JPH04238070A - Paper feeder - Google Patents

Abstract

PURPOSE:To solve a problem of jamming by smoothing insertion of paper by a method wherein a paper pressing means which presses or releases a paper feed roller is provided thereon and besides, a paper-pressing rotation-transmitting means which transmits rotary force to the paper pressing means in releasing is provided. CONSTITUTION:Recording paper 2 fed by a paper feed means 13 hits against a paper pressing means 7 with a paper feeder under a released state. Since paper-pressing rotation-transmitting means 14 consisting of an elastic material are installed on both ends of a paper feed roller 6 and comes in weak pressure contact with a cylinder 7c of the paper pressing means 7, the cylinder 7c and a rubber 7d are rotated in the directions indicated by the arrows by rotation of the paper feed roller 6 to carry a tip of recording paper 2 upward. After carrying a specific length of paper, an eccentric shaft 7a of the paper pressing means 7 is rotated by 180 deg., and the rubber 7d comes in pressure contact with the paper feed roller 6. The transmitting means 14 comes in pressure contact with the cylinder 7c to be in a deformed state. With respect to the paper delivery speed in release of paper feed, since the rotary speed of the rubber 7d is increased by the diameter ratio of each member, the recording paper 2 is inserted while its tip is being conducted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device for conveying recording paper in a printer or the like.

0002

2. Description of the Related Art In general, a conventional paper feeding device, as shown in FIG.
3. The paper pressing roller 23 is pivotally supported by a lever 24. One end 24a of the lever 24 is pivotally supported by the machine frame 26, and the other end 24b is pulled counterclockwise by a spring 25 provided between the lever 24 and the machine frame 26.

[0003] Reference numeral 27 is a cam pivotally supported on the machine frame. When the cam 27 is in the illustrated state, the counterclockwise rotation of the lever 24 is not restricted by the cam 27, and therefore the paper press roller 23 holds the recording paper 21 between it and the paper feed roller 22. to apply pressing force. When the cam 27 rotates 180 degrees from the illustrated state, the lever 24 is rotated clockwise by the action of the cam 27, and the pressure of the paper pressing roller 23 is released. In such a device, in order to feed paper appropriately, especially in a thermal transfer recording device with a large paper feeding load, for example, the pressing force of the paper pressing spring 25 may be increased, or the coefficient of friction between the paper feeding roller 22 and the recording paper 21 may be increased. This has been dealt with by increasing the angle at which the recording paper 21 wraps around the paper feed roller 22. Therefore, the recording paper 21
As shown in the figure, the conveyance route was curved.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, the curved conveyance path of the recording paper 21 causes the leading edge of the recording paper to hit, for example, the paper pressing roller 23 on the conveyance path, especially when the recording paper is inserted, resulting in jamming. The problem was that it caused problems such as

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding device that rotates a paper pressing means when inserting paper (when releasing paper), thereby facilitating paper insertion.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the paper feeding device of the present invention includes a paper feeding roller that rotates by receiving a driving force, and a paper pressing means that presses or releases the paper feeding roller. and paper presser rotation transmitting means for transmitting rotational force to the paper presser means when released. Here, it is preferable that the speed of the paper feeding section when the paper feeding roller and the paper pressing means are released is higher than that of the paper feeding roller. Further, the paper presser rotation transmission means is made of an elastic body, and can be constructed by being inserted into the paper feed roller.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view of a thermal transfer recording apparatus incorporating a paper feeding device of the present invention. In this thermal transfer recording device 1, a thermal head 4 presses against a platen 5 via an ink ribbon 3 on a recording paper 2, melts or sublimates ink on the ink ribbon 3 according to data, and transfers the ink onto the recording paper 2. let After the transfer, the recording paper 2 is transferred to the paper feed roller 6
The paper is held by the paper holding means 7, fed by a predetermined amount, and discharged. After the paper is discharged, the paper pressing means 7 is released from pressing against the paper pressing roller 6 by the rotation of the gear 9 driven by the motor 8, as will be described later.

In the thermal transfer recording apparatus 1, a thermal head 4 is pressed against a platen 5 with a high load by a spring 10 in order to achieve high printing quality. A platen pressure roller 11 contacts the platen 5 equipped with an elastic body such as rubber, which presses and releases the platen 5 against the thermal head 4 and prevents the platen 5 from being bent due to the pressure. Therefore, as the feeding load of the recording paper 2, the load due to the deformation of the elastic body of the platen 5, the load due to the deformation of the elastic body of the platen 5, the load caused by the thermal head 4 and the ink ribbon 3, etc.
Since friction between the platen 5 and the recording paper 2 causes loads, etc., a sufficient paper feeding force is required.

Therefore, in this embodiment, in order to increase the pressing force of the paper pressing means 7 and also to increase the coefficient of friction between the paper feed roller 6 and the recording paper 2, the surface of the paper feed roller 6 is
The surface is sanded to a roughness of 240 degrees, and the wrapping angle of the recording paper 2 around the paper feed roller 6 is set to about 70 degrees (as shown in FIG. 4) to ensure sufficient paper feeding force.

Next, a schematic plan view of the paper feeding device shown in FIG. 2, and FIG.
Pressing and release by the paper pressing means 7 will be explained using an exploded perspective view of the paper pressing means 7 shown in FIG.

As shown in these figures, the paper pressing means 7 includes an elastic eccentric shaft 7a, a bearing 7b pivotally supported by the eccentric shaft 7a, a cylinder 7c pivotally supported by the bearing 7b, and a cylinder 7c. The rubber 7d is attached to the rubber 7d. The bearing 7b is located inside both ends 7c1 and 7c2 of the cylinder 7c. A stainless steel pipe is used for the cylinder 7c to ensure sufficient rigidity. Further, the eccentric shaft 7a is made of an elastic body having a diameter such that the paper pressing means 7 can secure a predetermined pressing force. The bearing 7b is a rolling bearing and is disposed near the center of the paper pressing means 7, and makes the pressure distribution substantially uniform with respect to the paper feeding roller 6 which is pivotally supported at both ends.

FIG. 2(a) shows a state in which the paper pressing means 7 is released from pressing the paper feeding roller 6. Figure 2(b) is
A state in which the gear 12 fixed to the eccentric shaft 7a of the paper pressing means 7 is rotated approximately 180 degrees by the aforementioned gear 9 (shown in FIG. 1), and the paper pressing means 7 is pressing the paper feeding roller 6. shows.

The paper pressing means 7 presses the rubber 7d against the paper feed roller 6 by means of an eccentric shaft 7a, and the reaction force is applied to the bearing 7b.
acts on the eccentric shaft 7a through the axial direction, thereby deflecting the eccentric shaft 7a.

Next, paper insertion and paper conveyance will be described using the schematic side view of the paper feeding device shown in FIG.

The recording paper 2 fed from the paper feeding means 13 in FIG. 1 abuts against the paper pressing means 7 as shown in the paper feeding device in the released state of FIG. 4(a). Paper presser rotation transmitting means 14 made of an elastic material such as foamed urethane are inserted into both ends of the paper feed roller 6 (shown in FIG. 2), and are in weak pressure contact with the cylinder 7c of the paper presser means 7. Therefore,
As the paper feed roller 6 rotates in the direction of the arrow, the cylinder 7c and rubber 7d of the paper pressing means 7 rotate in the direction of the arrow, and the leading edge of the recording paper 2 is conveyed upward in the drawing. After the predetermined amount of transport, Figure 4(b)
As shown in FIG. 2, the eccentric shaft 7a of the paper pressing means 7 rotates approximately 180 degrees, and the rubber 7d comes into pressure contact with the paper feeding roller 6. At this time, the paper presser rotation transmitting means 14 made of an elastic material such as urethane foam comes into pressure contact with the cylinder 7c and becomes deformed. The recording paper 2 is not positioned near this paper presser rotation transmission means 14, but even if it were located, the paper feed force is extremely small compared to the paper feeding force of the rubber 7d of the paper presser means 7, which is the main paper feeding section. Because it is a power, there will be no trouble.

Furthermore, the paper conveyance speed when the paper feed roller 6 and the paper presser means 7 are released is determined by the paper feed roller 6, the paper presser rotation transmission means 14, the cylinder 7c of the paper presser means 7, and the rubber 7d.
The speed of the rubber 7d is increased by the approximate diameter ratio of each. Therefore, the recording paper 2 is inserted while being guided with its leading edge.

Furthermore, in this embodiment, the paper presser rotation transmission means 1
Although the case is shown in which the paper feed roller 4 is inserted into the paper feed roller 6, it can also be arranged independently so as to come into pressure contact with the paper presser means 7. At this time, the paper feed roller 6 does not need to rotate, but
Rotating it will make it easier to insert it.

[0019]

Effects of the Invention The present invention is composed of a paper feed roller, a paper presser, and a paper presser rotation transmission means, and by rotating the paper presser when paper is inserted, the recording paper can be easily maintained even on a curved paper conveyance path. It is possible to provide a highly reliable paper feeding device that allows smooth insertion and is free from paper jams.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a thermal transfer recording device incorporating a paper feeding device of the present invention.

FIG. 2 is a schematic plan view showing one embodiment of a paper feeding device.

FIG. 3 is an exploded perspective view of paper pressing means.

4 is a schematic side view showing the operation of the embodiment of FIG. 2; FIG.

FIG. 5 is a schematic side view showing a conventional example.

[Explanation of symbols]

1 Thermal transfer recording device 2 Recording paper 6 Paper feed roller 7 Paper pressing means 13 Paper feeding means 14 Paper presser rotation transmission means

Claims (4)

[Claims] 1. A paper feed roller that rotates by receiving a driving force, a paper presser that presses or releases the paper feed roller, and a paper presser rotation transmission device that transmits rotational force to the paper presser when released. A paper feeding device characterized by comprising: 2. The paper feeding device according to claim 1, wherein the paper conveying speed when the paper feeding roller and the paper pressing means are released is higher than that of the paper feeding roller. 3. The paper feeding device according to claim 1, wherein the paper presser rotation transmission means is made of an elastic body. 4. The paper feeding device according to claim 1, wherein said paper presser rotation transmitting means comprises an elastic body inserted into said paper feed roller and transmitting rotational force to said paper presser means.