and is much more difficult. The paper can be fed with high accuracy.

In the above embodiment, a large number of protrusions 15 are provided on the peripheral surface 14 of the flange 13 to form a high friction engagement surface. However, if the friction coefficient of the peripheral surface 14 can be increased, It may be formed in any way. For example, the peripheral surface 14 of the flange 13 may be knurled to form a high friction engagement surface.

Alternatively, the collar portion 13 may be formed separately from the roller body 11 and mounted on the roller body 11.

Further, the collar portion 1 is provided on both ends of the roller body 11.
3,3 may be provided.

[0028]

According to the present invention, a flange portion having a diameter larger than that of the roller body is provided at one end portion of the roller body, and the peripheral surface of the flange portion serves as a high friction engagement surface. Is prevented and the paper is fed smoothly. This allows
The printing accuracy is prevented from being degraded. Further, it is possible to reliably discharge the paper.

[Brief description of drawings]

FIG. 1 is a diagram showing a positional relationship between a paper feed roller body and a pinch roller according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a printer to which an embodiment is applied.

FIG. 3 is a perspective view showing a roller body integrally formed with a collar portion according to an embodiment.

FIG. 4 is a diagram for explaining a roller main body near a collar portion.

FIG. 5 is a diagram showing a schematic configuration of a conventional paper feed roller.

FIG. 6 is a diagram showing a schematic configuration of a printer to which a conventional paper feed roller is applied.

FIG. 7 is a diagram showing a paper feed roller to which a convex portion made of urethane foam is attached.

[Explanation of symbols]

 1 Printing Section 10 Paper Feed Roller 11 Roller Main Body 13 Collar 14 Circumferential Surface

Claims (1)

[Claims] 1. A paper feed roller of a printer having a roller main body which is rotatably disposed downstream of a printing unit in the paper transport direction and cooperates with a pinch roller to feed and discharge the paper, at least one end of the roller main body. A paper feed roller for a printer, characterized in that a flange portion having a diameter larger than that of the roller body is provided in the portion, and the peripheral surface of the flange portion is a high friction engagement surface with a small difference in unevenness.