JPH06298411A - Control method for sheet material feeder - Google Patents

Abstract

PURPOSE:To prevent repressing force from being applied to a transport means from the feeding means side by detecting the length of a sheet material at the time of feeding the first sheet material and again operating a feeding means according to the information on the detected sheet material length to auxiliary- feed a sheet material at the time of feeding the second and following sheet materials. CONSTITUTION:Sheet materials 11 are separated one by one by a friction pad 3, the leading end of the sheet material is detected by a sensor 15, and when the trailing end thereof passes, a signal of the sensor 15 is turned off. According to the signal, the length of the sheet material 11 in the transport direction can be detected. For the second and following sheet materials, just after a regist clutch is turned on, a paper feed clutch is again turned on to start auxiliary paper feeding for the sheet material 11. Subsequently, after a designated time, the paper feed clutch is turned off and a frictional rotor 2 is again stopped. Offtiming may be taken before the trailing end of the sheet material 11 passes a contact part between the frictional rotor 2 and the friction pad 3 according to the length in the transport direction of the sheet material 11 obtained at the time of first feeding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a sheet material feeding device, and more particularly to a method for controlling a sheet material feeding device in an image forming apparatus such as a copying machine or a recording machine.

[0002]

2. Description of the Related Art A conventional sheet material feeding device of this type is shown in FIG. That is,
Friction rotator 1 that makes rotational contact with the uppermost sheet material 101a of a large number of sheet materials 101 stacked in the cassette 100
02 and registration rollers 103 and 104 arranged on the downstream side of the friction rotating body 102.

By rotating the friction rotator 102, the sheet material 101a is fed until its leading end abuts the registration rollers 103 and 104, and then the registration rollers 103 and 104 are driven at a predetermined timing to drive the sheet material. 101a is sent further downstream.

At this time, the friction rotator 102 in contact with the rear portion of the sheet material 101a becomes the registration rollers 103,1.
A one-way clutch (not shown) is used in the drive transmission system of the friction rotator 102 so as not to hinder the conveyance of the sheet material 101a by 04, so that the friction rotator 102 idles as the sheet material 101a moves. Was configured into.

Further, in this conventional example, in order to prevent the sheet material 101 from being double-fed, a separation pad 105 which is pressed against the friction rotating body 102 is used, and the sheet material 101 is separated from the friction rotating body 102 and the separation pad. It is designed to pass between the contact surfaces of 105.

[0006]

However, in the case of the above-mentioned prior art, the registration rollers 103 and 104 are used.
Although the friction rotator 102 is made idle while the sheet material 101 is conveyed by the sheet material 101, due to the friction resistance between the sheet materials 101, the sliding resistance of the clutch portion, and the like, the registration roller 10 still remains.
The transportation of 3,104 may be hindered.

In particular, as in this conventional example, the separation pad 1
In the case of using No. 05, the separation pad 105 does not rotate and is kept in pressure contact with the friction rotating body 102, and the surface thereof is made of a material having a high friction coefficient, so that the sheet material 101 is highly blocked. Generate force. Therefore, there is a drawback that the registration rollers 103 and 104 are worn and durability is deteriorated.

In order to solve this problem, it is considered that when the registration rollers 103 and 104 are used for conveyance, the friction rotator 102 is driven again to assist the conveyance of the registration rollers 103 and 104.

That is, as shown in FIG. 7, the projections 106 are provided at different positions on the leading end of the cassette 100 according to the size of the sheet material to be stored and placed, and when the cassette 100 is mounted in the sheet feeding device, The size of the sheet material stored in the cassette 100 is detected in advance by turning on any one of a plurality of switches 107, 108, and 109 provided as detection means on the main body side. Then, the sheet material 101 is formed by the registration rollers 103 and 104.
After the predetermined loop is formed on the friction rotating body 102, the rotation of the friction rotating body 102 is stopped.

After that, when the conveyance of the sheet material 101 by the registration rollers 103 and 104 is started, the friction rotator 1
It is said that the rotation of No. 02 is started, and the rotary feeding by the friction rotary body 102 is stopped after the rotary feeding is performed until the vicinity of the rear end of the length in the transport direction of the sheet material 101 detected by the detecting means is reached. It is a thing.

However, this control method requires the sheet size detecting switches 107, 108 and 109.

Particularly in recent years, an image forming apparatus capable of mounting a large number of cassettes 100 at the same time has been put into practical use in order to save the trouble of replacing the sheet material 101. In this case, a size detection switch is required for each cassette, There is a problem that the device becomes large and the cost becomes high.

The present invention has been made in view of the above circumstances, and provides a control method for a sheet material feeding device, which has a simple structure and can prevent a blocking force from acting on the feeding means from the feeding means side. With the goal.

[0014]

In order to achieve the above object, in the present invention, a feeding means for feeding the sheet materials one by one by frictionally contacting the surface of a large number of stacked sheet materials. A continuous feeding means for feeding the sheet material fed by the friction feeding means further downstream, and a length detecting means for detecting the length of the fed sheet material. During the feeding operation, the length detecting means detects the sheet material length when feeding the first sheet material, and when feeding the second and subsequent sheets, the sheet material is fed by the feeding means. When the sheet is conveyed by the conveying means, the sheet feeding means is operated again on the basis of the detected length information of the sheet material to auxiliary feed the sheet material.

[0015]

In the present invention, the length of the sheet material in the conveying direction is detected during continuous feeding of the sheet material, and based on the detection result, the second and subsequent sheets are fed to the vicinity of the rear end of the sheet material. The sheet material is auxiliary fed by operating the feeding means. Therefore, no resistance acts on the conveying means from the side of the feeding means.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

FIG. 1 shows a sheet material feeding apparatus according to an embodiment of the present invention. That is, it has a friction rotating body 2 as a feeding means which is rotationally driven by the shaft 1 and a friction pad 3 made of a member having a high friction coefficient such as rubber or synthetic resin. The friction pad 3 is fixed to the other end of the separating member 5 which is pivotally supported by the support shaft 5a, and is pressed against the friction rotating body 2 at a predetermined pressure by a spring 6 stretched at the other end of the separating member 5. is doing.

Further, a paper feed cassette 7 which is detachable from the paper feed unit is disposed facing the friction rotary body 2, and the free end of the paper feed cassette 7 is directed toward the friction rotary body 2 by a spring 10. A storage box 9 having a box shape for supporting the biased mounting table 8 and its rotating end 8a and storing the sheet material.
It is composed by.

The sheet material 11 such as a large number of sheets of paper or the like stacked on the mounting table 8 is in contact with the friction rotating body 2 at the top, and the top sheet material 11a is in the direction of arrow A of the friction rotating body 2. It is fed by the frictional force based on rotation.

Further, when two or more sheet materials 11 are fed, the lower sheet material is separated by the pressure contact of the friction pad 3 so as to be separated, and the double feeding of two or more sheet materials 11 is prevented. is doing.

The sheets thus separated one by one are transferred to registration rollers 13 and 14 as a pair of conveying means provided for aligning the powder image on the photosensitive drum 12 with the sheet material. Is sent.

A sensor 15 is arranged on the upstream side of the registration rollers 13 and 14, and a timer that detects the leading edge of the sheet material and measures the time corresponding to the distance between the sensor 15 and the registration rollers 13 and 14. By the means, a signal for controlling the stop timing of the friction rotating body 2 is issued so as to form an appropriate loop between the sensor 15 and the registration rollers 13 and 14.

It is well known that the loop is formed as a means for correcting the skew feeding of the sheet material 11, and the sheet material 11 is emitted from the photosensitive drum 12 or an optical device (not shown) for exposing an image. The rotation of the registration rollers 13 and 14 is started by the obtained image leading edge synchronization signal,
The sheet material is conveyed again, is fed onto the photosensitive drum 12, and the toner image is transferred onto the surface thereof.

Next, the control method will be described with reference to FIGS.

At the same time when the motor 16 starts rotating, the gear 30,
The photosensitive drum 12 starts to rotate via 31, and after a lapse of a predetermined time, the paper feed clutch 17 is turned on and the drive is transmitted to the friction rotator 2 to start the feeding of the sheet material (STEP in FIG. 4).
1 and 2). That is, the rotation of the gear 31 is
The friction rotator 2 rotates via the belt 34, the clutch 17, the pulley 35, and the belt 36.

As described above, the sheet material is separated one by one by the friction pad 3, and when the tip of the sheet material is detected by the sensor 15, the clutch 17 is turned off after a predetermined time a, and the registration rollers 13, 14-rubbing during this period. A loop is formed between the rotating bodies 2 (STEPs 3 to 5).

Next, the registration clutch 19 is turned on by a signal issued by the signal of the clock pulse means 18 which rotates in synchronization with the drum 12 in order to synchronize the developed toner image on the drum 12 with the sheet, and the registration clutch 19 is turned on. Laura 1
The driving force is transmitted to the registration roller 3, and the registration roller 1 further cooperates.
The drive is also transmitted to the sheet 4, and the sheet material is sent out toward the drum 12 (STEP 6). That is, the rotation of the gear 31 is transmitted to the registration roller 13 via the gear 33, the belt 34, the pulley 38, the gear 39, the gear 40, and the clutch 19.

When the trailing edge of the sheet material passes the sensor 15, the signal from the sensor 15 is turned off (STE).
P7).

From this signal, the length L of the sheet material in the carrying direction can be detected. That is, when the distance from the sensor 15 to the registration rollers 13 and 14 is ι, the sheet material conveyance speed is v, and the time from when the registration clutch 19 is on to when the sensor 15 is off is t, the length L of the sheet material in the conveyance direction is , L = vt + ι.

Further, after a lapse of a predetermined time b after the trailing edge of the sheet material passes the sensor 15, the registration clutch 19 is turned off to prepare for the next sheet material to be fed (STEP).
9).

Next, the feeding of the second and subsequent sheet materials will be described (see STEPS 10 to 22).

The sheet feeding clutch 17 is turned on at a predetermined timing to start feeding the next sheet material (STEP 10).

Then, similarly to the first sheet, a loop is formed between the registration rollers 13 and 14 and the friction rotator 2 and the registration clutch 19 is turned on at a predetermined timing (STEPs 11 to 14).

Immediately after the registration clutch 19 is turned on, the paper feed clutch 17 is turned on again to start the feeding assistance of the sheet material (STEP 15). The delay in the on-time of the sheet feeding clutch 17 with respect to the registration clutch 19 takes into account the response speeds of both clutches, so that the sheet feeding clutch 17 is turned on before the registration clutch 19 and the loop becomes excessive to cause buckling of the sheet. This is to avoid danger. In other words, it suffices that the timing at which the sheet feeding clutch 17 is turned on before the friction rotating body becomes a load by causing the loop to disappear due to the on timing being too late.

After a predetermined time, the paper feed clutch 17 is turned off (STEP 17), and the friction rotator 2 is stopped again. The off-timing depends on the length in the conveying direction of the sheet material obtained when the first sheet is fed, and the length from the pressure contact portion between the friction rotor 2 and the friction pad 3 to the rear end of the sheet material that has not been fed yet. Is calculated (STEP 16) before the trailing edge of the sheet material passes through the contact portion between the friction rotor 2 and the friction pad 3.

The steps 18 to 20 are the same as the steps 7 to 9 of the first sheet.

As described above, since the auxiliary feed of the feeding is performed up to the vicinity of the rear end of the sheet material by the friction rotator 2, there is no load on the conveyance of the registration rollers 13 and 14.

The following operation is repeated until the set number of sheets is completed. When the feeding of the set number of sheets is completed, the motor 16 is turned off and the photosensitive drum 12 is stopped (STEP).
21, 22).

Further, in the above-mentioned embodiment, the friction pad 3 which is press-contacted as the friction preventing member is used. However, even if this is a friction rotating body which rotates in the opposite direction to the friction rotating body, the same problem occurs. The present invention is also effective.

Further, the present invention can be applied to a cassette type one using the separating claw 50 as shown in FIG.

As the conveying means, a resist claw may be provided on the upstream side of the registration roller, and the leading end of the sheet material may be brought into contact with the resist claw. At this time, the registration roller is usually called a conveyance roller.

As described above, according to the embodiment of the present invention, in the continuous feeding of the sheet material, the length of the sheet material in the feeding direction is detected by the feeding of the first sheet and the calculation is performed. The durability of the registration rollers 13 and 14 can be dramatically improved by a simple configuration and control such as rotating the friction rotating body backward.

[0043]

As described above, the control method for the continuous feeding of the feeding device according to the present invention is configured such that the feeding means assists the feeding of the sheet material by the feeding means. The conveyance preventing force does not act on the sheet material from the means side, and stable conveyance performance can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sheet material feeding device to which a control method of the present invention is applied.

FIG. 2 is a perspective view of a main part of the sheet material feeding device of FIG.

FIG. 3 is a control block diagram of the apparatus of FIG.

FIG. 4 is a control flowchart of the apparatus of FIG.

FIG. 5 is a schematic configuration diagram of another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a conventional sheet material feeding device.

FIG. 7 is an enlarged view showing a conventional cassette size detection unit.

[Explanation of symbols]

2, 52 friction rotating body (feeding means) 3 friction pad ₄₁ to ₃ switch 7 sheet cassette 8 table 9 containing box 11 sheet material 11a sheet (uppermost sheet) 11b sheets (next paper) 12 photosensitive drum 13, 14 Registration Roller (Conveying Means) 15, 55 Sensor 16 Motor 17 Paper Feed Clutch 18 Clock Pulse Means 19 Registration Clutch

Claims (1)

[Claims] 1. A feeding means for feeding the sheet materials one by one by frictionally contacting the surfaces of a large number of stacked sheet materials, and the sheet material fed by the friction feeding means is further downstream side. Transporting means for transporting the sheet material, and length detecting means for detecting the length of the fed sheet material,
In the continuous feeding operation, the length detecting means detects the sheet material length at the time of feeding the first sheet material, and the feeding means at the time of feeding the second and subsequent sheet materials. When the sheet material is conveyed by the conveying means after being fed, the sheet material is operated again based on the detected length information of the sheet material to auxiliary feed the sheet material. Control method of feeding device.