JPS63171745A - Sheet conveying method - Google Patents

Abstract

PURPOSE:To correct a sheet position without entailing any rumples, by conveying a sheet as correcting its position by a resist roller pair travelable in the axial direction after forming the specified quantity of deflection in the sheet at the time of conveyance of the sheet in multi-copying. CONSTITUTION:A sheet S being refed by a conveyor roller pair for receiving multi-copying or duplex copying, coming into contact with a resist roller pair 30 and formed with the specified quantity of deflection L1, is inserted into a contact part of these paired resist rollers 30 the tip by restoring force to be produced by the deflection. In succession, after an edge of the sheet S is held between these paired resist rollers 30 rotating as long as the specified time, deflection L2 larger than the last deflection quantity is formed in the sheet S by rotation of the conveyor roller pair, thus preparations for correcting the misregistration take place. And, the resist roller pair 30 and the conveyor roller pair are synchronously rotated, and the resist roller pair 30 is moved in the axial direction as conveying the sheet in the state that the deflection is formed in th sheet S, whereby its positioning in a rectangular direction is carried out without giving excessive force to the sheet S.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention relates to a sheet conveying method in an image forming apparatus such as a copying machine or a laser beam printer. The present invention relates to a sheet conveyance method for conveying a sheet while correcting the position of the sheet.

(b) Conventional technology - In an image forming apparatus, in order to transfer an image to an accurate position on a sheet, the sheet is conveyed while correcting its position. This correction work is important in so-called multiple copying in which copies are made multiple times.

Therefore, the present applicant has previously devised a sheet conveyance device in which a pair of registration rollers is movable in the axial direction, as a conveyance device that can accurately correct the position of a sheet. In this conveyance device, a sheet is fed from a pair of conveyance rollers provided on the upstream side toward a pair of registration rollers that are stopped, and the sheet is bent by a predetermined amount while the leading edge of the sheet is in contact with the contact portion of the pair of registration rollers. That is, a loop is formed to align the leading edge of the sheet (vertical registration alignment), and the conveying roller pair is stopped. Then, the pair of conveyor rollers is rotated again, and at the same time the pair of registration rollers is rotated so that the sheet is conveyed while forming a loop and is positioned at an accurate position perpendicular to the conveyance direction (tank registration). 2), and is configured to move the pair of registration rollers in the axial direction.

→ Problems to be Solved by the Invention By the way, the above-mentioned conveying device has a configuration in which, as described above, a loop of sea 1- is formed in the pair of manufacturing rollers and the pair of registration rollers, and only the pair of registration rollers is moved in the axial direction. Therefore, if the loop of the sheet is too small, when the pair of registration rollers moves in the axial direction to correct the position, an unreasonable force is applied to the sheet, causing wrinkles. On the other hand, if the loop is too large, as shown in FIG. If this happens, not only the position in the direction perpendicular to the sheet conveyance direction (horizontal registration alignment) cannot be corrected, but also the longitudinal registration alignment of the sheet becomes impossible. In other words, it is necessary to form large loops in order to prevent wrinkles from forming on the sheets when aligning the sheets in the tank, but when aligning the sheets vertically, the smaller the loops, the better. There was a problem.

(b) Means for solving the problem The present invention aims to solve the above-mentioned problems,
A pair of registration rollers that can move in the axial direction of the rollers allows
When conveying a sheet by correcting its position in the direction perpendicular to the sheet conveyance direction, the sheet to be conveyed is first brought into contact with the contact portion of the stopped pair of registration rollers to form a predetermined amount of deflection in the sheet, and then After rotating the pair of registration rollers to sandwich the tip of the sheet between the pair of registration rollers, the pair of registration rollers is stopped again, and then a deflection larger than the predetermined amount of deflection is formed in the sheet. ,
The present invention is characterized in that the pair of registration rollers is moved in the axial direction to correct the position of the sheet while conveying it.

(E) Effect By employing the above means, the sheet is transported by the transport roller pair and comes into contact with the registration roller pair to form a predetermined amount of deflection. It fits into the contact part of the roller pair. Subsequently, after the leading edge of the sheet is clamped and fixed by a pair of registration rollers that rotate for a certain period of time, a deflection greater than the previous deflection is formed on the sheet due to the rotation of a pair of transport rollers, and the sheet is deflected in a direction perpendicular to the feed direction. Preparations are made to correct the misalignment. Then, the pair of registration rollers and the pair of conveyance rollers rotate in synchronization, and the pair of registration rollers is moved in the axial direction while conveying the sheet with the above-mentioned flexure, and the pair of registration rollers is moved in the conveyance direction without applying excessive force to the sheet. Positioning is performed in the perpendicular direction.

(F) Embodiments Below, embodiments embodying the present invention will be described with reference to the drawings.

A copying apparatus 1 configured to perform multiple copies or double-sided copies on the same transfer sheet has a configuration as shown in FIG. It has 3.

The main body 3 of the apparatus includes a document mounting table 4, a light source 5, and a lens system 6.2.
The copying section 2 is provided with cassettes 7a, 7b, etc., and the copying section 2, which includes a cylindrical photoreceptor 8, etc., is disposed approximately at the center of the main body 3 of the apparatus. Near the periphery of the photoreceptor 8, two developing units 9a and 9b each containing toner of a different color can be set and reset by moving in the direction of the arrow so that copies can be made in a desired color. Further, on the downstream side in the rotational direction of the photoconductor 8, a transfer charger "ulo" and a separation charger 11, a cleaner 12, and a secondary phase charger 13 are arranged. Paper feed rollers 14a and 14b are disposed, and the transfer sheet S is guided to a pair of registration rollers 17 via a pair of transport rollers 15a and 15b and paths 16a and 16b, respectively, and is arranged below the main body 3 of the apparatus. A transfer sheet S to be subjected to multiple copies or double-sided copies is guided to the pair of registration rollers 17 via a sheet conveying section 19 provided. A fixing device 20 is disposed at the rear side of the fixing device 20, and a first ejection roller pair 21 normally transfers the transfer sheet via a second ejection roller pair 22 to a tray, etc. outside the machine. A flapper 23 and an auxiliary flapper 24 are arranged between the first pair of discharge rollers 21 and the second pair of discharge rollers 22. The transfer sheet S discharged from the discharge roller pair 21 is conveyed along the upper side of the flapper 23 at the solid line position, and the conveyance force causes the auxiliary flapper 24 to swing in the direction of the arrow, and based on this, the detection arm 25 detects the optical sensor 26.
is operated to detect the passage of the transfer sheet, and the transfer sheet is discharged to the outside of the machine by a second pair of discharge rollers 22 which rotate normally. On the other hand, during double-sided copying, the transfer sheet S is partially removed from the machine by normal rotation of the fa2 ejection roller pair 22, as in the normal case described above. However, when the rear end of the transfer sheet leaves the auxiliary flapper 24, the detection arm 25 and the optical sensor 26 operate to drive the second discharge roller pair 22 in the reverse direction. It is designed to be guided by the left side of the flapper 24 and the flapper 23 and introduced into the path 27. Therefore, during double-sided copying, the second discharge roller pair 22, the detection arm 25, the optical sensor 26, and the path 27
The transfer sheet is fed again. In addition, when performing multiple copying, the flapper 23 is switched to the dotted line position and the first
Transfer sheet S discharged from the discharge roller pair 21
is the path 27 due to the guide action of the right side of the flapper 23.
It is designed to be introduced directly into Therefore, during multiple copying, the transfer sheet is re-fed by the first discharge roller pair 21, the flapper 23, and the path 27.

Then, the transfer sheet S introduced into the path 27 is transferred to the transport roller pair 28, 29 and the transfer sheet in the lateral direction -(lI
The sheet is guided by the pair of registration rollers 17 via a sheet transporting section 19 having a pair of registration rollers 30 that is configured to be movable in the axial direction in order to align the ends of the sheet 11 with reference positions.

The pair of registration rollers 30 for correcting the position M in the direction perpendicular to the sheet conveyance direction has a configuration as shown in FIGS. 3 and 4, with upper rollers 30 pressed against each other.
a and a lower roller 30b. The upper roller 30a is rotatably supported by the shaft 31a, and is integrally fixed to the lower roller 30b (the shaft 31b), and the shaft 31a of the upper roller 30a and the lower roller 30
The shafts 31b of b are rotatably and slidably supported on the front and rear side plates of the copying apparatus main body 3 via bearings 32a, 32b, respectively, and the shafts 31a, 31
It is biased to the left in FIG. 4 by a spring 35 disposed between the collar 33 and the collars 33 and 33 disposed on the upper surface of the collar 33.

Further, the shaft 31a and the shaft 31b are each connected to a block body 36.
The block body 36 is pushed through so that it can only rotate freely, and the block body 36 is brought into contact with a cam member 37 via a roller member 36a disposed at an upper portion thereof. The cam member 37 is of a type in which an inclined cam is formed on the circumference of the end of a cylindrical body, and when the spring clutch 39 is turned on by a solenoid (not shown), the rotational force of the drive gear 40 is transferred to the clutch. 39 to the shaft 41 to rotate the cam member 37, and one rotation of the cam member causes the upper roller 30a and the lower roller 30b to move against the spring 35 through the block body 36. The cam member 37 is moved in the left and right A1 right direction (see FIG. 3), and under normal conditions, the cam member 37 is
A central portion 37a of the inclined surface is brought into contact with the roller member 36a, and the upper roller 30a and lower roller 30b are stopped at the center position of the left-right movement stroke, that is, the home position. Also, a gear 44 is attached to the shaft 31b of the lower roller 30b.
is fixedly installed, and when the electromagnetic clutch 45 is turned on, the rotational force of the drive gear 46 is transmitted to the shaft 47 via the clutch 45.
As the transmission gear 48 is rotated, the gear 44 that meshes with the gear 48 is rotated, and the lower roller 30b is thereby rotated, so that the tip is brought into contact with the upper roller 30a and the lower roller 30b. The transfer sheet S, which had stopped due to the contact, is now subjected to the conveyance action. Furthermore, as shown in FIG. 3, an optical sensor 49 is disposed close to the contact portion between the upper roller 30a and the lower roller 30b, and the optical sensor 49 detects one side edge of the transfer sheet. is now being detected. 3 is an upper guide plate for guiding the transfer sheet S toward the contact portion between the upper roller 30a and the lower roller 30b, and is designated by the reference numeral 50 in FIG. The shaft 31a is integrally fixed to the shaft 31a.

In the copying apparatus 1 as described above, in this embodiment, the copying section 2 and the fixing device 204! The transferred sheet that has been carried out is re-fed to undergo double-sided copying or multiple copying, and is fed like raw coal passing through the sheet conveying section 19.

When the transferred sheet S passes through the pair of conveying rollers 28 and 29 of the sheet conveying section 19 and is conveyed to the pair of registration rollers 30 as shown by arrow C in FIG. The passage of the transfer sheet S is detected just before , and based on this, even after the leading edge of the transfer sheet comes into contact with the contact portion of the stopped upper roller 30a and lower roller 30b, the conveyance roller pair 29 continues to move the transfer sheet S for a predetermined period of time. The conveying action is continued, and after the predetermined time has elapsed, the conveying operation of the double feed roller pair 29 is stopped, so that the leading edge of the transfer sheet is in contact with the contact portion of the upper roller 30a and the lower roller 30b as shown in FIG. (As shown in aJ, a loop consisting of a predetermined amount of deflection Ll is formed on the transfer sheet.

At this time, vertical registration alignment and skew correction of the transfer sheet S are performed. As shown in Figure 5, the amount of deflection of the transfer sheet refers to the distance between the tip of the transfer sheet and the roller pair when the loop formed at the contact part of the roller pair is bent as shown by the dashed line in the figure. The amount of deflection L1 is defined as the distance from the contact portion of
The amount is set so that it enters the contact area of b. Next, the electromagnetic clutch 45 is turned on for a short time, whereby the rotation of the drive gear 46 is transmitted to the gear 44 via the shaft 47 and the gear 48, and the lower roller 30b rotates by a small amount, as shown in FIG.
As shown in b), the tip of the transfer sheet 1-3 touches the upper roller 30.
a and the lower roller 30b. Thereafter, the conveyance roller pair 29 is rotated by a predetermined amount again to form a large deflection L2 on the transfer sheet S that satisfies the condition L2>L as shown in FIG. 1 (C1), and the conveyance roller pair 29 is stopped again. After that, the pair of transport rollers 29 is rotated again and again, and at the same time, the electromagnetic clutch 45 is turned on again to rotate the pair of registration rollers 30, and the transfer sheet S is transported while forming a loop with the deflection amount L2. At the same time, the spring clutch 39 is turned on and the drive gear 4 is turned on.
0 rotation is transmitted to the cam member 37 via the shaft 41, and the rotation of the cam member 37 moves the block body 36 from its stop position, that is, the home position, through the roller member 36a.
The transfer sheet S is transported in a direction perpendicular to the transport direction, and its position is corrected based on the signal from the optical sensor 49. At this time, due to the existence of the loop formed by the large amount of deflection L2 described above, the lateral movement of the transfer sheet S is performed smoothly without applying any unreasonable force or deforming the transfer sheet S.

In the above embodiment, the pair of axially movable registration rollers 30 is provided in the sheet conveying section 19 for refeeding the sheet to the copying section 2, but it is not necessary to be limited to such a location. , the pair of registration rollers 17 having such a configuration can be provided at any location, and the present method can be applied to a pair of registration rollers that are provided at any location and are movable in the axial direction. reactor. After forming a large amount of deflection L2 on the sheet, the registration roller pair 30 is rotated and at the same time the roller pair 30 is moved in the axial direction, and while the transfer sheet is being fed, the registration roller pair 30 is moved in the direction perpendicular to the conveying direction. The position is corrected by first moving only the pair of registration rollers 30 in the axial direction to correct the position in the direction perpendicular to the continuous feeding direction, and then rotating the pair of registration rollers 30. It is also possible to convey the transfer sheet S by using the transfer sheet S.

(g) As described in detail, according to the present invention, when a sheet is guided by correcting its position in the direction perpendicular to the sheet conveyance direction, by a pair of registration rollers that are movable in the axial direction of the rollers. , the sheet to be conveyed is brought into contact with the contact portion of the stopped pair of registration rollers to form a predetermined amount of deflection on the sheet, and then the pair of registration rollers is rotated to sandwich the leading edge of the sheet between the pair of registration rollers, and then the sheet is pressed again. After stopping the pair of registration rollers, and then forming a deflection larger than the predetermined amount on the sheet, moving the pair of registration rollers in the axial direction to correct the position in the direction perpendicular to the conveyance direction of the sheet. This allows the sheet to be conveyed without applying excessive force and causing wrinkles (position correction in the direction perpendicular to the conveyance direction (horizontal registration alignment) and vertical registration alignment of the sheet can be carried out at the same time. can do.

[Brief explanation of the drawing]

FIG. 1 (al to fel are explanatory diagrams showing one embodiment of the sheet tR feeding method according to the present invention, FIG. 2 is a configuration diagram of an image forming apparatus, and FIG. 3 is a perspective view showing the configuration of a pair of registration rollers, Figure 4 is a cross-sectional view of the same, Figure 5 is an explanatory diagram of the amount of sheet deflection, and Figure 6 is an explanatory diagram of the amount of sheet deflection.
The figure is an explanatory diagram of a conventional conveyance method. S... sheet (transfer sheet), L, -FF fixed amount of deflection, L2... greater deflection than a predetermined amount of deflection, 1
... Image forming device (W, ear device f), 2... Copying section, 19... Sheet return section, 20... Fixing device
, 28.29... Conveyance roller pair, 30... Registration roller pair movable in the axial direction, 30a, upper roller, 30b... lower roller.

Claims (1)

[Claims] (1) In an image forming apparatus that transports a sheet by correcting its position in the direction perpendicular to the sheet transport direction using a pair of registration rollers that are movable in the axial direction of the rollers, the sheet is transported to the contact portion of the pair of registration rollers that are stopped. Abutting the sheet to form a predetermined amount of deflection on the sheet, then rotating the pair of registration rollers to sandwich the tip of the sheet between the pair of registration rollers, stopping the pair of registration rollers again, and then The sheet is characterized in that, after forming a deflection larger than the predetermined amount of deflection on the sheet, the pair of registration rollers is moved in an axial direction to correct the position of the sheet in a direction perpendicular to the conveying direction of the sheet, and then the sheet is conveyed. Transportation method.