JP3594773B2 - Image input device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image input device applied to a facsimile machine, a copying machine, and the like.
[0002]
[Prior art]
FIG. 4 is a block diagram showing an example of a conventional facsimile apparatus. Reference numeral 20 denotes an image reading unit, reference numeral 21 denotes an image reading device that optically reads a document, and reference numeral 22 denotes a document that is moved toward the image reading position of the image reading device 21. A feed roller 23 is a separation roller that separates and conveys the document sent by the feed roller 22 one by one, a reference numeral 24 is an R1 roller that conveys the document sent by the separation roller 23 to the image reading position, and a reference numeral 25 is provided at the image reading position. The contact glass 26 is provided with an R2 roller for discharging the document passing through the image reading position to the outside, and the reference numeral 27 is provided above the contact glass 25 and biases the document conveyed by the R1 roller 24 toward the contact glass 25. FIG.
[0003]
Reference numeral 28 denotes an image recording unit for recording an image on paper in an electrophotographic system; 29, a photosensitive drum; 30, an optical scanning device for scanning the photosensitive drum 29 with a laser beam to form an electrostatic latent image; A developing device for developing the latent image into a toner image; a transfer device 32 for transferring the toner image on the photosensitive drum 29 to paper; a fixing device 33 for fixing the toner image on the paper; 1 shows a cleaning toner magazine integrally provided with a cleaning unit that collects the residue of the above and a toner storage unit that stores the new toner to be supplied to the developing device 31 and the storage unit.
[0004]
35 is a paper feeding unit, 36 is a paper feeding cassette which stores paper therein and is detachable from the facsimile apparatus main body, and 37 is a paper feeding cassette for transporting the paper in the paper feeding cassette 36 to the image recording unit 28 one by one. The paper roller is shown.
[0005]
The facsimile apparatus shown in FIG. 4 mainly includes three units, an image reading unit 20, an image recording unit 28, and a paper feeding unit 35, and a document read by the image reading unit 20 is sent to a transmission destination via a line. The image information received from the other party via the line or the image information of the document read by the image reading unit 20 is recorded on a sheet by the image recording unit 28.
[0006]
By the way, in an image input device such as a facsimile apparatus or a scanner, the original is kept at a certain distance from the contact glass in order to focus on reading the original or to prevent vertical lines from being distorted due to fluttering on the contact glass. There is a need. Therefore, even in an image reading apparatus that requires an accuracy of 0.2 mm to 0.4 mm for focusing, for example, an image reading apparatus using a contact sensor or a reduction optical system of a CCD (charge coupled device), distortion of a vertical line is minimized. In order to achieve this, a white pressure plate for determining the white level is elastically brought into contact with the contact glass, or is elastically arranged with a small gap of about 0.2 mm.
[0007]
[Problems to be solved by the invention]
However, since the white pressure plate is generally made of a member having a high electric resistance, for example, a colored film made of PET material or a resin material, when a document is passed, static electricity is generated due to friction and dust is generated. Adhered, and this dust was recognized as a black dot, and the output was scanned in the sub-scanning direction.
[0008]
For this reason, conventionally, a conductive component is attached to a part of the back side of the white pressure plate, or a conductive member for urging the document separately from the white pressure plate is provided. However, because it is only a part of the back side of the white pressure plate, it is insufficient for removing static electricity, or when a conductive member is provided, it is urged in front of the image reading unit to read the white pressure plate, Dust may be scraped off by the urging portion and adhered to the image reading unit, and black stripes may be generated.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image input apparatus which solves such a problem and prevents an adverse effect on a read image due to dust such as a toner strip or paper dust.
[0010]
[Means for Solving the Problems]
The present invention for solving the above-mentioned problems is characterized in that image reading means arranged below a contact glass, conveying means for conveying a document on the contact glass, and pressing the document on the contact glass, and In an image input apparatus provided with a white pressure plate for determining a white level in an image reading means, the white pressure plate is constituted by a flexible member having conductivity. With such a configuration, the charging of the white pressure plate due to friction with the document can be reduced to a level at which the white pressure plate does not attract dust.
[0011]
Further, the present invention provides an image reading means disposed below a contact glass, a conveying means for conveying a document onto the contact glass, a method for pressing a document onto the contact glass, and a white level discrimination in the image reading means. An image input apparatus provided with a white pressure plate for use in an image processing apparatus, wherein a flexible conductive plate is disposed on a surface of the white pressure plate opposite to a surface facing the contact glass. With such a configuration, even if the white pressure plate is charged by friction, the level of charging of the white pressure plate can be reduced.
[0012]
Further, the invention is characterized in that the white pressure plate is constituted by a member having a resistance value of 10 ¹³ Ω or more. With such a configuration, the white pressure plate can be configured with a member having high whiteness.
[0013]
Further, the invention is characterized in that the flexible conductive plate is brought into close contact with the white pressure plate. With such a configuration, the static electricity generated on the white pressure plate is easily moved to the flexible conductive plate side, so that the static electricity on the white pressure plate can be more effectively removed.
[0014]
Further, the present invention is characterized in that the flexible conductive plate is made of a leaf spring material having a thickness of 0.01 mm to 0.3 mm. With such a configuration, the white pressure plate can return to the initial position even if the flexible conductive plate is displaced during document conveyance, and the rigidity of the white pressure plate does not increase unnecessarily, and the document is attached. The momentum will be stable and lasting.
[0015]
Further, the present invention provides an image reading means disposed below a contact glass, a conveying means for conveying a document onto the contact glass, a method for pressing a document onto the contact glass, and a white level discrimination in the image reading means. An image input device provided with a white pressure plate for use, wherein a conductive thin film is provided on one surface of the white pressure plate opposite to the surface facing the contact glass by any one of conductive coating, sputtering, and vacuum deposition. Features. With such a configuration, the thickness of the white pressure plate is not increased, so that the rigidity of the white pressure plate is not increased more than necessary, and the urging force against the document can be stabilized.
[0016]
Further, the invention is characterized in that the opposite surface of the white pressure plate is grounded. With such a configuration, static electricity on the white pressure plate can be reliably removed.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 is a configuration diagram showing a main part of an apparatus according to a first embodiment of the present invention, wherein 1 is an R1 roller, 2 is an R1 roller that abuts on and is driven by an R1 roller 1, and 3 is a flexible material made of PET material. Reference numeral 4 denotes a contact glass, and reference numeral 5 denotes a contact sensor housing in which a contact image sensor including a light source and an image reading element is housed. The contact glass 4 is mounted on the contact sensor housing 5, and the guide member 3 is cantilevered at the end of the contact glass 4 on the side where the document is fed. Further, 6 is an R2 roller, 7 is an R2 roller which abuts on and is driven by the R2 roller 6, 8 is a white pressure plate which is made of a flexible member and has a white surface for white level discrimination, and 9 is vertically movable. A square pipe that is installed and grounds the flexible conductive plate, 10 is a lower housing of the image input device main body, 11 is an upper housing of the image input device main body that can be opened and closed with respect to the lower housing 10, and 12 is a document. Show.
[0019]
The lower housing 10 is mounted with the R1 roller 1, the contact sensor housing 5 and the R2 roller 6 in this order, with the free end of the guide member 3 facing the R1 roller 1 side. The upper housing 11 is mounted with the R1 roller 2, the white pressure plate 8, the square pipe 9, and the R2 roller 7 in this order. One end of the white pressure plate 8 is fixed to the upper housing 11 between the R1 roller 2 and the square pipe 9, and the other end is fixed to the square pipe 9. When the lower housing 10 and the upper housing 11 are combined, the R1 roller 1 and the R1 roller 2 and the R2 roller 6 and the R2 roller 7 come into contact with each other, and the white pressure plate 8 is positioned above the contact sensor housing 5. Can be At this time, the lower part of the square pipe 9 is the image reading position, and the other end of the white pressure plate 8 is on the image reading position. At this time, the other end of the white pressure plate 8 is placed in contact with the contact glass 4 or provided with a small gap. Further, the document 12 conveyed by the R1 roller 1 is conveyed to the image reading position while being guided by the white pressure plate 8 to the contact glass 4 side.
[0020]
The white pressure plate 8 is made of a conductive flexible member having a resistance value of less than 10 ¹³ Ω, and is grounded via the square pipe 9. In general, it has been found that a member having a resistance value of less than 10 ¹³ Ω has a property of being hardly charged. Conversely, a member having a resistance value of 10 ¹³ Ω or more is a member that is relatively easily charged.
[0021]
Next, the operation will be described.
[0022]
The document 12 set on the document reading apparatus main body is transported by the R1 roller 1, sent to the contact glass 4 by the guide of the guide member 3, and the image of the document 12 is read by the image reading element in the contact sensor housing 5. , R2 roller 6. At this time, the document 12 is conveyed downward by the guide of the white pressure plate 8, and as a result, the document 12 moves so as to rub the contact glass 4. At the same time, the white pressure plate 8 rubs against the document 12 and is frictionally charged. In this case, since the resistance value of the white pressure plate 8 is less than 10 ¹³ Ω, the charge can be reduced to a level at which dust is not adsorbed. . As a result, dust adhering to the document 12 is less likely to be attracted to the white pressure plate 8 by static electricity.
[0023]
By having such a configuration, even if rubbed and the white plate 8 and the document 12 during document transport, since Kuku in charged by static electricity by white pressure plate 8 is electrically conductive, the white plate 8 by electrostatic dust Is prevented from adhering, and image defects such as black stripes can be prevented. Furthermore, since it is grounded via the square pipe 9, static electricity on the white pressure plate 8 can be reliably removed.
[0024]
FIG. 2 is a block diagram showing a main part of an apparatus according to a second embodiment of the present invention. Reference numeral 13 denotes a white pressure plate which is made of a flexible member and has a white surface for white level discrimination, and 14 denotes a white pressure plate. 13 shows a flexible conductive plate adhered to the surface opposite to the surface facing the contact glass 4. The same members as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.
[0025]
The white pressure plate 13 is made of a flexible member having a resistance value of 10 ¹³ Ω or more, and the flexible conductive plate 14 is made of a leaf spring material made of a copper plate, a phosphor bronze plate, a stainless steel plate, or the like. I have. The flexible conductive plate 14 and the white pressure plate 13 are fixed in close contact with each other by bonding or the like. Further, one end of the flexible conductive plate 14 is fixed to the upper housing 11, but the other end is swingable as a free end. When the upper housing 11 is closed, the white pressure plate 13 and The other end of the flexible conductive plate 14 comes into contact with the contact glass 4 and is elastically deformed, so that the white level can be read. At this time, the square pipe 9 contacts the other end of the flexible conductive plate 14.
[0026]
Here, regarding the thickness of the flexible conductive plate 14, when the thickness is small, it is difficult to sufficiently bias the document, and when the thickness is large, the rigidity is increased and the biasing force on the document becomes more than necessary. growing. Then, as a result of an experiment, it was found that a thickness range of 0.01 mm to 0.3 mm was appropriate. Therefore, the thickness of the flexible conductive plate 14 in the present embodiment is set in a range of 0.01 mm to 0.3 mm.
[0027]
Next, the operation will be described.
[0028]
The document 12 set on the document reading apparatus main body is transported by the R1 roller 1, sent to the contact glass 4 by the guide of the guide member 3, and the image of the document 12 is read by the image reading element in the contact sensor housing 5. , R2 roller 6. At this time, the document 12 is pressed downward by the urging of the flexible conductive plate 14, and as a result, the document 12 moves so as to rub the contact glass 4. At the same time, the white pressure plate 13 rubs against the document 12 to generate static electricity. However, since the flexible conductive plate 14 attached to the white pressure plate 13 has conductivity, the static electricity is generated by the flexible conductive plate 14 and the square pipe 9. Therefore, the dust adhering to the document 12 is not easily attracted to the white pressure plate 13 because it is discharged through the white pressure plate 13.
[0029]
With this configuration, the static electricity of the white pressure plate 13 is removed, so that dust is prevented from adhering to the white pressure plate 13, and it is possible to prevent image defects such as black stripes. Further, since the white pressure plate 13 and the flexible conductive plate 14 are in close contact with each other, the charge level of the white pressure plate 13 can be reliably reduced. Further, since the flexible conductive plate 14 is made of a leaf spring material, the white pressure plate 13 can return to the initial position even if the flexible conductive plate 14 is displaced during document transport, and the original 12 Becomes stable and continuous. In addition, since a member having a resistance value of 10 ¹³ Ω or more can easily form a member having a higher white level than a member having a resistance value of less than 10 ¹³ Ω, accurate white level detection can be performed.
[0030]
In addition, if a flexible conductive plate made of a material having better conductivity than the white pressure plate 8 is attached to the opposite surface of the white pressure plate 8 in the device of the first embodiment, the static electricity on the white pressure plate 8 can be more reliably formed. Can be prevented from occurring.
[0031]
If the white pressure plate 13 has a resiliency enough to appropriately bias the original, the white pressure plate 13 is fixed to one end of the flexible conductive plate 14 and the other end of the flexible conductive plate 14 is connected to a square pipe. 9 so that the other end of the white pressure plate 13 can be swung as a free end. When the upper housing 11 is closed and the other end of the white pressure plate 13 abuts on the contact glass 4 while being elastically deformed, and the white level can be read, the white pressure plate 13 and the flexible conductive plate are connected. You may comprise so that the board | plate 14 may be stuck.
[0032]
FIG. 3 is a configuration diagram showing a main part of an apparatus according to a third embodiment of the present invention. Reference numeral 15 denotes a conductive thin film formed on the opposite surface of the white pressure plate 13. The device according to the second embodiment has a flexible conductive plate 14 made of a leaf spring material adhered to the opposite surface of the white pressure plate 13, whereas the device according to the third embodiment has Instead of the flexible conductive plate 14, a conductive thin film 15 is formed by conductive coating, sputtering, vacuum deposition, or the like.
[0033]
With such a configuration, it is possible to prevent dust from adhering to the white pressure plate 13 and to urge the original 12 by the white pressure plate 13 with an appropriate force without excessively increasing the force for urging the contact glass 4. That is, it is possible to reduce the occurrence of skew and jam during document conveyance.
[0034]
The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments. For example, in the above-described embodiment, an image input apparatus using a contact sensor has been described. However, similar effects can be obtained by applying the present invention to an image input apparatus using a reduction optical system using a CCD as shown in FIG. Can be
[0035]
【The invention's effect】
According to the present invention configured as described above, the charging of the white pressure plate can be reduced with a simple configuration, so that dust adhering to the document is less likely to be attracted to the white pressure plate. The occurrence of black streaks in the image is prevented.
[0036]
Further, since the white pressure plate is formed of a member having a resistance of 10 ¹³ Ω or more, a member having a high white level can be applied to the white pressure plate. Further, since the flexible conductive plate is formed of a leaf spring material having a thickness of 0.01 mm to 0.3 mm, the white pressure plate returns to the initial position even if the flexible conductive plate is displaced during document conveyance. And the force for urging the document is stabilized and maintained.
[0037]
In addition, by forming a conductive thin film on the opposite surface of the white pressure plate, the force of urging the original by the white pressure plate against the contact glass can be set to an appropriate force without excessively increasing the skew during document conveyance. And occurrence of jams can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a main part of an apparatus according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram illustrating a main part of an apparatus according to a second embodiment of the present invention.
FIG. 3 is a configuration diagram showing a main part of an apparatus according to a third embodiment of the present invention.
FIG. 4 is a configuration diagram showing an example of a conventional facsimile machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... R1 roller, 2 ... R1 roller, 3 ... Guide member, 4 ... Contact glass, 5 ... Adhesion sensor housing, 6 ... R2 roller, 7 ... R2 roller, 8, 13 ... White pressure plate, 9 ... Square pipe, 10 ... lower housing, 11 ... upper housing, 12 ... manuscript, 14 ... flexible conductive plate, 15 ... conductive thin film.

Claims (6)

Image reading means disposed below the contact glass, conveying means for conveying a document onto the contact glass, and a white pressure plate for pressing the document onto the contact glass, and for determining the white level in the image reading means; In the image input device provided with
Grounding means is provided movably up and down on a portion of the apparatus body opposite to the document reading position, and has a grounding means for constantly contacting and grounding the opposite surface of the white pressure plate opposite to the surface facing the contact glass. An end portion of the white pressure plate is fixed on the upstream side in the document conveying direction with respect to the document reading position in the apparatus main body, and the opposing surface of the white pressure plate faces the document reading position side. An image input device, wherein the image input device is inclined and the other end of the white pressure plate is arranged at a document reading position . Image reading means disposed below the contact glass, conveying means for conveying a document onto the contact glass, and a white pressure plate for pressing the document onto the contact glass, and for determining the white level in the image reading means; In the image input device provided with
Grounding means provided on the apparatus main body and always in contact with the surface of the white pressure plate opposite to the surface facing the contact glass and grounding, the white pressure plate is formed of a flexible member, and the opposite surface of the white pressure plate A flexible conductive plate is attached to the whole, one end of the white pressure plate is fixed on the upstream side in the document conveying direction with respect to the document reading position in the apparatus main body, and the opposing surface of the white pressure plate is inclined toward the document reading position. The other end of the white pressure plate is arranged at a document reading position . 3. The image input device according to claim 2, wherein the white pressure plate is made of a member having a resistance value of 10 ¹³ Ω or more. The image input device according to claim 2, wherein the flexible conductive plate is closely attached to the white pressure plate. 5. The image input device according to claim 4, wherein said flexible conductive plate is made of a leaf spring material having a thickness of 0.01 mm to 0.3 mm. Image reading means disposed below the contact glass, conveying means for conveying a document onto the contact glass, and a white pressure plate for pressing the document onto the contact glass, and for determining the white level in the image reading means; In the image input device provided with
Grounding means provided on the apparatus main body and always in contact with the surface of the white pressure plate opposite to the surface facing the contact glass and grounding, the white pressure plate is formed of a flexible member, and the opposite surface of the white pressure plate A conductive thin film is provided on the whole by any of conductive coating, sputtering, vacuum deposition, or the like, and one end of the white pressure plate is fixed to the document reading position in the apparatus main body on the upstream side in the document conveying direction, and the white pressure plate is fixed. An image input device , wherein an opposite surface of the white pressure plate is inclined toward the document reading position, and the other end of the white pressure plate is disposed at the document reading position .

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