JPH0262453B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feeding device, and specifically to a bottom plate push-up mechanism of a paper feeding device using a paper feeding cassette.

In the case of a paper feeding device that uses a paper cassette, the level of the sheet decreases as the paper feeding operation progresses.
It is necessary to raise the movable bottom plate and bring the topmost sheet into contact with the paper feed roller.

Most conventional bottom plate lifting mechanisms have a spring-biased bottom plate lifting arm that contacts the bottom plate of the cassette, lifts the stacked sheets, and presses the topmost sheet against the paper feed roller. It's getting old. Incidentally, a frictional force necessary for feeding the sheet is required between the paper feed roller and the sheet. This frictional force is greatly influenced by the contact pressure between the two, in addition to the friction coefficient based on the shape and material of the paper feeding roller surface. For this reason, in conventional devices that push up the bottom plate using spring force, a phenomenon occurs in which the pressure between the sheets and the paper feed roller varies depending on the height of the sheets present in the cassette. Also, if there is a difference in mass due to the paper type, the pressure with the paper feed roller will change unless the spring force changes. When this pressure fluctuates,
A fatal malfunction occurs in the paper feeding device, such as non-feeding or double-feeding of sheets. For this purpose, conventionally,
It was difficult to select a spring to push up the bottom plate, which limited the number of sheets that could be stored in the cassette.

Furthermore, when attaching or detaching a cassette, there is an operation to retract the bottom plate push-up arm from the cassette storage section, and after attachment, in order to push up the bottom plate,
There is also an operation of swinging the arm. Furthermore,
When a spring is used, an impact sound and a vibration sound of the spring are generated due to the swinging operation of the bottom plate push-up arm.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bottom plate push-up mechanism for a paper feeder that solves the various problems described above.

An object of the present invention is to provide a paper feed roller that rotates in the paper feed direction and a paper feed cassette whose tip is positioned below the paper feed roller, and to swing the bottom plate of the paper feed cassette. A paper feeding device that raises the uppermost sheet of the sheets stored in the cassette and brings it into contact with the paper feeding roller, a cassette holder that removably holds the paper feeding cassette, and a cassette mounted thereon. a swingable bottom plate push-up arm disposed with its free end corresponding to the lower surface of the bottom plate; a swing lever that is substantially integral with the push-up arm; and a first swing lever that engages with the swing lever. a rotary body selectively located in a position and a second position in which it is not engaged with the lever; a driving means for rotationally driving the rotary body in a direction for raising the swinging lever; When the cassette is attached to the holder, this is detected and the rotating body is positioned at the first position, and when the cassette is removed from the holder, this is detected and the rotating body is positioned at the second position. and a level detection means for detecting the level of the sheets stored in the cassette and outputting a signal to rotate the rotating body when there are no sheets at a predetermined level. This is achieved by the unique bottom plate push-up mechanism.

According to the present invention, the arm or lever directly pushes up the bottom plate without using the elasticity of a spring, so the pressure contact force between the sheet and paper feed roller can be kept constant regardless of the height of the sheet in the cassette. It is possible to stably hold the paper within the range of , that is, within the range of the own weight of the paper feed roller. By stabilizing the paper feeding pressure, non-feeding or double feeding of sheets can be prevented. If it is assumed that the coefficient of friction will change as the type of paper changes, it goes without saying that a mechanism for changing the roller pressure may be added to ensure reliable feeding. Furthermore, since the bottom plate push-up arm swings depending on the presence or absence of a cassette, the user is freed from the operation of pushing the bottom plate push-up arm when installing a cassette. The fact that there is no such operation, together with the fact that no springs are used, eliminates the generation of unpleasant noises such as impact sounds from arms, levers, bottom plates, etc., and vibration sounds from springs.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In FIGS. 1 to 4, on the base 1,
A pair of side plates 2 and 3 are fixed. Side plates 2, 3
An upper stay 4 and a lower stay 5 are each supported between them. The illustrated embodiment is a paper feeding device in which cassettes 6 and 7 can be set in two stages, upper and lower. Therefore, an upper sheet feeding mechanism 8 and a lower sheet feeding mechanism 9 are provided corresponding to each cassette. Each paper feeding mechanism 8, 9 is selectively operated by selecting a cassette containing sheets of a desired size. The sheets sent out by the upper paper feed mechanism 8 are
The sheet guided to the main sheet passage 11 through the upper sheet passage 10 and fed out by the lower sheet feeding mechanism 9 passes through the lower sheet passage 12 to the main sheet passage 11.
be led to.

A sensor 13 is disposed in the main sheet path 11 to detect the leading edge of the fed sheet and output a signal to turn off the rotation of a paper feed roller, which will be described later. Further, a pair of registration rollers 14 is arranged in the passage 11. This pair of registration rollers 14 feeds the sheet in accordance with the copying process of the main body of the copying machine (not shown). Each of the above-mentioned seat passages has guide plates 15, 16, 1, respectively.
It is formed by 7,18. As shown in FIG. 2, one end 16a of the guide plate 16 extends to the right in the figure (see FIGS. 5 and 9). Further, one end 18a of the guide plate 18 extends in the same manner, and each one end 16a, 18a is located near the front plate of the attached paper feed cassette. Note that the guide plates 15 to 18 are shown in FIG. 1, FIG. 3,
Not shown in FIG.

As shown in FIGS. 4 and 5, the base 1 includes
Cassette holders 19 and 20 are erected along side plates 2 and 3. Above holder 1
Holding grooves 22 and 23 are formed on opposing surfaces of the cassettes 9 and 20, respectively, into which engaging portions 21 (only one of which is shown in FIG. 6) provided on both sides of the tip of the cassette are engaged. As shown in FIG. 6, the holding grooves 22 and 23 have grooves that abut against the stepped portion 21a of the engaging portion 21.
Stopper portions 22a, 2 that maintain the position of the cassette
3a are formed respectively.

A feed roller drive shaft 25 is rotatably supported between the side plate 3 and a bracket 24 fixed to the lower surface of the stay 4 substantially in the center. A sprocket 27 and a gear 28 are attached to the shaft end protruding from the side plate 3 via an electromagnetic clutch 26. Sprocket 27 and gear 28 are substantially integral.

A feed roller 31 is fitted to the other end of the feed roller drive shaft 25 via a gear 29 fixed to the shaft and a one-way clutch 30, respectively.
The feed roller 31 consists of a high friction part 31a made of rubber or a rubber-like product and a hub part 31b. When the drive shaft 25 rotates, the one-way clutch 30 transmits this rotation to the feed roller 31, but even if the same shaft does not rotate, when a force to rotate the feed roller 31 is applied, it allows the roller to rotate. It acts in the direction.

A detection rod 34 is rotatably supported at both bent ends of the drive shaft 25 via bearings 32 and 33. Support arm 35 at one end of the detection rod 34
Support shafts 36 and 37 are fixedly planted in the. Support shaft 3
A gear 38 that meshes with the gear 29 is rotatably supported at 6, and a gear 39 that meshes with the gear 38 is rotatably supported on the support shaft 37. A pre-fed roller 40 is supported on the support shaft 37 . This pre-fed roller 40 consists of a high friction part 40a made of rubber or a rubber-like product, and a hub part 40b integrated with the gear 39. In addition, in FIG. 4, the pre-fed roller 4 is shown for convenience of illustration.
0, gears 38 and 39 are not shown. As shown in FIG. 9, the pre-feed roller 40 is located above the tip of the mounted cassette.

A passive arm 41 is formed at the other end of the detection rod 34 . A switch actuating member 42 is fixed to the actuating arm 41. This actuating member 42 protrudes outward from a hole 43 (see FIG. 3) formed in the side plate 3, and is positioned so as to be able to abut against an actuating piece 44a of a micro switch 44 fixed to the side plate.

When no cassette is attached, the detection rod 34 swings due to the weight of the pre-feed roller 40, etc., and the operating member 42 turns on the switch 44.

A separation drive shaft 46 is rotatably supported between a bracket 45 fixed to a substantially central portion of the upper surface of the upper stay 5 and the side plate 3. A gear 47 that meshes with the gear 28 either directly or via a speed increasing gear train (not shown) is fixed to one end of the drive shaft 46. At the other end 46a of the drive shaft 46,
A sleeve 49 to which the support arm 48 is fixed integrally is rotatably inserted, and a gear 50 is integrally inserted therein. A support shaft 51 is fixed to the support arm 48. This shaft 51 includes a gear 52 that meshes with the gear 50, and a drive sleeve 5 that is integrated with the gear 52.
3, a driven sleeve 54, and a separation roller 55 integral with this sleeve are rotatably inserted. The separation roller 55 is composed of a hub part integral with the driven sleeve 54 and a high friction part made of rubber or a rubber-like material tightly fitted to the outer periphery of the hub part. A spring 56 is wound around the outer periphery of each of the driving sleeve 53 and the driven sleeve 54.

The sleeves 53, 54 and the spring 56 constitute a clutch, and when the gear 52 rotates, the spring 56 is tightened and the driven sleeve 54 is rotated. However, if a load exceeding a predetermined value is applied to the driven sleeve 54, the sleeve will not be rotated. In other words, the separation roller 55 is driven via a torque limiter. The rotation of the separation roller 55 will be described later.

The separation roller 55 is biased toward the feed roller 31 by a biasing means (not shown).
The movement behavior is given in the direction in which it comes into contact with the object.

A bottom plate push-up shaft 58 is provided between the bracket 57 fixed to the bent lower stage 5a of the lower stay 5 and the side plate 3.
is rotatably supported. A base end of a bottom plate push-up arm 59 is fixed to one end 58a of the push-up shaft 58. A swing lever 60 is fixed to the other end 58b of the push-up shaft 58. The swing lever 60 is
It extends along the side plate 3, and the side surface 60a next to the side plate 3 is a sloped portion as clearly shown in FIG.

On the other hand, a rotating body 61 is rotatably provided on the side plate 3 near the free end of the swing lever 60. Teeth that mesh with the idle gear 62 are formed on the outer periphery of the rotating body 61. Rotating body 6
1 is supported by fitting a large diameter portion 63a of a shaft 63 integrally press-fitted into a bearing 64 fixed to the side plate 3 so as to be rotatable and slidable in the axial direction. The bearing 64 has flanges 64a and 64b.
are fixed to the side plate 3 by spring guide shafts 65 and 66. As shown in FIGS. 1, 3, and 7, a presser plate 67 is slidably fitted into the guide shafts 65, 66, facing the end of the large diameter portion 63a. A spring stopper 6 provided at the plate and each shaft end
8, 69, an extensible helical spring 70, 7
1 is wrapped. Therefore, in the rotating body 61,
The elasticity of the springs 70 and 71 gives the side plate 3 a tendency to move inwardly. In addition, the swing lever 60 of the rotating body 61
In the case of the illustrated embodiment, two engaging pins 72 and 73 are fixed and protruded from the end face facing the. The small diameter portion of the shaft 63 press-fitted into the rotating body 61 is
The protruding portion 63b is slightly protruded from the boss portion.

As shown in FIG. 1, a bearing stage 5b is formed near the side plate 3 of the bent lower stage 5a of the lower stay 5, and a support shaft 74 is fixedly planted here. A cassette detection lever 75 is rotatably mounted on the support shaft 74 at its boss portion 75a. The detection end 76 at one end of the detection lever 75 is positioned facing the rear opening 22b of the holding groove 22 of the cassette holder 20, as shown in FIGS. 5 and 6. The operating arm 77 of the detection lever 75 extends to a position where it can abut against the protrusion 63b of the rotating body 61. As shown in FIG. 3, the actuating arm 77 has entered the recess 20a of the cassette holder 20, and is moved around the support shaft 74 by the elasticity of a spring 78 loaded between it and the cassette. ,
It is given a swinging behavior in which the free end is brought into abutment with the protrusion 63b.

The elasticity of the spring 78 is set larger than that of the springs 70 and 71. for that,
The rotating body 61 is pushed by the detection lever 75 and is positioned toward the side plate 3 (second position). This position will be described later.

By the way, what has been explained so far is about the upper paper feed mechanism 8, but the lower paper feed mechanism 9 is also explained.
The only difference is whether the arrangement position is between the upper stay 4 and the lower stay 5 or between the lower stay 5 and the base 1, and each structure is the same. Therefore, regarding the lower paper feed mechanism 9, the explanation of the individual configurations will be omitted, and the number of the corresponding mechanism 8 will be 900.
Just add the sign of the sum of . However, regarding the lower paper feeding mechanism 9, some members are not shown in order to avoid complication of the drawing display.

A synchronous motor 79 is fixed to the side plate 3, and a drive gear 81 is fixed to its output shaft 80. This drive gear 81 meshes with the idle gear 62 and the teeth of a rotating body 961 of the lower paper feeding mechanism, respectively. The motor 79 is operated by a select switch that selects either the upper cassette 6 or the lower cassette 7 (see Figure 2) to feed paper.
It is designed to rotate in the opposite direction.

In FIG. 8, when the output shaft 80 of the motor 79 rotates in the direction of the solid line arrow, the rotating body 961 meshing with the drive gear 81 and the idle gear 62 rotate in the direction of the solid line arrow. The body 61 also rotates in the direction of the solid arrow. The motor 79 rotates in this direction when the lower cassette 7 is selected, and when the upper cassette 6 is selected, the motor 79 rotates in the direction of the dashed arrow.

When the cassette is not attached, the rotating body is activated by the actuating arm 977 which is biased by the spring 978, as shown in FIG.
It is pushed against the elasticity of 971. In this position, even if the rotating body 961 rotates, the engagement pin 972
973 is in the second position where it does not engage the swing lever 960. When the cassette is installed, the rotating body 6
1, which will be described in detail later, assumes a second position in which either one of the engagement pins 72, 73 is positioned so as to be able to engage with the swing lever 60.

In other words, the rotating body 61, the members attached thereto, the cassette detection lever 75, and the swinging lever 60 constitute a kind of clutch mechanism.
Hereinafter, as shown in FIG. 7, the clutch mechanism of the upper sheet feeding mechanism 8 will be referred to as an upper clutch 800, and that of the lower sheet feeding mechanism 9 will be referred to as a lower clutch 900. Therefore, in FIG. 7, the upper clutch 800 is articulated,
The rotating body 61 is in the first position,
The lower clutch 900 is disconnected and the rotating body 961
is in the second position.

Referring to FIG. 8, the drive system will be explained. a sprocket 83 fixed to the output shaft of the drive motor 82;
A sprocket 85 attached to the drive shaft 84 of the registration roller pair 14, a feed roller drive shaft 25,
A chain 86 is wound around the sprocket 27, 927 attached to the sprocket 925. The registration roller pair sprocket 85 is attached to the drive shaft 84 via an electromagnetic clutch 87, as shown in FIG. The electromagnetic clutch 87 is turned on according to the copying process to transmit the rotation of the sprocket 85 to the drive shaft 84, and is turned off after a predetermined time after the sensor 13 (see FIG. 2) detects the sheet leading edge to prevent the rotation of the pair of registration rollers. stop.

When the drive motor 82 is energized, the chain 86 rotates to rotate the sprockets 85, 27, 927 in the direction of the chain arrow. Sprocket 27,9
The rotation of 27 is caused by gears 28, which are substantially integrated therewith.
Through 928, gear 47 (see FIG. 3), 94
Rotate 7. The rotation of the gears 47, 947 is transmitted to the gears 50, 950 by the separation roller drive shafts 46, 946, causing the gears 52, 952 meshing therewith to rotate in the direction of the dashed arrow. The rotation of the gear 52, 952 is transmitted to the separation roller 55, 955 via the drive sleeve 53, spring 56, and driven sleeve 54. The roller 55,9
Assuming that no load greater than the torque exerted by the spring 56 is applied to the roller 55, the roller rotates in the direction of arrow B. This torque limit will be described later.

As mentioned above, the separation roller drive shaft 4
6,946 is constantly rotated.

On the other hand, the feed roller drive shaft 25, 925 is
It is selectively rotated by an electromagnetic clutch 26, 926 which is linked to the selection operation of the upper and lower cassettes and which is turned on and off according to the sheet leading and trailing edge detection (or copying process) by the sensor 13 (see Figure 2). I am made to do so.

Assuming that the upper cassette is selected,
When the paper feed signal is issued, the electromagnetic clutch 26 is energized. When the clutch 26 is turned on, the rotation of the sprocket 27 and gear 28 is caused by the rotation of the feed roller drive shaft 2.
5, and the feed roller 31 rotates in the direction of the solid arrow via the one-way clutch 37 (see FIG. 3). Further, the rotation of the drive shaft 25 is controlled by the gear 2
9, 38, 39, pre-fed roller 40
Rotate in the direction of the solid arrow (feeding direction).

A separation roller 55 is brought into contact with the rotating feed roller 31 with a predetermined normal force. Since the torque applied by the feed rollers 31 to the separation rollers 55 by contacting each other is greater than the torque by the springs 56 (see FIG. 3), the separation rollers 55
It rotates in the direction of arrow F following the feed roller 31. The separation roller 55 rotates in the direction of arrow F in the same manner when a single sheet is held between the feed roller 31 and the feed roller 31. However, for example, when two sheets enter between both rollers 31 and 55, the force of the spring 5 is greater than the torque generated between the sheets.
6 is larger, so the separation roller 55 rotates in the direction of arrow B. Therefore, the sheet in contact with the separation roller is pushed back in the opposite direction to the sheet feeding direction.

The prefeed roller 40 pulls out the cassette, and the separation roller 55 and feed roller 31
The separated sheets travel through the sheet path and are detected by a sensor 13 (see FIG. 2). After a predetermined period of time has elapsed since this sheet detection signal,
That is, when the time elapses from when the leading edge of the sheet is detected until it is gripped by the pair of registration rollers 14, the power to the electromagnetic clutch 26 is cut off.

Thereafter, the sheet is conveyed by a pair of registration rollers 14 that rotate according to the copying process. The feed roller 31 and the separation roller 55 follow the advancing sheet. At this time, since the feed roller 31 is rotated by the action of the one-way clutch 30, the pre-feed roller 40 is not rotated.

The operation of the bottom plate push-up mechanism will be explained.

When no cassette is attached to the cassette holders 19, 20, the bottom plate push-up arms 59, 959
As shown in FIG. 2, it is lowered by its own weight or by the action of a spring (not shown), and is placed in a position where it does not obstruct the entry of the cassettes 6, 7.

On the other hand, the clutch mechanism is in the form of a lower clutch 900 shown in FIG. That is, spring 9
The rotating body 961 is pushed and moved by the actuating arm 977 energized by the actuator 78, and the engaging pins 972, 973
is placed in a second position where it cannot engage with the swing lever 960. Prefed Koro 40,940 is
The switches 44 (see Figure 1) and 944 (see Figure 9) rotate around the drive shafts 25 and 925.
is turned on.

Also, the detection end 76 of the cassette detection lever 75
As shown in FIGS. 3 and 6, the holder 20
It is located at the back opening 22b of the holding groove.

Now, as shown in FIG. 6, the cassette 6 is pushed toward the holder 20, the engaging portion 21 is fitted into the holding groove 22, and then the stepped portion 21a is placed in the holding position where it is engaged with the stopper 22a. . In this holding position, the tip pushing portion 21 of the engaging portion 21
b collides with the detection end 76 (see FIG. 7), causing the cassette detection lever 75 to swing around its axis 74.

Due to the swinging of the detection lever 75, the rotating body 61, which had been pushed and moved by the actuating arm 77 and placed in the second position, slides due to the elasticity of the springs 70 and 71, and moves to the seventh position. The upper clutch 800 shown is in a first position. In this first position, the swing lever 60 is located on the rotation locus of the engagement pins 72 and 73. When the cassette 6 is installed in the fixed position, the free end of the bottom plate push-up arm 59 has entered the bottom hole 6a of the cassette 6.
It faces the lower surface of the movable bottom plate 6b.

At this time, the uppermost sheet of the sheet bundle stacked on the bottom plate 6b and the pre-feed roller 40 are separated from each other. Therefore, the micro switch 44 is pushed by the actuating member 42 (see FIGS. 1 and 4), turning on the motor 79 (see FIG. 8). Since paper feeding from the upper cassette is selected, the output shaft of the motor 79 rotates in the direction of the broken line in FIG. 8 (in the direction of the solid line in FIG. 9).

Therefore, the rotation of the motor 79 is controlled by the gears 81 and 62.
The rotating body 61 is rotated clockwise in FIG. When the rotating body 61 rotates, the engagement pin 73 fixed on the end face of the rotating body 61 moves into the swinging lever 60.
The lever 60 is raised and moved together with the push-up shaft 58, as shown in FIG.

As the push-up shaft 58 rotates, the bottom plate push-up arm 59, which is integrated with the push-up shaft 58, rotates, and its free end touches the bottom plate 6.
b is pushed up together with the sheet bundle S placed thereon. The action of pushing up the bottom plate 6b is caused by the uppermost sheet Sa colliding with the lower peripheral surface of the pre-feed roller 40, pushing up the roller, swinging the support arm 35, the detection rod 34, and the actuating arm 41, and operating the switch. This continues until the member 42 releases the pushing operation of the switch operating piece 44a as shown in FIG. In addition, the switch operating member 4 in FIG.
2 and the actuating piece 44a are shown in an exaggerated manner.

When the switch 44 is released, the motor 7
9 (see FIG. 8) is cut off, and the rotating body 61
rotation is stopped. At this time, sufficient pressure is generated between the uppermost sheet Sa and the pre-feed roller 40 to feed the sheet.

Then, when the electromagnetic clutch 26 is energized at the same time as a paper feed command, for example, when a print button is pressed to start copying, or at an appropriate timing, the feed roller drive shaft 25 rotates and feeds the feed roller 31 and pre-feed roller 40. direction. At this time, although the separation roller drive shaft 46 is rotating counterclockwise in FIG. 9, the separation roller 40 is rotated due to the action of the torque limiter.
It is driven by the feed roller 31 and rotates in the direction of arrow F.

Prefed Colo 40 is the top seat Sa
When the sheet is pulled out and sent between the rollers 31 and 55, the rollers convey the sheet from the upper sheet passage 10 to the main sheet passage 11. After a predetermined period of time has elapsed after the leading edge of the sheet is detected by the sensor 13, the electromagnetic clutch 26 is de-energized and the feed roller drive shaft 25 is stopped. Therefore,
The pre-feed roller 40 stops rotating.

As the copying process progresses, the registration roller pair 14 rotates and the sheet is conveyed again.
Feed roller 31 and separation roller 55 are
It is accompanied by the sheet being conveyed.

By the way, the pre-feed roller 40 does not necessarily feed a single sheet from a sheet bundle. For example, if two sheets are fed out and their leading ends are fed between the feed roller 31 and the separation roller 55, the uppermost sheet receives friction from the feed roller 31 and is fed in the feeding direction. However, the next sheet that is in contact with the separation roller 55 receives a torque larger than that obtained by the sheets and is urged in the direction of arrow B (see Fig. 9). Therefore, it is sent back in the opposite direction to the feeding direction. When the next sheet leaves the contact area between the rollers 31 and 55, the separation roller 55 rotates in the direction of arrow F due to friction with the upper sheet. The next sheet is dragged by the topmost sheet and tries to move in the same direction, but every time it enters between the two rollers, it is pushed back.

As the sheet feeding operation progresses, the level of the sheets in the cassette becomes progressively lower, and the pre-feed roller 40 lowers accordingly. The lowering of the roller 40 lowers the switch operating member 42 via the support arm 35, the detection rod 34, and the operating arm 41, and pushes the operating piece 44a of the switch 44. As a result, the motor 79 resumes rotation, rotates the rotating body 61, and lifts and swings the bottom plate push-up arm 59. The rotation of the motor 79 is stopped when the switch 44 is turned off (see FIG. 10). This operation of pushing up the bottom plate 6b is performed intermittently while the sheet is being fed.
Note that when the sheet level is lowered and the pre-feed roller 40 descends to activate the switch 44, there is a gap between the roller 40 and the highest sheet.
Needless to say, sufficient pressure is ensured to feed the sheet.

In the case of the illustrated embodiment, it is a two-stage cassette system, and when the upper paper feeding mechanism 8 is operating, the lower paper feeding mechanism 9 only rotates the separation roller drive shaft 946, and the other parts are rotated. Not working. However, when the bottom plate is pushed up with respect to the upper cassette 6, the rotating body 961 engaged with the gear 81 of the motor 78 is rotated.

If the lower cassette is not installed,
As shown in FIG. 7, since the lower clutch 900 is disengaged, the rotating body 961 is placed in the second position.
Even if the lever rotates, the engagement pins 972 and 973 do not engage with the swing lever 960.

When a cassette is installed in the lower stage, the lower clutch 900 is replaced by the upper clutch 80 shown in FIG.
0, the rotating body 96
1 has been moved to the first position. Furthermore, when the upper cassette is selected, the rotating body 961 rotates counterclockwise as shown in FIG.
It rotates in a direction to engage with the upper surface of 60. but,
Since the side surface of the swing lever 960 facing the rotating body is formed into an inclined surface 960a, the pin 9
72 and 973 avoid engagement with the lever by abutting against the inclined surface and moving the rotating body 961 along this in the axial direction against the elasticity of the springs 970 and 971.

If the lower cassette is selected, the upper paper feed mechanism operates in the same manner as described above.

Next, the effect when the cassette is removed will be explained.

When the mounted cassette 6 is pulled out from the cassette holders 19, 20 as shown in FIG.
6 is disengaged. The detection lever 75 whose detection end 76 is released from the restraint swings due to the elasticity of the spring 78, and the operating arm 77 moves the rotating body 61 to the second position (see the lower clutch 900 shown in FIG. 7). Push it. When the rotating body 61 moves in the axial direction, the engagement pin 73 (see FIG. 9) that has been engaged with the lower surface of the swing lever 60 also moves, releasing the bottom plate pushing-up operation.

By moving the engagement pin 73, the swing lever 60
falls and swings together with the bottom plate push-up arm 59 that receives the weight of the bottom plate 6b and the seat S. This causes the arm 59 to separate from the bottom plate 6b.

In other words, just by pulling out the cassette slightly,
The operation of pushing up the bottom plate is released, the bottom plate push-up arm descends, and the cassette can be removed without any hindrance.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of an example of a paper feeding device to which the bottom plate push-up mechanism of the present invention is applied, FIG. 2 is a side view of the same, FIG. 3 is a developed plan view of the main parts of the same, and FIG. is a front view of the same as above, FIG. 5 is a perspective view of essential parts of the same as above, FIG. 6 is a perspective view showing the positional relationship between the cassette detection lever and the cassette, and FIG. , FIG. 8 is a side view schematically showing the drive system, FIG. 9 is a side view showing the operation of pushing up the bottom plate, and FIG. 10 is a side view showing the operation of the seat level detection means. 6, 7...cassette, 8...upper paper feeding mechanism, 9...
...Lower paper feed mechanism, 6b...Bottom plate, 19,20...Cassette holder, 31,931...Feed roller, 40,940...Pre-feed roller, 55,
955...Separation roller, 34...Detection rod, 42...Switch operating member, 44...Switch, 59,959...Bottom plate push-up arm, 60,9
60... Swinging lever, 61,961... Rotating body,
72, 73, 972, 973...Engagement pin, 7
5,975...Cassette detection lever, 79...Motor.

Claims (1)

[Claims] 1. A paper feed roller that rotates in the paper feed direction and a paper feed cassette whose tip is positioned below the paper feed roller, and a movable bottom plate of the paper feed cassette. A paper feeding device that swings up and brings the uppermost sheet stored in the cassette into contact with the paper feeding roller, and a cassette holder that removably holds the paper feeding cassette; a swingable bottom plate push-up arm disposed with its free end corresponding to the lower surface of the bottom plate of the cassette; a swing lever that is substantially integral with the push-up arm; and a second swing lever that engages with the swing lever. a rotating body that is selectively located in a first position and a second position that does not engage the lever; a drive means that rotationally drives the rotating body in a direction that raises the swinging lever; When the cassette is attached to the holder, this is detected and the rotating body is positioned at the first position, and when the cassette is removed from the holder, this is detected and the rotating body is positioned at the first position. a cassette detection lever positioned at position 2; and level detection means for detecting the level of the sheets stored in the cassette and outputting a signal to rotate the rotating body when there are no sheets at a predetermined level. The bottom plate push-up mechanism is characterized by: 2. A patent characterized in that the rotating bodies are capable of forward and reverse rotation, and that when the rotating bodies rotate in the opposite direction to the direction in which the swinging lever is pushed up, the rotating bodies retreat from the swinging lever and do not engage with each other. A bottom plate push-up mechanism in a paper feeder according to claim 1.