JP2004072739A - Original reader and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an exposure window for permeating light from an original which passes an exposure position from getting dirty in an original reader for reading images on a moving original. <P>SOLUTION: A cleaning means is contacted to a rotator of a feeding means for feeding the original to the exposure position, thereby cleaning the rotator. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a document reading device and an image forming apparatus having the document reading device, and more particularly to a document reading device that transports a large number of documents one by one to an exposure position by a document transport device and reads an image of the document passing through the exposure position. And an image forming apparatus having the document reading device.
[0002]
[Prior art]
A document reading device that transports a document to an exposure position by a document transport device and reads an image of the document passing through the exposure position is widely used. In such a document reading apparatus, an exposure window is provided at the exposure position, and reflected image light from an illuminated document is introduced into reading means through the exposure window to perform reading, and reading is performed while the document is being conveyed.
[0003]
[Problems to be solved by the invention]
The exposure window is formed of a transparent glass plate, but the glass plate is in contact with or close to the document in reading, so that paper dust and the like are easily attached and stained.
[0004]
There is a problem that the stain on the glass plate has an adverse effect on the image quality of the reproduced image. Japanese Patent Application Laid-Open No. 10-133299 proposes to transport and read an original without bringing the original into contact with the glass plate in order to prevent the glass plate from being stained. However, the dirt prevention means as disclosed in the above-mentioned publication is insufficient and cannot prevent the dirt such as paper dust from adhering to the glass plate and impairing the image quality.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problem in a document reading apparatus, and to provide a document reading apparatus capable of always reproducing a clear image and an image forming apparatus having such a document reading apparatus. The purpose is to:
[0006]
[Means for Solving the Problems]
The above object of the present invention is achieved by any one of the following (1) to (11).
(1) a paper feed tray for loading documents,
Sending means for feeding a document on the paper feed tray,
Separating means for separating and transporting the document fed from the sending means,
A driving roller, and a registration roller having a driven roller made of a material having a larger electrostatic attraction force than the driving roller, and conveying the document separated by the separation unit to an exposure position;
An exposure window that transmits image light from a document passing through the exposure position,
Reading means for reading an image of a document through the exposure window and converting the image into an electric signal;
A document reading device provided with cleaning means for cleaning by contacting the driven roller.
(2) The document reading apparatus according to (1), wherein the cleaning unit is made of a material having an electrostatic attraction force equal to or greater than the electrostatic attraction force of the driven roller.
(3) The document reading device according to (1) or (2), wherein the cleaning unit is provided at a position where the document reading device can be opened.
(4) a paper feed tray for loading documents,
Sending means for feeding a document on the paper feed tray,
Separating means for separating and transporting the document fed from the sending means,
A registration roller that transports the document separated by the separation unit to an exposure position,
An exposure window that transmits image light from a document passing through the exposure position,
Reading means for reading an image of a document through the exposure window and converting the image into an electric signal;
A document reading device provided with a cleaning means provided at a place where the document reading device can be opened and in contact with the registration roller for cleaning.
(5) The document reading apparatus according to (4), wherein the registration roller includes a driving roller and a driven roller, and the cleaning unit performs cleaning by contacting the driven roller.
(6) The document reading device according to any one of (1) to (5), wherein the cleaning unit is detachably attached.
(7) The registration roller according to (1) to (6), wherein the registration roller is disposed so as to include substantially the same position with respect to the feeding means in a direction perpendicular to the document conveying direction. The document reading device according to any one of the above.
(8) The registration roller according to any one of (1) to (7), wherein the registration roller is disposed so as to include substantially the same position with respect to the separation unit in a direction perpendicular to the document conveying direction. The document reading device according to any one of the above.
(9) The document reading apparatus according to any one of (1) to (3) and (5), wherein the driving roller is a lower roller, and the driven roller is an upper roller.
(10) The driving roller is made of a material having a large coefficient of friction, and the driven roller is made of a material having a small coefficient of friction, wherein (1) to (3), (5), and (9). The document reading device according to any one of the above.
(11) An image forming apparatus comprising the document reading device according to any one of (1) to (10).
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
An original reading apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of a portion of a document reading device of an image forming apparatus according to an embodiment of the present invention.
[0008]
The document reading device has a document conveying device 2 and a reading unit, and the document conveying device 2 is attached to a machine frame 1 of the image forming apparatus as shown in the figure. A part of the document feeder 2 is provided with a sheet feeding tray 3 which is a stacking unit for stacking the documents P in a state inclined slightly in the sheet feeding direction.
[0009]
A pick-up roller 4 is provided as feeding means for feeding paper from the uppermost document P provided on the paper feed tray 3. A pressing plate 5 for pressing the document P against the pickup roller 4 is provided so that the leading end of the document P comes into contact with the pickup roller 4 reliably.
[0010]
The separation roller 6 and the separating roller 7 serving as separation means for separating and transporting the document P fed by the pickup roller 4 into one sheet, and the transport roller for temporarily stopping the document P transported from the separation roller 6 and transporting the same. A pair of registration rollers 8 and 9 are provided. An outer frame 201 of the document feeder 2 is provided so as to be openable upward about the shaft 2A, and a cleaning member 202 as a cleaning unit is provided inside the outer frame 201 by a mounting member 203. The cleaning member 202 always contacts the driven roller 8 of the registration roller to clean the driven roller 8. A transport path 10 is provided downstream of the registration rollers 8 and 9, and a switching guide member 12 is provided downstream thereof. A two-sided conveyance path is formed downstream of the conveyance path 10, and the two-sided conveyance path is provided with reversible rollers 31A and 31B that can be forwardly and reversely rotated to convey rightward and reverse and convey leftward. Have been.
[0011]
The reversing roller 31A is in contact with the reversing roller 31B when the document P is transported, but is configured so that the two documents P can be separated from each other at an interval that allows the two documents P to be rubbed against each other. The reversing rollers 31A and 31B reverse the rotation direction when the rear end of the document P reaches the vicinity of the roller, and convey the document P conveyed rightward to the left. The switching guide member 11 having two arms is located at a position indicated by a dashed line when the document P is guided from the registration rollers 8 and 9 to the double-sided conveyance path. Is moved to the position shown by the solid line. The document P is transported to the exposure position R by providing a pair of transport rollers 21 and 22, and the document P transported to the exposure position R is further sandwiched between the platen roller 23 and the transparent slit glass 24 forming the exposure window. It is configured to be transported. Irradiation light is applied to the document P passing through the exposure position by the irradiation lamp 25, and reflected light from the document is reflected by the mirror 26 and guided to the reading element T, which is a reading means including a CCD, via the lens Q. The data is converted into an electric signal by the reading element T and read. The illumination lamp 25, the mirror 26, the lens Q and the reading element T constitute a reading unit of the document reading device.
[0012]
A switching guide member 28 for switching the document P having passed through the exposure position from the transport path 27 by a pair of transport rollers 14 and 29 and transporting the original P to the discharge transport path 30 or to the double-side transport path again. Is rotatably provided on the shaft of the reversing roller 31A. The document P guided to the discharge conveyance path 30 is discharged to a discharge section 32 by a discharge roller 31 provided opposite to the reversing roller 31A.
[0013]
The document feeder according to the present embodiment is provided with sensors S1, S2, and S3 for detecting passage of a document.
[0014]
The sensor S1 is provided immediately upstream of the registration rollers 8 and 9, and stops the rotation of the separation roller 6 by detecting the leading edge of the document. The stop time of the separation roller 6 is set such that a document loop is formed upstream of the registration rollers 8 and 9. The sensor S1 also detects the passage of the rear end of the document. The length of the document is detected from the time from the restart of the registration rollers 8 and 9 to the detection of the passage of the rear end. Further, the time for stopping the reversing rollers 31A and 31B is determined from the detection of the rear end of the document. The sensor S2 detects the leading edge and the trailing edge of the document, and determines the reading start time and the reading end time of the document. The sensor S3 is a sensor that detects the discharge of the document P, and also has a function of detecting a jam.
[0015]
In the document feeder 2, the pick-up roller 4, the separation roller 6, the separating roller 7, the registration rollers 8, 9, the transfer rollers 21, 22 and the like for transferring the document from the sheet feed tray 3 to the slit glass 24 constitute a transfer means. I do. Note that a belt stretched over rollers may be used as a part of the transporting means.
[0016]
(1) The first document P sent out by the double-sided reading pickup roller 4 is conveyed by the separation roller 6 and conveyed between the registration rollers 8 and 9, and then detected by the sensor S1 and temporarily stopped. Then, the conveyance of the document P is started by the rotation of the registration rollers 8 and 9.
[0017]
The switching guide member 12 is set at the position indicated by the one-dot chain line and is switched to the double-sided conveyance path side when reading double-sided originals, and guides the document P to the double-sided conveyance path. The document P conveyed by the registration rollers 8 and 9 is conveyed to the reversing rollers 31A and 31B through the two-sided conveyance path, conveyed rightward by the reversing rollers 31A and 31B, and held at the rear end by these rollers. In this state, the reversing rollers 31A and 31B stop. When the document P is held by the reversing rollers 31A and 31B, the first page of the document P is on the lower side, and the second page is on the upper side.
[0018]
Next, the reversing rollers 31A and 31B are reversed and rotated in the direction of the dotted arrow, and the conveyance of the document P is started. At this time, the switching guide member 11 has been moved to the position shown by the solid line, the transport path 20 is opened, the document P is transported to the transport path 20, and transported by the transport rollers 21 and 22, and the leading end of the document P is Immediately after the detection by S2, the conveyance by the conveyance rollers 21 and 22 temporarily stops.
[0019]
Next, the document P is transported to the exposure position R when the transport rollers 21 and 22 start rotating, and transported by the platen roller 23. Reading of the back side of the document P, which is guided by the slit glass 24 and moves, that is, the second page is performed.
[0020]
The document P that has passed the exposure position R is guided to the double-sided conveyance path by the switching guide member 28 located at a position indicated by a dashed line, and is conveyed again to the reversing unit 18 by the reversing rollers 31A and 31. Here, the second page of the document P is on the lower side, the first page is on the upper side, and the document P is stopped in a state where the rear end of the document P is sandwiched between the reversing rollers 31A and 31B.
[0021]
Next, the reversing rollers 31A and 31B start rotating in the directions indicated by the dotted arrows, and convey the document P. In the process of transporting the first document P, the second document P on the paper feed tray 3 is fed by the pickup roller 4 and temporarily stopped by the registration rollers 8 and 9. The first original P is transported by the reversing rollers 31A and 31B in the duplex transport path, is transported in the transport path 20 opened by the switching guide member 11, and immediately after the leading edge of the original is detected by the sensor S2. Stop once. The conveyance of the document P is started by the rotation of the conveyance rollers 21 and 22, and the stopped second document P is guided by the switching guide member 12 by the registration rollers 8 and 9 and is conveyed from the conveyance path 10. It is transported to the road 110. When the conveyance rollers 21 and 22 rotate and start conveyance, the reversing rollers 31A and 31B are separated from each other, and the holding of the document P is released.
[0022]
Here, the trailing edge of the first document P remains at the position of the reversing rollers 31A and 31B, but the trailing edge of the first document P and the leading edge of the second document P are in the double-sided conveyance path. Are conveyed while contacting each other. The switching guide member 11 guides the original P at the position indicated by the solid line at the stage of guiding the leading end of the first original to the transport path 20, but is capable of swinging after the first original has passed. As a result, the passage of the preceding first document P to the left and the passage of the succeeding second document P below are permitted.
[0023]
As described above, the leading edge of the second document P is conveyed to the position of the reversing rollers 31A and 31B, and the reversing rollers 31A and 31B are moved even if the rear end of the first document P is within the reversing rollers 31A and 31B. Since they are separated from each other, the leading edge of the second document P is smoothly conveyed to the reversing unit 18 while the leading edge of the second document P is in contact with the trailing edge of the first document P.
[0024]
Next, the first document P transported by the transport rollers 21 and 22 is transported to the exposure position R, and the first page thereof is irradiated and read. The document P from which the image of the first page has been read is guided and conveyed to the discharge path 30 by the conveying rollers 14 and 29, and the first page of the first document P is conveyed by the reversing roller 31 </ b> A and the discharge roller 31. Is discharged downward to the paper discharge unit 32.
[0025]
(2) Sheets are fed by the pickup roller 4 from the first sheet of the original P placed and placed on one side, and the originals P are sequentially conveyed one by one as described above. , 9 temporarily stop. Next, the resist rollers 8 and 9 are conveyed from the conveying path 10 to the conveying path 20 by the rotation start.
[0026]
Next, the document P is transported from the transport path 20 by the transport rollers 21 and 22 and passes through the exposure position R. The document P that has passed the exposure position R is conveyed to the paper discharge conveyance path 30 by the conveyance rollers 14 and 29, and the image of the first document P is discharged by the reversing roller 31A and the paper discharge roller 31C with the image on the lower side. The paper is discharged to the paper unit 32.
[0027]
By double-sided reading or single-sided reading described above, an image of a document is read, image information is obtained from the obtained electric signal, and based on the image information, an electrophotographic process, that is, charging, exposure, development, transfer and fixing is performed. An image is formed on recording paper through the steps.
[0028]
In the above-described document reading apparatus, when the cleaning is not performed by the cleaning member 202, paper dust easily adheres to the slit glass 24 forming the exposure window. And a cleaning member 202 that is a cleaning unit that cleans the driven roller 8 by contacting the driven roller 8 of the registration roller that is a conveyance roller that forms a part of the conveyance unit that conveys the driven roller 8 to the exposure position R.
[0029]
In the registration rollers 8 and 9, the lower roller is a driving roller 9 connected to a driving motor and is made of rubber, and the upper roller is the driven roller 9 and made of resin.
[0030]
It is desirable that the driven roller 8 be made of a material that is easier to attract paper dust by electrostatic force or the like than the driving roller 9. With this configuration, the paper dust adhered to the driving roller 9 is transferred to the driven roller 8, and the paper dust is removed from the driven roller 8 by the cleaning member 202. The paper dust is removed from P, and the paper dust is prevented from adhering to the slit glass 24. The material of the driven roller 8 is desirably resin, metal, or the like having a small coefficient of friction with the document. The material of the drive roller 9 is preferably rubber or the like having a large friction coefficient. As the cleaning member 202, a malt plane pad, a flocking pad, or the like is desirable. It is desirable to select the material so that the electrostatic attraction force against the paper powder satisfies cleaning member 202 ≧ driven roller 8> drive roller 9.
[0031]
The location where the above-mentioned cleaning means is provided is not limited to the registration rollers 8 and 9. The rotation of the conveyance means upstream of the image reading exposure position R such as the pickup roller 4, the separation roller 6, the separation roller 7, and the conveyance rollers 21 and 22. It is preferable to provide it on any one or more of the bodies, and in particular, it is possible to prevent the slit glass 24 from being stained for a longer time by attaching it to a rotating body near the slit glass 24.
[0032]
The cleaning member 202 is detachably attached and can be replaced periodically or as needed. Further, a cleaning member 202 that is larger than the driven roller 8 may be used to change the contact position with the driven roller 8.
[0033]
Paper dust is particularly generated by the pickup roller 4, the separation roller 6, and the separation roller 7 which send out the original P by the frictional action and separate it into one sheet.
[0034]
As shown in FIG. 2, the position corresponding to the position indicated by L where the pickup roller 4, the separation roller 6, and the separation roller 7 are disposed, that is, substantially the same position in the direction perpendicular to the document conveying direction is included. The registration rollers 8 and 9 are disposed, and by cleaning the registration roller 8 with the cleaning member 202, the paper dust in the portion of the document P where the paper dust is remarkably generated is removed, and the dirt on the slit glass 24 is extremely effectively removed. Could be prevented.
[0035]
【The invention's effect】
The exposure window that transmits the reflected light from the document is prevented from being stained, the image quality is prevented from deteriorating, and image data that can always form a clear image is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a portion of a document reading device of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a plan view of a portion of the document reading apparatus shown in FIG. 1 where a cleaning member is provided.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Machine frame 2 Document feeder 3 Paper feed tray 4 Pickup roller 5 Pressing plate 6 Separation roller 7 Separation roller 8, 9 Registration roller 21, 22 Transport roller 23 Platen roller 201 Outer frame 202 Cleaning member 203 Mounting member R Exposure position T Reading element

Claims (11)

A paper feed tray for loading documents,
Sending means for feeding a document on the paper feed tray,
Separating means for separating and transporting the document fed from the sending means,
A driving roller, and a registration roller having a driven roller made of a material having a larger electrostatic attraction force than the driving roller, and conveying the document separated by the separation unit to an exposure position;
An exposure window that transmits image light from a document passing through the exposure position,
Reading means for reading an image of a document through the exposure window and converting the image into an electric signal;
A document reading device provided with cleaning means for cleaning by contacting the driven roller. 2. The document reading apparatus according to claim 1, wherein the cleaning unit is made of a material having an electrostatic attraction force equal to or greater than an electrostatic attraction force of the driven roller. The document reading device according to claim 1, wherein the cleaning unit is provided at a position where the document reading device can be opened. A paper feed tray for loading documents,
Sending means for feeding a document on the paper feed tray,
Separating means for separating and transporting the document fed from the sending means,
A registration roller that transports the document separated by the separation unit to an exposure position,
An exposure window that transmits image light from a document passing through the exposure position,
Reading means for reading an image of a document through the exposure window and converting the image into an electric signal;
A document reading device provided with a cleaning means provided at a place where the document reading device can be opened and in contact with the registration roller for cleaning. 5. The document reading apparatus according to claim 4, wherein the registration roller includes a driving roller and a driven roller, and the cleaning unit contacts and cleans the driven roller. The document reading apparatus according to claim 1, wherein the cleaning unit is detachably attached. 7. The document according to claim 1, wherein the registration roller is disposed so as to include substantially the same position with respect to the feeding means in a direction perpendicular to the document conveyance direction. Reader. 8. The document according to claim 1, wherein the registration roller is disposed so as to include substantially the same position with respect to the separation unit in a direction perpendicular to the document conveyance direction. Reader. 6. The document reading apparatus according to claim 1, wherein the driving roller is a lower roller, and the driven roller is an upper roller. 10. The document reading apparatus according to claim 1, wherein the driving roller is made of a material having a large coefficient of friction, and the driven roller is made of a material having a small coefficient of friction. . An image forming apparatus comprising the document reading device according to claim 1.

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