JPH03259858A - Automatic original feeder for document - Google Patents

Abstract

PURPOSE:To smooth a turnover of thick and thin sheets of paper by comparing the paper thickness detected by a thickness detecting means with the reference value, and on the basis of the compared result, varying the pressurizing force of a pressure roller. CONSTITUTION:Thickness of an original being supplied is detected by a sensor, fed to an interval between contact glass 1 and a belt conyor 2 and one side is exposed to light, then the original is turned over and conveyed to a paper discharge part 6. When a turnover command is issued, it is conveyed after being held between a turnover roller 16 and a pressure roller 17, while a turnover selector claw 18 is selected to the upper part, and the original turned over is put back to top of the contact glass, then the backside is exposed to light. Then, the selector claw 18 turns downward and the returned original is discharged out of a discharge port 23. Paper thickness detected by a thickness sensor is compared with the specified reference value, and when it is larger than the reference value, pressurizing force of the pressure roller 17 is increased by a solenoid 22, so that even when the paper thickness is large enough, original turnover operation can be done in this way. In addition, when it is thin, the pressuring force is decreased, through which such a fear of wrinkles or the like at time of the original is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic document feeder in a copying machine that is capable of inverting a document in a reversing/discharging section and copying both sides of the document.

2. Description of the Related Art Conventionally, there has been a copying machine that has a reversing/discharging section and is capable of reversing a document in the reversing/discharging section and automatically copying both sides of the document. - The paper ejecting section is composed of a reversing roller driven by a motor, a pressure roller that comes into contact with the outer circumferential surface of the reversing roller, and a reversing switching claw that switches the document conveyance path between the reversing direction and the paper ejecting direction. There is.

Problems to be Solved by the Invention As the paper thickness of the manuscript becomes thicker and the stiffness of the manuscript becomes stronger,
The reversing performance at the reversing/discharging section deteriorates, causing slips during reversing, causing pressure roller marks on the document, jamming, and damage to the document.

Here, the paper thickness of the document that can be reversed in the reversing/discharging section is determined by the diameter of the reversing roller and the pressing force of the pressure roller.
As the pressing force of the pressure roller increases, the thickness of the document that can be reversed increases.

Therefore, by increasing the diameter of the reversing roller and increasing the pressing force of the pressure roller, it becomes possible to reverse a cardboard original. However, increasing the diameter of the reversing roller may not be possible due to the layout, and increasing the pressing force of the pressure roller may cause the document to wrinkle or tear when reversing a thin document. There are cases.

Therefore, we have installed a sensor that detects the paper thickness of the original, and when it is detected that the paper thickness is greater than a preset value, the operator can hold the original on the contact glass with one side exposed. There are copying machines equipped with a pressure plate mode in which the original is turned over manually. Although this kind of copying machine is effective in terms of protecting the original,
The function of the automatic document feeder has deteriorated significantly.

Means for Solving the Problem In a copying machine equipped with a reversing/discharging unit having a reversing roller and a pressure roller that is in contact with the outer circumferential surface of the reversing roller, the paper thickness of a fed document is detected. a paper thickness detection means; a comparison means for comparing a detection result by the paper thickness detection means with a preset reference value; and an application for changing the pressing force of the pressure roller based on the comparison result from the comparison means. A pressure regulating means was provided.

The paper thickness of the document is detected by the paper thickness detection means, the comparison means compares the detection result by the paper thickness detection means with a preset reference value, and the pressing force is applied based on the comparison result from the comparison means. The pressure roller's pressure is adjusted by the adjusting means, and in the case of thick documents, the pressure roller's pressure is increased to increase the conveying force of the document, allowing the document to be reversed at the reversing/discharging section. Make it.

Example An embodiment of the present invention will be described based on the drawings.

First, an outline of an automatic document feeder in a copying machine will be explained based on FIG. A conveyor belt 2 is provided at a position that covers the upper part of the contact glass 1. At one end of the conveyor belt 2, there is a call roller 4 that calls out documents set on a document table 3'' one by one.
A conveyance roller 5 and the like are provided for conveying the document called out between the conveyance belt 2 and the contact glass 1. On the other hand, on the other end side of the conveyor belt 2, there is provided a reversing/discharging section 6 for reversing or discharging the document whose one side has been exposed on the contact glass 1.

As shown in FIGS. 2 and 3, on the document feeding side where the calling roller 4 and the like are provided, a document 8 to be fed is located between the conveyance roller 5 and the registration sensor 7. A paper thickness measuring section 9 is provided to measure the paper thickness of the paper. The paper thickness measuring section 9 includes a pair of metal rollers 10 and 11 provided sandwiching the conveyance path of the document 8, and a minute displacement detection means that detects displacement of the metal roller 11 in a direction perpendicular to the axis thereof. It is composed of a sensor 12. One of the metal rollers 10 is supported via a bearing 13 on a side plate (not shown) of an automatic document feeder, and the other metal roller 1
1 is supported by a lever 14 and a spring 1
5 in the direction of contacting the outer peripheral surface of the metal roller 10. Further, the minute displacement detection sensor 12
is disposed above one shaft end of the metal roller 11 and is fixed to the side plate of the automatic document feeder.

Further, a comparison means (not shown) is provided for comparing the detection result by the minute displacement detection sensor 12 with a preset reference value.

Note that, as the minute displacement detection sensor 12, for example, a laser type displacement sensor manufactured by Keyence Corporation is suitable.

Next, as shown in FIG. 4, the reversing/discharging section 6 includes a reversing roller 16 driven by a motor (not shown), a pressure roller 17 that is in contact with the outer peripheral surface of the reversing roller 16, and an original document. It is comprised of a reversal switching claw 18, etc., which switches the conveyance path of 8 between the reversal direction and the paper ejection direction. Here, the pressure roller 17 is supported by one end of a lever 2o that is rotatable around a support shaft 19, and the other end of this lever 20 has a
A spring 21 biases the pressure roller 17 in a direction to bring the pressure roller 17 into contact with the outer peripheral surface of the reversing roller 16;
A solenoid 22, which is a pressure adjustment means for changing the pressure applied to 6, is connected to the solenoid 22.

In such a configuration, a case will be described in which the inversion mode is selected and both sides of the document are copied.

Among the documents 8 set on the document table 3, the lowest one is called out by the calling roller 4, and further conveyed by the conveying roller 5 toward the space between the conveying belt 2 and the contact glass 1. The document 8 conveyed by the conveyor belt 2 is temporarily stopped at a predetermined reference position, and one side (the front surface of the document) facing the contact glass 1 is exposed.

After the exposure of one side is completed, the conveyor belt 2 rotates again,
The original document 8 is conveyed toward the reversing/discharging section 6 .

In the reversal/discharge section 6, the reversal switching claw 18 is rotated to the position shown by the solid line, and the document 8 is reversed by the conveyance force based on the pressure from the pressure roller 17, and the document 8 is reversed by the conveyor belt 2. and the contact glass 1. Note that the rotation direction of the conveyor belt 2 is reversed at the timing when the leading edge of the document 8 reaches between the conveyor belt 2 and the contact glass l, and the document 8 is placed so that the other side (the back side of the document) faces the contact glass 1. The document 8 is conveyed in the same state, and is temporarily stopped at a predetermined reference position, and the back surface of the document 8 is exposed.

After the back side of the document 8 is exposed, the rotation direction of the conveyor belt 2 is reversed again, and the document 8 is conveyed toward the reversal/discharge section 6. At this time, in the reversal/discharge section 6, the reversal switching claw 18 is rotated to the position shown by the two-dot chain line, and the original 8
is discharged from the paper discharge port 23.

Here, the measurement of the paper thickness of the original 8 and the adjustment of the pressing force of the pressure roller 17 based on the measurement results will be explained based on FIG. 5. When the original 8 fed from the original table 3 passes between the metal rollers 10 and 11, the upper metal roller 11 is slightly displaced in the direction perpendicular to the axis, and the amount of displacement depends on the paper thickness of the original 8. and change. Then, by detecting the amount of displacement of the metal roller 11 with the minute displacement detection sensor 12, the paper thickness of the document 8 is detected. The determination means determines whether or not the detection result by the minute displacement detection sensor 12 is larger than a preset reference value +1 Aμm. This is the limit value of the filter paper thickness that can be reversed under normal conditions.

If the determining means determines that the paper thickness of the document 8 is equal to or greater than the reference value, the solenoid 2 is activated based on the determination result.
2 is driven, the lever 20 slightly rotates around the support shaft 19 in the direction of arrow A, and the pressing force of the pressure roller 17 against the reversing roller 16 increases. Therefore, the conveyance force for conveying the document 8 is increased, and even if the document 8 is made of thick paper, it can be smoothly reversed.

Note that when the single-sided copy mode is selected, the reversing switching claw 18 is rotated to the position shown by the two-dot chain line from the beginning, and the original that has reached the reversing/discharging section 6 after exposure of one side has been completed. 8
is discharged from the paper discharge port 23.

In this embodiment, the solenoid 22 is used as the pressurizing force adjusting means, but a cam mechanism or the like may also be used.

Effects of the Invention The present invention provides a paper thickness detection means for detecting the paper thickness of a document as described above, a comparison means for comparing the detection result by the paper thickness detection means with a preset reference value, and a comparison means. By providing a pressing force adjustment means that changes the pressing force of the pressure roller against the reversing roller in the reversing/discharging section based on the comparison results of By increasing the force, it is possible to increase the conveying force of the document, and therefore, even if the document is made of thick paper, it can be smoothly reversed at the reversing/discharging section, and damage to the document can be prevented during reversing. In addition, in the case of a thin paper document, by reducing the pressing force of the pressure roller, it is possible to prevent damage when the thin paper document is turned over.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a front view schematically showing an automatic document feeder in a copying machine, and FIG. 2 is a front view showing an enlarged view of the paper feed section side of the automatic document feeder. Fig. 3 is a perspective view showing the paper thickness measuring section, Fig. 4 is an enlarged front view showing the reversing/discharging section side of the automatic document feeder, and Fig. 5 is about adjusting the pressing force of the pressure roller. It is a flowchart explaining. 6...Reversing/discharging unit, 8... Original, 12... Paper thickness detection means, 16... Reversing roller, 17... Pressure roller, 22... Pressure force adjustment means Application People Ricoh Co., Ltd. 1 12

Claims (1)

[Claims] In a copying machine equipped with a reversing/discharging section having a reversing roller and a pressure roller in contact with the outer peripheral surface of the reversing roller, a paper thickness detecting means for detecting the paper thickness of a fed document; Comparing means for comparing the detection result by the paper thickness detecting means with a preset reference value, and pressing force adjusting means for changing the pressing force of the pressure roller based on the comparison result from the comparing means. An automatic document feeder characterized by: