JP4703496B2 - Document conveying and reading apparatus, image forming apparatus - Google Patents

Description

  The present invention relates to a reading apparatus that reads an image while conveying a document sheet, and an image forming apparatus such as a copying machine, a facsimile, a printer, and a multi-function machine using these.

  The image reading method employed in the conventional image reading apparatus includes a document fixing / optical system moving method (scanning method) for exposing and scanning a document, and a document moving / optical method for moving the document at a predetermined speed and exposing it. It is well known that there are an analog type used in a general image reading apparatus and a digital type using an image pickup device such as a CCD, which are classified into a system fixing method (sheet through method). Recently, a digital type document movement / optical system fixing method, which is advantageous for reading a large document and performing various image processing thereafter, has been widely adopted.

  Such a document conveying / reading apparatus generally has a configuration in which a document is conveyed by pressing a driven roller driven rubber roller for constituting a document conveying unit. Further, in an image reading apparatus for sheet document conveyance, a space for document conveyance is provided between the contact glass and the white roller or the white plate across the conveyance path. Patent Document 1 discloses an image reading apparatus that cleans dirt with a glass cleaning roller, and Patent Document 2 discloses an image reading apparatus that controls a white reference plane provided on the glass cleaning roller. Further, Patent Document 3 discloses a brush cleaning device having a large number of air holes in a rotating core rod.

JP 2002-368963 A JP 2002-290686 A JP-A-6-324610

  In recent years, a contact reading sensor has come to be used as an image reading unit. However, since the depth of focus of the contact reading sensor is shallow, when the image information of the sheet document is read by the contact reading sensor, it is used as a sheet document. When wrinkles such as waviness are present, the position of the original reading surface is moved away from the contact glass surface, which may cause image blur due to a focus position shift, which may cause deterioration of the read image. . In addition, when the central conveyance speed of the sheet original is faster than the peripheral conveyance speed, a phenomenon that the rear periphery of the sheet original gradually approaches the center side may occur, and wavy wrinkles may occur at the rear of the original.

The present invention takes into consideration that if the reading position changes during document conveyance, the read image will be reduced. Therefore, the document wrinkle is reduced, the document conveyance performance is not impaired, and an accurate image can be obtained. The purpose is to enable reading.

According to a first aspect of the present invention, there is provided a document conveying / reading apparatus, a document conveying unit that conveys a sheet document, an illumination unit that irradiates light to the sheet document conveyed by the conveying unit, and an irradiation unit that emits light. An image forming lens system for converging light reflected by a sheet original and a reading device for reading light converged by the image forming lens system. The brush roller has a flocked brush on the outer peripheral surface thereof, and at least a part of the flocked brush is rotated when the brush roller is driven to rotate in a direction of conveying a document by a driving source. Ri Na arranged as to contact the contact glass surface of the image reading unit, a brush length of the bristles brush of the brush roller, be symmetrical with respect to the document conveyance center of the document conveying means Together, it characterized that you have long toward the peripheral side of the document conveying means. In other words, if the reading position changes during document conveyance, the read image will be degraded. Therefore, by pressing the document against the contact glass, document wrinkles are reduced and document conveyance performance is not impaired. And accurate reading is possible. In addition, when the central conveyance speed of the sheet original is faster than the peripheral conveyance speed, a phenomenon in which the rear periphery of the sheet original gradually approaches the central side is prevented, thereby preventing wrinkles from occurring. In the present invention, the term “lens system” refers to a concept including not only a plurality of lenses but also a single lens. On the other hand, the term “lens” may mean a concept including a lens system.

A document conveying / reading apparatus according to a second aspect of the present invention includes a document conveying unit that conveys a sheet document, an illumination unit that irradiates light to the sheet document conveyed by the conveying unit, and an irradiation unit that emits light from the irradiation unit. an imaging lens system for converging the light reflected by the document sheet, in document feeding and reading apparatus having a reading means for reading the light is converged by said imaging lens system, the reading position of the image reading unit across the document conveying path The brush roller has a flocked brush on the outer peripheral surface thereof, and at least a part of the flocked brush is rotated when the brush roller is driven to rotate in a direction of conveying a document by a driving source. will be placed in contact with the contact glass surface of the image reading unit, as well as symmetrically with respect to the document conveyance center of the front Kihara draft conveying means, towards the periphery side of the document conveying means Nitsu Wherein the Te are as waist of the flocked brush increases. In other words, when the sheet document central conveyance speed is higher than the peripheral conveyance speed, a phenomenon in which the rear periphery of the sheet original gradually approaches the center side is prevented, thereby preventing wrinkles from occurring.

A document conveying / reading apparatus according to a third aspect of the present invention is the document conveying / reading apparatus according to the first or second aspect, wherein a peripheral speed at a diameter of the brush roller in contact with the original surface of the sheet original is set to the original of the sheet original. It is characterized in that it is faster than the conveying speed. In other words, by pressing the original against the contact glass, the wrinkle of the original is reduced, and accurate reading is possible without impairing the original transportability.

A document conveying / reading apparatus according to a fourth aspect of the present invention is the document conveying / reading apparatus according to any one of the first to third aspects, wherein a belt-shaped reference white reading surface is formed in the axial direction on the outer periphery of the rotating cored bar of the brush roller. It is characterized by having. In other words, the original is pressed against the contact glass to reduce the wrinkle of the original, and the shading correction can be performed to enable accurate reading.

A document conveying / reading apparatus according to a fifth aspect of the present invention is the document conveying / reading apparatus according to the fourth aspect, wherein a detection unit that detects a position of the reference white reading surface and a reading that takes a timing of reading the reference white reading surface. And a timing control unit, wherein the reading timing control unit performs white shading correction before reading the document surface of the sheet document. By performing reading timing control that takes the reading timing of the reference white reading surface, white shading correction can be reliably executed.

An image forming apparatus according to the present invention includes the document conveyance reading device according to any one of claims 1 to 5 .

  According to the present invention, in order to prevent the reading position from being changed during the document conveyance to cause a decrease in the read image, the document wrinkles are reduced, and the document conveyance performance is not deteriorated and accurate reading can be performed. it can.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a schematic configuration of a digital copying machine having a document conveying system that is an embodiment of a document conveying / reading apparatus according to the present invention and an image forming apparatus using the same. The illustrated apparatus is configured by mounting a document conveying / reading apparatus 200 on an upper part of an image forming unit 100. The copy sheet serving as the recording medium is discharged from the discharge rollers 21a and 21b on the downstream side of the fixing device 21 in the sheet conveyance direction by the switching mechanism. The copy sheet is discharged backward (in the direction of arrow E) from the discharge roller 21a and forward (in the direction of arrow D) from the discharge roller 21b.

  Here, when a sheet document is inserted with the document surface facing down to the document conveying / reading apparatus 200 (arrow A in the figure), a stepping motor (not shown) is rotated by a detection signal of the size detection sensor 14, and the sheet document is read. Is stopped by the entrance roller 1 and temporarily stops in front of the registration detection sensor 15. After the arbitrarily set waiting time, the stepping motor is rotated again, and the stopped sheet original is in close contact with the white brush roller 4. It is conveyed between the image sensor units 5. After a predetermined pulse count has elapsed after the registration sensor 15 detects the leading edge of the sheet document, the contact image sensor unit 5 starts reading the document surface of the sheet document, and further processes the read image while further processing the sheet document. The conveyance is advanced, and the paper is discharged from the document driving roller 2. The discharged sheet document is discharged backward (arrow B in the figure) or upward (arrow C in the figure) by the switching mechanism. In the figure, reference numeral 16 denotes a paper discharge detection sensor.

  The driving of the document conveyance is transmitted to each conveyance roller (the document insertion roller 1 and the document driving roller 2) by a scanner motor (for example, a stepping motor) via a timing belt drive transmission means. The document insertion roller 1 is driven and controlled via a conveyance clutch. Further, the driving force is transmitted to the document discharge roller 3 through a gear and a timing belt. Each transport roller is configured by providing a rubber roller on a cored bar in a comb bar shape.

  FIG. 2 is a perspective view showing the contact image sensor unit 5 provided in the document conveyance reading apparatus 200 of FIG. Reference numeral 203 in the figure denotes a contact reading sensor, which has a contact glass 202 that comes into contact with an original, and illuminates a light that irradiates the sheet original 201 and a light that is irradiated from the illuminating means and reflected from the sheet original. The light converged by the image lens and the imaging lens is imaged on the light receiving surface of the image sensor of the contact reading sensor 5 and subjected to photoelectric conversion. A brush roller 4 that is rotationally driven in the document conveyance direction is disposed above the contact reading sensor 5, and the hair tip of the brush roller 4 is in contact with the upper surface of the contact glass 202 and is slightly bent. It is arranged in a state.

  The core of the brush roller 4 is a hollow pipe 204, and a vent hole 206 is formed on the outer peripheral surface thereof, and a suction fan (not shown) is formed with both sides of the hollow pipe 204 or one side of the hollow pipe 204 being closed. Thus, suction is performed in the direction of arrow F in the figure. As described above, dust on the sheet original 201 and the contact glass 202 can be sucked by sucking air from the outer peripheral surface of the brush roller 4, so that an abnormal image such as black streaks due to erroneous reading due to dust or the like can be sucked. Can be prevented.

  In the example of FIG. 2, the white flocking brush 205 is placed on the outer peripheral surface of the hollow pipe 204 at the document conveyance center (the part intersecting with the rearward extension of the arrow A in the figure, that is, the area indicated by the arrow A1 in the figure). Symmetrically right-handed and spirally wound left-handed. The rotation direction H of the brush roller 4 is the document conveying direction A, and the winding is arranged so that the brush contact position in contact with the sheet document 201 is directed outward from the document center.

  By adopting such a configuration, even when the sheet original 201 is wavy, by pressing with the brush roller 4, the wavy is forcibly pressed to prevent the occurrence and reduce image blur due to the floating of the original. Further, a force that spreads the sheet original 201 in the G direction in the drawing acts, so that it is possible to prevent the occurrence of undulation in the main scanning direction caused by the rear portion of the sheet original 201 approaching the center side, and image blurring and image in the sub-scanning direction Bending can also be prevented. In this embodiment, by providing the flocking brushes 205 at intervals, the wrinkling wrinkles can easily escape to the left and right of the sheet original 201 (in the direction orthogonal to the arrow A in FIG. 1 or outside in the same intersecting direction).

  FIG. 3 is a conceptual diagram illustrating a brush roller according to a second embodiment of the present invention. The brush roller 4 of the present embodiment is configured such that the length of the flocked brush 205 becomes longer from the center toward both sides, and the pressing force on the sheet document is stronger at the peripheral portion than at the central portion. I am doing so. Therefore, a force that spreads the sheet document in the direction of arrow G in FIG. 2 acts to prevent the back of the sheet document from moving toward the center, preventing waviness in the main scanning direction, and image blurring and image bending in the sub-scanning direction. Can be prevented.

  FIG. 4 is a conceptual diagram illustrating a brush roller according to a third embodiment of the present invention. The brush roller 4 according to the present embodiment has the thickness, material, density, and the like of the brush material changed so that the waist of the flocked brush 205 becomes stronger from the center toward both sides. The peripheral part is stronger than the central part. With this configuration, a force that spreads the document in the direction of arrow G in FIG. 2 acts, so that the back of the sheet document can be prevented from wobbling in the main scanning direction, and image blurring and sub-scanning can be prevented. It is also possible to prevent image bending in the direction.

  FIG. 5 is a conceptual cross-sectional view showing a brush roller of Example 4 of the present invention. The brush roller 4 of the present embodiment has a belt-shaped reference white reading surface 501 in the axial direction on the outer periphery of the core metal 204 of the brush roller 4, and a detection unit that detects the position of the reference white reading surface 501 In the apparatus of FIG. 1, control can be performed so that the contact reading sensor 5 and the reference white reading surface 11 stop at a facing position. Before the leading edge of the sheet original reaches the image reading position, the reference white reading surface 501 of the brush roller 4 is read, and the sensitivity unevenness, the light intensity unevenness, etc. of the contact reading sensor 5 are corrected by the read values, that is, after shading. The brush roller 4 is turned. The detection means for detecting the position of the reference white reading surface 11 may be reflection detection or transmission detection, but is not limited to such detection. As shown in FIG. 5, the reference white reading surface in this embodiment is a white reference plate 501 in which a white sheet is attached to the surface of foam rubber on the core metal 204 of the brush roller 4 from the upper surface of the contact glass 202. For example, it is provided so as to be at a position separated by about 0.5 mm.

1 is a cross-sectional view of a schematic configuration of a document copying and reading apparatus according to the present invention and a digital copying machine having a sheet document conveying system that is an embodiment of an image forming apparatus using the same. 1 is a perspective view showing a contact reading sensor provided in the document conveyance reading apparatus of FIG. The conceptual diagram which shows the brush roller of Example 2 of this invention. The conceptual diagram which shows the brush roller of Example 3 of this invention Conceptual sectional view showing a brush roller of Example 4 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Document insertion roller 2 Document drive roller 3 Document discharge roller 4 Brush roller 5 Contact image sensor part 14 Size detection sensor 15 Registration detection sensor 16 Paper discharge detection sensor 21 Fixing device 21a, 21b Discharge roller 100 Image forming part 200 Document conveyance reading Device 201 Sheet original 202 Contact glass 203 Contact reading sensor 204 Hollow pipe 205 Flocking brush 206 Vent hole 501 Reference white reading surface

Claims (6)

An original conveying means for conveying a sheet original, an illuminating means for irradiating light to the sheet original conveyed by the conveying means, and an imaging lens system for converging the light emitted from the irradiating means and reflected by the sheet original; In the document conveying and reading apparatus having reading means for reading the light converged by the imaging lens system,
A brush roller disposed opposite to the reading position of the image reading unit across the document conveyance path is provided. The brush roller has a flocking brush on the outer peripheral surface thereof, and the brush roller is rotated in the direction of document conveyance by a driving source. Ri at least part of said flocked brush when driving the name and placed in contact with the contact glass surface of the image reading unit,
A brush length of the bristles brush of the brush roller, as well as symmetrically with respect to the document conveyance center of the document conveying means, the document feeding and reading apparatus characterized that you have long toward the peripheral side of the document conveying means . An original conveying means for conveying a sheet original, an illuminating means for irradiating light to the sheet original conveyed by the conveying means, and an imaging lens system for converging the light emitted from the irradiating means and reflected by the sheet original; In the document conveying and reading apparatus having reading means for reading the light converged by the imaging lens system ,
A brush roller disposed opposite to the reading position of the image reading unit across the document conveyance path is provided. The brush roller has a flocking brush on the outer peripheral surface thereof, and the brush roller is rotated in the direction of document conveyance by a driving source. When driving, it is arranged so that at least a part of the flocking brush is in contact with the contact glass surface of the image reading unit,
While symmetrically about the document conveyance center of the front Kihara draft conveying means, the document feeding and reading apparatus, wherein said that the waist of the flocked brush are set to be stronger toward the periphery side of the document conveying means. 3. The document conveying / reading apparatus according to claim 1, wherein a peripheral speed at a diameter of the brush roller contacting a document surface of the sheet document is set to be faster than a document conveying speed of the sheet document. Document conveying and reading apparatus. In any of the document feeding and reading apparatus of claims 1 to 3, the rotary core metal outer periphery of the brush roller, the document feeding and reading device, characterized in that it has a strip-shaped reference white read surface in the axial direction. 5. The document conveying / reading apparatus according to claim 4 , further comprising: a detecting unit that detects a position of the reference white reading surface; and a reading timing control unit that takes a reading timing of the reference white reading surface. A document conveying / reading apparatus that performs white shading correction before reading a document surface of the sheet document . An image forming apparatus characterized by comprising any of the document feeding and reading apparatus of claims 1 5.