JPH04201932A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To avoid affection upon deflection between a register roller couple and a relay roller couple by rotating transport roller couples for a certain period from immediately before the drive of the relay rollers is stopped, and controlling that part of an applicable sheet of paper which is situated between the relay rollers and the transport roller couples so as to deflect. CONSTITUTION:Transport roller couples 28-34 are coupled with a drive power supply via a spring clutch, and when a certain period of time has passed since a relay roller switch 55 was turned on, its drive is stopped, and a relay roller couple 54 is stopped rotating after elapse of a specified period of time since a resist switch 60 was turned on. Therein transport roller couples 28-34 are rotated only for a certain while from immediately before the drive of the relay roller couple 54 is stopped, and that portion of the sheet which is situated between the relay roller couple 54 and transport roller couples 28-34 is deflected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device, and more particularly to a paper feeding device applied to an image generating machine such as an electrostatic copying machine or an electrostatic printing machine.

[Conventional technology]

An example of a conventional paper feeding device will be explained with reference to FIGS. 3 and 4. First, in FIG. 3, a paper feeding device, generally designated by the number 2, is provided within the electrostatic copying machine main body 4. As shown in FIG. The main body 4 is divided into an upper chamber 8 and a lower chamber 10 by a horizontal partition member 6.

In the lower chamber 10, four paper feed cassettes 12, 14, 16 and 18 are arranged one above the other in that order.

Each of the paper feed cassettes 12 to 18 is provided with paper feed rollers 20, 22, 24, and 26 for feeding (feeding) the paper (copy paper) P stored inside the cassette 7 to the downstream side. ing. In the lower chamber 10, on the downstream side of each of the paper feed rollers 20 to 26, a pair of transport rollers 28, 30 are provided.
．． 32 and 34 are arranged in that order from the top. A paper feed path 36 is provided between the paper feed roller 20 and the transport roller pair 28; hereinafter, a paper feed path 38 is provided between the paper feed roller 22 and the transport roller pair 30; A paper feed path 40 is provided between the roller pair 32 and a paper feed path 42 is provided between the paper feed roller 26 and the transport roller pair 34.

Further, a conveyance path 44 is provided between the conveyance roller pair 28 and the conveyance roller pair 30, and a conveyance path 46 is provided between the conveyance roller pair 30 and the conveyance roller pair 32, and a conveyance path 46 is provided between the conveyance roller pair 30 and the conveyance roller pair 32.
A transport path 48 is provided between each of the transport rollers 2 and the transport roller pair 34. In this example, the conveyance paths 44 to 48 are each formed so that the paper P is conveyed upward. A conveyance path 50 is provided on the downstream side of the pair of conveyance rollers 28 located at the uppermost position so that the paper P is conveyed upward, and the conveyance path 50 passes through the partition member 6 to the upper chamber 8 side. Some of them stand out. A conveyance roller switch 31 is provided upstream of the conveyance roller pair 30.

On the upper chamber 8 side, a conveyance path 52 is provided on the downstream side of the conveyance path 50, and a relay roller pair 54 is provided on the downstream side of the conveyance path 52. A relay roller switch 55 is provided on the upstream side of the relay roller pair 54, and a conveyance path 56 is provided on the downstream side of the relay roller pair 54. A registration roller pair 58 is provided on the downstream side of the conveyance path 56. A registration switch 60 is arranged on the conveyance path 56 upstream of the registration roller pair 58 . In this example, the conveyance path 52 is curved so that the sheet P conveyed vertically upward from the conveyance path 50 is turned horizontally and conveyed to the relay roller pair 54 .

The conveyance roller switch 31, the relay roller switch 55, and the registration switch 60 are each known detection switches (sensors) that detect passage of the leading edge of the paper.

Of the four conveyance roller pairs 28 to 34, the upper conveyance roller pairs 28 and 30 are each connected to a drive source via a common spring clutch (not shown). Further, the pair of transport rollers 32 and 34 located at the lower stage are each connected to a drive source via a common spring clutch (not shown), which is different from the one described above. These spring clutches are well known mechanical spring clutches that include coil springs.

This spring clutch includes, for example, an output shaft and an input gear (or pulley) rotatably supported on the output shaft. A cylindrical output boss having a larger diameter than the cylindrical portion is fixed to the output shaft, and a portion of the output boss has a portion having a larger diameter than the cylindrical portion, and a stepped portion is formed therebetween. A cylindrical manual boss with a smaller diameter is fixed to the input gear. The outer diameters of the respective cylindrical portions of both bosses are formed to be the same diameter, and the respective ends are arranged so as to abut each other. A coil spring, which is a clutch spring, is fitted to the outer diameter of each cylindrical portion of both bosses, and a collar is fitted to the outer periphery of the coil spring. One end of the coil spring is connected to the collar. A plurality of claws are formed on the outer periphery of the collar. A locking lever is disposed near the collar and is always biased in a direction to lock the claw of the collar. The locking lever is configured to be disengaged from the claw of the collar when the solenoid is turned on, and to come into contact with the claw of the collar when the solenoid is turned off to prevent rotation of the collar.

Therefore, by turning on the solenoid, the rotation of the input boss of the manual gear tightens the inner diameter of the coil spring, is transmitted to the output boss via the coil spring, and the output shaft is rotationally driven (the spring clutch is connected). With the solenoid OFF, the rotation of the input boss idles in the inner diameter portion of the coil spring and is not transmitted to the output shaft (disconnection of the spring clutch). Note that since the other end of the coil spring is not connected to the output shaft side, the output shaft can freely rotate when the spring clutch is released. This output shaft is connected to the shaft of the conveyance roller, and the input gear is connected to a drive source.

The above-described spring clutch is controlled to be connected and disconnected by a well-known control means (not shown). When the spring clutch is connected, the conveyance roller is rotationally driven, and when the spring clutch is disconnected, the rotational drive of the conveyance roller is stopped.

Next, the control operation of the conventional paper feeding device 2 configured as described above will be explained with reference to FIG. 4.

When an operator turns on one of the cassette selection keys (not shown) provided on the electrostatic copying machine main body 4, the type of paper P in one of the paper feed cassettes 12 to 18 is selected. Now, for example, the operation of the paper feed device 2 when the cassette selection key is turned on to feed the paper P in the second paper feed cassette 14 from the top will be described.

As shown in FIG. 4, when a print key (not shown) provided on the electrostatic copying machine body 4 is turned on, the paper feed roller 22 rotates at a predetermined timing, and paper P is fed from the paper feed cassette 14. The paper is sent to a pair of transport rollers 30 via a paper path 38. Eleven seconds after the print key is turned on, the conveyance roller switch 31 is turned on. Conveyance roller switch 3
12 seconds after 1 is turned on, the conveyor roller pair 28 and 3
0 spring clutches are connected at the same time, and the conveyor roller pair 2
8 and 30 are rotated at the same time. The paper P is conveyed to the relay roller pair 54 in this order by the conveyance roller pair 30 and 28.

When the leading edge of the paper P reaches the relay roller switch 55, the relay roller switch 55 is turned on. After T3 seconds after the relay roller switch 55 is turned on, the transport roller pair 2
The spring clutches 8 and 30 are simultaneously disengaged, and the rotational drive of the pair of transport rollers 28 and 30 is simultaneously stopped. At the same time, the relay roller pair 54 is rotated. When the leading edge of the paper P sent by the relay roller pair 54 reaches the registration switch 60, the registration switch 60 is turned ON.
becomes. 14 days after the registration switch 60 is turned on
After a second, the rotational drive of the relay roller pair 54 is stopped. The leading edge of the paper P stops moving while being blocked by the pair of registration rollers 58. In the portion of the paper P located between the registration roller pair 58 and the relay roller pair 54,
A known deflection is formed.

Thereafter, the pair of registration rollers 58 is driven to rotate at a predetermined timing, and the paper P is sent to the image forming apparatus side, where a well-known transfer action is performed.

In the above-mentioned conventional paper feeding device, the reason why the rotation of the pair of transport rollers 28 and 30 is stopped at the same time as the pair of relay rollers 54 is rotationally driven is as follows.

That is, since the distance from each paper feed cassette 12 to 18 to the relay roller pair 54 is relatively long, in order to increase the copy processing speed, the rotational speed of each conveyance roller pair 28 to 34 including the conveyance roller pairs 28 and 30 is , is generally set higher than the rotational speed of the registration roller pair 58 and the relay roller pair 54 (same speed as the rotating drum in the image forming apparatus).

Therefore, the relay roller pair 54 and each of the transport roller pairs 28 to 34 cannot be driven to rotate simultaneously to feed the paper.

Note that the control means and control functions of the above-mentioned parts in the above-mentioned conventional paper feeding device are well known to those skilled in the art, and therefore,
I will stop at the above explanation.

[Problem to be solved by the invention]

In the conventional paper feeding device, as described above, T3 seconds after the relay roller switch 55 is turned on, the spring clutches of the conveying roller pairs 28 and 30 are simultaneously released, and the conveying roller pairs 28 and 30 are simultaneously disconnected. At the same time, its rotational drive is stopped. After this, the paper P is transferred to the relay roller pair 54.
During this time, the transport roller pairs 28 and 30 are rotated together with the movement of the paper P. Due to this co-rotation, the pair of conveyor rollers 28
Elastic energy in the direction of rotation is stored in the coil spring of the spring clutch 30 and 30 (the coil spring is slightly twisted). Then, as shown in Figure 3, the paper P
When the rotational drive of the relay roller pair 54 is stopped in a state where a part of the paper P is nipped by the transport roller pair 28, the accompanying rotation of the transport roller pair 28 is stopped (the trailing edge of the paper P is (at an upper position away from the transport roller pair 30).

When the co-rotation of the pair of conveyor rollers 28 is stopped, the elastic energy in the rotational direction stored in the spring clutch of the pair of conveyor rollers 28 (by the return of the coil spring of the spring clutch) causes the pair of conveyor rollers 28 and 30 is slightly reversed.

By reversing the transport roller pair 28 and 30, the sheet P nipped by the transport roller pair 28 is pulled back from the state shown in FIG. As a result, the deflection formed in the portion between the registration roller pair 58 and the relay roller pair 54 is eliminated.
In some cases, the leading edge of the paper P may come off the pair of registration rollers 58. This causes problems such as the paper P being fed in an inclined state from the pair of registration rollers 58 or the paper P not being fed from the pair of registration rollers 58, so that stable paper feeding is not performed.

Therefore, a main object of the present invention is to provide an improved paper feeding device that can prevent the above-mentioned conventional problems and provide stable paper feeding.

[Means to solve the problem]

In order to achieve the above main object, the present invention includes: a paper feed roller that feeds paper stored in a paper feed cassette; a pair of transport rollers that transport the paper fed from the paper feed roller;
a pair of relay rollers for sending the paper conveyed from the pair of conveyance rollers, a relay roller switch provided on the upstream side of the pair of relay rollers, a pair of registration rollers provided on the downstream side of the pair of relay rollers; a registration switch provided on the upstream side of the pair of registration rollers, the pair of transport rollers is connected to a drive source via a spring clutch, and after a predetermined period of time has elapsed from the ON operation of the relay roller switch, In a sheet feeding device whose rotational drive is stopped, and the relay roller pair is controlled so that its rotational drive is stopped after a predetermined time has elapsed from the ON operation of the registration switch, the conveyance roller pair is controlled to stop the rotational drive of the relay roller pair. The pair of sheets of paper are rotated for a predetermined period of time immediately before the rotational drive is stopped.
There is provided a paper feeding device characterized in that it is controlled to bend a portion located between the pair of relay rollers and the pair of transport rollers.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a paper feeding device improved according to the present invention will be described below with reference to FIGS. 1 and 2, with reference to the accompanying drawings. The paper feeding device shown in FIG. 2 has substantially the same configuration as that shown in FIG. 3 except for the control portion improved according to the present invention. Explanation will be omitted. Also, in the control timing of the paper feeding device, which is an embodiment of the present invention, shown in FIG. 1, substantially the same parts as in FIG. 4 are indicated by the same numbers, and explanations of the same parts will be omitted.

In the paper feeding device 1 (see FIG. 2) improved according to the present invention, the transport roller pairs 28 and 30 are rotated for a predetermined period of time immediately before the relay roller pair 54 stops rotating, and the paper This is characterized in that the portion located between the pair of relay rollers 54 and the pair of conveying rollers 28 is controlled to flex.

To explain specifically, as shown in FIGS. 1 and 2,
When the leading edge of the paper P sent by the middle m roller pair 54 reaches the registration switch 60, the registration switch 60 is turned to O.
It becomes N. 1 after the registration switch 60 is turned on
After 4 seconds, the rotational drive of the relay roller pair 540 is stopped.

The leading edge of the paper P stops moving while being blocked by the pair of registration rollers 58. A portion of the paper P located between the pair of registration rollers 58 and the pair of relay rollers 54 is bent.

The transport roller pairs 28 and 30 are driven to rotate for a predetermined period of 15 seconds from immediately before the rotation of the relay roller pair 54 stops, and are positioned between the relay roller pair 54 and the transport roller pair 28 on the paper P. It is controlled so that the part that bends is deflected. 'J2t! I indicates this state. During this 15 seconds, the conveyance roller pairs 28 and 30 are transferred to the relay roller pair 54.
It is rotated and driven. In this example, when the rotation of the relay roller pair 54 is stopped, the rotation of the transport roller pairs 28 and 30 is also stopped. As described above, the rotational speed of the pair of transport rollers 28 and 30 is set higher than that of the pair of relay rollers 54, so that the paper P is located between the pair of relay rollers 54 and the pair of transport rollers 28. A bend is formed in the part.

When the rotational drive of the transport roller pair 28 and 30 is stopped,
As mentioned above, due to the action of the coil spring of the spring clutch, the pair of conveying rollers 28 and 30 are slightly rotated in the opposite direction.
The paper P nipped by the transport roller pair 28 is pulled back. However, this amount of pulling back is sufficiently absorbed by the deflection formed in the portion of the paper P located between the pair of relay rollers 54 and the pair of transport rollers 28. Therefore, even if reverse rotation occurs in the transport roller pair 28 and 30, the registration roller pair 58 and the relay roller 5 of the paper P
It does not affect the deflection formed between 4 and 4.

Note that, as in the above embodiment, a plurality of paper feed cassettes and paper feed rollers (four each) are arranged to feed the paper P stored in the paper feed cassette, and the paper fed from the paper feed rollers is conveyed. In a paper feeding device in which a plurality of (four) conveyance roller pairs are arranged, at least the conveyance roller pair (the conveyance roller pair in the above embodiment) which is disposed closest to the relay roller pair among the plurality of conveyance roller pairs is (corresponding to roller pair 28) is
It is rotated for a predetermined period of time immediately before the rotation of the relay roller pair 54 stops, and the portion of the paper P located between the relay roller pair 54 and the pair of conveying rollers disposed closest to the relay roller pair is moved. It is controlled to make it waver.

〔Effect of the invention〕

According to the present invention described above based on implementation, the pair of conveying rollers is rotated for a predetermined period of time from immediately before the rotational drive of the relay roller stops, and the pair of conveying rollers is rotated for a predetermined period of time from immediately before the rotation drive of the relay roller is stopped, so that the pair of conveying rollers is rotated between the relay roller and the pair of conveying rollers. Since the positioning portion is controlled to be deflected, even if the conveyance roller pair reverses as described above and the paper is pulled back, it is sufficiently absorbed by the deflection of the paper, and the registration roller pair and relay roller pair The influence on the deflection between the two is reliably avoided.

Therefore, problems such as the paper being pulled back and the bending formed between the registration roller pair and the relay roller pair disappearing, and the leading edge of the paper coming off from the registration roller pair, are completely eliminated. , stable paper feeding is possible.

Although the present invention has been described in detail based on the embodiments above, the present invention is not limited to the embodiments described above, and various modifications and modifications can be made within the scope of the present invention.

For example, in the embodiment shown in FIG. 1, the rotational drive stop timing of the transport roller pairs 28 and 30 coincides with the rotational drive stop timing of the relay roller pair 54, but of course this is not limited to this. Relay roller pair 54
This holds true even after the rotational drive of . Furthermore, even if the rotational drive stop timing is before the rotational drive of the relay roller pair 54 is stopped, due to the difference in rotational speed between the conveyance roller pairs 28 and 30 and the relay roller pair 54, the relay roller pair 54 and the conveyance roller pair 28 This is true if the above-mentioned deflection is formed during this period.

In addition, although the number of paper feed cassettes, paper feed rollers, and pairs of transport rollers corresponding to these are four in the embodiment, the present invention can also be implemented with one paper feed cassette and one paper feed roller.

Furthermore, regarding the spring clutches of the pair of conveying rollers, in the embodiment, the pair of conveying rollers 28 and 30 are rotationally driven and controlled by a common spring clutch, and the pair of conveying rollers 32 and 34 are rotationally driven and controlled by another common spring clutch. However, a spring clutch may be provided for each pair of conveying rollers.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating control timing of a paper feeding device according to an embodiment of the present invention. 21st! I am the 11th! FIG. 3 is a schematic cross-sectional view showing an operation mode of the paper feeding device according to the control timing of I. FIG. 3 is a schematic cross-sectional view showing how a conventional paper feeding device operates. FIG. 4 is a diagram illustrating control timing of the paper feeding device shown in FIG. 3. 1... Paper feed devices 12 to 18... Paper feed cassettes 20 to 26... Paper feed rollers 28 to 34... Conveyance roller pair 31... Conveyance switch 54... ... Relay roller pair 55 ... Relay roller switch 58 ... Registration roller pair 60 ... Registration switch

Claims (1)

[Claims] 1. A paper feed roller that feeds the paper stored in the paper feed cassette, a pair of transport rollers that transports the paper sent from the paper feed roller, and a pair of transport rollers that transport the paper that is transported from the pair of transport rollers. A pair of relay rollers for feeding the paper, a relay roller switch provided upstream of the pair of relay rollers, a pair of registration rollers provided downstream of the pair of relay rollers, and a pair of registration rollers provided upstream of the pair of registration rollers. The transport roller pair is connected to a drive source via a spring clutch, and after a predetermined period of time has elapsed since the relay roller switch is turned on, the rotational drive thereof is stopped and the relay roller pair is connected to a drive source via a spring clutch. In a sheet feeding device whose rotational drive is controlled to be stopped after a predetermined period of time has elapsed from the ON operation of the registration switch, the transport roller pair is rotated from just before the rotational drive of the relay roller pair is stopped. The paper is rotated for only a period of time.
A paper feeding device characterized in that it is controlled to bend a portion located between the pair of relay rollers and the pair of conveying rollers. 2. A plurality of paper feed cassettes and a plurality of paper feed rollers that transport the paper stored in the paper feed cassette are arranged, and a plurality of transport roller pairs that transport the paper sent from the paper feed rollers. out of the plurality of conveyance roller pairs, at least the conveyance roller pair disposed closest to the relay roller pair is activated for a predetermined period of time immediately before the rotational drive of the relay roller pair is stopped. Claim 1, wherein the paper is controlled to be rotationally driven to deflect a portion of the paper located between the pair of relay rollers and the pair of conveyance rollers disposed closest to the pair of relay rollers. Paper feed device as described.