JPH07102908B2 - Automatic paper feeder - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for automatically feeding stacked sheets one by one, and a sheet feeding roller for feeding sheets by friction drive. The present invention relates to an automatic sheet feeder including a resistance member that separates sheets by a friction load or a locking load.

<< Prior Art >> A feed roller is brought into contact with the upper surface of stacked sheets to rotate it so as to give a feeding force to the upper surface of laminated sheets, and a plurality of sheets to be delivered by the sheet feeding roller are obliquely placed on the lower surface of the sheet. There is known an automatic paper feeder having a structure in which a separating pad arranged so as to collide with a sheet or a locking claw that locks the leading end of the sheet is used to separate and pass only one sheet. FIG. 5 shows an example of a conventional separating pad type automatic paper feeder. Reference numeral 1 is a paper tray supported by a guide (not shown) so that the paper tray can be lifted and lowered. 2 is a sheet stacked on the paper tray. Is a guide plate for guiding the leading edge of the stacked sheets 2, 4 is a support arm pivotally attached to an immovable member by a support shaft 5, and 6 is a paper feed which is pivotally attached to the tip of the support arm and is driven in the direction of the arrow in the figure. Rollers, 7 are level detection sensors that detect the paper feed level by the swing angle of the support arm 4, 8 are stoppers that regulate the downward movement angle of the support arm 4, and 9 is a sheet of paper that is about to be sent out by the paper feed roller 6. A separation pad for imparting frictional resistance to the tip for separation, 10 is a paper detection sensor for detecting a paper that has passed over the separation pad, 11
Is a rack fixed to the paper tray 1, and 12 is a pulse motor having a pinion 13 that meshes with the rack.

In the conventional apparatus, the paper is fed at a constant level regardless of the thickness of the stacked paper 2, and the contact position A between the paper feed roller 6 and the upper surface of the stacked paper 2 and the front end of the paper to be fed are separated. The collision position B with the pad 9 is constant, and the interval L between the contact position A and the collision position B is also constant. Further, a structure is often used in which the support arm 4 is urged downward by a spring to obtain a desired contact force with the paper 2. In such a structure, the upper surface of the paper 2 and the paper feed roller 6 are also used. The contact force with and is constant.

<< Problems to be Solved by the Invention >> In an automatic paper feeding device, particularly an automatic paper feeding device attached to an office computer, a printer or a reader of a personal computer, there is a demand for one device to automatically feed all types of paper. Extremely strong. For example, even one sheet of paper is required to be able to automatically feed a wide variety of papers from thin paper equivalent to 45 kg / ream to thick paper equivalent to 220 kg / ream without trouble.

However, the paper has different rigidity (strength of the waist) depending on its thickness. For example, since thick paper has a large bending strength, it cannot be smoothly bent when it collides with the separation pad 9, and it bites into the surface of the pad, and a picking error, that is, a problem that the paper is not fed out easily occurs. The pick-up error can be avoided by increasing the contact force between the paper feed roller 6 and the paper or separating the contact position from the separation pad 9. However, in this case, double feed is likely to occur when a thin paper is fed. The problem arises that the range of sheet thickness that can be automatically fed is limited. There is also a method of solving the above problem by adjusting the contact force between the sheet feeding roller 6 and the stacked sheets 2 according to the type of sheet, but since the device must be adjusted every time the sheet thickness changes, the operation and Control becomes troublesome.

Therefore, an object of the present invention is to obtain an automatic paper feeder having a simple structure and capable of handling paper in a wider thickness range without requiring an adjusting operation.

<< Means for Solving the Problem >> In the present invention, the distance L between the contact position A and the collision position B is L.
The above problem is solved by adopting a control means for automatically setting the interval by making the variable.

That is, in the automatic sheet feeding device of the present invention, the upper surface of the stacked sheets 2 and the sheet feeding roller 6 are moved along with the rising of the sheet table 1 or the lowering of the supporting member 5 of the sheet feeding roller 6 when performing the sheet feeding operation.
In order to detect the level at which the abutting position A with respect to and / or the collision position B between the resistance members 9 and 9a and the leading end of the paper are moved in the direction away from each other and the rotation command is first given to the paper feed roller 6. The level detection sensor 7 is provided to give the first rotation command to the paper feed roller 6 at the level, and when the detection signal is not output from the paper detection sensor 10 by this rotation, the paper table 1 is raised by a predetermined amount or supported. A control means for lowering the member 5 by a predetermined amount and rotating the paper feed roller 6 again is adopted.

<< Operation >> In the above structure, the level at which the paper feed roller 6 is first rotated is set based on the feeding of thin paper, and the thin paper is delivered at the first feeding level. When the paper is thick paper, at the first paper feed level set for thin paper, strong resistance from the resistance members 9 and 9a is caused by the stiffness of the paper, so that the paper feed roller 6 slides on the upper surface of the paper. Is not fed. If the paper is not fed, the detection signal is not output from the paper detection sensor 10, so that the paper tray 1 is raised by a predetermined amount or the support member 5 is lowered by a predetermined amount. By this operation, the contact position A of the sheet feeding roller 6 and the collision position B of the resistance members 9 and 9a.
The sheet feeding condition changes in a direction suitable for feeding thick paper, such as the distance L between the sheet and the sheet becoming wider and the sheet easily bent. Then, the paper feeding roller 6 is rotated again to try paper feeding. If the paper is still not fed out, the above-mentioned operation is further repeated to change the paper feed condition until the paper is fed out. That is, in the apparatus of the present invention, the contact position A of the sheet feeding roller 6 and the collision position B of the resistance members 9 and 9a depend on the sheet thickness.
If the distance L between the paper feed roller 6 and the paper feed roller 6 is urged downward, the pushing force between the paper feed roller 6 and the paper is automatically set to prevent picking mistakes and double feed. It is possible to automatically feed a wide variety of papers having different thicknesses without causing them.

<< Embodiment >> FIGS. 1 to 3 show an embodiment of the present invention, in which the present invention is applied to a separation pad type automatic paper feeder having a structure similar to that of FIG. It is a thing.

2 and 3, the members described in FIG. 5 are denoted by the same reference numerals as those in FIG. 5, and the parts different from the structure in FIG. 5 are the tip shape of the support arm 4 and the level detection sensor. There are only 7 mounting structures. The tip of the support arm 4 has an arc surface centered on the support shaft 5, and the level detection sensor 7 is brought into contact with the arc surface to operate. With this structure, even if the support arm 4 further moves after the level detection sensor 7 detects the support arm 4, the detection signal can be maintained without damaging the sensor 7. Further, in this structure, the sensor 7 is turned off when the support arm 4 swings largely and pivots above the sensor 7, and this off signal is used as an abnormal stop signal in the control of FIG. In the standby state, the paper tray 1 is in the lowered position, the lowering of the support arm 4 is stopped by the stopper 8, and the upper surface of the stacked paper 2 and the peripheral surface of the paper feed roller 6 are slightly separated.

Now, in FIG. 1, when a paper feed command is given from the main body device, a raising command is given to the paper tray 1, the upper surface of the stacked paper 2 comes into contact with the paper feed roller 6 and pushes up the support arm 4,
The paper tray 1 rises until the level detection sensor 7 turns on,
The upper surface of the stacked sheets 2 is set to the first sheet feeding level. Then, in step 21, the paper feed roller 6 is rotated immediately in step 22 after giving a timer start command to the timer. The state at this time is shown in FIG. 2, and the position B where the leading edge of the sheet to be sent out collides with the separation pad 9 is from the contact position A of the sheet feeding roller 6 to the upper surface of the stacked sheets 2. The distance L ₁ is separated.

If the paper detection sensor 10 detects the paper before the end of the counting of the timer is detected in step 24, it is considered that the paper has been sent out normally, and the paper feed roller 6 is set at the time of subsequent transfer of the sent out paper. In order to avoid a feeding load, the paper tray 1 is lowered to separate the paper feed roller 6 from the paper surface, and the next step such as a printing operation is started.

When the timer counts up before the paper feed is detected in step 23, it is considered that the paper is not fed by the separation pad 9 because the paper is stiff, and the paper tray 1 is placed in step 25. Increase by a fixed amount. This operation is performed by giving the pulse motor 12 a predetermined amount of drive pulse in the upward direction. Then, the control returns from step 26 to before step 21, restarts the timing of the timer, and rotates the paper feed roller 6 to try again the paper feed. When the paper tray 1 is further raised from the initial paper feed level, as shown in FIG. 3, the leading edge of the paper to be sent out collides at a higher position of the separation pad 9, and the separation pad 9 Since the paper feed direction is inclined so as to be high, the collision position B of the paper on the separation pad is separated from the contact position A of the paper feed roller on the paper,
Due to the support structure of the paper feed roller 6, the contact position A also moves slightly in the separating direction, and the distance L ₂ between the two A and B becomes wider than the initial distance L ₁ . Therefore, the sheet to be sent out is more likely to be bent between both A and B, and is more likely to pass through the thick sheet.

Then, the operation from step 21 to step 26 is repeated until the sheet detection sensor 10 detects the passing sheet,
When the distance L becomes an amount suitable for the paper thickness, the paper is separated and sent out, and the distance L is not excessively wide with respect to the paper thickness, so that double feeding does not occur.

When the level detection sensor 7 is disengaged from the tip of the support arm 4 and turned off again due to the repeated movement of the paper tray 1, it is considered that the paper is not fed due to some abnormality,
In step 27, the device is stopped abnormally.

Although the above description is for the separation pad type device, even in the case of the locking claw type automatic paper feeding device, the support arm 4 is fed back by the upward movement of the paper table 1 as shown in FIG. By swinging in the direction, the contact position A of the sheet feeding roller 6 can be separated from the collision position B of the locking claw 9a to widen the distance L between the two A and B. As the distance L becomes wider, the paper easily bends within the distance, and the bending makes it easier to disengage from the locking claw 9a. Therefore, it is possible to automatically feed a paper having a different thickness by the same control as described above.

Further, although the above embodiment has a structure in which the interval L is widened by raising the paper table 1, the paper table 1 is fed by the structure shown in FIGS. 2 and 3 and the structure shown in FIG. Since the above-described operation is achieved by moving the roller relatively upward with respect to the support shaft 5, the device of the present invention can be realized with a structure in which the paper tray 1 is fixed and the support shaft 5 is lowered.

<< Advantages of the Invention >> According to the apparatus of the present invention described above, it is possible to suppress the occurrence of double feed when thin paper is fed and the occurrence of pick mistakes when thick paper is fed, and to smoothly feed a wider range of paper types. It is possible to obtain an automatic paper feeding device, and the optimum paper feeding conditions are automatically set according to the nature of the paper, so the operator's work load is not increased and the device structure is simple and the device cost rises. It has the excellent effect of not causing it.

[Brief description of drawings]

1 to 3 are views showing an embodiment of the present invention.
FIG. 1 is a control flowchart, FIG. 2 is a side view of an essential part showing a first paper feed level, and FIG. 3 is a side view of an essential part showing a paper feed level when a paper is thick. FIG. 4 is a side view of a main part showing an embodiment in which a locking claw is used as a resistance member,
FIG. 5 is a side view of essential parts showing a conventional device corresponding to the structure shown in FIGS. In the figure, 1: Paper stand, 2: Stacked paper, 5: Support shaft, 6: Paper feed roller, 7: Level detection sensor, 9: Separation pad, 9a: Locking claw, 10: Paper detection sensor A: Paper feed roller and paper Contact position B with: Collision position between resistance member and paper L: Distance between position A and B

Claims (1)

[Claims] 1. A paper feed roller (6) that rotates in contact with the upper surface of stacked paper (2) on a paper tray (1), and a resistance member (9, 9a) for separating the paper sent by the roller. ) And a paper detection sensor (10) for detecting the paper sent out beyond the resistance member,
The abutting position (A) between the paper feed roller (6) and the upper surface of the stacked paper (2) and the collision position (B) between the leading end of the paper and the resistance member (9, 9a) to be fed out are The paper feed roller (6) has a structure in which the distance (L) between the positions (A) and (B) is widened as the paper table (1) is moved up relative to each other.
Alternatively, the resistance member (9, 9a) is attached, and the level detection sensor (7) for detecting the level that first gives the rotation instruction to the paper feed roller (6) and the paper detection sensor (1
0) does not detect the sheet, the automatic paper feeding means is provided with a control means for rotating the paper feeding roller (6) again after raising the paper tray (1) by a predetermined amount. apparatus.