JP3268274B2 - Paper transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper conveying apparatus for forming a nip portion by pressing a first rotary member and a second rotary member against each other, and gripping and transporting a sheet in the nip portion. is there.

[0002]

2. Description of the Related Art Conventionally, for example, a conveying path for conveying a sheet (sheet) fed from a sheet feeding device in an image forming apparatus to an image forming section, or a sheet on which an image is formed in the image forming section is discharged. 2. Description of the Related Art In a sheet (sheet) conveying device in a conveying path for conveying a sheet, a sheet conveying device that sequentially conveys a sheet while gripping (nipping) a nip between a pair of rotating bodies (rollers) is used.

In this sheet conveying apparatus, stable sheet conveying properties are required irrespective of the type of the sheet to be conveyed. On the other hand, the sheet conveying apparatus has no mechanical variation due to the pressing force of the rollers of each apparatus. Must be.

If the sheet transportability is not stable,
There is a possibility that the timing at which the sheet is fed to the image forming unit differs for each sheet, and the position where the image is formed on the sheet slightly changes every time. In addition, from the viewpoint of service work, it is required that the roller can be removed from the apparatus frame as easily as possible in order to replace parts of the roller or to clean the roller.

[0005] As a conventional roller pressing mechanism,
There was one described in JP-A-6-27754. The press-contact mechanism for pressing the first roller against the second roller disclosed in this publication bridges a spring in an arch shape at both ends of a rotation shaft of the first roller, and applies an urging force of the spring. Thus, the first roller is brought into pressure contact with the second roller.

[0006] A pressing mechanism for pressing the second roller against the first roller is provided at both ends of the rotating shaft of the second roller with a side surface of a bearing supporting portion for rotatably supporting the rotating shaft. In some cases, the bearing support is pressed toward the first roller by a spring.

[0007]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Laid-Open No. 6-277 is disclosed.
In the first roller pressing mechanism disclosed in Japanese Patent Application Publication No. 54-54, a structure in which a spring is merely wound around the peripheral surface of the rotating shaft of the first roller, the first roller is pressed against the second roller. There is a possibility that a predetermined pressure contact force may not be obtained due to a variation in the force, and the spring must be removed when the first roller is replaced or attached / detached by the service work. There was a problem such as falling.

In the case of the second roller pressing mechanism,
When removing the second roller, the pressing force of the spring must be released, and the bearing support and the spring must also be removed from the device. Therefore, the second roller cannot be removed. In addition, there has been a problem that components such as a spring and a bearing support are lost.

The present invention has been made in view of the above problems, and a stable pressing force is obtained by pulling a first rotating body from a position sandwiching a second rotating body and pressing the first rotating body against the second rotating body. The purpose is to obtain.

[0010] In order to solve the above-mentioned problems, a paper conveying apparatus according to the present invention forms a nip portion by pressing a first rotary member and a second rotary member against each other, and grips a sheet in the nip portion. In the paper transport device for transporting, the rotary shaft of the first rotating body is inserted and has an insertion hole for rotatably supporting the rotating shaft, and the first rotary body is pressed against the second rotary body. A rotating body support that is slidably engaged with the apparatus frame, one end of which is attached to the rotating body support, and the other end of which is attached to the apparatus frame, respectively.
Of the rotary member, and a spring for urging so as to each other press is moved to the second rotating body direction, the rotary member <br/> support against the biasing force of the spring, the first
In a direction in which the first rotating body is separated from the second rotating body,
One release of engagement of the apparatus frame without removing the spring capable provided and is configured to be engaged with the apparatus frame in a state of detaching the first rotating body.

[0011]

According to another aspect of the present invention, there is provided a sheet transporting apparatus for transporting a sheet by pressing a first rotary body and a second rotary body against each other to transport a sheet. A rotatable support member rotatably and detachably provided, the rotatable support member being movable relative to an apparatus frame rotatably supporting the second rotator. A spring is provided between the rotating body support and the device frame for engaging and moving the first rotating body in the direction of the second rotating body and pressing the spring, without removing the spring. the first rotating body above the rotating body support against the biasing force of the spring
The provided so as to disengage with respect to the second rotating said apparatus frame in a direction away from the body, disengagement Jo of
State in is configured to be removable to the first rotating body.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An outline of an image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a front sectional view showing a configuration of a digital color copying machine which is an image forming apparatus of the present invention. A document table 11 is provided on the upper surface of the copying machine body 1.
1 and an operation panel, and an image reading unit 110 and an image forming unit 210 are provided inside the copying machine main body 1.

The upper surface of the document table 111 is supported so as to be openable and closable with respect to the document table 111, and has a predetermined positional relationship with respect to the document table 111 surface.
ADF: Recirculating Automatic Document Fe
eder) 112 is mounted.

Further, the RADF 112 first conveys the original such that one side of the original faces the image reading unit 110 at a predetermined position on the original platen 111, and after the image reading on this one side is completed, the other side. The document is inverted and transported toward the document table 111 such that the surface of the document faces the image reading unit 110 at a predetermined position on the document table 111. Then, the RADF 112 discharges this document after reading the image on both sides of one document, and executes the duplex conveyance operation for the next document. The above-described document conveyance and reverse operation are controlled in relation to the operation of the entire copying machine.

The image reading section 110 is disposed below the document table 111 for reading an image of a document conveyed onto the document table 111 by the RADF 112. The image reading unit 110 has a document scanning body that reciprocates in parallel along the lower surface of the document table 111, an optical lens 115, and a CCD line sensor 116 that is a photoelectric conversion element.

The original scanning body is a first scanning unit 11
3 and a second scanning unit 114. The first scanning unit 113 has an exposure lamp for exposing the surface of the original image, and a first mirror for deflecting a reflected light image from the original in a predetermined direction. , And reciprocates in parallel at a predetermined scanning speed while maintaining the scanning speed. The second scanning unit 114 includes the first
A second mirror for deflecting the reflected light image from the document deflected by the first mirror of the scanning unit toward a predetermined direction;
And reciprocate in parallel while maintaining a constant speed relationship.

The optical lens 115 is connected to the second scanning unit 1
The reflected light image from the document deflected by the third mirror 14 is reduced, and the reduced light image is converted to a CCD line sensor 116.
An image is formed at the upper predetermined position.

The CCD line sensor 116 photoelectrically converts the formed light image sequentially and outputs it as an electric signal. The CCD line sensor 116 is a three-line color CCD capable of reading a black-and-white image or a color image and outputting line data separated into R (red), G (green), and B (blue) color components. . The document image information converted into an electric signal by the CCD line sensor 116 is further transferred to an image processing unit (not shown) and subjected to predetermined image data processing.

Next, the configuration of the image forming unit 210 and the configuration of each unit related to the image forming unit 210 will be described.

Below the image forming section 210, there is provided a sheet feeding mechanism 211 for separating the sheets (recording media) P stored in the sheet tray one by one and supplying the separated sheets P to the image forming section 210. ing. The timing of the sheets P separated and supplied one by one is controlled by a pair of registration rollers 212 disposed in front of the image forming unit 210, and the image forming unit 210 is synchronized with the image forming by the image forming unit 210. Transported again.

Further, a transfer / conveyance belt mechanism 213 is disposed below the image forming section 210. The transfer conveyance belt mechanism 213 includes a driving roller 214 and a driven roller 215.
The paper P is conveyed by electrostatically attracting the paper P to a transfer / transport belt 216 stretched so as to extend substantially in parallel with the sheet P. In addition, a pattern image detection unit is provided near the lower side of the transfer conveyance belt 216.

Further, a fixing device 217 for fixing the toner image transferred and formed on the sheet P on the sheet P is provided downstream of the transfer and conveying belt mechanism 213 in the sheet conveying path.
Is arranged. The paper P that has passed through the nip between the pair of fixing rollers of the fixing device 217 passes through a conveyance direction switching gate 218 and is discharged by discharge rollers 219 onto a paper discharge tray 220 attached to the outer wall of the copying machine main body 1. You.

The switching gate 218 is connected to the sheet P after fixing.
Is selectively switched between a path for discharging the sheet P to the copying machine main body 1 and a path for re-supplying the sheet P toward the image forming unit 210. The sheet P whose transport direction has been switched again toward the image forming unit 210 by the switching gate 218 is turned upside down via the switchback transport path 221, and then the image forming unit 210 is turned over.
Is supplied again.

Also, above the transfer belt 216 in the image forming section 210, the first image forming station Pa, the second image forming station Pb, the third image forming station Pc, and the Four image forming stations Pd are arranged in order from the upstream side of the sheet transport path.

The transfer conveying belt 216 is driven by a driving roller 214.
As a result, the sheet P is frictionally driven in the direction indicated by the arrow Z in FIG. 1 and is gripped by the sheet P fed through the sheet feeding mechanism 211 as described above.
Conveyed sequentially to Pd.

Each of the image forming stations Pa to Pd has substantially the same configuration. Each of the image forming stations Pa, Pb, Pc, and Pd is a photosensitive drum 222a, 222b, or 22 that is driven to rotate in the direction of arrow F shown in FIG.
2c and 222d.

Around the photosensitive drums 222a to 222d, chargers 223a, 223b, 223c, 223d for uniformly charging the photosensitive drums 222a to 222d, respectively.
And developing devices 224a, 224b, and 2 for developing the electrostatic latent images formed on the photosensitive drums 222a to 222d, respectively.
24c, 224d and the developed photosensitive drum 222a
225a, 225b, 225c, 225d for transferring the toner images on the sheet P to the paper P, and cleaning devices 226a, 226b, 226c, 2 for removing the toner remaining on the photosensitive drums 222a to 222d.
26d are sequentially arranged along the rotation direction of the photosensitive drums 222a to 222d.

Each of the photosensitive drums 222a to 222d
Above the laser beam scanner unit (LSU)
227a, 227b, 227c and 227d are provided respectively. LSUs 227a to 227d include a semiconductor laser device (not shown) that emits dot light modulated according to image data, and a polygon mirror (deflecting device) 240 for deflecting a laser beam from the semiconductor laser device in the main scanning direction. Lens 241 and mirror 24 for imaging the laser beam deflected by the polygon mirror 240 on the surfaces of the photosensitive drums 222a to 222d.
2,243 and the like.

A pixel signal corresponding to the black component image of the color original image is stored in LSU 227a, and a pixel signal corresponding to the cyan color image of the color original image is stored in LSU 227b.
A pixel signal corresponding to the magenta color component image of the color original image is input to SU 227c, and a pixel signal corresponding to the yellow color component image of the color original image is input to LSU 227d.

As a result, the electrostatic latent images corresponding to the color-converted original image information are formed on the photosensitive drums 222a to 222d.
Formed on top. The developing device 224a includes the black toner, the developing device 224b includes the cyan toner,
The developing device 224c contains magenta toner, and the developing device 224d contains yellow toner. The electrostatic latent images on the photosensitive drums 222a to 222d are:
The image is developed with the toner of each color. As a result, the document image information color-converted by the image forming unit 210 is reproduced as a toner image of each color.

Further, between the first image forming station Pa and the paper feed mechanism 211, a paper suction (brush) charger 2 is provided.
The paper suction charger 228 charges the surface of the transfer conveyance belt 216,
The sheet P supplied from the first image forming station Pa is securely sucked onto the transfer / conveying belt 216.
To the fourth image forming station Pd without shifting.

On the other hand, a static eliminator (not shown) is provided almost directly above the drive roller 214 between the fourth image forming station Pd and the fixing device 217. An alternating current for separating the paper P electrostatically attracted to the transfer and conveyance belt 216 from the transfer and conveyance belt 216 is applied to the neutralizer.

In the digital color copying machine having the above structure, cut sheet-shaped paper is used as the paper P. The paper P is sent out from a paper feed cassette and fed to the paper feed mechanism 2.
11, the leading end of the sheet P is detected by a sensor (not shown), and a pair of registration rollers 212 is detected based on a detection signal output from the sensor. Is temporarily stopped.

Then, the paper P is fed onto the transfer / conveying belt 216 rotating in the direction of arrow Z in FIG. 1 at the timing of each of the image forming stations Pa to Pd. At this time, since the transfer conveyance belt 216 has been given a predetermined charge by the paper suction charger 228 as described above,
The sheet P is stably conveyed and supplied while passing through the image forming stations Pa to Pd.

In each of the image forming stations Pa to Pd, a toner image of each color is formed, and is superposed on the support surface of the paper P conveyed by being electrostatically attracted and conveyed by the transfer conveyance belt 216. When the transfer of the image by the fourth image forming station Pd is completed, the sheet P is sequentially peeled from the transfer conveyance belt 216 by the discharging device from the leading end thereof, and is guided to the fixing device 217. Finally, the sheet P on which the toner image has been fixed is discharged into a sheet discharge port (not shown).
Is discharged onto the discharge tray 220 from the paper tray.

In the above description, the LSU 227a-
By exposing by scanning with a laser beam at 227d, optical writing to the photosensitive drums 222a to 222d is performed. However, a writing optical system (LED head) including a light emitting diode array and an imaging lens array may be used instead of the LSU. LED head is compared with LSU,
The size is small and there are no moving parts and there is no sound. Therefore, it can be suitably used in an image forming apparatus such as a digital color copying machine of a tandem system (a system in which a plurality of photosensitive drums are arranged in parallel) which requires a plurality of optical writing units.

A sheet conveying apparatus according to an embodiment of the present invention will be described with reference to FIGS.

As shown in FIG.
Are the first registration roller 11 and the second registration roller 12
The rotation shaft 12a of the second registration roller 12 is rotatably supported by the frame 13 of the apparatus main body.
The first registration roller 11 is provided so as to be able to approach and separate from the second registration roller 12.

The rotating shaft 11 of the first registration roller 11
a is inserted into the insertion hole of the registration roller support 14 and is rotatably supported by the shaft. This registration roller support 1
4 has an engagement groove 14a which engages with the frame 13 and is connected to the rotation shaft 11a of the first registration roller 11 and the rotation shaft 12a of the second registration roller 12 (the direction of arrow A in FIG. 2). ) Is slidably engaged.

A rotating shaft 12a of the second registration roller 12 is rotatably inserted into the registration roller support 14, and has an elongated hole 14b having a length larger than the sliding amount of the registration roller support 14. A manual knob 15, which is inserted loosely into the elongated hole 14b and rotates the second registration roller 12 manually at one end of the rotary shaft 12a when a jam occurs, is mounted.

Then, one end of a spring 16 that pulls the first registration roller 11 and presses against the second registration roller 12 is engaged with the lower end of the elongated hole 14b of the registration roller support 14, and the other end of the spring 16 is connected to the device. Locked to the body. The spring 16 and the registration roller support 14 constitute pressing means for pressing the first registration roller 11 to the second registration roller 12, and the pressing means are provided at both ends of the rotation shaft 11 a of the first registration roller 11. The first registration roller 11 is pulled toward the second registration roller 12 by the urging force of the spring 16 and is pressed against the second registration roller 12.

Next, a method of separating the first registration roller 11 from the second registration roller 12 will be described with reference to FIGS.
Is moved upward in the drawing against the pulling force toward the second registration roller 12 due to the urging force of the first registration roller 11 so that the engagement between the engagement groove 14a and the frame 13 is released.
And the second registration roller 12 are separated from each other.

At this time, the rotating shaft 12a of the second registration roller 12 is formed by the elongated hole 14b of the registration roller support 14.
Allow the registration roller support 14 to move upward without hindering the movement of the registration roller support 14.

After the registration roller support 14 is moved upward, the rotation shaft 11a of the first registration roller 11 is removed from the registration roller support 14 so that the first registration roller 11 is
4, and only the registration roller support 14 from which the first registration roller 11 has been removed is engaged with the frame 13.

As described above, the first registration roller 11 can be separated from and removed from the second registration roller 12 without removing the spring 16.
The first registration roller 11 can be stably pressed against the second registration roller 12 with a predetermined pressing force while preventing the spring 16 from being lost or falling into the apparatus main body.

In addition, the registration roller support 14 is mounted on the rotation shaft 1 so that the rotation shaft 12a of the second registration roller 12 does not interfere when the registration roller support 14 moves.
Since the elongated hole 14b through which the second roller 2a is inserted is formed, the registration roller support 14 can be moved without lowering the strength of the registration roller support 14 against the urging force (pulling force) of the spring 16. I have.

In the above embodiment, the length of the resist roller support 14 is longer than the amount of movement of the resist roller support 14 so that the rotation shaft 12a of the second resist roller 12 does not hinder the movement of the resist roller support 14. A hole 14b is formed, and the rotating shaft 12a of the second registration roller 12 is inserted through the elongated hole 14b. A portion for inserting and supporting the rotating shaft 11a of the first registration roller 11 and a portion for attaching the spring 16 are formed. The registration roller support 14 may be formed by being connected by a curved arm having a shape bypassing the rotation shaft 12a of the registration rollers 2.

[0049]

According to the present invention, the first rotating body is removed.
The rotor support from the device frame
Is disengaged against the urging force of
Remove the rotating body support from the support
The spring can be removed.
In addition, it is possible to prevent the spring from being lost or falling into the device .

[0050]

[0051]

[Brief description of the drawings]

FIG. 1 is a front cross-sectional view of a digital color copying machine using a paper transport device of the present invention.

FIG. 2 is a perspective view illustrating an embodiment of a sheet conveying device of the present invention.

FIG. 3 is a front view showing a state in which a first registration roller is pressed against a second registration roller in FIG. 2;

FIG. 4 is a side sectional view showing a state where a first registration roller is pressed against a second registration roller in FIG. 2;

FIG. 5 is a front view showing a state in which a first registration roller is separated from a second registration roller in FIG. 2;

FIG. 6 is a side sectional view showing a state in which a first registration roller is separated from a second registration roller in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier main body 11 1st registration roller 11a Rotation shaft 12 2nd registration roller 12a Rotation shaft 13 Frame 14 Registration roller support 14b Slot 15 Manual knob 16 Spring

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsutaka Okazaki 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Fumio Shimazu 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp shares In-company (72) Inventor Kiyoshi Toizumi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-63-60859 (JP, A) JP-A-4-159994 (JP, A) ) JP-A 2-33921 (JP, U) JP-A 60-36945 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B65H 5/06

Claims (3)

(57) [Claims] A first rotator and a second rotator that are pressed against each other to form a nip portion, and the nip portion grips and transports the sheet; A rotation shaft that is inserted into the rotation shaft and rotatably supports the rotation shaft, the rotation shaft being slidably engaged with the device frame in a direction of pressing the first rotating body against the second rotating body; A body support, one end of which is attached to the rotator support, and the other end of which is attached to the apparatus frame, respectively, so that the first rotator is moved in the direction of the second rotator and pressed against each other. A spring for biasing, the rotating body support member resists the biasing force of the spring .
Then, the first rotating body is separated from the second rotating body.
Direction, and release the engagement of the device frame is capable provided without removing the spring, the first
A sheet conveying device configured to be engaged with the apparatus frame in a state where the rotating body is removed. 2. A sheet conveying device for conveying a sheet by pressing a first rotating body and a second rotating body against each other, wherein a rotating shaft of the first rotating body is rotatable and detachable. A rotator support, wherein the rotator support is movably engaged with an apparatus frame rotatably supporting the second rotator; A spring is provided between the rotator support and the device frame for moving and pressing in the direction of the rotator, without removing the spring, the rotator support opposes the urging force of the spring. The first rotating body is
It is provided so as to be disengaged from the apparatus frame in a direction away from the second rotating body, and is configured to be able to remove the first rotating body in the disengaged state. A sheet conveying device. 3. The rotating body supports are provided at both ends of a rotating shaft of the first rotating body, respectively, and the springs are provided on the respective rotating body supports. The sheet transport device according to claim 1, wherein: