JPH01209231A - Sheet feeder - Google Patents

Abstract

PURPOSE:To contrive the easiness of mounting and removing a cassette and the prevention of a paper feed roller or the like from its deformation and damage by arranging a lifter in a lowering position not interfering with mounting the cassette, when it is mounted, while only releasing the lifter from its lowering restriction, when the cassette is removed, further enabling a rising speed to be easily controlled. CONSTITUTION:When a cassette C is inserted into a mount-removal port 3, a left side pin 30 slides on peripheral sides 35a-35c of a guide 35, when the cassette C is positioned, the pin 30 stops by the peripheral side 35c. Next, when a copy button is pressed, a sheet feed signal is output from a control part, and actuating an electromagnetic clutch 22, a drive gear 23 transmits its rotation in a direction of arrow head A to a sector gear 33a. Then moving the gear 33a to the upper and a point end part 6a of a lifter 6 to the upper, a sheet of the cassette C is lifted by the lifter 6. The sheet, when it places its upper surface to run on a predetermined position, is detected, and the clutch 22 stops, stopping the lifter 6 in that position. The lifter is restricted in its lowering holding its position, and a paper feed roller rotates feeding the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a sheet feeding device in an image forming apparatus such as a copying machine or a laser beam printer. A method in which the cassette is attached to the main body of the image forming apparatus and the sheets stored in the cassette are fed (
cassette type) sheet feeding device.

([1) Prior Art Conventionally, some copying machines are equipped with a cassette-type sheet feeding device.

As shown in FIG. 3, the sheet feeding device 1' has a box-shaped cassette C' that stores a large number of sheets, and faces the cassette loading/unloading port 3 of the copying machine M, and is mounted on the side plate of the copying machine main body. A lifter support shaft 5 is rotatably supported. A lifter is disposed on the lifter support shaft 5 with one end fixed to the lifter support shaft 5, and further, arms 7.7 are arranged on both sides of the shaft 5 with one end fixed respectively.
The tip 6a of the lifter 6 and the tips 7a, 7a of the arm 7.7 can move up and down together, and are attached upward by tension springs 9, 9 provided on the arm 7.7. Forced. Furthermore, these arms 7.
Slide pins 10, 10 are implanted in the tip portions 7a, 7a of the cassette C.
When sliding along the sides 11a, llc and lower side 11b of the inverted trapezoidal guides 11, 11 provided on both side plates of the arm 7.7, the tips 7a, 7a of the arms 7.7 and the tip of the lifter 6 6a are adapted to move up and down according to the movement of the pins 10 and 10, respectively.

Then, in the feeding device 1', when the cassette C' is installed in the cassette attachment/detachment port 3, the slide pin 10.10 is inserted into the side sides 11a, lla and the lower side 11 of the inverted trapezoidal guide 11.11.
When the cassette C' is slid along the sides 11c and 11b and reaches the sides 11c and 11c, the cassette C' is positioned. At this time, the tip 6a of the lifter 6 initially descends according to the movement of the pins 10, 10, enters below the cassette C' in the descending state, then rises as the pin rises, and then Once C' is positioned, based on the sub link 9,
The sheets stored in the cassette C' are urged toward a paper feed roller (not shown).

Also, when removing the cassette C', the pins 10 and 10
slides around the guides 11, 11 in the reverse order of installation to lower the tip 6a of the lifter 6, and then when the cassette C' is removed, the tip 6a of the lifter 6 moves upward. is moved and held.

(c) Problems to be Solved by the Invention By the way, in the sheet feeding device 1' described above, the cassette C'
When attaching and detaching the cassette C', the cassette C' is attached and detached against the tension of the tension spring 9.9, which has the drawback that the operation feels heavy. Furthermore, the tip 6a of the lifter 6 or the tension spring 9
, 9, the cassette C'
When the lifter 6 is installed, the tip 6a of the lifter 6 rises rapidly and comes into contact with the sheet stored in the cassette C', and the impact causes deformation of the paper feed roller (not shown) provided above the sheet. Or there is a defect that may cause damage.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet feeding device that does not cause the lifter to rise suddenly when loading a cassette and is easy to operate.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned circumstances. For example, as shown with reference to FIGS. 1 and 2, facing the cassette loading/unloading port (3), a lifter (6) that urges the sheets stored in the cassette (C) upward; a lifter moving drive means (20) that moves the lifter (6) upward in response to a sheet feeding signal; 6), and lifter descent restriction release members (29) and (30) that release the restriction of the lifter descent restriction means (31) when the cassette (C) is removed.
A sheet feeding device (1) comprising:

(e) Operation Based on the above configuration, the cassette (C) or the cassette attachment/detachment opening (
3) is installed and the sheet feed signal is output,
The lifter (6) is moved to a position that urges the sheet upward and is restricted from descending.

When the cassette (C) is removed from the cassette attachment/detachment port (3), the lifter (6) is released from the downward restriction and descends without interfering with the attachment/detachment of the cassette (C).

Note that the symbols in parentheses above are shown for reference and do not limit the configuration in any way.

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

Note that the same parts as those of the conventional sheet feeding device 1' described above are given the same reference numerals, and a description thereof will be omitted.

As shown in FIGS. 1 and 2, the sheet feeding device 1 of this embodiment has a box-shaped cassette C like the conventional sheet feeding device 1' described above, and also has a cassette C that is attached to a cassette of a copying machine. It is provided with a lifter support shaft 5 facing the ejection port 3 and rotatably supported on the side plate of the copying machine main body, and a lifter support shaft 5 fixedly attached to the lifter support shaft 5.

A lifter moving mechanism 20 for moving the lifter 6 upward is arranged facing the lifter support shaft 5, and the lifter moving mechanism 2o has a ratchet gear shaft 21. 21 is rotatably supported by a side plate (not shown) of the main body M of the copying machine. In addition, the gear shaft 21
An electromagnetic clutch 22 is fixed to the clutch 2.
A drive gear 23 is disposed at the gear 23, and the clutch 22 controls power from a power source (not shown) through a gear 25 meshing with the gear 23, so as to rotate or stop the ratchet gear shaft 21. It has become.

Further, a ratchet gear 26 is fixed to the gear shaft 21 adjacent to the drive gear 23.
A ratchet tooth 26a is provided on the enlarged diameter portion, and a gear 26a is provided on the small diameter portion.
6b is formed respectively. Further, a link-shaped member 27 is rotatably provided on the ratchet gear shaft 21 near the ratchet gear 26, and the ring-shaped member 27
Pins are implanted on the side surfaces to protrude on both the left and right sides, and as the left pin 30 rotates and moves, the right pin 29
are designed to rotate and move as one. Further, a ratchet lever 31 is swingably supported on a support shaft 32 facing the ratchet teeth 26a of the ratchet gear 26, and a pawl 31a is formed at one end of the lever 31.
The pawl 31a is adapted to engage the ratchet teeth 26a, and the other end of the lever 31 extends below the right pin 29 to form an arm 31b.

Further, a protrusion 31c is provided on the boss portion on the opposite side of the arm 31b.
is provided, and a spring 32 is stretched around the protrusion 31c.
The pawl 31a is urged to engage with the ratchet tooth 26a of the ratchet gear 26, and the right pin 29 receives an external pressing force via the left pin 30, and the spring 32
When the arm 31b is pressed and moved downward against the tension of
The claw 31a is disengaged from the tooth portion 26a.

Note that the right pin 29 is normally pressed against the arm 3 with a force such as a spring (not shown) that does not disengage the wind 31a.
It is biased so as to come into contact with 1b.

On the other hand, a lifter moving plate 33 is disposed on the lifter support shaft 5 facing the gear 26b of the ratchet gear 26. One end of the plate 33 is fixed to the shaft 5, and the other end is shaped like a fan. A gear 33a is formed, and the sector gear 33'a engages with the gear 26b to move the tip 6a of the lifter 6 upward.

Further, a quadrilateral guide 35 having left and right sides inclined is provided on the right side plate of the cassette C (FIG. 2(a)).

(b)), the left-hand pin 30 can be slid in sequence on each outer periphery 35a, 35b, 35c, 35d of the guide 35.

Since the present embodiment has the above-described configuration, as shown in FIG.
, 35c. When the cassette C is positioned, the left pin 30 reaches the outer periphery 35c and remains stationary. Next, when a copy button (not shown) is pressed to start the copying operation, a sheet feeding signal is output from the control section, and the electromagnetic clutch 22 is actuated by this signal, causing the drive gear 23 to rotate in the direction of the arrow. 1) is transmitted to the ratchet gear 26, and is also transmitted to the sector gear 33a via the gear 26b. Then, the sector gear 33a of the lifter moving plate 33 is moved upward, and the lifter moving plate 33
The tip part 6a of the lifter, which is integrated with the lifter support shaft 5, is moved upward, and by the lifter 6,
The sheets stored in cassette C are lifted upward. Then, when it comes to the top surface of the sheet or a predetermined position,
The sheet is detected by a detection means (not shown),
The operation of the electromagnetic clutch 22 is stopped, and the lifter 6 is stopped from moving at that position.

At this time, the pawl 31a of the ratchet lever 31 is engaged with the ratchet tooth 26a, and the arrow B of the ratchet gear 26
Since the rotation in the direction is restricted, the downward movement of the lifter moving plate 33 is restricted, and the lifter integrated with the moving plate 33 is restricted from descending, and its position is maintained. Then, a paper feed roller (not shown) rotates to feed the sheet.

Next, when the cassette C is pulled out from the cassette attachment/detachment port 3 (see FIG. 2(a)), the left pin 30 is pressed downward along the outer periphery 35c of the guide 35 and reaches the outer periphery 35d. At that time, the right pin 2 moves together with the left pin 30.
9 obtains a pressing force from the guide 35 and presses and moves the arm 31b downward against the tension of the spring 32, and the claw 31a
from the ratchet teeth 26a. Then, the restriction on the lowering of the lifter 6 is released, the lifter 6 descends under its own weight, and stops at the lowest position. When the cassette C is completely pulled out, the left pin 30 is released from the downward pressure, and the right pin 2 moves together with the left pin 30.
9 loses its pressing force and is returned to its original position by the tension of the spring 32. In this way, the lifter 6
Move to the lowest position where there is no problem in attaching and detaching the

(G) As described in detail, according to the present invention, when the cassette is installed, the lifter is in a lowered position that does not hinder the cassette installation, and when the cassette is removed, the lifter lowering restriction means is restricted. The cassette can be attached and detached very easily.

Furthermore, since the lifter is raised via the drive means, the speed of its rise can be easily controlled, and deformation or damage to the paper feed roller etc. due to the rapid rise of the lifter can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a sheet feeding device according to an embodiment of the present invention, and FIG. 2 is a diagram showing its operation, in which (a) is a side view, and (b)
) is a plan view. Further, FIG. 3 is a perspective view of a conventional sheet feeding device. DESCRIPTION OF SYMBOLS 1... Sheet feeding device, 3... Cassette attachment/detachment opening, 6... Lifter, 20... Lifter movement drive means (lifter movement mechanism), 29.30... Lifter descent restriction release member (right side) pin, left side pin), 31...
・Lifter lowering regulating means (ratchet lever), C.
...cassette.

Claims (1)

[Claims] (1) A lifter that faces the cassette loading/unloading opening and urges the sheets stored in the cassette upward; a lifter moving drive means that moves the lifter upward in response to a sheet feeding signal; and a lifter that moves the lifter upward in response to a sheet feeding signal; A sheet feeding device comprising: a lifter descent restriction means for regulating the lifter descent; and a lifter descent restriction release member for releasing the restriction of the lifter descent restriction means when the cassette is removed.