JPH0130737B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feed device that feeds paper by flipping up the bottom plate of a paper feed cassette containing sheets, and particularly relates to a paper feed device that feeds paper by flipping up the bottom plate of a paper feed cassette containing sheets. Concerning a sheet sensing structure suitable for the device.

As is well known, in electrophotographic copying machines, etc.
A paper feeding device is used in which when a paper feeding cassette is mounted on a paper feeding tray, a flip-up member incorporated in the paper feeding tray flips up the bottom plate of the paper feeding cassette toward a paper feeding roller or the like.

By the way, in an electrophotographic copying machine using such a paper feeding device, it is necessary to confirm that there is recording paper in the paper feeding cassette before performing control operations, so a micro switch or the like is installed on the paper feeding roller. A detector is attached, and this detector detects the presence or absence of a sheet, such as recording paper, in the paper feed cassette. However, such a sheet sensing structure cannot be applied to a sheet feeding device in which the bottom plate is normally placed in a lowered state and is raised only when feeding sheets. Of course, in a paper feeding device having such a structure, it is also possible to detect the recording paper by placing a light emitting diode and a phototransistor facing the paper feeding tray while holding the paper cassette between them. , In such a structure, the detected value is low because the amount of peripheral light is relatively high.
Detection errors are likely to occur.

In view of the conventional situation as described above, the present invention proposes a structure that can be applied to a paper feeder whose bottom flips up only when feeding paper, and in which the paper feed cassette is loaded onto the paper feed stand. In a paper feed device having a flip-up mechanism that flips up the bottom plate of a paper feed cassette each time a paper is fed by a flip-up member provided on the paper feed tray at a position where the paper is fed A member is provided on the flip-up member, and a through hole is provided in a part of the bottom plate of the paper feed cassette for the sheet presence/absence detection member to detect the presence or absence of a sheet in the paper feed cassette.

Embodiments of the invention will now be described in detail with reference to the drawings.

The illustrated example is an embodiment in which the present invention is applied to a paper feed section of an electrophotographic copying machine. can be inserted. As shown in FIG. 4, the paper feed cassette 4 has a built-in bottom plate 5, that is, a mounting plate, on which a plurality of sheets, that is, recording papers X are placed in a stacked state. Can be done.

In FIG. 1, a fulcrum shaft 8 mounted on a side frame 7 is located at the bottom of the paper feed table 2, and the base of a flip-up member 9 is fixed to the center of the fulcrum shaft 8. This flip-up member 9 is the opening part 1 of the paper feed tray 2.
0 and the escape hole 11 of the paper feed cassette 4 (as shown in the fourth figure)
It leaks into the paper feed cassette 4 through the paper feed cassette 4 and flips up the bottom plate 5. A detector for sensing the recording paper X on the bottom plate 5 is provided near the tip of the flip-up member 9. For this purpose, a through hole 12 is made in a part of the bottom plate.
A light emitting element 13 and a phototransistor 14 whose irradiation field and light receiving field are directed toward the through hole 12 are fixed to the tip of the flip-up member 9 corresponding to the above.
Therefore, when the bottom plate 5 is lifted up as shown in FIG.
4, the presence of the recording paper X can be confirmed. In addition, at the shaft end of the fulcrum shaft 8,
As shown in FIGS. 2 and 5, a driven lever 16 biased by a tension spring 15 is fixed, and the attitude of this driven lever 16 is controlled by a control unit to be described later.

Returning to FIG. 1, a paper feed unit 18 is located inside and above the paper feed table 2 for feeding the recording sheets X in the paper feed cassette 4 into the paper feed path 17 one by one. This paper feeding unit 18 is connected to the side frame 7.
It is assembled to a parallel belt drive shaft 19 and a roller drive shaft 20 which are installed between them, and includes a drive pulley 21 fixed to the belt drive shaft 19 and a driven pulley 22 loosely fitted to the roller drive shaft 20. A conveyor belt 23 is provided which is stretched between the conveyor belt 23 and the conveyor belt 23. A paper feed roller 24 is fixed to the roller drive shaft 20, to which the recording paper X in the paper feed cassette 4 is pressed. Further, a peeling member 26 fixedly supported by the mounting plate 25 is slidably contacted on the surface of the conveyor belt 23 . Therefore, the bottom plate 5 of the paper feed cassette 4
When the paper is sprung up, the recording paper X in the paper feed cassette 4 is fed out by the rotational movement of the paper feed roller 24, and the recording paper X is moved toward the paper feed path 17 by the movement of the conveyor belt 23. and,
Due to the presence of the peeling member 26, the uppermost recording paper is peeled off from the other recording papers, and only the uppermost recording paper is sent to the paper feed path 17.

2 and 3 show the driven lever 1 described above.
6 shows a control unit 27 that controls the belt drive shaft 19 and the roller drive shaft 20, and this control unit 27 receives driving force from a drive gear 28. That is, the drive gear 28 has an input gear 30, a relay gear 31, and a first output gear 32 that are loosely fitted to the belt drive shaft 19, the support shaft 29 provided upright on the side frame 7, and the roller drive shaft 20, respectively. It is constantly rotating. An electromagnetic clutch 33 is attached to the belt drive shaft 19 and is energized by a paper feed start command signal given from the main body of the electrophotographic copying machine. When the electromagnetic clutch 33 is energized, the belt is driven from the input gear 30. Driving force is transmitted to the shaft 19. Further, a second shaft is provided at the shaft end of the belt drive shaft 19.
An output gear 34 is fixed, and this second output gear 34
rotates the driven gear 35 loosely fitted onto the support shaft 29.

On the other hand, the support shaft 29 has the driven lever 16
The base of a restraining member 36 that operates the is loosely fitted, and rotational force is transmitted from the second output gear 34 to this restraining member 36 via a spring clutch 37. As shown in FIG. 2, the restraining member 36 has two arms 36a and 36b, and a strong tension spring 39, one end of which is hooked to a pin 38 of the side frame 7, is hooked to the arm 36a. Further, the other arm 36b is connected to the roller 4 of the driven lever 16 described above.
It is assigned to 0. Therefore, in the demagnetized state of the electromagnetic clutch 33, the driven lever 16 moves against the force of the tension spring 15 to move the restraining member 3 as shown in the second figure.
6, the flip-up member 9 is lowered below the paper feed tray 2 as shown in the first diagram.

The spring clutch 37 has a sleeve 41 with a projection 41a, and a stopper 4 fixed to the side frame 7 is located in the movement range of the projection 41a.
2 is coming. Therefore, when the driven gear 35 is rotated by the second output gear 34 due to the excitation of the electromagnetic clutch 33, the arm 36b of the restraining member 36 is retreated out of the movement range of the driven lever 16, as shown in FIG. However, in this retreated state, the protrusion 41a
Since this hits the stopper 42, the rotational movement of the driven gear 35 is no longer applied to the restraining member 36, and the restraining member 36 is held in this retracted position.

A latch member 43 is loosely fitted to the support shaft 29.
The base of the latch member 43 is supported, and a spring 44 shown in FIG. 3 is provided between the latch member 43 and the restraining member 36. This latch member 43 has an engaging piece 4 that can be engaged with the side surface of the arm 36b of the restraining member 36.
5, and this engagement piece 45 is always seated on the arm 36b by the force of the spring 44. This latch member 43 is therefore driven by the movement of the restraining member 36.

Meanwhile, a spring clutch 46 is interposed between the first output gear 32 and the roller drive shaft 20, and a plurality of teeth 48 are formed on the circumferential surface of a sleeve 47 of the spring clutch 46. Within the range of motion of these teeth 48 are latches 43 which engage the teeth 48 to prevent rotation of the roller drive shaft 20 when the restraining member 36 is in the second illustrated rotational position.
A is facing me. Therefore, when the restraining member 36 is in the rotational position in which the driven lever 16 is released as shown in FIG. will be done.

Since the apparatus of the embodiment has the above-described configuration, when there is no sheet feeding start command signal, the driven lever 16 is pushed down to the position shown in the second figure by the restraining member 36, and the flip-up member 9 is moved to the second position. 1. Place it in the lowered position as shown. Therefore, in this state, the paper feed cassette 4 can be freely inserted into and removed from the paper feed tray 2, and this operation can be easily performed by simply holding the paper feed cassette 4.

Next, when a paper feed start command signal is applied from the main body of the electrophotographic copying machine, the electromagnetic clutch 33 is energized. Therefore, rotational motion is transmitted to the belt drive shaft 19 from the input gear 30 which is constantly rotating in the drive gear 28, and the drive pulley 21 transfers the rotational motion to the conveyor belt 2.
3 is driven. At the same time, belt drive shaft 1
9 is rotated, and the restraining member 36 is activated by the strong tension spring 39 via the driven gear 35 meshing with the second output gear 34 and the spring clutch 37.
It is rotated in the direction of arrow A in FIG. 2 against the force of.
For this reason, the driven lever 16 is flipped up by the force of the tension spring 15 as it moves toward the position shown in FIG.
Lift up the bottom plate 5.

As described above, when the recording paper X in the paper feed cassette 4 is pressed against the paper feed roller 24, the sleeve 4
Since the protrusion 41a of 1 collides with the stopper 42,
The spring clutch 37 opens and the restraining member 36
are held in the same position. Then, the latch 43a of the latch member 43 driven by the restraining member 36 is disengaged from the teeth 48 of the spring clutch 46. Therefore, the rotational motion of the first output gear 32, which is constantly rotating, is transmitted to the roller drive shaft 20 via the spring clutch 46, and the paper feed roller 24 starts rotating. As a result, the recording paper X in the paper feed cassette 4 is fed out by the paper feed roller 24, and the uppermost recording paper X is sent out to the paper feed path 17 one by one.

When feeding of the recording paper ends, the paper feeding start signal is no longer transmitted and the electromagnetic clutch 33 is demagnetized. Therefore, since the rotational force of the driven gear 35 is eliminated, the force of the tension spring 39 returns the restraining member 36 and the driven lever 16 to the position shown in the second figure.
Therefore, the flip-up member 9 returns to the position shown in the first figure, and the paper feed cassette 4 can be freely pulled out from the paper feed tray 2. The latch 43a engages with the teeth 48 of the spring clutch 46, so that the paper feed roller 24
stops. As a result, the paper feed cassette 4 can be replaced freely.

In the above embodiments, a detector consisting of a light emitting element 13 and a phototransistor 14 was illustrated, but the present invention is not limited thereto. It is also possible to fix it to the flip-up member 9.

After all, according to the present invention, since the detector is provided on the sheet flipping member, even a paper feeder of the type that flips up the sheet flipping member only when paper feeding starts.
It is possible to reliably sense the sheets in the paper feed cassette. Therefore, according to the paper feeding device of the present invention, paper feeding can be started after confirming that there is a sheet in the paper feeding cassette, so that it is possible to provide a paper feeding device that does not malfunction.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the paper feed section of an electrophotographic copying machine to which the present invention is applied, FIG. 2 is a side view of the paper feed section, and FIG. 3 is a cross-sectional view taken along the line - in FIG. FIG. 4 is a diagram corresponding to FIG. 1 at the time of paper feeding, and FIG. 5 is a diagram corresponding to FIG. 2 at the time of paper feeding. X...Recording paper, 2...Paper feed stand, 4...Paper feed cassette, 5...Bottom plate, 9...Flip-up member, 13...
...Light emitting element, 14...Phototransistor.

Claims (1)

[Claims] 1 At the position where the paper feed cassette is loaded into the paper feed tray,
In a paper feeding device having a flip-up mechanism that flips up the bottom plate of a paper feed cassette each time a sheet is fed by a flip-up member provided on a paper feed tray, a sheet presence/absence detection member for detecting the presence or absence of a sheet in the paper feed cassette is attached to the flip-up member. 1. A paper feeding device characterized in that a through hole is provided in a part of the bottom plate of the paper feeding cassette for the sheet presence/absence detecting member to detect the presence or absence of a sheet in the paper feeding cassette.