JP2000280554A - Paper feeding device for image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise quality of an image on a recording medium by correcting a shift of the recording paper. SOLUTION: This paper feeding device comprises a detection means 206 for detecting a shift of a recording paper in the width direction perpendicular to the feeding direction of the recording paper 204, a side resist roller 202 which nips the recording paper and moves in the width direction during the feeding of the recording paper, means 210, 501, 502 for driving the side resist roller to move in the width direction in accordance with a signal corresponding to the shift detected by the detection means and a feeding roller that feeds the recording paper from the side resist roller to the downstream side. It further comprises a recording paper shift correcting control means for the side resist roller that controls a paper feeding speed and/or a moving speed of the side resist roller and finishes the correction of the shift of the recording paper before the top of the recording paper reaches the other feeding roller when the moving amount of the side resist roller in the width direction exceeds a predetermined level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in a copying machine, a printer, a facsimile, etc., having a function of correcting a shift amount of an image and a recording sheet in a direction perpendicular to a paper feeding direction. .

[0002]

2. Description of the Related Art Conventionally, in various image forming apparatuses,
There is a paper feeder provided with a paper feeder having a function of correcting a paper misalignment direction in a direction orthogonal to the paper feed direction. In such an image forming apparatus, generally, a means for detecting one end position of a width in a direction orthogonal to a paper feeding direction of a recording sheet to be conveyed, and a detecting means for nipping the recording sheet and conveying the recording sheet during conveyance. And a driving means for driving the lateral registration roller to move in the width direction based on a signal of the horizontal registration roller. The speed and the speed at the time of laterally moving in the width direction to correct the deviation in the width direction are set to a constant speed.

[0003] That is, the lateral movement for correcting the amount of displacement in the width direction of the lateral registration roller is carried out by holding the leading end of the recording paper between a pair of rollers of the lateral registration roller, and then moving the leading end of the recording paper downstream. Since it must be completed before being caught by a certain roller, the lateral movement speed is set to a value suitable for that.

[0004]

However, in some cases, the amount of deviation of the recording paper in the width direction exceeds the predetermined amount and becomes exceptionally large. In this case, another pair of recording paper whose downstream end is located downstream is used. In some cases, the correction operation cannot be completed before the rollers reach the first roller, and therefore, there is a problem that the quality of image formation on recording paper is not guaranteed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and comprises an upstream horizontal registration roller and a downstream roller even if the amount of displacement of a recording sheet in the width direction in an image forming apparatus is large. It is an object of the present invention to provide an image forming apparatus in which the deviation of a recording sheet between two sheet feeding rollers is preferably corrected to improve the image quality of the recording sheet.

[0006]

In order to achieve the above object, an image forming apparatus according to the present invention detects a deviation in a width direction of a recording sheet conveyed in a direction orthogonal to a conveying direction of the recording sheet conveyed. Means, while nipping and transporting the recording paper, and a lateral registration roller for laterally moving in the width direction during transportation to correct a position in the width direction of the recording paper; and Means for driving to move laterally in the width direction based on a signal corresponding to the deviation of
When another conveyance roller provided so as to convey the recording paper sent from the lateral registration roller further downstream and the means for detecting the deviation of the recording paper have detected a deviation amount exceeding a predetermined amount. Before the leading end of the recording paper reaches the main registration roller, a recording paper misalignment correction control means for adjusting the paper feed speed or the lateral movement speed of the lateral registration roller to end the correction by the lateral movement. Have.

In the paper feeder of the image forming apparatus, the shift correction control means for moving the lateral registration roller, when detecting that the moving amount of the lateral registration roller exceeds a predetermined amount, in the width direction of the lateral registration roller. The lateral movement speed of the recording paper is increased, and the movement of the recording paper in the width direction is completed before the leading end of the recording paper reaches another transport roller.

When the deviation correction control means for the recording paper detects that the lateral movement amount of the lateral registration roller exceeds a predetermined amount, it lowers the paper feed speed of the lateral registration roller,
Before the leading edge of the recording paper reaches another transport roller, the movement of the recording paper in the width direction can be completed.

When the deviation correction control means for the recording paper detects that the lateral movement amount of the lateral registration roller exceeds a predetermined amount, it lowers the paper feed speed of the lateral registration roller, and reduces the paper feed speed in the width direction of the recording paper. By increasing the moving speed, it is possible to finish the movement of the recording paper in the width direction before the leading end of the recording paper reaches another transport roller.

[0010] The horizontal registration roller in the image forming apparatus can be disposed at an exit of a double-sided refeeding section.

Further, the other transport roller in the image forming apparatus can be a main registration roller for discharging the recording paper toward the transfer section.

[0012]

In the image forming apparatus having the above structure, the detection by the detecting means for detecting one end position of the width in the direction orthogonal to the conveying direction of the recording paper to be conveyed,
The lateral registration roller, which horizontally moves in the width direction of the recording paper while nipping and transporting the recording paper, can be moved by the driving unit while the recording paper is being transported. If the detection means detects that the movement amount exceeds a predetermined amount, the paper feed speed of the lateral registration roller may be reduced to extend the time until the leading edge of the recording paper reaches another pair of rollers. it can. The correcting operation of the lateral registration rollers is completed so as to correct the recording paper that has deviated within the extended time, and the recording paper is returned to a normal state, thereby performing highly accurate paper feeding. Quality images can be obtained.

When it is detected that the amount of movement of the lateral registration roller exceeds a predetermined amount, the lateral movement speed of the lateral registration roller in the width direction of the recording paper is increased so that the leading end of the recording paper reaches another conveyance roller. Even if the correction operation is completed before the completion, the above object can be achieved without changing the time until the recording paper reaches the next transport roller.

Furthermore, in order to achieve the same object, when it is detected that the amount of lateral movement of the lateral registration roller exceeds a predetermined amount, the lateral movement speed of the lateral registration roller in the width direction of the recording paper is not changed. Even if the paper feed speed of the horizontal registration rollers is reduced, the lateral movement of the recording paper in the width direction can be completed before the leading end of the recording paper reaches another conveyance roller. Paper feeding with high precision can be performed.

Further, in order to achieve the same object, when it is detected that the moving amount of the lateral registration roller exceeds a predetermined amount, the moving speed of the lateral registration roller in the width direction of the recording paper is increased, and the lateral registration roller is moved. Even by lowering the paper feed speed of the roller, the widthwise movement of the recording paper can be completed before the leading end of the recording paper reaches another transport roller, so that the recording paper can be moved to another downstream transport roller. And the time for correcting the misalignment is shortened, so that accurate paper feeding can be performed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, as an image forming apparatus provided with a paper feeding device according to the present invention, an outline will be described using an electrophotographic copying machine as an example.

As shown in FIGS. 1 and 2, the electrophotographic copying machine 10 is provided with an original glass table 13 on the upper surface of the main body of the apparatus. A scanner (scanning optical device) 134 that constitutes an image reading unit is provided in the portion. The scanner 134 has an illumination lamp (light source) 132 for illuminating the scanning light on the document 2 on the document glass table 13, and transmits the reflected light from the document 2 onto a photosensitive drum 126 as an image carrier described later. It has a projection lens 138 for guiding and reflection mirrors 140 and 142.

Although the original glass table 13 is not shown,
A document supply device may be provided to be able to open and close so as to cover the document glass table 13. The document supply device includes a document feeder for a flow reading (sheet through) in which the illumination lamp 132 is stopped at a predetermined position and the document 2 is read while being transported, and an illumination lamp which stops the document at a predetermined position. An automatic document feeder that performs reading while moving the 132 may be provided.

On the lower side of the scanner 134,
The photosensitive drum 126 is provided so as to rotate clockwise. Around the photosensitive drum 126, a primary charger 154 that uniformly charges the photosensitive drum 126, and supplies toner to an electrostatic latent image formed on the photosensitive drum 126 by exposing the light reflected from the scanner 134 to light. And a transfer charger 128 for transferring the toner image on the photosensitive drum 126 disposed in the middle of the paper transport path to the recording paper 1, and for separating the transferred recording paper 1. Separation charger 160, photosensitive drum 1 after transfer
A cleaning device (not shown) that removes, collects, and discharges the toner remaining on the photosensitive drum 26 is sequentially arranged along the rotation driving direction of the photosensitive drum 126.

Further, the toner image on the recording paper 1 is adiabatically provided at the exit side end of a belt-shaped paper conveyance path 162 extending from the transfer charger 128 and the separation charger 160 toward the exit of the apparatus main body. Fixing device 164 for fixing
Are arranged, and from the exit of the fixing device 164,
The paper discharge conveyance path extends toward the paper discharge tray 26 mounted at the outlet of the apparatus main body.

In this paper discharge conveyance path, a first paper discharge roller 169 is disposed near the exit of the fixing device 164, and a second paper discharge roller is disposed near the exit of the apparatus main body. The recording paper is conveyed toward the discharge tray 26 by the rotational driving force of each of these rollers. A paper discharge sensor 174 for monitoring the paper conveyance state is provided near the first paper discharge roller 169.
Is arranged.

The belt-shaped paper transport path 162
Below the lower part, a lower transport unit 1 that constitutes a main part of the
76 is provided below the lower transport unit 176. The paper feed cassette 1 stores cut recording paper for each size.
8 and 20 are provided so as to form a two-stage paper feed unit. The detailed configuration and operation of the above-described tiled device will be described later.

At the outlet on the right side in the drawing of the paper feed cassettes 18 and 20, a paper feed roller 112 for feeding out the recording paper placed on the paper feed cassettes 18 and 20 is arranged respectively. Paper cassettes 18, 20
The transport paths extend toward the transfer area of the photosensitive drum 126 of the sheet feeding roller 112 of the first embodiment. Each of these transport paths merges into one transport path, and a main registration roller 122 that feeds the recording paper to the transfer area in synchronization with the image forming process is provided near the transfer area in the merged transport path. Have been. Further, a registration sensor 124 for monitoring the paper carrying state is disposed upstream of the main registration roller 122 in the transport direction, as shown in FIG.

As shown in FIG. 2, a manual feed tray 22 is attached to a side of the apparatus main body opposite to the paper discharge tray 26 so as to project obliquely upward from the main body. The manual feed tray 2 is provided at the lower end exit of the manual feed tray 22.
A manual paper feed roller for feeding recording paper of an arbitrary size placed on the paper feed roller 2 is arranged, and a manual paper feed path 21 extends from the manual paper feed roller toward the transfer area. The distal end portion of the manual feed path 21 is connected to be connected to the above-described convey path 17 to the main registration roller 122.

Next, the tile stacking device will be described. The paper discharge transport path branches at a position upstream of the second paper discharge roller 24, and an entrance transport path 31 is disposed from this branch point to the above-described left entrance part of the lower transport unit 176. I have. Further, a lower transport entrance sensor 190 for monitoring the paper transport state is disposed downstream of the lower transport entrance roller 186 in the transport direction as shown in FIG.

The lower transport section 176 is connected to the entrance transport path 31.
Is provided with a lower transport path connected so as to connect to the lower transport path. The lower transport path is configured to be sandwiched between the upper transport guide 34 and the lower transport guide 35 as shown in FIGS. In the lower transport path, from the upstream side to the downstream side in the transport direction (from left to right in the drawing), first and second for performing a setback operation described later.
Setback rollers 178 and 180 are disposed.

The first setback roller 178 is composed of a transport roller driven by a drive source (not shown), a pressure roller that sandwiches the recording paper between the transport roller and transports the recording paper together with the transport roller. And a plurality of pairs of these transport rollers and pressure rollers are arranged in the axial direction. Also, the second setback roller 180
Like the first setback roller 178, the pair is constituted by a plurality of pairs of conveying rollers and pressure rollers arranged in the axial direction. At this time, both pressure rollers are supported by a leaf spring, and are configured to apply a predetermined pressure to a plurality of recording sheets.

Further, a flat lower transport flapper 194 is provided on the lower transport path 176 further downstream of the second setback roller 178 in the transport direction so as to be rotatable about a shaft 194a. . The lower transport flapper 194 extends obliquely downward from the downstream side in the paper feeding direction (right direction in the drawing) toward the upstream side.
As a result, the lower end portion is lowered by swinging counterclockwise in the drawing, and appears in the lower transport path 176. This lower transport flapper 194
Is in contact with the lowermost recording paper 330 of the tiled recording paper, and the lowermost recording paper 3
30 along the lower conveying guide 35,
Another recording paper 332 stacked on the upper side is guided to the upper surface side of the lower transport flapper 194 to be separated. The swing mechanism and separation operation of the lower transport flapper 194 will be described later.

Further, a lower transport outlet sensor 196 for monitoring the paper transport state is disposed on the upstream side of the lower transport flapper 194 in the transport direction as shown in FIG. Further, near the outlet of the lower transport path 176, a re-feed roller 2 for re-feeding the recording paper to the above-described transfer area is provided.
00 is arranged. The re-feeding roller 200 includes a lower re-feeding driving roller 200a driven by the driving source 110 as shown in FIG.
00a and the recording paper (the lower transport flapper 194 described above).
To separate the stacked recording papers one by one.
Sheet of recording paper) and the re-feed driving roller 20
0a and an upper re-feeding driven roller 200b for conveying the recording paper. These re-feed driving rollers 200a
Further, two pairs of the paper re-feeding driven rollers 200b are arranged in the axial direction.

The refeeding driven roller 20 disposed on the upper side
0b, the rotating shaft protruding from both ends of the re-feeding driven roller 200b is pressed downward by a pressing biasing force of a spring member (not shown), and the re-feeding driven roller 200b is pressed by the pressing force. , So as to be pressed against the re-feed driving roller 200a.

On the other hand, at the connection between the above-mentioned entrance conveyance path 31 and the lower conveyance path 176, the trailing end of the recording paper that branches off at this position and deviates from the entrance conveyance path 31 during the setback operation is located at the lower left side in the figure. A recording paper rear end guide that guides toward the recording paper is provided. The trailing edge guide of the recording paper is provided similarly in the prior art.

Next, the swing mechanism of the lower transport flapper 194 will be described in detail. Flat lower flapper 19
Numeral 4 is disposed over substantially the entire width of the lower transport path 176, and swings around a shaft 194a projecting in the paper width direction from both ends in the width direction of the flapper 194. Then, the flat lower flapper 19 is formed.
4 is provided with a plurality of notches having a substantially U-shape in a plane at a portion that interferes with the above-described re-feed roller 200, and a re-feed roller 200 is disposed in each of the notches.

The lower transport flapper 194 is provided with a motion conversion transmitting means (not shown) for causing the lower transport flapper 194 to perform a recording paper separating operation by using one re-feed roller 200 as a driving source. This motion conversion transmitting means is provided by the re-feed roller 2.
A rotation transmitting means is provided which includes a small-diameter drive pulley fixed to the rotary shaft of No. 00 and a large-diameter driven pulley arranged so as to press against the drive pulley. In the present embodiment, the rotation ratio between the small-diameter drive pulley and the large-diameter driven pulley is set to have a 4: 1 deceleration relationship. This is to swing the flapper 194 at an appropriate timing with respect to the length of the recording paper.

In the thus constructed roofing apparatus, a roofing control device is attached to the DC controller 300 as shown in FIG. This DC controller 30
The stacking control device 0 controls the operation of the stacking device, and has a central processing unit (microcomputer; hereinafter, referred to as “CPU”) as a main part. Note that the DC controller 300 is also provided with a unit for controlling correction of a deviation of a recording sheet described later.

The output ports of the above-described paper discharge sensor 174, registration sensor 124, lower transport inlet sensor 190, lower transport outlet sensor 196, and flapper sensor (not shown) are connected to the input ports of the CPU.

A power switch is also connected to the input port of the CPU to detect whether power is turned on.

The input port of the CPU is connected to a ROM storing a control program such as a stacking control procedure and the like. The input / output port of the CPU is connected to an input / output port of the CPU.
A RAM for temporarily storing various data is connected. Further, a ROM constituting a recording paper deviation correction control means described later is also connected.

On the other hand, the output port of the CPU has a driver for the drive motor of the second paper discharge roller 24 and the lower conveyance inlet roller 186 having a common drive source, and the first drive motor having a common drive source. The transport roller 178a of the setback roller 178 and the second setback roller 18
The driving motor driver for the transport roller 180a, the re-feeding driving roller 200a of the re-feeding roller 200 having a common driving source, and the driving motor driver for the registration roller 122 are connected to each other. As described above, the re-feed driving roller 200a and the registration roller 122 have a common drive source. However, the registration roller 122 is driven by the main motor 110 of the copying machine, and the re-feed driving roller 200a Is configured to operate with the clutch 198 connected to the main motor 110 as appropriate.

The above-mentioned CPU includes the above-mentioned sensors 124,
174, 190, 196,..., And the elapse of a built-in timer and the presence or absence of power-on by the above-described power switch, and is configured to send a drive command to each driver (not shown).

In the paper feeder according to the embodiment of the present invention having the above-described configuration, when the recording paper is stacked in the duplex conveying unit 176, the recording paper is moved in the width direction, that is, in the direction perpendicular to the paper feed direction. Therefore, the lateral registration roller 202 is controlled so as to move in the axial direction thereof, and has a configuration capable of correcting the deviation. This configuration will be described with reference to FIGS.

First, the horizontal registration roller 202 and its operating device will be described with reference to the perspective view of FIG. 11. The horizontal registration roller 202 is driven to rotate by a drive motor 400, and is interposed between a driven roller 503 and a directly linked driven roller 503. It is configured to feed the recording paper 204 in a sandwiched manner. More specifically, the lateral registration rollers 202
The horizontal registration roller drive motor 4 supported by the shaft portion 506
00, and is provided so as to be able to move laterally on the shaft 506 in the direction of arrow C in the figure, and further, a horizontal registration gear 501 to which rotation of the horizontal registration motor 210 is transmitted via an idle gear 500. Have.

The lateral registration gear 501 is sandwiched between a mounting plate (not shown) of the lateral registration motor 210 and a body frame (not shown), and is supported so as to be rotatable without moving in the axial direction. At the center of the lateral registration gear 501, a right-threaded internal gear having a pitch of 3 mm is provided. On the other hand, the shaft 506 has
Push screw 502 integrally with roller itself in axial direction
The lateral registration gear 501 is configured to mesh with and engage with the push screw 502.

The idle gear 500 is freely rotatably supported by the switching arm 505 and has a solenoid 208.
Is engaged with or separated from the lateral registration gear 501. The switching arm 505 has a middle portion pivotally supported by the apparatus main body 10 and operates a link mechanism connected to the vicinity of the idle gear 500 or to a support shaft thereof by the movement of the solenoid 208 in the direction of the arrow. A spring is attached between the end of the switching arm 505 and the tightening portion 507 attached to the end of the shaft 506 so that the idle gear 500 meshes with the gear of the lateral registration motor 210 and the lateral registration gear 501 by this spring. Being energized.

Further, as shown in FIG. 11, a horizontal registration sensor 206 provided in the vicinity of the horizontal registration roller 202 detects a horizontal registration roller 202 based on a detection result.
In order to control the recording paper 204 to move in the axial direction, a deviation of the recording paper 204 in the width direction is detected. The horizontal registration sensor 206 is moved in the width direction by the horizontal registration motor 202 according to the size of the recording paper to be copied, as described later in detail, and stands by at the position of the size selected by the operator.
As described above, the means for detecting the position in the width direction of the recording paper includes:
As shown in FIG. 12, an optical or mechanical position detecting device that outputs a signal when the ON position is attained, and is arranged in a positional relationship between the re-feed roller 200 and the recording paper.

Next, among the operations of the copying machine having the above-described structure, the operation of the above-described laying apparatus when duplex printing is performed will be described below. Paper cassette 1
8, the recording paper 182 is fed from the paper feed roller 11
2. When the sheet is conveyed to the registration rollers 122 via the conveyance path 21 and the merged conveyance path 17 and the like, and the manual tray 22 is used, the recording paper is conveyed to the manual paper feed roller 20, the manual conveyance path 21 and the merged conveyance path 17. The sheet is conveyed to the registration roller 122 via the like. The recording paper conveyed in this manner is controlled by the registration roller 122 so as to coincide with the leading end of the image on the photosensitive drum 126, and is transferred by the transfer charger 160, separated by the separation charger 160,
An image is formed on one side through conveyance by a belt-shaped paper conveyance path and fixing by the fixing device 164.

Recording paper 330 that has passed through fixing device 164
As shown in FIG. 4, the first and second discharge rollers 1
The paper is conveyed by 70 and 172 so that a part of the paper (conveying front end portion) is discharged to the paper discharge tray 26. At this time, the lower transport entrance roller 186 is rotating in the same direction because the second discharge roller 172 and the drive source 184 are common. When a predetermined time has passed since the passage of the trailing edge of the recording paper 330 by the paper ejection sensor 170 is detected, the second paper ejection roller 17
2 stops the rotation while holding the rear end of the recording paper 320. Thereafter, the second paper discharge roller 172 rotates in the reverse direction, and the rear end (the right end in the figure) of the recording paper 330 enters the entrance conveyance path as shown in FIG. At this time, the lower conveyance inlet roller 186 is also connected to the second paper discharge roller 17.
2, the recording paper 330 is conveyed toward the lower conveyance path as shown in FIG. Here, since the transport direction is reversed, the right end in the figure is the leading end of the recording paper 330, and the left end in the figure is the rear end of the recording paper 330.

When a predetermined period of time has elapsed since the rotation of the second discharge roller 172 and the lower conveyance inlet roller 186 has been reversed, the first recording paper 330 on which an image has been formed on one side is formed.
As shown in FIG. 6, the first setback roller 176, whose leading end enters the lower transport path and is stopped,
And a loop is formed at the tip. At this time, as shown in FIG.
The cam convex surface of the flapper cam comes into contact with the lower transport flapper 194 by the driving force a, and the lower end portion of the lower transport flapper 194 is lowered so as to appear on the lower transport path.
At the same time, the first and second setback rollers 178 and 180 start rotating in the forward direction (the direction in which the recording paper is turned to the right in the drawing), and the recording paper 330 advances in the lower transport path (shown in the figure). (Going to the right) and the trailing edge exits the entrance transport path.

When a relatively short recording sheet such as A4 in the transport direction is used as in this embodiment, the first
When the rear end of the recording paper 330 is removed from the entrance conveyance path by the rotation of the second setback rollers 178 and 180,
The leading end of the recording paper does not reach the re-feed roller 200.
When a relatively long recording sheet such as A3 is used in the transport direction, the first and second setback rollers 178,
When the trailing edge of the recording paper exits the entrance transport path due to the rotation of r180, the course of the leading edge of the recording paper is changed upward by the lower transport flapper 194 that is lowered.

When the lower transport entrance sensor 190 detects that the trailing end of the recording paper 330 has been removed from the entrance transport path, as shown in FIG.
0a, the concave surface of the flapper cam comes into contact with the lower transport flapper 194, the lower end portion of the lower transport flapper 194 rises to the non-operating position, and the lower transport path is opened. The rotation of the second setback rollers 178 and 180 is reversed. Then, the recording paper 3
Reference numeral 30 retreats while the rear end enters the discharge conveyance path 42 according to the conveyance. When a predetermined time elapses after the rotation of the first and second setback rollers 178 and 180 is reversed, the rotation of the setback rollers 178 and 180 stops. At this time, the leading end of the recording paper 330 is located at a position protruding rightward in the figure by a predetermined distance 1 from the first setback roller 178.

Subsequently, in the same manner as described above, the second recording sheet 332 having an image formed on one side is conveyed to the lower conveying path 176 as shown in FIG. As shown in FIG. 6, the second recording paper 332 also has its leading end abutting on the stopped first setback roller 178, and a loop is formed at its leading end. At this time, as shown in FIG. 7, the cam convex surface of the flapper cam (not shown) abuts on the lower transport flapper 194 by the driving force of the re-feed driving roller 200a, and the lower end of the lower transport flapper 194 is moved downward. Go down to appear on path 176. At the same time, the first and second setback rollers 178 and 180 start rotating in the forward direction, and the first recording paper 330 and the second recording paper 332 move forward along the lower transport path together. The rear end of the second recording paper 332 exits the entrance conveyance path.

When the lower transport entrance sensor 190 detects that the trailing end of the second recording paper 332 is removed from the entrance transport path, the driving force of the re-feed driving roller 200a causes the cam concave surface of the flapper cam to move downward. 194, the lower end portion of the lower transport flapper 194 rises to the inoperative position to open the lower transport path, and at the same time, the rotations of the first and second setback rollers 178, 180 are reversed. The recording papers 330 and 332 move backward while their respective rear ends enter the discharge conveyance path 42 according to the conveyance.
When a predetermined time elapses after the rotation of the first and second setback rollers 178 and 180 is reversed, the rotation of the setback rollers 178 and 180 stops. At this time, the leading end of the second recording paper 332 is located at a position protruding rightward in the drawing from the first setback roller 178 by a predetermined distance 1 similar to the case of the first recording paper 330.

The same operation as described above is repeated for the third and subsequent recording papers, and a large number of recording papers are stacked in a tile shape on the lower transport path. Here, in this embodiment, up to 20 recording sheets can be stacked in a tile shape.

When the final copy on one side is stacked in a tile pattern, the first and second setback rollers 178, 1
80 starts to rotate in the forward direction, and the lower conveyance exit sensor 196
As a result, the entire stack of recording paper is advanced until the passage (projection to the right in the drawing) of the leading end of the first recording paper (the lowermost recording paper) 330 is detected.

When the leading end of the first recording paper 330 is detected by the lower conveyance exit sensor 196, as shown in FIG. 7, the first and second setback rollers 178, 18 are provided.
The rotation of 0 is reversed and the leading edge of the first recording paper 330 passes by the lower conveyance exit sensor 196 (pulls to the left side in the figure).
, The entire stack of recording papers is retracted until rotation of the setback rollers 178 and 180 is stopped. Thus, a double-sided copy standby state is set.

Here, a copy start key (not shown)
Is pressed, as shown in FIG.
Setback rollers 178 and 180 start to rotate in the forward direction, and the entire stack of recording paper advances. Assuming that a predetermined time has elapsed since the lower conveyance exit sensor 196 detects the passage of the leading end of the first recording paper 330, the set back rollers 178 and 180 stop rotating, and the recording paper is stopped. Reference numeral 330 indicates a standby state at the separation position.

At this time, as shown in FIG. 8, the re-feed driving roller 200a starts rotating, and the driving force of the re-feed driving roller 200a causes the cam convex surface of the flapper cam to move to the lower transport flapper 194.
And lowers so that the lower end portion of the lower transport flapper 194 appears on the lower transport path. By the lowering operation of the lower end portion of the lower transport flapper 194, the base portion on the opposite side is raised. Then, when the base end portion comes into contact with the flapper sensor and is turned on, the first and second setback rollers 178 and 180 resume rotation in the forward direction.

Then, as shown in FIG. 9, the lower recording flapper 194 causes the lowermost first recording papers 330 and 2 to move.
The first and subsequent sheets of recording paper 332 are separated from each other, and the first sheet of recording paper 330 is conveyed along the exit conveyance path by the setback rollers 178 and 180 and the re-feed roller 200.
The second and subsequent recording papers 332 are transferred to the lower transport flapper 194.
Changes the course upward.

The first and second setback rollers 178,
When a predetermined time has elapsed since the rotation of the first and second setback rollers 178, 1
80 is reversed, and the lower conveyance outlet sensor 196 detects
Until the passage of the leading end of the recording paper 332 (pulling to the left side in the figure) is detected, all the second and subsequent stacked recording papers are retracted. At this time, the first recording paper 330 is
Setback roller 180 has already been removed. When the leading end of the second recording paper 332 is detected by the lower conveyance exit sensor 196, the setback roller 178,
When the rotation of 180 is stopped, the lower transport flapper 19
4 goes up.

The first recording paper 330 is conveyed to the merging conveyance path, and when the leading end is detected by the registration sensor 124, the re-feeding operation of the second recording paper 332 is performed by the above-described first paper. Start in the same way as the recording paper
Be executed. The refeeding operation for the third and subsequent recording sheets is performed in the same manner.

The transfer, separation, conveyance, and fixing of the recording paper which is prevented from being double-fed by the above-described stacking device and which is surely separated one by one and sequentially re-fed are the same as in the case of one side. The image is formed on the back side, and the double-sided copy is completed.

As described above, in this embodiment, the rotational driving force of the paper re-feed roller 200 is transmitted via the pulley and the flapper cam as the motion conversion transmitting means without adding a separate driving source such as a conventional solenoid. Lower transport flapper 19
4 oscillates at a predetermined timing, whereby the lower transport flapper 194 performs an operation of separating recording paper.

At this time, in the present embodiment, since the cam mechanism is employed as the motion conversion transmitting means, a predetermined operation can be satisfactorily and reliably obtained with a simple configuration.

Next, in the paper feeder of the image forming apparatus having the above-described configuration, when the recording paper is stacked in the double-sided conveyance unit 176, a deviation in a direction orthogonal to the paper feed direction, which is the width direction, is taken. Is dealt with in the correction mechanism having the configuration described with reference to FIG. 11 described above.
3 will be described.

First, the correction control in the width direction of the horizontal registration roller 202 will be described with reference to FIG. 13. The horizontal registration roller 202 can move in the width direction of the arrow C1 or C2. In the case of the correction by the movement in the C1 direction shown, the gear of the lateral registration motor 210 meshes with the idle gear 500 of the switching arm 505 and the lateral registration gear 501, and
When the gear 10 rotates in the F1 direction, the idle gear 50
0 transmits the rotation so that the lateral registration gear 501 rotates in the E1 direction, and the lateral registration gear 501 rotates in the D1 direction.

The right-hand thread of the internal teeth at the center of the lateral registration gear 501 meshes with a thread portion of a bush screw 502 provided at an end of the lateral registration roller 201, and the movement of the lateral registration gear 501 in the axial direction is restrained. For this reason, the bush screw 502 that is axially integrated with the horizontal registration roller 202 can move the horizontal registration roller 202 in the axial C1 direction as the horizontal registration gear 501 rotates. In the C2 direction, which is the opposite direction of the lateral registration roller 202, the gear of the lateral registration motor 201 rotates in the F2 direction, the lateral registration gear 501 rotates in the D2 direction, and the screw of the bush screw 502 causes the lateral registration roller 202 to rotate. It can be moved in the C2 direction.

Next, in the width direction of the horizontal registration roller 202,
That is, the control described below with reference to FIG. 13 is performed so that the lateral registration sensor 202 detects the axial deviation and the lateral registration roller 202 corrects the axial deviation based on the detection result. You. Horizontal registration sensor 206
Moves in the width direction according to the paper size to be copied, and stands by at the position of the paper size selected by the operator as shown in FIG. The lateral registration sensor 206 is moved in the axial direction by a lateral registration motor 210, and the linear motion of the solenoid 208 is transmitted to a switching arm 505 via a link mechanism to swing, and the gear of the lateral registration motor 210 and the lateral movement are moved. Although not shown in the figure, the rotational movement is changed to the axial movement by the action of the lateral registration gear and the bush screw, which are omitted in the figure, by meshing with the gear of the registration sensor 206. Thus, the standby position of the horizontal registration sensor 206 is set according to the paper size.

To explain the actual correction function, the recording paper 204 that has passed the re-feed roller 200 reaches the horizontal registration roller 202, and the horizontal registration roller 202 is still stopped. And between the horizontal registration roller 202 and the recording paper 20.
4, a loop is formed, and the skew is corrected. At this time, the rotation of the horizontal registration roller 202 is performed by a horizontal registration roller drive motor 400.

First, when the lateral registration roller motor 400 is turned on by an instruction from the DC controller 300 provided with a shift correction control means, the horizontal registration roller 2
02 rotates and conveys the recording paper 204, and at the same time, the lateral registration sensor 206 starts detecting the position of the recording paper 204 in the width direction as described later.

There are two positional relationships between the horizontal registration sensor 206 and the recording paper 204 at the time of starting the position detection. In each case, the movement of the horizontal registration roller 202 when correcting a shift in the width direction. This will be further described with reference to FIGS. 12 and 13.

First, when the recording paper 204 is at the OFF detection point of the horizontal registration sensor 206 as shown in FIG. 12, that is, when the recording paper is displaced and the horizontal registration sensor 206 is not at the ON position, the recording paper 204 Is moved in the direction in which the horizontal registration sensor 206 is turned on by the above-described operation, and when the horizontal registration sensor 206 is turned on, the movement is stopped and the correction is completed. Conversely, if the horizontal registration sensor 206 is already ON, that is, if the recording paper 204 has entered the ON position of the horizontal registration sensor 206, the above-described correction mechanism will be used until the horizontal registration sensor 206 turns OFF. The horizontal registration roller 20
After moving 2, move it again in the opposite direction until it turns ON.
When the horizontal registration sensor 206 is turned ON, the movement of the horizontal registration roller 202 is stopped, and the correction operation ends. Such a correction operation of the recording paper must be completed before the recording paper 204 hits the registration roller 122 to form a loop and the registration roller 122 starts rotating.

Here, in the image forming apparatus to which such a paper feeder is applied, the moving speed of the lateral registration roller 202 at the time of correction in the axial direction is 5 mm / sec. In order to finish the correction earlier, it is desirable that this speed is faster. However, when the speed is increased, the motor becomes larger, the components of the mechanism become thicker, and the vibration and noise increase. Problem, usually 5 mm / sec. Have been on the speed of travel. On the other hand, the transport path length between the horizontal registration roller 202 and the registration roller 122 is 120 mm, and in this apparatus, the paper feeding speed is 180 mm / sec.
c. Therefore, the time required to reach the registration roller 122 from the horizontal registration roller 202 is 0.67 seconds. Further, the time from when the leading edge of the recording paper reaches the registration roller 122 to when the registration roller 122 starts is 0.1 second, and therefore, the correction operation is 0.67+
It must be done within 0.1 = 0.77 seconds. As described above, the moving speed of the lateral registration roller 202 in the axial direction is 5 mm / sec. , The correction amount within 0.77 seconds is a maximum of 3.85 mm. Normally,
A correction of 3.85 mm is sufficient, but the deviation in the width direction of the recording sheet may exceed 3.85 mm due to environmental conditions and differences in paper type. Therefore, in the above embodiment, when the recording paper is conveyed from the horizontal registration roller 202 for 0.4 seconds, the positional relationship between the horizontal registration sensor 206 and the recording paper is detected to determine whether or not the correction operation has been completed. . The grounds for transporting the recording paper for 0.4 seconds will be described later.

Therefore, as a function of the deviation correction control means for the recording paper, if the correction operation is not completed, as one embodiment, the rotation speed of the horizontal registration roller drive motor 400 is reduced to reduce the rotation of the horizontal registration roller. Roller 202
Is 180 mm / sec. To 100mm / s
ec. And the remaining time of the correction operation is 0.3
It is extended from 7 seconds to 0.58 seconds. By this extension, the correction time is extended by 0.21 seconds from 0.77 seconds to 0.98 seconds, and the maximum correction amount is increased from 3.85 mm in the previous state to 4.9 mm to 1.05 mm. Will be increased. In this case, the image forming time for one double-sided copy takes 0.21 seconds longer, but the operation of this embodiment is rarely performed, and there is no practical problem.
Note that the transport speed of the lateral registration roller 202 is 100 mm /
sec. The conveyance speed of the re-feed roller 200 is 180 mm / sec. (180-
100) A loop of X0.21 = 16.8 mm is formed between the two rollers.
It is absorbed by the loop forming space 214 for skewing on the upstream side of 2 (see FIG. 3).

Next, another embodiment will be described.
As in the above-described embodiment, at the time when 0.4 seconds have elapsed, it is detected whether or not the correction operation has been completed. If the correction operation has not been completed, the rotation speed of the lateral registration motor 210 is increased.
The horizontal registration roller 202 is operated to increase the moving speed in the width direction. In this embodiment, the moving speed in the width direction is 5 mm / sec. , And a maximum correction of 3.85 mm is performed during the correction time of 0.77 seconds. If the correction is not completed 0.4 seconds after the start of the correction, the moving speed of the lateral registration roller 202 in the width direction, that is, the axial direction, is set to 5 mm / sec. From 10 mm / sec. , The correction amount in the remaining 0.37 seconds increases from 1.85 mm to 3.7 mm, and totals from 3.85 mm to 5.7 mm. In this case, in order to increase the speed of the drive motor of the lateral registration roller 202, it is necessary to increase the size of the motor. It is conceivable to operate at the speed of, but as described in the above embodiment, considering the problems such as the increase in vibration and noise caused by the increase in speed,
Usually, 5 mm / sec. At a speed of 10 mm / sec. It is better to increase the speed. Needless to say, the above embodiment and the operation of this embodiment may be combined.

As described above, the normal correction amount is 3.85 mm, but may exceed 3.85 mm depending on the environmental conditions, the type of recording paper, the lot, and the like.
According to the experimental data so far, the maximum correction is about 1 mm and the correction amount is about 4.95 mm. In both embodiments, in consideration of the actual value of the correcting operation of the horizontal registration roller 202 and the experimental data when the correction amount exceeds the correction amount, the correction time of the horizontal registration roller 202 is about 1/2 of 0.77 seconds. That is, when the horizontal registration roller 202 sends out the recording paper in 0.4 seconds, the correction amount of the recording paper is 3.85 mm.
The above-described operations of both embodiments are applied until the remaining time reaches the registration roller 122. Therefore, as described above, when the execution force and the correction amount of the correction operation of the lateral registration rollers are different, it goes without saying that the state is different from that of the above-described embodiment.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the invention. For example, the present invention is not limited to a paper feeder provided with a misalignment correction control unit for a recording sheet together with the tiled device of the two-sided image forming apparatus as in the above-described embodiment. The same can be applied to the device.

It is needless to say that the present invention can be similarly applied to an image forming apparatus other than a copying machine.

[0077]

As described above, in the image forming apparatus provided with the paper feeder according to the present invention, when the amount of movement of the horizontal registration roller in the axial direction exceeds a predetermined value, the transport speed of the horizontal registration roller is reduced. By lowering, the time required to reach the next roller can be extended, the amount of correcting the deviation in the width direction of the recording paper can be increased, and a paper feeding device having good paper feeding performance can be obtained. . Then, an image with good image quality can be obtained on the recording paper with little deviation in the recording paper width direction.

Further, in the image forming apparatus provided with the paper feeder according to the present invention, by increasing the moving speed of the lateral registration roller in the axial direction, the width of the lateral registration roller itself can be maintained in the width direction while maintaining the feed speed. Since the misaligned recording paper can be smoothly corrected, a paper feeder having a good paper feed performance can be similarly provided, and good image quality can be obtained.

Further, in the image forming apparatus provided with the paper feeding device according to the present invention, the transport speed of the lateral registration roller as described above is reduced and the moving speed in the axial direction is increased, so that the deviation of the recording paper can be further reduced. There is an excellent effect that a sufficient time can be taken for the correction and that a good paper feeding performance can be obtained. Therefore, excellent image quality can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external appearance of an image forming apparatus incorporating a paper feeder according to the present invention.

FIG. 2 is a cross-sectional view of an image forming apparatus incorporating a tiled device to which a paper feeding device according to the present invention is applied.

FIG. 3 is an explanatory side view showing a transport path of a tiled device in the image forming apparatus shown in FIGS. 1 and 2;

FIG. 4 is a partially enlarged side view illustrating a main part of the transport path shown in FIG. 3 and illustrates an operation state of loading paper on a duplex unit.

5 is a partially enlarged side view illustrating a state in which a recording sheet enters an entrance conveyance path in the conveyance path illustrated in FIG. 4;

FIG. 6 is a partially enlarged side view illustrating a state in which the recording paper is transported downward from the entrance transport path in the transport path shown in FIG. 5;

FIG. 7 is a partially enlarged side view illustrating a next state of the recording paper in the conveyance path illustrated in FIG. 6;

8 is a partially enlarged side view illustrating the state of the next recording sheet on the conveyance path shown in FIG. 7;

9 is a partially enlarged side view illustrating a separated state of the second and subsequent recording sheets on the transport path shown in FIG. 8;

10 is a drive system diagram of a drive motor of each roller in a recording paper conveyance path in FIG. 2;

FIG. 11 is a perspective view of a main part of a recording paper misalignment correction mechanism in a horizontal registration roller in the paper feeding device according to the present invention.

12 is an explanatory diagram illustrating a relationship between a lateral registration sensor and a paper edge in the correction mechanism illustrated in FIG. 11;

FIG. 13 is a flowchart illustrating an operation of a horizontal registration mechanism in a transport path to which the paper feeding device according to the present invention is applied.

[Explanation of symbols]

 122 Registration roller 202 Horizontal registration roller 204 Recording paper 206 Horizontal registration sensor 208 Solenoid 210 Horizontal registration motor 300 DC controller with misalignment correction control means 500 Idle gear 501 Horizontal registration gear 502 Bush screw 505 Switching arm

Continued on the front page F-term (reference) 2C059 AA12 AA19 AA26 AA32 AA43 AA55 AA64 BB11 2H072 AA03 AA13 AA22 AB00 CA01 CB09 HB09 3F048 AA02 AA04 AA05 AB01 BA20 BA22 BA27 BB05 CC05 DA07 DC12 EA15 A02 EB24 A02 EB24 CB02 DA05 EA03 FA03 FA05

Claims (6)

[Claims] 1. A means for detecting a deviation in a width direction of the recording sheet which is a direction orthogonal to a conveying direction of the recording sheet being conveyed, and the recording sheet is nipped and conveyed, and the recording sheet is conveyed in the width direction during conveyance. A lateral registration roller for laterally moving the recording paper to correct the width direction position of the recording paper; and a means for driving the lateral registration roller to laterally move in the width direction based on a signal corresponding to a deviation from the detection means. And another conveying roller provided to convey the recording paper sent from the lateral registration roller further downstream, and a means for detecting a deviation of the recording paper detects a deviation amount exceeding a predetermined amount. In this case, before the leading end of the recording paper reaches the other transport roller, the paper feed speed or the lateral movement speed of the lateral registration roller is adjusted to complete the correction by the lateral movement. Paper conveying apparatus of an image forming apparatus, comprising: the means. 2. A means for detecting a deviation in a width direction of the recording sheet, which is a direction orthogonal to a conveying direction of the recording sheet being conveyed; A lateral registration roller for laterally moving the recording paper to correct the width direction position of the recording paper; and a means for driving the lateral registration roller to laterally move in the width direction based on a signal corresponding to a deviation from the detection means. And another conveying roller provided to convey the recording paper sent from the lateral registration roller further downstream, and a means for detecting a deviation of the recording paper detects a deviation amount exceeding a predetermined amount. In this case, the lateral movement speed of the lateral registration roller in the width direction is increased, and before the leading end of the recording paper reaches the other transport roller, the lateral movement of the recording paper in the width direction by the driving unit is performed. End Paper conveying apparatus of an image forming apparatus characterized by having a deviation correction control means of the recording paper to. 3. A means for detecting a deviation in a width direction of the recording sheet, which is a direction orthogonal to a conveying direction of the recording sheet to be conveyed; A lateral registration roller for laterally moving the recording paper to correct the width direction position of the recording paper; and a means for driving the lateral registration roller to laterally move in the width direction based on a signal corresponding to a deviation from the detection means. And another transport roller provided to transport the recording paper sent from the lateral registration roller further downstream, wherein the means for detecting the deviation of the recording paper has a deviation amount exceeding a predetermined amount. If detected, the paper feed speed of the lateral registration roller is reduced, and before the leading end of the recording paper reaches the other transport roller, the lateral movement of the recording paper in the width direction by the driving unit is completed. Paper conveying apparatus of an image forming apparatus comprising: the Rokushi speed adjusting means. 4. A means for detecting a deviation in a width direction of the recording sheet, which is a direction orthogonal to a conveying direction of the recording sheet to be conveyed; A lateral registration roller for laterally moving the recording paper to correct the width direction position of the recording paper; and a means for driving the lateral registration roller to laterally move in the width direction based on a signal corresponding to a deviation from the detection means. And another transport roller provided to transport the recording paper sent from the lateral registration roller further downstream, wherein the means for detecting the deviation of the recording paper has a deviation amount exceeding a predetermined amount. If it is detected, the paper feed speed of the lateral registration roller is reduced, and the lateral movement speed of the lateral registration roller in the width direction is increased, so that the leading end of the recording paper reaches the other conveyance roller before reaching the other conveyance roller. Paper conveying apparatus of an image forming apparatus characterized by and a control means for terminating the lateral movement in the width direction of the recording paper by means of driving. 5. The image forming apparatus according to claim 1, wherein the lateral registration roller according to claim 1, 2, 3, or 4 is disposed at an exit of a double-side refeed unit. 6. The image forming apparatus according to claim 1, wherein the other conveying roller is a main registration roller that conveys a recording sheet toward a transfer unit. Equipment paper transport device.