JPH0512255B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method of controlling a paper feeding device, and in particular,
The present invention relates to a method of controlling a paper feeding device with short paper feeding intervals.

[Prior Art] In recent years, the processing speed of devices such as copying machines and printers that form hard copies using cut paper has been improved, and their working efficiency has been improved. Along with this, in these devices, the paper feeding speed of the paper feeding device that supplies cut paper to the recording section has been improved, and
There is a need to shorten the paper feeding interval as much as possible.

However, if the paper feeding interval is extremely short (for example, 30
In the past, there were the following problems in order to achieve a diameter of less than mm).

Normally, in a paper feeding device, paper stacked on a paper feeding tray or the like is fed out by a paper feeding roller, separated one by one by a pair of separation rollers (separation conveyance means), and at a predetermined timing, the paper is transferred to the next pair of conveyance rollers (for example, for copying). In the machine, it is transported to the registration rollers). Therefore, when multiple sheets of transfer paper are fed by the paper feed roller, the feeding start position is different for the first transfer paper and subsequent transfer sheets, and as a result, paper feed control cannot be performed under the same conditions. It often happens that this cannot be carried out and two sheets of paper overlap on the pair of transport rollers.

The separation roller separates the paper sheet by sheet based on the difference in the stiffness that occurs between the separation roller and the paper and the stiffness that acts on the paper, and as a result, there is a gap between the separation roller and the paper. This causes a slip phenomenon. The amount of slip that occurs between the separation roller and the paper due to this phenomenon is due to factors such as differences in the surface stiffness coefficient and material depending on the type of paper, and the pressure of the separation roller. It varies significantly by ~40%.

Therefore, if the time from when the separating rollers are activated until when they are stopped is controlled to be constant, a situation arises in which the registration rollers are activated without the transfer paper being held between the pair of conveying rollers.

[Objective] The present invention has been made in view of the above-mentioned circumstances, and includes disposing a paper detector immediately after the separation conveyance means and immediately before the conveyance roller pair, and adjusts the discharge speed of the separation conveyance means to the conveyance speed of the conveyance roller pair. A paper feeding device control method that can shorten the paper feeding interval by setting the paper feed control start position to a constant value and changing the operating time of the separating and conveying means according to the amount of slip. The purpose is to provide.

[Configuration] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows a paper feeding device according to an embodiment of the present invention, which constitutes a paper feeding section of a copying machine in this embodiment.

In the figure, 1 is a paper contact plate that aligns the leading edges of the stacked papers PA, 2 is a paper feed roller that feeds out the papers PA sequentially from the top, and 3 and 4 are an upper separation roller and a lower separation roller that form separation and conveyance means. Yes, this lower separation roller 4 is stopped.

5 is a guide plate that guides the paper PA sent out by the paper feed roller 2 to a pair of separation rollers; 6 and 7 are registration rollers that send the paper PA to a transfer section (not shown);
8 is the paper transfer from the separation roller pair to the registration roller pair
A guide plate 9 that guides the PA is a guide plate that guides the paper PA sent by the pair of registration rollers to the transfer section.

Further, the paper sensor 10 is located immediately after the separation roller pair.
A paper sensor 11 is placed immediately in front of each pair of registration rollers. Note that this paper sensor 10,1
1 consists of an optical sensor or a micro switch, etc., which has fast rise and fall characteristics of the detection output.

FIGS. 2 and 3 show the power transmission mechanism of each of the rollers described above.

Power from a motor (not shown) is applied to a registration clutch (electromagnetic clutch) attached to the shaft of the registration roller 8 via a timing belt 21, a timing pulley 21a, a shaft 22, and an intermediate gear 23.
24, and is also applied via a pulley 25 attached to the shaft 22 and a timing belt 26 to a paper feed clutch 27 that drives the paper feed roller 2 and the upper separation roller 3.

The shaft output of the paper feed clutch 27 is output from the coupling 2.
8 and the upper separation roller 3 via the intermediate gear pair 29
It is also transmitted to the paper feed roller 2 via the intermediate gear 30.

31 is a registration brake (electromagnetic brake) that stops the shaft of the registration roller 8; 32 is a second side plate of the copying machine housing; 33 is a rear side plate; 34 is a front side plate;
It is pressed against the registration roller 8 by the. Further, the lower separation roller 4 is supported by an arm member 37 and is pressed against the upper separation roller 3 by a spring 38. In addition, 39, 40, 41, 4
2, 43 and 44 are all one-way clutches.

FIG. 4 shows the control system of this embodiment. This embodiment serves as the paper feed section of a copying machine as described above, so
It is controlled together with other parts 46 of the copying machine by a main body control section 45 of the copying machine. Further, 47 is an operation display section of this copying machine, and 15 is a motor serving as a power source. The main body control unit 45 changes the control signals SR and SF of the registration clutch 24 and the paper feed clutch 27 and controls the registration brake 31 based on the states of the detection signals S ₁ and S ₂ applied from the paper sensors 10 and 11. .

With the above configuration, when the operator presses the start button on the operation display section 47, the main body control section 45 sends a signal at time _t0 after completing the initial processing of each part of the main body.
Set the logic level of SF to "H" (see Figure 5a). As a result, the paper feed clutch 27 is turned on, the paper feed roller 2 and the upper separation roller 3 are rotated, and the uppermost paper PA1 is sent out. And the sixth
As shown in Figure a, at time _t1 when the paper PA1 is detected by the paper sensor 10 and the logic level of its output signal _S1 (see Figure 5c) becomes "H", the logic level of the signal SF changes. It is set to "L" and paper PA1 is temporarily stopped.

The main body control unit 45 outputs the signal again at a predetermined time _t2 .
The logic level of SF is set to "H" and paper PA1 is conveyed, and from this time _t2 , a timer (not shown) is started, and paper PA1 is detected by paper sensor 11 and its output signal _S2 (see Figure 5 d) ) stops this timer at time _t3 when the logic level of
The time T from time t ₂ to time t ₃ is measured. Then, the delay time Td ₁ obtained by applying the following equation () to this time T is the time t ₄ that has passed from the time t ₃ .
Set the logic level of signal SF to "L" and print paper PA1.
Stop transporting.

Td ₁ =(T/4)+α...() However, α is a constant and has a value of approximately 2% of the time T. Note that when a stepping motor is used as the motor 15, if the number of drive pulses corresponding to time T is a, then the number of drive pulses _D1 corresponding to delay time _Td1 is obtained by the following equation ().

D ₁ =(a/4)+6...() However, the constant 6 is the converted value of the constant α in the above equation ().

As a result, as shown in Figure 6b, the paper
After PA1 comes into contact with the registration rollers 7 and 8, it is further fed a predetermined distance and is given a predetermined amount of deflection.

Thereafter, the main body control unit 45 sets the logic level of the signal SR (see FIG. 5b) to "H" at a predetermined timing _t5 synchronized with the control of the exposure system and photosensitive system (not shown), so that the paper PA1 is transported to the transfer section.

In this way, the first sheet PA1 is first fed.

As shown in FIG. 6c, at time _t10 when the trailing edge of the paper PA1 passes the paper sensor 10, the main body control unit 45 sets the logic level of the signal SF to "H" and sends the second paper PA2. The paper PA2 is fed out and stopped once when the paper PA2 is detected by the paper sensor 10 in the same way as the paper PA1. Then, at a predetermined timing, the logic level of the signal SF is set to "H" again, and the paper PA2 is
transport will be resumed. Note that the time interval until the paper PA2 is restarted is set to such an extent that the paper PA2 does not catch up with the previous paper PA1.

Thereafter, when _{the trailing edge of the paper PA1 is detected by the paper sensor 11, the signal SR is output at time t21 ( see} FIG.
The logic level of is set to "L" (see Figure 6e).
Note that the delay time Td ₂ is longer than the time required for the trailing edge of paper PA1 to be reliably fed out by the registration rollers 7 and 8 from time t ₂₀ , and for the next paper PA2 to be fed out by the registration rollers 7 and 8 from time t _20. It is set smaller than the arrival time.

Then, like the paper PA1, the paper PA2 comes into contact with the registration rollers 7 and 8 while being given a predetermined amount of deflection (see FIG. 6f), and waits for the registration timing. Regarding paper PA2, the paper
In the same way as PA1, measure the time from the re-drive timing of the paper feed roller 2 and upper separation roller 3 to the time when they are detected by the paper sensor 11, and calculate the delay time Td ₁ by applying the above equation () to this measured value. Calculate.
This action is performed on each subsequent sheet,
Therefore, even if the amount of slip of each sheet is different, the amount of deflection is constant when the sheets stand by in contact with the registration rollers 7 and 8, and the deviation in the position of the leading edge of the sheets at the transfer section can be kept to an extremely small level. can.

FIG. 7 shows each time and the position of each sheet in the sheet feeding control of the sheets PA1 and PA2 described above. In the figure, the detection delay time due to the on/off characteristics of each paper sensor 10, 11 and the delay time due to the operating characteristics of the registration clutch 24 and paper feed clutch 27 are taken into consideration.
CD ₁ , CD ₂ , CD ₃ , CD ₄ , CD ₅ represent clutch delay times, and the delay times SD ₁ , SD ₂ , SD ₃ ,
SD ₄ shows the paper sensor delay time. Further, the distance L indicates the amount of deflection of the paper.

By the way, the present invention can be applied not only to the above-mentioned embodiments but also to a paper feeding mechanism provided with a transport roller RR between a pair of separating rollers and a pair of register rollers, as shown in FIG. In this case, the transport roller RR
may be driven and controlled by an independent clutch, or may be constantly rotating.

Further, as shown in FIG. 9, if the distance between the paper feed position and the pair of registration rollers is long and there are two or more paper feed ports, a pair of pre-registration rollers 7' having a clutch in front of the pair of registration rollers may be used. , 8' are provided,
Although sheet control is performed once using this pair of pre-registration rollers, and finally registration is performed using a pair of registration rollers, the present invention can also be applied to an apparatus having such a sheet feeding mechanism. however,
In this case, the paper sensor 11 is placed immediately before the pair of pre-registration rollers as shown in the figure, and the pair of pre-registration rollers is controlled in the same manner as the pair of registration rollers in the above embodiment.

Furthermore, as shown in FIG. 10, the present invention can also be applied to a paper feeding mechanism in which a pair of conveying rollers RP having a clutch is arranged in close proximity to a pair of separating rollers. However, in this case, as shown in the figure, a paper sensor 10 is provided immediately after the conveyance roller pair RP, and the paper sensor 10 is connected to the paper feed roller 2, the upper separation roller 3, and the conveyance roller pair RP.
control synchronously.

Further, in the above-described embodiments, the separation mechanism has a structure in which the lower separation roller is stopped, but it may have the following various structures.

The lower separation roller rotates constantly or intermittently.

A device that applies a constant torque reversal force to the lower separation roller.

The paper feed and separation are integrated, and the separation pad comes into contact with the paper feed roller to separate the sheets one by one.

Separate and feed using a separation belt and lower separation roller.

Something that can be separated with a separation claw.

[Effects] As explained above, according to the present invention, the paper is temporarily stopped when it is separated, and is transported to the next stage transport roller at a speed higher than the transport speed of this transport roller. The amount of paper deflection during standby is kept constant, and as a result, paper feeding intervals can be made extremely short, and even if the slip amount (rate) varies from paper to paper, stable paper feeding is possible. It has the advantage of being .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the device according to the present invention, FIG. 2 is a schematic diagram showing an example of a drive system,
Fig. 3 is a side view showing the drive system, Fig. 4 is a block diagram showing an example of the control system, Figs. 5 a to d are waveform diagrams for explaining the operation of the control system, and Figs. f
is a schematic diagram showing an example of the control mode, FIG. 7 is a graph diagram showing the relationship between control timing and paper position, and FIG. 8 is a schematic diagram showing another example of the paper feeding mechanism.
FIG. 9 is a schematic diagram showing still another example of the paper feeding mechanism, and FIG. 10 is a schematic diagram showing still another example of the paper feeding mechanism. 3... Upper separation roller, 4... Lower separation roller, 1
0, 11... Paper sensor, 24... Registration clutch, 45... Main body control section.

Claims (1)

[Scope of Claims] 1. A method for controlling a paper feeding device in which stacked sheets are sent out by a paper feeding roller and then transported to the next pair of transport rollers by a separating transport means, wherein the paper is separated by the separating transport means. A first paper detector that detects the paper; and a second paper detector that detects the paper immediately before being sandwiched between the pair of transport rollers;
The conveyance speed of the separation conveyance means is set to a value obtained by multiplying the conveyance speed of the conveyance roller pair by a predetermined value larger than 1, and when the first paper detector detects the paper, the conveyance speed of the separation conveyance means After stopping, the separating and conveying means is operated again at a predetermined paper feeding timing, and after a predetermined time from the time when the second paper detector detects the paper, the separating and conveying means is stopped again to keep the amount of deflection of the paper constant; A method of controlling a paper feeding device, characterized in that the pair of transport rollers is operated at a predetermined transport timing, and then the next sheet of paper is fed out when the trailing edge of the sheet is detected by a first paper detector. 2. In claim 1, the predetermined time is based on the time from the time when the separation and conveyance means is activated again to the time when the second paper detector detects the paper. A control method for a paper feeding device, characterized in that it is updated every time it is transported.