JP2010042894A - Document conveying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document conveying apparatus capable of avoiding occurrence of any defect caused by the contact of a contact glass with an endless belt, and executing the operation for attracting paper dust or the like while ensuring the consistent document conveying performance. <P>SOLUTION: A document conveying means comprises: a conveying belt 100 for attracting a document to be fed and conveying it; two or more belt conveyance rollers (a driving conveyance roller 103, and a driven conveyance roller 104); and an AC power source 102 for forming the electrostatic attracting force by applying the alternating voltage to the conveying belt 100. At least one of the two or more belt conveyance rollers of the document conveying means is attached/detached to/from a contact glass 24 surface. The document is conveyed with the belt conveying roller being separated from the contact glass 24 surface at the reading position with a small space therebetween. Besides, the belt conveying roller is brought into contact with the contact glass 24 in a non-driven condition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an original conveying apparatus that is used in a copying machine, a scanner, a facsimile machine, and the like and conveys an original to a reading position.

  Conventionally, various image reading apparatuses capable of reading both book originals and sheet-through originals have been developed. The apparatus includes a reading unit configured to move when reading a document stationary on a contact glass and stop on the slit glass when reading a conveyed document, and a document at a predetermined reading position. And an automatic document conveying device that can discharge a document after reading and a technology provided with the document are disclosed (for example, see Patent Document 1).

  However, in this case, since a slit glass for reading a sheet-through original is required in addition to the contact glass, the apparatus is increased in size and cost accordingly. On the other hand, a document in which a book document and a sheet-through document are read with one contact glass is disclosed (for example, see Patent Document 2).

  However, in the image reading apparatus having such a conventional automatic document conveying device, the document after being read at the end portion of the contact glass is carried out from the end portion of the contact glass by the conveying roller, and the side of the main body of the device is scanned. Because the paper is discharged onto the paper discharge tray, there must be an area where a paper discharge tray is provided on the side of the main body, and a mechanism for scooping up the original is placed on the paper discharge tray on the side of the main body. As a result, the automatic document feeder becomes longer in the longitudinal direction, and there is a problem that the installation space for the image reading apparatus increases.

  Therefore, as in Patent Documents 3 and 4, a reading optical system that moves when reading a stationary document on the contact glass and stops at the end of the contact glass when scanning a conveyed document. When reading a sheet-through document, the document placed on the document table is conveyed toward the end of the contact glass, and the document after being read at the end of the contact glass is transferred to the end of the contact glass. Then, it is carried out by a conveying roller and discharged onto a discharge tray on the side of the apparatus main body. In this case, the apparatus can be reduced in size and cost as much as the book document and the sheet-through document can be read with one contact glass. Further, by forming uneven electrolysis on the conveyor belt, the document is electrostatically adsorbed, scooped up on a presser cover above the contact glass, and discharged.

Japanese Patent Laid-Open No. 2-48679 Japanese Patent Laid-Open No. 2-77075 JP 2003-206045 A JP-A-8-254765

  However, in the conventional techniques as described above, paper dust and other dust generated from an original during conveyance of the original cannot be effectively removed from the contact glass without damaging the glass surface. There was a problem.

  The present invention has been made in view of the above, and avoids the generation of scratches due to contact between the contact glass and the endless belt, and ensures stable document conveyance performance, while adsorbing paper dust and the like. The purpose is to enable operation.

  In order to solve the above-described problems and achieve the object, the invention according to claim 1 is provided with an original conveying means that is mounted on an image reading apparatus and conveys an original to a reading position on a contact glass surface of the image reading apparatus. The document conveying device for discharging the document after reading the document, wherein the document conveying means winds the endless belt for attracting and conveying the fed document and winding the endless belt. Applying an alternating voltage to the endless belt and at least two or more belt conveying rollers that stretch, drive the endless belt to rotate, and move the endless belt with respect to the contact glass surface at a predetermined timing; An application member that forms an electrostatic attraction force, and at least one of the two or more belt conveyance rollers of the document conveyance means is configured to be able to contact and separate from the contact glass surface. During document reading, to convey the original separated by a small gap at the reading position of the contact glass surface, while in a state not rotated, characterized by contacting the contact glass.

  The invention according to claim 2 further includes document presence / absence detection means for detecting presence / absence of document placement according to claim 1, and the document transport means includes information detected by the document presence / absence detection means. Accordingly, the contact glass surface is contacted and separated.

  According to a third aspect of the present invention, in the second aspect of the present invention, the document conveying means starts to rotate according to the information detected by the document presence / absence detecting means, and simultaneously applies the application member to the endlessly. The surface on which the uneven electrolysis is formed on the belt-like belt continues to rotate at least to a position reaching the vertically upper side of the contact glass, and after stopping, moves to a position in contact with the contact glass.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the document further includes a document presence / absence detection unit that detects whether or not a document is placed, and a document discharge detection unit that detects discharge of the document. The document conveying means contacts and separates from the contact glass surface in accordance with detection information from the document presence / absence detection means and the document discharge detection means.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the document further includes a document presence / absence detection unit that detects whether or not a document is placed, and a document discharge detection unit that detects discharge of the document. The roller that stretches the endless belt of the document conveying means stops rotating according to the detection information of the document presence / absence detecting means and the document discharge detecting means, and moves to a position where it contacts the contact glass. It is characterized by.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the roller that stretches the endless belt of the document conveying means is a position where a minute gap is provided again with respect to the contact glass after contacting the contact glass. And the rotational driving is started.

  According to a seventh aspect of the present invention, in the first aspect of the present invention, a third roller is provided above and downstream of a pair of rollers that stretch the endless belt of the document conveying means, and the endless The belt is stretched by three rollers.

  According to an eighth aspect of the present invention, in the seventh aspect of the present invention, the non-uniform electrolysis formed on the endless belt is neutralized at a position in contact with the top of the third roller in the horizontal direction, and the endless belt is removed. An adhering matter removing means for removing adhering matter on the upper side, and an adhering matter collecting member that is provided vertically below the adhering matter removing means and collects the adhering matter that is removed by the extraneous matter removing means. Features.

  According to a ninth aspect of the present invention, in the eighth aspect of the present invention, the deposit collection member is provided with a full detection means for detecting that the collected amount of the deposit is substantially full.

  The invention according to claim 10 is characterized in that, in the description of claim 8 or 9, the deposit recovery member is removable from the apparatus main body.

  In the document conveying device according to the present invention, the document conveying means sucks and conveys the fed document, and winds and stretches the endless belt, and the endless belt is driven to rotate. And at least two belt conveying rollers that move relative to the contact glass surface at a predetermined timing, and an application member that applies an alternating voltage to the endless belt to form an electrostatic attraction force. In addition, at least one of the two or more belt conveying rollers of the document conveying means is configured to be able to contact and separate from the contact glass surface, and when reading the document, the reading position on the contact glass surface is separated by a minute gap. By contacting the contact glass while the document is being transported and not being driven to rotate, scratches caused by the contact between the contact glass and the endless belt can occur during document transport. To avoid the occurrence, while ensuring a stable document conveying performance, an effect that the operation for the adsorption of the paper powder or the like becomes possible.

  Exemplary embodiments of a document conveying device according to the present invention will be explained below in detail with reference to the accompanying drawings.

(Embodiment)
FIG. 1 is an explanatory diagram showing the overall configuration of the automatic document feeder according to this embodiment. FIG. 2 is an explanatory diagram showing the configuration of the automatic document feeder according to this embodiment and the operating state at the time of reading. FIG. 3 shows the configuration of the automatic document feeder according to this embodiment and the non-reading state. It is explanatory drawing which shows the operation state at the time.

  In FIG. 1, reference numeral 21 denotes a scanner device that optically reads a document on a contact glass 24 and obtains image information as an electrical signal. A plurality of documents are placed on the scanner device 21 one by one on the contact glass 24. An automatic document feeder 22 for carrying the document to the reading position is placed. The automatic document feeder 22 is configured to invert a document placed on a document tray 23 serving as a document placement table in the direction of arrow R and convey it to a reading position on the contact glass 24.

  The scanner device 21 is rotatably attached to the main body 21 a of the scanner device 21 by a support member 25, and can be opened and closed with respect to the contact glass 24. Further, the scanner device 21 is provided with a traveling body 26 that can move in the horizontal direction in the drawing and scan the document surface. The traveling body 26 has a light source 27 such as a lamp that irradiates light on the document surface and a light source 27. The mirror 28 is configured to reflect the light emitted from the document surface to the document surface. The light reflected by the mirror 28 is imaged on the lens 32 by the mirrors 29 and 30 of the mirror unit 31, and then image information is read by the photoelectric conversion element 33. The traveling body 26, mirror unit 31, lens 32, and photoelectric conversion element 33 constitute a reading optical system. In addition, a scale 34 is provided at the end of the contact glass 24, and when the book original is read on the contact glass 24, the end of the book original is abutted against the scale 34. Thus, the traveling body 26 is caused to travel from the reading position B to the left side.

  On the other hand, the automatic document feeder 22 feeds and feeds the document 1 placed on the document tray 23 onto the traveling body 26 stopped below the reading position A as shown in FIG. 106, a paper feed unit composed of a paper feed driven roller 107, a paper feed belt 108, and a separation roller 109, a transport belt 100 stretched between the transport drive roller 103 and the transport driven rollers 104, 114, and a transport guide 105 With units. The document conveyed and read by the conveying means is discharged onto the discharge tray 40 by a discharge unit including an upper discharge guide 110, a lower discharge guide 111, a discharge driving roller 112, and a discharge driven roller 113.

  A reference numeral 120 shown in FIG. 2 includes a microcomputer system including a CPU, a RAM, a ROM, and the like, and a control unit that controls the scanner device 21 and the automatic document feeder 22 as a whole. Reference numeral 121 is described later. A contact / separation drive unit for contacting / separating the conveyance drive roller 103 wound around the endless belt conveyance belt 100 with respect to the surface of the contact glass 24. Reference numeral 122 denotes an operation setting of the scanner device 21 and the automatic document conveyance device 22. This is a display unit that has setting keys and numeric keys for performing operations, and displays the status of the apparatus on the liquid crystal panel. As specific means of the contact / separation driving unit 121, a known mechanism such as a mechanism for contacting / separating the transport driving roller 103 by ON / OFF by a solenoid, a cam mechanism, or the like is used. The controller 120 receives a document presence / absence signal from the document stack detection sensor 117, a document discharge signal from the discharge detection sensor 118, a paper dust full signal from the paper dust detection sensor 116, and the like.

The conveyor belt 100 is an endless belt and is composed of a double-structured resin film. The resin film is composed of a high-resistance (10 ¹⁴ Ω or more) film on the surface layer and a low-resistance layer on the back surface layer. (10 ⁸ Ω or less) It is composed of a film. The endless transport belt 100 is wound around a transport drive roller 103 and transport driven rollers 104 and 114, and is rotated in the clockwise direction in the drawing by the rollers 103, 104, and 114.

The conveyance drive roller 103 is grounded, and the electrode roller 101 is in sliding contact with the conveyance drive roller 103 via the conveyance belt 100. The electrode roller 101 is composed of a metal roller or a metal roller coated with 10 ⁸ to 10 ¹¹ Ω rubber, and an AC voltage is applied to the electrode roller 101 from an AC power source 102. ing.

  Accordingly, the transport belt 100 is moved in the clockwise direction by the transport driving roller 103 at a constant speed of vmm / s, and the paper feed position of the document 1 is in contact with the moving direction of the endless transport belt 100. This is a range in contact with the electrode roller 101 as the counter electrode on the downstream side of the contact position. For this reason, an AC voltage is applied to the surface of the conveyor belt 100 via the electrode roller 101 by the AC power source 102 before the document 1 is fed to the surface thereof. , −σ are alternately arranged at a pitch of v / Amm, and an electric field density pattern is formed. A similar charge density pattern is also formed on the back surface of the conveyor belt 100 with a 180 ° shift. An unequal electric field is formed in the vicinity of the surface of the conveyor belt 100 by the charge density pattern thus formed. The electrode roller 101 and the AC power source 102 described above constitute an application member.

  The document 1 adsorbed on the surface of the conveyance belt 100 by the non-uniform electrolysis is peeled off from the conveyance belt 100 because the diameter of the conveyance drive roller 103 is set so that the stiffness of the document <the electrostatic adsorption force. It is conveyed to the reading position A without doing. As a result, at the reading position A, the conveying belt 100 is disposed at a position about 0.1 to 0.5 mm away from the contact glass 24. Therefore, the conveying belt 100 is adsorbed and conveyed by the uneven electrolysis. The document to be printed is conveyed without contacting the contact glass 24. After passing through the reading position A, the transport driven roller 104 is positioned above the transport driving roller 103, so that the document 1 is gradually fed upward while being attracted to the transport belt 100, and the leading edge of the document 1. Reaches the conveying driven roller 104, the diameter of the conveying driven roller 104 is set to a size such that the stiffness of the original is greater than the electrostatic attraction force, so that it peels from the conveying belt 100 at a position that has passed through the conveying driven roller 104. Then, it is guided into the paper discharge upper guide 110 and the paper discharge lower guide 111. A paper discharge driving roller 112 and a paper discharge driven roller 113 are provided in the vicinity of the paper discharge port, and the original 1 is discharged onto the paper discharge tray 40 by this roller pair.

  In the present embodiment, the document 1 delivered from the paper feed unit to the transport unit is transported while being electrostatically attracted to the transport belt 100 in the entire transport path, so that the document 1 is stable in the transport path. Thus, there is no skew (slanting feed), slip, and the like due to component variations of the conveying roller pair as in the prior art. Further, even at the reading position A, the document 1 is in a state where it is adsorbed to the entire surface of the conveyance belt 100. Therefore, when the trailing edge of the document passes through the conventional conveyance roller or due to the effect of the clearance of the transfer section on the conveyance path. Occurrence of shock jitter (a phenomenon in which a read image flies due to a minute conveyance deviation) is also avoided, and stable reading is possible.

  When the document 1 is set on the document tray 23, the document stack detection sensor 117 detects the setting of the document 1. Based on this detection information, the conveyance drive roller 103 is driven to rotate at the reading position 103a, and at the same time, uneven electrolysis is formed on the conveyance belt 100 from the AC power supply 102 via the electrode roller 101. The conveyance roller 103 stops rotating after continuing to rotate until the uneven electrolysis formed on the conveyance belt reaches the reading position A. At this time, the conveyance driving roller 103 is moved to the position 103b shown in FIG. 3 by the contact / separation driving unit 121, and the conveyance belt 100 and the contact glass 24 come into contact with each other at the position shown in B. At the position B, non-uniform electrolysis is formed on the conveyor belt 100, so that paper dust, dust, etc. on the contact glass 24 are adsorbed.

  Thereafter, the transport driving roller 103 returns to the position 103a in FIG. 2 and starts to rotate again. A neutralization brush 119 is provided in the vicinity of the conveyance driven roller 114 on the downstream side in the conveyance direction, and the static electricity on the conveyance belt 100 is neutralized by the neutralization brush 119, and simultaneously adsorbed paper dust, dust, etc. Is also scraped off and accumulates in the paper dust receiving portion 115. Further, when all the documents 1 on the document tray 23 are conveyed and the document stacking detection sensor 117 detects that there is no document, and when the discharge detection sensor 118 detects the completion of the discharge, the conveyance drive roller 103 is stopped. Movement to the position 103b and adsorption of paper dust, dust, etc. at the position B are performed, and paper dust, dust, etc. accumulate on the paper dust receiving portion 115 as described above. The paper dust receiving unit 115 is configured to be removable from the automatic document feeder 22. When the paper dust detection sensor 116 detects the accumulation of paper dust inside the paper dust receiving unit 115, for example, the operation / display unit 122 displays an indication that the paper dust receiving unit 115 is substantially full or a display prompting disposal. By doing so, it is possible to take out the paper dust receiving portion 115 and discard the accumulated paper dust, dust and the like.

  When reading a book document or the like, the automatic document feeder 22 is opened, and the end of the document is placed on the contact glass 24 against the scale 34. The traveling body 26 travels to the left from the reading position B in FIG. 1 by a start switch or the like (not shown), irradiates the original surface from the light source 27, and the reflected light is reflected by the mirrors 28 to 30 and imaged on the lens 32. After that, image information is read by the photoelectric conversion element 33.

  Therefore, according to the embodiment described above, at least one of the two rollers that stretch the conveyor belt 100 can be moved, that is, the conveyor belt 100 is wound in this embodiment. The conveyance driving roller 103 is configured to be separated / contacted with the contact glass 24 surface, and is in contact with the contact glass 24 surface only when stopped, so that the contact glass 200 and the conveyance belt 100 are in contact with each other during document conveyance. It is possible to perform the operation for adsorbing paper dust and the like while preventing the generation of scratches and ensuring stable document conveyance performance.

  Further, a movable roller (in this example, the conveyance driving roller 103) conveys the document by rotating at a position where a minute gap is provided with respect to the contact glass 24. In order to move to the contact position, paper dust and other dust loaded on the contact glass 24 are attracted to the transport belt 100. Thereby, the conveyance driving roller 103 conveys the document by rotating at a position where a minute gap is provided with respect to the contact glass 24, and moves to a position where it comes into contact with the contact glass 24 while being stopped when adsorbing paper dust or the like. Therefore, it is possible to avoid generation of scratches due to rubbing with the contact glass 24 during conveyance, and to reliably adsorb paper dust, other dust, etc. to the conveyance belt 100.

  Further, a movable roller (in this example, the conveyance driving roller 103 is moved on the basis of detection information provided by a means (document stacking detection sensor 117) provided on the document tray 23 for detecting the presence or absence of a document. The paper dust, dust, etc. on the contact glass 24 are adsorbed to the belt before conveyance based on the detection information on the presence or absence of the original by the original set, so that paper dust removal scanning is performed when the original is set. The top 24 paper dust, dust and the like can be removed, and the quality of the read image can be improved.

  In addition, the conveyance roller 100 that stretches the endless belt starts to be rotated and is simultaneously applied by the application member based on detection information from the document presence / absence detection means (document stacking detection sensor 117) provided on the document tray 23. The transport roller 100 continues to rotate until the surface on which the uneven electrolysis is formed on the endless belt reaches at least a position above the contact glass 24, and after the stop, the movable roller is the contact glass 24. By moving to a position in contact with the contact glass 24, the surface to which uneven electrolysis is applied is reliably brought into contact with the reading position of the contact glass 24. Thus, after the document set is detected, the movable roller starts to rotate and is applied to the belt 100 for simultaneous conveyance to bring the surface on which uneven electrolysis is formed into contact with the contact glass 24. The upper paper dust, dust, etc. can be reliably removed.

  The movable roller includes means for detecting the presence or absence of a document (document stacking detection sensor 117) provided on the document tray 23, and means for detecting discharge of the document by the sheet discharge means (discharge detection sensor 118). ), The paper dust, dust, etc. on the contact glass 24 are adsorbed to the belt after the reading of all the set originals is completed. As a result, paper dust, dust and the like on the contact glass 24 are removed even after the reading of the document is completed, so that paper dust generated during conveyance can be removed immediately, and sticking due to accumulation of paper dust or the like can be avoided.

  Further, based on detection information from the document tray 23 and the document stacking detection sensor 117 of the paper discharge unit, the conveyance roller 100 that stretches the endless belt stops rotating and the movable roller is in contact with the contact glass 24. By moving to, the contact glass 24 is brought into contact with the endless belt in a short time after the reading is completed with the non-uniform electrolysis applied to the endless belt. As a result, paper dust and the like are removed immediately after the document is discharged, so that time efficiency can be improved.

  In addition, the movable roller moves to a position where a minute gap is provided again with respect to the contact glass 24 after contacting the contact glass 24, and the conveying roller 100 that stretches the endless belt starts to rotate. The conveyor belt 100 is driven to rotate while adhering paper dust and other dust on the contact glass 24. As a result, after adsorbing the paper dust, dust, etc., the transport roller 100 is separated from the contact glass 24 and starts rotating, so that the paper dust, dust, etc. accumulated at the reading position can be moved (transported). Become.

  Further, a third roller (conveyance driven roller 114) is provided on the upper downstream side of the pair of rollers that stretch the endless belt, and the endless belt is stretched by three rollers, so that it is attracted to the conveyance belt 100. A means to peel off the paper dust and other garbage from the belt is provided. As a result, by neutralizing the belt with three rollers, it is possible to dispose a static elimination brush and paper dust receptacle, and it is possible to collect paper dust, dust, and the like accumulated on the contact glass 24. .

  In addition, a means (static charge brush 119) for removing uneven electrolysis formed on the endless belt is provided at a position in contact with the horizontal vertex of the third roller, and a box-shaped member (paper powder receiving portion) is vertically below 115), and the paper dust adsorbed on the conveyor belt 100 and other dusts are scraped off with a static elimination brush and stored in the paper dust tray. As a result, the neutralizing brush 119 is disposed at a position in contact with the horizontal apex of the third roller, and the paper dust catch is provided immediately below, so that the paper dust, dust, etc. sucked and conveyed from the contact glass 24 can be removed. It can be stored in one place, and scattering inside the apparatus can be prevented.

  Further, a detection means (paper dust detection sensor 116) is provided inside the box-shaped member (paper dust receiving portion 115) to detect paper dust, dust, etc. accumulated in the paper dust receptacle. Thereby, the amount of accumulation can be detected by the paper dust detection sensor 116 inside the paper dust receiving portion 115, and the accumulated paper dust, dust, etc. can be prevented from overflowing and scattering.

  In addition, the box-shaped member (paper dust receiving portion 115) is configured to be removable from the main body of the apparatus, so that the paper dust detection sensor 116 inside the paper dust receptacle detects accumulation of accumulated paper dust and other dust. Then remove from the body and discard the deposit. As a result, the paper dust tray can be removed from the main body of the apparatus. After confirming the detection information by the paper dust detection sensor 116, the accumulated paper powder, dust, etc. can be taken out from the apparatus and discarded, and reused. Can do.

  As described above, the document conveying device according to the present invention is useful for a scanner, a copying machine, a facsimile machine, and the like. In particular, a document for removing paper dust generated on the contact glass surface due to the conveyance of the document and other dust is removed. Suitable for all conveying devices.

It is explanatory drawing which shows the whole structure of the automatic document feeder concerning this Embodiment. FIG. 2 is an explanatory diagram showing a configuration of an automatic document feeder according to this embodiment and an operation state at the time of reading. It is explanatory drawing which shows the structure of the automatic document feeder concerning this embodiment, and the operation state at the time of non-reading.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Scanner apparatus 22 Automatic document conveying apparatus 23 Document tray 24 Contact glass 100 Conveying belt 101 Electrode roller 102 AC power supply 103 Conveyance drive roller 104,114 Conveyance driven roller 115 Paper dust receiving part 116 Paper dust detection sensor 117 Document stacking detection sensor 118 Ejection Detection sensor 119 Static elimination brush 120 Control unit 121 Contact / separation drive unit 122 Operation / display unit

Claims (10)

An original conveying device that is mounted on an image reading apparatus and includes an original conveying means for conveying an original to a reading position on a contact glass surface of the image reading apparatus, and discharges the original after reading the original,
The document conveying means includes:
An endless belt for sucking and transporting a fed document;
Winding and stretching the endless belt, rotationally driving the endless belt, and moving the endless belt with respect to the contact glass surface at a predetermined timing; and
Applying an alternating voltage to the endless belt to form an electrostatic attraction force; and
Have
At least one of the two or more belt conveying rollers of the document conveying means is configured to be able to contact and separate from the contact glass surface,
An original conveying apparatus that, when reading an original, conveys the original at a reading position on the surface of the contact glass with a small gap, and contacts the contact glass in a state where the original is not rotated. Furthermore, it has a document presence / absence detection means for detecting the presence / absence of document placement,
The document conveying device according to claim 1, wherein the document conveying unit contacts and separates from the contact glass surface according to detection information by the document presence / absence detecting unit.   The document conveying means starts to rotate according to the detection information from the document presence / absence detection means, and simultaneously applies the application member, and the surface on which the uneven electrolysis is formed on the endless belt is at least the 3. The document conveying device according to claim 2, wherein the rotation of the contact glass is continued until it reaches a position vertically above the contact glass, and after stopping, the apparatus moves to a position where the contact glass contacts the contact glass. Furthermore, it has a document presence / absence detection means for detecting whether or not a document is placed, and a document discharge detection means for detecting the discharge of the document.
2. The document conveying apparatus according to claim 1, wherein the document conveying unit contacts and separates from the contact glass surface in accordance with detection information of the document presence / absence detecting unit and the document discharge detecting unit. Furthermore, it has a document presence / absence detection means for detecting whether or not a document is placed, and a document discharge detection means for detecting the discharge of the document.
The roller that stretches the endless belt of the document conveying means stops rotating according to the detection information of the document presence / absence detecting means and the document discharge detecting means, and moves to a position that contacts the contact glass. 2. The document conveying device according to claim 1, wherein   2. The roller that stretches the endless belt of the document conveying means moves to a position where a minute gap is provided with respect to the contact glass again after contacting the contact glass, and starts to rotate. Document transport apparatus described in 1.   7. The apparatus according to claim 1, wherein a third roller is provided above and downstream of a pair of rollers for stretching the endless belt of the document conveying means, and the endless belt is stretched by three rollers. The document feeder according to any one of the above. An adhering matter removing means for removing the non-uniform electrolysis formed on the endless belt and removing the adhering matter on the endless belt at a position in contact with the horizontal vertex of the third roller;
An adhering matter collecting member that is provided vertically below the adhering matter removing means and collects the adhering matter removed by the adhering matter removing means;
The document conveying device according to claim 7, further comprising:   9. The document conveying apparatus according to claim 8, wherein the adhering matter collecting member is provided with a full detecting means for detecting that the collected amount of adhering matter is substantially full.   10. The document conveying apparatus according to claim 8, wherein the deposit collecting member is configured to be removable from the apparatus main body.

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