JP5962339B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus and an image forming apparatus including the image reading apparatus.

  In the sheet-through type image reading device, the pickup roller is brought into contact with the upper surface of the uppermost document placed on the document tray and fed out onto the conveyance path, and then introduced into the nip of the pair of separation rollers, and further conveyed. A document image is read when transported downstream in the direction and passed over a strip-shaped reading glass provided along a direction orthogonal to the transport direction.

At this time, paper dust or the like adhering to the document may fall and adhere to the reading glass, and when the image of the next document is read in such a state, the image acquired from the document is changed. Streaky noise occurs.
Therefore, in the image reading apparatus disclosed in Patent Document 1, a cleaning member in which brushes are arranged in rows on a long rotating body is arranged in a direction orthogonal to the document conveyance direction, and the document is read glass. Each time it passes above, the cleaning member is rotated to remove paper dust adhering to the reading glass.

JP 2010-4414 A

However, the image reading apparatus of Patent Document 1 has a problem that the cleaning member is rotated each time the document passes over the reading glass, so that the brush is easily worn, and as a result, the life is shortened. .
Therefore, it is conceivable to set the cleaning frequency of the cleaning member low. However, since the amount of paper dust generated varies depending on the document feed conditions, if the cleaning frequency is set uniformly low, the amount of paper dust generated is reduced. When it increases, it may not be able to be removed.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent the cleaning member from being shortened as much as possible while suppressing the adhesion of paper dust onto the reading glass. SUMMARY OF THE INVENTION An object of the present invention is to provide an original reading apparatus capable of performing image reading and an image forming apparatus including the original reading apparatus.

In order to achieve the above object, after the document placed on the document tray is fed out on the transport path with the pickup roller in contact with the upper surface, the paper feed roller and the transport resistance member come into contact with the contact portion. Then, the manuscript that has been scanned is transported further downstream in the transport direction, and passes through a reading position on a strip-shaped reading glass provided along a direction orthogonal to the transport direction. A sheet-through type image reading apparatus that reads an image of the document by a reading unit provided on the conveyance path, and is rotatably supported around an axis parallel to a direction orthogonal to the conveyance direction. A cleaning member in which a brush that removes foreign matter on the surface of the reading glass as the rotating body rotates is provided in a row along the rotation axis direction of the rotating body, and the rotating body Rotating drive Drive means for, in response to information about the difficulty of the delivery operation, the first pressing force acting between the original and the pick-up roller, acting between the conveying resistance member and the feeding roller A condition changing means for changing a condition for changing at least one feeding condition from a reference value out of a working time during which the second pressing force and the first pressing force are applied to one original; and the condition changing means by the condition changing means In the reference state where the condition is not changed, the reading glass is cleaned with a reference cleaning ability, and more paper dust is generated from the document than in the reference state due to the change in the condition. In this case, a cleaning control means for controlling the driving means is provided so as to clean the reading glass with a cleaning ability higher than the reference cleaning ability.

Here, the cleaning control means includes a decrease in the rotation speed of the rotating body, an increase in the execution frequency of the rotating operation of the rotating body within a unit time, and an increase in the number of rotations of the rotating body in one rotating operation. It is desirable to increase the cleaning ability above the reference cleaning ability by performing at least one.
In addition, the cleaning control means, when the condition changing means has changed the condition, causes the generation of paper dust from the document to be less than the reference state, and thus the cleaning ability of the reference. It is desirable to control the driving means so as to clean the reading glass with a low cleaning ability.

The condition changing means performs the retry operation to repeat the feeding operation for the same document when a paper feeding error occurs where the document feeding operation is not normally performed, thereby applying the first pressure contact force to one document. performs the condition change as the action time to act is increased, the cleaning control means, by an increase in the working time, it is desirable that deemed to occurrence of paper dust from the original is increased.

Further, the condition changing means may be configured such that the first pressure contact force is determined from a reference value for additional retry operations after the number of repetitions of the retry operation is equal to or greater than a predetermined number N (N is an integer of 2 or more). It is desirable to change the conditions to increase.
In addition, the cleaning control means is configured so that the number of repetitions of the retry operation is 1 or more only when cleaning immediately after the image of the document conveyed after the feeding error is eliminated by the additional retry operation. It is desirable to control the reading glass to be cleaned with a cleaning ability that is greater than the cleaning ability when the ratio is less than that, and thereafter to return the cleaning ability to the standard cleaning ability.

Alternatively, the cleaning control unit may perform the retry from the cleaning immediately after an image of the conveyed document is read after the feeding error is eliminated by the additional retry operation until the current document reading job is completed. It is desirable to clean the reading glass with a cleaning ability that is greater than the cleaning ability when the number of repetitions of the operation is 1 or more and less than N.
Here, the reading unit is provided on the first surface side of the document that passes through the conveyance path, and the first reading unit that reads an image on the first surface of the document and the first surface of the document that passes through the conveyance path. A second reading unit provided on the second side for reading the second side of the document; and the cleaning member includes a first cleaning member for cleaning the reading glass in the first reading unit; A second cleaning member for cleaning the reading glass in the second reading unit, the pickup roller and the feeding roller are arranged on the first surface side of the document, and the cleaning control means When the condition change corresponds to at least one of an increase in the first pressing force, an increase in the second pressing force, and an increase in the operation time, the cleaning capability of the first cleaning member is greater than the reference cleaning capability. It is desirable to control so that it also increases.

Further, the condition changing means changes the feeding condition so as to reduce the second pressure contact force when the document is likely to be double-fed, and the cleaning control means performs the second operation by the condition changing means. When the pressure contact force of the second cleaning member is decreased, it is desirable to control the second cleaning member so that the cleaning capability of the second cleaning member is greater than the reference cleaning capability.
And a reversing introduction means for performing a reversing operation for reversing the front and back of the document and introducing it to the reading position, and the pickup roller and the feeding roller are disposed on the first surface side of the document, In the cleaning control unit, when the reversing operation is performed, the change in the feeding condition corresponds to at least one of an increase in the first press contact force, an increase in the second press contact force, and an increase in the operation time. In this case, after the first side of the original is read for the first time, the cleaning ability of the cleaning member increases from the reference cleaning ability until the second side of the original starts to be read next time. It is desirable to control so that it does.

Here, the condition changing means, the document is, when there is a possibility that double feeding occurs, a condition feeding to reduce the second pressing force change, the cleaning control means is pre-Symbol condition changing means After the second pressure contact force is reduced, the cleaning ability of the cleaning member is between the first reading of the second document and the start of reading the first surface of the next document. It is desirable to control so that it may increase rather than the cleaning capability.

In addition, it is preferable that an acquisition unit that acquires the paper type of the document is provided, and the cleaning control unit specifies the difficulty of the feeding operation based on the acquired paper type.
Furthermore, it is preferable that the paper type is a thickness of the original, and the acquisition unit includes a thickness detection unit that detects the thickness of the original.
Alternatively, the acquisition unit may be an operation panel.

Further, it comprises a wear degree index value acquisition means for acquiring a wear degree index value indicating the wear degree of the pickup roller and the feeding roller, and the cleaning control means, when the wear degree index value is a predetermined value or more, It is desirable that the control to increase the cleaning ability with the change of the condition is prohibited to maintain the reference cleaning ability.
Here, the reading position may be within a range in which the paper dust generated in the separating portion is directly scattered and dropped.

  The present invention may be an image forming apparatus provided with the document reading apparatus.

  In the document reading apparatus according to the present invention, when the condition is changed by the condition changing unit and the generation of paper dust is larger than the reference state, the reading glass is cleaned with a cleaning ability higher than the reference cleaning ability. Therefore, the adhesion of paper dust on the reading glass is suppressed, and usually, cleaning is performed with a standard cleaning ability that is smaller than this, so it is assumed that there is a lot of paper dust from the beginning. Since the load applied to the brush is reduced and wear is less likely to occur than in the conventional case where the cleaning ability is set to be large, the life of the cleaning member can be extended.

1 is a schematic diagram illustrating a configuration of an image forming apparatus including a document reading apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the cleaning member provided in the original conveyance part of the said original reading apparatus. (A)-(d) is an operation | movement figure which shows rotation operation | movement of a cleaning member. It is a fragmentary sectional view which shows the structure of the pick-up roller and registration roller pair of the said document conveyance part. FIG. 2 is a block diagram showing a document conveyance control unit of the document conveyance unit and a control target thereof. 5 is a flowchart showing an execution procedure of a document transport process executed in the document transport control unit. 6 is a flowchart showing an execution procedure of a reading surface cleaning / reading process executed as a subroutine of the document conveying process. (A)-(c) is a figure explaining the content of the cleaning mode determined according to the manipulating condition of a document. (A)-(c) is a figure explaining the content of the cleaning mode in a double-sided simultaneous reading system. FIG. 6 is a schematic diagram illustrating a configuration of a document reading device according to a second embodiment. (A)-(c) is a figure explaining the content of the cleaning mode in 2nd Embodiment. 10 is a flowchart illustrating an execution procedure of a document transport process executed by a document transport control unit according to a third embodiment. 6 is a flowchart showing an execution procedure of document conveyance processing executed as a subroutine of the document conveyance processing. It is a figure explaining the content of the capability enhancement mode in 3rd Embodiment. (A) And (b) is a figure explaining the content of the capability enhancement mode which concerns on a modification. (A) And (b) is a figure explaining the content of the capability enhancement mode which concerns on a modification. (A) and (b) respectively show the relationship between the integrated value of the number of feedings and the friction coefficient of the outer peripheral surface of the big up roller, and the relationship between the friction coefficient of the outer peripheral surface of the big up roller and the amount of generated paper dust. FIG. (A) And (b) is a figure which respectively shows the relationship between the integrated value of the frequency | count of delivery, and the outer diameter of a Bickup roller, and the relationship between the outer diameter of a Bickup roller, and delivery pressure contact force.

(1) First Embodiment Hereinafter, an embodiment of an image forming apparatus including a document reading apparatus according to a first embodiment of the present invention is referred to as an electrophotographic color copying machine (hereinafter simply referred to as “copier”). The case of applying to the above will be described as an example.
(1-1) Configuration of Image Forming Apparatus FIG. 1 is a schematic diagram for explaining the configuration of the copying machine 1.

As shown in FIG. 1, the copying machine 1 is roughly composed of an image reading unit 2 that reads a document image and a printer unit 3 that prints the read image on a recording sheet.
(1-1-1) Printer Unit The printer unit 3 includes an image forming unit 10, a paper feeding unit 20, a fixing unit 30, a control unit 6, and the like.

The paper feed unit 20 includes a storage tray 21, a feed roller 22, a separating roller pair 23, a timing roller pair 24, and the like.
The storage tray 21 stores recording sheets.
The feeding roller 22 contacts the uppermost recording sheet of the storage tray 21 and feeds it to the recording sheet conveyance path.

One pair of the rolling rollers 23 is a driving roller and the other is a driven roller, which are in contact with each other to form a rolling nip. A torque limiter is attached to the driven roller, and the conveying direction with respect to the recording sheet Gives the opposite force.
As a result, if there is a recording sheet that has been transported, it cannot be conveyed any further, and the recording sheet is rolled up and separated into one sheet.

The timing roller pair 24 feeds the recording sheet downstream at the timing instructed by the control unit 6.
As shown in the figure, the image forming unit 10 includes image forming units 11Y, 11M, 11C, and 11K corresponding to the colors Y, M, C, and K, and the photosensitive drums 12 of these image forming units. Opposing primary transfer roller 14, intermediate transfer belt 13, secondary transfer roller 15 and the like are provided.

As shown in the figure, the image forming units 11Y, 11M, 11C, and 11K are arranged in a predetermined order in the order of 11Y, 11M, 11C, and 11K along the intermediate transfer belt 13 while facing the intermediate transfer belt 13. They are arranged in series at intervals.
For example, the image forming unit 11 </ b> K includes a photosensitive drum 12, and a charger 16, an exposure unit 17, a developing device 18, and a cleaner 19 disposed around the photosensitive drum 12.

Since the image forming units 11Y, 11M, and 11C have the same configuration as the image forming unit 11K, description thereof is omitted here.
The exposure unit 17 includes a plurality of light emitting elements such as laser diodes arranged in the main scanning direction. The exposure unit 17 applies image data acquired from the outside via a LAN or the like or document data read by the image reading unit 2. A drive signal generated by the control unit 6 is acquired, and a laser beam for exposing the photosensitive drum 12 is emitted, and the photosensitive drum 12 is exposed and scanned.

The photosensitive drum 12 is uniformly charged by the charger 16 after the toner remaining on the surface is removed by each cleaner 19 before being subjected to the exposure, and after being discharged by irradiating an eraser lamp (not shown). When exposed to the laser beam in such a uniformly charged state, an electrostatic latent image is formed on the surface of the photosensitive drum 12.
Each electrostatic latent image is developed by the developing device 18 of each color, whereby a toner image as a developer image of Y, M, C, and K is formed on the surface of the photosensitive drum 12.

The image forming operation for each color is executed at different timings so that the toner image is superimposed and transferred to the same position on the intermediate transfer belt 13, and receives the electrostatic force from the primary transfer roller 14 and receives the electrostatic force on the intermediate transfer belt 13. And a full color toner image is formed.
The superimposed toner images on the intermediate transfer belt 13 are moved to the secondary transfer position by the rotation of the intermediate transfer belt 13.

  On the other hand, in accordance with the movement timing of the intermediate transfer belt 13, the recording sheet is fed from the paper feeding unit 20 via the timing roller pair 24, and the recording sheet and the intermediate transfer belt 13 are in contact with each other. At the next transfer position, the toner image on the intermediate transfer belt 13 is secondarily transferred onto the recording sheet by the electrostatic force generated by the voltage applied to the secondary transfer roller 15.

The recording sheet that has passed the secondary transfer position is conveyed to the fixing unit 30 where the toner image is heated and pressed to be fixed on the recording sheet, and then is transferred to the discharge tray 32 via a pair of discharge rollers 31. The paper is ejected.
The control unit 6 comprehensively controls the printer unit 3 and the image reading unit 2 of the copying machine 1.
The printer unit 3 includes a numeric keypad and a touch panel, and is provided with an operation panel 7 that receives instructions from the operator and displays information to the operator.

Next, the image reading unit 2 will be described.
The image reading unit 2 is configured to be able to read a document image by both a sheet-through method that is one of fixed optical systems and a scanner moving method that is a moving optical system.
Here, the sheet-through method is a method of reading while moving the document while the optical system (reading position) is stationary (fixed).

In the scanner movement method, the optical path from the original reading position to the CCD line sensor is moved with respect to the original by moving a mirror that guides reflected light from the original surface to the CCD line sensor while the original is placed on the reading glass. This is a method of reading in a state where the length is always kept constant.
The image reading unit 2 includes a document conveying unit 5 for realizing the sheet-through method and an image reader unit 4 for reading an image.

The image reader unit 4 executes image reading by both the sheet-through method and the scanner movement method.
(1-1-2) Image Reader Unit When the image reader unit 4 reads a document by the sheet through method, the scanner 42 is located at a position (sheet through position) below the reading glass 41 for sheet through.

Then, the document passing through the upper surface of the reading glass 41 is irradiated by the lamp 44 of the scanner 42 that is stationary at the sheet through position.
The reflected light from the document surface is changed in optical path by the first mirror 43, the second mirror 45 and the third mirror 46, and is imaged on the light receiving surface of the CCD line sensor 48 by the condenser lens 47.

On the other hand, when reading a document by the scanner movement method, the document transport unit 5 is opened upward, and the document is set on the reading glass 49 for manual placement of the image reader unit 4. In this case, the scanner 42 is moved rightward in FIG.
At this time, the second mirror 45 and the third mirror 46 are paired and move in the same direction as the scanner 42 and at half the moving speed thereof. The distance (optical path length) to the optical lens 47 is always kept constant, and the reflected light of the original is imaged on the light receiving surface of the CCD line sensor 48.

The scanner 42, the second mirror 45, and the third mirror 46 are driven to travel through a power transmission mechanism (not shown) using a scan motor (not shown) as a power source.
(1-1-3) Document Conveying Unit The document conveying unit 5 is a so-called simultaneous reading type document conveying apparatus capable of reading images on both sides of a document at once by one conveyance, and includes an original document feeding tray 50. Are separated one by one from the bundle of originals set on the paper, corrected for skew, passed through the vicinity of the surfaces of the reading glass 41 and the reading glass 61a, and then discharged to the document discharge tray 51. A document conveyance control unit 200 that controls the document conveyance operation is provided.

The document bundle placed on the document feed tray 50 is lifted by the lift plate 52 by a cam mechanism (not shown) so that the leading end is lifted so that the pickup roller 53 comes into contact with the upper surface of the uppermost document. In this state, the pickup roller 53 is rotated to be fed out from the document feed tray 50 into the conveyance path 54.
Then, the original is passed through a separation nip of a roller pair 55 in which a rotationally driven roller and a roller equipped with a torque limiter are in pressure contact with each other, so that the original is wound on only one sheet, and then a registration roller pair. It is conveyed to 57.

In the present embodiment, in order to improve the document feeding accuracy, the pressure contact force between the pickup roller 53 and the document (hereinafter referred to as “feeding pressure contact force”) and the pressure contact force at the separation nip of the separating roller pair 55 (hereinafter referred to as “ "Separation pressure contact force")) can be changed. This configuration will be described later.
It should be noted that the document is placed immediately downstream of the pair of roller 55 in the document transport direction (hereinafter, upstream and downstream in the document transport direction are simply referred to as “upstream” and “downstream”, respectively). A document detection sensor 56 for detection is provided.

The registration roller pair 57 is stopped when the leading edge of the document arrives, and a loop is formed on the document upstream of the nip portion of the registration roller pair 57 to correct the inclination of the leading edge, and then a predetermined value is obtained. The skew correction is performed by rotating the document at the timing and sending out the document.
Then, the skew-corrected document is conveyed to a conveyance roller pair 58 disposed on the downstream side thereof.

The conveyance roller pair 58 is disposed on the upstream side of the reading glass 41.
The document sent out from the registration roller pair 57 passes through the conveyance roller pair 58 and is sent out so as to pass above the reading glass 41 at a predetermined timing.
As a result, the surface of the document is read by the image reader unit 4.
Then, the document that has passed on the reading glass 41 passes through the conveyance roller pair 60a and passes under the document back side reading unit 61 located ahead.

The document back side reading unit 61 has a CCD array sensor (not shown) extending in the main scanning direction of the document, and if an instruction to read the back side of the document is received from the operator via the operation panel 7. Then, the image on the back side of the document passing below is read.
Then, the document that has passed through the document back surface reading unit 61 is discharged onto the document discharge tray 51 by the pair of document discharge rollers 63 located ahead of the pair of conveyance rollers 60b.

The document conveying section 5 in the present embodiment is a cleaning extending in the main scanning direction at positions facing the outer surface of the reading glass 41 and the outer surface of the reading glass 61a of the document back surface reading section 61 across the document conveying path. A member 59 and a cleaning member 62 are provided.
(1-1-4) Cleaning Member The cleaning members 59 and 62 are for cleaning the surface of the reading glass 41 while the document is conveyed.

FIG. 2 is a perspective view of the cleaning member 59, and also shows a first cleaning member driving unit 190 that rotationally drives the cleaning member 59.
The cleaning member 59 has a semicircular cross section, and a main body portion 590 extending in a direction orthogonal to the document conveyance direction, and a flat fiber 591a of the main body portion 590 includes bundle-like fibers along the orthogonal direction. It comprises a brush portion 592 that is implanted in a plurality of bundles.

The main body 590 has rotating shafts 591b and 591c at both ends thereof, and is rotatably supported by a frame (not shown) on the main body side of the document conveying section 5.
The rotating shaft 591c is connected to the first cleaning member driving unit 190.
The first cleaning member driving unit 190 is a motor capable of controlling the rotation angle, such as a stepping motor or a servo motor.

FIG. 3 is a diagram illustrating a cleaning operation of the reading glass 41 by the cleaning member 59.
In the initial state, the cleaning member 59 is in the state shown in FIG.
The cylindrical side surface 591d of the main end 590 is white and serves as a white reference plate during shading correction.
The cleaning member 59 is driven to rotate counterclockwise in the figure by the first cleaning member driving unit 190 in accordance with the instruction of the document conveyance control unit 200, and the surface of the reading glass 41 is rubbed with the tip of the brush unit 592. Dust such as paper dust is swept out (FIG. 3B), and then returned to the original position and stopped (FIG. 3C).

In FIG. 3C, the document G passes below the cleaning member 59. At this time, the cleaning member 59 is such that the distance between the reading glass 41 and the document surface is within a predetermined range D1. It also has the function of a guide that regulates.
Further, as shown in FIG. 3D, the cleaning member 59 is driven to rotate backward at a predetermined timing in accordance with an instruction from the document conveyance control unit 200.

This is performed in order to correct the deformation of the brush portion 592 that occurs during normal rotation driving shown in FIGS. 3A to 3C to the original shape.
The cleaning member 62 has the same configuration as the cleaning member 59, and the second cleaning member drive unit 191 that rotates and drives the cleaning member 62 has the same configuration as the first cleaning member drive unit 190. Description is omitted.

(1-1-5) Configuration of Pickup Roller and Rolling Roller Pair FIGS. 4A to 4C are partial cross-sectional views showing the configuration of the pickup roller 53 and the rolling roller pair 55 and also serve as operation diagrams. .
As described above, the document conveying unit 5 according to the present embodiment has a configuration in which the feeding pressure contact force and the separation pressure contact force can be changed. This configuration will be described below.

As shown in FIG. 4 (a), the roller pair 55 is configured such that the feed roller 55a that is rotationally driven by the feed roller driving unit 180 (see FIG. 5) and the roller 55b to which a torque limiter is attached are pressed against each other. Do it.
The rotation of the feeding roller 55a is also transmitted to the pickup roller 53 via a power transmission mechanism such as a drive belt (not shown), whereby the pickup roller 53 is interlocked with the feeding roller 55a so that they are the same. Driven at peripheral speed.

The pickup roller 53 is pivotally supported by a support member 153 that is swingably provided around the drive shaft 180a of the feed roller 55a, whereby the pickup roller 53 is swingable up and down.
The support member 153 is provided with a long hole 154a. The pin 154a protruding from the main body side (not shown) of the document conveying section 5 is inserted into the long hole 154a, so that the support member 153 swings. The range is limited.

Further, the winding spring 155 urges the support member 153 in the direction of the arrow B, thereby causing the pickup roller 53 to move to the lowest position in the swing range.
Therefore, as the pickup roller 53 is pushed up against the upper surface of the document bundle and is moved upward from the lowest position, the feeding pressure contact force is increased.
A position detection unit 156 is provided above the support member 153.

The position detection unit 156 is, for example, a limit switch, and has a rod 156a that can be moved forward and backward. The projection amount of the rod 156a corresponds to each state as the protruding amount of the rod 156a becomes gradually shorter than L1, L2, and L3. A signal is output to the document conveyance control unit 200.
As a result, the document conveyance control unit 200 can detect which position the pickup roller 53 is in among the positions shown in FIGS. 4A, 4 </ b> B, and 4 </ b> C. .

Of the bottom plate of the document tray, a part on the pickup roller 53 side is a lifting plate 52 that is pivotably supported by a support shaft 52b in the vertical direction. It is in contact.
Therefore, by rotating the cam 52a with a drive motor (not shown), the elevating plate 52 swings up and down, and the distance between the upper surface of the document bundle G and the pickup roller 53 can be changed.

  When the lifting plate 52 is raised from the state of FIG. 4A, the upper surface of the original bundle G comes into contact with the pickup roller 53 and when the lifting plate 52 is further lifted, the pickup roller 53 is pushed upward. Therefore, based on the detection output from the position detection unit 156, it can be stopped at the position of FIG. 4B or FIG. 4C, and the feeding pressure contact force can be changed.

Here, it is assumed that the document conveyance control unit 200 has moved the pickup roller 53 to the position shown in FIG. 4B in order to set the feeding pressure contact force to the reference F2.
The document G is pressed from the pickup roller 53 by the reaction force of the feeding pressure contact force F2. When the document G is fed in this state, the position of the pickup roller 53 is lowered by the thickness of the document G, and the feeding pressure contact force. However, the document conveyance control unit 200 maintains the protruding amount L2 of the rod 156a of the position detection unit 156 so that the feeding pressure contact force does not change in preparation for feeding the next document G. 52 is raised.

Further, in order to set the feeding pressure contact force to F3 larger than F2, the pickup roller 53 is moved to the position shown in FIG. 4C, that is, the protrusion amount of the rod 156a of the position detection unit 156 is set to L3 (<L2). That's fine.
Thus, by adjusting the vertical position of the pickup roller 53, the feeding pressure contact force can be set to a predetermined value.

On the other hand, in the roller pair 55, the position of the feeding roller 55a is fixed, and the separation pressure contact force can be changed by swinging the roller 55b up and down.
Hereinafter, a configuration for swinging the rolling roller 55b will be described.
As shown in FIG. 4A, the roller 55b is held via a torque limiter (not shown) by a support member 158 that is swingable about a support shaft 159.

In addition, a disc-shaped rotating member 160 having a helical gear 160a formed in about half of the entire circumference is held by a support member 158 so as to be rotatable around a support shaft 159.
Then, as shown in FIG. 4A, one end of the winding spring 161 is fixed to the support member 158 and the other end is fixed to the rotating member 160.
A rotating member driving unit 162 is provided on the main body side (not shown) of the document conveying unit 5.

The rotation member driving unit 162 is a motor capable of controlling the rotation angle, such as a stepping motor. A screw gear 162 a is formed at the tip of the rotation shaft, and the screw gear 162 a is a screw of the rotation member 160. It meshes with the tooth gear 160a.
A servo motor or the like may be used instead of the above stepping motor.
When the rotating member 160 is in the position shown in FIG. 4A (hereinafter, referred to as “home position”), the winding spring 161 is set so as to urge in the direction in which the roller 55b is pushed up (arrow C direction). ing.

Further, as shown in FIG. 4C, when the rotating member 160 rotates counterclockwise in the figure, the urging force of the winding spring 161 is increased.
With the above configuration, the document conveyance control unit 200 can output a predetermined number of drive pulses to the rotating member driving unit 162 and change the angle of the rotating member 160 to set the separation pressure contact force to a target value. it can.

The change of the feeding pressure contact force and the separation pressure contact force by the document conveyance control unit 200 is performed according to the thickness of the document G.
For example, when comparing plain paper, thick paper, and thin paper, since the thick paper has a large mass, a frictional force between the thick paper and the original G underneath acts so that a so-called paper feed error that causes unsuccessful feeding tends to occur.

Here, thin paper, plain paper, and thick paper are distinguished as follows according to the weight per unit area, that is, the basis weight.
That is, the basis weights of thin paper, plain paper, and thick paper are generally 30 [g / m2] to 50 [g / m2], 60 [g / m2] to 80 [g / m2] and 126 [g, respectively. / M2] or more, and the definitions of thin paper, plain paper, and thick paper in the present embodiment also conform to this.

Therefore, when feeding a thick paper document, the document conveyance control unit 200 increases the feeding pressure contact force and the separation pressure contact force from the reference values.
Thereby, the frictional force with respect to the original G of the pickup roller 53 and the feeding roller 55a is increased, the force for conveying the original G can be increased, and the occurrence of a paper feed error can be suppressed.

The reference values of the feeding pressure contact force and the separation pressure contact force are obtained in advance through experiments or the like as values when a plain paper document is properly conveyed.
On the other hand, when the thin paper original G is fed out, the mass is small, so that not only the uppermost original G but also the original G below it is fed out, so-called double feeding is likely to occur.
Therefore, when feeding the thin paper document G, the document conveyance control unit 200 keeps the feeding pressure contact force at the reference value and makes the separation pressure contact force smaller than the reference value.

As a result, the frictional force between the feeding roller 55a and the separating roller 55b is reduced, so that the followability of the separating roller 55b to which the torque of the torque limiter is applied to the feeding roller 55a is reduced, and the separating roller 55b is dispersed. The peripheral speed at the nip becomes slower than the peripheral speed of the feeding roller 55a, or the rotation is stopped.
Therefore, even if double feeding occurs at the pickup roller 53, the frictional force generated between the multi-fed originals is reduced by the amount that the pressure contact force at the separation nip is reduced, and the accompanying force is weakened. It is possible to increase the conveyance resistance with respect to the original, and to more reliably prevent double feeding at the separation nip.

In this embodiment, the user inputs through the operation panel 7 whether the original G placed on the original tray is plain paper, thin paper, or thick paper, and the original conveyance control. The unit 200 changes the feeding pressure contact force and the separation pressure contact force based on this input information.
The most frequently used plain paper is set as a default, and when there is no input from the user regarding the thickness of the original, the feeding pressure contact force and the separation pressure contact force corresponding to the plain paper are set. .

(1-2) Relationship between Feeding Pressure and Separation Pressure and Amount of Paper Dust Generated By the way, generally, when a rotating roller contacts the original G with a high frictional force, the paper dust from the original G The amount of generation increases.
For example, when the feeding pressure contact force and the separation pressure contact force are increased, the original G is strongly rubbed by the pickup roller 53 and the feeding roller 55a, and is exaggerated by d1 and d2 in FIGS. 4B and 4C. In addition, the amount of paper dust generated from the upper surface side of the original G is increased more than usual.

If the separation pressure contact force is reduced, the original G that has not been double-fed is rubbed with the original G and the roller 55b, and the paper from the lower side of the original G is shown in FIG. It is thought that the generation amount of powder increases more than usual.
Therefore, it is considered that the document conveyance control unit 200 according to the present embodiment first sets the normal cleaning frequency in the cleaning member 59 and the cleaning member 62 to be lower than that in the past, and the amount of paper dust generated is higher than normal. In this case, the cleaning frequency is controlled to be increased.

In addition, when the amount of paper dust generated is considered to be lower than usual, the cleaning frequency is controlled to be further reduced.
Here, the normal state refers to a state (hereinafter referred to as “reference state”) in which a feeding operation is performed with a feeding pressure contact force and a separation pressing force corresponding to the plain paper when the plain paper is fed out. means.

(1-3) Document Conveyance Control Unit FIG. 5 is a block diagram showing the document conveyance control unit 200 and its control target. In FIG. 5, the relationship between the printer unit 3 and the image reader unit 4 is also shown. Has been.
The conveyance operation of the document placed on the document feed tray 50 is controlled by the document conveyance control unit 200.

The document conveyance control unit 200 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, a nonvolatile memory 204, a timer 205, and the like.
The ROM 202 stores a control program for executing a document conveying operation.

A RAM 203 is a volatile memory and serves as a work area when the CPU 201 executes a program.
The non-volatile memory 204 is, for example, an EEPROM (registered trademark), and serves as a data storage area of the CPU 201.
The timer 205 counts up by counting up every predetermined time in accordance with an instruction from the CPU 201.

The CPU 201 executes a document transport process (hereinafter referred to as “document transport process”) by executing a control program stored in the ROM 202.
This document conveying operation includes a process of changing the cleaning frequency of the cleaning member 59 and the cleaning member 62.
(1-4) Contents of Document Conveying Process Hereinafter, the document conveying process in the document conveying control unit 200 according to the first embodiment will be described with reference to the flowchart of FIG.

  When the main power is turned on, the document conveyance control unit 200 waits until an instruction to read a document is received from the user via the operation panel 7 (step S11: NO), and when the instruction to read the document is received (step S11: NO). Step S11: YES), information on the thickness of the document, that is, information indicating whether it is plain paper, thick paper, or thin paper is acquired via the operation panel 7 (Step S12).

Then, it is determined whether or not the original is thin paper. If it is not thin paper (step S13: NO), it is determined whether or not it is next thick paper (step S14: NO). Since it is determined that the original is plain paper, the value of the feeding pressure contact force is set to a reference value F _P 1 suitable for feeding plain paper, and the separation pressure contact force is suitable for spreading plain paper. The reference value F _D 1 is set (step S15).

Next, the value of the flag F indicating the type of document stored in the nonvolatile memory 204 is set to “1” indicating plain paper (step S16).
If the original is thick paper (step S14: YES), the feeding pressure contact force and the separation pressure contact force are values F _P 2 and F larger than their respective reference values in order to suppress the occurrence of a paper feed error. _D 2 is set (step S18), and the value of the flag F is set to “2” indicating that the paper is thick (step S19).

If the original is thin (step S13: YES), the value of the feeding pressure contact force is set to the reference value F _P 1 and separation is performed so that double feeding does not occur downstream of the registration roller pair 57. The pressing force is set to F _D 3 smaller than the reference value F _D 1 (step S20), and the value of the flag F is set to “3” indicating that the sheet is thin (step S21).
After setting the flag F, it is determined whether or not the document transport timing has arrived (step S17).

Here, the document conveyance control unit 200 obtains the length of the document by a known document size sensor (not shown), and the pickup roller 53, the feeding roller 55a, and the document so that the space between the documents is a predetermined interval. Since the drive timing of the rollers such as the registration roller pair 57 is determined by itself, it is possible to determine the document transport timing.
When the document conveyance control unit 200 determines that the document conveyance timing has come (step S17: YES), the document conveyance control unit 200 starts the document conveyance operation by rotating the pickup roller 53, the feeding roller 55a, and the like (step S22).

This document transport operation includes driving of all the rollers positioned downstream of the feeding roller 55a, and the document transport control unit 200 at the time of driving the registration roller driving unit 181 including a servo motor or the like. The conveyance roller driving unit 182 and the discharge roller driving unit 183 are controlled to be turned on and off.
Then, the document conveyance control unit 200 stands by until the cleaning timing comes (step S23: NO), and when the document is sent out from the registration roller pair 57 and the cleaning timing comes (step S23: YES). In response to an instruction from the user, a subroutine process (hereinafter referred to as “reading surface cleaning / reading process”) is performed in which the reading glass 41 or both of the reading glasses 41 and 61a are cleaned to read an image of a document. (Step S24) If the read original is the last of a series of originals for which an instruction for reading has been received (Step S25: YES), the original conveying process is terminated.

If it is not the last document (step S25: NO), the processes after step S17 are repeatedly executed.
Note that the document conveyance control unit 200 starts timing by the timer 205 from the start of the rotation of the registration roller pair 57, and when the measured time reaches a predetermined time, the timing for cleaning has come. judge.

Here, the predetermined time is set so that the cleaning is completed before the leading edge of the document is introduced onto the reading glass 41.
(1-4-1) Contents of Reading Surface Cleaning / Reading Processing Hereinafter, reading surface cleaning / reading processing executed as subroutine processing in the document conveyance processing will be described with reference to the flowchart of FIG.

  When the instruction to read both sides of the document is not received, that is, when only the front side is read (step S101: NO), the document conveyance control unit 200 determines the value of the flag F (step S102), and the value Is “1”, that is, indicates plain paper (step S102: YES), the reading surface cleaning / reading process is executed in the following standard mode (step S103), and the process returns to the main routine.

FIG. 8A illustrates the reading surface cleaning / reading process in the standard mode.
In the figure, time flows from left to right, and an upward arrow means that the cleaning member 59 is rotated once by forward rotation (hereinafter referred to as “+1 rotation”), and the downward direction The arrow means that the cleaning member 59 is rotated once by reverse rotation driving (hereinafter referred to as “−1 rotation”).

As shown in the figure, the cleaning member 59 is rotated by +1 immediately before the first original passes over the reading glass 41, and thereafter, every time two originals pass, the cleaning member 59 is moved between the sheets. Repeat the operation of +1 rotation.
Then, only when the last document passes over the reading glass 41, after the last document passes, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592.

As described above, in the standard mode, the cleaning member 59 may not be rotated between the sheets, and accordingly, the wear of the brush portion 592 of the cleaning member 59 is more than that in the conventional case where the cleaning member is rotated between the sheets. It is reduced. In the case of plain paper, paper dust generated with such a cleaning frequency can be sufficiently removed.
Returning to FIG. 7, if the value of the flag F is not “1” (step S102: NO), it is determined whether or not the value of the flag F is “2”, and the value is “2”. If it indicates thick paper (step S104: YES), the feeding pressure contact force and the separation pressure contact force are made larger than the reference values in step S18, so that the generation of paper dust from the surface of the document increases. Since it is expected, the reading surface cleaning / reading is executed in a mode (hereinafter referred to as “ability enhancing mode”) in which the cleaning ability is enhanced as described below (step S105), and the process returns to the main routine.

FIG. 8B is a diagram for explaining the reading surface cleaning / reading process in the capability enhancement mode, and how to read the drawing is the same as FIG. 8A.
A black arrow indicates that a cleaning operation is newly added to the standard mode.
As shown in FIG. 8B, the cleaning member 59 is rotated by +1 immediately before the first original passes over the reading glass 41, and thereafter, every time one original passes, cleaning is performed between sheets. The operation of rotating the member 59 by +1 is repeated.

Then, only when the document has finally passed over the reading glass 41, after the last document has passed, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592.
As described above, in the capacity enhancement mode, the cleaning member 59 is rotated by +1 rotation between the sheets, so that the reading glass 41 is thoroughly cleaned to prevent deterioration in image reading quality such as streak noise in the image. Can do.

Returning to FIG. 7, if the value of the flag F is not “2” (step S104: NO), the value of the flag F is “3”, that is, indicates thin paper. Is smaller than the reference value, the generation of paper dust from the front surface of the original document is reduced, but the generation of paper dust from the back surface is expected to increase.
Here, only the front surface of the document is read, and the paper dust generated from the back surface hardly affects the reading quality. Therefore, it is only necessary to consider that the paper dust on the front side of the document is reduced.

Therefore, the document conveyance control unit 200 executes the reading surface cleaning / reading process in a mode in which the cleaning capability is suppressed as described below (hereinafter referred to as “capability suppression mode”) (step S106). Return to routine.
FIG. 8C is a diagram for explaining the reading surface cleaning / reading process in the capability suppression mode, and the way of viewing the drawing is the same as that in FIG.

In addition, the arrow of a broken line shows that the cleaning currently performed in standard mode is abbreviate | omitted.
As shown in FIG. 8C, the cleaning member 59 is rotated by +1 immediately before the first original passes over the reading glass 41. Thereafter, every time three originals pass, cleaning is performed between sheets. The operation of rotating the member 59 by +1 is repeated.

Then, only when the document has finally passed over the reading glass 41, after the last document has passed, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592.
As described above, in the capability suppression mode, the cleaning member 59 is rotated by +1 rotation between sheets every time three documents pass, so that the cleaning frequency is less than in the standard mode, and the brush portion 592 of the cleaning member 59 is worn. It is reduced more.

Even if the cleaning frequency is reduced in this way, as described above, the amount of paper dust generated is reduced, so that no problem occurs.
Returning to FIG. 7, when the instruction to read the images on both sides of the document is accepted (step S101: YES), the value of the flag F is determined, and the value is “1”, that is, indicates plain paper. If yes (step S107: YES), the reading surface cleaning / reading process is executed in the following double-sided standard mode (step S108), and the process returns to the main routine.

FIG. 9A is a diagram for explaining the reading surface cleaning / reading process in the double-sided standard mode, and the way of viewing the drawing is the same as FIG. 8A.
The hatched arrow in the lower row indicates the cleaning operation of the cleaning member 62 at the back surface reading position.
As shown in the figure, the cleaning members 59 and 62 are rotated by +1 each immediately before the first original passes over the reading glasses 41 and 61a, and thereafter two originals are placed on the reading glasses 41 and 61a. Every time it passes, the operation of rotating the cleaning members 59 and 62 by +1 between the sheets is repeated.

Then, only when the last document has passed over the reading glasses 41 and 61a, after the last document has passed, the cleaning members 59 and 62 are rotated by -1 respectively to provide the brushes provided on the cleaning members 59 and 62. The deformation of the portion 592 is corrected.
As described above, in the standard mode, the cleaning members 59 and 62 may not be rotated between sheets, and accordingly, the wear of the brush portion 592 of the cleaning members 59 and 62 causes the cleaning member to rotate between sheets. It is reduced compared to the conventional one.

  Returning to FIG. 7, if the value of the flag F is not “1” (step S107: NO), it is determined whether or not the value of the flag F is “2”, and the value is “2”. If it indicates thick paper (step S109: YES), the feeding pressure contact force and the separation pressure contact force are raised from the reference values in step S18, so that it is expected that the generation of paper dust from the surface of the document increases. Therefore, the reading surface cleaning / reading process is executed in the following double-sided capability enhancement mode (step S110), and the process returns to the main routine.

FIG. 9B is a diagram for explaining the reading surface cleaning / reading process in the double-sided capacity enhancement mode, and the way of viewing the drawing is the same as FIG. 9A.
As shown in FIG. 9B, the cleaning members 59 and 62 are rotated by +1, respectively, immediately before the first original passes over the reading glasses 41 and 61a.
Thereafter, each time one document passes over the reading glass 41, the cleaning member 59 is rotated by +1 between the sheets, and every time two documents pass over the reading glass 61a, the cleaning member is moved between the sheets. The operation of rotating 62 by +1 is repeated.

That is, the cleaning capability of the cleaning member 59 that cleans the reading glass 41 facing the front side of the document is increased, but the cleaning capability of the cleaning member 62 that cleans the reading glass 61a facing the back side of the document is not changed.
This is because when the feeding pressure and the separation pressure are increased from the reference values, the frictional force applied to the surface of the original increases and the generation of paper dust at that portion increases. Although the adhesion of paper dust to the paper 41 increases, the increase in both pressing forces does not significantly affect the frictional force on the back side of the document, and the amount of paper dust generated is considered to be the same as that of plain paper. is there.

Thus, in the present embodiment, the reading glass to be cleaned is determined according to the surface of the document on which paper dust is generated.
Then, only when the last document has passed over the reading glasses 41 and 61a, after the last document has passed, the cleaning members 59 and 62 are rotated by -1 respectively to provide the brushes provided on the cleaning members 59 and 62. Correcting the deformation of the portion 592 is the same as in the double-sided standard mode.

In this way, in the double-sided capacity enhancement mode, the reading glass 41 on which paper dust is easy to adhere is thoroughly cleaned, so that deterioration in image reading quality can be suppressed.
Returning to FIG. 7, if the value of the flag F is not “2” (step S109: NO), the value of the flag F is “3”, that is, indicates thin paper. In step S20, the separation pressure contact force Is lower than the standard value, so the generation of paper dust from the front side of the document is expected to decrease and the generation of paper dust from the back side is expected to increase. The reading surface cleaning / reading process is executed (step S111), and the process returns to the main routine.

FIG. 9C is a diagram for explaining the reading surface cleaning / reading process in the duplex capability changing mode, and the way of viewing the drawing is the same as in FIG. 9A.
As shown in FIG. 9C, the cleaning members 59 and 62 are rotated by +1 immediately before the first document passes over the reading glasses 41 and 61a.
Thereafter, every time the original passes through the reading glass 41, the operation of rotating the cleaning member 59 by +1 is repeated between the papers, and the cleaning member 62 is passed between the papers every time the original passes the reading glass 61a. Repeat the operation of rotating +1.

Then, only when the last document has passed over the reading glasses 41 and 61a, after the last document has passed, the cleaning members 59 and 62 are rotated by -1 respectively to provide the brushes provided on the cleaning members 59 and 62. Correcting the deformation of the portion 592 is the same as in the double-sided standard mode.
As described above, in the double-side capability changing mode, the cleaning frequency of the reading glass 61a, to which paper dust easily adheres, is increased, and the cleaning frequency of the reading glass 41, to which paper dust is difficult to adhere, is reduced. Therefore, it is possible to reduce the wear of the brush portion 592 of the cleaning member 59 and extend the life while suppressing the deterioration of the image quality on the back side of the document.

  As described above, in the copying machine 1 according to the first embodiment, the feeding pressure contact force and the separation pressure contact force are changed according to the difficulty of the maneuvering operation due to the thickness of the document. Thus, the fluctuation of the amount of paper dust generated from the front side and the back side of the document is estimated, and the cleaning frequency of the cleaning members 59 and 62 is set to an appropriate frequency according to the estimated amount of paper dust generated. Further, it is possible to reduce the wear of the brush portion 592 provided on the cleaning members 59 and 62 and to extend the life while maintaining the image reading quality on both sides of the document.

  In addition, conventionally, there is a case where an instruction for increasing the cleaning frequency more than usual, such as rotating the cleaning member three times at one cleaning timing, may be received from the user via the operation panel. Cases often arise after the user reads an image of a document, notices that the image quality has deteriorated due to paper dust, and increases the cleaning frequency when reading the image again.

  On the other hand, in the copying machine 1 of the present embodiment, the cleaning frequency of the reading glasses 41 and 61a is automatically adjusted when the user first inputs any of plain paper, thick paper, and thin paper. Therefore, the possibility of image reading failure is also reduced, and the document transport operation is not repeated any more, thereby extending the life of the brush unit 592 and contributing to the improvement of productivity.

(2) Second Embodiment (2-1) Configuration of Image Reading Device Hereinafter, an image reading unit 210 according to a second embodiment of the present invention will be described.
The configuration of the image reading unit 210 according to the second embodiment is basically the same as that of the image reading unit 2 according to the first embodiment, but the image reading unit 210 according to the second embodiment uses a simultaneous reading method. In place of the original document conveyance unit 5, a reverse type document conveyance unit 215 for reading a double-sided image by switching back and reversing the original document is provided, as well as a double-sided standard mode and a double-sided capability enhancement mode. In place of the reading surface cleaning / reading processing in the duplex capability changing mode, the reading surface cleaning / reading processing is executed in a reversing standard mode, a reversing capability enhancing mode, and a reversing capability changing mode, which will be described later.

In the following, common constituent parts will be denoted by the same reference numerals as those in the first embodiment, description thereof will be omitted, and differences will be mainly described.
(2-2) Configuration of Document Conveying Unit FIGS. 10A to 10C are operation diagrams of the image reading unit 210 according to the second embodiment.
As shown in FIG. 10A, the document conveying unit 215 of the image reading unit 210 is provided with a reversing path 64, and the document back side reading provided in the document conveying unit 5 of the first embodiment. The part 61 and the cleaning member 62 are not provided.

Therefore, when both sides of the document are read, as shown in FIG. 10B, after most of the leading end side of the document is discharged onto the document discharge tray 51, as shown in FIG. The document discharge roller pair 63 is reversed, the document is switched back, and again passes over the reading glass 41 to read the image on the back side of the document.
In addition, if the original on which the image on the back side is read is discharged as it is onto the document discharge tray 51, it is loaded with the original when reading only one side and the top and bottom of each sheet being reversed. As a result, the page order is out of order, and after another switchback operation (hereinafter referred to as “alignment reversal operation”), the document is discharged onto the document discharge tray 51.

As described above, since the document is reversed when the back side of the document is read or the alignment reversal operation is performed, the contents of the reading surface cleaning / reading process are different from those of the first embodiment.
Specifically, as described above, instead of the reading surface cleaning / reading processing in the standard mode for both sides, the capability enhancement mode for both sides, and the capability change mode for both sides, the standard mode for reversal and the capability enhancement for reversal shown below, respectively. The reading surface cleaning / reading process in the mode and the ability changing mode for reversal is executed.

FIG. 11A is a diagram for explaining the reading surface cleaning / reading process in the standard mode for reversal, and the way of viewing the drawing is the same as in FIGS. 8A to 8C.
As shown in FIG. 11A, the cleaning member 59 is rotated by +1 immediately before the first original passes over the reading glass 41, and thereafter, every time the original passes over the reading glass 41 an even number of times. The operation of rotating the cleaning member 59 by +1 is repeated between sheets.

Note that the document that passes through the reading glass 41 at a multiple of 3 is simply reversed so that the top / bottom relationship of the front and back is the same as that of the one-sided document, and this document is not read. Therefore, it is indicated by a broken line.
Then, only when the document has finally passed over the reading glass 41, after the last document has passed, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592 provided on the cleaning member 59. .

FIG. 11B is a diagram for explaining the reading surface cleaning / reading process in the reversal capability enhancement mode, and the way of viewing the drawing is the same as FIG. 11A.
As shown in FIG. 11B, the cleaning member 59 is rotated by +1 immediately before the first original passes over the reading glass 41. Thereafter, the front side of the original is read and then cleaned between sheets. The operation of rotating the member 59 by +2 is repeated.

At this time, since the cleaning time takes twice as long as the normal cleaning operation of rotating the cleaning member 59 by +1, it is necessary to make the interval between sheets longer than the standard mode for reversal.
Further, the cleaning operation of +1 rotation executed in the reversing standard mode is also executed at the same timing in the reversing capability enhancement mode, and the execution timing of this cleaning operation is the operation of rotating +2 times. When it overlaps with the timing, it is made to make a total of +2 rotations at that timing.

In this way, even in the case where the amount of paper dust generated from the surface of the document is expected to increase, paper dust can be removed firmly and the cleaning frequency can be reduced throughout the cleaning period. It is possible to prevent a period that temporarily falls below the standard mode for both sides.
Then, only when the document has finally passed over the reading glass 41, after the last document has passed, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592 provided on the cleaning member 59. This is the same as the standard mode for inversion.

Further, FIG. 11C is a diagram for explaining the reading surface cleaning / reading process in the reversal ability change mode, and the way of viewing the drawing is the same as in FIGS. 11A and 11B.
As shown in FIG. 11C, the cleaning member 59 is rotated by +1 immediately before the first original passes over the reading glass 41, and thereafter, after the back side of the original is read, the cleaning member is interposed between the sheets. The operation of rotating 59 by +2 is repeated.

Further, the cleaning operation is not performed until the surface of the original is read and then the original passes through the reading glass 41.
In this case, where the amount of paper dust generated from the front side of the original document is reduced and the amount of paper dust generated from the back side is expected to increase, the frequency of cleaning at the time of reading the back side is changed, By removing the paper dust and reducing the cleaning frequency at the time of reading the surface with little paper dust generation, an increase in the wasteful cleaning frequency as a whole can be suppressed, and a reduction in the life of the brush portion 592 can be suppressed.

Then, only when the document has finally passed over the reading glass 41, after the last document has passed, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592 provided on the cleaning member 59. This is the same as the standard mode for inversion.
(3) Third Embodiment (3-1) Configuration of Image Reading Apparatus Hereinafter, a document conveying unit according to a third embodiment of the present invention will be described.

The configuration of the document conveying unit according to the third embodiment is basically the same as that of the document conveying unit 5 according to the first embodiment. However, in the document conveying unit according to the third embodiment, the type of document from the user is Is not required, and further, the feeding pressure contact force and the separation pressure contact force are not changed, and the contents of the document conveying operation and the reading surface cleaning / reading process are different from those of the first embodiment.
As described above, since the document conveying unit according to the third embodiment of the present invention does not change the feeding pressure contact force and the separation pressing force, a mechanism for changing these pressures from the configuration of the document conveying unit 5 is provided. Since the omitted configuration has contents that can be easily considered by those skilled in the art, a description thereof is omitted here.

Further, in order to make the contents of the reading surface cleaning / reading process easy to understand, the document back surface reading unit 61 and the cleaning member 62 are omitted from the document conveying unit according to the third embodiment.
FIG. 12 is a flowchart illustrating an execution procedure of document conveyance processing in the document conveyance control unit of the document conveyance unit according to the third embodiment.

Note that the document conveyance control unit of the document conveyance unit according to the third embodiment is different from the document conveyance control unit 200 according to the first embodiment only in the contents of the execution program stored in the ROM 202, and is a hardware component. Since there is no change in terms of wear, the same reference numerals as those in the first embodiment are used for explanation.
When the main power is turned on, the document conveyance control unit 200 stands by until an instruction to read the document is received from the user via the operation panel 7 (step S301: NO), and when the instruction to read the document is received (step S301: NO). Step S301: YES) Wait until the document transport timing arrives (Step S302: NO). When the document transport timing arrives (Step S302: YES), a subroutine process for performing the document transport operation (hereinafter referred to as "document"). "Conveying process") is executed (step S303).

FIG. 13 is a flowchart showing an execution procedure of the document conveying process.
The document conveyance control unit 200 resets the count value N indicating the number of times that the feeding operation is repeated for one document to “0” (step S401), and drives the feeding roller driving unit 180, The rotation of the feeding roller 55a and the pickup roller 53 connected to the feeding roller 55a by a belt (not shown) is started and timing is started (step S402).

Then, the document detection sensor 56 determines whether or not the document is detected until the measured time reaches the predetermined time ta (step S403).
The predetermined time ta is a time obtained by adding a certain margin to the time required for the leading edge of the document to pass the detection position of the document detection sensor 56 when the document is normally fed out by one feeding operation. If the document detection sensor 56 does not detect the leading edge of the document after this time, it is considered that a paper feed error has occurred.

For this reason, if the leading edge of the document is detected by the document detection sensor 56 before the measured time reaches the predetermined time ta (step S403: YES), the document conveyance control unit 200 performs a normal feeding operation. Return to the main routine.
When the normal feeding operation is performed as described above, the registration roller pair 57, the conveyance roller pair 58, the conveyance roller pair 60, the document discharge roller pair 63, and the like are driven at a predetermined timing. Since this is the same operation as the conventional one, the description thereof is omitted.

  Further, if the leading edge of the document is not detected before the measured time reaches the predetermined time ta (step S403: NO), it is considered that a paper feed error has occurred, so that a jam does not occur. The pickup roller 53 and the feeding roller 55a are immediately stopped (step S404), and if the count value N is not equal to or greater than a predetermined value Na (Na is, for example, “3”) (step S405: NO), the count value N Is incremented by 1 (step S406), and the processing after step S402 is repeated to execute a so-called retry operation.

That is, in this embodiment, the user does not input the type of document, but it can be determined to some extent whether the type of document is thick paper by the count value N.
If the count value N is equal to or greater than the predetermined value Na (step S405: YES), even if the retry operation is continued further, it is unlikely that the feeding operation will be performed normally. A signal for notifying the occurrence of a paper feed error is output to the control unit 6 of the printer unit 3, and a message to that effect is displayed on the operation panel 7 (step S407).

  Returning to FIG. 12, the document conveyance control unit 200 stands by until the timing for cleaning comes (step S304: NO), and when the document is sent out from the registration roller pair 57 and the timing for cleaning comes (step S304). (S304: YES) If the count value N is “0” (step S305: YES), the original is normally fed out by one feeding operation, and therefore the reading glass in the standard mode shown in FIG. 41 is cleaned and the original is read (step S306). If the read original is the last of a series of originals for which a reading instruction has been received (step S307: YES), the original conveying process is terminated.

  If the count value N is not “0”, the document sent from the registration roller pair 57 has been retried, and at least the operating time during which the feeding pressure contact force is applied to the surface of the document is normal. Therefore, it is understood that the generation of paper dust from the surface is increasing. Therefore, the reading glass 41 is cleaned and the original is read in the capability enhancement mode shown below, and after step S307 Execute the process.

FIG. 14 is a view for explaining the cleaning of the reading glass 41 and the reading operation of the document in the capability enhancement mode, and the way of viewing the drawing is the same as in FIGS. 8A to 8C.
As shown in FIG. 14, until the original on which the retry operation has been performed (hereinafter referred to as “retry original”) passes over the reading glass 41, the same operation as in the standard mode shown in FIG. Then, the retry member passes over the reading glass 41, and the cleaning member 59 is rotated +1 times more than in the standard mode before the next document passes.

Then, only when the document has finally passed over the reading glass 41, after the last document has passed, the cleaning member 59 is rotated by −1 to correct the deformation of the brush portion 592.
As described above, in the capability enhancement mode according to the present embodiment, the reading original 41 is rotated by an extra +1 rotation of the cleaning member 59 between the sheets immediately after the retry original passes over the reading glass 41. It is possible to prevent the image reading quality from being deteriorated by being thoroughly cleaned.

<Modification>
(1) In the first embodiment, in the reading surface cleaning / reading process in the capability enhancement mode, the cleaning member 59 is rotated by +1 rotation between sheets each time one document passes over the reading glass 41, Although the cleaning frequency was increased, it is not limited to this.
For example, as shown in FIG. 15A, in the original standard mode, in other rotation operations except the +1 rotation operation performed before the document passes the reading glass 41 and the -1 rotation operation performed last. The cleaning frequency may be increased by rotating the cleaning member 59 where it should be rotated +1 +2 times.

In that case, since the cleaning time becomes longer than that in the standard mode, it is necessary to increase the gap between sheets.
Alternatively, as shown in FIG. 15B, the timing for cleaning the reading glass 41 and the rotation of the cleaning member 59 may be the same as in the standard mode, and the speed at which the cleaning member 59 is rotated may be slower than in the standard mode. Absent.
In the same figure, the width of the arrow is shown large, but this shows a state where the cleaning member 59 is slowly rotated over time, and when the cleaning member 59 is slowly rotated in this way, the standard is shown. It is possible to clean more reliably than the mode.

  In view of the above, as a countermeasure when an increase in the amount of paper dust is expected, in addition to increasing the frequency of cleaning the reading glass, the cleaning speed is reduced by decreasing the rotation speed of the cleaning member, etc. In short, it is only necessary to increase the cleaning ability, and this can be applied as the above-described countermeasure in the double-sided capacity enhancement mode, the double-sided capacity change mode, the reversal capacity enhancement mode, and the reversal capacity change mode. .

(2) In the third embodiment, the document transport unit does not change the feeding pressure contact force and the separation pressure contact force. Therefore, a mechanism for changing these pressure contact forces may be omitted from the configuration of the document transport unit 5. However, the present invention is not limited to this, and similarly to the first embodiment, the feeding pressure contact force and the separation pressure contact force may be changed.
For example, if the count value N is equal to or greater than a predetermined value Na in step S405 of the flowchart illustrating the procedure for executing the document conveyance process in FIG. 13, the feeding operation may be normally performed even if the retry operation is further performed. Since it is low, the document conveying operation is terminated and a signal for notifying the occurrence of a paper feed error is output to the operation panel 7 via the control unit 6, but is smaller than Na and 2 or more. When the value Nb (Nb is an integer) is set and the count value N is greater than or equal to Nb, the feed pressure contact force or both the feed pressure contact force and the separation pressure contact force are increased from the reference value to supply You may change to the state where a paper mistake is easy to be eliminated (henceforth "feed condition change").

In this case, even if the original is fed out as a result of the retry operation, the original fed out without changing the feeding condition and the original fed out after changing the feeding condition are compared with the latter than the former. Since the paper rubs the original more strongly, it is expected that the amount of paper dust generated will increase.
Therefore, when the cleaning ability is increased by performing the retry operation, the cleaning ability in the case where the feeding condition is changed and transported without changing the feeding condition (see FIG. 14). It is desirable to increase the degree of increase.

FIGS. 16A and 16B are diagrams illustrating an example in which the degree of increase in the cleaning capability is set large when the feeding condition is changed as described above.
Here, the “retry document” in the capability enhancement mode of FIGS. 16A and 16B is a feeding condition that increases the feeding pressure contact force or both the feeding pressure welding force and the separation pressure welding force in the process of repeating the retry operation. Indicates a document that has been changed.

In the capability enhancement mode shown in FIG. 16A, the cleaning member 59 is rotated +2 times between the sheets of paper until the original reaches the reading glass 41 after the retry original passes through the reading glass 41, The cleaning capability is further enhanced as compared with the capability enhancement mode (see FIG. 14) when the feeding condition change is not performed.
In the capacity enhancement mode shown in FIG. 16B, the feeding condition is changed as a result of rotating the cleaning member 59 +1 between all the sheets after the retry original passes through the reading glass 41. The cleaning ability is higher than when it was not done.

(3) The document conveying unit in the third embodiment is configured such that the document back side reading unit 61 and the cleaning member 62 are omitted. However, the present invention is not limited thereto, and includes the document back side reading unit 61 and the cleaning member 62. It is good also as a structure.
In that case, if it is expected that the amount of paper dust generated on the back side of the document will increase more than usual, the capability enhancement mode as shown in FIG. 14 is applied to the cleaning operation of the cleaning member 62. Good.

Further, in the configuration of the modification (2) in which the feeding pressure contact force and the separation pressure contact force can be changed, when the amount of paper dust generated on the back side of the document is expected to increase more than usual, What is necessary is just to apply the capability enhancement mode of Fig.16 (a) or (b) to the cleaning operation | movement of the cleaning member 62. FIG.
(4) In the first to third embodiments, the cleaning capability of the cleaning member is changed by paying attention only to the increase / decrease of the feeding pressure contact force and the separation pressure welding force and the operating time of the feeding pressure contact force on the document. Not limited to this.

  For example, when the original is an OHP sheet, no paper dust is generated, and when the original is a coated paper or the like, paper dust is less likely to be generated. In some cases, even if the feeding pressure contact force and the separation pressure contact force are increased, the transition to the mode for increasing the cleaning ability of the cleaning member is not performed, or the cleaning ability of the cleaning member is increased. The increase width may be reduced.

In this case, the user may input via the operation panel 7 that the paper type of the document is an OHP sheet or coated paper.
Further, as described above, the focus on the increase / decrease of the feeding pressure contact force and the separation pressure welding force and the working time of the feeding pressure contact force on the document are the pickup roller 53, the feeding roller 55a and the separation roller 55b, and the surface of the document. This is because the amount of paper dust generated was estimated from the increase / decrease in friction, but the surface of these three rollers was worn while being used, the friction coefficient gradually decreased, and paper dust was hardly generated. Therefore, the content of the capability enhancement mode may be set as follows by estimating a decrease in the friction coefficient of the surface of the pickup roller 53 from the number of feedings (wear degree index value) and the like.

FIG. 17A is a diagram schematically showing the relationship between the integrated value (horizontal axis) of the number of document feeds and the friction coefficient (vertical axis) of the outer peripheral surface of the pickup roller 53.
As shown in the figure, it can be seen that the coefficient of friction of the outer peripheral surface of the pickup roller 53 decreases exponentially.
Here, the friction coefficient value of the outer peripheral surface of the pick-up roller 53 in the initial state is set to μ0, the integrated value of the number of feedings at which the decrease in the friction coefficient is dull is set to M1, and the friction coefficient value at this time is set to μ1.

Further, when the service life of the pick-up roller 53 is M2, the friction coefficient of the peripheral surface when the service life is reached is μ2.
FIG. 17B is a diagram showing the relationship between the coefficient of friction (horizontal axis) of the outer peripheral surface of the pickup roller 53 and the amount of paper dust (vertical axis) generated from the document by a predetermined number of feeding operations.
As shown in the figure, it can be seen that the amount of paper dust generated increases approximately logarithmically.

Here, the generation amounts of paper dust corresponding to the friction coefficient values μ0, μ1, and μ2 are S0, S1, and S2, respectively.
As shown in FIG. 17 (a), since the change in the friction coefficient of the outer peripheral surface of the pickup roller 53 is large until the number of times of feeding reaches M1, using the graphs shown in FIGS. 17 (a) and (b), The amount of paper dust generated may be estimated from the integrated value of the number of feeds, and the cleaning capability of the cleaning member may be changed according to the estimated amount of paper dust generated.

In addition, when the number of times of feeding becomes M1 or more, as schematically shown in FIG. 17 (b), the amount of paper dust generated decreases rapidly, so that the amount of feeding pressure and separation pressure is increased. Even in such a case, the transition to the mode for increasing the cleaning capability of the cleaning member may not be performed, or the increase width of the cleaning capability of the cleaning member may be reduced.
Moreover, since the same tendency as that shown in FIGS. 17A and 17B is applied to the feeding roller 55a and the rolling roller 55b, the contents applied to the pickup roller 53 are applied to these rollers. can do.

(5) In the first and second embodiments, the feeding pressure contact force and the separation pressure contact force are changed by moving the pickup roller 53 and the rolling roller 55b up and down.
However, as described in the modification example (4), even when the pickup roller 53, the feeding roller 55a, and the roller 55b are worn during use, even when they are changed up and down by the same amount. Since the outer diameter is different between the non-wearing state and the advanced wear state, there is a difference in the values of the feeding pressure contact force and the separation pressure contact force, and the value in the advanced wear state is smaller than in the non-wearing state. .

For this reason, it is desirable to estimate the outer diameter change due to the wear of these rollers according to the number of times of feeding, and to correct the vertical amounts of the pickup roller 53 and the feeding roller 55a.
FIG. 18A is a diagram schematically showing the relationship between the integrated value (horizontal axis) of the number of document feeds and the outer diameter (vertical axis) of the pickup roller 53.

As shown in the figure, it can be seen that the outer diameter of the pickup roller 53 decreases almost exponentially.
Here, the outer diameter of the pickup roller 53 in the initial state is set to D0, and the integrated value of the number of feedings at which the decrease in the outer diameter is dull is set to M3. At this time, the outer diameter of the pickup roller 53 is set to D3.

Furthermore, let D2 be the outer diameter of the pickup roller 53 when the pickup roller 53 has reached the service life M2.
FIG. 18B is a diagram schematically showing the relationship between the outer diameter (horizontal axis) of the pickup roller 53 and the feeding pressure contact force (vertical axis) in the reference state.
As shown in the figure, it can be seen that the feeding pressure contact force increases approximately logarithmically.

Here, the values of the operation pressure contact force in the reference state corresponding to the outer diameters D0, D2, and D3 are P0, P2, and P3.
As shown in FIG. 18 (a), since the change in the outer diameter of the pickup roller 53 is large until the number of feeding reaches M3, the graphs shown in FIGS. 18 (a) and (b) are used. It is desirable to estimate the outer diameter change and correct the vertical movement amount of the pickup roller 53 so that the value of the operation pressure contact force in the reference state becomes P0.

In this case, when the document conveyance control unit outputs signals corresponding to the protrusion amounts L2 and L3 of the rod 156a from the position detection unit, the radius of the pickup roller 53 obtained based on the graph of FIG. What is necessary is just to review the drive control of the raising / lowering plate drive part 152 so that the raising / lowering plate 52 may be raised upward by the reduction | decrease.
Further, when the number of times of feeding becomes M3 or more, as shown in FIGS. 18 (a) and 18 (b), the outer diameter of the pickup roller 53 changes from D3 to D2. However, since the amount of change is relatively small, the adjustment performed after the number of feeds exceeds M3 may be omitted.

Moreover, since it is the same tendency as what was shown in FIG. 18 (a) and (b) also about the feeding roller 55a and the rolling roller 55b, the content applied to the said pickup roller 53 is applied also to these rollers. be able to.
(6) In the above embodiment, the document conveyance control unit 200 is provided in the document conveyance unit 5, but the present invention is not limited to this.

The control system provided in the image reader unit 4 or the printer unit 3 may also serve as the document conveyance control unit 200.
(7) In the first to third embodiments, the roller pair 55 is configured to press-contact the feeding roller 55a and the roller 55b to which the torque limiter is attached in order to form a separation nip. However, the present invention is not limited to this, and a configuration may be adopted in which a pressure pad or the like whose surface is set to a predetermined friction coefficient is pressed against the feeding roller 55a instead of the separation roller 55b. As long as there is a roller that is rotationally driven and a conveyance resistance member that contacts the roller and suppresses the movement of the document, it may be anything.

(8) In the first and second embodiments, the user inputs whether the original corresponds to plain paper, thick paper, or thin paper using the operation panel 7. A thickness detection unit such as an ultrasonic thickness detector may be provided in the apparatus, and information on the thickness of the document may be acquired by directly detecting the thickness of the document.
As a configuration of the thickness detection unit, the thickness may be detected by pressing the original placed on a flat guide surface with a probe that transmits and receives ultrasonic waves from the upper side so that the original is in close contact with the guide.

As a position where the probe is pressed, the position closest to the downstream side of the roller pair 55 is desirable.
This is because the document is stopped during the period from the completion of the operation of forming the loop by bringing the leading edge of the document into contact with the registration roller pair 57 until the rotation of the registration roller pair 57 is started. This is because even if the probe is pressed against the document during this period, it does not hinder the transport of the document.

Note that the operation of pressing the probe against the document can be easily realized by using an actuator such as an electromagnetic solenoid.
By the way, a paper feed error is often caused by a large original thickness, that is, a large basis weight.
Therefore, when the number of repetitions of the retry operation performed when a paper feed error occurs is large as in the case of the document conveying unit of the third embodiment, it is estimated that the paper is thick paper.

In other words, the number of repetitions of the retry operation is considered to indicate the thickness of the document to some extent.
As described above, the acquisition means for acquiring the thickness of the document may be a means for counting the number of times the retry operation is repeated, in addition to the operation panel and the thickness detection unit.
In the third embodiment, by repeating the retry operation, the action time of the feeding pressure contact force on the document is lengthened and the probability that the document is fed is increased. For example, the paper of the document input from the operation panel is increased. If the seed is thick paper, the rotation time of the pick-up roller from the beginning of the document conveying operation is longer than usual, and the action time of the feeding pressure contact force on the document is increased to increase the probability that the document is fed out. Good.

(9) In the first and second embodiments, the paper type of the original received by the operation panel is any one of plain paper, thin paper, and thick paper. An input of paper or the like may be accepted.
High-quality paper has a smoother surface, a smaller friction coefficient, and is more likely to cause paper feed errors than renewed paper, so the difficulty in feeding out the original is equivalent to that of thick paper. It may be carried out.

  (10) Also, in the modified example (2), when a paper feed error occurs, the working time of the feeding pressure contact force is made longer than usual, and the cleaning ability of the reading glass is enhanced. When it occurs continuously and the number of retries is Nb or more, the feeding pressure contact force, or both the separation pressure welding force and the feeding pressure welding force are increased, and the reading glass cleaning ability is further enhanced.

After that, if the paper feed error is resolved, the changed feeding pressure contact force, separation pressure welding force and feeding pressure welding force operating time, and the reading glass cleaning ability are returned to the standard values. Not exclusively.
For example, if the feeding operation becomes more difficult as the retry operation is repeated Nb times or more, there may be a special situation such as the rigidity of the original being higher than that of normal thick paper. Since there are many cases where it is easy to generate, even if the feeding error is resolved after repeating the retry operation Nb times or more, the feeding pressure contact force, the separation pressing force, the working time of the feeding pressure contact force, and the cleaning ability of the cleaning member Instead of returning to the reference value, it may be maintained until the original reading job is completed so that the next paper feed error is unlikely to occur.

In addition, whether to select the control that makes it difficult for the next paper feeding error to occur or the control as in the modified example (2) is selected via a receiving unit such as an operation panel, for example. It may be determined by receiving an instruction from.
(11) In the above-described embodiment, when it is estimated that the adhesion of paper dust to the reading glass is reduced in the capability suppression mode, the double-side capability changing mode, and the reversing capability changing mode, the cleaning capability for the reading glass is increased. Although it is lower than the reference value, it is not always necessary to reduce the cleaning ability in this way.

  (12) In the above-described embodiment and modification, only the difficulty of the maneuvering operation caused by the paper type of the document is a problem. Since the friction coefficient of the document surface, the pickup roller, the feeding roller 55a, and the separating roller 55b tends to increase, double feeding is likely to occur, and if the document is curled, the Mistakes are likely to occur.

Thus, since the difficulty of the feeding operation is affected by the use environment of the image reading apparatus and the state of the document, the difficulty of the feeding operation may be determined including these factors.
(13) In the above embodiment, a copying machine has been described as an example of an image forming apparatus provided with an image reading apparatus. However, the present invention is not limited to this, and can also be applied to an image forming apparatus such as a facsimile. .

  Further, the contents of the above embodiment and the above modification may be combined as much as possible.

  The present invention can be applied to an image reading apparatus including a mechanism for cleaning an image reading surface of a document by rotating a brush and an image forming apparatus including the image reading apparatus.

DESCRIPTION OF SYMBOLS 1 Copier 2,210 Image reading part 3 Printer part 4 Image reader part 5,215 Document conveyance part 6 Control part 7 Operation panel 41, 61a Reading glass 59, 62 Cleaning member 50 Document feed tray 51 Document discharge tray 52 Lifting Plate 53 Pickup roller 55 Rolling roller pair 55a Feeding roller 55b Rolling roller 56 Document detection sensor 57 Registration roller pair 58 Conveying roller pair 60 Conveying roller pair 61 Document back side reading unit 152 Lift plate driving unit 156 Position detecting unit 160 Rotating member 162 Rotation Member drive unit 180 Feed roller drive unit 181 Registration roller drive unit 182 Transport roller drive unit 183 Paper discharge roller drive unit 190 First cleaning member drive unit 191 Second cleaning member drive unit 200 Document transport control unit 592 Brush unit

Claims (16)

The document placed on the document tray is brought out on the conveyance path with the pickup roller in contact with the upper surface thereof, and then introduced into the separation portion where the feeding roller and the conveyance resistance member are pressed against each other. The original is further transported downstream in the transport direction, and passes through the reading position of the strip-shaped reading glass provided along the direction orthogonal to the transport direction. A sheet-through type image reading apparatus that reads an image of the document by a provided reading unit,
A brush that removes foreign matter on the surface of the reading glass as the rotating body rotates is attached to a rotating body that is rotatably supported about an axis parallel to a direction orthogonal to the conveying direction. A cleaning member provided in a row along the rotation axis direction;
Driving means for rotationally driving the rotating body;
Depending on the information about the difficulty of the delivery operation, the second pressure acting between the first pressing force, the conveying resistance member and the feeding roller acting between said pick-up roller the document A condition changing means for changing a condition for changing at least one feeding condition from a reference value out of a working time in which the force and the first pressing force are applied to one original;
In the reference state in which the condition change is not performed by the condition changing means, the reading glass is cleaned with a reference cleaning ability, and paper dust is generated from the document due to the condition change being performed. And a cleaning control means for controlling the driving means so as to clean the reading glass with a cleaning ability higher than the reference cleaning ability. Reader. The cleaning control means includes
By executing at least one of a decrease in the rotation speed of the rotating body, an increase in execution frequency of the rotating operation of the rotating body within a unit time, and an increase in the number of rotations of the rotating body in one rotating operation, The image reading apparatus according to claim 1, wherein the cleaning ability is higher than a reference cleaning ability. The cleaning control means includes
When the occurrence of paper dust from the document is less than the reference state due to the condition change unit performing the condition change, the reading performance is lower than the reference cleaning ability. The image reading apparatus according to claim 1, wherein the driving unit is controlled so as to clean the glass. The condition changing means includes
When a paper feeding error occurs where the document feeding operation is not performed normally, a retry operation that repeats the feeding operation for the same document is executed, thereby increasing the time for applying the first pressure contact force to one document. performs the conditions change so that,
4. The image reading apparatus according to claim 1, wherein the cleaning control unit regards that the generation of paper dust from the document increases as the operation time increases. 5. In the condition changing means, the first pressure contact force increases from a reference value for additional retry operations after the number of repetitions of the retry operation reaches a predetermined number N (N is an integer of 2 or more). The image reading apparatus according to claim 4, wherein the condition is changed as follows. The cleaning control means includes
Only when cleaning is performed immediately after an image of a document conveyed after the feeding error has been eliminated by the additional retry operation, the cleaning performance is higher than the cleaning capability when the number of repetitions of the retry operation is 1 or more and less than N. 6. The image reading apparatus according to claim 5, wherein the reading glass is cleaned with a larger cleaning ability, and thereafter, the cleaning ability is controlled to return to the reference cleaning ability. The cleaning control means includes
The number of repetitions of the retry operation is 1 or more from the time of cleaning immediately after the image of the document conveyed after the feeding error is eliminated by the additional retry operation until the completion of the current document reading job. 6. The image reading apparatus according to claim 5, wherein the reading glass is cleaned with a cleaning ability larger than a cleaning ability when the ratio is less than N. 6. The reading unit is provided on a first surface side of a document that passes through the conveyance path, and includes a first reading unit that reads an image on the first surface of the document and a second surface side of the document that passes through the conveyance path. And a second reading unit that reads the second surface of the document,
The cleaning member includes a first cleaning member for cleaning the reading glass in the first reading unit, and a second cleaning member for cleaning the reading glass in the second reading unit,
The pickup roller and the feeding roller are arranged on the first surface side of the document,
The cleaning control means includes
When the condition change corresponds to at least one of an increase in the first pressing force, an increase in the second pressing force, and an increase in the operation time, the cleaning capability of the first cleaning member is the reference cleaning capability. The image reading apparatus according to claim 1, wherein the image reading apparatus is controlled so as to increase. The condition changing means includes
If there is a possibility that the document will be double-fed, change the feeding condition so as to reduce the second pressure contact force,
The cleaning control means includes
9. The control according to claim 8, wherein when the second pressure contact force is reduced by the condition changing unit, the cleaning capability of the second cleaning member is controlled to be greater than the reference cleaning capability. Image reading device. A reversing introduction means for performing a reversing operation for reversing the front and back of the document and introducing it to the reading position;
The pickup roller and the feeding roller are disposed on the first surface side of the document,
When the reversing operation is performed, the cleaning control means
When the change in the feeding condition corresponds to at least one of an increase in the first pressing force, an increase in the second pressing force, and an increase in the operation time, the first surface of the document is read for the first time thereafter. The control is performed so that the cleaning ability of the cleaning member increases from the reference cleaning ability until the next reading of the second side of the document is started. 8. The image reading apparatus according to any one of 7 above. The condition changing means includes
If there is a possibility that the document will be double-fed, change the feeding condition so as to reduce the second pressure contact force,
It said cleaning control means
After the condition changing means reduces the second pressure contact force, the first time the second surface of the original is read and the time when the first surface of the next original starts to be read, the cleaning member The image reading apparatus according to claim 10, wherein the cleaning capability is controlled to be greater than the reference cleaning capability. An acquisition means for acquiring the paper type of the document;
The cleaning control means includes
The image reading apparatus according to claim 1, wherein the difficulty of the feeding operation is specified based on the acquired paper type. The paper type is the thickness of the document,
The image reading apparatus according to claim 12, wherein the acquisition unit includes a thickness detection unit that detects the thickness of the document.   The image reading apparatus according to claim 12, wherein the acquisition unit is an operation panel. A wear degree index value acquisition means for acquiring a wear degree index value indicating the wear degree of the pickup roller and the feeding roller,
The cleaning control means includes
15. When the wear degree index value is equal to or greater than a predetermined value, the control for increasing the cleaning ability with the change of the condition is prohibited, and the reference cleaning ability is maintained. An image reading apparatus according to claim 1.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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