JPH054299B2 - - Google Patents

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. In the cassette C, sheets P to be processed are stored in a stacked manner. The cassette C is placed on a stand 3 in the image forming apparatus, and a long hole 2 extending in the sheet running direction is formed in the bottom surface of the cassette C.

A long hole 3a is formed in the side wall of the platform 3, into which a shaft 6 on which a feed roller 5 to which a one-way clutch 7 is attached is mounted is loosely fitted so that it can only slide. 1, and the one-way clutch 7 is mounted so as to rotate the feed roller 5 only in the direction of arrow A in FIG.

The shaft 6 is also loosely fitted into an elongated hole 4a formed at the free end side of an arm 4 which is pivotally connected to a pin 4b formed at a suitable position in the image forming apparatus. 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.

If solenoid 9 is deenergized, arm 4
Therefore, the roller 5 etc. that are pivotally attached to this are shown by chain lines in the diagram.
It is maintained at the CE position by the action of spring 8,
The feeding roller 5 is in close contact with the surface of the lowermost sheet in the cassette through 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. Since a gap 1a is formed at the lower end of the front edge of the cassette C in the paper traveling direction through which only one sheet can pass, only the bottommost sheet traveling to the left is ejected from the cassette. It is assumed that the material reaches a pair of transport rollers 10 via a transport path 11, is actively gripped by the pair, and is further transported to the next process position.

When the solenoid 9 is deenergized after a predetermined time, the lever 4, feed roller 5, etc. return to the position indicated by the chain line CE in FIG. 1 by the action of the spring 8, but at this time the clutch 7 is released and Since the feed roller 5 rotates freely, the roller does not affect the sheet newly brought to the bottom surface.

By the way, in the case of a feeding device having such a configuration,
Since the sheet stack is discharged from the bottom, the moving sheet generates the weight of all the sheets above it, as well as the frictional force required for conveyance between the feeding rollers 5 and the sheet. , the feed roller 5 moves under the weight of the weight W placed to correct the curl of the sheet and to make the bottom sheet face the gap 1a as accurately as possible. The feeding force must be able to withstand these forces. Furthermore, as shown in FIG. 1, even when the leading edge of the sheet _P1 to be moved and discharged comes out of the cassette and is gripped by a pair of conveyance rollers provided in the conveyance path 11 and the traction action is started, the sheet P1 remains behind. If the end is in the cassette and is subject to the weight of sheets and weights, a large load will be applied to the pair of conveying rollers 10. Of course, the distance between the front edge of the cassette shown by the symbol l in the same figure and the pair of conveying rollers 10 is increased, and the swinging stroke of the feeding roller 5 is also increased so that the trailing edge of the sheet at the time when the pair of conveying rollers grips the sheet _P1 is increased. It is conceivable to eject the sheets out of the cassette, but this requires a structure that allows the cassette feeding device to completely feed the sheets out of the cassette. This is not possible with a cassette due to the structure of the transport mechanism.

The present invention has been made in view of this situation, and involves storing a large number of sheets to be processed in a container in a stacked manner, and sequentially feeding out the sheets starting from the bottom of the stored sheets, and transferring the fed sheets to the container. In the feeding device, the sheet is conveyed by a conveying means provided on the outside of the sheet, and the feeding means feeds out the sheet by frictionally engaging the lowermost sheet and reciprocating in the sheet feeding direction. a lifting means biased in a direction capable of lifting the stored sheets; and a control means provided on the feeding means and controlling the operation of the lifting means in conjunction with the reciprocation of the feeding means. The control means controls the lifting operation of the lifting means against the biasing force until the sheet is sent out by the feeding means and is gripped by the conveying means, and After the sheet is gripped by the conveying means, the restriction is released and the lifting means lifts the stored sheet from the rear side of the sheet to be fed out, and the stored sheet is completely removed from the sheet being fed out. It is characterized by being spaced apart.

According to this configuration, after the sheet to be sent out is gripped by the conveyance means, the lifting means lifts the sheet stored in the container and completely separates it from the sheet to be sent out. The weight of the sheets being fed is not added, and a large load is not applied to the conveying means via the sheets sent out.

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

The cassette mounting stand 3 disposed inside the image forming apparatus, etc., has sheets P and weights W which are stacked and stored inside, as in the case shown in the first figure. is equipped with a feeding mechanism similar to the one described above (though not limited to this, of course), and feeds sheets sequentially from the bottom of the sheet bundle to the gap formed at the bottom end of the front plate 1. It is assumed that the structure is such that it is discharged from 1a.

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 in its right-hand end position and the feed rollers (not shown) ready to feed sheets.

In such things, in the present invention,
Attach the pin 14 to the appropriate position on the base 3, and attach the lever 1 to this.
2 is arranged so as to extend substantially in the direction of movement of the shaft 6, and an arm 12a is attached to its free end. A spring 13 is attached to the lever 12 which is a lifting means.
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 in pressure contact with the shaft 6 which also serves as a control means.
A notch 12d is formed in the lever 12, and the shaft 6 is fitted into this 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 and biases the sheet so as to be slightly separated from the bottom surface of the cassette as shown. Although the position of the arm tip 12b is related to the action of the spring 13 and the position of the conveying roller 10, which is a conveying means outside the cassette, it is likely that it is located behind and close to the rear edge of the Narutake sheet. It is preferable to

Lever 4, spring 8, solenoid 9 shown in the first figure
Activate an operation mechanism (not shown) such as
When the shaft 6 is moved leftward from the position shown in the second figure, the shaft 6 escapes from the notch 12d and runs 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 long hole 2 as the lever rotates and assumes the position shown in FIG. 3, so that it is attached to the shaft 6. A feeding roller (see FIG. 1) 5 serving as feeding means frictionally engages with the sheet and discharges the sheet from the gap 1a of the cassette.

The leading edge of sheet P ₁ is held by a pair of conveying rollers,
As a result, the shaft 6 moves back to fit into the notch 12d of the lever 12, and the lever 12 returns to the state shown in the second figure, and the arm 12a tip 12
Since b raises the sheet bundle P and weight W,
Since the rear portion of the discharged sheet P ₁ still in the cassette is no longer loaded by the sheet or weight, the conveying roller pair reliably feeds the sheet P ₁ to the next process with a relatively weak traction force. be able to.

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 able to slide upwardly in a pair of grooves 1b (only one of which is shown in the figure) formed in the cassette side plates, and both side edges of the front plate are not related to the sheet passage gap. 1c is extended downward, and the free end of the lever 12 is extended in that direction so that the side edge 1c of the front plate is extended downward.
A receiving portion 12e is formed at a position facing the
When the shaft 6 is fitted into the notch of the lever 12 and the free end of the lever is raised, the front plate 1 is also raised together with the sheet bundle, weight, etc. due to contact friction with the sheets. It has been done.

By configuring in this way, sheet P ₁
When the sheet is discharged from the gap 1, the gap 1a becomes large, so the sheet is curled,
Even if it is curved in a wavy manner, it will not get caught on the edge of the gap 1a, and the load on the pair of conveying rollers 10 can be reduced. This means that
It can be applied not only to the front plate 1 but also to other parts that come into frictional contact with the front plate 1 as the sheet is advanced and discharged.

In the embodiment described above, the notch 12d is provided in the lever 12 to raise the seat, but it is also possible to change the timing or duration of the actuation using an appropriate link mechanism. .

Furthermore, in the above embodiment, the movement of the shaft 6 and the lever 1
Although the cooperative operation of the second embodiment is performed mechanically, it is of course also possible to use electrical means such as operating a lever using a plunger or the like.

As explained above, the present invention is configured to discharge sheets one by one from the bottom of stacked stacked sheet bundles by locking this with a feeding means, in which the sheets to be sent out are After being gripped by the container, the sheet stored in the container is moved upward and completely separated from the sheet to be fed out, so that the weight of the stored sheet is not added to the sheet to be fed out. Therefore, it is possible to use a small conveying means with a small conveying force without applying a large load to the conveying means through the sheets being sent out, which reduces costs. The device can be placed close to the device, making it possible to downsize the entire device.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing the configuration of a feeding device that sequentially takes out sheets starting from the lowest sheet;
3 and 3 show an embodiment of the present invention, and FIGS. 4 and 4A are side views and perspective views of essential parts, respectively, showing other embodiments of the present invention. 1...Front plate, 1a...Gap, 2, 3a...Long hole, 3...Base, 4...Lever, 5...Feeding roller (feeding means), 6... Axis (controlling means) , 7... One-way clutch, 8... Spring, 9... Solenoid, 1
0... Conveyance roller pair, 12... Lever (lifting means), 13... Spring.

Claims (1)

[Claims] 1. A large number of sheets to be processed are stacked and stored in a container,
In a feeding device that sequentially feeds out the stored sheets starting from the lowest sheet and conveys the sheets to be fed out by a conveying means provided outside the container, the sheet is frictionally engaged with the lowest sheet. a feeding device that sends out the sheet by reciprocating in a sheet feeding direction; a lifting device that is biased in a direction capable of lifting stored sheets; and a control means for controlling the operation of the lifting means in conjunction with the reciprocating movement of the feeding means, and the control means controls the operation of the lifting means until the sheet is sent out by the feeding means and gripped by the conveying means.
The lifting operation of the lifting means is restricted against the urging force, and after the sheet sent out is gripped by the conveying means, the restriction is released and the sheet sent out is stored from behind by the lifting means. A feeding device that lifts a stored sheet and completely separates the stored sheet from the sheet to be fed out.