JPH03284556A - Automatic paper feeder - Google Patents

Abstract

PURPOSE:To surely and quickly discharge recording paper, with its obverse and reverse set reversely, to a paper box by driving a paper return roller, which is rotated in a press contact with a feed roller, through a slip mechanism and a pause mechanism. CONSTITUTION:A torque limiter 11, in which torque is smaller than friction force between paper return roller 2 and a paper feed roller 3 at the time of feeding a single sheet of recording paper and larger than at the time of a double feed, and a pause mechanism 9B, performing no transmission within a predetermined rotational angle, are provided in a rotation transmitting system reaching the paper return roller 2 from the paper feed roller 3 rotated in a direction equal to a feed roller 1. Highness of processing efficiency is contrived by preventing the double feed of recording paper by action of the torque limiter 11 and also discharging the reverse obverse/reverse recording paper, detected by an obverse/reverse discriminating sensor provided in a recording paper part side, surely to a side of a paper box 15 without detaching the paper return roller 2 from the feed roller 1 by action of the pause mechanism 9B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an automatic paper feeder having a multilayer feeding prevention mechanism that sequentially feeds stacked recording sheets to a recording section.

[Prior Art] An example of an automatic paper feeder having a multi-layer feeding prevention mechanism is one that has a slip mechanism as disclosed in Japanese Patent Application Laid-Open No. 136444/1983.

The present invention relates to this rare improvement. As an example of the horizontal orientation of this type of feeder, for example, in the case of a thermal melting type thermal transfer printer, if paper with a smooth backing is used as the recording paper, printing quality will not be particularly affected even if the recording paper is fed with the front side reversed. However, especially when applied to dye-sublimation thermal transfer printers used for image signal output, the surface of the recording paper is also coated with a special coating for print quality, so it may be possible to accidentally damage the back side of the recording paper. When printing, the ink ribbon adhered to the recording paper and could not be peeled off, causing jamming of the ink ribbon and potentially damaging the machine. Therefore, in this type of printer, it is necessary to provide a mechanism for detecting the front and back sides of the recording paper, and to return the recording paper to the paper box when the recording paper is fed with the front and back sides reversed. In the case of the mechanism disclosed in the above publication, the paper return roller is once separated from the paper feed roller, and the recording paper is returned to the paper box by the frictional force between the recording paper and the paper return roller due to the weight of the recording paper. Since there is only a very small frictional force due to the paper's own weight, the return operation becomes unstable and there is a risk that the recording paper may jam.

Further, as disclosed in JP-A No. 64-2951, a paper return lever is provided in the automatic paper feeder, the recording paper is pressed against the paper return roller via the paper return lever, and the recording paper is placed in the paper box by reversing the roller. A mechanism for returning it has also been proposed, but
The lever is required only for paper ejecting operation, which requires space in terms of number of parts, and is complicated and expensive. Its purpose is to remove recording paper that is set upside down in a paper box. ! To provide an automatic paper feeder that can reliably and quickly return paper to a paper box without causing jamming using a unique mechanism.

[! Ili! [Means for Solving the Problems] Specifically, the stacked recording paper is fed between a feed roller and a paper return roller that rotate in pressure contact with each other as the paper feed roller rotates, Further, the paper feed roller and the feed roller are formed to be able to rotate in the same direction, and the paper return roller 5 is configured to rotate in the same direction.
When feeding a sheet, it follows the rotation of the feed roller and rotates forward in the feeding direction via a slip mechanism, and when feeding multiple sheets of paper, the lower sheet is ejected to the paper box side by reverse operation. A stop mechanism is provided to prevent the paper return roller, which is in pressure contact, from rotating in the paper feeding direction within a certain rotation angle, with the paper return roller having a recording paper front/back discrimination sensor and being in pressure contact with the feed roller which is driven in reverse by the back discrimination signal. was formed.

[Function] According to the above configuration, in the operation of returning the fed paper to the paper box based on the paper back side discrimination signal, there is no need to move the paper return roller N distance from the feed roller as in the conventional example, and it is not necessary to move the paper return roller N distance from the feed roller as in the conventional example. Paper can be ejected efficiently and reliably. In particular, when the lower paper is ejected by the reverse drive of the paper return roller in the multi-layer feeding prevention operation, this paper is located near the paper return roller, but in this state, the paper is ejected according to the back side discrimination signal. Even if the operation is performed, the pause mechanism is melted so that the paper return roller itself does not generate a driving force within a certain rotation angle to pull the paper located in the vicinity in the paper feeding direction, and as a result, the slip mechanism is The paper discharge operation is performed by following the reverse rotation of the pre-delivery roller.

[Embodiment] An embodiment of the automatic paper feeder of the present invention will be described below with reference to FIGS. 1 to 7.
This will be explained based on the diagram. FIG. 1 is a perspective view of the device, and FIG. 2 is a schematic side view. 1 is a feed roller; 2 is a paper return roller; and 3 is a paper feed roller. It is arranged so that it can rotate freely. The paper return roller 2 is rotatably supported by a support frame 4 via bearings, and the frame 4 is supported by pins 6A and 6B implanted in side frames 5A and 5B.
By forming it so that it can swing around the center, it is formed so that it can be pressed against and released from the delivery roller 1. In the non-feeding state, as shown in FIG. 2, the spring 7 and the stopper 8 keep the feed roller 1 and paper return roller 2 in an open state. Paper return roller 2
The paper feed roller 3 is formed so that the shaft end on the side frame 5B protrudes outward from the frame and can be interlocked with the pulleys 9 and 10 disposed in the armpits via a belt 14. Furthermore, the pulley 10 is formed to interlock with the paper return roller 2 via a known torque limiter (slip 1111).The side frame 5B has a support frame for mounting the paper return roller. 4, the paper return roller shaft 2A protrudes outward from the side frame 5B, so as not to interfere with the swing operation of the paper return roller shaft 2A protruding outward from the side frame 5B. The feed roller 1 and paper feed roller 3 have a feed roller gear 24 and a paper feed roller gear 12 that rotate integrally with the roller shafts IA and 3A, and an intermediate gear is connected between the two gears. By forming the rollers 1.3 to interlock with each other at 25, both rollers 1.3 are formed to always rotate in the same manner when a drive is transmitted from a paper feed motor (not shown) to the wheel train.On the other hand, the pulley 9 and the paper feed roller 3, for example, as shown in FIG.
The side frame 5B of A is formed so that it can rotate integrally by fitting the paper feed roller gear 12 to the irregularly shaped shaft portion projecting outward. Reference numeral 13 denotes a drive transmission pin that serves as a medium for transmitting rotational force to the pulley 9, and the gear projection 12A and the receiving hole 9A of the pulley 9 rotatably disposed on the paper feed roller shaft 3A. At the time of overlapping arrangement, the drive transmission bottle 13 is arranged so as to be located in a notch 9B extending from the receiver 9A and extending outward from the pulley,
In addition, the stop ring 26 prevents the above-mentioned components from coming off the shaft, and the stop ring 23 also locks the end of the shaft that projects outward from the side frame 5A. Due to rotation transmission from the paper feed motor (not shown), the drive transmission pin 13 of the paper feed roller gear 12 is positioned within the notch 9B of the 1-lead 9, and in the state shown in FIG. 4, the paper feed roller gear 12 is moved in the direction of the arrow. When rotated, the drive transmission bin 13 abuts and engages with the opposite wall of the notch 9B with an angular difference (time lag) of 5 rotation angles a, thereby rotating together with the paper feed roller 3. Reference numerals 21 and 22 indicate bearings disposed on the side frames 5A and 5B. 15 is a paper pocket; 17 is a stack of recording paper on the bottom plate 16 of the paper box 15; 18 is a push-up lever; this lever 18, which is elastically supported when the recording paper 17 is fed, handles the force exerted by cam control or the like; In the transmission mechanism (not shown), pin 19
is used as a swinging fulcrum to pass through the opening 15A of the paper box 15 and lift the bottom plate 16 upwards (in the direction of arrow A), thereby bringing the topmost stacked recording paper into contact with the paper feed roller 3. It is. During the paper feeding operation, in addition to the operation by the push-up lever 18, the paper return roller 2 is attached to the feed roller 1 by a swinging motion (in the direction of the arrow) using the bin 6B of the support frame 4 as a swinging fulcrum. Pressure contact. When the feed roller 1 and the paper return roller 2 are separated from each other as shown in FIG. The paper return roller 2 is also formed to rotate in the same direction via the belt 14 while rotating synchronously. Further, the torque of the torque limiter (slip mechanism) 11 disposed between the two paper return roller shafts and the pulley 10 is equal to the frictional force between the paper return roller 2 and the feed roller 1 when there is no paper. , or the frictional force between the recording paper and the paper return roller when two or more sheets of recording paper are fed, which is smaller than the frictional force between the recording paper and the paper return roller when two or more sheets of recording paper are fed. It is set to be greater than the frictional force.
20 is the feed roller 1 and the paper return roller 2;
This is a sensor for determining the front and back sides of the recording paper fed through the roller 1.2, and is disposed on the recording unit side of the roller 1.2, for example, when the identification mark on the fed recording paper is at a predetermined position. The automatic paper feeder of the present invention having a configuration of 0 or more, which is performed by determining whether or not
The operation effect will be explained based on the figure. FIG. 5 shows a state in which one sheet of recording paper is being fed.
24), the feed roller 1 and the paper feed roller 3 rotate synchronously in the same direction. In this state, as the push-up lever 18 swings, the uppermost recording paper that is in pressure contact with the paper feed roller 3 is fed forward. The paper return roller 2, which is swing-controlled along with the above operation, is attached by the operation of the support frame 4, and the paper return roller 2 presses against the drive-rotating feed roller 1 and rotates as a result. The paper is fed to the recording unit side by the paper feeding operation. The paper return roller 2 rotates in the same direction as the paper feed roller 3 in conjunction with the belt in the no-load state shown in FIG. slip mechanism) 1
In the state shown in FIG. 5, the feed roller 1 is rotated by the rotation of the feed roller 1 (in the direction of the arrow A) against the rotation direction of the pulley 10 (in the direction of the arrow A) via the roller 1. When the paper front/back discrimination sensor 20 outputs a back-side discrimination signal, the feed roller 1 and the paper feed roller 3 rotate in reverse, and the paper return roller 2 rotates following the feed roller 1, so that the fed recording paper is The paper is discharged to the paper box 15 side. FIG. 6 is a diagram for explaining a mechanism for preventing multilayer feeding when recording paper is fed in multiple layers. When the topmost recording paper pressed against the paper feed roller 3 is fed forward, two or more sheets may be fed along with the topmost recording paper due to the influence of static electricity. In this case, the paper return roller 2, which rotates as a result of the drive rotation of the feed roller 1 (in the direction of the arrow), simultaneously guides the second multi-layered recording paper and generates a force greater than the frictional force between each paper. Due to the action of the torque limiter (slip mechanism) 11 in the membrane chamber, the second sheet of multi-layered recording paper is driven to rotate in the same direction as the paper feed roller 3 which is interlocked with the belt (in the direction of arrow A). It is discharged to a position where it leaves the return roller 2. When there is only one sheet of recording paper, the fifth
In the figure, as explained above, the two paper return rollers follow the drive rotation of the feed roller 1 (in the direction of the arrow).
The recording paper is sent M toward the recording section. Even if there are two or more sheets of recording paper that have been fed in layers, they are sequentially ejected in the above operation. In the state shown in FIG. 6, when the uppermost recording paper is fed after the stacked recording paper is ejected, a back side discrimination signal is output from the paper front/back discrimination sensor 20, as shown in FIG. As shown in FIG. 2, the recording paper is discharged into the paper box 15 by the reverse rotation of the feed roller 1 and the paper feed roller 3. At the same time as the paper feed roller 3 reverses, a paper return roller 2 rotates in reverse in conjunction with a belt.
are formed so as to prevent the multilayer fed recording paper located near the paper return roller 2 from being fed in the feeding direction at the same time as the topmost recording paper is ejected by interlocking with each other with a certain time lag. Become. Specifically, the third
As shown in the figure, the interlocking relationship between the pulley 9 and the paper feed roller gear 12 is such that the drive rotation of the paper feed roller gear 12 for feeding the recording paper to the recording unit side moves the recording paper toward the paper box 15 side. Since no rotational driving force is applied to the paper return roller 2 while the paper is being ejected to the 10 slips and rotates via a torque limiter (slip mechanism) 11, and the paper return roller 2 is driven to rotate, thereby ejecting the paper. Note that the distance between the paper return roller 2 and the paper feed roller 3 may be interlocked by a gear instead of a belt, and on the other hand, with a difference (time lag), the drive transmission pin 13 of the paper feed roller gear 12 is connected to the notch 9B. The belt 14 rotates together with the paper feed roller gear 12 by contacting and engaging with the opposite wall of the belt 14 .
The driving rotational force to the pulley 10 interlocked with is transmitted with the rotation angle difference (time lag).

When switching to reverse operation in this way, in this embodiment, the paper return roller 2 is interlocked with the belt after the time lag described above, and the method of transmission is arbitrary, and the time lag can be removed. For example,
As shown in FIG. 8, an angular play may be provided between the cotter pin 31 press-fitted into the shaft 30 of the paper feed roller and the pulley 32 so that rotation can be transmitted.
As shown in the figure, the pulley itself consists of three parts, 33A3
A pulley 33A formed of 3B and arranged so as to be rotatable on the shaft 34 of the paper feed roller 7-Lee 33
B may be formed to have angular play so as to be able to transmit rotation, and the angular play and slip mechanism may include
Although this is an example in which the paper feed roller and the paper return roller are formed separately, their arrangement may be reversed, or furthermore, one may have both functions, and these combinations and modifications change the gist of the present invention. It's not a thing.

[Effects] As described above, according to the automatic paper feeder of the present invention, this is performed by the feed roller and the paper feed roller, which reverse in the paper ejection direction in response to the back side discrimination signal from the paper front/back discrimination sensor. 1 to 7 show an embodiment of the automatic paper feeding device of the present invention, FIG. 1 is a perspective view showing the structure of the device, and FIG. 2 shows the device in FIG. 1 as viewed from the left side. Fig. 3 is an exploded view showing the structure of a part of the paper feed roller, and Fig. 4 is a side view of the paper feeding roller shown in the drawing. A side view showing the relationship with the drive bin, Figure 5. By using a simple device formed so that the driving force is transmitted with a time lag, the paper return roller is separated from the feed roller as in the conventional example during this operation. There is no need to do so, and the recording paper can be reliably ejected to the paper box by following the reverse drive operation of the delivery roller while still in pressure contact, resulting in higher efficiency in nuclide processing and improved reliability as a device. It has this effect.

1...Feeding roller 2...Paper return roller 3...Paper feed rollers 9, 10...Pulley 9B...Notch 11...
・・Torque limiter (slip mechanism) 13 ・・Drive transmission bin 20 ・・Paper front/back discrimination sensor Fig. 4

Claims (1)

[Claims] The stacked recording paper is configured to be fed to the recording unit by being guided between a feed roller and a paper return roller that rotate under pressure due to pressure rotation of a paper feed roller, and a space between the two rollers. When feeding multiple layers of paper to
In an automatic paper feeder equipped with a multi-layer feeding prevention mechanism, the paper return roller, which is rotated by the feeding roller through a slip mechanism, is reversely rotated to eject the multi-layer fed paper to the paper feed roller side. A recording paper front/back discrimination sensor is arranged on the recording unit side of the rotating feed roller and paper return roller, and the paper return roller itself is driven and rotated in the feeding direction while the feed roller is driven in reverse upon detecting the back side. An automatic paper feeding device characterized by forming a pause mechanism for stopping the paper within a certain rotation angle to prevent