JP3885517B2 - Paper feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device that feeds cut paper, such as a printer or a copying machine, and more particularly to a paper feeding device including a paper feed roll that feeds the cut paper and a separating member. It is.
[0002]
[Prior art]
In a paper feeding device that feeds the cut paper, such as a printer or a copier, the paper stacking tray that has been used conventionally swings around the fulcrum and lifts the leading edge of the paper to feed the paper. The structure is pressed against a paper roll. Accordingly, the angle of the paper when the paper surface hits the paper feed roll changes depending on the amount of paper loaded. As a result, the angle of the paper entering the separation roll or the separation pad that forms a pair with the paper feed roll and prevents the double feeding of the paper also changes. As the number of sheets stacked on the tray increases, this angle becomes steeper, and there is a problem that the sheet comes into contact with the separation roll or the separation pad and stops. In particular, when a separation roll is used, the angle hitting the paper feed roll is slightly increased, and the angle of entering the separation roll is greatly changed.
[0003]
In order to solve this problem, a device for elevating and lowering a paper stacking tray in an elevator type as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-1117138 has been developed, but it has a complicated mechanism and a large space. The cost was high. For example, as disclosed in Japanese Patent Application Laid-Open No. 11-11690, a technique has been proposed in which the above-described drawbacks are reduced by using a spring and a link. However, this technique still requires a large space, for example, a manual paper feeder. It is not suitable for a device that cannot take up a large space.
[0004]
[Problems to be solved by the invention]
The present invention has been developed in order to solve the above problems, and has as its object to keep the angle at which paper enters the separation roll or a separation pad always substantially constant, smooth feeding the securing of the paper it is to Rukoto. Also, eliminating the breakage of the paper, and an object thereof is to provide a technique for stabilizing the sheet feeding. At the same time, the sheet is prevented from being fed and fed by the frictional force of the sheet.
[0006]
[Means for Solving the Problems]
The present invention provides a sheet feeding device that includes a sheet feeding roll and a separating member and feeds a cut sheet, and includes a bottom plate that pushes up the sheet and makes the upper surface of the sheet contact the sheet feeding roll. The support means for supporting the paper fixedly arranged between the bottom plate at the lowest position and the paper stacking tray is provided on the lower side of the bottom plate of the bottom plate that moves up and down. It is characterized by.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a main part of a sheet feeding device 10 according to the embodiment, and FIG. 2 is a plan view thereof. The half-moon-shaped paper feed roll 20 is attached to a shaft 21, is fixed to the shaft 21 by a rotation stopper, and is configured to rotate integrally with the shaft 21. Auxiliary rollers 22 are disposed on the shafts on both sides of the paper feed roll 20, and the auxiliary rollers 22 rotate freely with respect to the shaft 21. Both ends of the shaft 21 are supported on the wall of the main body via conductive bearings 23. A side view of the bearing 23 is shown in FIG. A ring groove 24 is formed in the bearing 23, and an upper end of a spring 33 that pulls up the bottom plate is locked in the ring groove. Further, a cam 35 that moves the bottom plate 30 up and down is attached to the shaft 21. The cam 35 is disposed on the shaft 21 at a position inside the bearing 23. A front view of the cam 35 is shown in FIG. 7A, and a CC arrow view is shown in FIG. 7B. The cam 35 has a hole 35b fitted into the shaft 21, and the cam edge 35a pushes down the bottom plate every rotation of the shaft.
[0008]
A guide pin 31 for guiding the bottom plate 30 is provided below the paper feed roll 20, and the guide pin 31 is disposed so that the center line passes near the central axis of the paper feed roll 20. A cylindrical member 32 is attached to both ends of the bottom plate 30, and a guide pin 31 is inserted into a hole of the cylindrical member 32. A spring 33 for pulling up the bottom plate 30 is attached. One end of the spring 33 is coupled to the cylindrical member 32, and the other end is coupled to the ring groove 24 of the bearing 23 as described above. The cylindrical member 32 attached to the bottom plate 30 is made of a material excellent in slidability and conductivity. The bottom plate 30 is grounded via the bearing 23, the spring 33, and the shaft 21. The shaft 21 is in contact with a leaf spring and is connected to the ground of the power source.
[0009]
A paper stacking tray 40 is provided on the upstream side in the transport direction of the paper feed roll 20, and the upper surface thereof is located at a substantially intermediate height between the uppermost position and the lowermost position of the bottom plate 30. On the upstream side of the guide pin 31 in the conveying direction, a thin sheet-like paper support member 41 is erected in parallel with the center line of the guide pin 31. The upper end of the sheet-like sheet support member 41 is disposed at a position that forms a curve that smoothly connects the steps between the uppermost surface of the bottom plate 30 and the upper surface of the sheet stacking tray 40. The paper support member 41 has a smooth profile and supports paper between the paper stacking tray 40 and the bottom plate 30. The bottom plate 30 has a hole 34 through which the paper support member 41 passes vertically, so that the bottom plate 30 does not interfere with the paper support member 41 even when the bottom plate 30 moves up and down.
[0010]
3 is a structural diagram showing details of the shaft 21 of the paper feed roll 20, and FIGS. 4 and 5 are views taken along arrows AA and BB in FIG. 3, respectively. On the shaft 21 of the paper feed roll 20, a notched gear 25 that rotates integrally with the shaft 21 and a cylindrical member 26 having a protrusion are provided. A side view of the notch gear 25 is shown in FIG. Further, FIG. 9A shows a side view of the cylindrical member 26 having protrusions, and FIG. 9B shows a longitudinal sectional view thereof. The cylindrical member 26 having a protrusion is provided with a protrusion 26 a on the outer periphery of the cylinder, and is provided with a shaft hole 26 b and a locking portion 26 c for locking with a spring 29. A solenoid 27 is provided in the vicinity of the cylindrical member 26 having the protrusion 26a. The claw of the claw lever 28 driven by the solenoid 27 hits the protrusion 26a on the outer periphery of the cylindrical member 26. It is designed to prevent rotation in the direction. FIG. 10 is an explanatory view showing the solenoid 27 and the claw lever 28. When the solenoid 27 is not in the activated state, the spring 28b pulls the claw lever 28, and the claw 28a at the tip is in contact with the protrusion 26a shown in FIG.
[0011]
As shown in FIG. 5, the cylindrical member 26 with the protrusion is biased by a spring 29 so that the shaft 21 rotates in the paper feeding direction. A drive gear 36 is provided in the vicinity of the notch gear 25, and the notch gear 25 is not engaged with the drive gear 36 by the notch in the standby state.
[0012]
As shown in FIG. 1, in the standby state, the bottom plate 30 is lowered to the lowest position by the cam 35, and the upper surface of the paper stacking tray 40 is above the upper surface of the bottom plate 30. If the top surface of the paper stacking tray 40 is the same as the re-lowering position of the bottom plate 30, the paper is bent when the bottom plate 30 is raised, and the leading edge of the paper is separated from the paper feed roll to cause misfeeding. . When the upper surface of the paper stacking tray 40 is at the uppermost position of the bottom plate 30, the front end of the paper hits a component on the downstream side while the bottom plate 30 is moving up. If the position of the upper surface of the sheet stacking tray is set at an intermediate position for raising and lowering the bottom plate 30, the above-described problems can be prevented. A paper support member 41 is disposed at a position that smoothly connects the step between the two surfaces of the upper surface of the paper stacking tray 40 and the upper surface of the bottom plate 30 that moves up and down, and above the bottom plate 30 and the paper stacking tray 40. The paper loaded on the paper will not be forcibly folded. In the standby state, the paper is not in contact with the paper feed roll 20 due to the cutout portion of the half-moon shaped paper feed roll 20. When the solenoid 27 is actuated in response to the paper feed start signal, the contact between the projection 26a of the cylindrical member 26 and the tip 28a of the claw lever 28 is released, and the cylindrical member 26 is rotated by the spring 29 to be cut off. The notch gear 25 is driven by meshing with the drive gear 36, and the paper feed roll 20 rotates. At this time, the cam 35 on the coaxial 21 also rotates, and the bottom plate 30 pushed down by the cam 35 rises along the guide pin 31 by the force of the spring 33. The bottom plate 30 presses the paper loaded thereon against the paper feed roll 20. Next, the sheet is conveyed to the downstream side by the sheet feeding roll 20 that has started to rotate, and abuts against the separation roll 50. Since the bottom plate 30 moves up and down in parallel along the guide pins 31, the paper entry angle at this time is a constant angle regardless of the thickness of the paper stack, when the number of stacked paper is small or large. . Accordingly, the sheet is conveyed while sliding on the surface of the separation roll 50, and does not stop by hitting the separation roll 50. The sheet bundle is separated at the place where the sheet feed roll 20 and the separation roll 50 are in contact, and only the uppermost sheet is conveyed downstream. When the paper feed roll 20 rotates once, the paper feed roll 20 is separated from the separation roll 50. However, since the auxiliary roller 22 is in contact with the separation roll 50, the second sheet is not put on the uppermost sheet and does not advance beyond the separation roll 50.
[0013]
While the paper is transported, static electricity accumulates and adversely affects the machine, such as radio noise. However, since the cylindrical member 26 is conductive, the charges accumulated on the bottom plate 30 and the like are absorbed by the spring 33 and the shaft of the paper feed roll 20. You can escape via 21. In the above embodiment, the spring 33 that urges the bottom plate 30 is a tension spring. However, it may be replaced with a compression spring and a member that receives the bottom of the spring may be grounded. In that case, the bearing 23 may not be a material having excellent conductivity.
[0014]
【The invention's effect】
According to the present invention, the guide portion that guides the portion near the tip of the bottom plate that pushes up the paper and abuts the upper surface of the paper to the paper feed roll so as to be movable up and down substantially parallel to the upper surface of the bottom plate is formed. With this structure, the angle at which the paper enters the separating member can be made almost constant regardless of the paper stacking amount. As a result, when the separation member is a roll, the diameter of the separation roll can be reduced. Also, the amount of paper loaded can be increased. On the other hand, the size of the machine can be reduced.
[0015]
In addition, since a cam that moves the vicinity of the tip of the bottom plate in parallel up and down is attached to the rotating shaft of the paper feed roll, it is possible to realize cost saving and space saving with a simple structure. Also, since the guide direction of the pin that guides the parallel movement of the portion near the tip of the bottom plate is arranged at a position that passes the vicinity of the rotation axis of the paper feed roll, a spring that biases the bottom plate in the parallel movement direction is provided. The bottom plate can move smoothly, so that the paper does not hit the paper feed roll and does not misfeed. Further, the mechanism is a simple structure, and cost saving and space saving can be realized.
[0016]
Further, since the members at both ends of the spring are made of a conductive material, static electricity generated by friction with the paper can be released, and adverse effects on the image can be avoided.
[0017]
In addition, since the upper surface of the paper stacking tray is a paper feed roll rather than the lowermost upper surface of the bottom plate, movement of the paper can be reduced when the bottom plate rises at the start of paper feeding. Accordingly, the sheet is less likely to be shifted back and forth, and the sheet feeding is stabilized. In addition, since a paper support member that smoothly connects the step between the top surface of the bottom plate and the top surface of the paper stacking tray is provided between the bottom plate and the paper stacking tray, the paper is connected to the seam between the bottom plate and the paper stacking tray. Stacks without forcibly breaking at the part and feeds stably. In particular, when the paper is loaded and left under high humidity for a long time, if this paper support member is not provided, the paper will be broken at the seam of the tray, causing a problem of misfeeding. This does not happen in the present invention.
[Brief description of the drawings]
FIG. 1 is a side view illustrating a main part of a paper feeding device.
FIG. 2 is a plan view of a paper feeding device.
FIG. 3 is a structural diagram showing details of a paper feed roll shaft.
4 is a view taken in the direction of arrows AA in FIG. 3;
5 is a BB arrow view of FIG. 3;
FIG. 6 is a side view of the bearing.
FIG. 7 is a front view and a CC arrow view of the cam.
FIG. 8 is a side view of a notch gear.
FIG. 9 is a side view and a longitudinal section of a cylindrical member having a protrusion.
FIG. 10 is an explanatory diagram showing the action of a solenoid.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Paper feeder 20 Paper feed roll 21 Shaft 22 Roller 23 Bearing 24 Groove (spring latching part)
25 Notch gear 26 Cylindrical member 27 Solenoid 28 Claw lever 29 Spring 30 Bottom plate 31 Guide pin 32 Cylindrical member 33 Spring 34 Hole 35 Cam 36 Drive gear 40 Paper stacking tray 41 Paper support member 50 Separating roll 60 Paper

Claims (1)

In a paper feeding device that includes a paper feed roll and a separating member and feeds the cut paper, a bottom plate that pushes up the paper and makes the upper surface of the paper contact the paper feed roll is provided, and the upper surface of the paper stacking tray moves up and down. A support means for supporting a sheet fixedly disposed between the bottom plate at the lowermost position and the paper stacking tray is provided on the paper feed roll side from the uppermost surface of the lowermost position of the bottom plate. Paper feeder.

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