JPS59217536A - feeding device - Google Patents

Abstract

PURPOSE:To make a feeder device in small size by furnishing a means to hold an exhausted sheet pressed to a feeder roller and to separate all other above lying sheets from it. CONSTITUTION:When a sheet P1 exhausted separatedly from the undermost lying one of a bundle of sheets P contained heavily with the aid of a weight has attained such a state as held by a transport roller couple 10 on the way of transportation and transported, all other sheets in stack plus the weight are separated from this held sheet so as to eliminate increment of the load on the transport roller couple 10 otherwise caused by the weight of these sheets plus weight. Accordingly the system requires only small-sized transport rollers having a weaker transporting force, to contribute to compacting the space for transport of sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a feeding device suitable for use in image forming apparatuses and the like.

A feeding device configured to store a large number of sheets in a stack in a container and take out one sheet at a time starting from the bottom of the sheet bundle is conventional, especially in feeding devices that process relatively thick sheets. Various proposals have been made.

FIG. 1 schematically shows an example of the above-mentioned feeding device used in an image forming apparatus such as a copying machine. There is a sheet P to be processed in the cassette C.
are stored in piles.

The cassette C is placed on a stand 3 in the image forming apparatus.
A long hole 2 extending in the sheet running direction is formed in the bottom surface of the sheet.

A long hole 3a is formed in the side wall of the platform 3, and a shaft 6, on which a one-way clutch 7 is attached and a feed roller 5 is mounted, is loosely fitted into the hole so that it can only slide. The one-way clutch 7 is mounted so as to rotate the feed roller 5 only in the direction of the arrow in FIG.

The shaft 6 is also loosely fitted into an elongated hole 4a formed in the free end side of an arm 4, which is pivotally connected to a five-digit pin 4b at a suitable position in the image forming apparatus, and the arm 4 is connected to a slot 4a as shown in the figure. A spring 8 gives it a biasing tendency to the right, and a solenoid 9 allows it to swing against the action of the spring 8.

When the solenoid 9 is deenergized, the arm 4 and the roller 5 etc. pivotally attached to it are at the position indicated by the chain line CE in the figure.
It is maintained by the action of a spring 8, and the feeding roller 5 is in close contact with the surface of the lowermost sheet in the cassette via the elongated hole 2. When the image forming apparatus is activated and the solenoid 9 is energized at a predetermined time in synchronization with other internal mechanical parts, the arm 4 rotates counterclockwise in the figure against the action of the spring 8. As a result, the feeding roller 5 frictionally engages with the sheet surface and moves the sheet to the left in the figure.

A gap 1a is formed at the lower end of the front edge of the cassette C in the paper advancing direction, allowing only one sheet to pass through, so only the bottommost sheet is ejected from the cassette. The material 1 is then conveyed through a conveying path 11 to a pair of conveying rollers 10, where it is actively gripped and further conveyed to the next process position.

When the solenoid 9 is deenergized after a predetermined period of time, the clutch 7 of the lever 4, feed roller 5, etc. is released again by the action of the spring 8, and the feed roller 5 rotates freely, so that the rollers are renewed. It does not affect the sheet brought to the bottom surface.

By the way, in a feeding device having such a configuration, since the sheet bundle is discharged from the bottom side, the moving sheet has the weight of all the sheets above it, as well as the weight of the feeding roller 5 and the sheet. Since the frictional force necessary for conveyance is generated between the lowermost sheet and the lowermost sheet, the curling of the sheet is corrected, and the lowermost sheet is subjected to the weight of a weight W placed in order to oppose the gap 1a as accurately as possible. Because it moves in the state,
The feeding force of the feeding roller 5 must be strong enough to withstand these forces, but as shown in FIG.
If the rear end of the sheet is in the cassette and is under the weight of the sheet and weight even when it is gripped by the pair of conveyor rollers 10 and the traction action is started, the rear end of the sheet is held by the pair of conveyor rollers 10. This will place a heavy burden on you. Of course, the distance between the leading edge of the cassette and the pair of conveying rollers 10, indicated by the symbol l in the figure, is set large, and the swinging stroke of the feeding roller 5 is also set to a dog position, so that the sheet position at the time when the pair of conveying rollers grips the sheet P is increased. One possibility is to have the sheet end ejected outside the cassette, but in order to do this, it is necessary to create a structure that allows the cassette feeding device to completely feed the sheet out of the cassette. This would be impossible due to the structure of the transport mechanism.

The present invention has been made in view of such a situation, and includes the lever 4. A member that operates as the feeding roller 5 swings acts on the sheet bundle, and during the traveling stroke of the feeding roller, when a sheet that has already been discharged outside the cassette is gripped by a pair of conveying rollers outside the cassette, A pair of conveying rollers that has only a small conveying force capable of conveying one sheet, such that the member receives all the weight of the sheets, weights, etc. in the cassette so that this weight is not applied to the moving sheet. However, the present invention provides a feeding device that can sufficiently feed sheets to the next process site, and can reduce the space by bringing a pair of conveying rollers closer to the cassette. .

Embodiments of the present invention will be described below with reference to the accompanying drawings, particularly FIGS. 2 and 3.

The cassette mounting table 3 disposed inside the image forming apparatus, etc., has a cassette P and a weight W which are stored in an overlapping manner, as in the case shown in the first figure. A feeding mechanism similar to the one described above (although not limited to this) is provided on the side, and the sheets are sequentially fed from the bottom of the stack to the bottom of the front plate 1. Gap 1
It is assumed that the structure is such that it is discharged from a.

In Figures 2 and 3, levers are shown for simplicity.

The description of members corresponding to the feeding rollers and the like is omitted, and only the direction of the reciprocating shaft 6 and the elongated hole 3a through which it moves is shown by chain lines.

FIG. 2 shows the shaft 6 at its right end position in the figure so that a feed roller (not shown) can feed sheets.

In such a device, in the present invention, a pin 14 is attached to a suitable position on the base 3, and a lever 12 is arranged on this so as to extend substantially in the moving direction of the shaft 6, and an arm 12a is attached to the free end of the pin 14. is the installation. A spring 13 is attached to the lever 12.
is suspended so that the lever 12 always has the habit of rotating in the direction of arrow B, so that the lever 12 is attached to the shaft 6.
is in pressure contact with.

A notch 12d is formed in the lever 12, and the shaft 6 is fitted into the notch 12d. At this time, the tip 12b of the arm 12a protrudes from the elongated hole 2 of the cassette toward the sheet side to hold the sheet. As shown in the figure, it is slightly offset from the bottom of the cassette.

The position of the arm tip 12b is determined by the action of the spring 13.

There is also a relationship such as the position of the pair of transport rollers outside the cassette,
It is preferable to position it behind the rear edge of the Narutake sheet and close to the rear edge.

i Lever 4 shown in the first figure. Spring 8. When an operating mechanism (not shown) such as a solenoid 9 is actuated to move the shaft 6 to the left from the position shown in the second figure, the shaft 6 moves into the notch 1.
2d and run along the upper edge 12c of the lever 12 while pressing the lever. At this time, the tip 12b of the arm 12a attached to the lever 12 escapes downward from the elongated hole 2 as the lever rotates and assumes the position shown in FIG. Feed roller (
(not shown) frictionally engages with the sheet, discharges it through the gap (a) of the cassette, and further advances to be gripped and conveyed by a pair of conveying rollers 10.

If the tip of the arm P1 is gripped by a pair of conveying rollers and is actively pulled by the pair, the shaft 6 moves back and fits into the notch 12d of the lever 12. The state shown in the second figure is again reached, and the tip 12b of the arm 12a raises the sheet bundle P and the weight W, so that the rear portion of the discharged sheet P1 that is still in the cassette is not subjected to any load due to the sheet or weight. Therefore, the pair of conveying rollers can reliably feed the sheet P1 to the next process with a relatively weak traction force.

4 and 4A show another embodiment of the present invention, in which the front plate 1 is set to have a gap through which only one sheet of the cassette C can pass. , are arranged so as to be slidable upward in a pair of grooves ib (only one of which is shown in the figure) formed in the cassette side plate, and both side edges of the front plate are not related to the sheet passage gap. 1c is extended downward, and on the other hand, the free end of the lever 12 is extended in that direction to form a receiving part 12e at a position facing the side edge 1c of the front plate, so that the shaft 6 of the lever 12 When the lever is inserted into the notch and the free end of the lever is raised, the front plate 1 as well as the sheet bundle, weight, etc.
It is configured to be able to rise due to contact friction with the arm.

With this configuration, the sheet P1 has a gap of 1
When the sheet is ejected from the gap 1a, the gap 1a becomes large, so even if the sheet is curled or wavy, it will not get caught on the edge of the gap 1a and will not be able to move between the conveying rollers. The load applied to 1o can be reduced. This can be applied not only to the front plate l, but also to other parts that come into frictional contact with the front plate as the sheet advances and is ejected.

In the embodiment described above, the lever 12 has a notch 1.
2d is allowed to raise the seat, but it is also possible to change the timing or duration of the operation using an appropriate link mechanism.

Further, in the above embodiments, the movement of the shaft 6 and the cooperative operation of the lever 12 are performed mechanically, but it is of course possible to use electrical means such as using a plunger or the like to operate the lever.

As explained above, the present invention is capable of locking the sheet bundle stacked and stored from the bottom to the feeding means.
In a device that discharges sheets one by one, when the discharged sheet is gripped and conveyed by a pair of conveyance rollers on the conveyance path, all sheet bundles, weights, etc. other than the gripped sheet are removed from the gripped sheet. Since the structure is configured to separate the sheets and eliminate the increase in load on the pair of conveyance rollers due to the weight of sheet bundles, etc., it is possible to use a small conveyance roller with a weak conveyance force, and the conveyance roller can also be used as a cassette for storing sheets. Since the sheets can be placed close to each other, the space for transporting the sheets can be made smaller, and the distance the sheets must be moved until the sheets in the cassette are gripped by the transport rollers can also be reduced, so it is possible to reduce the amount of reciprocating and shaking needed to eject the sheets. This has a significant effect, such as being able to reduce the stroke of the moving mechanism.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing the configuration of a sheet feeding device that sequentially takes out sheets starting from the lowest sheet; FIGS. 2 and 3 are explanatory diagrams showing an embodiment of the present invention and showing its operating mode; FIG. 4 and FIG. 4A are a side view and a perspective view of essential parts showing another embodiment of the present invention. 1... Front plate, 1a... Gap, 2, 3a... Long hole, 3...
...Base part, 4...Lever, 5...Feeding roller, 6...
- Shaft, 7 - One-way clutch, 8 - Spring, 9 - Solenoid, 10 - Conveyance roller pair, 12 - Lever, 13 - Spring. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A large number of sheets to be processed are stacked and stored in a container, and the sheet is sequentially taken out from the bottom, and discharged from the container, and the leading edge of the discharged sheet is applied to a conveying roller. A feeding device in which a discharged sheet is gripped by a conveyance roller, and a means is provided for separating all sheets above the discharged sheet from the discharged sheet.