JPH03288735A - Automatic paper feeding device - Google Patents

Abstract

PURPOSE:To improve the pressing position precision by connecting a paper feeding roller with a pad holder fixed on the device body through a connecting arm and turning the connecting arm, having the installation part with the holder as fulcrum. CONSTITUTION:One edge 32a of a connecting arm 32 is held in rotatable manner at both edges of the rotary shaft 31 of a paper feeding roller 30, and the other edge 32b is installed in rotatable manner on a pad holder 40 fixed on a body, by a shaft 33. Accordingly, the arm 32 is freely turned around the shaft 33. The arm 32 is pressed by a spring 44, and the paper feeding roller 30 contacts a friction pad 41 held on the holder 40. Accordingly, the paper feeding roller 30 and the friction pad 41 can be always pressed at a constant position by an arm 22, and the top edges of the low-lying paper sheets which are driven out overlapping each other pass through a gap 45 and surely contact with the edge surface 42a, and the double feed is surely prevented.

Description

[Detailed Description of the Invention] Industrial Field of Application This invention is applicable to recording devices such as printers, copiers, facsimile machines, and printing machines that use paper to record information such as printing, transferring, copying, printing, etc. obtain.

More specifically, the present invention relates to an automatic paper feeder that automatically separates and automatically feeds stacked sheets one by one from the top in such a recording apparatus.

2. Description of the Related Art Conventionally, in this type of automatic paper feeder, as shown in FIG. There is a structure in which a pad holder 4 holding a paper feed tray 5 is attached via a spring 6 to press the friction pad 3 against a paper feed roller 1. In other automatic paper feeding devices, as shown in FIG. 7, for example, a paper feeding roller 1 is held via a support shaft 2 whose both ends are inserted into guide holes (not shown) provided in a side plate (not shown). At the same time, paper feed 1
- When the lay 5 is attached, the friction pad 3 is pressed through the levers 7 and 8, and the paper feed l~lay 5 is pressed.
There is also a structure in which the paper feed roller 1 is held in a state in which the friction pad 3 is released from the friction pad 3 via the levers 7 and 8 when the paper feed roller 1 is pulled out (see Japanese Patent Laid-Open No. 62-56227).

And, those conventional automatic paper feeding devices have paper feeding roller 1
The paper P stacked in the paper feed tray 5 is fed out by rotating, and the paper P is automatically fed out while being separated one by one from the top by friction with the friction pad 3.

Problems to be Solved by the Invention By the way, in this automatic paper feeder, in order to stabilize the paper separation performance and reliably prevent double feeding of paper, the paper feed roller 1 must be placed on the surface of the friction pad 3 at a fixed position. It is necessary to accurately install both in a predetermined position so that they are in contact with each other. However, among the conventional automatic paper feeders described above, in the former configuration, the paper feed roller 1 is supported by the side plate, while the pad holder 4 is supported by the paper feed 1 tray 5; A paper roller 1 is supported by a side plate, and a pad holder 4 is supported by a holding frame 9. Therefore, in the conventional structure, the paper feed roller 1 and the pad holder 4 are supported by separate support members, so it is difficult to provide the paper feed roller 1 and the friction pad 3 with good relative positional accuracy. Therefore, there was a problem in that the paper separation performance in the automatic paper feeder was unstable and double feeding of paper could not be reliably prevented.

SUMMARY OF THE INVENTION An object of the present invention is to improve the positional accuracy of the paper feed rollers and friction pads in the automatic paper feeder described above, stabilize the paper separation performance, and reliably prevent double feeding of paper sheets.

Means for Solving the Problems Therefore, the present invention as set forth in claim 1, for example, as shown in the illustrated embodiment below, holds a friction pad 41 with a pad holder 40 and presses a paper feed roller 30 against it. In the automatic paper feeder 20 of the recording apparatus, the stacked paper 18 is fed out by rotating the paper feed roller 30, and the paper is separated one by one from the top by friction with the friction pad 41 and is automatically fed out. The pad holder 40 is fixed to the main body of the recording apparatus, the pad holder 40 and the paper feed roller 30 are connected by a connecting arm 32, and the connecting arm 32 is connected to the pad holder 40 by a support shaft 33 or the like. It is characterized in that it is rotatable about the mounting part as a fulcrum and is movably provided between a pressing position where the paper feed roller 30 is pressed against the friction pad 41 and a retreat position where the pressing is released.

Further, as shown in the illustrated embodiments below, in the invention as set forth in claim 1, when the paper feed tray 17 is not installed, the connecting arm 32 to bring the paper feed roller 30 to the retracted position, and when the paper feed tray 17 is installed, the operating arm 51 is pushed by the paper feed tray 17 and rotates against the rotational behavior. The actuating arm 51 and the connecting arm 32 are connected, and as the actuating arm 51 rotates against the rotational habit, the connecting arm 32 is rotated to push the paper feed roller 30. It is characterized in that a spring such as a tension spring 53 is provided as a contact position.

Function And, in this invention according to claim 1, the paper feed roller 30
The paper 18 is sent out by rotating. When the paper 18 jams during paper feeding, the connecting arm 32 is rotated as appropriate to move the paper feeding roller 30 to a retracted position where the pressing is released.

Further, in the present invention according to claim 2, the paper feed tray 17
When feeding paper with the paper feeding tray 17 mounted, the actuating arm 51 is rotated in one direction against the rotational behavior of the paper feeding tray 17.
Furthermore, along with this, the paper feed roller 3 is rotated by a spring.
0 to the pressing position. When the paper 18 jams during paper feeding, when the paper feed tray 17 is pulled out, the operating arm 5
1 in the other direction based on its rotational behavior to feed paper roller 3.
0 to the retreat position.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 5 shows a schematic structure of the internal mechanism of a laser printer equipped with an automatic paper feeder, which is an embodiment of the present invention. The reference numeral 10 in the figure is the main body of the apparatus. Inside the apparatus main body 10, a drum-shaped photoreceptor 11 is provided at the center. Around the photoreceptor 11, a charger 12 on the lower side is connected to the photoreceptor 11.
In order of rotation direction (counterclockwise) of No. 1, the right developing device 13
, the transfer device 14 on the upper side, and the cleaning device 15 on the left side are arranged. An optical writing device 16 is provided below the transfer device 12, the developing device 13, and the cleaning device 15. Further below the optical writer 16, a paper feed tray 17 is removably loaded. Paper 18 is stored in the paper feed tray 17 . On the right side of the developing device 13, there is provided a paper feed path 21 that guides the paper 18 sent out from the automatic paper feeder 20 according to the present invention upward. There is a manual paper feed slot 2 at the end of the paper feed path 21.
A paper conveyance path 23 common to the paper 18 inserted from 2 is provided, and the paper 18 is guided to the photoreceptor 11. Paper transport path 2
3, a pair of registration rollers 24 is arranged. On the other hand, the above-mentioned transfer device 12 is sandwiched between the pair of registration rollers 24.
A conveyor 25 is provided on the opposite side, and a fixing device 26 is further provided beyond that. On the left side of the fixing device 26,
Install the paper ejection tray 27.

However, when recording by electrophotography using the laser printer, the automatic paper feeder 20 is driven to separate the sheets 18 from the paper feed tray 17 one by one and automatically feed them into the paper feed path 21. send out to target. Alternatively, the user can switch and manually feed the paper 18 from the manual paper feed slot 22. Then, the paper 18 fed from the automatic paper feeder 20 or the manual paper feed port 22 eventually hits the leading end of the paper against the pair of registration rollers 24 and is stopped.

7- On the other hand, the photoreceptor 11 rotates counterclockwise in the figure,
The surface is uniformly charged with the charger 12, and then an electrostatic latent image is formed on the surface by irradiating laser light with the optical writer 16, and then when it passes through the developer 13, the electrostatic latent image is are sequentially visualized using toner. Then, in synchronization with the image, the paper 18 that had been in contact with the pair of registration rollers 24 described above is sent out toward the photoreceptor 11. The image on the photoreceptor 11 is then transferred onto the paper 18 by the transfer device 14. After the transfer, the residual toner on the photoreceptor 11 is scraped off by a cleaning blade 28 of the cleaning device 15 and collected into a collection tank 29. Subsequently, the charge remaining on the photoreceptor 11 is removed by a static eliminator 30.

On the other hand, the paper 18 is sent to a fixing device 26 by a conveyor 25, and the transferred image is thermally fixed by the fixing device 26. Thereafter, the sheets 18 are sent out and stacked one after another on the sheet discharge tray 27.

By the way, the above-mentioned automatic paper feeder 20 is specifically
It is constructed as shown in the figure and FIG.

8- Reference numeral 30 in the figure is a paper feed roller, which is provided on the rotating shaft 31. Both ends of the rotating shaft 31 are connected to one end 32a of the connecting arm 32.
to hold it freely in rotation. The connecting arm 32 is rotatably attached to the support shaft 33 at the other end 32b. The other end of a compression spring 34 whose one end is attached to a suitable fixing member within the apparatus main body 10 is pressed against the connecting arm 32 to give it a habit of constantly rotating counterclockwise in the figure about the support shaft 33. The support shaft 33 is
Both ends thereof are fixed to side plates 35 and 36, and an idler gear 37 is rotatably attached to the negative end side (right side in the figure). The idler gear 37 meshes with the gears 38 and 39 and transmits the rotation of a drive motor (not shown) to enable the paper feed roller 30 to rotate. Then, this paper feed roller 30 is placed in the pad holder 4.
The paper 18 is pressed against the friction pad 41 held above the sheet 0 and the uppermost sheet 18. The friction pad 41 includes a fixed pad 42 provided on the downstream side (right side in the figure) of the pad holder 40 in the paper conveyance direction, and a movable pad 43 provided on the upstream side thereof. The fixed pad 42 forms an edge surface 42a on the movable pad 43 side. Then, a paper feed roller 30 is pressed against the surface. On the other hand, the movable pad 4
3 is attached onto a leaf spring 44 which is bent and provided in the recess 40a of the pad holder 40. And the leaf spring 44
to press the upper edge of the fixing pad 42 side against the paper feed roller 30. Then, a certain gap 45 is left between the upper edge and the edge surface 42a, and the paper feed roller 3
0 is placed at the pressing position shown by the solid line in the figure.

Then, as shown in FIG. 3, the paper feed roller 30 is rotated counterclockwise as shown by the arrow in the figure to remove the paper from inside the paper feed tray 11.
Roll out 8. At this time, if two sheets of paper 18 are fed out as shown in the figure, the leaf spring 44 is bent and the paper 18 passes between the paper feed roller 30 and the movable pad 43 and passes over the upper sheet 18a. If the lower paper 18b passes between the paper feed roller and the movable pad 43, it passes through the gap 45 as shown in the figure, and the edge surface 4 of the fixed pad 42
Hit 2a and stop. In this way, the upper paper 18
Only a is brought into close contact with the paper feed roller 30 by the biasing force of the leaf spring 44, guided between the paper feed roller 30 and the fixed pad 42, and sent out through between the paper feed roller 30 and the fixed pad 42. Then, the lower paper 18b is brought into close contact with the paper feed roller 30 and guided between it and the fixing pad 42, and similarly sent out through the gap therebetween. Thereby, the stacked sheets 18 can be separated one by one from the top and automatically sent out. On the other hand, if the paper 18 jams during paper feeding, for example, operate the operating lever as appropriate to rotate the connecting arm 32 clockwise in FIG. , and move to the retracted position shown by the dotted line in the figure.

In this invention, since the paper feed roller 30 is connected to the same pad holder 40 to which the friction pad 41 is attached by the connecting arm 32, the paper feed roller 30 and the friction pad 41 can be provided with high positional accuracy relative to each other. For example, in this illustrated embodiment, the paper feed roller 30 is positioned so that it hits the friction pad 41 at a predetermined pushing position in which the size of the gap 45 into which the lower paper 18b enters is constant. be able to. Therefore, the leading ends of the lower sheets 18b that are fed out in an overlapped manner pass through the gap 45 and reliably strike the edge surface 42a, so that double feeding of the sheets 18 can be more reliably prevented.

By the way, in the illustrated embodiment described above, the paper feed roller 3 is always
0 is the pressing position, and when the paper 18 jams, it is configured to be moved to the retracted position manually such as by operating a lever.

However, in the present invention, as shown in FIG. 4, for example, the paper feed roller 30 is placed in the retracted position when the paper feed tray 17 is not installed, and the paper feed roller 30 is automatically placed in the pressed position when it is installed. , the paper feed roller 3 depending on the attachment/detachment of the paper feed tray 17.
0 can also be configured to be freely movable between a pressing position and a retracted position with respect to the friction pad 41. That is, in this other embodiment, a V-shaped actuation arm 51 is attached to the shaft 50 supported by the side plate. The actuating arm 51 is rotatably provided about its shaft 50 as a fulcrum.

One end 52-1a is biased by a compression spring 52 to provide a constant rotational habit in the clockwise direction in the figure. When the paper feed tray 17 is not attached, the other end 51b is abutted against the connecting arm 32, and the connecting arm 32 is rotated to move the paper feed roller 30 to the retracted position shown by the chain line in the figure. It is stopped and held at the retracted position with an appropriate stopper. The other end 51b of this actuating arm 51 and the connecting arm 32 are connected by a tension spring 53.

However, when the paper feed tray 17 is installed as shown in the figure, the front plate portion 17a of the paper feed tray 17 presses against one end 51a of the actuating arm 51, and the actuating arm 51
is rotated counterclockwise as shown by the arrow in the figure against the compression spring 52. Then, the connecting arm 32 is pulled and rotated by the tension spring 53, and the paper feed roller 30 is moved to the paper feed tray 1.
7 to a pressing position where it is pressed against the paper 18 and the friction pad 41. However, the paper feed roller 30
The paper 18 is sent out by rotating. In addition, when the paper 18 jams during paper feeding, if the paper feed tray 17 is pulled out, the biasing force of the compression spring 52 rotates the actuating arm 51 to rotate the connecting arm 32 and rotate the paper feed roller 30. Automatically moves to the evacuation position.

Therefore, according to the other illustrated embodiment, the paper feed roller 30 is automatically movable between the pressing position and the retracted position in accordance with the insertion and removal of the paper feed tray 17, so that jammed paper can be easily removed. be able to.

Effects of the Invention Therefore, according to the present invention, since the paper feed roller is attached to a fixed pad holder via a connecting arm, the positional accuracy of the paper feed roller and friction pad is increased, and paper separation performance is stabilized. Therefore, double feeding of sheets can be reliably prevented.

[Brief explanation of the drawing]

Figure 1 is a block diagram of an automatic paper feeder that is an embodiment of the present invention, Figure 2 is a plan view of the automatic paper feeder, Figure 3 is an explanatory diagram of the operation of the automatic paper feeder, and Figure 4. 5 is a block diagram of an automatic paper feeder according to another embodiment of the present invention, and FIG. 5 is an overall schematic diagram showing the internal mechanism of a laser printer equipped with the automatic paper feeder. FIG. 6 is a block diagram of a conventional automatic paper feeder in which the paper feed roller is fixed, and FIG. 7 is a block diagram of another conventional automatic paper feeder in which the paper feed roller is movable. 18......Paper 20...Automatic paper feeder 30...Paper feed roller 32...Connection arm 40. ......Pad holder 41...Friction pad 51...
...Actuation arm

Claims (1)

[Claims] 1. Hold a friction pad with a pad holder, press a paper feed roller against it, rotate the paper feed roller to feed out the stacked paper, and the friction with the friction pad causes the paper to be drawn out from above. In an automatic paper feeding device of a recording device that automatically feeds sheets while separating them one by one, the pad holder is fixed to the main body of the recording device, and the pad holder and the paper feeding roller are connected by a connecting arm. The automatic paper feeder is configured to rotate about an attachment part to the pad holder as a fulcrum and to be movable between a pressing position where the paper feeding roller is pressed against the friction pad and a retreat position where the pressing is released. Device. 2. When the paper feed tray is not installed, the connecting arm is rotated based on rotational behavior to bring the paper feed roller to the retracted position;
When a paper feed tray is attached, an operating arm is provided that is pushed by the paper feed tray and rotates against the rotational behavior, and the operating arm and the connecting arm are connected to control the rotational behavior of the operating arm. 2. The automatic paper feeder according to claim 1, further comprising a spring that rotates the connecting arm in response to rotation of the paper feed roller to the pressing position.