JP2006109367A - Image scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image scanner which maintains dirt sticking prevention effect on coating as long as four times and is effective for both of adhesive dust and floating dust. <P>SOLUTION: The image scanner reads an image reading at a reading position on a first contact glass 54 to which coating processing is applied, while feeding an original by fixing a reading part 5, wherein when the first contact glass 54 reaches expiration in the life of coating durability, the coating glass can be utilized by rotating by half backwards from the front side of an operating unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus applied to a facsimile, a scanner, a copying machine, a multifunction machine, and the like.

As a conventional image reading apparatus, a sheet-through type apparatus is known in which an original is transferred in a sub-scanning direction and is read by a fixed reading unit (for example, see Patent Document 1).
According to this method, the document passes while contacting the first contact glass during reading, so it is inevitable that dust or the like attached to the image surface side of the document adheres to the first contact glass. When this deposit adheres to the reading position of the first contact glass, the influence appears in the read image signal, and the image is deteriorated.
The deposits such as dust on the first contact glass are only generated as black spots in the document reading image reading device, whereas in the case of the sheet-through reading device, the so-called black is connected in the sub-scanning direction. As a result, streaks are generated and the impact is much greater.
The types of foreign substances are roughly classified into floating systems and adhesive systems. The floating foreign matter is dust, paper dust, toner, etc., and the adhesive foreign matter is glue attached to the first contact glass on the original, and the original adheres to the first contact glass by passing the original. It is thought that the toner on the surface accumulates.
The floating foreign matter is removed by bringing the document into contact with the first contact glass. Also, as a measure against adhesive foreign matter, the first contact glass can be coated to prevent adhesion of foreign foreign matter to the surface of the glass, but when the original comes into contact with the first contact glass, the coating peels off. As a result, problems remain in the durability of the coating.
As a method for improving the durability of the coating, it is conceivable to simply reduce the contact force of the document to the first contact glass or convey the document without contacting the first contact glass. In such a configuration, since there is no power to remove the floating foreign matter, the floating foreign matter accumulates in the first contact glass, and there is a high possibility that it will lead to image degradation.
In the technique described in Patent Document 1, a water repellent coat or the like is applied to the first contact glass to prevent the adhesion of dirt.
JP 2001-27282 A

However, as the document comes into contact with the first contact glass, the coating is scraped, the effect of preventing the adhesion of dirt is reduced, and there is a high possibility that image degradation such as black stripes will occur.
Accordingly, an object of the present invention is to provide an image reading apparatus effective for both sticky and floating dusts, which lasts four times as long as the effect of preventing the coating from being adhered to dirt in consideration of the above situation. .

In order to solve the above-described problem, the invention according to claim 1 is an image reading apparatus that reads an image at a reading position on a first contact glass that is coated while fixing a reading unit and conveying a document. The first contact glass is configured to be interchangeable in the front-rear direction position.
The invention according to claim 2 has a coating process in which the first contact glass is turned upside down, and when the first contact glass reaches the durability life of the coating, the first contact glass is removed from the surface. The image reading apparatus according to claim 1, wherein the image reading apparatus can be used by being turned upside down.
According to a third aspect of the present invention, the first contact glass is usually fixed to the image forming apparatus main body with a double-sided tape or the like, and the adhesive surface such as the double-sided tape or the like of the first contact glass is attached. The image reading apparatus according to claim 1, which is not coated.

  According to the present invention, even if the durability of the coating is reached at the reading position, the coating surface is again moved to the reading position by rotating the first contact glass halfway from the front to the back of the operation unit. Therefore, it is possible to prevent image deterioration such as black streaks and to obtain high quality image quality.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention relates to a read original processing apparatus used in an apparatus for reading an image while conveying the read original to a fixed reading unit and conveying the read original at a predetermined speed.
FIG. 1 is a cross-sectional view showing a basic configuration of the ADF. FIG. 2 is a control block diagram of the ADF of FIG. FIG. 3 is a block diagram showing a circuit configuration of the second reading unit of FIG. The basic configuration, operation, and action will be described according to the embodiment.
1 to 3, an ADF includes a document setting unit 1 for setting a read document bundle, a separation feeding unit 2 for separating and feeding individual documents from the set document bundle, and a fed document. It is composed of a registration unit 3 that performs primary abutting alignment and a function that pulls out and conveys the document after alignment, and a turn unit 4 that turns the conveyed document and conveys the document surface toward the reading side (downward). The
The ADF also reads the front image of the document from below the first contact glass 54, the first reading transport unit 5 for reading the back image of the document after reading, the second reading transport unit 6 for reading the back side image of the document. A paper discharge unit 7 that feeds a completed document to the outside or a reversing unit, a reversing unit 8 that performs reversing for re-reading, a stack unit 9 that stacks and holds documents after reading, and a driving unit that drives these conveyance operations It is comprised from the drive parts 68-72 and the controller part 75 which controls a series of operation | movement.
The original bundle 13 to be read is set on the original setting table 10 with the leading end abutted against the position of the broken line of the original stopper 25, and the width direction of the original bundle 13 is set to the side guide 11 (not shown). Positioning in a direction orthogonal to the transport direction is performed by.
In this state, the document set detection filler 21 is displaced from the broken line position to the solid line position. As a result, the shielding of the document set detection sensor 28 is released, and when the document set is detected, the document set detection sensor 21 is detected via the I / F unit 74. A document set signal is transmitted to the main body control unit 73. In FIG. 1, reference numeral 55 denotes a second contact glass.
Further, the document length detection sensor 12 or 14 provided on the document table surface (a reflection type sensor or an actuator type sensor that can detect even one document) is used to approximate the length of the document in the conveyance direction. It is determined (a sensor arrangement capable of determining at least whether the document size is vertical or horizontal is necessary).
Thereafter, a document feeding operation is executed by a document feeding signal (a signal input from an operation unit (not shown) and instructed from the main body control unit to the controller unit 75 via the I / F unit 74) (a flowchart diagram to be described later). 4 to 6).

FIG. 4 is a flowchart for explaining the execution of the document feeding operation. FIG. 5 is a flowchart for explaining the execution of the document feeding operation following A in FIG. FIG. 6 is a flowchart for explaining the execution of the document feeding operation following B in FIG.
Referring to FIGS. 1 to 6, it is determined whether or not a document set is set on document set unit 1 (S1). If the document set is a document set, CW (forward rotation, clockwise direction) of drive unit (calling motor) 68 is determined. ) Driving (which is a stepping motor in the embodiment, but can also be realized with a solenoid) is started (S2). Next, it is determined whether or not the document stopper 21 is at the retracted position (S3).
Thereafter, the pickup roller 20 moves from the broken line position to the upper surface of the document indicated by the solid line position by the reverse drive of the drive unit (calling motor) 68 (S4), and is pressed by a predetermined force. The home position sensor 19 is a sensor for detecting the state of the pickup roller 20 and the document stopper 21.

Next, it is determined whether or not the pickup roller 20 is at the calling position (S5). If it is at the calling position, the calling motor 68 is stopped (S6). During the pressure contact operation of the pickup roller 20, when the number of documents is small, the drop impact sound of the pickup roller 20 is generated due to the large drop height and the small cushioning action of the document between the document setting table 10 and the pickup roller 20. A bug that becomes larger occurs.
As a solution, a concave roller relief is formed at the contact point of the document setting table 10 with the pickup roller 20 so that the pickup roller 20 does not strike the document setting table 10 directly.
Thereafter, after a predetermined time, a drive source (paper feed motor) 69 for driving the separation feeding unit 2 and the registration unit 3 is rotated in the CW (forward rotation) direction (S7), and the pickup roller 20 is rotated in the clockwise direction. Then, the uppermost sheet of the sheet bundle 13 is fed in the direction of the separation unit 2.
At this time, the paper feeding belt 23 is stretched around the belt pulleys 22 and 24 with a predetermined tension, and is in pressure contact so as to be wound around a separation roller 26 provided in an opposing manner. The separation roller 26 is friction driven via a torque limiter (not shown) having a predetermined magnitude of torque.
When the separation roller 26 is directly engaged with the paper feeding belt 23 or in a state of being engaged through one original, the separation roller 26 is rotated counterclockwise as the paper feeding belt 23 rotates.
In the unlikely event that a document enters between the sheet feeding belt 23 and the separation roller 26 by two or more sheets, the follower force is set to be lower than the torque of the torque limiter. Rotate in the clockwise direction to push back the excess document, preventing double feed.
The document separated into one sheet by the action of the sheet feeding belt 23 and the separation roller 26 is further fed by the sheet feeding belt 23, and the leading edge is detected by the abutting sensor 29 in the process of traveling through the sheet feeding path. It strikes against the pull-out roller 30 that has been stopped.
It is determined whether or not the abutting sensor 29 is on (S8). If the abutting sensor 29 is on, the abutting amount counting is started (S9). If it is not on, it is determined whether or not the jam detection time is over (S10), and if it is over, it is determined that the jam has not been reached (S11).

5, the calling motor 68 is rotated CCW (S12), it is determined whether the pickup roller 20 is at the retracted position (S13), and if it is at the retracted position, the calling motor 68 is stopped (S14). The original is fed a predetermined distance from the detection of the abutting sensor 29, and it is determined whether the count value is equal to the predetermined pulse (S15).
As a result, the drive of the paper feed belt 23 is stopped by reversing the drive unit (paper feed motor) 69 while being pressed against the pull-out roller 30 with a predetermined amount of bending (S16). Here, the drive unit (reading motor) 70 is rotated forward.
Next, it is determined whether or not the width size sensor is on (S17). If it is on, document width information is transmitted (S18). It is determined whether or not the mixed loading mode is off (S19). Is transmitted (S20).
At this time, by rotating the drive unit (calling motor) 68 in the CCW direction, the pickup roller 20 is retracted from the upper surface of the document and the document is fed only by the conveying force of the paper feed belt 23, so It enters the nip of the pair of upper and lower rollers, and the tip is aligned (skew correction).

Turning to FIG. 6, it is determined whether the nip-in sensor (tip detection sensor) 34 is on (S21). If it is not on, it is determined whether the jam detection time is over (S22). (S23).
If the nip-in sensor 34 is on, it is determined whether or not the registration sensor 40 is on (S24). If it is not on, it is determined whether or not the jam detection time is over (S25). ).
If the registration sensor 40 is on, the registration stop pulse count is started (S27), and it is determined whether the count value is equal to the predetermined pulse (S28). If the count value is equal, the paper feed motor 69 and the reading motor 70 are stopped. (S29) A registration stop is transmitted (S30).
Thereafter, the pull-out roller 30 is driven by the reverse rotation of the drive unit (paper feed motor) 69 to convey the document in the direction of the turn unit 4. Here, when the first sheet of the original bundle is fed to the registration stop position, the conveyance speed of the pull-out roller 30 is set higher than the reading speed.
The reading conveyance roller 43 is also driven at the same speed by a driving unit (reading motor) 70. In the case of the second and subsequent sheets, as will be described later, a form of first advance of the next original is taken.
Thereafter, the original is sent to the nip between the reading conveyance roller 43 and the pressure roller 35, stopped at a position where a predetermined pulse is conveyed from the detection of the registration sensor 40, and transmits a registration stop signal to the main body control unit 73. 73 waits for the input of a reading start signal from 73 (a signal transmitted when synchronization with transfer paper or preparation for storage in the image memory is completed).

FIG. 7 is a flowchart for explaining a document reading operation by inputting a reading start signal. FIG. 8 is a flowchart for explaining the operation following C in FIG. FIG. 9 is a flowchart for explaining the operation following D in FIG.
FIG. 10 is a flowchart for explaining the operation following E in FIG. FIG. 11 is a flowchart for explaining the operation following F in FIG. FIG. 12 is a flowchart for explaining the operation following G in FIG. FIG. 13 is a flowchart for explaining the operation following H in FIG. FIG. 14 is a flowchart for explaining the operation following I in FIG.
Next, an original reading operation is executed by inputting a reading start signal. In FIGS. 1 to 3 and FIGS. 7 to 14, first, it is determined whether or not the size mixed mode is set (S31).
If it is not the size mixed loading mode, the reading motor speed is set from the reading magnification (S32). The forward rotation of the reading motor 70 is started and the tip count is started (S33).
The document whose registration is stopped is sent to the image reading unit 5 by the reading conveyance roller 43 and the pressure roller 35 which are rotated by the normal rotation driving of the driving unit (reading motor) 70.
The driving speed of the driving unit (reading motor) 70 at this time is determined based on information transmitted from the main body control unit 73 to the controller unit 75 based on a reading magnification input from a main body operation unit (not shown).

In the reading conveyance unit 5, the document passes between the first reading glass 54 and the white background plate 51 arranged on the upper surface thereof with a predetermined interval. During this time, an image is read by a reading system (not shown), is electrically converted via a CCD, and is stored in a memory device (not shown).
The reading / conveying unit 5 is provided with a means for making the conveyance gap as narrow as possible and reducing the degree of freedom of the document as much as possible. As such a method, a method of projecting a flexible guide member from the inner surface of the reading entrance guide 42 toward the white background plate 51 and filling the gap is effective.
Further, the white background plate 51 is pressed with a predetermined elasticity on the first reading glass 54 with a gap of about 0.5 mm ± 0.2 mm, and errors in the reading depth direction are also suppressed.
The surface of the first reading glass 54 is treated with a surface active agent (silicon-based activator) so that the ink does not adhere or adhere to the surface. Further, the above-described flexible guide is extended to the vicinity of the reading point, and the original surface does not positively contact the reading glass 54 at the reading point position, and the front end of the original is located near the reading point of the first reading glass 54. A configuration is adopted that allows wiping (action of scraping off foreign matter on the glass surface at the tip).
In FIG. 7, it is determined whether the count value is equal to the surface predetermined pulse (S34). If equal, the front DF gate on is transmitted (S35), and it is determined whether or not the duplex mode is selected (S36).
If it is the duplex mode, it is determined whether the count value is equal to the surface predetermined pulse (S37). If equal, the front DF gate on is transmitted (S38), and it is determined whether the paper discharge sensor is on (S39).
If the paper discharge sensor is not on, it is determined whether the jam detection time is over (S40). If the time is over, the paper discharge is not reached (S41).

1 and 2, the timing at which the leading edge of the document reaches the reading section 5 is controlled by the pulse count of the driving section 70, and the surface DF gate signal indicating the surface image effective reading area in the sub-scanning direction at that timing. Send.
Thereafter, the document advances while being read, and is fed to the intermediate conveyance pressure roller 53 through the pickup guide 52. Since the pressure roller 41 and the intermediate conveyance pressure roller 53 are driven by the reading conveyance roller 43 in common, the feeding speed and the drawing speed are the same, which has the effect of reducing the occurrence of a delivery shock.
The document sent out from the first reading and conveying unit 5 by the intermediate conveying and pressing roller 53 is sent to the second reading and conveying unit 6, and the contact image sensor 58 arranged with the reading unit facing downward from the upper surface and the lower side, It passes between the pressing members 59 arranged on the reading surface of the contact image sensor 58 with a predetermined pressure and a predetermined interval.
In the double-sided mode, the timing at which the leading edge of the document reaches the contact image sensor 58 is controlled by the conveyance pulse count from the detection of the leading edge of the registration sensor 40, and the back side image effective reading area is transmitted to the contact sensor unit at the timing.
Based on this signal, the image of the surface corresponding to the back side of the document is read, electrically converted to the same as the front side, temporarily stored in the frame memory unit 81 shown in FIG. 3, and then transferred to the main body control unit 73. The pressing member 59a functions as a shading reference and as a white background plate.
If the paper discharge sensor 60 is on, it is checked whether the registration sensor 40 is off (S42). If it is not off, it is determined whether the jam detection time is over (S43), and a resist retention jam is detected (S44).
If it is OFF, the rear end count is started (S45), and it is checked whether the count value is equal to the surface predetermined pulse (S46). If it is equal, the surface DF gate ON is transmitted (S47), and it is determined whether or not it is the duplex mode. (S48).
If the duplex mode is selected, it is determined whether the count value is equal to the surface predetermined pulse (S49). If equal, the front DF gate on is transmitted (S50), and it is determined whether the paper discharge sensor is off (S51).
If the paper discharge sensor is off, a paper discharge completion is transmitted (S54). If the paper discharge sensor is not turned off, it is determined whether or not the jam detection time is over (S52). If the time is over, a paper discharge stay jam is determined (S53).

Next, in the size mixed mode (S31) of FIG. 7, as shown in FIG. 9, the reverse switching solenoid 72 is turned on (S55), the reading motor speed is set to the size reading speed (S56), The reading motor 70 is rotated forward (S57).
Next, it is determined whether or not the paper discharge sensor 60 is ON (S58). If it is not ON, it is determined whether or not the jam detection time is over (S59). If the time is over, the paper discharge is not reached (S60).
If the paper discharge sensor 60 is on in step (S58), the reverse motor 71 is rotated forward (S61). It is determined whether or not the paper discharge sensor 60 is off (S62). If it is not off, it is determined whether or not the jam detection time is over (S63).
Next, the reverse count is started and the reading motor 70 is stopped (S65). It is determined whether the count value is equal to the predetermined pulse (S66). If equal, the reverse switching solenoid 72 is turned off, the reverse motor 71 is reversely rotated (S67), and the reverse butting count is started (S68).

Moving to FIG. 10, it is determined whether or not the count value is equal to the predetermined pulse (S69). If the count value is equal, the reading motor 70 is rotated forward (S70). Next, it is determined whether or not the reverse sensor 84 is on (S71). If it is not on, it is determined whether or not the jam detection time is over (S72).
Next, it is determined whether or not the registration sensor 40 is ON (S74). If it is not ON, it is determined whether or not the jam detection time is over (S75). If the time is over, the reverse resist is not reached (S76).
If the registration sensor 40 is ON in step S74, the tip count is started (S77), and the reading motor speed is set as the reading magnification (S78). Next, it is determined whether or not the count value is equal to a predetermined pulse (S79). If the count value is equal, a back side DF gate ON is transmitted (S80), and the reverse switching solenoid 72 is turned ON (S81).
Next, it moves to FIG. 11 and judges whether it is a double-sided mode (S82). If the duplex mode is selected, it is determined whether the count value is equal to the predetermined pulse on the back surface (S83). If equal, the front DF gate on is transmitted (S84), and it is determined whether or not the paper discharge sensor 60 is on (S85).
If the paper discharge sensor 60 is not on, it is determined whether the jam detection time is over (S86). If the time is over, the paper discharge is not reached (S87). If the paper discharge sensor 60 is on, the reverse motor 71 is rotated forward (S88).
Next, it is determined whether or not the registration sensor 40 is off (S89). If it is not off, it is determined whether or not the jam detection time is over (S90).
If the registration sensor 40 is off, the rear end count is started (S92), and it is determined whether the count value is equal to the surface predetermined pulse (S93). If equal, back side DF gate off is transmitted (S94).

Turning to FIG. 12, it is determined whether the duplex mode is set (S95). If the duplex mode is selected, it is determined whether the count value is equal to the predetermined pulse on the back side (S96). If equal, the front DF gate off is transmitted (S97), and it is determined whether the paper discharge sensor 60 is on (S98).
If the paper discharge sensor 60 is not off, it is determined whether the jam detection time is over (S99). If the time is over, a paper discharge stay jam is detected (S100). If the paper discharge sensor 60 is off, then a reverse count is started and the reading motor 70 is stopped (S101).
It is determined whether the count value is equal to the predetermined pulse (S102). If equal, the reverse switching solenoid 72 is turned off, and the reverse motor 71 is reversely rotated (S103).
Moving to FIG. 13, the reading motor 70 is rotated forward (S104), it is determined whether the reverse sensor 84 is on (S105). If not, it is determined whether the jam detection time is over (S106). Reversal unachieved jam (S107).
Next, it is determined whether or not the registration sensor 40 is on (S108). If it is not on, it is determined whether or not the jam detection time is over (S109). If the time is over, the reverse resist is not reached (S110).
Subsequently, it is determined whether or not the paper discharge sensor 60 is on (S111). If it is not on, it is determined whether or not the jam detection time is over (S112). If the time is over, the paper discharge is not reached (S113).
Next, it is determined whether or not the registration sensor 40 is off (S114). If it is not off, it is determined whether or not the jam detection time is over (S115).
14, it is determined whether or not the paper discharge sensor 60 is off (S117). If it is not off, it is determined whether or not the jam detection time is over (S118). If the time is over, a paper discharge jam is detected (S119). If the paper discharge sensor 60 is off, a paper discharge completion is transmitted (S120).

FIG. 15 is a flowchart for explaining the next original advance operation. FIG. 16 is a flowchart for explaining the operation following J in FIG. Referring to FIGS. 1 to 3, 15 and 16, it is determined whether reading is in progress (S121). If reading is in progress, it is determined whether or not the butting sensor 29 is off (S122).
The paper is fed so that the next original passes the first reading position after passing the second original reading position. In the case of single conveyance, paper feeding is started so that the next original passes through the first reading position after passing through the third reading position of the preceding original.
Since the reading and conveying roller 43 during reading of the document image is driven by the driving unit (reading motor) 70 at a speed corresponding to the reading magnification instructed from the main body control unit 73, the conveying speed of the next original is the speed of the reading and conveying roller 43. At the same speed, it must be fed into the nip between the reading conveyance roller 43 and the pressure roller 35.
Therefore, when the trailing edge of the document being read passes through the abutting sensor 29, a pulse count for controlling the gap between the sheets is started, and the advance feeding of the next document is started while monitoring the progress of the trailing edge of the document being read. Then, the drive unit (calling motor) 68 is rotated forward (S123).
It is determined whether or not the pickup roller 20 is at the calling position (S124). If it is at the calling position, the calling motor 68 is stopped (S125). The pickup roller 20 is brought into pressure contact with the upper surface of the next original, and then the drive unit (paper feed motor) 69 is driven to rotate forward (S126), and is conveyed until it contacts the stopped pull-out roller 30.
It is determined whether or not the butting sensor 29 is on (S127). If it is not on, it is determined whether or not the jam detection time is over (S128). If the time is over, it is determined that the butting has not been reached (S129). If it is on, the abutting amount counting is started (S130). The calling motor 68 is rotated CCW (S131).
It is determined whether the pickup roller 30 is at the retracted position (S132). If the pickup roller 30 is at the retracted position, the calling motor 68 is stopped (S133). The document is fed by a predetermined amount from the detection of the abutting sensor 29, and it is determined whether the count value is equal to the predetermined pulse (S134). If equal, the process moves to FIG. 16 to stop the paper feed motor (S135).

Next, in FIG. 16, it is determined whether the inter-paper pulse count is equal to the predetermined pulse (S136). If equal, the paper feed motor speed is set to the first-out speed (S137). The CW rotation (reverse rotation) of the paper feed motor is started (S138). Next, it is determined whether the tip detection sensor 34 is on (S139).
Here, the position of the trailing edge of the document being read is calculated from the inter-paper pulse count value, and when a predetermined paper interval is advanced from the pull-out roller 30, the drive unit (paper feed motor) 69 is driven in reverse, and the pull-out roller 30 It is driven at a high speed as in the first sheet.
If the tip detection sensor 34 is not on, it is determined whether the jam detection time is over (S140). If the time is over, it is determined that the tip detection is not reached (S141).
If it is ON, the paper feed motor speed is made the same as the reading speed (speed of the reading conveyance roller 43) by the detection of the leading end detection sensor 34, or is reduced to the reading speed (S142).
Control pulses of the drive unit (reading motor) 70 until the trailing edge of the document passes through the leading edge detection sensor unit (more specifically, when the drive unit 70 is configured by a stepping motor or a brushless motor, When the drive unit 70 is constituted by a brush motor with an encoder, the encoder pulse) is counted.
By performing this operation between successive original sheets, it is possible to recover the time stopped by the original abutting operation and maintain a predetermined original interval.

In FIG. 16, as in FIG. 6, it is determined whether or not the registration sensor 40 is ON (S143). If it is not ON, it is determined whether or not the jam detection time is over (S144). (S145).
If the registration sensor 40 is ON, the registration stop pulse count is started (S146), and it is determined whether the count value is equal to the predetermined pulse (S147). If the count value is equal, the paper feed motor 69 and the reading motor 70 are stopped. (S148), a registration stop is transmitted (S149).
As described above, the timing of ending the front and back document reading areas is controlled by the pulse count from the time when the trailing edge of the document is detected by the registration sensor.
Thereafter, the original is discharged to the stack unit 9 by a pair of discharge rollers 61 and 62 including a discharge roller 61 and a discharge pressure roller 62. The paper discharge stacker 56 is configured to be high on the downstream side, and contributes to prevention of jumping out of discharged originals and improvement of stacking original alignment accuracy.
During continuous reading of a plurality of documents, the driving of the reading motor 70 is stopped by the registration stop operation by the first document advance (see FIGS. 15 and 16) rather than the document discharge completion timing. When the reading motor 70 restarts when the reading starts, the paper discharge completion signal is transmitted to the main body control unit 73 when the trailing edge of the document leaves the paper discharge sensor 60, and the process is completed.
When stacking small-size documents, the reversing switching claw 64 of the reversing unit 8 is switched to the state indicated by the broken line by the driving unit (reversing switching solenoid) 72 to convey the document to the reversing path, and the reversing discharge driving roller 65. And a pair of reverse conveying rollers 65 and 66 constituted by a reverse paper discharge driven roller 66 are discharged onto a small size dedicated stacker 57 configured as a part on the document stacker 56.
This improves the visibility after discharging a small-size document. Further, the document setting table 10 is configured so as to be able to retreat upward with the rotation fulcrum 28 as a center, thereby improving the stack document extraction performance.
Further, when the document is discharged, the operation of the reverse switching claw 64 is synchronized with the trailing end of the discharged document, and immediately after the original is discharged, the reverse switching claw 64 is rotated in the direction of the broken line by the drive unit (reverse switching solenoid) 72. The rear end of the discharged original is hit to control the remaining rear end of the discharged original.

The above is an overview of the processing for single-sided or double-sided originals with the same size original bundle. Next, processing of single-sided and double-sided originals when sizes are mixed will be described. When mixed sizes are used, the document lengths are mixed and cannot be determined by the document length detection sensors 12 and 14 on the table. Therefore, after separating the documents into one sheet, the trailing edge of the document is separated from the sheet bundle. The size can be determined only when it becomes completely independent.
For this reason, when it is desired to determine the document size before reading, the document path configuration is set to be more than ½ of the maximum document length between the first document trailing edge detection position after separation and the registration sensor position before reading. Must be set to length.
If this is satisfied, the document setting position needs to be greatly separated from the reading position, and there is a drawback that the part including the document table and the conveyance path becomes large and the entire apparatus becomes wide. Therefore, in order to make the apparatus small, it is necessary to devise a method for detecting the document length when mixed loading.
As a countermeasure, if the document size cannot be determined before the start of reading at the time of mixed loading, the reading is not performed at the first conveyance, the paper is passed only for reading the size, and the second reading is performed via the reversing unit. A method of simultaneously reading the front surface and the back surface when passing is used (see flow diagrams 9 to 14).
In this case, the conveyance operation until the first registration stop is the same as when a document of the same size is bundled, but the operation after receiving the read start signal transmitted from the main body control unit 73 (particularly, the discharge unit 7 and subsequent processing) is different. .

When the paper passes through the reading unit 5 and is discharged, the reverse switching claw 64 is moved in the direction of the broken line by the drive unit (reverse switching solenoid) 72 before the leading edge of the document protrudes from the pair of paper discharge rollers 61 and 62. Feed the document to the reverse path.
Thereafter, the original is fed by the reverse discharge roller pair 65 and 66 driven by the drive unit (reverse motor) 71 until the rear end of the original passes the discharge roller pair 61 and 62. This control is performed by pulse count from the paper discharge sensor 60.
After the document is stopped, the reverse switching claw 64 is moved in the solid line direction by the driving unit 72 so that the rear end of the document is directed in the nip direction of the reverse conveying roller. Thereafter, the reverse paper discharge driving roller 65 rotates in the counterclockwise direction and stops, and the document end (initial stage) is placed at the nip portion of the reverse roller pair 61 and 63 composed of the paper discharge drive roller 61 and the reverse upper roller 63. When viewed from the state, the rear end is abutted, and the tip skew matching operation is performed.
Thereafter, the reverse roller pair 61, 63 starts feeding by the drive unit (reading motor) 70, and is sent again to the first reading transport unit 5 and the second reading transport unit 6 through the turn unit 4, and reading of the front and back sides is performed. .
At this time, since the document is in a state where the back side and the front side are reversed, the reading order is the back side and the front side is read later, so the back side gate on signal is transmitted first, and then the front side gate signal on signal is transmitted. . Based on this signal, the page order is changed on the image processing apparatus side.
Thus, the reading operation is completed, but if it is discharged as it is, the page order will be out of order. In addition, the conveyance for only the size reading and the conveyance for only the page alignment are configured so as to be sent at the highest conveyance speed of the apparatus for the conveyance operation not involving reading of the image, thereby reducing the loss time. (S104 to S119).

Next, a configuration that does not include the second reading conveyance unit 6 will be described. Although FIG. 1 shows a configuration having a contact image sensor 59 for both-sided documents, this reading device is expensive, and even if a configuration without this device is used, both-side document processing is performed using a reversing mechanism. Is possible. This type is expected to increase in actual products.
The original whose surface has been read by the reading operation in the first reading and conveying unit 5 is conveyed to the first reading and conveying unit 5 again through the reversing unit 8 to read the back surface, and then page alignment is performed. Is then discharged onto the document stacker 56.
As described above, in an apparatus having no second reading / conveying unit 6, productivity is lowered when a double-sided copy is made from a double-sided original. As a countermeasure, a method is adopted in which a plurality of originals are fed into the unit, and image reading and original reversal discharge are alternately combined to reduce a paper loss.
First, the first original is fed, and one page image reading is executed by the first reading and conveying unit 5, which is fed into the reversing unit and abutted and aligned with the pair of reversing rollers 61 and 63. The image is sent to the reading conveyance unit 5 and the second page is read.
In order to arrange the page order at the time of paper discharge, it is sent to the reversing unit, before and after this, the second original is fed, and the first reading conveyance unit 5 reads the third page. Subsequently, reverse discharge of the first original is executed. Subsequently, the fourth page of the second original is read.
Thereafter, the second original is sent to the reversing unit, and the third original is sent before and after this to read the fifth page. Subsequently, the second original is reversed and discharged. In this way, by performing the processing between the reverse reading operation of the document that has already been read between the front side reading and the back side reading, the paper loss time of the reverse discharging operation without reading is minimized. It is possible to stay.
Note that this processing is possible only for a document having a size that fits between the pair of reverse conveyance rollers 65 and 66 and the registration sensor 40.

Next, FIG. 17 is a schematic view showing the relationship between the first contact glass and the reading position. FIG. 18 is a schematic diagram for explaining the removal of the coating of the first contact glass. FIG. 19 is a schematic view showing an embodiment in which the first contact glass is half-rotated. FIG. 20 is a schematic view showing an embodiment in which the first contact glass is turned upside down.
Although a technique for forming a coating layer (fluorine-based, silicon-based, etc.) 54A on the first contact glass 54 to prevent the adhesion of dirt is known, the coating is applied when the original comes into contact with the first contact glass 54. There is a high possibility that the layer 54A is scraped, the effect of preventing the adhesion of dirt is weakened, and image deterioration such as black stripes occurs.
17 to 20, FIG. 17 shows the relationship between the first contact glass and the reading position. FIG. 18 shows a peeling portion 54a of the coating layer 54A that is generated when the document comes into strong contact.
In the present invention, the first contact glass 54 is supported so as to be attachable / detachable and changeable immediately above the reading position, and the front and back directions of the first contact glass are changed with respect to the support portion immediately above the reading position. It is configured to be interchangeable.
When the durability of the coating layer 54A is reached due to the contact with the document, as shown in FIG. 19, the first contact glass 54 is rotated halfway from the front to the back of the operation unit to replace the peeling portion 54a of the coating. By using the surface 54b on which the coating remains, this portion 54b can be brought to the reading position, and the adhesion of dirt can be prevented. That is, by changing the front and back without changing the front and back direction of the first contact glass 54, the portion 54b where the coating layer remains is arranged at a position immediately above the reading position.

Next, when the coating layer 54A on the surface of the first contact glass 54 reaches the end of its life, as shown in FIG. 20, the coating is again applied by turning over from the front surface of the first contact glass 54 to the back surface. The remaining surface 54b can be brought over the reading position. That is, in this example, the coating layers 54A and 54B are formed in advance on both the front and back surfaces of the first contact glass 54, and when one side is worn, the other side is used by reversing the front and back sides. Yes.
When a part of the coating layer 54B on the back surface reaches the end of its service life, similarly, the first contact glass 54 is used by rotating it halfway from the front direction of the operation unit to the back direction (reversing the front and back), thereby coating again. The remaining surface 54b can be brought to the reading position, and the total coating lasts 4 times, contributing to cost.
The first contact glass 54 is adhered and fixed to an image forming apparatus main body (not shown) with a double-sided tape or the like, but a portion to which an adhesive surface such as a double-sided tape or the like of the first contact glass 54 is attached (see FIG. When the coating process is performed, the first contact glass 54 and the adhesive surface do not adhere to each other. Therefore, the adhesive surface such as the double-sided tape of the first contact glass 54 should not be subjected to the coating process. And
According to the present invention, even when the durable life of the coating on the surface of the first contact glass 54 is reached at the reading position, the first contact glass 54 is turned over again from the front surface to the back surface, so that the reading position is restored. Therefore, it is possible to prevent image deterioration such as black streaks and obtain a high quality image quality.
Further, according to the present invention, since the coating process is not performed on the portion of the first contact glass 54 where the adhesive surface such as the double-sided tape is in contact, the first contact glass 54 and the image apparatus main body are bonded to each other with the double-sided tape or the like. Is possible.

Sectional drawing which shows the basic composition of ADF. The control block diagram of ADF of FIG. The block diagram which shows the circuit structure of the 2nd reading part of FIG. 6 is a flowchart for explaining execution of a document feeding operation. 5 is a flowchart for explaining execution of a document feeding operation following A in FIG. 6 is a flowchart for explaining execution of a document feeding operation following B in FIG. 5. 6 is a flowchart for explaining a document reading operation by inputting a reading start signal. The flowchart explaining the operation | movement following C of FIG. The flowchart explaining the operation | movement following D of FIG. The flowchart explaining the operation | movement following E of FIG. 11 is a flowchart for explaining an operation following F in FIG. 10. The flowchart explaining the operation | movement following G of FIG. The flowchart explaining the operation | movement following H of FIG. 14 is a flowchart for explaining the operation following I in FIG. 13. 6 is a flowchart for explaining a next original advance operation. The flowchart explaining the operation | movement following J of FIG. Schematic which shows the relationship between a 1st contact glass and reading position. Schematic explaining peeling of the coating of the first contact glass. Schematic which shows embodiment which half-rotates the 1st contact glass. Schematic which shows embodiment which reverses the front and back of 1st contact glass.

Explanation of symbols

5 reading part (first reading part), 54 first contact glass, 54a coating peeling part, 54b part where coating remains

Claims (3)

  An image reading apparatus that reads an image at a reading position on a coated first contact glass while conveying a document while fixing a reading unit, wherein the first contact glass is configured to be able to change the position in the front-rear direction. An image reading apparatus.   2. The image reading apparatus according to claim 1, wherein the first contact glass has coating layers on both sides thereof, and can be used by turning over the front and back of the first contact glass. The first contact glass is usually fixed to the image forming apparatus main body with a double-sided tape or the like, and a coating process is not performed on a portion to which an adhesive surface such as the double-sided tape of the first contact glass is to be applied. The image reading apparatus according to claim 1.

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