JP2007028204A - Image reading apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading apparatus effective for both sticky and floating dust and an image forming apparatus using the same.
In an image reading apparatus that reads an image at a reading position on a contact glass 43 while conveying a document while fixing a reading unit 5, when the document is set, dust is detected on the reading line. If there is dust, the contact glass 43 and the document scooping member 85 are moved in the sub-scanning direction so that there is no dust on the reading line.
[Selection] FIG.

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, and an image forming apparatus using the image reading apparatus.

2. Description of the Related Art Conventionally, as an image reading apparatus, a sheet-through method is known in which a document being transferred in the sub-scanning direction is read by a reading unit placed at a fixed position (see, for example, Patent Documents 1 and 2).
According to this sheet-through method, since the document passes while contacting the contact glass during reading, it is inevitable that dust or the like attached to the image surface side of the document adheres to the contact glass. When this deposit adheres to the reading position of the contact glass, the influence appears in the read image signal, and the image is deteriorated.
Deposits such as dust on the contact glass lead to image degradation not only in the sheet-through method but also in any method. However, in the image reading apparatus of the type in which the original is fixed and the reading unit is sub-scanned, the adhering material only appears as a black spot on the image, whereas in the case of the sheet-through type reading apparatus, the so-called extending in the sub-scanning direction. The black streak will be greatly affected.
There are two types of foreign substances: floating and sticky. Floating dust is dust, paper dust, toner, etc. Adhesive dust is glued to the contact glass on the contact glass. It is thought that the toner that is present accumulates.
In addition, floating dust such as dust may be removed by bringing the document being conveyed into strong contact with the contact glass, but the effect of removing sticky dust is weak.
In the technique described in Patent Document 1, when a document is conveyed during image reading, image reading is performed while moving the contact glass in the sub-scanning direction. Since the image reading is performed while moving the contact glass in the sub-scanning direction, dust does not stay in the reading line, so black streaks are unlikely to occur.
JP 2001-272829 A JP 2000-244703 A

With the technique described in Patent Document 1, black streaks are unlikely to occur in the finally obtained image, but there is a possibility that short black streaks or black dots will be formed. Therefore, the technique of Patent Document 1 only reduces the occurrence of black streaks and does not solve the problem.
Accordingly, an object of the present invention is to provide an image reading apparatus effective for both sticky and floating dust and an image forming apparatus using the same in consideration of the above situation.

In order to achieve the above object, according to the first aspect of the present invention, when an original is set in an image reading apparatus that reads an image at a reading position on a contact glass while fixing the reading portion and conveying the original. An image reading apparatus that moves the contact glass and the document scooping member in a sub-scanning direction in order to make dust free on the reading line when dust is detected on the reading line. And
According to the second aspect of the present invention, dust is detected on the reading line during the time from the end of image reading of a document until the next document reaches the reading position during continuous document conveyance. The image reading apparatus according to claim 1, wherein the contact glass and the document scooping member are moved in a sub-scanning direction so that there is no dust on the reading line.
Further, the invention according to claim 3 stops the movement of the contact glass and the detection of dust when the contact glass does not find a place where there is no dust at the reading position even if the contact glass makes one reciprocation by the movement. The image reading apparatus according to claim 1, wherein a display for prompting cleaning of the contact glass is performed on an operation panel.
According to a fourth aspect of the present invention, during continuous document conveyance, a document is read when it is determined that there is no dust within the time from the completion of image reading until the next document reaches the reading position. The image reading apparatus according to claim 2, wherein the image is conveyed on the operation panel on the operation panel, and the original is conveyed to the end and the contact glass is urged to be cleaned.
According to a fifth aspect of the present invention, there is provided an image forming apparatus using the image reading apparatus according to any one of the first to fourth aspects.

  According to the present invention, since a document is conveyed and read after maintaining a state where there is no dust on the reading line, it is possible to obtain a high quality image quality. Since only the contact glass is moved, there is an advantage that it is not necessary to perform ADF resist correction.

The present invention relates to an automatic document feeder (read document processing device) used in an apparatus that transports a document to be read to a fixed reader unit and reads an image while conveying the document at a predetermined speed. The basic configuration, operation, and action will be described according to the embodiment.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention relates to an automatic document feeder that is used in an apparatus that conveys a document to be read to a fixed reading device unit and reads an image while conveying the document at a predetermined speed.
FIG. 1 is a sectional view showing a basic configuration of an automatic document feeder (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 document bundle to be read, a separation feeding unit 2 for separating and feeding documents one by one from the set document bundle, and a fed document. It is composed of a resist unit 3 for temporarily abutting and aligning, a resist unit 3 for extracting and transporting the aligned document, and a turn unit 4 for turning the transported document and transporting the document surface toward the reading side (downward). The
The ADF also reads the front image of the original from the lower side of the reading glass (contact glass) 43, the first reading conveyance unit 5 for reading the back side image of the original after reading, and the reading of the front and back sides. A paper discharge unit 7 that feeds a document that has been completed to the outside of the machine 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 drives these conveying operations Each drive unit (drive source) 59 to 63 and a controller unit 58 that controls a series of operations are configured.
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. Accordingly, the shielding of the document set detection sensor 28 is released, and when the document set is detected, the document set detection sensor 28 is detected via the I / F unit 65. A document set signal is transmitted to the main body control unit 64.

Further, the length of the document in the conveyance direction is roughly determined by a document length detection sensor 12 or 14 (a reflective sensor or an actuator type sensor that can detect even one document) provided on the document table surface. Is determined (a sensor arrangement capable of determining at least whether the document size is vertical or horizontal is necessary).
Thereafter, a document feed operation is executed by a document feed signal (a signal input from an operation unit (not shown) and instructed from the main body control unit to the controller unit 58 via the I / F unit 65) (a flowchart diagram to be described later). 4 to 6).
The block diagram of FIG. 3 showing the circuit configuration of the second reading unit will be described. The light source unit 71 of the contact image sensor (second reading unit) 44 is turned on by the DF controller unit 58, and the sensor chip 72, amplifier 73, A / A signal is sent to the image processing unit 75 via the D converter 74, and this signal is sent from the I / F circuit 65 to the main body control unit 64 via the frame memory 76 and the output control circuit 77.

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.
1 to 6, it is determined whether or not a document is set (S1). If the document is set, CW (forward rotation, clockwise) drive of a drive unit (calling motor) 59 (in the embodiment, a stepping motor is used). (Although it can be realized with a solenoid), the operation starts (S2). It is determined whether or not the document stopper 21 is retracted (S3). If the document stopper 21 is retracted, the document stopper 21 is retracted to the solid line position and the leading edge of the document is opened.
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) 59 (S4) and is pressed with 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 59 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, the drive source (paper feed motor) 60 for driving the separation feeding unit 2 and the registration unit 3 rotates in the CW (forward rotation) direction (S7), and the pickup roller 20 rotates 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 59 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 59 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) 60 while being pressed against the pull-out roller 30 with a predetermined amount of bending (S16). Here, the drive unit (reading motor) 61 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) 59 in the CCW direction, the pickup roller 20 is retracted from the upper surface of the original and the original is fed only by the conveying force of the paper feed belt 23, so that the front end of the original is the pull-out roller 30. 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 36 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 60 and the reading motor 61 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) 60 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 to be higher than the reading speed.
The reading conveyance roller 39 is also driven at the same speed by a driving unit (reading motor) 61. 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 39 and the pressure roller 35, stopped at a position where a predetermined pulse has been conveyed from detection of the registration sensor 36, and a registration stop signal is transmitted to the main body control unit 64, and the main body control unit It waits for input of a reading start signal from 64 (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 61 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 39 and the pressure roller 35 which are rotated by the normal rotation driving of the driving unit (reading motor) 61.
The driving speed of the driving unit (reading motor) 61 at this time is determined based on information transmitted from the main body control unit 64 to the controller unit 58 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 reading glass 43 and the white background plate 40 disposed 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 means for reducing the conveyance gap as much 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 38 in the direction of the white background plate 40 and filling the gap is effective.
Further, the white background plate 40 is pressed with a predetermined elasticity on the reading glass 43 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 reading glass 43 is treated with a surface active agent (silicon-based activator) so that 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 43 at the reading point position, and the front end of the original wipes the vicinity of the reading point of the reading glass 43 (the front end). The action of scraping off foreign matter on the glass surface) is adopted.

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).

Referring to FIGS. 1 and 2, the timing at which the leading edge of the document reaches the reading unit 5 is controlled by the pulse count of the driving unit (reading motor) 61, and the surface image effective reading area in the sub-scanning direction is indicated at that timing. A surface DF gate signal is transmitted.
Thereafter, the document advances while being read, and is fed to the intermediate conveyance pressure roller 42 through the pickup guide 41. Since the pressure roller 37 and the intermediate conveyance pressure roller 42 are driven by the reading conveyance roller 39, 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 42 is sent to the second reading and conveying unit 6, and the contact image sensor 44 disposed with the reading unit facing downward from the upper surface and the lower side, It passes between the pressing members 45 arranged on the reading surface of the contact image sensor 44 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 44 is controlled by the conveyance pulse count from the detection of the leading edge of the registration sensor 36, and the effective reading area of the back image is determined by the contact sensor unit (contact image sensor 44 at this 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 76 shown in FIG. 3, and then transferred to the main body control unit 64. The pressing member 45 serves as a reference for shading and serves as a white background plate.
If the paper discharge sensor 60 is on, it is checked whether or not the registration sensor 36 is off (S42). If it is not off, it is determined whether or not the jam detection time is over (S43), and a resist retention jam is determined (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 63 is turned on (S55), the reading motor speed is set to the size reading speed (S56), The reading motor 61 is rotated forward (S57).
Next, it is determined whether or not the paper discharge sensor 46 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 46 is on in step (S58), the reverse motor 62 is rotated forward (S61). It is determined whether or not the paper discharge sensor 46 is off (S62). If it is not off, it is determined whether or not the jam detection time is over (S63). If the time is over, a paper discharge stay jam is detected (S64).
Next, the reverse count is started and the reading motor 61 is stopped (S65). It is determined whether the count value is equal to the predetermined pulse (S66). If equal, the reverse switching solenoid 63 is turned off, the reverse motor 62 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 61 is rotated forward (S70). Next, it is determined whether or not the reverse sensor 54 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 36 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 36 is ON in step (S74), the tip count is started (S77), and the reading motor speed is set by 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 63 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 the paper discharge sensor 46 is ON (S85).
If the paper discharge sensor 46 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 46 is on, the reverse motor 62 is rotated forward (S88).
Next, it is determined whether or not the registration sensor 36 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 36 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 or not the paper discharge sensor 46 is off (S98).
If the paper discharge sensor 46 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 46 is off, then the reverse count is started and the reading motor 61 is stopped (S101).
It is determined whether the count value is equal to the predetermined pulse (S102). If equal, the reverse switching solenoid 63 is turned off, and the reverse motor 62 is reversely rotated (S103).

Moving to FIG. 13, the reading motor 61 is rotated forward (S104), and it is determined whether or not the reverse sensor 54 is on (S105). If not, it is determined whether or not the jam detection time is over (S106). Reversal unachieved jam (S107).
Next, it is determined whether or not the registration sensor 36 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 46 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 36 is off (S114). If it is not off, it is determined whether or not the jam detection time is over (S115).
Turning to FIG. 14, it is determined whether or not the paper discharge sensor 46 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 stay jam is detected (S119). If the paper discharge sensor 46 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 39 during reading of the document image is driven by the driving unit (reading motor) 61 at a speed corresponding to the reading magnification instructed from the main body control unit 64, the conveying speed of the next original is the speed of the reading and conveying roller 39. At the same speed, it must be fed into the nip between the reading conveyance roller 39 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) 59 is rotated forward (S123).
It is determined whether the pickup roller 20 is at the calling position (S124). If the pickup roller 20 is at the calling position, the calling motor 59 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) 60 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 59 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 59 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 60 (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). CCWC rotation (reverse rotation) of the paper feed motor 60 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-sheet pulse count value, and the drive unit (feed motor) 60 is driven in reverse when the paper advances from the pull-out roller 30 by a predetermined inter-sheet interval. 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 39) by the detection of the leading end detection sensor 34, or is reduced to the reading speed (S142).
A control pulse of the drive unit (reading motor) 61 until the trailing edge of the document passes the leading edge detection sensor unit (more specifically, a motor drive pulse when the drive unit 61 is configured by a stepping motor or a brushless motor, When the drive unit 61 is composed of 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 36 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 36 is on, the registration stop pulse count starts (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 60 and the reading motor 61 are stopped. (S148), a registration stop is transmitted (S149).
As described above, the timing of ending the document reading areas on the front and back sides 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 47 and 48 including a discharge drive roller 47 and a discharge pressure roller 48. 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 reading motor 61 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 61 resumes driving when the reading starts, the paper discharge completion signal is transmitted to the main body control unit 64 when the trailing edge of the original leaves the paper discharge sensor 46, and the process is completed.

Further, the width of the document leading edge past the pull-out roller 31 is detected by the size detection sensor 32 in the direction orthogonal to the conveyance direction. When an accurate document size is determined by a combination of the width signal and the length signal obtained by the document length detection sensor 12 or 14, a document size signal is sent from the controller unit 58 to the main body control unit 64. It is transmitted via the I / F unit 65.
Thereafter, the original is sent to the nip between the reading conveyance roller 39 and the pressure roller 35, stopped at a position where a predetermined pulse is conveyed from the detection of the registration sensor 36, and a registration stop signal is transmitted to the main body control unit 64 to control the main body. It waits for the input of a reading start signal from the unit 64 (a signal transmitted when synchronization with the transfer paper or preparation for storage in the image memory is completed).
When stacking small-size documents, the reversing switching claw 50 of the reversing unit 8 is switched to a state indicated by a broken line by a driving source (reversing switching solenoid) 63, and the document is conveyed to the reversing path 55, and the reversing discharge driving roller. The paper is discharged from a pair of reverse conveying rollers 51 and 52 formed of 51 and a reverse paper discharge driven roller 52 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. In addition, the document setting table 10 is configured so as to be able to rotate upwards with the rotation fulcrum 15 as the center, thereby improving the stack document extraction performance.
Further, when the document is discharged, the operation of the reverse switching claw 50 is synchronized with the trailing edge of the discharged document, and immediately after the document is discharged, the reverse switching claw 50 is rotated in the direction of the broken line by the drive source 63 to Control is performed to strike the trailing edge and prevent the trailing edge of the discharged document from remaining. The above is an overview of the processing for single-sided or double-sided originals with the same-size original bundle. Next, processing for single-sided and double-sided originals when mixed sizes will be described.

When the sizes are mixed, since the document lengths are mixed, the document length detection sensors 12 and 14 on the document set table 10 cannot be discriminated. The size can be determined only after leaving the bundle 13 and becoming completely independent.
Therefore, when it is desired to determine the document size before reading, the document path configuration is set to ½ of the maximum document length from the first document trailing edge detection position after separation to the registration sensor 36 position before reading. It is necessary to set to the above length.
If this is satisfied, the document setting position needs to be greatly separated from the reading position, and the portion including the document setting table 10 and the conveyance path 55 becomes large, so that 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, 10, 13, and 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 64 (particularly, the discharge unit 7 and subsequent processing). Is different.
When the paper passes through the reading section and is discharged, the reverse switching claw 50 is moved in the direction of the broken line by the driving source 63 before the leading edge of the original comes out of the discharge rollers 47 and 48 (flow diagram 9). Is fed to the reverse path 55 side.
Thereafter, the original is fed by reverse paper discharge roller pairs 51 and 52 driven by a drive source (reverse motor) 62 until the rear end of the original passes through the paper discharge roller pairs 47 and 48. This control is performed based on the pulse count from the paper discharge sensor 46 (flow S66).

After the document stops, the reverse switching claw 50 is moved in the solid line direction by the drive source 63 so that the rear end of the document is directed in the nip direction of the reverse conveying rollers 51 and 52. Thereafter, the reverse paper discharge drive roller 51 rotates in the counterclockwise direction, and the document end (initial state) is placed at the nip portion of the reverse roller pair 47 and 53 composed of the stopped paper discharge drive roller 47 and the reverse upper roller 53. The leading edge skew matching operation is performed (flow S67), and then the reverse roller pair 47, 53 starts feeding by the driving source 61 and again passes through the turn section 4 to perform the first reading conveyance. Is sent to the unit 5 and the second reading and conveying unit 6 to read the front and back sides (flows S77 and S78).
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 first, and the front side is read later. First, the back side gate on signal is transmitted (flow S80), and then the front side gate signal is turned on. A signal is transmitted (flow S84). Based on this signal, the page order is changed on the image processing apparatus side.
This completes the reading operation. However, if the sheet 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. (Flows S56 and S104).
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 44 for both-side originals, this reading device is expensive, and even if a configuration without this device is used, both-side original 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 a document stacker (discharge 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 of image is read by the first reading / conveying unit 5, which is sent to the reversing unit 8, after being abutted and aligned with the pair of reversing rollers 47 and 53, again. The first reading conveyance unit 5 is sent to read the second page.
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 51 and 52 and the registration sensor 36.

FIG. 17 is a flowchart for explaining the dust detection operation. FIG. 18 is a flowchart for explaining the dust detection operation in the case of the dust presence determination. FIG. 19 is a schematic view showing a moving mechanism for moving the contact glass and the document scooping member in the sub-scanning direction. 20 is a schematic view of the moving mechanism of FIG. 19 as seen from the left side. FIG. 21 is a schematic exploded perspective view showing the moving mechanism of FIG.
As shown in FIG. 19, the moving mechanism uses a rack 84 and a pinion 80 to reciprocate the integrated contact glass 43 and document scooping member 85 in the sub-scanning direction indicated by the arrow. The movement of the contact glass 43 and the document scooping member 85 is performed by rotating the pinion 80 with a motor (not shown) using the control of the main body control unit 64 (see FIG. 2).
The contact glass 43 and the document scooping member 85 advance and retract integrally. By arranging the wiping means on the moving path of the contact glass 43 at a place where it does not interfere with the reading position, the foreign matter adhering to the upper surface of the contact glass can be removed.
The rack 84 is configured to advance and retreat within the detection range of the two sensors 81 and 82 fixed at a predetermined interval in the sub-scanning direction.
When the dust detection means determines that “dust is present”, the contact glass 43 and the document scooping member 85 are moved, and the distance is set to 1 mm, for example. When the rack 84 passes through the portion of the first sensor 81, the rotation direction of the motor (not shown) is changed as an opportunity, the direction in which the pinion 80 rotates is reversed, and the right direction in relation to FIG. The contact glass 43 is moved.
When the rack 84 is separated from the second sensor 82, the rotation direction of the pinion 80 is reversed, and the contact glass 43 and the document scooping member 85 are moved to the left in relation to FIG. Although dust detection is started when a document is set in the image reading apparatus, it may be performed when the main body is activated.

In FIG. 17, if dust adheres to the contact glass 43 (reading glass) (see FIG. 1) and there is dust on the reading line, a black streak image is formed.
Therefore, when the document is set on the image reading device (S150), it is determined whether or not the movement of the movable contact glass 43 has made one reciprocation (S151). If one reciprocation has been made, the operation panel (not shown) is displayed. The presence or absence of contamination of the contact glass 43 is displayed (S152).
If there is no reciprocation, the presence or absence of dust on the reading line is detected and determined by pre-scanning of the reading optical system or any other method (see JP-A-10-56542) (S153). If it is determined, the contact glass 43 and the document scooping member 85 (described later) are moved in the sub-scanning direction (S154). Dust detection is performed again at the moved position (S153), and when it is determined that there is no dust, image reading is started (S155).
However, when it is determined that “dust is present” again, the contact glass 43 and the document scooping member 85 are moved again in the sub-scanning direction (for example, 1 mm), dust detection is performed, and “no dust” is determined. Start image reading.
If it is determined that “dust is present”, it is moved in the sub-scanning direction (for example, 1 mm), and the contact glass 43 and the document scooping member 305 are continuously moved until “no dust” is detected (S154).
The movable contact glass 43 reciprocates, and even after one reciprocation (S151), if the detection of “with dust” continues to occur, the movement of the contact glass 43 and the dust detection are stopped, and the operation panel is placed on the operation panel. It is displayed that the contact glass 43 is dirty (S152), and the operator is prompted to clean the contact glass 43.
Then, after cleaning the dust, the dust on the contact glass 43 is detected (S153). When it is determined that “no dust”, image reading is started. It is displayed on the operation panel that the contact glass 43 is dirty (S152).

Even if dust comes on the scanning line during continuous document feeding, whether or not there is dust on the scanning line during the time from when the document is scanned until the next document comes to the scanning position. Perform dust detection.
When there is dust, the contact glass 43 and the document scooping member 85 are moved in the sub-scanning direction so that the image is read after there is no dust on the reading line, so that high-quality image quality can be obtained. Become. Since only the contact glass 43 and the document scooping member 85 are moved, it is not necessary to perform ADF registration correction.
The time when the leading edge of the next document passes the registration sensor 36 (S156) and the time when the leading edge of the next document comes before the reading position is set, and it is determined whether or not this time has passed (S157). After the image of the eye original is read by the reading unit, dust detection is performed until the leading edge of the next original comes before the reading position (S159).
If it is determined that there is no dust, the image reading is performed without moving the contact glass 43 and the document scooping member 85 (S161). In the case of the determination of “having dust”, dust detection is performed after the contact glass 43 and the document scooping member 85 are moved in the sub-scanning direction. If it is determined that there is no dust, the image is read.
If it is determined that “dust” is present, the contact glass 43 and the document scooping member 85 are moved in the sub-scanning direction (S160), and the contact glass 43 and document scooping member 85 are determined until “no dust” is determined. Is continued (S160). However, since there is time for the next document to reach the reading position, if the determination of “no dust” is not obtained within that time, scanning is not performed (S157), and the document is transported to the end. .
Then, it is displayed on the operation panel that the contact glass 43 is dirty (S158), and the operator is prompted to clean the contact glass 43. Further, the fact that there is a document that has not been scanned is displayed on the operation panel to notify the operator.
If it is not possible to find a place where there is no dust at the reading position even if the contact glass 43 and the document scooping member 85 are reciprocated once, the movement of the contact glass 43 and the document scooping member 85 and dust detection are stopped. Since it is displayed on the operation panel (not shown) that the contact glass 43 is dirty and the operator is prompted to clean the contact glass 43, an abnormal image can be eliminated.

It is sectional drawing which shows the basic composition of ADF. It is a control block diagram of ADF of FIG. FIG. 3 is a block diagram illustrating a circuit configuration of a second reading unit in FIG. 2. 6 is a flowchart illustrating execution of a document feeding operation. 5 is a flowchart illustrating execution of a document feeding operation following A in FIG. 4. 6 is a flowchart illustrating execution of a document feeding operation following B in FIG. 5. 6 is a flowchart illustrating an original reading operation by inputting a reading start signal. It is a flowchart explaining the operation | movement following C of FIG. It is a flowchart explaining the operation | movement following D of FIG. 10 is a flowchart illustrating an operation following E in FIG. 9. It is a flowchart explaining the operation | movement following F of FIG. 12 is a flowchart for explaining an operation following G in FIG. 11. 13 is a flowchart for explaining an operation following H in FIG. 12. It is a flowchart explaining the operation | movement following I of FIG. 6 is a flowchart illustrating a next original advance operation. It is a flowchart explaining the operation | movement following J of FIG. It is a flowchart explaining the operation | movement of dust detection. 10 is a flowchart for explaining an operation of dust detection in the case of determination of the presence of dust. It is the schematic which shows the moving mechanism which moves a contact glass and a document scooping member in a subscanning direction. It is the schematic seen from the left side which shows the moving mechanism of FIG. FIG. 20 is a schematic exploded perspective view showing the moving mechanism of FIG. 19.

Explanation of symbols

5 Reading unit (first reading unit)
43 Contact glass (reading glass)
80 Moving means (pinion)
81 First sensor 82 Second sensor 84 Moving means (rack)
85 Document scooping member

Claims (5)

  In an image reading apparatus that reads an image at a reading position on a contact glass while fixing a reading portion and conveying a document, when dust is detected by dust detection on a reading line with the document set, An image reading apparatus comprising: a control unit configured to control the contact glass and the document scooping member to move in the sub-scanning direction to remove dust.   The control unit performs dust detection on the reading line during the time from the end of image reading of the previous document during the continuous document conveyance until the next document reaches the reading position, and if there is dust, the contact glass 2. The image reading apparatus according to claim 1, wherein dust is removed by moving the document scooping member in the sub-scanning direction.   When the contact glass does not detect a position where there is no dust at the reading position even if the contact glass makes one reciprocation, an operation panel displays a display for stopping the movement of the contact glass and detecting the dust and prompting the cleaning of the contact glass. The image reading apparatus according to claim 1, wherein the image reading apparatus is performed as described above.   The control unit does not perform reading when it is determined that there is no dust within the time from the end of image reading of the previous document to the time when the next document reaches the reading position during continuous document conveyance. 3. The image reading apparatus according to claim 2, wherein a display for conveying the document to the end and prompting cleaning of the contact glass is performed on the operation panel.   An image forming apparatus comprising the image reading apparatus according to claim 1.

Images