JP2001233509A - Image reading device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device capable of stably and smoothly feeding a document. SOLUTION: A pressing plate 102 for pressing a document 100 against a transfer belt 86 is disposed on a sheet feed guide plate 93 on a downstream side in the arrow C. The pressing plate 102 has generally the same width as that (length in the direction perpendicular to the direction of the arrow C) of the sheet feed guide plate 93. The pressing plate 102 is continued to the sheet feed guide plate 93 at the downstream side end part in the direction of the arrow C, and extends from the downstream side end part to near a transfer roller nearest the sheet feed rollers 94 and 96 of a plurality of transfer rollers 92.

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 for reading an image recorded on a document and an image forming apparatus provided with the image reading apparatus.

[0002]

2. Description of the Related Art As an output device of a computer or a work station, an ink jet type image forming apparatus for forming an image on a recording medium by discharging ink, or an electrophotographic type forming apparatus for forming an image on a recording medium using a developer or the like. Image forming apparatuses are known. Some of these image forming apparatuses include an image reading device that reads an image recorded on a document.

The image reading apparatus has a platen glass on which a document is placed or passed with its image side down. A document feeder (document feeder, DF) that automatically conveys the original so that the original passes while contacting the original glass is arranged on the original glass. An endless conveyance belt is incorporated in the document conveyance device, and the conveyance belt is in contact with the document table glass. A document is inserted between the transport belt and the platen glass, and the transport belt is rotated. As a result, the original is transported in a predetermined transport direction while contacting the original platen glass.

The document feeder has a document insertion opening through which a document is inserted between the transfer belt and the platen glass. In the vicinity of the document insertion slot, a pair of transport rollers for transporting the document toward the platen glass while nipping the document are arranged. The document passes through the document insertion slot by the pair of transport rollers, is inserted between the document table glass and the transport belt, passes through the document table glass while being in contact with the upper surface of the document table glass by the transport belt, and discharges the document. It is discharged from the exit. The platen glass extends between the document insertion port and the document discharge port.

A scanner (optical system) for reading an image recorded on a document as optical information is disposed below the platen glass. There are two modes for reading an image of a document using this scanner: a fixed reading mode for reading an image while the document is fixed on a platen glass;
There is a movement reading mode (sheet-through mode) for reading an image while moving a document on the platen glass in the transport direction.

In the fixed reading mode, a document (recording) is recorded on an original while moving the scanner (optical system) in the above-described conveying direction or in the opposite direction with the original fixed to the predetermined fixed reading position with the original fixed. In this mode, an image is read by a scanner. On the other hand, the sheet-through mode is a mode in which an image recorded on the original is read by the scanner while the original is moved in the above-described transport direction with the scanner fixed.

In the fixed reading mode, the image of the document is read while the document is fixed on the platen glass.
Part of the image of the document larger than the platen glass cannot be read. Therefore, the fixed reading mode cannot be applied to a document larger in size than the platen glass. On the other hand, in the sheet-through mode, since the image of this document is read while moving the document on the platen glass, it can be applied to a document larger in size than the platen glass.

[0008]

By the way, in the sheet-through mode, the original is sometimes electrostatically attracted to the platen glass for a moment, for example, and the original cannot be moved smoothly on the platen glass. When the frictional force between the document and the platen glass is smaller than the frictional force between the document and the transport belt, the document is smoothly transported and moved on the platen glass. However, the magnitudes of these frictional forces may be reversed for some reason. In this case, the document is not smoothly conveyed on the platen glass.

If the document is not conveyed smoothly on the platen glass, the image read by the scanner may be extended or contracted. For this reason, the image formed on the recording paper based on the image information from the scanner may be expanded or shrunk as compared with the image recorded on the document, resulting in a defective image.

In view of the above circumstances, it is an object of the present invention to provide an image reading apparatus capable of stably and smoothly transporting an original, and an image forming apparatus incorporating the image reading apparatus.

[0011]

According to a first image reading apparatus of the present invention for achieving the above object, a document insertion slot into which a document is inserted and a document inserted through the document insertion slot are discharged. A document discharge port, a platen glass extending from the document insertion port to the document discharge port, and a document inserted from the document insertion port coming into contact with the upper surface of the platen glass from the document insertion port. An image reading apparatus for reading an image recorded on a portion of the original which is in contact with the original platen glass, wherein: (1) the original insertion opening; And a pressing member disposed near the document insertion slot for pressing a document inserted from the paper feeding belt against the transport belt. Here, (2) the pressing member may be a flat pressing member that presses against a portion of the transport belt near the document insertion port.

(3) The pressing member may be a flexible member pressed against a portion of the transport belt near the document insertion port by a bending force.

Further, the image reading apparatus may further include (4) an elastic member which supports the flexible member and is disposed on a side opposite to the transport belt with the flexible member interposed therebetween.

According to a second image reading apparatus of the present invention for achieving the above object, there is provided a document insertion port into which a document is inserted, a document discharge port through which the document inserted from the document insertion port is discharged. A document table glass extending from the document insertion port to the document discharge port, and a document inserted from the document insertion port to the document discharge port while the document inserted from the document insertion port contacts an upper surface of the document table glass. And a transport belt that transports the document in the transport direction toward the document, while fixing the document inserted from the document insertion port at a predetermined fixed reading position on the platen glass and moving the scanner in the transport direction or the opposite direction. A fixed reading mode in which an image recorded on the document is read by the scanner, and while the scanner is fixed and the document inserted from the document insertion port is transported in the transport direction, (5) a press-contact position for pressing a portion of the transport belt in the vicinity of the document insertion opening from below, And a press-contact member selectively located at any one of a retreat position away from the transport belt.

In the above image reading apparatus, (6) the pressing member is located at the evacuation position in the fixed reading mode, and the pressing member is positioned in the pressing position in the moving reading mode. Switching means for positioning may be provided.

According to a third aspect of the present invention, there is provided an image reading apparatus, comprising: a document insertion port into which a document is inserted; a document discharge port through which the document inserted from the document insertion port is discharged; A document table glass extending from the document insertion port to the document discharge port, and a document inserted from the document insertion port to the document discharge port while the document inserted from the document insertion port contacts an upper surface of the document table glass. An image reading device for reading an image recorded on a portion of the original document that is in contact with the platen glass. (7) Inserting the original document in the transport belt A portion near the mouth is located above and separate from the platen glass, and (8) a rotating body that is pressed against the vicinity portion and is driven to rotate.

According to a fourth image reading apparatus of the present invention for achieving the above object, there is provided a document insertion port into which a document is inserted, a document discharge port through which the document inserted through the document insertion port is discharged. A document table glass extending from the document insertion port to the document discharge port, and a document inserted from the document insertion port to the document discharge port while the document inserted from the document insertion port contacts an upper surface of the document table glass. And a transport belt that transports the document in the transport direction toward the document, while fixing the document inserted from the document insertion port at a predetermined fixed reading position on the platen glass and moving the scanner in the transport direction or the opposite direction. A fixed reading mode in which an image recorded on the document is read by the scanner, and while the scanner is fixed and the document inserted from the document insertion port is transported in the transport direction, (9) In the image reading apparatus for selecting either one of the movement reading modes for reading an image recorded on a document by the scanner, (9) a portion of the document glass table near the document insertion port is pressed against the transport belt. It is characterized by being formed as described above.

According to a fifth image reading apparatus of the present invention for achieving the above object, there is provided a document insertion port into which a document is inserted, and a document discharge port through which the document inserted from the document insertion port is discharged. A document table glass extending from the document insertion port to the document discharge port, and a document inserted from the document insertion port to the document discharge port while the document inserted from the document insertion port contacts an upper surface of the document table glass. A transport belt that transports in the transport direction toward the scanner, and a scanner that is disposed below the platen glass and reads an image of a document. (10) The image reading apparatus for reading an image of an original by moving the original, wherein (10) a guide member for guiding the original to the original insertion slot is provided with a projection formed on a guide surface for contacting the original. It is intended to.

According to a sixth aspect of the present invention, there is provided an image reading apparatus, comprising: a document insertion port into which a document is inserted; a document discharge port through which the document inserted from the document insertion port is discharged. A document table glass extending from the document insertion port to the document discharge port, and a document inserted from the document insertion port to the document discharge port while the document inserted from the document insertion port contacts an upper surface of the document table glass. A transport belt that transports in the transport direction toward the scanner, and a scanner that is disposed below the platen glass and reads an image of a document. (11) a guide member for guiding a document to the document insertion opening, the guide member having an opening formed in a guide surface that comes into contact with the document; It is characterized in that between the upper and lower both than surface and a projecting member that moves freely through the opening.

Here, (13) the projection member is a moving reading mode for reading an image of the original by the scanner while fixing the scanner and transporting the original inserted from the original insertion slot in the transport direction. In the case of, it may be located above the guide surface.

(14) The projecting member may have a rotating body that rotates freely by contacting the original when the projecting member is located above the guide surface.

According to a seventh aspect of the present invention, there is provided an image reading apparatus, comprising: a document insertion slot into which a document is inserted; conveying means for conveying the document to the document insertion slot; A document exit from which the document inserted from the document exit is discharged, a document table glass extending from the document insertion port to the document document exit, and an upper surface of the document table glass for the document inserted from the document insertion port. And a transport belt that transports the document in a transport direction from the document insertion port toward the document discharge port while contacting the document, and reads an image recorded on a portion of the document that is in contact with the platen glass. In the apparatus, (15) a weakening means for gradually weakening a conveying force at which the conveying means conveys the document at a predetermined timing after the document starts being conveyed by the conveying belt is provided. Is shall.

Here, (16) the transporting means is a pair of rollers for transporting the document while nipping it, and (17) the weakening means is for relatively gradually separating the pair of rollers. Is also good.

(18) The weakening means may reduce the conveying force of the conveying means to zero before the image recorded on the document starts to be read.

Further, (19) the weakening means comprises (19)
-1) a supporting member that supports one of the pair of rollers; and (19-2) the one roller is gradually moved from the other roller by rotating the supporting member at a predetermined timing to move the supporting member. May be provided with an eccentric cam that separates from the eccentric cam.

According to another aspect of the present invention, there is provided an image forming apparatus, comprising: (20) any one of the above image reading apparatuses; and (21) an image read by the image reading apparatus on a recording medium. And an image forming unit.

[0027]

Embodiments of the present invention will be described with reference to the drawings. [First Embodiment] A first embodiment of an image reading apparatus and an image forming apparatus according to the present invention will be described with reference to FIG.

FIG. 1 is a perspective view showing a first embodiment of the present invention.

A document table glass 12 on which a document 100 (see FIG. 2) is placed is provided on a top surface of a copying machine (an example of an image forming apparatus according to the present invention) 10. A document feeder (DF) 80 for feeding the original 100 to the original platen glass 12 is fixed to the top surface so as to be freely opened and closed. The DF 80 also functions as a platen cover that covers the platen glass 12.

An operation unit (operation panel) 14 for inputting the number of copies and the like is arranged on the front side of the top surface of the copying machine 10. A power switch 16 for turning on the power of the copying machine 10 is arranged next to the operation unit 14. Also,
The copying machine 10 includes four cassettes 18, 20, 22, and 24 each containing a plurality of recording papers.
It is provided so that it can be freely inserted into and removed from the main body. The copying machine 10 also includes a manual feed tray 26 on which small-sized recording paper such as postcards can be placed, and a roll paper unit 28 that stores roll paper 28a (see FIG. 2). The copy machine 10 is provided with a paper discharge tray 30 on which recording paper on which an image is formed is stacked.

Referring to FIG. 2, the internal structure of the copying machine 10 shown in FIG. 1 and the procedure for forming an image will be described.

FIG. 2 is a schematic diagram showing the internal structure of the copying machine shown in FIG. In this figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

Below the DF 80 (see FIG. 1) in the closed state, a document table glass 12 on which a document 100 is placed is arranged. Under the platen glass 12, the original 10
An exposure optical system for irradiating 0 to obtain an image signal carrying image information is arranged. The exposure optical system includes a light source 32,
Lens 34 and mirrors 36, 38, 40, 42, 4
4, 46 and the like. The original 100 placed on the original platen glass 12 is irradiated with light from the light source 32, and the reflected light 48 from the original 100 is used as an image signal.
Lens 34 and mirrors 36, 38, 40, 42, 4
After passing through 4, 46, the light is irradiated on a photosensitive drum 50 arranged below the exposure optical system.

The photosensitive drum 50 has a rotating shaft 50a extending in a direction perpendicular to the plane of FIG. 2 and rotates in the direction of arrow A. A primary charger 52 for uniformly charging the photosensitive drum 50 is disposed upstream of the irradiation position of the reflected light 48 from the document 100 in the rotation direction of the photosensitive drum 50. The primary charger 52 allows the photosensitive drum 50
Is uniformly charged to form a charged surface, and then the reflected light 48 from the document 100 is irradiated on the charged surface to form an electrostatic latent image.

A developing device 54 for developing an electrostatic latent image is disposed downstream of the irradiation position in the rotation direction of the photosensitive drum 50. The area where the photosensitive drum 50 and the developing device 54 face each other is a development area where the electrostatic latent image is developed.
When the electrostatic latent image reaches the developing area by the rotation of the photosensitive drum 50, the developing device 54 develops the electrostatic latent image to form a toner image (developed image).

A transfer charger 5 for transferring a toner image onto recording paper is provided downstream of the developing area in the rotation direction of the photosensitive drum 50.
6 are arranged. Photosensitive drum 50 and transfer charger 56
Is a transfer area where the toner image is transferred onto the recording paper. When the toner image reaches the transfer area by rotation of the photosensitive drum 50, the toner image is transferred onto the recording paper conveyed to the transfer area. Is done.

The recording paper is stored in cassettes 18, 20, 22, and 2.
4 and roll paper unit 28, and are conveyed to the transfer area. When the recording paper is conveyed to the transfer area, for example, the cut paper 18a sent out from the cassette 18 by the paper feed roller 18b is made to stand by in a state in which a leading end thereof contacts a pair of registration rollers 60 to form a loop. In advance, the cut sheet 18a is transported to the transfer area at the timing when the toner image reaches the transfer area. Thus, the toner image is transferred to the cut sheet 18a.

When an image is formed on the roll paper 28a stored in the roll paper unit 28, the roll paper 28a
a pair of roll paper feed rollers 66 disposed above
Then, the roll paper 28a is conveyed to the registration rollers 60 while being held between the pair of roll paper conveyance rollers 68 disposed downstream of the pair of roll paper feed rollers 66 in the paper feeding direction, and is kept on standby. The roll paper 28a is transported to the transfer area at the timing when the toner image reaches the transfer area. As a result, the toner image is transferred to the roll paper 28a.

The cut paper 18a and the roll paper 28a to which the toner image has been transferred as described above are separated from the photosensitive drum 50 by the separation charger 58, and are conveyed to the conveyance belt 62 rotating in the direction of arrow B to be fixed. The fixing device 64 fixes the toner image on the recording paper. After the toner image is fixed on the recording sheet, the recording sheet is discharged to a discharge tray 30 from a discharge port (not shown). The residual toner remaining on the photosensitive drum 50 after the transfer is removed from the photosensitive drum 50 by the cleaning device 67. The residual charges remaining on the photosensitive drum 50 are discharged by a discharge lamp (not shown). As a result, the photosensitive drum 50 is ready for the next image formation.

In the copying machine 10 described above, a fixed reading mode for reading an image while the document 100 is fixed on the platen glass 12, and a sheet-through mode for reading the image while moving the document on the upper surface of the platen glass 12 in the transport direction. It is configured so that both modes can be selected. In the fixed reading mode, the document 100 is moved by the DF 80 to the platen glass 1.
2, the original 100 is temporarily stopped at a predetermined reading position on the upper surface, and the above-described exposure optical system is scanned to expose the original 100 to read an image of the original 100.
After the reading is completed, the document 100 is moved again and discharged. On the other hand, in the sheet through mode, the exposure optical system is stopped at a predetermined position on the
The document 100 is exposed while the document 100 is conveyed on the upper surface of the document table glass 12 by F80, and the image of the document 100 is read.

The structure and operation of the DF 80 will be described with reference to FIGS.

FIG. 3 is a perspective view showing a schematic configuration of a part of the DF.

The DF 80 has a document insertion port 82 into which the document 100 is inserted, and a document discharge port 84 through which the document 100 inserted through the document insertion port 82 is discharged. The document table glass 12 extends between the document insertion port 82 and the document discharge port 84. Also, DF8
0 indicates that the document 100 is inserted from the document insertion port 82 to the document discharge port 8
The transport belt 86 transports in the transport direction (the direction of arrow C) toward No. 4. The transport belt 86 is an endless belt made of urethane rubber, and its width (length in the direction perpendicular to the transport direction) is substantially equal to the width of the document table glass 12 (length in the direction perpendicular to the transport direction).

The transport belt 86 is provided with a belt driving roller 88 slightly above the document table glass 12 and near the document insertion port 82, and slightly above the document table glass 12 and near the document discharge port 84. Is stretched between the tension rollers 90 arranged in the, and is pulled so as not to be loosened. Between the belt driving roller 88 and the tension roller 90, a plurality of (three in FIG.
Is arranged. These transport rollers 92 press the transport belt 86 against the upper surface of the document table glass 12 using a spring or the like. For this reason, the transport belt 86
The original 100 can be transported in the transport direction while being in contact with the platen glass 12.

A paper feed guide plate 93 for guiding the document 100 between the transport belt 86 and the document table glass 12 is formed in the document insertion opening 82. The paper feed guide plate 93 extends in a direction orthogonal to the transport direction (the direction of arrow C).
Further, a plurality of pairs (four pairs in FIG. 3) of a pair of paper feed rollers 94 and 96 for conveying the document 100 while nipping the same are fixed to the rotating shaft 98 near the paper feed guide plate 93. A plurality of pairs of paper discharge rollers 106 for discharging the document 100 while nipping the document 100 are arranged in the document discharge port 84.

A pressing plate (also referred to as a conveying guide, which is an example of a pressing member according to the present invention) 102 for pressing the original 100 against the conveying belt 86 is disposed at a downstream portion of the sheet feeding guide plate 93 in the direction of arrow C. Have been. Pressing plate 102
Has substantially the same width as the width of the paper feed guide plate 93 (the length in the direction perpendicular to the direction of arrow C). The pressing plate 10
Reference numeral 2 denotes a plurality of transport rollers 9 which are continuous with the downstream end of the paper feed guide plate 93 in the direction of arrow C, and
2 and extend to the vicinity of the transport roller closest to the paper feed rollers 94 and 96. The downstream end of the pressing plate 102 in the direction of arrow C is located on the platen glass 12, and this position is set when the largest size original that can be used in the copying machine 10 is placed on the platen glass 12. The position is out of the way. In addition, the pressing plate 102 is rounded at the downstream end in the direction of arrow C, and the end and the transport belt 86 are hardly worn.

The pressing plate 102 is arranged so as to be pressed downward (toward the platen glass 12) by the transport belt 86. Therefore, the pressing plate 102 is in pressure contact with a portion of the transport belt 86 near the document insertion opening 82. The pressing plate 102 is made of a resin such as Mylar (an example of a flexible member according to the present invention) having a relatively low coefficient of friction with respect to the document 100 and having abrasion resistance.

When the original 100 is inserted into the original insertion opening 82 of the DF 80 having the above configuration, the inserted original 1
00 is first detected by a detection sensor (not shown).
Immediately after this detection, the paper feed rollers 94 and 96 start to rotate in the direction of arrow D, and the document 100 is nipped by the paper feed rollers 94 and 96. The original 1 with the rotation of the paper feed rollers 94 and 96
00 enters the gap between the conveyance belt 86 and the pressing plate 102, and further reaches the document table glass 12.

In this manner, the trailing end of the original 100 passes through the paper feed rollers 94 and 96 during or after the leading end of the original 100 passes through the original platen glass 12. As a result, the conveying force of the paper feed rollers 94 and 96 is
Does not reach. However, since the rear end of the original 100 is pressed between the transport belt 86 and the pressing plate 102 and is pressed against the transport belt 86, the transport force of the transport belt 86 reduces the original 1
It reaches to 00. For this reason, the original 100 is conveyed in the direction of the arrow C with a strong conveying force. Therefore, even if the original 100 is likely to be electrostatically adsorbed to the original platen glass 12, the original 100 is adsorbed and does not stop for a moment. , It is transported stably and smoothly. As a result, it is possible to prevent a trouble that the document 100 being conveyed is attracted to the document table glass 12 and stops for a moment, and it is also possible to prevent an image defect such as a stretched read image.

Note that the leading end of the original 100 is
When the sheet reaches No. 6, the leading end of the sheet is pinched by the sheet discharge roller 106 and discharged. When the document 100 is completely discharged, a discharge detection sensor (not shown) detects the document 100, and based on a discharge signal from the discharge detection sensor, the transport belt 86, the feed rollers 94 and 96, and the discharge The paper roller 106 and the like stop, and the document transport operation of the DF 80 ends. Second Embodiment A second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a side view schematically showing a portion of the DF included in the image reading apparatus of the second embodiment in the vicinity of the document insertion slot. In this figure, the same components as those shown in FIGS. 2 and 3 are denoted by the same reference numerals.

The image reading device of the second embodiment is a DF110
The DF 110 has a feature. Other structures are the same as the structure of the first embodiment. The DF 110 is characterized in that it has a pressure contact plate 112 (which is an example of a pressure contact member according to the present invention) in contact with the transport belt 86 and an elastic member 114 that supports the pressure contact plate 112 from below.

A press-contact plate (also referred to as a document transport guide) 112 for pressing the document 100 against the transport belt 86 is disposed at a downstream portion of the sheet feed guide plate 93 in the direction of arrow C. The press-contact plate 112 is positioned 1 mm from the upper surface of the platen glass 12.
上方 3 mm above. In addition, the pressing plate 11
2 has a moderate elasticity and a thickness of 200 to 400 μm.
m and sheet shape. The material is a resin such as Mylar, which has a relatively low coefficient of friction with respect to the document 100 and has abrasion resistance.

Further, the press contact plate 112 is
(The length in the direction orthogonal to the arrow C direction). Further, the press contact plate 112 is provided for the paper feed guide plate 9.
3, the paper feed roller 9 of the plurality of transport rollers 92 is connected to the downstream end in the direction of arrow C from the downstream end.
It extends to near the transport roller closest to 4,96.
The downstream end of the pressing plate 112 in the direction of arrow C is the original platen glass 1.
2 is positioned so as not to interfere with placing a document of the maximum size that can be used in the copying machine 10 on the platen glass 12. Further, the end of the press contact plate 112 on the downstream side in the direction of arrow C is rounded and inclined downward. Therefore, the end portion and the transport belt 86 are hardly worn. The pressing plate 112 is arranged so as to be pressed downward (toward the platen glass 12) by the transport belt 86. Therefore, the pressing plate 112 is pressed against the portion of the conveyor belt 86 near the document insertion opening 82.

An elastic member 114 such as a sponge is arranged below the pressure contact plate 112 (at a position opposite to the conveyor belt 86), and the pressure contact plate 112 is supported by the elastic member 114. Therefore, the pressing plate 112 is pressed against the transport belt 86 by not only the bending force of the pressing plate 112 but also the elastic force of the elastic member 114. Therefore, even if the press contact plate 112 is used for a long time, its plastic deformation is suppressed. As a result, as described later, the document 100 is reliably pressed against the transport belt 86 for a long period of time.

When the original 100 is conveyed, similarly to the DF 80 shown in FIG. 2, the original 100 is sandwiched between the pressing plate 112 and the conveyor belt 86, and the original 100 moves in the direction of arrow C with the rotation of the conveyor belt 86. Conveyed. In this case, as described above, not only the bending force of the press contact plate 112 but also the elastic member 11
Since the pressing plate 112 is pressed against the transport belt 86 by the elastic force of 4, the plastic deformation of the pressing plate 112 is suppressed, and the original 100 can be transported more stably and smoothly. As a result, the document 100 being conveyed moves to the platen glass 12.
Troubles such as being stopped for a moment by being absorbed by
An image defect such as a stretched read image can be more reliably prevented.

By the way, as shown by the two-dot chain line in FIG.
A configuration in which the press contact plate 112 (and the elastic member 114 in some cases) may be slid and accommodated inside the paper feed guide plate 93 may be adopted. With this configuration, the original can be stably and smoothly conveyed in the sheet-through mode as described above. On the other hand, in the fixed reading mode, the press contact plate 112 is housed inside the paper feed guide plate 93, so that the press contact plate 112 can be separated from the platen glass 12, so that it is not an obstacle. For this reason, a readable original of the maximum size can be placed on the original glass 12 without affecting the original readable area of the original glass 12.

Also, a sensor for detecting which of the sheet through mode and the fixed reading mode is selected, and the pressing plate 112 is slid out of the paper feeding guide plate 93 or housed therein. Switching device (which is an example of a switching means according to the present invention)
The image reading device 110 may be provided. When such a sensor and a switch are provided in the image reading apparatus 110, an image reading mode (sheet through mode or fixed reading mode)
, The position of the press contact plate 112 is automatically switched, so that there is no need for the user to perform this switching, and the image reading apparatus 110 that is easy to use can be obtained. Third Embodiment A third embodiment of the present invention will be described with reference to FIG.

FIG. 5 is a side view schematically showing a portion of the DF included in the image reading apparatus of the third embodiment in the vicinity of the document insertion slot. In this figure, the same components as those shown in FIGS. 2 and 3 are denoted by the same reference numerals.

The image reading apparatus according to the third embodiment has a DF 120
The DF 120 has a feature. Other structures are the same as the structure of the first embodiment. A feature of the DF 120 is that a transport roller 124 (an example of a rotating body according to the present invention) is rotatably fixed to a paper feed guide plate 122 for guiding the original 100 to the original table glass 12.

The portion of the transport belt 86 near the document insertion port 82 is located away from the document table glass 12 and above it. Further, the paper feed guide plate 122 is connected to the original insertion slot 8.
It extends from 2 to the vicinity of the downstream end of the document table glass 12 in the direction of arrow C while being inclined downward. About half of the lower part of this inclined surface is arranged close to the above-mentioned neighboring part.

Further, one 92a of the plurality of transport rollers 92 is close to the downstream end of the paper feed guide plate 122 in the direction of arrow C. In addition, a transport roller 124 is pressed by a spring (not shown) on an intermediate portion between the transport roller 92 a and the belt drive roller 88 which are close to each other in the transport belt 86. The plurality of transport rollers 124 are arranged at predetermined intervals in a direction orthogonal to the arrow C direction.

When the original 100 is inserted into the original insertion opening 82 of the DF 120 having the above-described configuration, the inserted original 100 is first detected by a detection sensor (not shown). Immediately after this detection, the paper feed rollers 94 and 96 are
The document 100 starts to rotate in the direction
Is sandwiched between. As the paper feed rollers 94 and 96 rotate, the leading end of the document 100 enters the gap between the conveyance belt 86 and the conveyance roller 124, and further reaches the document table glass 12.

In this way, the trailing end of the original 100 passes through the paper feed rollers 94 and 96 during or after the leading end of the original 100 passes through the platen glass 12. As a result, the conveying force of the paper feed rollers 94 and 96 is
Does not reach. However, since the rear end of the document 100 is sandwiched between the conveyance belt 86 and the conveyance roller 124 and pressed against the conveyance belt 86, the conveyance force of the conveyance belt 86 is transmitted to the document 100. For this reason, since the original 100 is conveyed in the direction of arrow C with a strong conveying force, even if the original 100 is likely to be electrostatically attracted to the platen glass 12,
It is stably and smoothly conveyed without being stopped for a moment after being sucked. As a result, it is possible to prevent a trouble that the document 100 being conveyed is attracted to the document table glass 12 and stops for a moment, and it is also possible to prevent an image defect such as a stretched read image. [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIG.

FIG. 6 is a side view schematically showing a portion of the DF included in the image reading apparatus of the fourth embodiment in the vicinity of the document insertion slot. In this figure, the same components as those shown in FIG. 5 are denoted by the same reference numerals.

The image reading apparatus according to the fourth embodiment has a DF 130 on a platen glass 132, and is characterized by the shape of the platen glass 132. Other structures are the same as the structure of the first embodiment.

The DF 130 is provided with a paper feed guide plate 134 for guiding the original 100 inserted through the original insertion opening 82 to the original platen glass 132. This paper feed guide plate 1
34 is formed only up to a slightly upstream side of the belt driving roller 88 in the direction of arrow C. However, a document table glass 132 is substantially continuous with the downstream end 134a of the paper feed guide plate 134 in the arrow C direction.

The original table glass 132 includes an original reading area 136 from which an image of an original is read, and a transport guide part 1 upstream of the original reading area 136 in the direction of arrow C.
38. The document reading area 136 has a shape similar to that of the conventional platen glass 12 (see, for example, FIG. 5).
On the other hand, the transport guide portion 138 is inclined so as to be in close contact with and press-contact with a portion of the transport belt 86 between the transport roller 92a and the belt driving roller 88.

Therefore, the document inserted from the document insertion port 82 is sandwiched between the document transport portion 132a of the document table glass 132 and the transport belt 86 after the trailing end of the document has passed the paper feed rollers 94 and 96. Transported in a state where As a result, almost all portions of the document placed on the document table glass 132 are pressed against the transport belt 86, and the transport force acts on the document directly almost uniformly. For this reason, a sufficient conveying force necessary for conveying the document can be obtained. Further, since the conveyance guide portion 138 of the document table glass 132 is separated from the document reading area portion 136, it does not hinder reading of the document. [Fifth Embodiment] A fifth embodiment of the present invention will be described with reference to FIGS.

FIG. 7 is a perspective view showing insertion of a document in the sheet through mode. FIG. 8 is a side view schematically illustrating the internal structure of the DF of the image reading apparatus according to the fifth embodiment. FIG. 9 is a side view schematically showing the document guide of the DF in FIG. FIG. 10 is a perspective view showing the document guide of the DF shown in FIG. In these figures, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

The DF 140 of the image reading apparatus according to the fifth embodiment
Is provided in the copying machine 10 instead of the DF 80 of the copying machine 10 (see FIG. 1). In DF140, the original 10
It is possible to select a fixed reading mode in which an image is fixed in a state where 0 is fixed to the platen glass 12 and a sheet-through mode in which an image is read while the document is moved on the upper surface of the platen glass 12 in the transport direction (the direction of arrow C). Is configured.

In the fixed reading mode, the original 100 is
40, the document 100 is fed to the upper surface of the platen glass 12, and the document 100 is temporarily stopped at a predetermined reading position on the upper surface.
The original 100 is exposed by scanning the above-described exposure optical system to read an image of the original 100. After the reading is completed, the original 100 is moved again and discharged. On the other hand, in the sheet through mode, as shown in FIG. 7, the DF 140 is closed and the exposure optical system is stopped at a predetermined position on the platen glass 12, and the document 10 is inserted through the document insertion port 142.
0 is inserted into the DF 140 to be fed into the DF 140, and while the original 100 is being conveyed on the upper surface of the original table glass 12, the original 100 is exposed to read an image of the original 100. In the sheet-through mode, the time required to read an image of a single document because the image of the document longer than the length of the document table glass 12 in the transport direction can be read and copied, and there is no need to reciprocally scan the exposure optical system. There is an advantage in that it can be shortened.

As shown in FIG. 8, the DF 140 has a document insertion port 142 into which the document 100 is inserted, and a document discharge port 144 through which the document 100 inserted through the document insertion port 142 is discharged. I have. A document input sensor 146 for detecting the presence or absence of a document is disposed slightly downstream of the document insertion port 142 in the document transport direction. A paper feed sensor 148 for detecting whether or not a document has been fed is arranged at a position slightly downstream of the document input sensor 146 in the document transport direction. An image sensor 150 that detects the leading edge (image tip) of the document is disposed slightly downstream in the document transport direction from the paper feed sensor 148. Further, a discharge sensor 152 for detecting a discharged document is disposed slightly upstream of the document discharge port 144 in the document conveying direction.

The DF 140 has a transport belt 154 for transporting the original 100 in the transport direction (the direction of arrow C) from the original insertion port 142 to the original discharge port 144. The transport belt 154 is an endless belt made of urethane rubber, and its width (length in the direction perpendicular to the transport direction) is substantially equal to the width of the platen glass 12 (length in the direction perpendicular to the transport direction).

The conveyor belt 154 includes a belt driving roller 156 disposed slightly above the document table glass 12 and in the vicinity of the document insertion port 142, and slightly above the document table glass 12 and in the vicinity of the document discharge port 144. Is stretched between the tension rollers 158 arranged in the, and is pulled so as not to be loosened. A plurality (three in FIG. 8) of conveying rollers 160 is arranged between the belt driving roller 156 and the tension roller 158. The plurality of transport rollers 160 are connected to the transport belt 154 using a spring or the like.
Is pressed against the upper surface of the platen glass 12. For this reason, the transport belt 154 transfers the document 100 to the document table glass 1.
2 can be conveyed in the conveying direction while being in contact with the sheet.

A pair of paper feed guide plates 162 for guiding the document 100 between the transport belt 154 and the document table glass 12 are formed in the document insertion port 142. The pair of paper feed guide plates 162 are provided on the upper guide plate 16 formed on the DF 140.
4 and a lower guide plate 166 formed on the main body of the copying machine 10.
Consists of These upper guide plate 164 and lower guide plate 166
Extends in a direction orthogonal to the transport direction (the direction of arrow C). A paper feed roller 168 is disposed at a central portion of the upper guide plate 164 in the transport direction, and an idle roller 170 is disposed at a central portion of the lower guide plate 166 in the transport direction. The paper feed roller 168 and the idle roller 170 convey the document 100 while nipping it.

Note that the original 100 is
A plurality of pairs of a pair of paper discharge rollers 172 and a pair of paper discharge rollers 174 that discharge the paper while nipping the paper are arranged. The document discharged by the discharge roller 172 is stacked on the upper surface of the DF 140, and the document discharged by the discharge roller 174 is stacked outside the DF 140.

As shown in FIG. 10, the idle rollers 170 are rotatably fixed to a plurality (six in FIG. 10) of the lower guide plate 166 at predetermined intervals in a direction perpendicular to the transport direction. Similarly, a plurality of upper guide plates 16 are provided at predetermined intervals in a direction orthogonal to the conveyance direction.
The upper surface 166a of the lower guide plate 166 (which is an example of the guide surface according to the present invention), which is located on the lower side, is slightly downstream of the idle roller 170 in the direction of arrow C and is orthogonal to the direction of arrow C. A pair of protrusions 176 are formed at the center in the width direction. When the document 100 is guided by the lower guide plate 166 on which the protrusion 176 is formed, the protrusion 17
6, the original 100 and the upper surface 166 of the lower guide plate 166.
A gap is formed between the two. Since the document 100 is conveyed to the platen glass 12 with the gap formed in this way, the gap is still formed between the portion of the platen glass 12 near the document insertion port 142 and the document 100. Become. If such a gap is formed, the original 10
The frictional force between the document 100 and the platen glass 12 is smaller than that in the case where the entire surface of the document 0 is in close contact with the platen glass 12.

Therefore, when the above gap is formed, the frictional force between the original 100 and the original platen glass 12 is determined by the frictional force between the original 100 being transported by the transport belt 154 and the transport belt 154. Is also small. As a result, the document 100 is reliably transported by the transport belt 154, so that the document 100 is transported stably and smoothly.
Therefore, it is possible to prevent a trouble in which the document 100 being conveyed is attracted to the document glass 12 and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated. Sixth Embodiment A sixth embodiment of the present invention will be described with reference to FIGS.

FIG. 11 is a side view schematically showing a DF of the image reading apparatus according to the sixth embodiment. FIG. 12 is a side view showing, on an enlarged scale, rollers and projections arranged in the DF of FIG. FIG. 13 is a block diagram showing main components constituting a copying machine provided with the image reading apparatus of the sixth embodiment. FIG. 14 is a schematic diagram showing transmission and reception of signals between the copying machine and the image reading device of FIG. FIG. 15 is a flowchart showing a procedure in the sheet through mode. In these drawings, the same components as those shown in FIG. 9 are denoted by the same reference numerals.

The DF 180 of the image reading apparatus according to the sixth embodiment
An opening is formed in the lower guide plate 182 of the paper feed guide plate 184, and the roller 186 (an example of a rotating body according to the present invention) protrudes from this opening, or the roller 186 is positioned below the lower guide plate 182. It is characterized in that it is configured to be retracted into. Note that the paper feed guide plate 184 holds the document 100 inserted from the document insertion port 142 on the transport belt 1.
It is guided between 54 and the platen glass 12.

As shown in FIGS. 11 and 12, the roller 186 is fixed to one end of a cam-shaped projection 188 so as to freely rotate about a rotation shaft 186a. The protrusion 188 is fixed below the lower guide plate 182 by a rotation shaft 188a, as shown in FIG. As described later, the protrusion 188 is driven by a stepping motor M902. This stepping motor M90
2 is controlled, whereby the lower guide plate 182 is controlled.
The height of the protrusion 188, that is, the height of the roller 186 is changed. Therefore, by changing the height of the roller 186 from the lower guide plate 182 in accordance with the thickness and material of the document, the friction between the document and the roller 186 causes the roller 18
6, the friction between the original and the platen glass 12 can be reduced, as described in the fifth embodiment.

The main parts of a copying machine equipped with the DF180,
A configuration for changing the height of the projection 188 will be described.

As shown in FIG. 13, the main body 200 of the copying machine stores a central processing unit (CPU) 202 for controlling the entire copying machine, a program executed by the CPU 202, data accompanying the program, and the like. ROM20
4 and a RAM 206 functioning as a temporary storage area for a work area and various data used by the CPU 202. Further, the main body 200 is also provided with an operation unit 208 and a display unit 210 which serve as an interface with the user.

Further, the main body 200 includes a copy paper transport section 212 including various paper feed rollers (not shown) for transporting the recording medium, a developing device 54 (see FIG. 1), and a fixing device 64.
The control unit 214 includes a control unit 214 for controlling the print medium (see FIG. 1), a path switching unit 216 for switching the conveyance path of the recording medium, a sensor group 218 having various sensors such as a document detection sensor, a power supply 220, and the like. Further, the light source 32, the lens 34, and the mirrors 36 and 3 shown in FIG.
An exposure optical system 230 composed of 8, 40, 42, 44, 46 and the like is incorporated.

As described above, the DF 180 has
In addition to the transport belt 154, a DF motor M901 that rotates the transport belt 154, a DF motor drive unit 194 that drives the DF motor M901, and the like are incorporated. Further, the DF 180 also incorporates a projection driving unit 196 for driving the above-described projection 188. Projection drive unit 196
Is composed of a stepping motor M902 for driving and rotating the projection 188, a stepping motor driving unit 198 for controlling and driving the stepping motor M902, and the like.

When a document is detected by the above-mentioned document input sensor 146, it is sent to the CPU 202 of the main body 200 as a DF document detection signal as shown in FIG. Similarly, when an original is detected by the paper feed sensor 148, as shown in FIG.
Sent to 2. Similarly, when the leading edge of the document is detected by the image sensor 150, the image is sent to the CPU 202 of the main body 200 as a DF image signal as shown in FIG. Similarly, when a document is detected by the paper ejection sensor 152,
As shown in FIG.
Sent to PU 202. The DF motor driving signal for driving the DF motor M901 and the stepping motor M
A stepping motor drive signal for driving the motor 902 is transmitted to the DF motor M901 and the stepping motor M902.

As described above, in the copying machine provided with the DF 180, either the fixed reading mode or the sheet through mode can be selected according to the size of the document. In this copying machine, when the main switch is turned on, the flow of FIG. 15 starts, and it is first determined whether or not the sheet-through mode is selected (S231). If the sheet-through mode has not been selected, this flow ends. If the sheet-through mode has been selected, the paper type of the document is selected by the user (S232). If the paper type is a special type (special type) such as the second original drawing paper, the height at which the protrusion 188 (see FIG. 11 and the like) protrudes above the lower guide plate 182 is set according to the paper type. Is done. The height (projection height) set in this case changes according to the paper type.

If it is determined in S232 that the paper is not special paper, that is, it is determined that the paper is plain paper, the projection 188 is not protruded (projection height is 0 mm). If it is determined in S232 that the sheet is a special type of paper, it is determined whether or not the sheet is the second original drawing sheet (S233). If it is determined in S233 that the sheet is the second original drawing sheet, the projection height is set to 3 mm (S241). On the other hand, when it is determined in S233 that the sheet is not the second original sheet (thin sheet), the protrusion height is 2 mm.
Is set to (S242).

After the projection height is set in this way,
When a document is inserted into the document insertion slot 142 (see FIG. 11), the document input sensor 146 detects the document, and about one second after that, the DF motor M901 rotates at a low speed and the paper feed roller 1 is rotated.
68 starts to rotate, whereby the document starts to be fed into the DF 180 (S234). Note that the projection 188 is activated (projected) after the leading edge of the paper has passed through the projection 188, instead of activating the projection 188 from the first half of the sheet feeding (state in which the tip of the paper hits the projection).

When the original conveyed in this way passes through the paper feed sensor 148 and is detected by the image sensor 150 (S235), the conveyor belt 154 starts rotating and the flow reading of the original starts. Then, the stepping motor M9
02 rotates forward, and the projection 188 (see FIG. 11 and the like) jumps out onto the lower guide plate 182 so as to have the height set in S241 or S242 (S236). Thereafter, it is determined whether or not the trailing end of the document is detected by the paper discharge sensor 152 (the paper discharge sensor 152 is turned off) (S23).
7).

When the paper ejection sensor 152 is off, the stepping motor M902 rotates in the reverse direction, and the projection 188 moves below the lower guide plate 182 to return to the original position (S23).
8). If the image sensor 150 does not detect the leading edge of the document in S235 and if the paper discharge sensor 152 is not turned off in S237, an error is generated (S2).
40), this flow ends.

As described above, the original is conveyed with the projection 188 projecting to a height corresponding to the paper type of the original, and the projection 188 causes the original and the upper surface 182 of the lower guide plate 182 to be conveyed.
b (see FIG. 11). Since the document is conveyed to the platen glass 12 with the gap formed in this manner, the document insertion opening 14
A gap is still formed between the portion close to 2 and the document. When such a gap is formed, the frictional force between the document and the platen glass 12 is smaller than when the entire surface of the document is in close contact with the platen glass 12.

Therefore, when the above gap is formed, the frictional force between the original and the platen glass 12 is smaller than the frictional force between the original being transported by the transport belt 154 and the transport belt 154. . As a result, the original document
Since the document is reliably transported at 54, the document is transported stably and smoothly. Therefore, it is possible to prevent a trouble in which the original being conveyed is attracted to the original platen glass 12 and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated. Seventh Embodiment A seventh embodiment of the present invention will be described with reference to FIGS.

FIG. 16 is a perspective view showing a lower guide plate of the seventh embodiment. FIG. 17 is a side view schematically showing a roller guide and a transport auxiliary roller. In these drawings, the same components as those shown in FIG. 11 are denoted by the same reference numerals.

The image reading apparatus according to the seventh embodiment is characterized in that a conveyance auxiliary roller 250 and a roller guide 252 are used instead of the roller 186 and the projection 188 of the sixth embodiment. Below the opening 182a formed in the lower guide plate 182, a U-shaped roller guide 252 is arranged. A transport auxiliary roller 250 is rotatably fixed to an upper end portion (a portion near the opening 182a) of the roller guide 252. On the other hand, the lower end of the roller guide 252 is
54 so as to be rotatable.

Further, a portion slightly below the central portion (bent portion) 252 a of the roller guide 252 is connected to the tip of the solenoid 256. One end 258a of the coil spring 258 is fixed to this connected portion, while
The other end 258b of the coil spring 258 is fixed to the main body of the image reading device. The coil spring 258 is disposed on the side opposite to the solenoid 256 with the roller guide 252 interposed therebetween, and urges the roller guide 252 to rotate in the direction of arrow E.

In the fixed reading mode (document fixed mode), the solenoid 256 is turned off, and the roller guide 252 is rotated in the direction of arrow E by the urging force of the coil spring 258. As shown in FIG. Auxiliary roller 25
0 is located below the opening 182a. On the other hand, in the sheet-through mode, the solenoid is turned on, and the solenoid 256 overcomes the urging force of the coil spring 258 to rotate the roller guide 252 in the direction opposite to the direction of the arrow E, thereby causing the conveyance assist roller 250 to open the opening 182a. Let out from.

In the sheet through mode, the transport assist roller 2
Since the document is conveyed in a state where 50 protrudes from opening 182 a, a gap is formed between the document and upper surface 182 b of lower guide plate 182 by conveyance auxiliary roller 250. Since the original is conveyed to the original platen glass 12 (see FIG. 11) in a state where the gap is formed as described above, the original is placed between a portion of the original platen glass 12 near the original insertion opening 142 (see FIG. 11) and the original. The gap also remains formed. When such a gap is formed, the frictional force between the document and the platen glass 12 is smaller than when the entire surface of the document is in close contact with the platen glass 12.

Therefore, when the above-mentioned gap is formed, the frictional force between the original and the original platen glass 12 is determined by the difference between the original being transported by the transport belt 154 (see FIG. 11) and the transport belt 154. Less than friction force. As a result, the document is reliably transported by the transport belt 154, so that the document is transported stably and smoothly. Therefore, it is possible to prevent a trouble in which the original being conveyed is attracted to the original platen glass 12 and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated. [Eighth Embodiment] An eighth embodiment of the present invention will be described with reference to FIGS.

FIG. 18 is a side view schematically showing the vicinity of a document insertion opening which is a characteristic part of the image reading apparatus according to the eighth embodiment. FIG. 19A is a perspective view showing the eccentric cam separated from the leaf spring, and FIG. 19B is a side view showing a state in which the eccentric cam has started to make one rotation and slightly depressed the leaf spring. c) is a side view showing a state where the leaf spring is slightly depressed before the eccentric cam completes one rotation,
FIG. 5D is a side view showing a state where the eccentric cam has rotated substantially halfway and the idle roller has been separated from the paper feed roller. FIG.
FIG. 19 is a top view of the back side of the image reading apparatus schematically showing the vicinity of a document insertion opening which is a characteristic part of the image reading apparatus according to the eighth embodiment. FIG. 21 is an enlarged top view showing the configuration of the eccentric cam and its vicinity. FIG. 22A is a side view illustrating a positional relationship between the control pipe and the solenoid, and FIG. 22B is a top view illustrating the control pipe and components near the control pipe. In these drawings, the same components as those shown in FIG. 9 are denoted by the same reference numerals.

The image reading apparatus according to the eighth embodiment is characterized by the structure of the DF. A specific point of this feature is that the paper feed roller 168 and the idle roller (paper feed roller) 170 that convey a document while nipping it are configured to gradually separate from each other at a predetermined timing. In order to achieve such a configuration, as shown in FIGS. 18 and 20, an idle roller 170 is rotatably fixed to the leading end of a leaf spring 300 having a fixed rear end. Support plate 30 below
The support plate 302 is moved up and down by an eccentric cam 304. These support plate 302 and eccentric cam 3
The movement of No. 04 will be described.

When a document detection sensor (not shown) arranged in document insertion port 142 and detecting the presence or absence of a document detects a document, motor 306 (see FIG. 20) starts rotating. This rotation is transmitted to the belt drive roller 156 by the belt 308 and the gear pulley 310, and the transport belt 154 starts rotating. The rotation of the motor 306 is controlled by the gears 310, 3
12 and 314 to the feed roller shaft 168a, whereby the feed roller 168 and the idle roller 17
0 starts to convey the document in the direction of arrow C while holding the document.

The gear 314 is engaged with the gear 316, and the gear 316 is attached to the control pipe 318. The control pipe 318 is fixed to the rotating shaft 318a with a set screw 322. The eccentric cam 304 is fixed to the rotation shaft 318a, and the rotation center axis of the eccentric cam 304 is the rotation shaft 318a. The above control pipe 31
8 incorporates a spring clutch (not shown), and the rotation of the gear 316 is controlled by the spring clutch.
8 or not. When the rotation from the gear 316 is transmitted to the control pipe 318, the eccentric cam 3
04 rotates around the rotation shaft 318a. On the other hand, when the rotation from the gear 316 is not transmitted to the control pipe 318, the eccentric cam 304 does not rotate.

As shown in FIG. 22, a projection 318b is formed on the outer peripheral surface of the control tube 318. Control tube 318
Is not rotated, the solenoid 32 is attached to the projection 318b.
The fourth claw 324a is configured to be hooked. On the other hand, when rotating the eccentric cam 304 by rotating the control pipe 318, the solenoid 324 is turned on and the claw 324a is separated from the projection 318b. The eccentric cam 304 and the spring clutch are incorporated in the DF, and are configured to operate when the DF covers the platen glass 12.
The weakening means according to the present invention includes an eccentric cam 304, a support member 302, and the like.

As described above, when the paper feed roller 168 and the idle roller 170 start nipping and transporting the document in the direction of the arrow C, the claw 324a of the solenoid 324
18b, the control pipe 318 and the eccentric cam 3
04 does not rotate. When the conveyance belt 154 rotates for a predetermined time after the document detection sensor detects the document, or when the document is conveyed by a predetermined distance, the solenoid 324 is used.
Is turned on. Thus, the eccentric cam 304 starts rotating.

Before the eccentric cam 304 starts to rotate, the eccentric cam 304 is separated from the support member 302 as shown in FIG. In this case, the paper feed roller 168 and the idle roller 170 sandwich the document and transport it in the direction of arrow C with a predetermined transport force. The eccentric cam 304 moves about 1 in the direction of arrow F.
When rotated by about 00 °, the eccentric cam 304 slightly pushes down the support member 302 as shown in FIG. 19B. As a result, the force for nipping the document between the paper feed roller 168 and the idle roller 170 is slightly reduced, and the conveyance force is also reduced.

Further, when the eccentric cam 304 rotates in the direction of the arrow F, as shown in FIG.
Pushes down the support member 302 further. As a result, the force with which the paper feed roller 168 and the idle roller 170 pinch the document is further reduced, and the conveyance force is further reduced. When the eccentric cam 304 rotates about 180 ° from the state shown in FIG. 18, the eccentric cam 304 is moved to the supporting member 3 as shown in FIG.
02 is completely depressed, and the idle roller 170 is completely separated from the paper feed roller 168. As a result, the conveyance force between the paper feed roller 168 and the idle roller 170 becomes zero, and the original is not conveyed by these rollers. The support member 302 is, as shown in FIG.
Are movably fixed to a sheet metal 326 to which the eccentric cam 304 is fixed, and when the eccentric cam 304 pushes down the support member 302, the support member 302 is pressed down uniformly at all portions.

As described above, with the rotation of the eccentric cam 304, the support member 302 is gradually pushed down, and the idle roller 170 is gradually separated from the paper feed roller 168. As a result, the conveying force between the sheet feeding roller 168 and the idle roller 170 also gradually decreases, and finally becomes zero. Therefore,
In the initial stage when the document is started to be conveyed, the document is conveyed by a predetermined conveyance force by the paper feed roller 168 and the idle roller 170. However, when the document is also conveyed by the conveyance belt 154, the paper feed roller 168 and the idle roller 170 The transfer force gradually decreases. For this reason, when a document passes through the paper feed roller 168 and the idle roller 170, it is possible to eliminate an impact (de-shock) caused by a sharp decrease in the conveying force.

As a result, since the brake does not appear to be applied during the conveyance of the document,
By 54, the image is conveyed stably and smoothly, and an image defect such that the read image is elongated is prevented. In the sheet-through mode, when a document is conveyed by the paper feed roller 168 and the idle roller 170 and also conveyed by the conveyance belt 154, the paper feed roller 16
8 and the conveyance speed by the idle roller 170 are slightly lower than the conveyance speed by the conveyance belt 154. For this reason, depending on the type of the original, when the original passes through the feed roller 168 and the idle roller 170, an image defect may occur such that the original is conveyed at a high speed and the image is read and the image shrinks. In the present embodiment, since the transport force is gradually weakened, an impact (de-shock) caused by a sharp increase in the transport speed can be more reliably eliminated.

When the conveyance force between the paper feed roller 168 and the idle roller 170 is reduced to zero (the idle roller 170 is completely separated from the paper feed roller 168) before the image recorded on the document starts to be read. After the image of the document is started to be read, the document is stably and smoothly conveyed by the conveyance belt 154, so that it is possible to prevent image defects such as expansion and contraction of the read image.

[0112]

As described above, according to the first image reading apparatus of the present invention, since the pressing member presses the document against the transport belt near the document insertion port, the contact area where the document contacts the transport belt is reduced. As the number of documents increases, the portion of the document pressed against the transport belt is also transported while contacting the transport belt. As a result, the document is conveyed with a strong conveyance force, so that the document is stably and smoothly conveyed. Therefore, it is possible to prevent a problem that the original being conveyed is attracted to the original platen glass and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated.

Here, when the pressing member is a flat pressure contact member that presses against the portion of the conveyance belt near the document insertion port, the document is sandwiched between the conveyance belt and the pressure contact member. Therefore, the document is more reliably pressed against the transport belt. As a result, the document is transported more stably and smoothly.

If the pressing member is a flexible member that is pressed against the portion of the transport belt near the document insertion port by a bending force, the pressing member is disposed between the transport belt and the flexible member. Since the original is pinched by the bending force, the original is more reliably pressed against the transport belt. As a result, the document is transported more stably and smoothly.

Further, if the flexible member has a rounded end at the downstream side in the transport direction, even if the transport belt contacts the downstream end of the flexible member, Since the ends are rounded, wear of these ends and the conveyor belt is suppressed. Therefore, an image reading apparatus having a long life and excellent durability can be obtained.

Further, when the image reading apparatus includes an elastic member which supports the flexible member and is disposed on the opposite side of the flexible member from the conveyance belt, the image forming apparatus has a flexible structure. Since the member is supported by the elastic member, the flexible member is brought into pressure contact with the transport belt by not only the bending force of the flexible member but also the elastic force of the elastic member. For this reason, even if the flexible member is used for a long time, its deformation is small. As a result, even if the image reading apparatus is used for a long period of time, the document is reliably pressed against the transport belt, so that the document is transported stably and smoothly.

According to the second image reading apparatus of the present invention, in the fixed reading mode, the pressing member is located at the evacuation position and is separated from the conveyor belt, so that the reading is performed without being disturbed by the pressing member. The largest possible original can be placed on the platen glass. In the moving reading mode, since the pressing member is located at the pressing position, the document is sandwiched between the conveyance belt and the pressing member.
Even in the vicinity of the document insertion slot, the document is reliably pressed against the transport belt. As a result, the contact area of the document with the transport belt increases, and the portion of the document pressed against the transport belt is transported while contacting the transport belt.
Therefore, the document is conveyed with a strong conveying force, so that the document is stably and smoothly conveyed. For this reason,
It is possible to prevent a problem that the original being conveyed is attracted to the original platen glass and stops for a moment, and also it is possible to prevent an image defect such as a stretched read image.

Here, the image reading device is provided with switching means for positioning the pressing member at the evacuation position in the fixed reading mode and for positioning the pressing member in the pressing position in the moving reading mode. In such a case, the position of the press-contact member is switched by the switching means in accordance with the reading mode, so that an easy-to-use image reading apparatus can be obtained.

Further, according to the third image reading apparatus of the present invention, in the vicinity of the document insertion slot, the rotating body presses the document inserted into the document insertion slot against the portion near the transport belt and presses it. For this reason, the contact area where the document contacts the conveyance belt increases, and the portion of the document pressed against the conveyance belt is conveyed while contacting the conveyance belt. As a result,
Since the document is transported with a strong transport force, the document is transported stably and smoothly. Therefore, it is possible to prevent a problem that the original being conveyed is attracted to the original platen glass and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated.

Further, according to the fourth image reading apparatus of the present invention, since the document glass table is pressed against the transport belt, the document inserted into the document insertion port is pressed against the transport belt and pressed. For this reason, the contact area where the document contacts the conveyance belt increases, and the portion of the document pressed against the conveyance belt is conveyed while contacting the conveyance belt. Therefore, the document is conveyed with a strong conveying force, so that the document is stably and smoothly conveyed. For this reason, it is possible to prevent a trouble in which the original being conveyed is attracted to the original platen glass and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated.

Further, according to the fifth image reading apparatus of the present invention, a gap is formed between the document and the guide member by the projection of the guide member. Since the document is conveyed to the platen glass through the document insertion port with the gap formed in this manner,
A gap is still formed between the document and the portion of the platen glass near the document insertion opening. When such a gap is formed, the frictional force between the document and the platen glass is smaller than when the entire surface of the document is in close contact with the platen glass. Therefore, when the above gap is formed, the frictional force between the original and the platen glass is smaller than the frictional force between the original being transported by the transport belt and the transport belt. As a result, the document is reliably transported by the transport belt, so that the document is transported stably and smoothly. Therefore, it is possible to prevent a problem that the original being conveyed is attracted to the original platen glass and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated.

Further, according to the sixth image reading apparatus of the present invention, the protrusion is formed on the guide surface by moving the protrusion member above the guide surface. In this case, a gap is formed between the document and the guide member by the projection member. Since the document is conveyed to the platen glass through the document insertion slot with the gap formed in this way, the gap is still formed between the portion of the platen glass near the document insertion slot and the document. Becomes When such a gap is formed, the frictional force between the document and the platen glass is smaller than when the entire surface of the document is in close contact with the platen glass. Therefore, when the above gap is formed, the frictional force between the original and the platen glass is smaller than the frictional force between the original being transported by the transport belt and the transport belt. As a result, the document is reliably transported by the transport belt, so that the document is transported stably and smoothly. Therefore, it is possible to prevent a problem that the original being conveyed is attracted to the original platen glass and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated. If the guide surface does not require a protrusion, the protrusion member is moved below the guide surface.

In the moving reading mode, the image of the original is read by the scanner while the original inserted from the original insertion port is transported in the transport direction while fixing the scanner. In the case of the moving reading mode (sheet through mode), if the document is located above the guide surface, there is a possibility that the document being conveyed is attracted to the platen glass and stopped for a moment. However, since the protruding member is located above the guide surface, the original is reliably and stably smoothly conveyed by the conveyance belt in the same manner as described above. Therefore, it is possible to prevent a problem that the original being conveyed is attracted to the original platen glass and stops for a moment, and it is also possible to prevent an image defect such that the read image is elongated.

Further, when the projecting member has a rotating body which freely rotates in contact with the document when it is located above the guide surface, the projecting member rotates when the document comes into contact with the rotating body. Since the body rotates, the frictional force between the projecting member and the document decreases. For this reason, the resistance when the transport belt transports the document is reduced, so that the document is transported more stably and smoothly by the transport belt.

Further, according to the seventh image reading apparatus of the present invention, the conveying force of the conveying means is gradually weakened by the weakening means, so that the conveying force of the conveying means does not suddenly weaken. For this reason, there is no possibility that the document being transported is braked. Therefore, the document is stably and smoothly conveyed by the conveyance belt. As a result, it is possible to prevent an image defect in which the read image is elongated.

Here, the transporting means is a pair of rollers for transporting the document while nipping the original, and the weakening means is configured to weaken the transporting means when the pair of rollers are relatively gradually separated from each other. Means can be simplified.

Further, if the weakening means is to reduce the conveying force of the conveying means to zero before the image recorded on the document is started to be read, after the image of the document is started to be read, The original is reliably and smoothly transported by the transport belt. As a result, it is possible to more reliably prevent an image defect such as a stretched read image.

Further, the weakening means comprises: a support member for supporting one of the pair of rollers; and a support member for rotating the support member at a predetermined timing to move the one roller to the other roller. And an eccentric cam that is gradually separated from the eccentric cam, a weakening means having a simple structure can be obtained.

Further, when the image reading device includes a driving source for rotating the eccentric cam and a spring clutch for transmitting the driving force of the driving source to the eccentric cam, the driving force of the driving source is transmitted to the spring clutch. Therefore, the image reading apparatus has a simple structure.

Further, according to the image forming apparatus of the present invention, since the above-described image reading apparatus is provided, an image forming apparatus free from image defects due to a document conveyance failure can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an internal structure of the copying machine shown in FIG.

FIG. 3 is a perspective view showing a schematic configuration of a part of a DF provided in the copying machine of FIG. 2;

FIG. 4 is a side view schematically illustrating a portion near a document insertion slot in a DF included in an image reading apparatus according to a second embodiment of the present invention.

FIG. 5 is a side view schematically illustrating a portion near a document insertion slot in a DF included in an image reading apparatus according to a third embodiment of the present invention.

FIG. 6 is a side view schematically illustrating a portion near a document insertion slot in a DF included in an image reading apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view illustrating insertion of a document in a sheet through mode.

FIG. 8 is a side view schematically illustrating an internal structure of a DF of an image reading apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a side view schematically showing a document guide of the DF in FIG. 8;

FIG. 10 is a perspective view showing a document guide of the DF in FIG. 8;

FIG. 11 illustrates a DF of an image reading apparatus according to a sixth embodiment of the present invention.
It is a side view which shows typically.

FIG. 12 is an enlarged side view showing a roller and a protrusion arranged on the DF in FIG. 11;

FIG. 13 is a block diagram showing main components constituting a copying machine provided with an image reading apparatus according to a sixth embodiment of the present invention.

FIG. 14 is a schematic diagram illustrating transmission and reception of signals between the copying machine and the image reading apparatus in FIG. 13;

FIG. 15 is a flowchart showing a procedure in a sheet through mode.

FIG. 16 is a perspective view showing a lower guide plate according to a seventh embodiment of the present invention.

FIG. 17 is a side view schematically showing a roller guide and a conveyance assist roller.

FIG. 18 is a side view schematically showing the vicinity of a document insertion slot, which is a characteristic part of the image reading apparatus according to the eighth embodiment of the present invention.

FIG. 19A is a perspective view showing an eccentric cam separated from a leaf spring, and FIG. 19B is a side view showing a state in which the eccentric cam has started to make one rotation and slightly depressed a leaf spring. (C) is a side view showing a state where the leaf spring is slightly depressed before the eccentric cam completes one rotation, and (d) is a side view showing
FIG. 4 is a side view showing a state in which the eccentric cam rotates substantially halfway and the idle roller is separated from the paper feed roller.

FIG. 20 is a top view schematically showing the vicinity of a document insertion opening which is a characteristic part of the image reading apparatus according to the eighth embodiment of the present invention.

FIG. 21 is an enlarged top view showing the configuration of the eccentric cam and its vicinity.

FIG. 22A is a side view showing a positional relationship between a control pipe and a solenoid, and FIG. 22B is a top view showing the control pipe and components near the control pipe.

DESCRIPTION OF SYMBOLS 10 Copier 12, 132 Document platen glass 80, 110, 120, 130, 140, 180 DF 82, 142 Document insertion port 84, 144 Document discharge port 86, 154 Transport belt 88, 156 Belt drive roller 90 , 158 Tension roller 92, 160 Transport roller 93, 122, 134, 162, 184 Paper feed guide plate 94, 96 A pair of paper feed roller 100 Document 102 Pressing plate 112 Press contact plate 114 Elastic member 124 Transport roller 168 Paper feed roller 170 Idle Roller 176 Projection 182 Lower guide plate 182a Opening of lower guide plate 186 Roller 188 Cam-shaped projection 250 Conveyance auxiliary roller 252 Roller guide 300 Leaf spring 302 Support plate 304 Eccentric cam 318 Control tube 318b Projection of control tube 324 Solenoid 32 Claws of a solenoid

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuo Tokuda 6-3-3, Shimorenjaku, Mitaka City, Tokyo Inside the Co., Ltd. (72) Inventor Yoshihide Ametani 6-3-3, Shimorenjaku, Mitaka City, Tokyo (72) Inventor Hironori Matsuzaki 6-3-3 Shimorenjaku, Mitaka-shi, Tokyo F-term (reference) in Copy Corporation 2H076 BA07 BA24 BA35 3F063 AA01 AB07 BA02 BA08 BA10 CA02

Claims (17)

[Claims] A document insertion port into which a document is inserted, a document discharge port through which the document inserted from the document insertion port is discharged,
A document table glass that extends from the document insertion port to the document discharge port, and a document inserted from the document insertion port is brought into contact with the upper surface of the document table glass from the document insertion port to the document discharge port. And a transport belt that transports the document in a forward transport direction, and reads an image recorded on a portion of the document that is in contact with the platen glass. An image reading apparatus, comprising: a pressing member that is pressed against a belt and is disposed near the document insertion port. 2. The pressing member according to claim 1, wherein the pressing member is a flat pressing member that presses against a portion of the conveyor belt near the document insertion port.
The image reading device according to claim 1. 3. The image reading apparatus according to claim 1, wherein the pressing member is a flexible member that is pressed against a portion of the transport belt near the document insertion port by a bending force. apparatus. 4. The apparatus according to claim 3, further comprising an elastic member that supports the flexible member and is disposed on a side opposite to the transport belt with the flexible member interposed therebetween. Image reading device. 5. A document insertion slot into which a document is inserted, a document discharge slot through which the document inserted from the document insertion slot is discharged,
A document table glass that extends from the document insertion port to the document discharge port, and a document inserted from the document insertion port is brought into contact with the upper surface of the document table glass from the document insertion port to the document discharge port. A transport belt that transports in the forward transport direction, while fixing the document inserted from the document insertion port at a predetermined fixed reading position on the platen glass, and moving the scanner in the transport direction or the opposite direction, A fixed reading mode for reading an image recorded on the document by the scanner, and while the scanner is fixed and the document inserted from the document insertion port is transported in the transport direction, the image recorded on the document is An image reading apparatus for selecting either one of a moving reading mode and a reading mode using a scanner, comprising: An image reading apparatus, comprising: a pressing member selectively positioned at any one of a pressing position where the pressing member presses the sheet and a retracting position away from the conveyance belt. 6. A switching means for positioning the pressing member at the evacuation position in the fixed reading mode and for positioning the pressing member in the pressing position in the moving reading mode. The image reading device according to claim 5, wherein: 7. A document insertion port into which a document is inserted, a document discharge port through which the document inserted from the document insertion port is discharged,
A document table glass that extends from the document insertion port to the document discharge port, and a document inserted from the document insertion port is brought into contact with the upper surface of the document table glass from the document insertion port to the document discharge port. And a transport belt for transporting the document in a forward transport direction, and an image reading apparatus that reads an image recorded on a portion of the document that is in contact with the platen glass. A portion of the transport belt near the document insertion port An image reading apparatus, comprising: a rotating body that is separated from and above the platen glass, and includes a rotating body that is pressed against the adjacent portion and is driven to rotate. 8. A document insertion port into which a document is inserted, a document discharge port through which the document inserted from the document insertion port is discharged,
A document table glass that extends from the document insertion port to the document discharge port, and a document inserted from the document insertion port is brought into contact with the upper surface of the document table glass from the document insertion port to the document discharge port. A transport belt that transports in the forward transport direction, while fixing the document inserted from the document insertion port at a predetermined fixed reading position on the platen glass, and moving the scanner in the transport direction or the opposite direction, A fixed reading mode for reading an image recorded on the document by the scanner, and while the scanner is fixed and the document inserted from the document insertion port is transported in the transport direction, the image recorded on the document is In the image reading apparatus for selecting either of the moving reading modes for reading with a scanner, a portion of the document glass table near the document insertion slot is the transporting mode. An image reading apparatus formed so as to be in pressure contact with a feeding belt. 9. A document insertion port into which a document is inserted, a document discharge port through which the document inserted from the document insertion port is discharged,
A document table glass that extends from the document insertion port to the document discharge port, and a document inserted from the document insertion port is brought into contact with the upper surface of the document table glass from the document insertion port to the document discharge port. A transport belt that transports the document in a forward transport direction, and a scanner that is disposed below the platen glass and reads an image of the document. An image reading apparatus for reading an image of an original by moving the original to an original, comprising a guide member having a projection formed on a guide surface for contacting the original and guiding the original to the original insertion slot. 10. A document insertion slot into which a document is inserted, a document discharge port from which the document inserted from the document insertion port is discharged, and a document table glass extending from the document insertion port to the document discharge port. And a transport belt that transports the original inserted from the original insertion port in the transport direction from the original insertion port toward the original discharge port while making the original inserted into contact with the upper surface of the original table glass. A scanner that is arranged and reads an image of a document, wherein the document reading device reads the image of the document by moving the document that is in contact with the upper surface of the platen glass relative to the scanner; A guide member having an opening formed in the guide surface to guide the document to the document insertion opening; and a projecting member freely moving through the opening both above and below the guide surface. Image reading apparatus characterized by comprising. 11. The moving reading mode for reading an image of a document by the scanner while fixing the scanner and transporting the document inserted from the document insertion port in the transport direction, The image reading device according to claim 10, wherein the image reading device is located above the guide surface. 12. The image forming apparatus according to claim 10, wherein the projecting member has a rotating body that freely rotates in contact with the document when the projecting member is located above the guide surface. The image reading device according to claim 1. 13. A document insertion slot into which a document is inserted, conveying means for transporting the document to the document insertion slot, a document discharge port from which the document inserted from the document insertion slot is discharged, and a document insertion slot. A document table glass extending from an opening to the document discharge port, and a conveying direction from the document insertion port to the document discharge port while the document inserted from the document insertion port is in contact with the upper surface of the document table glass. An image reading apparatus that reads an image recorded on a portion of the original document that is in contact with the original platen glass. An image reading apparatus comprising: a weakening unit that gradually weakens at a predetermined timing after the conveyance by the conveyance belt starts. 14. The apparatus according to claim 13, wherein said transport means is a pair of rollers for transporting the document while nipping it, and said weakening means is for relatively gradually separating said pair of rollers. The image reading device according to claim 1. 15. The apparatus according to claim 13, wherein the weakening unit sets the transporting force of the transporting unit to zero before an image recorded on a document starts to be read. Image reading device. 16. The weakening means includes: a support member that supports one of the pair of rollers; and a support member that is rotated at a predetermined timing to move the support member so that the one roller is the other roller. The image reading apparatus according to claim 14, further comprising: an eccentric cam that is gradually separated from the cam. 17. An image reading apparatus comprising: the image reading device according to claim 1; and an image forming unit configured to form an image read by the image reading device on a recording medium. Characteristic image forming apparatus.