Patent Grant
8840103
The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2012-212650 filed in Japan on Sep. 26, 2012.
1. Field of the Invention
The present invention relates to a sheet conveying device and an image forming apparatus, and more particularly, a sheet conveying device suitable for a document conveying device for conveying a document sheet to a scanning position of an image reading device at a conveying speed at which the image can be read, and relates to an image forming apparatus using the sheet conveying device.
2. Description of the Related Art
In the past, a sheet conveying device serving as a document conveying device capable of separating each sheet from a bundle of cut sheet-like document sheets, and continuously feeding the sheet to an image scanning position of an image forming apparatus such as a copier, a facsimile machine, and the like, is well known. In this kind of sheet conveying device, a known sheet conveying device is one having a paper feeding belt and a separation roller used in a mechanism for separating a document sheet from the document bundle and pressing a holding in which a paper feeding belt is set in a direct manner or with a link mechanism so as to change a separation pressure which is set by a contact angle (nip angle) of a nip portion between the paper feeding belt and the separation roller.
For example, Japanese Patent No. 4152604 discloses a mechanism for releasing pressure of a paper feeding belt while preventing skew and adjusting a contact angle at a nip portion of a separation roller using a pair of cams provided in a proximity of the paper feeding belt so as to allow adjustment of the contact angle of the nip portion between a paper feeding belt and the separation roller using this pressure release mechanism.
However, in such sheet feeding device and image forming apparatus capable of feeding sheets continuously as described above, the separation pressure which is set by the contact angle of the nip portion of the paper feeding belt and the separation roller of the separation feeding device can be changed and set, but the contact angle at the nip portion of the paper feeding belt and the separation roller thus set cannot be accurately maintained while the sheets are being passed. For this reason, the contact angle of the nip portion of the paper feeding belt and the separation roller may change while the sheets are fed, and there is a problem in that the separation pressure may change.
Accordingly, the present invention is to provide a sheet conveying device and an image forming apparatus capable of appropriately holding a contact angle of a nip portion of the paper feeding belt and the separation roller during separation of sheets and obtaining preferable separation pressure at all times.
It is an object of the present invention to at least partially solve the problems in the conventional technology.
According to an aspect of the invention, a sheet conveying device is provided. The sheet conveying device includes: a separation sheet feeding mechanism having a paper feeding belt and a separation roller, wherein when there are not only a sheet which is in contact with the paper feeding belt and is to be fed but also a subsequent sheet in contact with the separation roller, the separation sheet feeding mechanism uses the feeding belt to feed the sheet which is to be fed, and uses the separation roller to separate the subsequent sheet from the sheet which is to be fed; and an adjustment mechanism that changes contact state of the paper feeding belt to the separation roller by changing relative position of the paper feeding belt and the separation roller, and changes and adjusts separation performance of the separation roller for the subsequent sheet, wherein the adjustment mechanism includes a cam follower member changing the relative position of the feeding belt and the separation roller in accordance with the rotation angle position of the cam member and the rotating cam member, the cam member includes a first cam face and a second cam face which are formed at each rotation radius position in accordance with the rotation angle position, and are spaced apart in the rotation radius direction, and the cam follower member has a contact unit guided by the first cam face and the second cam face to a lift position in accordance with a rotation angle position of the cam member from both sides in the rotation radius direction.
The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.
Hereinafter, a preferred embodiment of the present invention will be explained with reference to drawings.
As illustrated in
The image forming apparatus main body 51 includes a placed document image scanning unit 55 having contact glass 54 at the upper side thereof and a first conveyed document image scanning unit 56 located at a side of the placed document image scanning unit 55, which are not shown in details.
Then, when a document image is ready by the placed document image scanning unit 55 or first conveyed document image scanning unit 56, the digital MFP 50 executes well-known electrophotographic image forming processing based on the image data, and can record (print) the scanned image onto a predetermined recording sheet and transfer/output an image file.
The image forming apparatus main body 51 of the digital MFP 50 uses a main body control unit 111 provided therein to control operation of the placed document image scanning unit 55, the first conveyed document image scanning unit 56, and the like, and can form, for example, an electrostatic latent image on a photosensitive drum, not shown, based on a scanned document image provided by the placed document image scanning unit 55, develop the electrostatic latent image using toner, and record an image by transferring and fixing the toner image onto a predetermined recording sheet.
The placed document image scanning unit 55 exposes and scans the lower face of the document on the contact glass 54 in the main scanning and the sub-scanning direction, and achieves the functions of a well-known flatbed scanner for reading the document image.
The first conveyed document image scanning unit 56 achieves the functions of a well-known DF scanner for reading an image on the front face side of the document which is automatically being conveyed.
The first conveyed document image scanning unit 56 includes a slit glass 57 and a front face scanning unit 58. the slit glass 57 is for reading a front face image arranged at a side of the contact glass 54 in parallel therewith. When the switched-back document sheet is conveyed in the sub-scanning direction at a predetermined speed while passing the scanning position 20 on the slit glass 57, the document image on the front face is scanned by the front face scanning unit 58 in the main scanning direction from the lower side, as in the figure, through the slit glass 57.
Hereinafter, the configuration of the document conveying device 52 which is an embodiment of a sheet conveying device of the present invention will be explained.
As illustrated in the front side cross sectional configuration diagram illustrating the schematic configuration thereof in
The document set unit A is in a shape of a document set base on which at least one cut sheet-like document, which is to be read, such as a bundle of multiple documents to be read (hereinafter simply referred to as document bundle) can be placed, and the document to be read bundle is configured to be set thereon at a position where the sheets can be fed in such a manner that one of the document faces such as the front face which is the scanned face in a case of a single sided original (hereinafter simply referred to as front face) is at the upper side.
The separation feeding unit B separates the uppermost document from the document bundles set on the document set unit A, and feeds the separated document into an entrance of a document conveying path.
The registration unit C has a function of adjusting the documents successively fed from the separation feeding unit B into a predetermined conveying posture with primary abutment, and also has a function of pulling and conveying the aligned document to a downstream side.
The turn unit D has a reverse conveying function for reversing the document so that the front face thereof is at the lower side in
The first scan conveying unit E conveys the document 1, which has been switched back and conveyed from the turn unit D, at a predetermined speed in the sub-scanning direction while conveys the document 1 over the scanning position 20 on the slit glass 57.
When the document 1 is a both-sided document, the second scan conveying unit F scans the back face image of the document at a downstream side with respect to the main scanning position of the front face image through platen glass for reading back face image, not illustrated, in the main scanning direction from the diagonally upper side in
The discharging unit G discharges, to the stack unit H, the document 1 which has been read by the first scan conveying unit E and the second scan conveying unit F.
The stack unit H successively stacks the documents 1, which are successively discharged from the discharging unit G, in such a manner that the front face thereof is at the lower side, and as a result, the sheet bundle of the documents 1 is stacked in the same order in which the pages are arranged when the sheet bundle is set on the document set unit A but, in terms of the entire sheet bundle, the direction of the document face is upside down.
More specifically, As illustrated in
In this case, on the document table 2, at least one sheet, for example, a sheet bundle-like document 1 carrying multiple document sheets is set in such a manner that the document image face is at the upper side. The movable table 3 is configured to move in the vertical direction as illustrated by arrows a, b in
Both sides of the document 1 in a width direction perpendicular to the document conveying direction are positioned and guided by a movable guide member, not illustrated. When the leading end portion of the document 1 is inserted into the entrance portion of the separation feeding unit B opened, the set detection feeler 4 and the document set sensor 5 detect that the document 1 has been set, and this is transmitted via an interface circuit 107 to the main body control unit 111.
In a proximity of the document stacking surface of the document table 2, size detection sensors 30, 31, 32 are provided to detect the document size by identifying the end position of the document. The size detection sensors 30 to 32 may be a reflection-type sensor for performing detection without coming into contact with the document using optical means and a contacting actuator-type sensor capable of detecting even one sheet. The size detection sensors 30 to 32 are arranged to be able to detect whether the arrangement of the document is in the vertical direction or in the horizontal direction.
From the separation feeding unit B to the discharging unit G, multiple conveying guides 35, 36, 37, 38, 39, 41, 42, 43 are provided to guide the conveyed document to the predetermined feed path.
The separation feeding unit B includes upstream side portions of the multiple conveying guides 35, 36, a pick-up mechanism 7 capable of calling and conveying, in the document conveying direction, the uppermost document from the documents 1 placed on the document table 2, a feeding appropriate position sensor 8 for detecting whether an appropriate height (feeding appropriate position) maintained or not at which the uppermost document of the documents 1 raised by the movable table 3 is in contact with the pick-up mechanism 7, and a separation sheet feeding mechanism 9 for separating, from the other document sheets, one of the document sheets of the uppermost documents called and conveyed by a pick-up roller 73.
As illustrated in
The separation sheet feeding mechanism 9 includes a rotation driving shaft 71 serving as a separation driving shaft, a paper feeding belt holder bracket 92 (paper feeding belt holder) axially supported by the rotation driving shaft 71 at the proximal end side, a movable side belt support shaft 93 supported by the leading end side of the paper feeding belt holder bracket 92, a driven pulley 94b rotatably supported by the pulley 94a and the movable side belt support shaft 93 at the driving side fixed to the rotation driving shaft 71, an endless paper feeding belt 95 wrapped around both of the pulleys 94a, 94b, and a reverse roller 96 (separation roller; see
The paper feeding belt holder bracket 92 includes right and left side wall portions 92a, 92b axially supported by the rotation driving shaft 71 and a connection wall portion 92c connecting both of the side wail portions 92a, 92b, and can swing in the vertical direction with respect to the rotation driving shaft 71. The movable side belt support shaft 93 is supported in such a manner that the both end portions 93a (only one end of which is illustrated) can slide to the right and left side wall portions 92a, 92b of the paper feeding belt holder bracket 92. Between the right and left side wail portions 92a, 92b of the paper feeding belt holder bracket 92 and the both end portions 93a of the movable side belt support shaft 93, a belt tension giving compression coil spring 97 is fixed with a predetermined assembly load so that a predetermined tension is given to the paper feeding belt 95.
The tension (belt tension) acting on the paper feeding belt 95 is in accordance with the load of the belt tension giving compression coil spring 97 and the contact angle of the reverse roller 96 to the paper feeding belt 95, i.e., so-called nip angle at which the paper feeding belt 95 of the predetermined tension wraps around the front surface of the reverse roller 96, and the contact angle of the reverse roller 96 to the paper feeding belt 95 is adjusted by a separation pressure adjustment mechanism 60 (adjustment mechanism) explained later.
The registration unit C includes a separation sensor 33 for detecting a document 1 separated by the separation feeding unit B from the subsequent document bundle on the document table 2, an intermediate portion (having no numeral attached) in the document conveying direction of multiple conveying guides 35, 36, a document abutment sensor 11 for detecting the leading end of the document 1 when the document 1 separated by the paper feeding belt 95 comes in to a proximity of the pull-out roller 12, a pull-out roller 12 for pulling and conveying, in the document conveying direction along the conveying guides 35, 36, the document 1 from the subsequent document bundle when the document 1 of which leading end is detected by the document abutment sensor 11 is pressed against the pull-out roller 12, and multiple document width sensors 13 provided in accordance with the setting number of the sheet size of the document 1 so that the document width sensors 13 are spaced apart from each other in the main scanning direction perpendicular to the document conveying direction. The pull-out roller 12 is driven by reverse rotation of the sheet feeding motor 102.
In this case, the document abutment sensor 11 can read times when the leading end and the trailing end of the document 1 pass the document abutment sensor 11, and the controller counts the motor pulses between the time when the leading end passes and the time when the trailing end passes, thus detecting the length of the document in the conveying direction. The document width sensors 13 are configured such that, for example, the light is selectively shielded in accordance with the sheet size by the document 1 while the multiple document width sensors 13 are arranged in the depth direction of the digital MFP 50, and thus capable of detecting the width direction size perpendicular to the conveying direction of the document conveyed by the pull-out roller 12.
The turn unit D includes a bent portion at the downstream side of the conveying guides 35, 36, an intermediate roller 14 provided in a proximity of the bent portion, conveying guides 37, 41 folding back the document feed path at the downstream side of the conveying guides 35, 36, a scanning entrance roller 16 for conveying the document sheet in the conveying guides 37, 41 to the first scan conveying unit E, and a registration sensor 17 for detecting the leading end of the document sheet at the downstream side of the scanning entrance roller 16, and identifying a time when the leading end thereof reaches the scanning position 20. The intermediate roller 14 includes multiple pairs of rollers for conveying the document conveyed by the pull-out roller 12 into the bent portion at the downstream side of the conveying guides 35, 36, and each of the roller pairs are arranged to be in a proximity of each other so as to be in contact with both surfaces of the document sheet, and the multiple roller pairs are spaced apart from each other in the rotation shaft line direction perpendicular to the document conveying direction. The pull-out roller 12 and the other rollers likewise include multiple pairs of rollers.
The first scan conveying unit E include the slit glass 21 for reading the front face image, the conveying guide 42 provided at the opposite thereto, a scanning roller 19 for conveying the document conveyed to a position close to the slit glass 21 while the document is brought into contact with the slit glass 21, a scanning exit roller 23 for conveying a portion of the document sheet having passed the slit glass 21 to the second scan conveying unit F, and the conveying guide 38 provided at the opposite to the downstream side portion of the conveying guide 42.
The second scan conveying unit F includes a back face scan unit 25 (back face document reading device) including a back face image scanning contact-type image sensor (CIS) arranged between the conveying guide 38, 42 and the conveying guide 39, 43, a scanning roller 26 arranged at the opposite to and in a proximity of the platen glass of the back face scan unit 25 (of which details are not illustrated), and a CIS exit roller 27 rotating substantially in synchronization with the scanning roller 26 so that the sub-scanning direction conveying speed of the document 1 of which back face document is scanned in the main scanning direction by the back face scan unit 25 becomes the same as the document conveying speed with the scanning roller 26. In this case, the scanning roller 26 prevents the back face side of the document 1 from floating from the back face scan unit 25 by pressing the conveyed document 1 to the back face scan unit 25, and also serves as a white reference member for performing shading correction on the back face scan unit 25.
The discharging unit G includes the conveying guide 39, 43, a discharging sensor 24 provided in a proximity of the back face scan unit 25, a discharging roller 28 rotated and driven to discharge the document sheet to the stack unit H after the discharging sensor 24 detects the leading end of the document, and the discharge tray 29 on which the discharged document is placed.
As illustrated in
The document conveying device 52 of the present embodiment includes, as actuators and the like driven and controlled by the output signal from the controller 100, the back face scan unit 25, a pick-up ascending/descending motor 101, the sheet feeding motor 102, the scanning motor 103, the discharging motor 104, and the bottom plate ascending motor 105.
On the other hand, the image forming apparatus main body 51 of the digital MFP 50 having the document conveying device 52 of the present embodiment includes the main body control unit 111 for controlling the image forming apparatus main body 51, and an operating unit 108 with which a user performs various kinds of input operation and gives operation commands. The controller 100 and the main body control unit 111 are connected via the interface circuit 107, so that control signals, data, and the like are exchanged therebetween.
As illustrated in
Hereinafter, basic operation from when the document is placed on the document table 2 to when the document is discharged onto the discharge tray 29 and the control of the controller 100 will be explained in order.
First, the document 1 is placed on the document table 2 including the movable table 3 in such a manner that the front face of the document 1 is at the upper side, and the position of the document 1 in the width direction, i.e., the position in the direction perpendicular to the conveying direction is positioned by a side guide, not illustrated, and thus the document 1 is set.
The set detection feeler 4 and the document set sensor 5 detects that the document 1 is placed on the document table 2, and the detection signal is retrieved into the controller 100, and is also retrieved into the main body control unit 111 via the interface circuit 107. The document size of the document 1 on the document table 2 is detected by the size detection sensors 30 to 32 provided on the front face of the document table 2, and the document size is retrieved into the controller 100, and is also retrieved into the main body control unit 111.
When the document which is set on the document set unit A is thus detected, the controller 100 moves the bottom plate ascending motor 105 in the forward direction, and moves the movable table 3 upward so that the uppermost document sheet of the documents 1 on the document table 2 comes into contact with the pick-up roller 73.
At this occasion, the pick-up roller 73 comes into contact with the upper surface of the document 1 on the document table 2 with a contact pressure in accordance with its own weight from the pick-up bracket 72 to the pick-up roller 73. When the rotation given by the rotation driving shaft 71 is transmitted to the driving side pulley 75a via the toothed wheels 74a, 74b, and is transmitted from the driving side pulley 75a via the endless belt 76 to the driven side pulley 75b, the pick-up roller 73 rotates together with the driven side pulley 75b. Therefore, even when the upper face height of the document 1 on the document table 2 is changed, the contact pressure and the pick-up driving rotation speed of the pick-up roller 73 are maintained at preferable levels.
When the movable table 3 is driven to move upward, the pick-up roller 73 changes its level in the arrow direction in
Subsequently, when the operating unit 108 is manipulated to designate any one of duplex mode or single sided mode, and subsequently, a print key is pressed down, a document feeding signal is output from the main body control unit 111 via the interface circuit 107 to the controller 100.
At this occasion, the controller 100 rotates the sheet feeding motor 102 in the forward direction, whereby the pick-up roller 73 is rotated. The pick-up roller 73 having started its rotation picks up the uppermost document on the document table 2.
With the forward rotation of the sheet feeding motor 102, each of the paper feeding belt 95 and the reverse roller 96 is driven in the clockwise direction of
More specifically, while the reverse roller 96 is in direct contact with the paper feeding belt 95 or is in pressurized contact therewith with a document 1 interposed therebetween within the contact angle, the reverse roller 96 rotates in the counterclockwise direction which is different from the original driving direction due to a torque limiter, not illustrated, in accordance with the rotation of the paper feeding belt 95. However, when not only the uppermost document 1 but also an unnecessary subsequent document at the lower side thereof are picked up in an overlapping manner between the paper feeding belt 95 and the reverse roller 96, then, the reverse roller 96 rotates in the clockwise direction of
The document 1 separated by the action of the paper feeding belt 95 and the reverse roller 96 as described above (which may be hereinafter also referred to as separated document 1) is fed in the feeding direction by the paper feeding belt 95, and after the leading end thereof is detected by the document abutment sensor 11, the document 1 comes into abutment with the pull-out roller 12.
This abutment is such that while the separated document 1 is conveyed in the feeding direction by a predetermined distance from the position where it is detected by the document abutment sensor 11, the leading end side portion of the separated document 1 comes into abutment with the pull-out roller 12 with a predetermined amount of warping. Then, at this point in time, the sheet feeding motor 102 is stopped, and driving of the paper feeding belt 95 is stopped.
While the separated document 1 is conveyed by the paper feeding belt 95, the controller 100 raises the pick-up roller 73 from the upper face of the document 1 so as to be away therefrom using the pick-up ascending/descending motor 101 by means of the cam mechanism and pick-up bracket 72, not illustrated, and conveys the document using only the conveying force of the paper feeding belt 95. As a result, when the leading end of the document comes into abutment with the nip portion of the pull-out roller 12, the skew of the document is corrected.
Subsequently, the pull-out roller 12 and the intermediate roller 14 are driven in the backward direction by the sheet feeding motor 102, so that the skew-corrected document is conveyed to the intermediate roller 14. At this occasion, the pull-out roller 12 and the intermediate roller 14 are driven, but the pick-up roller 73 and the paper feeding belt 95, which are driven when the sheet feeding motor 102 moves in the forward direction, are in the non-driven state.
During the document conveying process to the intermediate roller 14, when the document passes the position where the multiple document width sensors 13 are installed, the controller 100 detects a difference of output levels between those shielded by the document 1 and those not shielded by the document 1 from among the multiple document width sensors 13 adjacent to each other in the document width direction, and the width direction size of the document conveyed by the pull-out roller 12 is detected, and the document size thereof is notified to the main body control unit 111.
The conveying state and the conveying direction length of the document 1 conveyed are detected by causing the document abutment sensor 11 to scan the leading end and the trailing end of the document 1 and counting the driving pulses of the conveying motor.
When the document is conveyed from the registration unit C to the turn unit D according to the driving of the pull-out roller 12 and the intermediate roller 14, the controller 100 configures the conveying speed such that the conveying speed at the registration unit C is set at a level higher than the conveying speed at the first scan conveying unit E, thus reducing the processing time required to feed the document into the first scan conveying unit E.
Operation from when the leading end of the conveyed document 1 is detected by the scanning entrance sensor 15 to when the scanning process starts is different according to whether the mode is non-stop mode or stop mode.
First, in the non-stop mode, the controller 100 starts reducing the document conveying speed in order to set the document conveying speed at the same level as the scanning conveying speed before the leading end of the document 1 enters into the nip portion of the scanning entrance roller 16, and thereafter uses the scanning entrance motor 114 to drive the scanning entrance roller 16, and further, uses the scanning motor 103 to drive each of the scanning roller 19, the scanning exit roller 23, and the CIS exit roller 27.
Subsequently, when the leading end of the document 1 is detected by the registration sensor 17, a gate signal indicating an effective image region in the sub-scanning direction of the front face is started to be transmitted from the controller 100 to the main body control unit 111 at a time when the leading end position of the document 1 detected by pulse-counting of the scanning motor 103 reaches the scanning position 20, and the gate signal is continuously transmitted until the trailing end position of the document 1 passes the scanning position 20
On the other hand, in the stop mode, after the leading end of the conveyed document 1 is detected by the scanning entrance sensor 15, the controller 100 stops the document 1 (registration stop) at a time when the document 1 comes into abutment into the nip portion of the scanning entrance roller 16 and a predetermined amount of warping occurs in the leading end portion of the document 1 (a time when a predetermined number of counted pulses is attained after the leading end is detected by the scanning entrance sensor 15), a registration stop signal is transmitted to the main body control unit 111 via the interface circuit 107. In this case, the position where the scanning entrance roller 16 is provided is a position where the document 1 once stops before the document 1 is begun to be scanned.
Subsequently, when the controller 100 receives a scanning start signal from the main body control unit 111, the controller 100 starts conveying the document 1 which is registered and stopped, and increases the conveying speed to attain a predetermined conveying speed so that the leading end position of the document 1 reaches the scanning position 20.
In this case, the time when the leading end of the conveyed document 1 reaches the scanning position 20 can be detected by counting the driving pulses of the scanning motor 103 from when the leading end of the conveyed document 1 is detected by the registration sensor 17.
Then, from when the leading end of the conveyed document 1 reaches the scanning position 20 to when the trailing end of the document 1 passes the scanning position 20, the gate signal indicating the effective image region of the front face in the sub-scanning direction is transmitted from the controller 100 to the main body control unit 111.
When the operation mode is a single sided mode, the controller 100 uses the scanning roller 19 and the scanning exit roller 23 to pass the document, which has passed the first scan conveying unit E, in a proximity of the back face scan unit 25 and the document reaches the CIS exit roller 27, and the document is conveyed to the discharging unit G. At this occasion, when the discharging sensor 24 detects the leading end of the document 1, the controller 100 rotates the discharging motor 104 in the forward direction to rotate the discharging roller 28 in the discharging direction (counterclockwise direction in
As described above, in the stop mode, when the scanning entrance sensor 15 detects the leading end of the document 1, the document 1 once stops at the scanning entrance roller 16, and in the non-stop mode, the document 1 is conveyed without being stopped temporarily.
When the operation mode is the duplex mode, the controller 100 counts the pulses of the scanning motor 103 since the leading end of the document 1 is detected by the discharging sensor 24, and outputs the gate signal indicating the effective image region in the sub-scanning direction to the back face scan unit 25 when the leading end of the document 1 reaches the scanning position of the back face scan unit 25. This gate signal is continuously output until the trailing end of the document 1 goes out of the document scanning position of the back face scan unit 25. When the trailing end of the document 1 goes out of the document scanning position of the back face scan unit 25, the controller 100 controls the driving speed of the discharging motor 104 so that the document 1 discharged onto the discharge tray 29 does not get out of the discharge tray 29.
Although the detailed hardware configuration of the controller 100 executing the control of document conveying operation as described above is not illustrated, the controller 100 includes a CPU, a ROM, a RAM, and an input/output interface circuit. In accordance with the control program stored in the ROM, when the feeding preparation operation is to be done, the controller 100 rotates the bottom plate ascending motor 105 in the forward direction, and raises the movable table 3 which is the bottom plate so that the uppermost surface of the document 1 on the document table 2 comes into contact with the pick-up roller 73, and when the feeding appropriate position sensor 8 attains the ON state, the controller 100 stops the upward movement of the movable table 3. Then, with the repetition of the feeding operation, the document upper face position is lowered, and when the feeding appropriate position sensor 8 is in the OFF state, the movable table 3 is raised so that the feeding appropriate position sensor 8 is in the ON state again. The controller 100 repeats this kind of bottom plate ascending control, thus maintaining the uppermost face position of the document 1 at a level appropriate for feeding at all times.
On the other hand, when the set documents on the document table 2 are all fed, and there is no longer any document 1 left on the document table 2, the controller 100 rotates the bottom plate ascending motor 105 in the backward direction as a sheet stacking preparation operation, and lowers the movable table 3 to the home position so that a subsequent document bundle can be set.
The controller 100 uses the pick-up ascending/descending motor 101 with the cam mechanism and the pick-up bracket 72 to raise the pick-up roller 73 to a different height position, and changes the level in c, d directions indicated by the arrow in
Further, when the document 1 is conveyed from the registration unit C to the turn unit D according to the driving of the pull-out roller 12 and the intermediate roller 14, the controller 100 configures the conveying speed such that the conveying speed at the registration unit C is set at a level higher than the conveying speed at the first scan conveying unit E, thus reducing the time required to convey the document 1 to the scanning unit.
The sensor chip 201 is provided with a contact-type image sensor constituted by an photoelectric conversion element and a condensing lens and the like. Before a document, not illustrated, enters into the scanning position with the back face scan unit 25, the controller 100 transmits an illumination ON signal to the light source unit 200. Accordingly, the light source unit 200 is turned on, and the light is emitted onto the second face of the document, not illustrated. With the multiple sensor chips 201, the reflected light reflected by the second face of the document is condensed by the condensing lens onto the photoelectric conversion element, and is scanned as image information. The image information scanned by each sensor chip 201 is amplified by the operational amplifier circuit 202, and thereafter converted into digital image information by the A/D converter 203. The digital image information is input into the image processing unit 204 to be subjected to the shading correction and the like, and thereafter it is stored to the frame memory 205 temporarily. Thereafter, it is converted by the output control circuit 206 into a data format that can be received by the main body control unit 111, and thereafter, it is output via the interface circuit 107 to the main body control unit 111. The controller 100 output an operational timing signal for notifying a time when the leading end of the document reaches the scanning position with the back face scan unit 25 (image data after this point in time will be treated as effective data), an illumination signal for the light source, a power supply, and the like.
Subsequently, detailed configuration of the separation sheet feeding mechanism related to the features of the present invention will be explained.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
This separation pressure adjustment mechanism 60 includes a cam member 61 including a first cam face 61a and a second cam face 61b facing each other in the rotation radius direction, a cam driving unit 62 (cam driving source) capable of rotating the cam member 61 and maintaining it at the rotation angle position, and a paper feeding belt holder bracket 92 serving as a cam follower member for changing the relative position of the paper feeding belt 95 and the reverse roller 96 in accordance with the rotation angle position of the cam member 61.
More specifically, as illustrated in
As illustrated in
More specifically, the first cam face 61a and the second cam face 61b respectively are formed in parallel with the rotation central axis of the cam member 61, and are parallel to each other. The rotation radius of the first cam face 61a according to the rotation angle position of the cam member 61 is less than the rotation radius of the second cam face 61b according to the rotation angle position of the cam member 61.
Further, when the protruding pin 92e of the paper feeding belt holder bracket 92 moves along the first cam face 61a, the second cam face 61b of the cam member 61 is formed along a virtual envelope always in contact with the protruding pin 92e of the paper feeding belt holder bracket 92 from the opposite side to the first cam face 61a in the rotation radius direction of the cam member 61. When the protruding pin 92e of the paper feeding belt holder bracket 92 of which leading end side is in a circular cross section moves relatively along the first cam face 61a according to the rotation of the cam member 61, the second cam face 61b is restricted within a guide clearance range which previously sets floating of the protruding pin 92e of the paper feeding belt holder bracket 92 from the first cam face 61a (floating of the cam member 61 in the rotation radius direction).
More specifically, when the cam member 61 rotates, the first cam face 61a and the second cam face 61b of the cam member 61 restricts the displacement of the protruding pin 92e in the rotation radius direction of the cam member 61 within the guide clearance range, and at the same time allows positioning at the lift position corresponding to such cam profile and rotation angle position.
As illustrated in
More specifically, as illustrated in
As illustrated by a virtual line (chain double-dashed line) in
In the present embodiment, the lift of the first cam face 61a of the cam member 61 changes on every 90-degree rotation, and the contact angle of the nip portion of the paper feeding belt 95 with respect to the separation pressure and the reverse roller 96 can be switched to three levels, but it is to be understood that a different number of steps for switching and a different lift interval may be set.
As illustrated in
In this case, the inclination feeler 66 can be seen from the outside of the sheet feeding unit 300 through an opening portion 64a of the support bracket 64, and changes the inclination posture in accordance with the change of the rotation angle of the cam driving unit 62, and enters into or retracts from the opening portion 64a of the support bracket 64 in accordance with the rotation angle position of the cam driving shaft 63. The cam angle position sensor 67 is constituted by a switch changing the ON/OFF state in accordance with the inclination feeler 66 returned back to the home position, and is provided within the sheet feeding unit 300. The cam driving motor 68 is supported by one end side of the frame 30 of the sheet feeding unit 300 in the longitudinal direction, and can transmit rotation motion to the motion transmission toothed wheel 65 via a motion transmission path, not illustrated. It should be noted that the sheet feeding motor 102 is supported by the other end side of the frame 320 of the sheet feeding unit 300 in the longitudinal direction, which is opposite to the cam driving motor 68.
The support bracket 64 is fixed with a fixing screw 69 to the frame 320 of the sheet feeding unit 300, but when the fixing screw 69 is removed, the support bracket 64 can be moved in the axial direction of the cam driving shaft 63 with respect to the frame 320, or, it can be detached from the frame 320.
More specifically, as illustrated in
When the cam driving unit 62 is moved away from the paper feeding belt holder bracket 92 of the separation sheet feeding mechanism 9, the pick-up mechanism 7 and the separation sheet feeding mechanism 9 integrally coupled with the rotation driving shaft 71 can be detached from the frame 320 of the sheet feeding unit 300 as follows. By cancelling the connection state between a coupling 71c at the right end portion in
In the sheet feeding unit 300, as described above, when the support bracket 64 is moved with respect to the frame 320 so as to move the cam driving unit 62 away from the paper feeding belt holder bracket 92, the restriction state can be cancelled. In the restriction state, the protruding pin 92e of the paper feeding belt holder bracket 92 is positioned at the lift position in accordance with the rotation angle position from both sides in the rotation radius direction of the cam member 61 with the first cam face 61a and the second cam face 61b.
The cam member 61 can move in the rotation center axial direction of the cam member 61 with respect to the protruding pin 92e of the paper feeding belt holder bracket 92, and can move between a contact position as illustrated in
A cylindrical roller 92f is attached to the protruding pin 92e of the paper feeding belt holder bracket 92 so as to reduce the frictional force during sliding with the separation pressure adjustment mechanism 60. This cylindrical roller 92f is configured to freely rotate regardless of the rotation of the cam member 61 for separation pressure adjustment, and the sliding resistance can be reduced during rotation of the cam member 61. In the present embodiment, the cylindrical roller 92f is provided, but when a material having a superior sliding property is selected for the protruding pin 92e, the protruding pin 92e may be a simple round stick-shaped pin.
Subsequently, an operation will be explained.
In the digital MFP 50 of the present embodiment as configured above, when the cam member 61 rotates, the protruding pin 92e sandwiched between the first cam face 61a and the second cam face 61b is restricted from freely moving in the rotation radius direction by the two cam faces 61a, 61b, and when the cam member 61 rotates in that state, the contact angle of the nip portion of the paper feeding belt 95 with respect to the reverse roller 96 is gradually changed.
More specifically, as illustrated in
In order to find the rotation angle position of the cam member 61, the inclination feeler 66 is attached to the cam driving shaft 63, and the inclination feeler 66 and the cam angle position sensor 67 are provided within the sheet feeding unit 300, and therefore, the position at the start of rotation of the cam member 61 can be detected, and it can be returned back to the home position. Therefore, when a stepping motor and the like is used for the cam driving motor 68, the initial position of the cam member 61 and the rotation angle therefrom can be controlled using the driving pulse of the stepping motor, and the cam member 61 can be controlled to be at an appropriate lift position. As a result, the cam member 61 can be stopped at an appropriate rotation angle position, and the contact angle of the nip portion of the paper feeding belt 95 with respect to the reverse roller 96 can be appropriately adjusted.
Further, the cam member 61 can move in the rotation center axial direction of the cam member 61 with respect to the protruding pin 92e of the paper feeding belt holder bracket 92, and can move between a contact position where the cam member 61 is in contact with the protruding pin 92e of the paper feeding belt holder bracket 92 and a separation position where the cam member 61 is away from the protruding pin 92e of the paper feeding belt holder bracket 92, and therefore, it is easy to separate and reconnect the cam member 61 and the paper feeding belt holder bracket 92, and this makes it easy to maintain the separation sheet feeding mechanism 9 including the paper feeding belt 95 and the separation pressure adjustment mechanism 60, and further, to maintain the pick-up mechanism 7
As illustrated in
Even if the thickness of a sheet which is to be passed is not appropriate or the driving load of the sheet feeding motor 102 is not appropriate for the contact angle of the nip portion and the separation pressure of the paper feeding belt 95 and the reverse roller 96 which are set in advance, abrupt change of the contact angle of the nip portion of the paper feeding belt 95 and the reverse roller 96 can be effectively prevented during the document conveying process. The cam member 61 is configured such that the lift position of the protruding pin 92e of the paper feeding belt holder bracket 92 can be switched in multiple steps, and the appropriate rotation angle position can be set, and therefore, the contact angle of the nip portion of the paper feeding belt 95 and the reverse roller 96 and the separation pressure corresponding thereto can be easily switched to appropriate contact angle and separation pressure.
In addition, in the present embodiment, each of the lifts L1, L2, L3 can be maintained at a certain level within the angle ranges of the four separation pressure maintaining sections Z1 to Z4 of the first cam face 61a, and therefore, even if the rotation angle position of the cam member 61 and the cam driving shaft 63 are abruptly changed, the application point of the paper feeding belt holder bracket 92 is not changed. Therefore, it is not necessary to strictly suppress the error of the stop position of the cam member 61, and while the component processing cost of the cam driving system from the cam driving motor 68 to the cam member 61 is reduced, the lift position of the protruding pin 92e can be appropriately maintained, and the contact angle and separation pressure can be controlled in a preferable manner.
As illustrated by the virtual line in
Further, for example, when a user is allowed to select the feeding condition on the screen of the operating unit 108 in such a manner that the user selects any one of multiple conditions such as setting 1, setting 2, and the like, the separation pressure can be set without complicated operation in accordance with the any given thickness of the sheet. This selection operation may be done using, for example, a selection button, and the setting value may be set according to the type of sheet such as plain paper, thick paper, coated paper, or may be set according to the type of sheet such as slippery paper, smooth paper, and the like.
When the configuration is made such that, even if the document stops due to failure in the document conveying process, the cam member 61 is rotated to sufficiently reduce or eliminate the contact pressure of the paper feeding belt 95 and the reverse roller 96, then, this can prevent excessive load from being applied to the clogged document sheet, and the damage to the document can be eliminated.
The cam driving unit 62 made into the unit can be easily detached from or slid with respect to the frame 320 of the sheet feeding unit 300, and it can be moved away from the paper feeding belt holder bracket 92 of the separation sheet feeding mechanism 9 and the paper feeding belt 95, and therefore, the maintenance work space for the paper feeding belt 95 and the reverse roller 96 can be easily ensured. In addition, the pick-up mechanism 7 and the separation sheet feeding mechanism 9 which are integrally made into the unit with the rotation driving shaft 71 can be easily detached from the frame 320 of the sheet feeding unit 300, and therefore, with regard to this point, the maintenance can also be simplified.
When the separation sheet feeding mechanism 9 is detached from the sheet feeding unit 300 during the maintenance, the reverse roller 96 can be seen easily, and this makes it easy to do replacement and the like. When the sheet feeding unit 300 is detached from the main frame of the document conveying device 52, the reverse roller 96 can be easily seen from the outside of the sheet feeding unit 300, and the maintenance work can be done easily. The separation sheet feeding mechanism 9 made into a detachable unit as the sheet feeding unit 300 can be handled in an extremely easy manner.
As described above, in the present embodiment, very small movement of the protruding pin 92e of the paper feeding belt holder bracket 92 during the separation sheet feeding operation is suppressed by the first cam face 61a and second cam face 61b of the cam member 61. Therefore, while the sheet conveying device employs the configuration of capable of changing the separation pressure by adjusting the contact angle at the nip portion of the paper feeding belt 95 and the reverse roller 96 with the relative displacement of the cam member 61 and the paper feeding belt holder bracket 92, the sheet conveying device can maintain appropriate contact angle during the separation sheet feeding operation, and can obtain the optimum separation pressure at all times.
In the present embodiment, the intervals in the rotation radius direction of the first cam face 61a and the second cam face 61b at multiple rotation angle positions of the cam member 61 are substantially the same interval, and therefore, when the protruding pin 92e of the paper feeding belt holder bracket 92 moves relatively along the first cam face 61a according to the rotation of the cam member 61, the floating of the protruding pin 92e from the first cam face 61a can be limited to the guide clearance range which has been set in advance.
Further, in the present embodiment, the protruding pin 92e of the paper feeding belt holder bracket 92 is inserted into the circular cam groove portion 61c of the cam member 61 so that it is positioned between the first cam face 61a and the second cam face 61b in the rotation radius direction, and therefore, very small movement of the protruding pin 92e of the paper feeding belt holder bracket 92 can be appropriately suppressed by the first and second cam faces of the cam member 61 during the separation sheet feeding operation.
In addition, the protruding pin 92e of the paper feeding belt holder bracket 92 is the protruding unit provided to protrude to the cam member 61 from the paper feeding belt holder bracket 92 holding the paper feeding belt 95 so as to allow feeding operation, and the protruding pin 92e is inserted between the first cam face 61a and the second cam face 61b of the cam member 61, and therefore, very small movement of the protruding pin 92e of the paper feeding belt holder bracket 92 can be appropriately suppressed by the first cam face 61a and second cam face 61b of the cam member 61 during the separation sheet feeding operation.
In the digital MFP 50 of the present embodiment, using the relative displacement of the cam member 61 and the paper feeding belt holder bracket 92, the contact angle of the nip portion of the paper feeding belt 95 and the reverse roller 96 is adjusted to change the separation pressure, and in addition, very small movement of the protruding pin 92e of the paper feeding belt holder bracket 92 can be suppressed by the first cam face 61a and second cam face 61b of the cam member 61 during the separation sheet feeding operation. Therefore, the image forming apparatus can maintain the contact angle of the nit portion of the paper feeding belt 95 and the reverse roller 96 at an appropriate level during the separation sheet feeding operation, and the document 1 which is to be fed with the optimum separation pressure at all times and can convey appropriately the document 1 to the document image scanning position, thus having superior document conveying performance.
In the above embodiment, the first cam face 61a and the second cam face 61b have tube-like surfaces parallel to each other having lines as generating lines. Alternatively, the first cam face may have stepped cam face shape, in which the lifts are different according to the axial direction positions, or the generating line may be bent gently. When the contact unit is in a stepped shape, a shaft bearing element allowing slipping in the rotation direction just like the cylindrical roller 92f may be interposed between the first contact unit in contact with the first cam face and the second contact unit in contact with the second cam face.
The cam member of the present embodiment may be made of a single member such as the cam member 61. Alternatively, it may include first and second cam members (multiple cam members) arranged on the same rotation center axis.
As explained above, the present invention, during the separation sheet feeding operation, very small movement of the contact unit of the cam follower member can be effectively suppressed from both sides in the rotation radius direction of the cam member using the first and second cam faces. Therefore, the sheet conveying device and the image forming apparatus can be provided, which employs the configuration of changing the separation performance by adjusting the nip portion of the contact angle of the paper feeding belt and the separation roller with the relative displacement of the cam member and the cam follower member, but capable of obtaining preferable separation performance at all times by maintaining preferable contact angle during the separation sheet feeding operation thereof. The present invention as described above is useful for sheet conveying devices and image forming apparatuses using them in general which are suitable for document conveying devices for conveying document sheets to a image scanning position.
According to the present invention, the contact unit of the cam follower member is guided by the cam member of the adjustment mechanism to the lift position in accordance with the rotation angle position of the cam member from both sides in the rotation radius direction of the cam member, and therefore, during the separation sheet feeding operation, very small movement of the contact unit of the cam follower member can be effectively suppressed from both sides in the rotation radius direction of the cam member using the first and second cam faces. As a result, the sheet conveying device and the image forming apparatus can be provided such that even though the sheet conveying device and the image forming apparatus employs the configuration for changing the separation performance by adjusting the contact angle of the nip portion of the paper feeding belt and the separation roller by relative displacement of the cam member and the cam follower member, the contact angle is preferably maintained during the separation sheet feeding operation, and the optimum separation performance can be obtained at all times. The cam member as referred to in the present embodiment may be a single member or multiple cam members arranged on the same rotation center axis.
When the contact unit of the cam follower member relatively moves along the first cam face in accordance with the rotation of the cam member, the second cam face limits the floating of the control unit from the first cam face to a clearance range which has been set in advance. It should be noted that the second cam face is preferably formed such that, when the contact unit moves along the first cam face, the second cam face is formed along an envelope always in contact with the contact unit from the opposite side to the first cam face in the rotation radius direction.
Very small change of the contact unit of the cam follower member can be appropriately suppressed by the first and second cam faces of the cam member during the separation sheet feeding operation. It should be noted that the rotation radius of the first cam face according to the rotation angle position of the cam member is less than the rotation radius of the second cam face according to the rotation angle position of the cam member, and the first cam face and the second cam face are more preferably formed in parallel with the rotation center axis of the cam member.
Very small change of the contact unit of the cam follower member can be appropriately suppressed by the first and second cam faces of the cam member during the separation sheet feeding operation.
Change of the rotation angle position of the cam member with respect to the contact unit of the cam follower member can be effectively suppressed by the concaved cam face portion, and the separation performance of the separation roller is preferably maintained.
Even if the rotation angle position of the cam member is changed with respect to the contact unit of the cam follower member, the lift of the contact unit on the first cam face can be maintained at a certain level, and the separation performance of the separation roller is preferably maintained. More specifically, even if the shaft driving the cam member rotates relatively with respect to the contact unit, the application point of the force in the rotation radius direction and the lift of the cam member with respect to the contact unit of the cam follower member are not changed substantially.
The adjustment mechanism provided at one side of the paper feeding belt can be easily detached from the separation sheet feeding driving source, and it is easy arrange the adjustment mechanism and ensure the work space therefor.
The cam member and the cam follower member can be detached and reconnected easily, and this makes it easy to maintain the paper feeding belt and the adjustment mechanism.
The separation sheet feeding mechanism made into a detachable unit can be handled in an extremely easy manner.
Even though the image forming apparatus of the present invention having the above configuration employs the configuration for changing the separation performance by adjusting the contact angle of the nip portion of the paper feeding belt and the separation roller by relative displacement of the cam member and the cam follower member, very small change of the contact unit of the cam follower member can be suppressed by the first and second cam faces of the cam member of the adjustment mechanism during the separation sheet feeding operation. Therefore, the image forming apparatus is such that the contact angle of the nip portion of the paper feeding belt and the separation roller can be maintained in a preferable manner during the separation sheet feeding operation, and the document which is to be fed can appropriately conveyed to the document image scanning position with the optimum separation pressure at all times, and thus, the image forming apparatus has superior document conveying performance.
Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-212650 | Sep 2012 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4523832 | Strutt et al. | Jun 1985 | A |
| 20020195766 | Sekine | Dec 2002 | A1 |
| 20070264063 | Sano et al. | Nov 2007 | A1 |
| 20070278734 | Yoshida | Dec 2007 | A1 |
| 20080308995 | Tobinaga et al. | Dec 2008 | A1 |
| 20100027081 | Sano et al. | Feb 2010 | A1 |
| 20100225045 | Kimura et al. | Sep 2010 | A1 |
| 20100225983 | Fujii et al. | Sep 2010 | A1 |
| 20110304092 | Kambayashi et al. | Dec 2011 | A1 |
| 20120002252 | Kubo et al. | Jan 2012 | A1 |
| 20120057212 | Tobinaga et al. | Mar 2012 | A1 |
| 20120119432 | Kambayashi et al. | May 2012 | A1 |
| 20120119436 | Morita et al. | May 2012 | A1 |
| 20120236375 | Fujita et al. | Sep 2012 | A1 |
| 20120314267 | Suzuki et al. | Dec 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 2002-347960 | Dec 2002 | JP |
| Entry |
|---|
| U.S. Appl. No. 13/768,270, filed Feb. 15, 2013. |
| Number | Date | Country | |
|---|---|---|---|
| 20140084531 A1 | Mar 2014 | US |
