JPH03211136A - Paper feeding method - Google Patents

Abstract

PURPOSE:To reduce double feed and misfeed by changing air flow blown in to the side face of sheets. CONSTITUTION:Air flow blown in to the side face of sheets 23 from a nozzle 22 is changed to generate vertical motion to the sheets 23 so as to weaken bonding strength due to adhesion between the sheet 23 to be sent out and the sheet 23 below among the stacked sheets 23. As a result, the sheets 23 can be positively separated sheet by sheet to be fed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a paper feeding method for paper, OHP sheets, etc., and more specifically, in feeding these sheets, it is possible to reliably feed one sheet at a time from stacked sheets. The present invention relates to a paper feeding method for feeding sheets.

(Prior Art) Conventionally, in copiers, printers, etc., cut sheets that can be continuously fed have generally been limited to high-quality paper, tracing paper for copiers specified by copier manufacturers, and the like. Since such paper has a low surface smoothness, when the sheets are fed one by one from the stacked sheets, it is rare for the sheets to attract each other and to be fed in duplicate. Moreover, even if double feeding was performed, it was possible to feed out one sheet at a time relatively well using a separating roller, a separating pad, or a separating claw. It was also possible to separate each paper by simply blowing air.

For example, in the paper feeding method described in Japanese Utility Model Application Laid-open No. 59-195128, it is proposed to blow air between the sheets of paper from the rear part of the sheet as it is fed out.
No. 35 proposes a method for improving this by blowing air from the side of the paper feed. The method of blowing air between the sheets from the front of the paper when feeding the paper is disclosed in Japanese Patent Application Laid-open No. 62-249835 and Japanese Patent Laid-open No. 60-4443.
This is proposed in Publication No. 5.

However, recently, market demands have become more diverse, including color, and there is an increasing demand for copying or printing on papers with smooth surfaces, such as highly transparent tracing paper, glossy art paper, and coated paper. It's coming. Such sheets tend to attract each other, so even if air is blown, air is not blown to all of the stacked sheets, resulting in double feeding. Similarly, OHPs with high surface smoothness also have similar problems.

(Problems to be Solved by the Invention) The present invention has been made in view of these circumstances, and uses air blowing means to solve the problem without being limited by thin paper, smooth surface paper, thick paper, etc. The purpose is to reliably feed one sheet at a time.

(Means for Solving the Problems) The present invention is a sheet feeding method characterized by changing the air flow blown into the side surface of stacked sheets using an air blowing means. Here, the side surface of the sheet may be any of the front, rear, or side with respect to the sheet feeding direction, and the sheet refers to plain paper used in paper feeding devices such as copying machines and printers, The sheet is made of paper, high-quality paper, tracing paper, OHP, etc., and the manner in which the air flow is changed is not limited to intermittent blowing, changing the flow velocity or pressure, but also changes in the blowing direction. It may also be a combination of these.

(Function) In a sheet feeding method having an air blowing means, the air flow blown into the side surface of the sheet changes to cause the sheet to move up and down, so that the stacked sheets tend to be fed out. The bonding force caused by close contact between a sheet and the sheet below it can be weakened, and the fed sheets can be reliably separated one by one.

(Embodiment) FIG. 1 shows an apparatus for explaining one embodiment of the present invention.
(A) is a side view in which the air blower of this embodiment is omitted, (B) is a rear view, and FIG. 2 is a perspective view of the protruding roll housing.

In the figure, reference numeral 1 denotes a main body of a paper feeder, and sheets 23 stacked on this paper feeder are held in a paper feed tray 10, and the paper feed tray 10 supports a protruding roll 2 according to the number of sheets to be fed. The protruding roll housing 3 is moved upward in small steps so as to come into contact with the top of the paper 23 under its own weight. The ejector roll housing 3 is rotatable around the paper feed roll shaft 6a, and when the tray 10 rises, the uppermost surface of the paper 23 comes into contact with the ejector roll 2, and the ejector roll housing 3 is pushed upward slightly. As shown in FIG. 2, the position detection means 5 is arranged so as to stop. The position detection sensor 5 for operating the paper feed tray 1 is a second
As shown in the figure, it consists of a convex portion 50, which is a shielding member for detection, provided on a part of the protruding roll housing 3, and a corresponding photo sensor 51 disposed on the main body of the paper feeder. There is. On the downstream side of the ejection roll 2, a paper feed roll 6 and a separation roll 7 are provided which are in contact with each other with appropriate pressure in order to prevent double feeding of the sheets 23 fed by the ejection roll 2. The paper feeding device 1 is equipped with a side guide plate 8 that defines the position of one side of the paper, and a movable stop plate 9 that regulates the other end which changes depending on the paper size.

A small blower 20 is attached to a part of the side guide plate 8 and blows an air flow. The small blower 20 used a motor rated at 24 V DC and 0.3 A. A nozzle 22 having an air outlet 21 is connected to a small blower 20 in order to create an air flow to a portion of the stack near the delivery point. The length of the air outlet 21 may extend over the entirety of the facing paper, or may extend over a portion thereof, and its shape is not particularly limited. As shown in FIG. 3, the position of the air outlet 21 is such that the lower part A of the opening is below the upper surface B of stacking paper, and the upper part C of the opening is higher than this upper surface B of stacking paper. It was a favorable condition to achieve the objective. The air blowing timing of the small blower 20 that blows air is made intermittently. FIG. 4 shows the relationship between the time for guiding the air, the copy start, the driving of the protrusion row 2, and the timing of air blowing. Although the air blowing and supply timing can be set arbitrarily, for example, in a 400 PM copying machine, if the ON time and OFF time are set to 4 seconds to 1 second and 2 seconds to 1 second, good results can be obtained. Ta. The reason why the air is blown intermittently in this way is to ensure that the paper is completely separated. FIG. 5 shows the floating state of paper when air is continuously blown. Because air is constantly being pumped in, the shape of the paper is high and stable, and some of the first sheets are not exposed to air and are stable because they overlap. In other words, there is no air between the overlapping papers at the top,
Some items remained in close contact with each other, causing double conveyance. This condition is affected by the weight of the paper and the positional relationship with the air outlet, so depending on the type of paper, air blowing can be resolved to some extent by setting the optimal values for the position and strength of air blowing. However, the inventor has found that it is not practical to change the setting conditions for each paper. Therefore, the inventor discovered that air blowing can be performed intermittently. FIG. 6 is a diagram showing the floating state of paper when air is blown intermittently. The paper stabilizes in a floating state as shown in the figure (A), and before the top few sheets overlap, it floats as shown in the figure (B).
When the air blowing is cut off, the paper returns to its lowered state, and by repeating the presence and absence of the air blowing, air is blown between the sheets of paper. It has been found that when blowing air from the side while paper is being fed, the air outlet is preferably located within a range of about 115 to about 415 from the leading edge of the paper. This is because when air is blown from the edge of the paper, the moment applied to the paper lifted by the air increases, which often causes the paper to skew.

Therefore, the position of the air feed port may be moved depending on the length of the paper, or the most commonly used paper A-3~
The optimum position among the combinations of B-5 may be determined in advance. Further, the setting position of the paper may be changed depending on the air outlet. As an example, an experiment was conducted using an A-4 size OHP sheet, which is a typical sheet with a very smooth surface and high adhesion between sheets. The OHP was taken out of the box without being handled in any way and placed in the paper feed tray 10. The experiment was conducted at a paper feeding speed of 40 sheets per minute. The results were as shown in Table 1.

Table 1 shows the results of comparative experiments when air was not blown, when air was blown continuously, and when air was blown in an intermittent mode. The numbers here represent the number of copies in which the problem occurred relative to the number of tests. As shown in Table 1, it was found that by performing intermittent air blowing, performance against double feeding and feeding errors was significantly improved. As with OHP, stable paper feeding performance was obtained even with smooth papers such as art paper and tracing paper. FIG. 7 is an enlarged view of a blowing section for explaining another embodiment, in which the blowing state of the blowing port of a small blower is changed by an appropriate shutter or blowing direction guiding member.

At the entrance of the air outlet, an air shielding member 33 rotates about a central axis 34 between the solid line and the broken line position. By doing so, the air flow alternately blows against the upper and lower parts of the stacked sheets, and the air is evenly sent between the stacked sheets.

Alternatively, the air outlet for blowing air onto the paper may move up and down with respect to the side surface of the stack of paper.

A similar effect can be obtained by attaching a shutter to the air outlet and opening and closing it instead of intermittent driving the blower. In the above embodiments, the case where the air is blown from the side in the paper feeding direction has been described, but it goes without saying that the air may be blown from the rear or the front of the paper in the feeding direction.

The paper feeding system of the present invention has been described using a paper feeding roll and a separation roll, and is fed while being sorted, but sufficient effects can also be obtained with a paper feeding system having corner claws 31 as shown in FIG. It is.

(Effects of the Invention) As explained above, according to the present invention, it is possible to separate sheets such as coated paper, art paper, OHP paper, plain paper, etc. without depending on differences in their surface roughness or weight. By being able to do this stably and evenly, it has become possible to significantly reduce errors in electronic and paper feeding. Furthermore, by changing the air flow to the paper not only by intermittent air flow or changing the direction, but also by changing the flow velocity, changing the flow velocity distribution, or by combining them, it is possible to There are unexpected effects.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a paper feeding device for explaining the present invention, FIG. 2 is a configuration diagram of the ejecting roll section, FIG. 3 is a layout diagram of the positional relationship with the air outlet, and FIG. 5 is an explanatory diagram of the effect of the conventional method, FIG. 6 is a detailed explanatory diagram of the present invention, FIG. 7 is an explanatory diagram of another embodiment, and FIG. 8 is an explanatory diagram of the ventilation timing. , is a perspective view of a paper feed tray using corner claws. (11) ...Paper feeding device main body 2..Ejecting roll, ejecting roll housing...Paper feeding roller 7..Paper feeding tray 20 Air outlet 22..Paper...Small blower separation roll...Nozzle ( 12) Figure 5 (・A) Figure 7

Claims (1)

[Claims] A sheet feeding method from stacked sheets having an air blowing means, characterized in that the air flow blown into the side surface of the sheet is changed.