JP2003051917A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader, having simple and inexpensive configuration that eliminates static electricity produced by slide contact of an original, so as to realize superior original carrying and image reading. SOLUTION: A conductive tape 540 is adhered from a slide contact side (upper side) of a skim-through read glass pane 502 over its opposite side (lower side) and a grounded optical frame 551, and the lower side of the skim-through read glass pane 502 clamp the conductive tape 540 to connect the skim-through read glass pane 502 to the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus capable of reading an image while moving a document.

[0002]

2. Description of the Related Art Conventionally, as this type of image reading apparatus,
For example, a flatbed scanner equipped with an automatic document feeder (ADF; automatic document feeder) is known. Further, such an image reading device is used not only in the device itself, but also in an image reading unit such as a copying machine or a facsimile.

In this type of image reading apparatus, a method is used in which an original is brought into close contact with the original glass by an ADF while being conveyed, and an image of the moving original is read from the back side of the original glass.

By the way, in the case of the image reading apparatus in which the original is slid on the original table glass as described above, static electricity is generated between the glass and the original, and the original conveying resistance is increased to cause conveyance failure or accumulation. There is a problem that the generated static electricity is discharged to give an abnormality to the device, and various improvement measures have been proposed and implemented conventionally.

One of the widely used embodiments is the configuration disclosed in Japanese Patent Application Laid-Open No. 1-147443. Here, a conductive layer having a thickness of several tens of μm is formed on the surface of the platen glass, and a conductive thin strip (a thin leaf spring) is brought into contact with the conductive layer so that the conductive layer is electrically connected to the grounded optical frame. It is grounded to.

Further, in Japanese Unexamined Patent Publication No. 9-163041, a conductive film is formed on both sides and side surfaces of the platen glass, and a conductive cushioning material is interposed between the back surface of the glass and the grounded optical frame. Is proposed.

In addition, as shown in FIGS. 9 and 10, a thin leaf spring 581 is attached to a glass surface 582 with a double-sided tape 58.
3, the upper spring portion 581a of the thin leaf spring 581 is elastically contacted with the conductive layer of the glass surface 582, and the thin leaf spring 581 is bent to the back side of the glass to form the lower spring portion 581.
A configuration is known in which b is elastically brought into contact with a grounded optical frame 584.

[0008]

However, in the case of the above prior art, there are the following problems.

According to the proposal of Japanese Patent Laid-Open No. 1-147443, it is necessary to fix a screw when the thin leaf spring is brought into contact with the optical frame, and when the screw foot interferes with the optical system moving inside the optical frame. There is.

Further, in the proposal of Japanese Unexamined Patent Publication No. 9-163041, it is necessary to form a conductive layer on both sides of the glass as well as on both sides thereof, which increases the cost.

Further, in the case of the configuration shown in FIGS. 9 and 10, a gap greater than the thickness of the thin leaf spring 581 (lower spring portion 581b) is required between the optical frame 584 and the glass 582, and the glass 582 is raised. Convex squeezing 584a for
Had to be formed. However, the optical frame 584
It is technically very difficult to form the convex stop 584a in the vicinity of the bend 584b when the glass is bent in the vicinity of the glass contact portion in order to increase the strength.

The present invention has been made in view of the above circumstances, and an object thereof is to remove static electricity generated by sliding contact of a document with a simple and inexpensive structure, and to perform good document transportation and image formation. An object is to provide an image reading device that can realize reading.

[0013]

In order to achieve the above object, in the present invention, a transparent member having a sliding contact surface in close contact with the image surface of a moving original, and an image of the original through the transparent member. In the image reading device including an image reading unit that reads the image, the transparent member has a conductive layer formed on the sliding contact surface side and is fixed from the sliding contact surface to the opposite surface. A conductive member, and is fixed while sandwiching the conductive member between the grounded device body and the opposite surface, and the conductive member is electrically connected to the device body. It is characterized by being

The conductive member may be adhered to the transparent member with a conductive adhesive material.

The conductive member may be a conductive sheet material or a thin metal plate.

The total thickness of the conductive member and the adhesive material is preferably 200 μm or less.

It is preferable that a fixing member for fixing the transparent member to the apparatus main body is provided, and a contact pressure between the conductive member and the apparatus main body is given by the fixing member.

It is preferable that the frame body on the apparatus body side to which the transparent member is fixed is made of a metal material.

A frame body on the apparatus main body side to which the transparent member is fixed may be made of a resin material, and a grounded metal member may be provided at least in a portion of the frame body which is in contact with the conductive member. .

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. These image reading apparatuses are suitable for use as an image reading unit in an image forming apparatus such as a copying machine or a facsimile, in addition to the case where the image reading apparatus is configured as a single apparatus such as a flatbed scanner having an ADF.

Unless otherwise specified, the dimensions, materials, shapes and relative arrangements of the constituent parts described in the following embodiments limit the scope of the present invention thereto. It's not meant.

(First Embodiment) First, an image reading apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic perspective view showing the overall structure of the image reading apparatus of this embodiment, and FIG. 2 is a schematic perspective view showing the attachment structure of the flow reading glass according to this embodiment. FIG. 3 is a schematic diagram showing a cross-sectional structure of the conductive tape according to the present embodiment.

As shown in FIG. 1, the image reading apparatus is roughly composed of an optical frame 551 as a main body of the apparatus, and two platen glass 5 as a transparent member mounted on the upper surface thereof.
01 and the scanning glass 502, and the optical frame 55
And an image sensor 506 as an image reading unit movably provided in the image forming apparatus 1.

When reading a stationary document, the document is placed on the platen glass 501 and the image sensor 506 is moved to scan the image surface of the document. on the other hand,
In the case of flow scanning, the document is moved so as to be in close contact with the upper surface (sliding contact surface) of the flow scanning glass 502, and the image sensor 50 stopped below the flow scanning glass 502.
6, the image surface of the original is scanned through the scanning glass 502.

A conductive layer for conducting static electricity generated by sliding contact with the original is formed on the sliding contact surface of the flow reading glass 502, and a surface treatment for lowering the friction coefficient is further applied thereon. There is.

Further, as shown in FIG. 2, of the sliding contact surface of the flow-reading glass 502, a portion 541 (hatched portion in the figure) which is not subjected to the above-mentioned surface treatment is provided at an end portion outside the document passing range. A conductive tape 540 as a conductive member is attached to this portion.

As shown in FIG. 3, the conductive tape 540 has a conductive sheet 542 made of a conductive sheet material and a conductive adhesive material 543 applied to the back surface of the conductive sheet 542. The reading glass 502 is adhered (fixed) from the sliding contact surface to the opposite surface.

The conductive sheet 542 has a thickness of 35 μm to 5 μm.
Rolled copper foil, electrolytic copper foil, aluminum foil or the like having a thickness of about 0 μm can be used, and when combined with the conductive adhesive material 543, the thickness of the conductive tape 540 itself is about 65 μm to 90 μm.

The flow reading glass 502 is a conductive tape 540.
Approximately 65 μm-9 between the part where the
Although there is a gap difference of about 0 μm, this difference is within the stress limit of the glass and does not pose a structural problem.

In a general image reading apparatus, a flow-reading glass 502 having a length of about 300 mm is used in order to correspond to the length (about 297 mm) in the vertical direction of an A4 size document. In the case of glass, if the float of the edge is about 200 μm, it is within the stress limit, so the thickness of the conductive tape itself is preferably 200 μm or less.
As long as it falls within this range, the conductive member may be a thin metal plate having a slightly larger thickness than the conductive sheet.

As shown in FIG. 2, the conductive tape 540 is
Approximately 10 m on the sliding contact surface side of the back end of the flow reading glass 502
It is attached with a width of m, and the remaining portion is attached to the surface opposite to the sliding contact surface with a width of about 5 mm.
A sheet 544 for aesthetic purposes is attached to the sliding contact surface side from above the conductive tape 540 in order to improve the appearance.

An optical frame (frame body) in which a range of about 4 mm from the edge of the flow reading glass 502 is made of metal sheet metal.
Mounted on 551, the conductive tape 540 contacts the optical frame 551.

Further, the end portion 502a on the far side in the longitudinal direction of the flow reading glass 502 is butted against the abutting portion 551e raised from the optical frame 551, and the glass abutting member 545 is made from the end portion 502b on the front side in the longitudinal direction. Secure with a screw. At this time, the conductive tape 540 attached to the back side has the abutting portion 551 on the optical frame 551.
It is strongly pressed against e and increases conduction performance.

Reference numeral 503 denotes a jump table which supports one side of the long side of the flow reading glass 502, and the jump table 503 has a function of scooping a document passing on the flow reading glass 502.

A claw 503 for urging the flow reading glass 502 from above is provided at an end portion of the jump table 503 outside the original sheet passing area.
a and 503b are provided respectively. Jump stand 5
03 is fixed to the optical frame 551 with screws at the end in the longitudinal direction.

Reference numeral 551f is a part of an optical frame 551 that supports one longitudinal left side of the flow-reading glass 502, and a glass pressing cover 546, which also serves as an exterior, is fixed with screws from above. Glass pressing claws 546a and 546b are provided at both ends of the glass pressing cover 546 outside the document passing range.
In addition to the glass urging claws of the jump table 503 described above, the flow reading glass 502 is urged and fixed to the optical frame 551.

According to the configuration of this embodiment described above,
A conductive tape 540 is attached from the sliding contact surface (upper surface) of the flow reading glass 502 to the opposite surface (lower surface), and the conductive tape 540 is grounded between the grounded optical frame 551 and the lower surface of the flow reading glass 502. By sandwiching the sheet, static electricity generated between the original and the glass surface is eliminated by the conductive tape 540.
It can be led to the back side of the glass via the and effectively escaped to the grounded device body.

By removing the static electricity generated by the sliding contact of the original document in this manner, it is possible to suppress an increase in the original document transportation load due to the static electricity, and it is possible to perform good original document transportation.

Further, in the above-mentioned conventional example (FIGS. 9 and 10), special processing is required for the conductive member and the optical frame. In this respect, however, in this embodiment, the flow-reading glass 502 is used.
Since the conductive tape 540 is directly sandwiched between the optical frame 551 and the optical frame 551, the structure is simplified, and the manufacturing can be facilitated and the cost can be reduced.

Further, since an extremely thin conductive member having a thickness of 200 μm or less is used, even if the conductive member is directly sandwiched between the flow reading glass 502 and the optical frame 551, the influence of stress on the flow reading glass 502 can be ignored. Can be kept within range.

Further, the fixing member of the flow reading glass 502 is fixed to the glass abutting member 545 and the glass pressing claw 503.
a, 503b and 546a, 546b, a plurality of members are used, and by biasing these fixing members, a good contact pressure between the conductive tape 540 and the optical frame 551 is obtained, and the conductivity is improved. To be In the present embodiment, the conduction performance between the surface of the flow reading glass 502 and the optical frame 551 could exhibit 1.5 kΩ or more.

In addition, since the contact pressure is applied by the fixing member for fixing the flow reading glass 502 to the optical frame 551, it is not necessary to separately provide a pressing means for obtaining the contact pressure, and the structure is simple. Can be realized.

Next, with reference to FIGS. 4 and 5, the structure when the image reading apparatus according to the present embodiment is applied to the image reading unit of a copying machine will be described.

FIG. 4 is a schematic structural sectional view of a copying machine equipped with the image reading apparatus according to the present embodiment, and FIG. 5 is a schematic structural sectional view of an image reading section of the copying machine.

As shown in FIG. 4, a copying machine (image forming apparatus) is provided as an image reading apparatus of the present embodiment on the upper part of the apparatus main body 1 including the image forming section 4 and the manual paper feeding section 7. This is a configuration in which the image reading unit 3 is placed.

On the upper part of the image reading section 3, there is placed the original feeding section 2 which is an automatic original feeding device having an original pressing plate 504. The document conveying section 2 is attached via a hinge (not shown) provided behind the image reading section 3. Further, a cassette sheet feeding section 6 having two stages is provided on the lower side of the apparatus main body 1.

As shown in FIGS. 4 and 5, in the image reading section 3, a contact type image sensor 506, a carriage 507, a guide shaft 508, which are image reading means, are provided.
A timing belt 509, a drive pulley 510, and an image processing relay board 511 are provided. Further, it is possible to dispose a document size detection sensor 512 as an option.

The contact image sensor 506 includes a one-dimensional photoelectric conversion element (not shown) and SELFOC lens (trademark).
506a and light sources 506b on both sides of the SELFOC lens (trademark) 506a, and these are arranged in a single housing 506.
It is a device stored in c.

The contact-type image sensor 506 is elastically supported on the carriage 507 by a spring (not shown) and is urged toward the platen glass 501 so that the distance to the document placed on the platen glass 501 does not deviate from the depth of focus. So it keeps a certain distance.

The carriage 507 is a reading drive motor 513.
It is connected to a first timing belt 509 driven by the reciprocating motion in the optical frame 551 along a guide shaft 508 which is perpendicular to the one-dimensional photoelectric conversion element (not shown) in the contact image sensor 506.

The position of the contact image sensor 506 is controlled by the rotation frequency and rotation time of the motor with the detection timing of the home position sensor 514 as a base point.

The document conveying section 2 is roughly composed of a document placing table 21 on which a document is placed, a separating roller 22b for separating and feeding the document D from the document placing table 21, and a flow reading glass of the image reading section 3 for the document D. A document transport roller 22 that transports onto the 502
It is configured to include a conveying unit such as c and a document discharge tray 23 from which a document D whose image has been read is discharged.

The original document table 21 is provided with a slider 21a which is slidable in a direction (widthwise direction of the original document D) orthogonal to the conveying direction of the original document D, and the slider 21a is used to load the original document table 21. Both sides of the document D can be aligned.

The operation when the image of the original is read in the copying machine having the above-mentioned structure will be described with reference to FIGS. 6 and 7.

FIG. 6 is a schematic perspective view showing the external appearance of the copying machine, and FIG. 7 is a schematic configuration diagram of the control circuit of the copying machine.
The control described below is performed by the main body control unit 51 shown in FIG.
Is performed by.

(Still Original Reading Operation) The still original reading (still reading) is performed as follows.

When the document D is placed on the platen glass 501 and the document feeding section 2 having the document pressure plate 504 is closed, the size of the document is detected by the document size detection sensor 512 at a predetermined opening / closing angle. It

When the copy start key 601a is pressed, a recording paper of a predetermined size is selected according to the detected document size and the information of the scaling ratio input from the operation unit 5, and the sheet material S is fed. Be started. If there is no recording sheet of an appropriate size, the fact is displayed on the display unit 602.

After pressing the start key 601a, shading is performed, scanning is performed from the front end of the original, and A / D conversion is performed by the image processing relay board 511 provided in the image reading section 3,
It is sent to the image processing unit 52 of the apparatus body. The contact image sensor 506 and the image processing relay board 511 are electrically connected by a flat cable (not shown).

When the scanning is completed, the reading drive motor 513 rotates in the reverse direction to return the contact image sensor 506 to the original standby position.

(Operation of Reading Moving Document) Reading (moving reading) of a moving document is performed as follows.

When the document D is placed on the document table 21,
The document detection sensor 21b detects the presence of a document. Next, the size of the document is detected by the length detection sensor 21c and the width detection sensor 21d that detects the width from the movement amount of the slider 21a, the information is passed to the main body control unit 51 in the apparatus main body 1, and the operation unit is operated. A recording paper of a predetermined size is selected according to the scaling ratio input from 5. If there is no recording sheet of an appropriate size, the fact is displayed on the display unit 602.

When the document detecting sensor 21b does not detect the document, the platen glass 501 on the stationary reading side is used.
When it is determined that the original is placed on the original, the contact image sensor 506 scans the original table glass 501 side.

When the start key 601a on the operation unit 5 is pressed, the contact type image sensor 506 performs shading, and the document table glass 50 is sandwiched by the jump table 503.
It moves to the lower side of the flow reading glass 502 on the side opposite to 1, and stands still.

A plurality of documents D stacked on the document table 21 are separated by a separation roller 22b which is in pressure contact with the separation pad 22a.
The sheets are separated one by one, and are conveyed to the U-turn sheet passing path 22d by the document conveying roller 22c.

Further, the document D is a document leading edge detection sensor 22f.
After passing through the sheet feeding roller 22e, the image reading position 51
5, the original image starts to be scanned at the timing when the leading edge of the original reaches the image reading position where the contact-type image sensor 506 is stopped, and the image signal is transferred to the A / A relay substrate 511.
The D conversion is performed and the image is transmitted to the image processing unit 52 of the apparatus body 1.

At the image reading position 515, the image surface of the document D is scanned by the document pressing roller 22g.
The contact type image sensor 506 is in close contact with the upper surface (sliding contact surface) of No. 2 and reads the image of the document D through the flow reading glass 502.

The document D from which the image has been read is scooped up from the upper surface of the scanning glass 502 by the jump table 503,
The document is discharged onto the document discharge tray 23 via the document discharge rollers 22h.

Static electricity is generated when a document passes on the flow-reading glass 502, but as described above, the charge is transferred from the conductive layer on the surface of the flow-reading glass 502 to the conductive tape 54.
It passes through 0 and falls to the frame ground.

By removing the static electricity generated by the sliding contact of the original document in this way, it is possible to suppress the increase of the original document transportation load due to the static electricity, and it is possible to perform the excellent original document transportation. Further, since it is possible to prevent the malfunction of the apparatus and the noise due to the discharge of the static electricity accumulated on the flow reading glass 502, it is possible to read and form an excellent image.

When all the originals placed on the original table 21 have been read and the original detection sensor 21b detects "no original", the contact image sensor 506 returns to the original standby position.

(Second Embodiment) FIG. 8 shows a second embodiment of the present invention. Although the optical frame is made of a metal material in the first embodiment, the optical frame is made of a resin material in the present embodiment.

Since other structures and operations are the same as those of the first embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

As shown in the figure, in this embodiment, the optical frame 591 on the apparatus main body side to which the flow reading glass 502 is fixed is made of a resin material. A ground plate 592 is provided on a portion of the optical frame 591 that supports the flow-reading glass 502, that is, a portion that contacts the conductive tape 540 attached to the lower surface of the flow-reading glass 502. The ground plate 592 is grounded to the frame ground of the power supply unit 593 of the apparatus body.

With this structure, even if the optical frame 591 is made of a resin material, the flow-reading glass 50 is stably supplied.
The charge accumulation on the surface of No. 2 can be suppressed, and the same effect as that of the first embodiment can be obtained.

[0077]

As described above, according to the present invention,
With a simple and inexpensive structure, it is possible to eliminate static electricity generated by sliding contact of a document and realize good document transportation and image reading.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an overall configuration of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a mounting structure of the flow-reading glass according to the embodiment.

FIG. 3 is a schematic view showing a cross-sectional structure of a conductive tape according to the same embodiment.

FIG. 4 is a schematic cross-sectional configuration diagram of a copying machine including the image reading apparatus according to the embodiment.

FIG. 5 is a schematic cross-sectional view of an image reading unit (image reading device) of the copying machine.

FIG. 6 is a schematic perspective view showing an appearance of the copying machine.

FIG. 7 is a schematic configuration diagram of a control circuit of the copying machine.

FIG. 8 is a schematic perspective view showing a mounting structure of a flow reading glass according to a second embodiment of the present invention.

FIG. 9 is a schematic perspective view showing a mounting structure of a flow-reading glass according to a conventional technique.

FIG. 10 is a schematic perspective view showing a mounting structure for a flow-reading glass according to a conventional technique.

[Explanation of symbols]

1 Image forming device body 2 Document feeder 3 Image reading unit (image reading device) 4 Image forming section 5 Operation part 6 cassette paper feeder 7 Manual feed section 21 Document Plate 21a slider 21b Document detection sensor 21c Length detection sensor 21d width detection sensor 22a Separation pad 22b Separation roller 22c Document transport roller 22d U-turn paper pass 22e Paper feed roller 22f Document edge detection sensor 22g Document holding roller 22h Document ejection roller 23 Original output tray 51 body control unit 52 Image processing unit 501 platen glass 502 Flowing reading glass 502a, 502b Edges of non-scanning glass 503 jump stand 503a, 503b Glass holding claw 504 Original pressure plate 506 Contact image sensor 506a Selfoc lens 506b Light source 506c housing 507 carriage 508 guide shaft 509 Timing Belt 510 drive pulley 511 Image processing relay board 512 Document size detection sensor 513 Read drive motor 514 Home Position Sensor 515 image reading position 540 conductive tape 542 conductive sheet 543 conductive adhesive 544 sheets 545 Glass butting member 546 glass holder cover 546a, 546b Glass holding claw 551 optical frame 551e Abutting part 591 optical frame 592 ground plate 593 power supply unit 601a Start key 602 display D manuscript

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 1/00 108 H04N 1/12 Z 5C072 F term (reference) 2H072 CA05 JA03 JC09 2H076 BA24 BA47 BA95 BA99 3F101 AA07 AA13 LA02 LB02 5B047 AA01 BA01 BB02 BC18 BC20 BC30 5C062 AA02 AA05 AB02 AB32 AD06 BA01 5C072 AA01 BA02 DA25 EA07 LA02 NA10 XA01

Claims (7)

[Claims] 1. An image reading apparatus comprising: a transparent member having a sliding contact surface that comes into close contact with an image surface of a moving original document; and image reading means for reading the image of the original document through the transparent member. Has a conductive layer formed on the sliding contact surface side and has a conductive member fixed from the sliding contact surface to the opposite surface, and is opposite to the grounded device body. The image reading device is characterized in that it is fixed while sandwiching the conductive member between the side surface and the side surface, and the conductive member is electrically connected to the device main body. 2. The image reading apparatus according to claim 1, wherein the conductive member is adhered to the transparent member with a conductive adhesive material. 3. The image reading apparatus according to claim 2, wherein the conductive member is a conductive sheet material or a thin metal plate. 4. The combined thickness of the conductive member and the adhesive material is 200 μm or less.
The image reading apparatus described in 1. 5. A fixing member for fixing the transparent member to an apparatus main body, wherein contact pressure between the conductive member and the apparatus main body is given by the fixing member. The image reading apparatus according to any one of the above. 6. A frame body on the apparatus main body side, to which the transparent member is fixed, is made of a metal material.
The image reading apparatus according to any one of the above. 7. A frame body on the apparatus main body side, to which the transparent member is fixed, is made of a resin material, and a grounded metal member is provided in at least a portion of the frame body that is in contact with the conductive member. Any one of claims 1 to 5 characterized in that
The image reading device described in the paragraph.