JPS62255323A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To supply sheets in a condition in that a cassette is mounted, by a method wherein a lifter lowering control means is shifted to a lowering control position or a lowering control release position in linkage with action of supplying sheets to a cassette. CONSTITUTION:When a duplicator detects the absence of a sheet with the aid of a detecting means and is stopped, a sheet S supplied by an operator is prepared, a cassette cover 25 is rotated around a rotary center 25b for opening. A press plate 25d, formed integrally with the cassette cover 25, is gradually risen along with a hinge part moved upward in linkage with rotation of the cassette cover 25, the press plate is brought into contact with a projectionform engaging part 21b of a latchet lever 21, and pushes upward the projectionform engaging part 21b. In which case, the latchet lever 21 is switched, a lifter 12 is released from lowering control, and the lifter 25 is lowered under gravity. This lowering also causes lowering of a middle plate 10 of a cassette C to separate the middle 10 from a sheet feed roller 7 to supply the sheet S in the cassette C by an operator.

Description

[Detailed Description of the Invention] (a) Industrial Application The present invention relates to a sheet feeding device of an image forming apparatus such as a copying machine or a laser beam printer, and more particularly, to a box-shaped sheet feeding device that stores a large number of sheets. Cassette ii! [! The present invention relates to a sheet feeding device of a type (cassette type) that is attached to a forming apparatus main body and feeds sheets stored in a cassette.

(B) Conventional technology Conventionally, a cassette-type sheet feeding device in an image forming apparatus such as a copying machine is equipped with a removable cassette that stores a large number of sheets in a cassette mounting section, and a sheet feeder is installed near the cassette mounting section. A lifter installed in the cassette lifts the sheets stored in the cassette together with the intermediate plate on which the sheets are stacked, and presses the sheet against a sheet feeding means such as a paper feeding roller, and then rotates the sheet feeding means. It is designed to be delivered.

Then, when the cassette runs out of sheets, the cassette
To replenish sheets, the cassette is pulled out from the cassette mounting section, placed on the top surface of the image forming apparatus, and then refilled with sheets. Note that when the cassette is pulled out from the cassette mounting section, the lifter no longer supports the cassette, and the middle plate descends to the bottom of the cassette, making it possible to supply and stack sheets on the middle plate. Then, when the cassette is replenished with sheets, it is mounted in the cassette mounting section again.

→ Problems to be solved by the invention In recent years, image forming apparatuses, especially copying machines, have been equipped with various applications such as a digitizer (area indicating device) and RDF (ring type automatic sheet feeding device) on the top of the main body. Systematization and high functionality is progressing, with cages and cages being added. Therefore, there may not be a place on the top of the copying machine to place the pulled out cassette as in the past, and a desk or floor is required to temporarily place the cassette when replenishing sheets, which reduces work efficiency. Getting worse. Also, if you hold the cassette in one hand without placing it on a desk or the like and replenish sheets into the cassette with the other hand, the sheets may not fit properly in the cassette and may fold, resulting in wasted sheets or There is a possibility that it may cause transportation failure.

Furthermore, since the sheet feeding device is adapted to supply sheets to the cassette pulled out from the cassette mounting section, if the cassette is still mounted in the cassette mounting section, the middle plate of the cassette will be lifted by the lipter, Since it is pressed against the sheet feeding means, sheets cannot be stacked on the intermediate plate and sheets cannot be replenished.

Means for Solving the Problems The present invention aims to solve the above-mentioned problems, and it is an object of the present invention to move the lifter lowering restricting means to the lowering restricting position or to the lowering restricting position in conjunction with the sheet replenishment operation of the cassette. The present invention is characterized in that a switching means is provided for switching to a lowering restriction release position.

(E) Operation Based on the above-mentioned configuration, the lifter whose descent is regulated by the lifter lowering*flilJ means lifts the middle plate built in the cassette toward the sheet feeding means constituting the sheet feeding device, and The sheets stacked on the intermediate plate are held at a position where they are pressed against the sheet feeding means. Then, when the sheets are fed by the sheet feeding means and run out, a sheet replenishing operation such as opening a cassette lid is performed to replenish the sheets. Then, in conjunction with the sheet replenishment operation, the switching means switches the lowering restriction means to the lowering restriction release position, and the lifter, whose descent has been restricted by the lifter lowering restricting means, descends, and furthermore, the lifter moves to a predetermined position. The middle plate held in the lifted position loses the support of the lifter and descends to the bottom of the cassette, opening a space between the middle plate and the sheet feeding means. Then, sheets are stacked on the intermediate plate that has descended to the bottom of the cassette, and sheets are replenished while the cassette remains attached to the cassette mounting section. Then, when the sheet replenishment is completed, the switching means switches the lifter lowering restriction means to the lowering restriction position in conjunction with the sheet replenishing operation such as closing the cassette lid.

Therefore, the lifter lifts the middle plate on which the sheets are loaded,
Pressing the sheet against sheet feeding means.

(f) Example Embodiments of the present invention will be described below along with the drawings.

As shown in FIG. 1, the sheet feeding device W1 has a cassette loading section 6 facing the cassette loading/unloading port 2 of the copying machine main body M and consisting of an upper guide 3, a lower guide 5, etc. 9; A paper feed roller 7 and a pair of separation rollers 9 are provided above the cassette mounting section 6, and a cassette C storing a large number of sheets S is guided by these guides 3 and 5 and mounted on the cassette mounting section 6. At the same time, the sheets S stored in the cassette C are separated and fed one by one by a paper feed roller 7 and a pair of separation rollers 9. Further, the cassette C has an opening CI formed from the front surface to the bottom surface, and a fitting groove C2 provided at the lower edge portion of the lower guide 5 to fit into the positioning protrusion 5m. A middle plate 10 on which sheets S are loaded is built-in. Then, the intermediate plate 10 is moved toward the paper feeder 7. Further, below the separation roller pair 9, a lifter support shaft 1) is rotatably supported by a side plate of a copying machine main body M (not shown), and a lifter 12 is fixed to the support shaft 1). The lifter 12 is inserted into the cassette mounting part 6 through the lifter opening 5b of the lower guide, and moves up and down according to the rotation of the support shaft 1), and when moving upward, it touches the middle plate 10. lift. Further, as shown in FIG. 2, a fan-shaped lifter moving plate 13 having a tip gear 13a at its tip is fixed to the lifter support shaft 1). It moves vertically together with the lifter 12 via the support shaft 1). In addition, the lifter moving plate 13
Facing f4#J wheel 13a and ratcheting)・Gear shaft 15
is fixed to a copper plate (not shown) of the copying machine main body M, and a ratchet gear 16 is attached to the ratchet tII'nL shaft 15.
and an electromagnetic clutch 17 are each rotatably supported. And that ratchet! - The gear 16 is provided with a clutch fitting part 16sL, and the fitting part 16a fits into the inner cylinder 17a of the electromagnetic clutch 17, thereby integrally connecting the ratchet gear 16 and the magnetic latch 17. Connect to. Further, the clutch 17 is provided with a drive gear 19, and the clutch 17 is connected to a gear 20 that fits into the drive gear 19.
The power obtained from a power source (not shown) is controlled through the inner cylinder 17a to rotate or stop the ratchet gear 16 that is integrally engaged with the inner cylinder 17a. Furthermore, a ratchet tooth 16b is provided on the enlarged diameter portion of the ratchet tooth Jf1)6.
However, a small diameter gear 16c (indicated by the line W4) is formed in each small diameter part, and the small diameter gear 16c is located at the tip of the lifter moving plate 13 gI4tI! It meshes with the first wheel 13a.

A ratchet lever 21 is swingably supported on a support shaft 22 facing the ratchet teeth 16b of the ratchet gear 16, and a claw portion 21a is formed at one end of the lever 21. is the ratchet tooth 16 above.
b. Furthermore, a protruding engagement part zib is formed on the ratchet lever 21 ((jl fJJ) and protrudes from the cassette mounting part 6 so as to be able to engage with the upper surface C3 of the side wall of the cassette C, and the protrusion A spring 23 is stretched around the engaging portion 21b, and the ratchet lever 21 is held in its claw portion 21a by the spring 23.
is biased to engage the ratchet teeth 16b of the ratchet gear 16, and the protruding engagement portion 21b
When it is suppressed and moved upward against the tension of 3, it is displaced,
The pawl portion 21m is moved away from the ratchet teeth 16b and switched to a position where the engagement is released.

On the other hand, the cassette C is provided with a cassette lid 25, and the cassette fi25 has a rib 25a on its negative end.
is formed, and a convex rotation center 25b is formed on the rib 25m.
The rotation center 25b is engaged with the lid support portion C4 of the cassette C and supported so as to be openable and closable. Furthermore, near the rotation center 25b of the cassette lid 25, as shown in FIG. When the cassette lid 25 is closed, the pressing plate 25d is provided on the upper surface C3 of the side wall of the cassette C. , (see FIG. 4), and does not protrude from the upper surface C3 of the side wall, and the cassette lid 25
When opened, as the hinge portion 25c moves upward, it is displaced so as to stand up.

Since the present embodiment has the above-described configuration, the cassette C is first inserted through the attachment/detachment opening 2, guided by the upper guide 3 and the lower guide 5, and installed at a predetermined position in the cassette attachment section 6. At this time, the cassette C is positioned with its fitting groove 02 fitting into the positioning protrusion 5a of the lower guide 5. Furthermore, when the cassette C is inserted into the attachment/detachment port 2, the side wall upper surface C3 of the cassette C comes into contact with the protruding engagement part 21b of the ratchet lever 21, pushing the engagement part 21b upward. Then, the ratchet lever 21 releases the spring 2.
3, and the claw portion 21a is switched to move away from the ratchet m16b of the ratchet gear 16, thereby releasing the rotation restriction of the ratchet gear 16 in the direction of arrow B (see FIG. 2). . Therefore, the lifter moving plate 13, which had been restricted from moving downward by meshing the tip gear 13a with the small diameter gear 16c of the ratchet tooth J1[16, is no longer restricted from moving downward, and the lifter moving plate 13 The lifter 12, which integrally moves up and down, is released from the lowering restriction and lowered by its own weight to the lowest position. Therefore, the tip end 12a of the lifter 12 does not collide with the inserted cassette C. Then, when the cassette C is positioned, the upper surface C1 of the side wall of the cassette is no longer pushed up against the protruding engagement portion 21b of the ratchet lever, and the ratchet lever 21 uses the spring 23 to ratchet the claw portion 21a. tI1) Return to the position where it engages with 6b. Then, the ratchet gear 16 is again restricted from rotating in the direction of arrow B by the ratchet lever 21, and the lifter 12, which is connected to the ratchet gear 16 via the lifter moving plate 13 and the lifter support shaft 1), is restricted only from descending. It waits below the intermediate plate 10 of the positioned cassette +-C.

When a copy button (not shown) is pressed to start a copy (image forming) operation (copy-related operation), the electromagnetic clutch 17 is activated and the rotation of the drive gear 19 in the direction of the arrow (see Fig. 2) is activated. It is transmitted to the tooth $16 and also to the tip gear 13m of the footer moving plate 13 via the small diameter gear 16c. Then, the tip gear 13m
is moved upward and rises integrally with the lifter moving plate 13.
The tip 12m of the descending lifter 12 rises, the middle plate 10 of the cassette C is lifted upward by the lifter 12, and the sheets S loaded on the middle plate 10 are transferred to the paper feed roller 7.
rise towards. When the upper surface of the sheet S reaches a predetermined position, a detection means (not shown) detects the sheet S.
is detected, the operation of the electromagnetic clutch 17 is stopped, the lifting of the lifter 12 is stopped, and the lifter 12, which is restricted from falling, is held at that position. Then, the paper feed roller 7 rotates to feed the sheet S.

Furthermore, when the cassette C is pulled out from the cassette mounting part 6, the upper surface C3 of the side wall of the cassette C is connected to the protruding engagement part 21 of the ratchet lever 21, as in the case of inserting the cassette C described above.
b, and pushes up the engaging portion 21b to release the restriction on the lifter 12 from descending. Then, the lifter 12 descends under its own weight and stops at the lowest position.

Furthermore, if the cassette is still attached to the cassette attachment part 6,
The operation when replenishing sheet S to C will be explained.

When the sheets stored in the cassette C run out, the photocopying machine detects the absence of sheets by the detection means and stops. Here, the operator prepares the sheet S to be supplied, and the cassette M2
5 around the rotation center 25b to open it. At this time, the suppression plate 25d integrally formed with the cassette lid 25 gradually rises according to the hinge portion 25C that moves upward in conjunction with the rotation of the cassette lid 25, and the ratchet lever 21
The projection-like engagement portion 21b is contacted with the projection-like engagement portion 21b.
push upward. Then, in the same way as described above, the ratchet lever 21 is switched, the lowering restriction of the lifter 12 is released, and the lifter 12 is lowered by its own weight, and as a result, the middle plate 10 of the cassette C is also lowered, and the middle plate 10 and the paper roller 7
The space between the cassette C and the cassette C is opened so that the first author can replenish the cassette C with sheets S (see FIG. 3). In addition, the cassette lid 25 can be rotated until the center of gravity when opened is closer to the front opening C1 of the cassettes 1 and C than the center of rotation 25d, so the cassette lid 25 rotated to this position cannot be moved under its own weight. Never closes. Furthermore, the spring 23 that biases the ratchet L/bar 21 is normally tensioned with a spring force of around 100 g, and although the protruding engagement portion 21b of the ratchet lever 21 presses the pressing plate 25d, the cassette lid 25 is It does not prevent it from being held in the open position. When the cassette fi25 is closed after replenishing the sheets S, the suppressing plate 25d moves downward as the hinge part 250 moves downward in conjunction with the rotation of the lid 25, and the protruding shape of the ratchet lever is caused by the pressing plate 25d. There is no longer any pushing up towards the engaging portion 21b, and the lifter 12 is in a state where its descent is restricted. Then, when the copy button is pressed, the middle plate 10 rises, and the sheets S stored in the cassette C are separated and fed one by one by the paper feed roller 7 and separation roller pair 9, and the copying operation is started. will continue.

In the above-mentioned embodiment, the ratchet lever 21 is switched by the suppression plate 25d that is linked to the opening/closing operation of the cassette lid 25 to release the restriction on the lowering of the lifter 12. However, the present invention is not limited to this. When replenishing, lift the rear end of the cassette C and place it on the top surface C3 of the side wall of the cassette C.
ratchet on a part of the lever 21) and the protruding retaining portion 21 of the lever 21
b may be pushed up to switch the ratchet lever 21 to release the restriction on the lifter 12 from descending.

Furthermore, the present invention is applicable to sheet feeding apparatuses that are equipped with a separate drive source for driving a lifter and that electrically controls the drive source, as long as part of the drive source can be mechanically released. can.

(G) As described in detail, according to the present invention, it is possible to replenish sheets with the cassette attached to the cassette mounting section, so when replenishing sheets, the cassette can be removed and placed in another location. This saves you the trouble of placing it in the Further, since sheets can be replenished stably into the cassette mounted in the sheet loading section, there is no need to miss inserting sheets, and there is no need to waste sheets due to misinsertion or defective sheet conveyance.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a sheet feeding device according to an embodiment of the present invention, No. 2ryJ is a perspective view showing a ratchet lever that is a lifter lowering regulating member, and Fig. 3 is a suppressing plate that operates to open the cassette lid. Fig. 4 is a perspective view showing the state in which the ratchet lever is switched to the lifter downward restriction release position in conjunction with the closing operation of the cassette lid. Indicates the status @′
l? g, Fig. C...Cassette, 1...Sheet feeding device,
6...Cassette mounting part, 12...Lifter, 2
1... Lifter descends! 1t JJ means (ratchet lever), 25... cassette lid, 25d switching means (suppressing plate).

Claims (2)

[Claims] (1) A sheet feeding device that includes a cassette that stores a large number of sheets, a lifter that lifts the sheets stored in the cassette toward a sheet feeding device, and a lifter descent restriction device that restricts the descent of the lifter. The sheet feeding device according to the present invention, wherein the cassette is provided with a switching means for switching the lifter lowering restriction means to a lowering restriction position or a lowering restriction release position in conjunction with sheet replenishment operation of the cassette. (2) The switching means is a member that is displaced in conjunction with opening and closing of the cassette lid, and when the cassette lid is opened, the lifter descent restriction means is switched to a descent restriction release position, and when the cassette lid is closed, the lifter descent restriction is restricted. A sheet feeding device according to claim 1, wherein the means is switched to a lowering restriction position.