JPS6222893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cut sheet feeding device used for feeding a sheet original in, for example, a copying machine. The purpose is to reliably detect that the final cut sheet is being sent out and the feeding status of the cut sheet.

The outline of a copying machine to which the apparatus of the present invention is applied will be explained below with reference to FIG. Copy machine main case 10
0 has a transparent document mounting table 1 in the upper opening 101, and the inside thereof is divided into two upper and lower chambers 103 by a partition plate 102.
It is divided into 104 sections. In the upper chamber 103, an illumination lamp 3 and a first movable mirror 4, which move forward from a home position indicated by a solid line to the left in the drawing at the same speed as the rotation speed of the photosensitive drum 8, are installed.
a second moving mirror 5 that moves forward at a speed of 1/2;
An optical system consisting of fixed mirrors 6 and 7 is arranged, and this optical system forms an image of the original O _B on the original table 1 on the image forming part 9 of the photosensitive drum 8. 2 indicates a document pressure bonding plate.

When the exposure is completed by a signal corresponding to the copy size, the illumination lamp 3 and movable mirrors 4 and 5 stop the forward movement a, and immediately move in the opposite direction, that is, back to the home position indicated by the solid line b, and then return to the reciprocating movement. Operations a and b are repeated according to the specified number of copies. When the designated number of copies are completed, the illumination lamp 3 and movable mirrors 4 and 5 stop at the home position indicated by the solid line and stand by. Note that the speed of the backward movement b is made faster than the speed of the forward movement a to increase copying efficiency.

The photosensitive drum 8 is, for example, a photosensitive layer coated with a transparent insulating layer, and is mounted in the upper right corner of the lower chamber 104 so as to be rotatable in the direction of the arrow on a shaft 8a. , primary charger 12, exposure simultaneous charger 14, full exposure lamp 1
5, developing device 16, transfer charger 20, separation static eliminator 2
1. Blade cleaner 2 having a blade 27a
7 is placed. The developing device 16 is a container 17
This is a powder developing device consisting of a developing roller 18 provided opposite the photosensitive drum 8 at a developer discharge port, and a blade 19 for making the amount of developer adhered to the surface of this developing roller uniform. It may be.

At the lower left of the lower chamber 104, several types of transfer paper storage cassettes 28 and a paper feed deck 29 are arranged according to the size of the transfer paper P, and a paper feed roller 3 is attached to each of them.
0,31 are provided. And cassette 28
Several pairs of rollers 32 and 3 are placed between the transfer charger 20 and the transfer charger 20.
2', 36/36', 37/37', guide plate pairs 34/34', 38/3 provided between each pair of rollers.
8', 40, 40', and 41, 41' constitute a transfer paper conveyance path. Further, a pair of guide plates 35 and 36' are provided between the paper feed deck 29 and the pair of rollers 36 and 36'.
35', 39' and 39', and a pair of rollers 33 and 33' provided between the two constitute a transfer paper conveyance path.

Copy paper P separated from photosensitive drum 8 after transfer
The belt 24 driven by the roller 23, the guide plate 25, and the pair of pressure rollers 42 and 4 of the fixing section 26
3. It is discharged onto a discharge tray 49 via a static eliminator 44, a pair of guide plates 45 and 46, and a pair of rollers 47 and 48. 50 is a cooling fan.

On the other hand, in the upper left part of the upper chamber 103, there is a sheet original insertion tray 55 of the sheet original auto feeder section.
and a sheet original discharge tray 71 are rotatably mounted on shafts 72 and 73. Both trays 5
When not in use, 5 and 71 can be folded down so that they are flush with the top of the case, as shown by the chain line, and can also be used as a workbench.

When both trays 55 and 71 are in the operating state shown by the solid lines in FIG.
1, 62, 65, 66, 69, 70, guide plate pairs 58, 59, 6 provided between each pair of rollers.
It is composed of 3, 64, 67, and 68.

The sheet document sent into the above-mentioned conveyance path by the pair of separation/feed rollers 56 and 57, which rotate in the directions of the arrows, respectively, has its leading edge detected by the detection element 60 and is temporarily stopped. Transported synchronously. When the guide plate 64 made of transparent glass passes through the position, it is exposed to light by the illumination lamp 52, and the light image is formed on the image forming section 9 via the fixed mirror 53, the mirror 54, and the fixed mirrors 6 and 7. It's getting old. Note that the mirror 54 mentioned above
is normally located at the position shown by the chain line, where it does not interfere with the reflected light from the mirror 5, and is moved to the position shown by the solid line in conjunction with, for example, moving the trays 55, 71 into use.

Normally, the number of sheet originals is not counted before being placed on the sheet original insertion tray 55 in the auto feeder section. For this reason, tray 55
It is necessary to determine and detect whether or not the last original sheet sent out is the last one, and to stop feeding the transfer material P based on this detection signal.

Conventionally, as the above-mentioned detection means, as shown in FIG. 2 (a linear development of the sheet document conveyance path in FIG. 1), a lamp 74 and a light receiving device are used to sandwich the tray 55 (including the sheet document placed thereon). The elements 75 are arranged opposite each other, or a microswitch is provided to act on the final sheet document. These detection means are provided inside the minimum length l ₁ of the usable sheet document.

Therefore, in the case shown in FIG. 2, if the length of the sheet original O _S is _l2 , it cannot be determined whether or not the final sheet original has been sent out until at least _l2 - _l1 of sheet originals have been fed out. Therefore, it is necessary to wait until the sheet original is sent out the above-mentioned distance before feeding the transfer paper. If the next transfer sheet is fed before then, one additional sheet will be fed. On the other hand, if the feeding of the sheet original and the transfer paper are related as described above, the copying interval becomes longer depending on the length of the sheet original, and for example, the number of copies per minute is drastically reduced, which reduces the value of the copying machine. This will reduce the

An object of the present invention is to reliably detect that the final sheet document has been sent out, regardless of the length of the sheet document, when the sheet document has been sent out a predetermined distance.

In order to achieve this object, the present invention is provided with a final cut sheet detection means 76 that detects that the final cut sheet is being fed out in response to the movement of the last cut sheet fed out from the tray.

This detection means 76, as shown in FIGS. 2 and 3,
Disk 78 with multiple holes 77 on the same circumference
and lamps 7 arranged opposite to each other with the disc 78 in between.
9 and a light receiving element 80. The disk 78 is rotatably attached to a shaft 82 perpendicular to the feeding direction of the sheet original O _S so that a portion of the disk 78 protrudes from the hole 81 of the tray 55 onto the tray surface. Further, the lamp 79 and the light receiving element 80 are housed in opposite legs 83a and 83b of the U-shaped case 83.

The sheet originals O _S on the tray 55 are sent out one by one from the top one by the separation/feeding rollers 56 and 57 as described above, but the disk 78 is not moved until the final sheet original is sent out. It never rotates. However, when the number of sheet originals on the tray decreases, the last one may be dragged and moved a little, so the disc 78 may move. However, since the movement in this case is small, a predetermined count number may be determined and if it is within the range, it may be determined that this is not the last sheet document feeding.

When the last original sheet is sent out, the circular plate 78 is rotated by the original sheet, and the light from the lamp 79 passes through the hole 77 and intermittently hits the light receiving element 8.
Enters 0. For this reason, a pulse signal is output from the light-receiving element 80, so this pulse signal is counted by a counter (not shown), and when a predetermined count is reached, it is determined that the final sheet original has been sent out, and the counter output is Therefore, feeding of the transfer paper, etc. is stopped.

Note that the detection means 76 may be of a type capable of detecting the movement of a driven member that is displaced following the movement of the final sheet document.

The present invention is configured so that when the final sheet original starts to be fed out from the tray as described above, the final sheet original detection means is activated by the movement of this sheet original, so that the last sheet original is sent out. It is possible to reliably detect the feeding status of the sheet original and the feeding status of the sheet original, and there is no inconvenience that the copying interval changes depending on the length of the sheet original unlike the conventional detection means. Further, the detection means can be freely provided at any position in the sheet original traveling direction as long as the length is within the minimum size of the sheet original, so the design is extremely easy.
Furthermore, if the detection means in the illustrated example detects the last sheet when the number of pulse signals from the light receiving element reaches a predetermined value, it is possible to detect the last sheet even in a place where outside light is likely to be picked up. It has the advantage of being able to be carried out accurately.

Note that the present invention has the following features in its embodiments.

1. The detection means must be within the minimum size sheet document placement surface.

2. The detection means detects the displacement of the driven member via the driven member that is displaced in accordance with the movement of the final sheet document.

3. The driven member is a rotating body.

It should be noted that the present invention can be applied not only to the field of copying machines as shown in the drawings but also to all fields where cut sheets are used.

[Brief explanation of the drawing]

FIG. 1 is a front view of a copying machine to which the present invention is applied, with the front panel removed, FIG. 2 is an enlarged front view of the present invention, and FIG. 3 is a perspective view showing one example of the detection means. be. 55 is a sheet original insertion tray, 56 and 57 are separating and feeding rollers, 76 is a detection means, 77 is a hole, 7
8 is a disk, 79 is a lamp, 80 is a light receiving element, 81
is a hole, and O _S is a sheet manuscript.

Claims (1)

[Scope of Claims] 1. A tray 55 for stacking cut sheets, feeding means 56 and 57 for feeding the cut sheets on the tray one by one, and a final cut sheet for detecting movement of the last cut sheet sent out from the tray. A cut sheet feeding device comprising: a cut sheet detection means 76;