JPH115633A - Paper feed device and image forming device provided with paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feed device which is capable of appropriately controlling the lowering speed of a bottom plate of a paper feed tray when the bottom plate is lowered, prevent colliding sound, deformation of the bottom plate, or flapping of paper sheets, and which is, provided with a simply structured and inexpensive braking mechanism. SOLUTION: With the paper feed device, after a paper feed tray 1 is drawn out from an image forming device to lower a bottom plate 2, and paper sheets are supplied on the bottom plate 2, the bottom plate 2 is raised up to a paper feed position so that the paper sheets can be fed to the image forming device. In this case, the paper feed device is provided with a driven shaft 3 which is engaged with a driving shaft of the image forming device to be driven, and a gear train braking mechanism 9 consisting of a gear 11 provided on the driven shaft 3, and plural braking gears which are engaged with the gear 11 to give braking load torque to the rotation of the driven shaft 3 following a decent of the bottom plate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding tray which is pulled out of an image forming apparatus and replenishes sheets. More specifically, the present invention relates to a sheet supply apparatus capable of feeding a sheet to an image forming apparatus by raising a bottom plate to a sheet supply position, and an image forming apparatus including the sheet supply apparatus.

[0002]

2. Description of the Related Art When a paper tray is pulled out of an image forming apparatus and paper is replenished, a paper feeding apparatus of a type capable of replenishing paper by lowering a bottom plate on which the paper is placed, particularly paper In a large-capacity paper supply device capable of storing 1,000 sheets or more, when a large amount of sheets are placed on the bottom plate and the paper feed tray is pulled out, the lowering speed of the bottom plate increases due to its weight. As a result, problems such as noise, deformation due to collision of the bottom plate with the lower portion of the paper supply device, and flapping of the paper in the paper supply device occur.

[0003] To cope with the above-mentioned problem, many large-capacity paper supply devices have been proposed in which a brake is applied when the bottom plate of the paper feed tray descends to control the descending speed of the bottom plate. Have been. For example, Japanese Patent Application Laid-Open No. 6-156754 discloses that the bottom plate descends by its own weight to a certain position, and that a constant load torque is applied when descending from the bottom plate to the lowest position. Japanese Unexamined Patent Publication No. 6-156754 discloses that a one-way damper mechanism is provided, which uses a coil spring and twists the coil spring when the bottom plate descends to brake the driven shaft. There is disclosed a brake mechanism in which a coil spring is loosened when ascending to provide no load.

Further, as shown in FIG. 6, a gear 25 is provided on a driven shaft 24 provided with a pulley 23 for winding up a wire 22 connected to a bottom plate 21, and a flywheel is coaxial with a gear 26 meshing with the gear 25. 27, the lowering speed when the bottom plate starts lowering is reduced. As shown in FIG. 7, a gear 28 with a one-way clutch is provided on the driven shaft 24, and a gear 29 meshing with the gear 28 is provided. A centrifugal brake 30 is provided coaxially with the centrifugal brake 30 so that when the lowering speed of the bottom plate increases, the centrifugal brake 30 reduces the speed.

However, the one provided with the one-way damper mechanism disclosed in Japanese Patent Application Laid-Open No. 6-156754 is unavoidable to be expensive because the one-way damper mechanism itself is a special mechanism. JP-A-6-15675
In the apparatus using the coil spring disclosed in Japanese Patent Publication No. 4 (1994), since the bottom plate is balanced with the coil spring when descending, there is a problem that the bottom plate moves up and down when replenishing paper, making it difficult to supply.

On the other hand, the apparatus provided with the flywheel 27 shown in FIG. 6 cannot stop at the lowest position due to the inertia of the flywheel 27 because the lowering distance of the bottom plate becomes large in a large-capacity sheet feeding apparatus. However, there is a problem that the centrifugal brake 30 shown in FIG. 7 is provided with a problem that the centrifugal brake 30 is very expensive and causes an increase in cost.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is particularly applicable to a large-capacity sheet feeding apparatus. When a bottom plate of a paper feed tray is lowered, the lowering speed of the lower tray is appropriately controlled so that a collision sound or a bottom plate is generated. It is an object of the present invention to provide a paper supply device which can prevent deformation of the paper or flapping of the paper and stabilize the bottom plate at a predetermined lowering position, thereby facilitating the supply of paper. Another object of the present invention is to provide a paper feeding apparatus having a braking mechanism capable of appropriately controlling a lowering speed of a bottom plate of a paper feed tray and having a simple and inexpensive manufacturing mechanism. It is in. A further object of the present invention is to provide an image forming apparatus provided with a large-capacity sheet feeding device capable of appropriately controlling the descending speed of a sheet feeding tray.

[0008]

In order to solve the above-mentioned problems, a paper supply apparatus according to the present invention lowers a bottom plate by pulling out a paper supply tray from an image forming apparatus, and replenishes paper on the bottom plate. Then, in a paper feeding apparatus capable of feeding paper to the image forming apparatus by raising the bottom plate to a paper feeding position, a driven shaft of the paper feeding apparatus driven by being engaged with a driving shaft of the image forming apparatus. And a gear provided on the driven shaft, and a gear train braking mechanism comprising a plurality of braking gears meshed with the gear and applying a braking load torque to rotation of the driven shaft accompanying the lowering of the bottom plate. When the bottom plate descends, a braking load torque is applied to the driven shaft by increasing the sliding resistance due to the engagement between the braking gears of the gear train braking mechanism when the bottom plate descends. The descent speed can be adjusted. Conversely, when the bottom plate rises, the braking load torque is released by reducing the bite between the braking gears and reducing the sliding resistance, and the bottom plate is raised as a no-load condition. Can be.

Further, in the paper supply device according to the present invention, in the above-described paper supply device, the gear train braking mechanism may be combined with at least three stages of braking gears.
Means for increasing the engagement of both brake gears only when the bottom plate is lowered, between the second-stage brake gear and the third-stage brake gear. Only when there is a means to increase the engagement between the second and third brake gears, the brake and the one-way clutch are provided by a gear train braking mechanism having a simple structure composed of a combination of three brake gears. The following two functions can be provided.

Further, in the paper supply apparatus according to the present invention, in the paper supply apparatus described above,
The second stage brake gear is supported by a link mechanism that can swing about the rotation center of the first stage brake gear. By making the link mechanism that supports the braking gear swingable and swinging in the direction in which the braking gear bites when the bottom plate is lowered and in the opposite direction when the bottom plate is raised, the above two functions can be easily realized. .

Further, the paper supply device according to the present invention,
In the above-described paper supply apparatus, the swing regulation means of the link mechanism is constituted by a stopper which swings and contacts the link mechanism when the bottom plate is raised to the paper feeding position. Therefore, the swing of the link mechanism can be stopped at a position where the engagement of the second-stage brake gear and the third-stage gear does not completely separate.

Further, in the image forming apparatus according to the present invention, the bottom plate is lowered by pulling out the paper feed tray,
In the image forming apparatus provided with a paper supply device capable of feeding by raising the bottom plate to the paper feeding position after replenishing the paper on the bottom plate, the image forming apparatus is engaged with a drive shaft of the image forming device. A driven shaft of the driven paper supply device, a gear provided on the driven shaft, and a plurality of gears meshed with the gear to apply a braking load torque to the rotation of the driven shaft accompanying the lowering of the bottom plate. A gear train braking mechanism comprising a braking gear, and an image forming means for forming an image on a sheet fed by the sheet feeding device are provided. The structure is simple and can be manufactured at low cost. By providing the braking mechanism, it is possible to easily perform the operation of replenishing a large number of sheets to the image forming apparatus.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
A description will be given based on FIGS. FIG. 1 is a plan view showing a configuration of a main part of a paper feeding apparatus according to an embodiment of the present invention.
FIG. 3 is a side view, FIG. 3 is a plan view showing a configuration of the gear train braking mechanism, and FIG. 4 is a side view thereof.

In FIG. 1, reference numeral 1 denotes a paper feed tray of a large-capacity paper supply device applied to an image forming apparatus, and the paper feed tray 1 has a bottom plate 2 provided inside and movable up and down. A large amount of paper can be placed on top and fed. Reference numeral 3 denotes a driven shaft rotatably provided on one side of the sheet feeding device. A winding pulley 4 is attached to each of both ends of the driven shaft 3, and a wire 5 having one end connected to the pulley 4 is provided. By connecting the other end to the bottom plate 2 via pulleys 6 and 7,
Is configured to be able to move up and down.

A pin 8 is provided at one end of the driven shaft 3 for engaging and disengaging from a groove of a coupling driven by a motor (not shown). When the sheet feeding tray 1 is set in the image forming apparatus, the pin 8 is The bottom plate 2 is raised to a predetermined paper feeding position by driving the motor by engaging with the groove of the ring, so that paper can be supplied to the image forming apparatus. On the other hand, when the paper feed tray 1 is pulled out from the image forming apparatus, the driven shaft 3 becomes free to rotate by the pin 8 being removed from the groove of the coupling. Free fall is possible depending on the weight of the paper placed.

A gear train braking mechanism 9 for adjusting the descending speed when the bottom plate 2 descends is provided on the other end side of the driven shaft 3. The gear train braking mechanism 9
A gear 11 attached to the end of the paper feed tray 1 via a bracket 10 and provided at the other end of the driven shaft 3.
And a plurality of braking gears 1 that apply a braking load torque to the rotation of the driven shaft 3 accompanying the lowering of the bottom plate 2.
The gear train is composed of 2, 13, and 14.

The first and third brake gears 12 and 14 constituting the gear train braking mechanism 9 are rotatably provided on studs 15 and 16 erected on the bracket 10, respectively. The gear 13 is the first-stage braking gear 12
A gear train composed of a three-stage gear train is rotatably supported at the other end of a link mechanism 17 rotatably provided on a stud 15 serving as a rotation center of the gear train, and by meshing these braking gears 12, 13, and 14. The braking mechanism 9 is constituted.

The first-stage braking gear 12 of the gear train braking mechanism 9 is engaged with a gear 11 provided on the driven shaft 3 so that the driven shaft 3
Is applied so that the descending speed of the bottom plate 2 when descending via the driven shaft 3 can be adjusted. In addition,
The bracket 10 is provided with a stopper 18 for regulating the swing range of the link mechanism 17. The stopper 18 is provided at a position where the engagement of the second-stage brake gear 13 and the third-stage brake gear 14 does not completely separate. The swing can be stopped.

According to the above embodiment, when the paper feed tray 1 of the paper supply device is pulled out of the image forming apparatus, the pin 8 is separated from the groove of the coupling, so that the driven shaft 3 is free to rotate. State. Therefore, the bottom plate 2 starts to descend due to the weight of itself and the paper placed on the bottom plate 2, and the wire 5 connected to the bottom plate 2 is pulled to rotate the hoisting pulley 4 and rotate the driven shaft 3. Let it.

The rotation of the driven shaft 3 is transmitted to a first-stage braking gear 12 of the gear train braking mechanism 9 via a gear 11 provided at one end of the driven shaft 3 to operate the gear train braking mechanism 9. When the first-stage brake gear 12 is rotated in the direction of arrow A in FIG. 4 by the lowering of the bottom plate 2, the second-stage brake gear 13 and the third-stage brake gear 14 rotate in the directions of arrow B and C, respectively. .

Further, by the rotation of the first-stage brake gear 12 in the direction of arrow A, the link mechanism 17 receives a swinging power in the direction of arrow S about the stud 15 and the second-stage brake gear 1.
3 is moved in a direction in which it is engaged with the third-stage brake gear 14. As a result, the second-stage brake gear 13 transmits the rotational force to the third-stage brake gear 14 and engages with the third-stage brake gear 14.

The third-stage brake gear 14 is driven to rotate by meshing with the second-stage brake gear 13. However, since the third-stage brake gear 14 has a sliding resistance against rotation between its shaft hole and the stud 16,
The arrow S is generated by the torque reaction due to the sliding resistance.
As a result, the second-stage brake gear 13 further meshes with the third-stage brake gear 14, and generates a braking load torque with respect to the rotation of the driven shaft 3 due to the lowering of the bottom plate 2.

The sliding resistance of the third-stage braking gear 14 engaged with the second-stage braking gear 13 is further increased, and the torque of the increased sliding resistance causes the second-stage braking gear 13 to move. Since the gear is further engaged with the third-stage brake gear 14, the sliding resistance is further increased.

The repetition of the engagement of the second-stage brake gear 13 with the third-stage brake gear 14 depends on the arrangement of the first-stage brake gear 12 and the third-stage brake gear 14 as described above. When the sliding resistance reaches a predetermined value, which is determined by the contact angle between the second-stage brake gear 13 and the third-stage brake gear 14 set by the length of the link mechanism 17, the constant value is obtained. The dynamic resistance applies a braking load torque when the bottom plate 2 descends during paper replenishment, and reduces the descending speed of the bottom plate 2 to prevent noise generation, deformation of the bottom plate 2 due to a sudden collision, and flapping of the paper. Then, the bottom plate 2 is stably lowered to the paper supply position.

When the bottom plate 2 rises, the rotation of each of the brake gears 12, 13, and 14 is reversed, and the link mechanism 17 is swung until it receives a force in the direction of arrow T and hits the stopper 18. As a result, the third-stage braking gear 14
Of the brake gear 13 of the second stage is reduced.
Since the above-described sliding resistance is hardly generated and the braking load torque for the rotation of the driven shaft 3 can be released, the bottom plate 2 can be smoothly raised to the sheet feeding position.

As described above, the gear train braking mechanism 9 having a simple structure in which a plurality of braking gears are combined has two functions of a brake and a one-way clutch. Since the bottom plate 2 can be lowered to the paper replenishing position by adjusting the descent speed of the bottom plate 2 while generating a torque and gradually increasing the braking load torque, the generation of noise due to a sudden collision and the It is possible to provide a paper supply device having a braking mechanism that is free from deformation, paper flapping, etc., is suitable for a large-capacity paper supply device, has a simple configuration, and can be manufactured at low cost.

FIG. 5 is a side view showing a schematic configuration of a main part of an image forming apparatus provided with a sheet supply device according to the embodiment of the present invention. In the figure, reference numeral 19 denotes an image forming apparatus provided with a paper supply device according to the embodiment of the present invention, and the image forming apparatus 19 includes therein paper feed trays 1, 1a, 1b, 1c, 1
d, 1e, and an image forming section 20 as an image forming means for forming an image on the paper supplied from each of the paper feed trays 1 to 1e. The paper feed tray 1 stores, for example, 1000 to 2000 sheets of frequently used A4 size paper, and is configured to be able to supply the paper to the image forming unit 20 in response to a large number of copies. The paper trays 1a to 1d store about 500 sheets of various types of paper of B5 to A3 size according to size and use, and are configured to be able to cope with paper size and use. The tray 1e stores about 500 sheets of A4 or A2 size paper and is configured to be able to cope with large-size copying.

These paper feed trays 1 to 1e are pulled out of the image forming apparatus 19 and replenish the paper when the number of papers is reduced due to the paper being used for copying and the paper needs to be replenished. At this time, the paper feed trays 1a to 1e pull out the paper feed trays 1a to 1e from the front of the image forming apparatus 19. In the sheet feed trays 1a to 1e, the remaining number of sheets is small, and the drawn sheet feed trays 1a to 1e
The bottom plate of e freely descends by its own weight. To supply paper to the paper feed tray 1, the front door of the image forming apparatus 19 is opened, the paper feed tray 1 is pulled out from inside the image forming apparatus 19, and paper is supplied. At this time, even if a large number of hundreds of sheets remain in the paper feed tray 1, the bottom plate 2 is controlled by the gear train braking mechanism 9 so that the lowering speed at the time of lowering is adjusted, and the bottom plate 2 is generated due to noise and sudden collision. 2 deformation,
Prevents flapping of the paper and stably lowers the bottom plate 2 to the paper supply position.

[0029]

As described above, according to the paper feeding apparatus of the present invention, the braking load torque that gradually increases on the driven shaft due to the increase in the sliding resistance caused by the engagement between the braking gears of the gear train braking mechanism. The bottom plate can be lowered while adjusting the lowering speed of the bottom plate, so that when lowering the bottom plate of the paper feed tray, the lowering speed is appropriately controlled to reduce the impact sound, deformation of the bottom plate, or paper. Can be prevented, and the bottom plate can be stabilized at a predetermined lowering position, so that the sheet supply operation can be easily performed.

Further, because of the gear train braking mechanism in which a plurality of braking gears are combined, the lowering speed of the bottom plate can be controlled more appropriately than the conventional braking mechanism using an expensive one-way damper mechanism or a centrifugal braking mechanism. It is an object of the present invention to provide a braking mechanism which is simple in configuration and can be manufactured at low cost.
Further, by the stopper that restricts the swing of the link mechanism when the bottom plate is raised, the swing of the link mechanism can be stopped at a position where the engagement of the braking gear is not completely separated.

Further, according to the image forming apparatus provided with the paper supply device according to the present invention, the gear train braking mechanism for adjusting the lowering speed of the bottom plate is provided in the large-capacity paper feed tray for frequently used papers. By feeding paper separately from the non-tall paper tray, it is possible to easily supply many sheets of paper without collision noise, deformation of the bottom plate, or flapping of paper when replenishing paper. It can be a forming device.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a configuration of a main part of a paper supply apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a configuration of a main part of the paper supply apparatus according to the embodiment of the present invention.

FIG. 3 is a plan view showing a configuration of a gear train braking mechanism of the paper supply device according to the embodiment of the present invention.

FIG. 4 is a side view showing a configuration of a gear train braking mechanism of the paper supply device according to the embodiment of the present invention.

FIG. 5 is a side view showing a schematic configuration of a main part of an image forming apparatus provided with a sheet supply device according to the embodiment of the present invention.

FIG. 6 is a configuration diagram illustrating an example of a braking mechanism of a conventional paper supply device.

FIG. 7 is a configuration diagram illustrating another example of a braking mechanism of a conventional paper supply device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Paper feed tray, 2 ... Bottom plate, 3 ... Driven shaft, 9 ... Gear train braking mechanism, 11 ... Gear, 12 ... 1st stage braking gear,
13: second-stage braking gear, 14: third-stage braking gear, 1
7 link mechanism, 19 image forming apparatus, 20 image forming unit

Claims (5)

[Claims] 1. A sheet feeding tray is pulled out of an image forming apparatus to lower a bottom plate, replenish sheets on the bottom plate, and then feed the sheet to the image forming apparatus by raising the bottom plate to a sheet feeding position. A driven shaft of the paper supply device, which is driven by being engaged with a drive shaft of the image forming apparatus, a gear provided on the driven shaft, and a gear provided with the driven gear; And a gear train braking mechanism comprising a plurality of braking gears for applying a braking load torque to the rotation of the driven shaft accompanying the descent. 2. The gear train braking mechanism according to claim 1, wherein at least three stages of braking gears are combined, and both braking gears are engaged between the second stage braking gear and the third stage braking gear only when the bottom plate is lowered. 2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is configured by incorporating means for increasing the number of sheets. 3. The engagement increasing means comprises a link mechanism that supports the second-stage brake gear and that can swing about the rotation center of the first-stage brake gear about an axis. 3. The paper supply device according to claim 2, wherein: 4. The swing regulating means of the link mechanism comprises a stopper which swings and contacts the link mechanism when the bottom plate is raised to the sheet feeding position. 3. The paper supply device according to 3. 5. A paper supply device which lowers the bottom plate by pulling out a paper supply tray, replenishes paper on the bottom plate, and raises the bottom plate to a paper supply position to enable paper supply. In the image forming apparatus, a driven shaft of a paper feeding device driven by being engaged with a drive shaft of the image forming device, a gear provided on the driven shaft, meshed with the gear, and associated with the lowering of the bottom plate A gear train braking mechanism comprising a plurality of braking gears for applying a braking load torque to the rotation of the driven shaft; and an image forming means for forming an image on a sheet fed by the sheet feeding device. An image forming apparatus provided with a sheet supply device.