JP3637240B2 - Paper feeder for image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feeding device of an image forming apparatus such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
2. Description of the Related Art In many paper feeding apparatuses such as copying machines, printers, and facsimile machines, a main body having a paper feeding tray set so as to be able to be pulled out in a direction substantially perpendicular to the paper feeding direction is adopted. In this type of paper feeder, when the paper feed tray is set in the apparatus main body, it is necessary to push up the movable bottom plate to a position where the uppermost sheet of the paper bundle contacts the paper feed roller. As a method for pushing up the movable bottom plate, a method using an electric motor as a drive source is known as described in JP-A-7-267385. Further, a pressurization method using a pressurization spring as a drive source for pushing up the movable bottom plate is also known.
[0003]
By the way, the pressing force of the paper feeding roller to the paper is an important characteristic value related to the paper feeding performance, and it is desirable that the pressure is constant regardless of the paper type and paper size. However, since the area on the movable bottom plate differs depending on the size of the paper, it is extremely difficult to keep the pressure of the paper feeding roller on the paper constant with one spring.
[0004]
In order to alleviate such a problem, there has been proposed a method in which a spring is used in conjunction with the attachment / detachment of the paper feed tray.
[Problems to be solved by the invention]
[0005]
However, in the paper feeding device that raises the bottom plate by the above-described electric motor, it is directly raised by the driving force of the motor, so it is difficult to adjust the pressing force, and the pressing force of the feeding roller for each paper size is made constant. Could not be corrected.
[0006]
In addition, the latter is inexpensive, but the operability is poor because the bottom plate must be pushed down by hand each time the paper feed tray is pulled out. There was a problem that was narrow.
[0007]
The present invention eliminates the above-described conventional problems, and can push the sheet feeding rotating body to a position where it abuts against the sheet with a pressurizing force suitable for the sheet size. It is an object of the present invention to provide a paper feeding device for an image forming apparatus.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention feeds a paper feed tray set in the image forming apparatus main body so that it can be pulled out in a direction substantially perpendicular to the paper feed direction, and papers stacked on the paper feed tray. In a paper feeding device of an image forming apparatus having a paper feeding means and a bottom plate push-up mechanism that pushes up a movable bottom plate of the paper feed tray through a push-up member, the bottom plate push-up mechanism sets the paper feed tray when the paper feed tray is set. A push-up transmission means connected to the push-up member and transmitting a push-up force to the push-up member, a turning member that is turned by a driving device that is driven when the paper feed tray is set, the turning member and the push-up Main urging means for linking the transmission means and urging the push-up force according to the rotation of the rotation member, and correction for different rotation amounts according to the size of the paper loaded on the paper feed tray A moving member, a correction biasing member that connects the correction rotation member and the push-up transmission unit, and biases a push-up force according to the rotation of the correction rotation member; and a lock unit that locks the push-up transmission unit The push-up transmission member transmits the push-up force to the push-up member after the lock means is unlocked by the action of the main biasing means.
[0009]
According to the present invention, the push-up transmission member includes a transmission shaft that can be coupled to the push-up member, a first pressure member that is rotatably attached to the transmission shaft, and a first shaft that is fixed to the transmission shaft. The first pressure member is biased by the main biasing means, the second pressure member is biased by the correction biasing means, and the first pressure member is It is effective to transmit the rotational force of the main biasing means to the transmission shaft through the second pressure member after the lock means is unlocked.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory plan view showing an example of a sheet feeding device according to the present invention.
[0011]
In FIG. 1, reference numeral 1 denotes a paper feed tray. The paper feed tray 1 is moved in a direction perpendicular to the paper feed direction with respect to an image forming apparatus main body such as a copying machine, a printer, or a facsimile machine indicated by an arrow A. It is configured to be pulled out from the set position and attached to the set position. As shown in FIG. 2, this paper feeding device pushes up the movable bottom plate 5 to bring a paper into contact with a paper feeding roller 2 as a paper feeding rotating body, and feeds paper from the uppermost paper by the rotation of the paper feeding roller 2. It is. The paper feeding roller 2 may be a half-moon shape with a part missing.
[0012]
In the paper feed tray 1, a side fence 3 and an end fence 4 are provided as paper regulating members that can be adjusted and moved according to the size of the paper to be loaded. Further, the paper feed tray 1 is provided with a movable bottom plate 5 at a position where paper is placed, a push-up member 6 for pushing up the movable bottom plate 5, and a correction projection 7 provided on the side fence 3. The member 6 is fixed to one end of the push-up shaft 8, and a meshing protrusion 9 is provided on the other end of the push-up shaft 8 on the image forming apparatus main body side.
[0013]
On the other hand, a bottom plate push-up mechanism for pushing up the movable bottom plate 5 via the push-up member 6 is provided on the image forming apparatus main body side. The bottom plate push-up mechanism of the present embodiment is connected to the push-up shaft 8 when the paper feed tray 1 is set, and when the paper feed tray 1 is set, the push-up transmission means 10 that transmits the push-up force to the push-up member 6. A rotation lever 24 as a rotation member rotated by a motor 21 as a driving device to be driven, and the rotation lever 24 and the push-up transmission means 10 are connected to each other, and a push-up force according to the rotation of the turn lever 24 And a tension spring 30 as main urging means for urging.
[0014]
As shown in FIG. 6, the push-up transmission means 10 has a coupling 11 that meshes with the meshing protrusion 9 of the push-up shaft 8 when the paper feed tray 1 is set, and the coupling 11 is attached to the main body frame 19. It is provided at one end of a transmission shaft 12 that is rotatably mounted. As shown in FIGS. 1 and 3, a first pressure arm 13 is rotatably attached to the transmission shaft 12, and a second pressure arm 43 and a lock piece 14 described later are fixed to the transmission shaft 12. Yes. As shown in FIG. 4, the lock piece 14 locks the transmission shaft 12 by locking a stopper member 16 that is rotatably mounted on the shaft 15. The stopper member 16 is provided with a roller 17 that can contact the first pressure arm 13, and the stopper member 16 has a rotating force in a direction in which the stopper member 16 always contacts the lock piece 14 around the shaft 15 as a spring. 18 is energized. The lock piece 14 and the stopper member 16 constitute the lock means of this embodiment.
[0015]
The motor 21 is arranged at a fixed position, and a coupling 23 is provided at the tip of the drive shaft 22. At a position facing the coupling 23, the moving shaft 25 is disposed so that one end side thereof is opposed, and a meshing protrusion 26 that meshes with the coupling 23 is provided at one end of the moving shaft 25. The moving shaft 25 is attached to the main body frame 19 so as to be movable in the thrust direction. When the paper feed tray 1 is set, the other end is pushed and the meshing protrusion 26 is coupled to the coupling 23. Is engaged. The springs 27 and 28 are for ensuring the engagement between the engagement protrusion 26 and the coupling 23, and the spring 27 constantly urges the moving shaft 25 in the direction close to the sheet feed tray 1, The spring 28 always urges the drive shaft 22 in a direction close to the moving shaft 25. Reference numeral 29 denotes a holder for receiving the spring 27. One end side of the rotation lever 24 is fixed to the moving shaft 25, and the other end side of the rotation lever 24 is connected to the first pressure arm 13 via a tension spring 30.
[0016]
Further, as shown in FIG. 1, the sheet feeding device is provided with a correction pressurizing unit 40 that adjusts the bottom plate pushing force according to the sheet size set in the sheet feeding tray 1. The correction pressure unit 40 includes a correction pressure lever 41 provided on the apparatus main body side so as to be rotatable around a pin 42. One end of a correction tension spring 43 is locked to the correction pressure lever 41, and the other end of the correction tension spring 43 is locked to a second pressure arm 44 fixed to the transmission shaft 12. The tension spring 43 urges the first pressure arm 13 in the same direction as the tension spring 30.
[0017]
The first pressure arm 13 is provided with a roller 13 a, and the roller 13 a is loosely fitted to a receiving portion 44 a formed on the second pressure arm 44. When the paper feed tray 1 is set, the rotational force of the first pressure arm 13 is transmitted to the second pressure arm 44 via the roller 13a and the receiving portion 44a to rotate the transmission shaft 12. Yes.
[0018]
1, 3, and 6 show an initial state in which the paper feed tray 1 is not set in the apparatus main body. In this state, the first pressurizing arm 13 and the first pressure arm 13 are the same. The two pressure arms 44 are held at the positions shown by holding means not shown. As an example of the holding means, the transmission shaft 12 is constituted by a torsion spring that urges the rotational force in the clockwise direction of FIG. 3 and a stopper that stops at the position. The stopper 16 in the initial state is also held at the position shown in the figure by the spring 18.
[0019]
When the paper P is loaded on the paper feed tray 1 and set in the image forming apparatus main body from the direction of arrow A in FIG. 1, the meshing protrusion 9 of the push-up shaft 7 is meshed with the coupling 11 and the moving shaft 25. Is pushed by the side plate of the paper feed tray 1 and moves in the thrust direction, and the meshing protrusion 26 is meshed with the coupling 23. When the paper feed tray 1 is set, a sensor (not shown) detects it, and the motor 21 starts to be driven by that signal. When the motor 21 starts driving, the moving shaft 25 rotates through the driving shaft 22, the coupling 23, and the meshing protrusion 26, and the rotating lever 24 is rotated counterclockwise in FIG. As shown in FIGS. 4 and 5, this rotation is stopped at a position where the rotation lever 24 turns on the photo interrupter 31 as the detecting means, that is, the driving of the motor 21 is stopped by the ON signal of the photo interrupter 31. .
[0020]
Further, when the paper feed tray 1 is set in the main body of the image forming apparatus, if the loaded paper is large, the correction projection 7 pushes the correction pressure lever 41 and the correction pressure lever 41 rotates around the shaft 42. Move. By this rotation, the correction tension spring 43 is charged, and rotational force is urged to the second pressure arm 44. Then, the turning force to the second pressure arm 44 may be urged before the rotation of the rotation lever 24 by the motor 21 is transmitted to the pressure arm 13, but at this time, as shown in FIG. Furthermore, since the stopper member 16 is locked to the lock piece 14, the second pressure arm 44 does not rotate.
[0021]
When the rotation lever 24 is rotated, the first pressure arm 13 is also rotated counterclockwise against the action of the holding means via the tension spring 30, and the rotation reaches a predetermined angle. Then, the roller 17 of the stopper member 16 is pushed up. As a result, as shown in FIG. 8, the stopper member 16 is released from the lock piece 14 and the lock is released. When the rotation further proceeds, the roller 13 a of the first pressure arm 13 hits the receiving portion 44 a of the second pressure arm 44, and the first pressure arm 13 acts by the tension spring 30 to cause the second pressure arm 44. Is turned counterclockwise to a state shown in FIG. At this time, since the second pressure arm 44 is fixed to the transmission shaft 12, the second pressure arm 44 is transmitted to the push-up member 6 through the transmission shaft 12, the coupling 11, the meshing protrusion 9 and the push-up shaft 8, and the movable bottom plate 5 is moved upward. And is stopped at a position where the sheet feeding tray 1 side and the action of the tension spring 30 are balanced.
[0022]
When the paper feed tray 1 is set in the main body of the image forming apparatus, the correction protrusion 7 presses the correction pressure lever 41 when the paper is large, and when the paper is small, the correction protrusion 7 Does not reach the correction pressure lever 41, the correction pressure lever 41 does not rotate.
[0023]
Thus, when the paper feed tray 1 is set, the movable bottom plate 5 is automatically raised and the paper can be fed. At this time, since the movable bottom plate 5 is raised by driving the motor 21, the operator does not need a large setting force when pushing the paper feed tray 1, and the operability is good. Moreover, since the transmission shaft 12 is unlocked by driving the motor 21, the transmission shaft 12 is rotated by the correction tension spring 43, and the main tension spring 30 is bent by the action of the correction tension spring 43. Can surely be prevented. If the tension spring 30 bends, the spring may sandwich the surrounding members and the like, which may cause unexpected problems such as breakage of parts, and the present invention prevents such problems.
[0024]
【The invention's effect】
According to the configuration of the first and second aspects, it is possible to improve the operability by reducing the setting force when the paper feed tray is mounted, and to reliably prevent the main biasing means from being bent. .
[Brief description of the drawings]
FIG. 1 is an explanatory plan view illustrating an example of a sheet feeding device according to the present invention and a state when a sheet feeding tray is not set.
FIG. 2 is an explanatory diagram showing a sheet feeding roller portion of the sheet feeding device.
FIG. 3 is an explanatory side view illustrating a rotation lever in the sheet feeding device in the state of FIG. 1;
4 is an explanatory plan view showing a state when a paper feed tray is set in the paper feed device of FIG. 1; FIG.
FIG. 5 is an explanatory side view showing a rotation lever in the sheet feeding device in the state of FIG. 4;
FIG. 6 is an explanatory diagram showing push-up force transmission means when a paper feed tray is not set.
FIG. 7 is an explanatory diagram showing a state of a push-up force transmission means at the time of locking.
FIG. 8 is an explanatory diagram showing a state of the push-up force transmitting means immediately after the lock is released.
FIG. 9 is an explanatory diagram showing a state of the pushing force transmission means when the movable bottom plate is pushed up.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paper feed tray 2 Paper feed roller 3 Side fence 4 End fence 5 Movable bottom plate 6 Push-up member 10 Push-up force transmission means 11 Coupling 12 Transmission shaft 13 Pressure arm 14 Lock piece 16 Stopper member 21 Motor 24 Rotating lever 30 Tension spring 40 Pressure correction mechanism 43 Correction tension spring 44 Correction pressure arm

Claims (2)

A paper feed tray that is set in the image forming apparatus main body so that it can be pulled out in a direction substantially perpendicular to the paper feed direction, a paper feed unit that feeds the paper stacked on the paper feed tray, and a movable part of the paper feed tray. In a sheet feeding device of an image forming apparatus having a bottom plate push-up mechanism that pushes up a bottom plate through a push-up member,
The bottom plate push-up mechanism is connected to the push-up member when the paper feed tray is set, and a push-up transmission means for transmitting a push-up force to the push-up member, and a drive device that is driven when the paper feed tray is set. A rotating member that is rotated, a main urging unit that connects the rotating member and the push-up transmission unit, and urges a push-up force according to the rotation of the turning member, and a stacking unit on the paper feed tray A correction rotation member having a different rotation amount according to the sheet size, a correction rotation member that connects the correction rotation member and the push-up transmission means, and that biases a push-up force according to the rotation of the correction rotation member. And a lock means for locking the push-up transmission means. The push-up transmission member applies a push-up force to the push-up member after the lock means is unlocked by the action of the main biasing means. Sheet feeding apparatus characterized by reach.   The push-up transmission member includes a transmission shaft that can be coupled to the push-up member, a first pressure member that is rotatably attached to the transmission shaft, and a second pressure member that is fixed to the transmission shaft. The first pressure member is biased by the main biasing means, the second pressure member is biased by the correction biasing means, and the first pressure member unlocks the locking means. 2. The sheet feeding device according to claim 1, wherein after the first pressure member, the rotational force of the main urging unit is transmitted to the transmission shaft via the second pressure member.

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