JP2006217034A - Image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus provided with a positioning means directly positioned on a jump base that always maintains a positional relation between a skimming-through position and platen rollers over a whole main scanning range so as to prevent the occurrence of a defective image because the positional relation influences the occurrence of stripes, fogging, and blur or the like. <P>SOLUTION: The image reading apparatus with an original automatic feeder is provided, which includes the positioning means positioned at the jump base and a means for moving also in XY directions located to an opening/closing hinge mechanism. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading unit including a document feeding device that reads an image of a sheet material (document) on which an image is placed, such as a scanner, a copying machine, a printer, or a facsimile machine.

  2. Description of the Related Art Conventionally, some digital copying machines are provided with a document feeder such as a double-sided automatic document feeder. When copying a document in the document feeder with a digital copying machine equipped with this type of document feeder, a reading device provided below the document feeder is moved to a set position by a motor, that is, in the document feeder. After moving to a position just below the platen roller and stopping, light is emitted from the lamp unit, the original is transported between the platen roller and the glass plate, the original is scanned, and the reflected light is detected by the reading device It is supposed to be. A copy image is obtained by processing the detected data on the printer unit.

In the above conventional example, the attachment position of the document feeder varies due to variations in the parts of the document feeder or assembly, etc., and due to variations in the relative position between the reading setting position of the document feeder and the reader, There is a problem such as deterioration of image quality when reading a document. As a means for solving this problem, Japanese Patent No. 2993810 proposes a means for reading the platen roller while moving it in the sub-scanning direction with a reading device, and setting the position where the luminance is maximum to the reading position.
Japanese Patent Registration No. 2993810

  However, due to variations in parts or assembly of the document feeder, and by adjusting the inclination of the document feeder to align the main scanning line of the reading device with the document feeding direction of the document feeder, the platen of the document feeder is adjusted. The main scanning lines of the roller and the reading device are not parallel, and with the above method, good image quality cannot be obtained over the entire width in the main scanning direction. For example, in the above method, when the reading device reads the vicinity of the center in the longitudinal direction while moving the reading device in the sub-scanning direction, and the position where the luminance is maximized is set as the reading position, the obtained image is near the center in the main scanning direction. Gives a good image, but because the platen roller is tilted, there are image defects on both sides, such as an image that is out of focus due to the floating of the document, or a fogged image due to insufficient light quantity. .

  In the document feeder, toner, ink, and the like attached to the surface of the document being transported may be peeled off and collected on the platen glass. If these accumulated dust is present directly above the document reading position, the document reading unit may catch the dust as an image, and may erroneously recognize and read it as a streak image as a result. In contrast, since the gap between the platen glass and the platen glass is minimized by the platen roller, there is an effect of self-cleaning by rubbing the original conveying the accumulated dust. Is set near the platen roller, the generation of the streak image can be reduced. Therefore, if the platen roller is tilted with respect to the reading line in the main scanning direction, there is no problem with the image being read directly under the platen roller, but the above streak image is generated in the image being read away from the platen roller. There is a bug to do.

In order to achieve the above object, the invention according to the present application is
A document feeding means for feeding a sheet-like document;
Image reading means for reading an image of a document fed from the document feeding means;
For the image reading unit containing the image reading means,
Opening and closing means for supporting the document feeding means so as to be freely opened and closed;
A document whose image is read by the image reading means,
Comprising guide means for guiding to the automatic document feeder,
In an image reading apparatus with an automatic document feeder,
Positioning means for positioning the automatic document feeder on the guide means;
The opening / closing axis direction by the opening / closing means and the direction perpendicular to the opening / closing axis direction,
By providing the opening / closing means with a moving means that allows the automatic document feeder to move,
There is an effect that the positional relationship between the automatic document feeder and the reading device is always kept in a good state.

  As described above, the jump table that affects the flow-reading image has a positioning mechanism and a rotation hinge mechanism that can move linearly in the XY directions, so that the reading line and platen of the reader can be obtained. The relative positional relationship of the rollers is always ensured with high accuracy, and there is no defect in images such as streak images, out-of-focus, fogging, and blurring, and there is an effect of obtaining a good image.

Example 1
An image reading apparatus according to an embodiment of the present invention and a copying machine that is an image forming apparatus provided with the image reading apparatus in an apparatus body will be described with reference to the drawings.

[Explanation of the device]
In FIG. 1, a document feeder (automatic document feeder according to the present invention) 2 which is a sheet material conveying apparatus according to the present invention has a document tray 4 at the upper side, and a paper discharge tray 10 is disposed below the document tray. . The originals P on the original tray are sequentially separated and fed from the uppermost sheet one by one, and the original image is read while being conveyed. When the reading of the image is completed, the paper is stacked on the paper discharge tray 10.

  The copying machine main body 1 includes an image reading device 150 (hereinafter referred to as a reader unit) and an image output unit 300 (hereinafter referred to as a printer unit).

[Description of Reader]
The reader 150 includes a lamp 152 that irradiates light on the original surface, and mirrors 153, 155, and 156 that guide reflected light from the original P corresponding to the light emitted from the lamp 152 to the lens 157 and the CCD 158. is doing. The lamp 152 and the mirror 153 are attached to the first optical bench 159, and the mirrors 155 and 156 are attached to the second optical bench 151.

  The optical benches 159 and 151 are coupled to a motor 314 (not shown) by a wire 154 (not shown), and are moved and controlled in parallel with the document table glass 3 by the rotation of the motor 314.

  The position sensor 315 is a sensor for detecting the home position of the first optical bench 159, and moves the optical benches 159 and 151 by rotating the motor 314 forward and backward based on the position of the position sensor 315. The document on the platen glass 3 is optically scanned.

  The motor 314 is configured by a stepping motor. An encoder 302 (see FIG. 15) is connected to the motor 314, and the output of the encoder 302 can recognize how many pulses the optical benches 159 and 151 have moved. That is, the positions of the optical benches 159 and 151 can be grasped by encoder pulses from the position sensor 315 and the encoder 302.

  Reflected light from the original is guided to the lens 157 via the mirrors 153, 155 and 156, and is condensed on the CCD 158 by the lens 157. The CCD 158 photoelectrically converts the reflected light reflecting the document information and outputs it as an electronic image signal.

  Under such a configuration, in the state where the first optical table 159 is stopped at the document reading position 160, a document flow reading mode for reading document information while conveying the document by the document feeder 2, and the document on the document table glass 3. The document information can be read in two modes: a document table glass document fixed reading mode in which the document table is read while the optical tables 159 and 151 are moved in the sub-scanning direction.

[Description of printer section]
The printer unit 300 is an image forming unit that uses well-known electrostatic latent image image formation.
The printer unit, which is an image output unit 300, will be described with reference to FIG.

  Reference numeral 100 denotes an upper cassette. The sheets in the cassette are separated and fed one by one by the action of the separation claw and the feeding roller 101 and guided to the registration roller 106. Reference numeral 102 denotes a lower cassette. The sheets in the cassette are separated and fed one by one by the action of the separation claw and the feeding roller 103 and guided to the registration roller 106. A manual feed guide 104 guides the sheet material one by one to the registration roller 106 via the roller 105. A sheet stacking device (deck type) 108 includes a middle plate 108a that is moved up and down by a motor or the like. The sheets on the middle plate are separated and fed one by one by the action of a feeding roller 109 and a separation claw, and a conveying roller 110 is provided. Led to.

  Reference numeral 112 denotes a photosensitive drum, 114 denotes a developing device, 115 denotes a transfer charger, and 116 denotes a separation charger, which constitute an image forming unit.

  Reference numeral 117 denotes a conveyance belt that conveys a sheet material on which an image is formed, 118 denotes a fixing device, 119 denotes a conveyance roller, and 120 denotes a diverter. The image-formed sheet material is guided to the discharge roller 121 by the diverter 120 and conveyed into the sorter 122. The sorter 122 includes a non-sort tray 122a, a sort bin tray 122b, a non-sort tray discharge roller 122c, and a sort bin tray discharge roller 122d. The non-sort tray and the sort bin tray move up and down to sort the sheets one by one. Note that a discharge tray may be mounted instead of the sorter.

  In the case of duplex copying and multiple copying, the sheet after fixing is branched by the diverter 120 and conveyed by the conveying roller 201. In the case of duplex copying, the sheet is discharged to the intermediate tray 200 via the belts 202, 204, the pass 206, and the discharge roller 205. Is done. In the case of multiple copying, the sheet is discharged to the intermediate tray 200 by the diverter 203. Reference numerals 209 and 210 denote half-moon rollers for feeding the sheet, 211 denotes a separation roller pair, and 213, 214, and 215 denote conveyance rollers for conveying the sheet to the registration roller 106.

[Description of Document Feeder]
Details of the document feeder 2 will be described below with reference to the drawings.

[Description of Document Tray]
In FIG. 1, a document tray 4 is for stacking sheet-shaped documents P. A pair of width direction restricting plates are arranged on the document tray 4 so as to be slidable in the document width direction. By regulating the width direction of the documents P stacked on the document tray 4 by the width direction regulating plate, it is possible to ensure the conveyance stability during feeding.

[Description of separation unit]
A paper feed roller 5 is provided above the document tray 4. The paper feed roller 5 rotates as the separation conveyance roller 8 rotates and feeds a sheet document.

  The paper feed roller 5 normally takes a position retracted above the home position (solid line position in the figure) so as not to disturb the document setting operation. When the sheet feeding operation is started, the sheet descends to the dotted line position in the figure and comes into contact with the upper surface of the document P. Since the sheet feeding roller 5 is pivotally supported by an arm (not shown), the arm can be swung to move the sheet feeding roller 5 up and down.

  The separation pad 6 is disposed on the side opposite to the separation conveyance roller 8 and applies pressure to the separation conveyance roller 8 side.

  The separation pad 6 is formed of a rubber material or the like whose friction is slightly smaller than that of the separation transport roller 8. The separation pad 6 separates the originals P fed by the paper feed roller 5 one by one and feeds the paper by the separation transport roller 8.

[Description of transport unit]
The registration roller 12 and the registration driven roller 11 are registration means for aligning the leading ends of the documents fed by the separation unit. The registration rollers 12 and 12 are abutted against the nip portions of the stationary registration roller pairs 11 and 12, The loops are made to align the tips.

  Next, it is conveyed toward the platen glass 161 by the lead roller 22 and the lead driven roller 14. Further, it is conveyed by the lead discharge roller 23 and the lead discharge driven roller 16.

  Reference numeral 162 denotes a jumping table for scooping up the sheet from the flow reading platen 161. When the image reading is completed, the document is discharged onto the discharge tray 10 by the discharge roller 18.

  In the duplex mode, the paper is not discharged by the paper discharge roller 18 but is switched back, guided to the upper paper path, and conveyed toward the registration rollers 11 and 12. When the registration rollers 11 and 12 are reached, the back side of the document is read in the same manner as described above.

[Description of reading unit]
A platen roller 24 is arranged on the opposite side of the platen glass 161 for reading shown in FIG. The platen roller 24 is rotated at the same peripheral speed as the lead roller 22. The platen roller 24 is a rubber roller having a white surface, and is not affected by the roller surface during image reading even for a thin document that is easily transparent.

  The platen roller 24 is arranged with a slight gap with respect to the platen glass 161. The gap amount is about 0.2 mm to 0.5 mm. The platen roller 24 is pivotally supported by swingable arms 67 and 68 at both ends, and the arms 67 and 68 are urged against the platen glass 161 by a spring (not shown). Further, the gap is guaranteed by a part of the arms 67 and 68 being in contact with the platen glass 161. The configuration is such that the platen roller 24 softly escapes when a thick original enters.

  The reading position 60 is set immediately below the platen roller 24. The document P being conveyed is guided by the platen roller 24, but the document P takes an R-shaped locus with the position immediately below the platen roller 24 as the lowest position. The locus of the R-shaped document P is affected by the position of the platen roller 24. Directly below the platen roller 24, the document hardly floats, and there are no image defects such as out-of-focus and fog. The further away from the position just below the platen roller 24, the more the document floats from the platen glass 161.

  Therefore, if the readable area, that is, the reading position 60 is in the range from the reference numeral 61 to the reference numeral 65 with the platen roller center 63 as the center, there is no image defect such as out-of-focus or fogging.

  In addition, toner, ink, and the like attached to the surface of the document being conveyed may be peeled off and may accumulate on the platen glass 161. If these accumulated dust is present directly above the document reading position, the document reading unit may catch the dust as an image and, as a result, misrecognize and read it as a streak image. Since the gap between the platen glass 161 and the platen glass 161 is minimized, there is an effect of self-cleaning by rubbing the original conveying the accumulated dust. The gap becomes more prominent as it approaches the platen roller narrower. If there is a reading position 60 between the reference numerals 62 to 64, there is almost no possibility that a streak image is generated.

  In other words, by disposing the reading position 60 in the range of reference numerals 62 to 64, there is no occurrence of problems in the entire image including out-of-focus and fog.

  In addition, from the leading edge of the document, reading of an image is started and the leading edge of the document reaches the slope of the jump table 162 or the guide 130 and the guide 136 on the opposite side from the jump table 162 to the lead discharge rollers 23 and 16. Therefore, a slight load is applied to the leading edge of the document, and characters and other images may be read in a blurred manner (image blurring). The main cause is that the step between the position of the jump table 162 and the position of the guide 136 in the X direction is more than a predetermined distance, so that the step between the jump table 162 and the guide 136 becomes large, and the document delivery is not performed smoothly. Is mentioned. As will be described later, in the present invention, since it is possible to directly position on the jump table 162 that is a document guide, good image reading is performed without variation depending on the apparatus.

[Explanation of jump stand positioning mechanism]
In the present invention, a jump stand positioning mechanism is provided so that the reading position 60 is always arranged in the range from 62 to 64.

  FIG. 6 is a view showing a positioning mechanism that comes into contact with the jump stand 162. The position roller 132 that can rotate by contacting the slope of the jump table and the position roller 133 that can rotate by contacting the side surface of the jump table 162 and the platen glass 3 are the paper guide units 130 and 131 of the document feeder. Is held by a part of. Since the paper guide portions 130 and 131 are a part of the frame 70 (frame body) of the document feeder, and the platen roller 24 and the hinge portion are fixed, the positioning rollers 132 and 133 and the platen roller 24 are relative to each other. The positional relationship is guaranteed with high accuracy. Further, since the jump table 162 of the reader 150 is configured to contact the platen glass 3 and the flow reading glass 161, the relative positional relationship between the jump table 162 and the flow reading position 60 is guaranteed. Therefore, if the positioning rollers 132 and 133 are always in contact with the jump base, the positions of the platen roller 24 of the document feeder 2 and the reading 60 of the reader 150 are guaranteed.

  FIG. 7 is a view showing a state when the document feeder is closed. When the document feeder closes in the direction of the arrow 134 and the positioning roller 132 abuts against the slope of the jump table 162 and rolls, the document feeder moves in the direction of the arrow 135. When fully closed, as shown in FIG.

  FIG. 8 shows a top view. Since the positioning rollers 132 and 133 are disposed outside the document feed width and at two positions, the front side and the back side, the document feed is not hindered and the inclination of the document feed device is also corrected. As will be described later, since the left hinge 96 and the right hinge 95 are provided with a backlash mechanism, the left hinge 96 is movable in the X direction and the right hinge 95 is movable in the XY direction. Therefore, the positioning rollers 132 and 133 are always in contact with the jump stand 162, so that the X-direction position of the platen roller 24 and the X-direction position of the reading position 60 of the reader 150 are relatively accurately guaranteed. Further, the axial direction of the platen roller 24 and the main scanning reading line at the reading position 60 are parallel to each other without being inclined relatively and are accurately guaranteed.

[Description of hinge mechanism]
FIG. 9 is a side view showing details of hinge units 95 and 96 of the document feeder of the present invention, and FIG. 10 is a cross-sectional view.

  The document feeder 2 is covered with a frame cover (exterior component member) 70. The reader 150 is provided with a stage for placing a platen glass 3 for reading an image on the upper surface and reading an image of a placed document.

  The document feeder 2 has a hinge unit (hinge mechanism) attached to the frame 70 so that it can be opened and closed with respect to the platen glass 3. The hinge unit is rotatable about the fulcrum shaft 86 and is an opening / closing device for the document feeder 2. The hinge unit includes a lift arm 71, a lift shaft 72, a lower spring shaft 74, a hinge arm 73, a height adjusting screw 75, a damper holding spring 82, an oil damper 76, a fulcrum shaft 86, a hinge base 85, a lower spring holder 84, and a compression. A spring 81, a spring holder top 79, and a spring shaft top 78 are included.

  The fulcrum shaft 86 is supported by a hinge base 85, and the hinge base 85 is fixed to the reader 150. Further, since the hinge arm 71 is pivotally supported, the hinge arm 71 is rotatable with respect to the hinge base 85.

  Further, since the hinge arm 73 supports the lift arm 71 via the lift shaft 72, the lift arm 71 is rotatable with respect to the hinge arm 773.

  The height adjustment screw 75 is fixed to the lift arm 71, but can be moved forward and backward, and the tip abuts against a part of the hinge arm 73 so that the height of the document feeder 2 relative to the platen 3 can be adjusted.

  The lift arm 71 is fixed to the frame 70 of the document feeder 2 and supports a spring shaft 78. The upper spring shaft 78 supports the upper spring holder 79.

  The upper spring holder 79 holds the end of the compression spring 81, and the lower spring holder 84 is arranged on the opposite side to hold the other end of the compression spring 81. The lower spring holder 84 is pivotally supported by the lower spring shaft 74.

  Since the lower spring shaft 74 is fixed to the hinge base 85, the distance between the upper spring shaft 78 and the lower spring shaft 74 is changed by the opening / closing operation of the document feeder 2, and the compression spring 81 expands and contracts accordingly.

  An end of a damper holding spring (compression spring) 82 is held under the spring holder 84, and an oil damper 76 is held on the opposite side. A boss 83 is disposed below the oil damper 76 and is guided to a guide 77 which is a part of the spring holder lower part 84, so that the oil damper 76 can be moved forward and backward.

  FIG. 14 is a cross-sectional view showing details of the oil damper 76. This is a known piston slide type viscous liquid damper. The upper and lower chambers in the figure in the housing 90 are filled with silicon oil having a predetermined viscosity. When a load is applied to the plunger 87, the piston 91 moves via the piston rod 89, and a minute gap with the housing 90 is obtained. As the silicone oil moves through the chamber through the damper, a damper resistance force is generated against the load applied to the plunger 87. When the load is released, the piston 91 is pushed up by the spring 92, and the oil moves from the hard ball 94 through the hole 97 to the lower chamber and returns to the initial state. The damper resistance increases in accordance with the speed at which the plunger 87 is moved. Therefore, the faster the document feeder 2 is closed, the greater the damper resistance.

  If the limit load of the oil damper 76 is P1, and a force exceeding P1 is applied to the plunger 87, the pressure of the oil filled in the oil damper 76 increases, and the housing 90, the piston rod 89, the piston 33, etc. There is a possibility of damage from the weakest point.

  The damper holding spring 82 is a compression spring that is elastically deformed from a free length state with a load P0 or more. The load P0 is set smaller than the limit load P1 of the oil damper 76.

  When a load of P0 or less is applied to the plunger 87, the damper holding spring 82 that holds the seating surface of the oil damper 76 does not elastically deform, and the plunger 87 of FIG. To retreat.

  When a load of P0 or more is applied to the plunger 87, the damper holding spring 82 is elastically deformed as shown in FIG. 12, so that the oil damper 76 retreats and releases the load, so that the load of P0 or more is applied to the oil damper 76. There is no participation. At this time, the plunger 87 does not retreat and no damper resistance force is generated, but a repulsive force is generated by the damper holding spring 82.

  As shown in FIG. 11, even when the document feeder 2 is closed at a speed that exceeds the load P0 from the opened position, the damper holding spring 82 absorbs the load, and the load applied to the oil damper 76 may exceed P1. This is effective in preventing the oil damper 76 from being damaged. On the other hand, the load during normal operation is P0 or less and a predetermined damper resistance force is generated, so that the document feeder 2 is quietly landed.

  In FIG. 13, when a thick original 88 having a height h, such as a dictionary, is placed on the platen glass 3, the lift arm 71 rotates relative to the hinge arm 73 to rotate the white pressure plate and the original feeder 2. Shows a state of equalizing parallel to the platen glass 3.

  FIG. 15 is a side view of the right hinge 95 and the left hinge 96, excluding content components such as the oil damper 76, the hinge base 85, the spring holder 84, the compression spring 81, the spring holder 79, and the spring shaft 78. It shows a state where it is opened by a predetermined angle. The document feeding device 2 is equalized in parallel to the platen glass 3 by rotating about the fulcrum shaft 86 and rotating the lift arm 71 about the lift shaft 72.

  FIG. 16 is a front view of the right hinge 95 and the left hinge 96, and is a view in which the content parts are omitted as in FIG. A compression spring 98 is disposed on the lift shaft 72 and urges the lift arm 71 in the axial direction. When the document feeder is opened, the document feeder fixed to the lift arm 71 is biased to the right in the X direction by the action of the compression spring 98. When the document feeder 2 is closed, as described above, the jump table 162 positioning mechanism approaches the left side in the X direction, and positioning is guaranteed at a predetermined position.

  FIG. 17 shows a perspective view of the right hinge 95. By configuring the bearing portion of the lift shaft 72 with the long hole 99 in the Y direction, the right hinge 95 can move in the Y direction as well as in the X direction. When the document feeder is opened to some extent, the lift shaft 72 is moved toward the end of the long hole 99 and regulated by its own weight. When the document feeder is closed, the above-described jump stand positioning mechanism moves to the left in the X direction simultaneously with the movement in the Y direction, and the lift shaft 72 moves to the middle of the long hole. For example, even if the reading line 60 of the reader 150 and the platen roller 24 of the document feeder 2 are inclined due to component variations or the like, the X-direction moving mechanism of the left hinge 96 and the right hinge 95 are not displaced even in the X direction. By the XY direction moving mechanism, the original feeding device is closed, and the positioning correction is automatically performed with high accuracy.

  Further, for example, even if another document feeder is replaced in the market, the positioning is automatically corrected in the same manner.

  Therefore, since the reading position 60 can always be arranged in the range from 62 to 64, as described above, not only the streak image is reduced, but there is no occurrence of general problems such as out-of-focus and fog, which is good. Can be obtained.

[Description of drive system]
FIG. 3 is a diagram showing a drive system showing motors and solenoids for driving each roller and the like.

  The separation solenoid 57 drives the feed roller 5 to swing. The separation solenoid 57 is a keep solenoid that lifts and holds the paper feed roller 5 above the home position (solid line position in the figure) and holds it at a position that does not interfere with the original setting. During the paper feeding operation, the separating solenoid 57 is turned off with the keep power turned off, and the paper feeding roller 5 comes into pressure contact with the uppermost sheet of the sheet document on the document tray 4.

  The separation motor 51 is a stepping motor and rotationally drives the separation roller 8 and the paper feed roller 5 in the transport direction.

  The lead motor 53 is a stepping motor that drives the registration roller 12, the lead roller 22, the platen roller 24, and the lead discharge roller 23. Each roller is driven at a speed for reading the image of the conveyed document.

  The paper discharge motor 50 is a stepping motor that drives the paper discharge roller 18.

[Explanation of sensor]
The document tray 4 is provided with a document set detection sensor 40 which is a transmission type optical sensor that detects that a sheet document P is set.

  Further, a paper width detection sensor 44 for detecting the length in the width direction of the document bundle P set on the document tray 4 by detecting the position of the side guide is provided at the lower part of the document tray 4.

  Between the separation roller 8 and the registration roller 12, there is provided a registration sensor 7 which is a transmission type optical sensor for detecting a document, detects the leading edge of the separated and fed document, and the amount of contact with the registration roller 12 ( The timing to control the loop amount is detected.

  A read sensor 13 that is a reflection type optical sensor that detects a document is provided immediately after the read roller 22, and serves as a reference signal for image reading start timing in the reading unit 160.

  A paper discharge sensor 17 that is a transmissive optical sensor for detecting a document is provided immediately before the paper discharge roller 18 to detect a paper discharge timing and the like.

[Description of feeding operation]
When the original P on the original tray 4 is detected by the original set sensor 40, the paper feed roller 5 is lowered and comes into contact with the original bundle.

  When a copy condition is input at the operation unit of the copying machine and the start key is pressed, the document width sensor 44 on the document tray 4 detects the document size. Further, the holding of the separation solenoid 57 is released, and the original advances to the downstream portion under the feeding force of the paper supply roller 5.

  Next, the documents P that have advanced from the document tray 4 are separated one by one and conveyed to the downstream portion.

  The document P that has passed through the separation unit is conveyed by the registration roller 12 with the front end aligned by the registration roller 12.

  The leading end reaches the lead roller 22 and is conveyed toward the platen glass 161, and the image is read by the reading unit 160 while being conveyed by the platen roller 24 and the lead discharge roller 23.

  When the image reading is completed, the paper is loaded on the paper discharge tray 10 by the paper discharge roller 18.

  In the duplex mode, the paper is not discharged by the paper discharge roller 18 but is switched back, guided to the upper paper path, and conveyed toward the registration rollers 11 and 12. When the registration rollers 11 and 12 are reached, the back side of the document is read in the same manner as described above.

[Block explanation of control circuit]
FIG. 5 is a block diagram showing a circuit configuration of a control device of the document feeder according to the present embodiment. The control circuit is mainly composed of a microprocessor (CPU) 54, and various loads are connected to the input / output port of the CPU 54. Drive circuit and sensor signal are connected.

  The control circuit includes a RAM backed up by a battery (not shown) and a ROM storing control sequence software. Reference numeral 55 denotes a communication IC for controlling data communication with the copying machine main body.

  The separation motor 51, the read motor 53, and the paper discharge motor 50 are driven by each stepping motor driver. Each driver receives a phase excitation signal and a motor current control signal from the CPU 254.

  The separation solenoid 57 is driven by a driver, and its operation is controlled by a signal connected to the input / output port of the CPU 54.

  Various sensors, such as the registration sensor 7, the set sensor 40, the lead sensor 13, the paper discharge sensor 17, and the tray width sensor 44, are connected to the input port of the CPU 54 so that the behavior of the document and the behavior of the movable load in the apparatus are controlled. Used for monitoring.

(Example 2)
FIG. 18 is a sectional view of the periphery of the reading showing another embodiment. The positioning member 140 slidable in contact with the jump table slope 162 contacts the side surface of the jump table 162 and the platen glass 3 and is held by a part of the paper guide portion 130 of the document feeder. Since the paper guide unit 130 is a part of the frame 70 (frame body) of the document feeder and the platen roller 24 and the hinge unit are fixed, the relative positional relationship between the positioning member 140 and the platen roller 24 is accurate. Well guaranteed. Further, since the jump table 162 of the reader 150 is configured to contact the platen glass 3 and the flow reading glass 161, the relative positional relationship between the jump table 162 and the flow reading position 60 is guaranteed. Since the positioning member 140 is always in contact with the jump table by the X movement mechanism of the left hinge and the XY movement mechanism of the right hinge, the positions of the platen roller 24 of the document feeder 2 and the reading 60 of the reader 150 are guaranteed, and this embodiment is performed. As in the example, since the reading position 60 can always be arranged in the range of reference numerals 62 to 64, not only the streak image is reduced, but also a general image including focus blur and fog does not occur, and a good image is obtained. Can be obtained.

FIG. 3 is a diagram illustrating the configuration of an image reading apparatus and a document feeding apparatus according to the present embodiment. 1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment. FIG. 3 is a diagram illustrating a drive system of the document feeder according to the present embodiment. FIG. 3 is a detailed view of a document reading unit of the document feeder according to the present embodiment. FIG. 3 is a control block diagram of the document feeder according to the present embodiment. FIG. 3 is a detailed view of a positioning unit of the document feeder according to the present embodiment. FIG. 3 is a detailed view of a positioning unit of the document feeder according to the present embodiment. FIG. 3 is a plan view of a positioning unit of the document feeder according to the present embodiment. FIG. 4 is a diagram illustrating a hinge mechanism of the document feeder according to the present embodiment. FIG. 4 is a diagram illustrating a hinge mechanism of the document feeder according to the present embodiment. FIG. 4 is a diagram illustrating a hinge mechanism of the document feeder according to the present embodiment. FIG. 4 is a diagram illustrating a hinge mechanism of the document feeder according to the present embodiment. FIG. 4 is a diagram illustrating a hinge mechanism of the document feeder according to the present embodiment. FIG. 4 is a diagram illustrating a buffer mechanism of the document feeder according to the present embodiment. FIG. 3 is a side view for explaining a hinge mechanism of the document feeder according to the present embodiment. FIG. 3 is a front view illustrating a hinge mechanism of the document feeder according to the present embodiment. FIG. 3 is a perspective view for explaining a hinge mechanism of the document feeder according to the present embodiment. FIG. 5 is a detailed view of a positioning unit of a document feeder according to another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copier 2 Document feeder 3 Platen 24 Platen roller 95 Right hinge 96 Left hinge 132, 133 Positioning roller 160 Reading unit 161 Flow reading platen 150 Reader part 300 Printer part

Claims (4)

Image reading means for reading an image;
A document feeding unit including a document feeding unit that feeds a sheet-shaped document toward the image reading unit, and a document discharge unit that discharges the sheet document from the image reading unit;
Guide means for guiding from the image reading means to the document discharge section;
Images of sheets conveyed by the feeding unit and the paper discharge unit are
In the image reading device read by the reading means,
Positioning means for positioning the document conveying means on the guide means;
For the image reading means,
An opening / closing means for opening and closing the document conveying means;
The opening / closing means is in an opening / closing axis direction and a direction perpendicular to the opening / closing axis direction,
An image reading apparatus, wherein the document conveying means is configured to be movable.   The image reading apparatus according to claim 1, wherein the positioning unit is arranged on the near side and the far side outside the document feeding area in the main scanning direction.   The image reading apparatus according to claim 1, wherein the positioning unit is in contact with a reading surface of the reading unit.   The image reading apparatus according to claim 1, wherein the positioning unit is a rotatable rotating roller.

Images