JPS61243751A - Paper feeder - Google Patents

Abstract

PURPOSE:To prevent load applied to a resist roller from change according to passage for stabilizing roller transfer by providing a relay roller including a drive system for feeding paper with the same speed as a paper feed section and speed equal to imaging process speed. CONSTITUTION:While a resist roller 18 sends paper, a relay roller 16 is rotated by a separate drive with same speed as the resist roller 8 to hold the flexion of paper formed in a buffer 13 for a certain time at every size of paper. And a paper feed roller 8, relay rollers 17, 16 in a paper feed section 4 are sequential ly driven to form the flexion of paper in the buffer 13 and temporarily stopped. Here, while same applies to the paper section 4, the drive of paper feed rollers 7, 8 is stopped when the end of paper reaches the relay rollers 16, 17 in the nearest downstream side. Next, while the resist roller 18 sends the paper, the relay rollers 16, 17 are rotated with the same speed as the roller 18 according to the size of paper to form a proper flexion in a portion of a buffer 13. Thus, drive load on the resist roller at every paper feed section is uniformed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a paper feeding device in a copying machine, a printing machine, etc., and particularly relates to a drive control mechanism for a relay roller provided at an intermediate position depending on the length of a conveyance path. .

Conventional technology Length of conveyance path from paper feed section to registration roller 75
7. When the length is long, it is common practice to provide a relay roller in the middle.

In this case, the fed paper is fed one by one from the paper feed section, the leading edge of the paper is held in the relay roller, the relay roller conveys the paper to the nip of the registration roller, and the paper is bent and driven. Stop.

Conventionally, even when the registration rollers were driven in synchronization with the image on the photoreceptor, the relay rollers stopped driving, and the trailing edge of the paper was conveyed while slipping against the relay rollers. . Therefore, the driving load on the registration rollers becomes large, which hinders the stabilization of roller conveyance. Further, there has been no one that takes into consideration the processing speed of the image forming system when driving the relay roller.

1. The present invention aims to eliminate the drawbacks of the above-mentioned conventional examples and provide a paper feeding device that can stabilize roller conveyance.

Structure For this purpose, the present invention provides a relay roller having both a drive system for feeding paper at approximately the same speed as the paper feed section and a drive system for feeding the paper at a speed equal to the speed of the image forming process. This is what I did.

Next, the present invention will be explained based on one example.

FIG. 1 is a schematic diagram of the paper feed section, and shows 1, 2, 3, 4
are paper feeding units arranged vertically, and 5, 6, 7.8 are paper feeding rollers. These paper feed rollers 5, 6, 7.8 feed the paper one sheet at a time from above each paper bundle 9.

Further, buffers 13 and 14 corresponding to the deflection of the paper are formed by guide plates shown at 10, 11, 12 and 15.20° 21, respectively. The middle go roller 16 is located between the registration roller 18 and the paper feed roller 7, and the relay roller 17 is similarly located between the relay roller 16 and the paper feed roller 8. Paper size detection is performed within each paper feed unit (Sf in the figure). A paper detection sensor 19 is installed near the upstream side of the registration roller 18.

Next, the operation will be explained along the flow of the paper.

In the paper feed section 1, a paper feed roller 5 feeds out one sheet of paper.

When the leading edge of the paper is detected by the paper detection sensor 19, the paper feeding roller 5 is driven for a certain period of time (by a pulse signal or the like), and then the driving of the paper feeding roller 5 is stopped. At this time, the registration rollers 18 are stopped, the leading edge of the paper hits the nip and the nip of the registration roller 18, a predetermined deflection is created in the buffer 13, the paper is straightened such as skinny paper, and the paper is placed in the nip of the roller. Insert the tip completely in your mouth to improve the conveyance of the registration roller.

Next, the registration rollers 18 are driven in synchronization with the image forming system, and feed the paper into the image forming system so that the image is placed on a predetermined position. The paper feed section 2 is also similar to the paper feed section 1. In the paper feed section 3, the paper feed roller 7 and the relay roller 16 are driven by the paper feed command, and as described above, the paper is fed until a predetermined deflection is achieved, and then the drive is temporarily stopped.

Next, while the registration roller 18 is feeding the paper, the relay roller 16 is rotated at the same speed as the registration roller for a certain period of time for each paper size by a separate drive, so that the paper sag formed in the buffer 13 does not disappear. . In paper feed section 4, paper feed roller 8
, the relay rollers 17 and 16 are sequentially driven, and as described above, the paper is deflected in the buffer 13 and then temporarily stopped. At this time, the same applies to the paper feed unit manually, but the paper feed roller 7.8 is set at the time required for the leading edge of the paper to reach the relay rollers 16 and 17 located on the nearest downstream side (including time delays due to slips, etc.). At this point, stop the drive of paper feed rollers 7 and 8 (if the paper is small, this will prevent the next paper from being fed out).
. Next, while the registration roller 18 is feeding the paper, the relay rollers 16 and 17 are rotated at the same speed as the registration roller 18 depending on the paper size, so that an appropriate amount of deflection is formed in the buffer 13 portion. .

In this way, the load applied to the registration rollers 18 is prevented from changing greatly depending on the conveying path, and the driving load of the registration rollers for each sheet feeding section is made uniform. As a result, the conveyance performance of the registration rollers 18 is stabilized (slip is constant), so that the vertical magnification of each sheet feeding section is averaged.

Furthermore, even if the path between the paper feed roller and the registration roller is long, by increasing the linear speed of the paper feed roller and the relay roller, the same first copy time as the paper feed section with a short path can be achieved.

Figures 2, 3, and 4 show paper feed section 1 (2), paper feed section 3,
FIG. 3(a) is a diagram showing a state in which paper is fed out from the paper feed unit 4;
(b) shows the state in which the registration rollers are deflected and the registration rollers are driven. Further, FIG. 5 is a timing chart in the paper feed section 4.

Next, the drive system for the relay rollers 16 and 17 will be explained based on FIG.

Electromagnetic clutches 22, 23, and 24 each having a gear are attached to the registration roller 18 and relay rollers 16, 17, respectively. Each clutch is connected to the main body 1 drive system (not shown), and the registration rollers 18 transport the paper at the same speed as the image forming process. In addition, relay rollers 16, 17
transports paper at the same speed as the paper feed mechanism (paper feed roller). When the registration roller 18 rotates, the electromagnetic clutch 22 is turned on and the gear 22a rotates in the direction of the arrow. At this time, the relay rollers 16 and 17 are equipped with a gear 26.
28 is driven by the gear 22a by the idle gears 25 and 27, and each of the four relay rollers 16, 17 rotates in the direction of the arrow at the same speed as the registration roller 18.

FIG. 7 is a schematic diagram of a one-way clutch with gears 26 and 28. As can be seen from this figure, when the electromagnetic clutch 23 or 24 is turned on, the shaft rotates in the direction of the dotted arrow, and the relay roller rotates. At this time, since the one-way clutch 29 is in the open direction, the gear 26 or 28 is not driven, and the registration roller 18 can be maintained in a standby state. Next, when the registration roller 18 begins to rotate by the electromagnetic clutch 22, the relay rollers 16 and 17 rotate through their respective gears, and the gears 26 and 28 rotate in the direction of the solid line arrow in FIG. Lock and rotate the relay rollers 16,17. At this time, since the electromagnetic clutches 23 and 24 are in the OFF state, each of the relay rollers 16 and 17 transports the paper at the same speed as the registration roller, that is, at the same speed as the image forming system process speed.

There are various driving methods; in the embodiment, registration rollers were driven, but the relay rollers may be driven directly from the main body, or a separate motor may be used to drive the relay rollers.

Effects As described above, since the present invention controls the drive of the registration roller and relay roller, the conveyance performance is stabilized, and the vertical magnification error of copying does not change from paper feeding section to paper feeding section. Another effect is that the difference in first copy time due to the length of the path between the paper feed roller and the registration roller is eliminated.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a paper feeding section according to an embodiment of the present invention, and FIG.
Figures 3 and 4 are diagrams showing different paper conveyance states of the paper feed section, respectively, (a) the paper is in a bent state, (b)
5 is a diagram showing the driving timing of each member in the paper feed section 4, FIG. 6 is a diagram showing the drive system of the relay roller, and FIG. 7 is a diagram showing the one-way clutch of the gear. FIG.

Claims (1)

[Claims] In a paper feeding device of a copying machine, a printing machine, etc., a registration roller that feeds intermittently in synchronization with the image forming process to align the image position and the paper position, and to correct the leading edge position and curvature of the paper; Depending on the paper detection sensor located near the upstream side of the registration rollers, the paper feed section that feeds paper sheet by sheet from the stack at a speed faster than the process speed, and the conveyance length between the registration rollers and the paper feed section, One or more relay rollers installed in the middle and having both a drive system that feeds paper at approximately the same speed as the paper feed section and a drive system that feeds paper at a speed that is equal to the process speed of the image forming system, and near the upstream side of the registration roller. A paper feeding device equipped with a paper guide section that has a space for the deflection of the paper.