Patent Grant
8950747
This nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application Nos. 2011-233013 and 2011-275806 filed in Japan on Oct. 24, 2011 and Dec. 16, 2011, respectively, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus and, more specifically, to a recording paper conveying device, a document feeding device and an image forming apparatus provided with these devices, preventing unnecessary deflection of recording paper in front of a registration roller pair and thereby enabling reduction in size of products.
2. Description of the Background Art
In an image forming apparatus such as a copying machine, a sheet of recording paper is drawn out from a paper feed tray and fed to an image forming unit, and an image is formed (printed) on a surface of the recording paper. By way of example, if electrophotography is utilized, a toner image carried on a photoreceptor drum or on a transfer body is transferred to a fed sheet of recording paper to obtain an image. The sheet of recording paper is drawn out from the paper feed tray by means of a roller, pinched by opposing rollers arranged along a paper feed path, and fed by the rotation of rollers. When a sheet of recording paper is drawn out from the paper feed tray, leading edge of the sheet may possibly be drawn out not in an orientation perpendicular to the drawing direction, but rotated to some extent. During feeding of the recording paper, it is also possible that the sheet is conveyed with its leading edge not kept perpendicular to the feeding direction. If the sheet of recording paper is fed askew to the transfer unit, an image will be formed askew with respect to the longitudinal or lateral side of the recording paper.
Similar problem may occur when a document is fed to a scanning position using an automatic document feeder (ADF) in an image forming apparatus. If the document is fed askew, the document will be scanned askew.
Therefore, conventionally, skew correction of recording paper is done immediately preceding a registration roller pair (upstream side in the paper feed direction) for supplying the recording paper to the transfer unit. Specifically, a conveyor roller pair (in the following, also referred to as a pre-registration roller pair) arranged immediately preceding the registration roller pair feeds a sheet of recording paper to the registration roller pair of which rotation is suspended, leading edge of the sheet is brought into contact with or abuts the registration roller pair so that the sheet is deflected, and then rotation of the registration roller pair is started, to convey the sheet of recording paper. By way of example, the velocities of registration roller pair and pre-registration roller pair are controlled as shown in
As a solution to this problem, Japanese Patent Laying-Open No. 2010-111472 (hereinafter referred to as '472 Reference) discloses a technique of deflecting a sheet (of recording paper) by a prescribed amount by the rotation of pre-registration roller pair, and thereafter accelerating the registration roller pair and the pre-registration roller pair simultaneously and at the same rate of acceleration to attain a constant velocity, as shown in
In '472 Reference, however, the velocity of rotation of pre-registration roller pair to cause the prescribed amount of deflection is a low velocity (100 mm/s) that corresponds to a self-start frequency at which a stepping motor driving the pre-registration roller pair can start rotation, and the pre-registration roller pair is once stopped. Therefore, it takes time to form an image on the sheet of recording paper, and performance of the image forming apparatus cannot be much enhanced. This poses a significant problem in a high-speed apparatus.
In view of the problems described above, it is desirable to provide a recording paper conveying device, a document feeding device and an image forming apparatus provided with these devices, all reduced in size, capable of preventing unnecessary deflection of recording paper or document immediately in front of the registration roller pair, and thereby reducing the space for holding the recording paper or document deflected in an appropriate shape, while not compromising their performances.
According to a first aspect, the present invention provides a recording paper conveying device, including a registration roller pair and a conveyor roller pair arranged adjacent to the registration roller pair on an upstream side of a recording paper feeding direction. The recording paper conveying device is for conveying a sheet of recording paper by rotating the conveyor roller pair, to have a leading edge of the sheet of recording paper abut the registration roller pair in a stationary state, and thereby causing the sheet of recording paper to deflect by a prescribed amount. In the recording paper conveying device, the registration roller pair is rotated with the conveyor roller pair kept rotating and the sheet of recording paper kept deflected, so as to start feeding of the sheet of recording paper by the registration roller pair, and while the registration roller pair is kept rotating, rotation of the conveyor roller pair is suspended for a prescribed time period and thereafter restarted, or decelerated for a prescribed time period and thereafter accelerated.
Preferably, rotation of the conveyor roller pair is suspended or decelerated while the registration roller pair is rotating with acceleration.
More preferably, in the recording paper conveying device, while the registration roller pair is rotating, rotation of the conveyor roller pair is suspended for the prescribed time period and thereafter restarted to resume a state of rotation before suspension, or decelerated for the prescribed time period and thereafter accelerated to resume a state of rotation before deceleration.
More preferably, velocity of rotation of the conveyor roller pair when the registration roller pair is rotated with the sheet of recording paper kept deflected is a constant velocity; the state before suspension or the state before deceleration is a state in which the velocity of rotation is the constant velocity; and the registration roller pair rotated with the sheet of recording paper kept deflected is accelerated until velocity of rotation attains to the constant velocity.
More preferably, the recording paper conveying device further includes: a first driving device for rotating the registration roller pair; and a second driving device different from the first driving device, for rotating the conveyor roller pair.
More preferably, the first and second driving devices are stepping motors. The recording paper conveying device further includes a driver unit for supplying pulse signals of a prescribed sequence for controlling the stepping motor to each of the first and second driving devices. The driver unit supplies, to the second driving device, pulse signals of a sequence causing rotation of the second driving device to be suspended or to be decelerated for a prescribed time period and thereafter to resume the state of rotation before suspension or deceleration, while supplying, to the first driving device, pulse signals of a sequence causing the first driving device to rotate.
Preferably, the recording paper conveying device further includes: a driving device; a first clutch for connecting the registration roller pair to the driving device; and a second clutch for connecting the conveyor roller pair to the driving device; and the driving device rotates the registration roller pair through the first clutch, and rotates the conveyor roller pair through the second clutch.
According to a second aspect, the present invention provides a document feeding device, including a registration roller pair and a conveyor roller arranged adjacent to the registration roller pair on an upstream side of a document feeding direction. The document feeding device is for feeding a document by rotating the conveyor roller, to have a leading edge of the document abut the registration roller pair in a stationary state, and thereby causing the document to deflect by a prescribed amount. In the document feeding device, the registration roller pair is rotated with the conveyor roller kept rotating and the document kept deflected, so as to start feeding of the document by the registration roller pair; and while the registration roller pair is kept rotating, rotation of the conveyor roller is suspended or decelerated for a prescribed time period and thereafter the conveyor roller is returned to the state of rotation before suspension or deceleration.
According to a third aspect, the present invention provides an image forming apparatus including at least one of the recording paper conveying device in accordance with the first aspect and the document feeding device in accordance with the second aspect.
According to a fourth aspect, the present invention provides a recording paper conveying device, including a registration roller pair and a conveyor roller pair arranged adjacent to the registration roller pair on an upstream side of a recording paper feeding direction. The recording paper conveying device is for conveying a sheet of recording paper by rotating the conveyor roller pair, to have a leading edge of the sheet of recording paper abut the registration roller pair in a stationary state, and thereby causing the sheet of recording paper to deflect by a prescribed amount. In the recording paper conveying device, the conveyor roller pair is rotated at a constant velocity to cause said deflection of the sheet of recording paper; the registration roller pair is rotated to start feeding of the sheet of recording paper by the registration roller pair, with the sheet of recording paper kept deflected and the conveyor roller pair kept rotating at the constant velocity; and when velocity of rotation of the registration roller pair reaches a prescribed velocity, rotation of the conveyor roller pair is further accelerated from the constant velocity.
Preferably, in the recording paper conveying device, the conveyor roller pair is rotated to feed the sheet of recording paper until a leading edge of the sheet of recording paper reaches a position near the registration roller pair in a stationary state, rotation of the conveyor roller pair is suspended at this time point, and thereafter the conveyor roller pair is rotated with acceleration to cause the deflection of the sheet of recording paper.
More preferably, in the recording paper conveying device, after starting feeding of the sheet of recording paper by the registration roller pair by rotating the registration roller pair, rotation of the registration roller pair is accelerated.
More preferably, in the recording paper conveying device, the conveyor roller pair in a stationary state is rotated with acceleration at a constant rate of acceleration and thereafter rotated at the constant velocity. The rate of acceleration for further accelerating rotation of the conveyor roller pair from the constant velocity and the rate of acceleration for accelerating rotation of the registration roller pair are the same as the constant rate of acceleration.
Preferably, the timing of further accelerating rotation of the conveyor roller pair from the constant velocity is when velocity of rotation of the registration roller pair becomes equal to the constant velocity.
More preferably, the recording paper conveying device further includes: a first driving device for rotating the registration roller pair; and a second driving device different from the first driving device, for rotating the conveyor roller pair.
More preferably, the first and second driving devices are stepping motors, and the recording paper conveying device further includes a driver unit for supplying pulse signals of a prescribed sequence for controlling the stepping motor to each of the first and second driving devices. The driver unit supplies pulse signals of a first sequence to cause the conveyor roller pair to rotate at the constant velocity to the first driving device to cause the deflection of the recording paper, supplies pulse signals of a second sequence to cause the registration roller pair to rotate to the second driving device, while the pulse signals of the first sequence are supplied to the first driving device, and when velocity of rotation of the registration roller pair reaches a prescribed velocity, supplies pulse signals of a third sequence to further accelerate rotation of the conveyor roller pair from the constant velocity, to the first driving device.
Preferably, the recording paper conveying device further includes: a driving device; a first clutch for connecting the registration roller pair to the driving device; and a second clutch for connecting the conveyor roller pair to the driving device. The driving device rotates the registration roller pair through the first clutch, and rotates the conveyor roller pair through the second clutch.
According to a fifth aspect, the present invention provides a document feeding device, including a registration roller pair and a conveyor roller arranged adjacent to the registration roller pair on an upstream side of a document feeding direction. The document feeding device is for feeding a document by rotating the conveyor roller, to have a leading edge of the document abut the registration roller pair in a stationary state, and thereby causing the document to deflect by a prescribed amount. In the document feeding device, the conveyor roller is rotated at a constant velocity to cause the deflection of the document; the registration roller pair is rotated to start feeding of the document by the registration roller pair, with the sheet kept deflected and the conveyor roller kept rotating at the constant velocity; and when velocity of rotation of the registration roller pair reaches a prescribed velocity, rotation of the conveyor roller is further accelerated from the constant velocity.
According to a sixth aspect, the present invention provides an image forming apparatus including at least one of the recording paper conveying device in accordance with the fourth aspect and the document feeding device in accordance with the fifth aspect.
By the present invention, it becomes possible to maintain an appropriate deflection, without causing unnecessary deflection of the sheet of recording paper exceeding the necessary amount for correcting any skew of the recording paper or document, immediately in front of the registration roller pair. Therefore, the space for holding the recording paper or document deflected appropriately without causing buckling between the registration roller pair and the pre-registration roller pair can be made smaller. As a result, the recording paper conveying device, the document feeding device and the image forming apparatus using these devices can be reduced in size.
Further, the present invention does not lower the performance of feeding the recording paper or document.
Further, by the present invention, it is possible to set the constant velocity of conveyor roller pair to a value close to the process velocity of image formation or a value not much slower than the process velocity. Therefore, a high-speed recording paper conveying device and the image forming apparatus using the same can be reduced in size.
Further, by the present invention, it is possible to set the constant velocity of conveyor roller pair to a value close to the process velocity of document scanning or a value not much slower than the process velocity. Therefore, a high-speed document feeding device and the image forming apparatus using the same can be reduced in size.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
In the following embodiments, the same components are denoted by the same reference characters. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
Referring to
At an upper portion of main body 110, image reading device 90 provided with a platen 92 of transparent glass for placing a document is arranged, and automatic document feeder 120 is attached above platen 92. Automatic document feeder 120 is formed to be rotatable in the direction of an arrow M, so that when opened, one can manually place the document on platen 92.
The image data handled in the present image forming apparatus 100 are color image data using colors of black (K), cyan (C), magenta (M) and yellow (Y), that is, image data separated to components of these four colors. Therefore, in order to form four different latent images of respective colors, four developers 2, four photoreceptor drums 3, four chargers 5 and four cleaner units 4 are provided.
Charger 5 is a device for uniformly charging the surface of photoreceptor drum 3 to a prescribed potential.
Optical scanning device 1 is a laser scanning unit (LSU) including a laser emitting unit and a reflection mirror.
Optical scanning device 1 exposes the charged photoreceptor drum 3 in accordance with the input image data, and thereby forms an electrostatic latent image in accordance with the image data on the surface. Developer 2 turns the electrostatic latent images formed on respective photoreceptor drums 3 to visible images with toners of four colors (YMCK), respectively. Cleaner unit 4 removes and recovers the toner left on the surface of each photoreceptor drum 3, after development and image transfer.
Intermediate transfer belt unit 6 arranged above photoreceptor drum 3 includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer roller 64 and an intermediate transfer belt cleaning unit 65.
Around intermediate transfer belt driving roller 62, intermediate transfer belt driven roller 63, and intermediate transfer roller 64, intermediate transfer belt 61 is wound and driven to rotate.
By successively transferring the toner images of respective colors formed on photoreceptor drums 3 onto intermediate transfer belt 61 to be superposed on the last, a color toner image (multi-color toner image) is formed on intermediate transfer belt 61.
Transfer of the toner image from photoreceptor drum 3 to intermediate transfer belt 61 is done by intermediate transfer roller 64 that is in contact with the back side of intermediate transfer belt 61. A high voltage transfer bias is applied to intermediate transfer roller 64, in order to transfer the toner image.
Information of the superposed images (density distribution of toner) on intermediate transfer belt 61 is transferred to a sheet of recording paper, as intermediate transfer belt 61 is rotated, by a transfer roller 10 arranged at the position of contact between the intermediate transfer belt 61 and the sheet of recording paper.
At this time, intermediate transfer belt 61 and transfer roller 10 are brought in to pressure-contact with a prescribed nip, and a voltage for transferring the toner to the sheet of recording paper is applied to transfer roller 10.
The toner left on intermediate transfer belt 61 are removed and recovered by intermediate transfer belt cleaning unit 65.
Paper feed cassette 81 is a tray for storing sheets of recording paper to be used for image formation, and provided below optical scanning device 1 in main body 110. Sheets of recording paper may also be placed on a manual feed cassette 82. A paper discharge tray 91 provided on main body 110 is for collecting the printed sheets of paper in face-down manner, that is, with the printed surface facing downward.
In main body 110, a paper feeding path S is formed in a substantially vertical direction, for feeding sheets of recording paper in paper feed cassette 81 or manual feed cassette 82 to paper discharge tray 91 through transfer roller 10 and fixing unit 7.
Conveyor roller pairs 12a to 12e are small rollers for promoting and assisting feeding of the recording paper, and a plurality of conveyor roller pairs are provided along paper feeding path S.
Registration roller pair 13 temporarily holds the sheet of recording paper fed along paper feeding path S. Then registration roller pair 13 feeds the sheet of recording paper to transfer roller 10 at such timing when the leading edge of toner image on photoreceptor drum 3 is aligned with the leading edge of the sheet of recording paper.
Fixing unit 7 includes a heat roller 71 and a pressure roller 72. Heat roller 71 and pressure roller 72 rotate, with the sheet of recording paper pinched therebetween. Heat roller 71 presses with heat, together with pressure roller 72, the toner to the sheet of recording paper, and thus, it has a function of melting, mixing and causing pressure-contact of multi-color toner image that has been transferred to the sheet of recording paper and thereby heat-fixing the image on the sheet of recording paper. Further, an external heating belt 73 for heating heat roller 71 from outside is provided in fixing unit 7.
The path for feeding the sheet of recording paper will be specifically described. In order to feed sheets of paper from these paper cassettes 81 and 82, pick-up rollers 11a and 11b are arranged, respectively, to guide the sheets of recording paper one by one to paper feeding path S.
A sheet of recording paper coming from paper feed cassette 81 or 82 is conveyed to registration roller pair 13 by conveyor roller pairs 12a and 12e along paper feeding path S, fed to transfer roller 10 at the timing when the leading edge of the sheet and the leading edge of image information are aligned, and thus, image information is written on the sheet of recording paper. Thereafter, not-yet fixed toner on the sheet of recording paper is melted and fixed as the sheet passes through fixing unit 7, and through conveyor roller pair 12b arranged at the end of paper feeding path S, the sheet is discharged to discharge tray 91.
If double-sided printing is requested, when the rear end of the sheet that has passed the fixing unit 7 is held by the conveyor roller pair 12b at the end of the feeding path, the conveyor roller pair 12b rotates in reverse direction. Thus, the sheet of recording paper is fed to conveyor roller pairs 12c and 12d. Thereafter, the sheet of recording paper is fed to registration roller pair 13, printing is done on the back side of the sheet in the same manner as described above, and then the sheet is discharged to paper discharge tray 91.
In the following, skew correction of the sheet of recording paper in image forming apparatus 100, that is, the process for deflecting the sheet of recording paper just in front of registration roller pair 13 will be described.
Referring to
Between registration roller pair 13 and pre-registration roller pair 12e, a first conveyor guide 150 and a second conveyor guide 152 are arranged. The first and second conveyor guides 150 and 152 are arranged spaced by a prescribed distance. The first conveyor guide 150 has a recessed portion, to increase the distance to the second conveyor guide 152. This prevents significant bending and buckling of the sheet of recording paper, and thus, the sheet of recording paper can be moderately deflected in one direction.
Near the pre-registration roller pair 12e (on the upstream side of paper feeding path S), a sensor 160 is arranged. Sensor 160 detects the leading edge of the sheet of recording paper fed along paper feeding path S. Any sensor 160 may be used, as long as it can detect the leading edge of conveyed sheet of recording paper. By way of example, sensor 160 may be a photo sensor including an actuator. It is also possible to place a light emitting device and a light receiving device on opposite sides of the paper feeding path S, to form sensor 160.
Referring to
Registration roller driving motor 212 and conveyor roller driving motor 214 are stepping motors. Rotation rate of a stepping motor is determined by the frequency of input pulses. The stepping motor receives pulse signals of a prescribed sequence from motor driver 210, and changes the state of driving (state of rotation) accordingly. To motor driver 210, a prescribed control signal (a signal indicating the timing of activating and suspending registration roller driving motor 212 and conveyor roller driving motor 214) is transmitted from CPU 200. In response, motor driver 210 reads pulse signals of a sequence corresponding to the control signal (instruction) from CPU 200 from ROM 202, and outputs the signals to registration roller driving motor 212 and conveyor roller driving motor 214. Motor driver 210 may be realized as a general purpose or dedicated electronic circuit and a program for operating the circuit. Alternatively, motor driver 210 may be implemented as a dedicated electronic circuit including a semiconductor device such as an ASIC.
Referring to
At step 300, CPU 200 determines whether or not sensor 160 has detected a sheet of recording paper. Specifically, CPU 200 determines whether or not the signal from sensor 160 is at a level that is output when a sheet of recording paper is detected. By way of example, the output signal from sensor 160 is at the low level when no sheet is detected, and it attains to the high level when a sheet of recoding paper is detected. If it is determined that a sheet of recording paper is detected, the control proceeds to step 302. Otherwise, step 300 is repeated.
At step 302, CPU 200 transmits a control signal for rotating the conveyor roller pair (pre-registration roller pair) 12e to motor driver 210. In response, motor driver 210 outputs the pulse signals of a prescribed sequence to conveyor roller driving motor 214, and conveyor roller driving motor 214 starts rotation. Further, CPU 200 acquires information representing the current time (hereinafter simply referred to as current time) from timer 208, and stores it as information representing the start time (hereinafter simply referred to as start time) in a prescribed area of RAM 204.
At step 304, CPU 200 determines whether or not a prescribed time period Ta has passed from the start of rotation of conveyor roller pair (pre-registration roller pair) 12e. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 302, and determines whether the resulting value is longer than the time period Ta. If it is determined that the time period Ta has passed, the control proceeds to step 306. Otherwise, step 304 is repeated.
This stage corresponds to time t1 to t3 of
At step 306, CPU 200 transmits a control signal for rotating registration roller pair 13 to motor driver 210. In response, motor driver 210 outputs pulse signals of a prescribed sequence to registration roller driving motor 212, and registration roller driving motor 212 starts rotation. Further, CPU 200 obtains the current time from timer 208, and temporarily stores it as the start time, in a prescribed area of RAM 204.
At step 308, CPU 200 determines whether or not a prescribed time period Tb has passed from the start of rotation of registration roller pair 13. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 306, and determines whether the resulting value is longer than the time period Tb. If it is determined that the time period Tb has passed, the control proceeds to step 310. Otherwise, step 308 is repeated. This stage corresponds to t3 to t4 of
At step 310, CPU 200 transmits a control signal for stopping conveyor roller pair (pre-registration roller pair) 12e to motor driver 210. In response, motor driver 210 outputs pulse signals of a prescribed sequence to conveyor roller driving motor 214, and the rotation of conveyor roller driving motor 214 is suspended. Further, CPU 200 obtains the current time from timer 208, and temporarily stores it as the start time, in a prescribed area of RAM 204.
At step 312, CPU 200 determines whether or not a prescribed time period Tc has passed from when rotation of conveyor roller pair (pre-registration roller pair) 12e is suspended. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 310, and determines whether the resulting value is longer than the time period Tc. If it is determined that the time period Tc has passed, the control proceeds to step 314. Otherwise, step 312 is repeated. In this stage (the time period from t4 to t5 of
At step 314, CPU 200 transmits a control signal for rotating conveyor roller pair (pre-registration roller pair) 12e to motor driver 210. In response, motor driver 210 outputs pulse signals of a prescribed sequence to conveyor roller driving motor 214, and conveyor roller driving motor 214 starts rotation.
At step 316, CPU 200 determines whether or not registration roller pair 13 has completed feeding of the sheet of recording paper. By way of example, if a sensor for detecting a trailing edge of the sheet of recording paper is arranged on the downstream side of registration roller pair 13, CPU 200 determines the signal level of the sensor. Alternatively, CPU 200 may determine whether or not a prescribed time period has passed from the start of rotation of conveyor roller pair (pre-registration roller pair) 12e at step 314. If it is determined that feeding of the sheet of recording paper is completed, the control proceeds to step 318. Otherwise, step 316 is repeated.
At step 318, CPU 200 transmits a control signal for stopping registration roller pair 13 and conveyor roller pair (pre-registration roller pair) 12e to motor driver 210. In response, motor driver 210 outputs pulse signals of a prescribed sequence to registration roller driving motor 212 and conveyor roller driving motor 214, and registration roller driving motor 212 and conveyor roller driving motor 214 are stopped.
At step 320, CPU 200 determines whether or not an end instruction has been received. The end instruction is, for example, turning OFF of the power of image forming apparatus 100. If it is determined that an end instruction is received, the present program ends. Otherwise, the control returns to step 300. Thus, when image forming apparatus 100 is operated by a user and printing of a prescribed number of copies is instructed, the above-described process is repeated until printing of the prescribed number of copies is completed.
As described above, in image forming apparatus 100, when a sheet of recording paper is fed to pre-registration roller pair 12e (time t1), rotation of pre-registration roller pair 12e is started to have the leading edge of the sheet of recording paper abut registration roller pair 13 that is stationary (time t2), and pre-registration roller pair 12e is continuously rotated thereafter. Thus, the sheet of recording paper is appropriately deflected between the first and second conveyor guides 150 and 152. In image forming apparatus 100, at a time point (time t3) when the sheet of recording paper is deflected appropriately, rotation of registration roller pair 13 is started, at a time point (time t4) when a prescribed time period (Tb) thereafter has passed, rotation of pre-registration roller pair 12e is suspended, and at a time point (time t5) when a prescribed time period (Tc) thereafter has passed, pre-registration roller pair 12e is again rotated. Thus, as shown in
The time periods Ta to Tc may be appropriately set in consideration of the specification of image forming apparatus (such as the number of sheets that can be handled per unit time), characteristics of stepping motors driving the registration roller pair and the conveyor roller pair, the amount of deflection of the sheet of recording paper and the like.
Though feeding of a sheet of recording paper has been described above, the application is not limited to the above. By way of example, the invention is also applicable to automatic document feeder 120 for feeding a document to a scanning position. This will be specifically described in the following.
Referring to
Image reading device 90 includes a platen glass 44, a first scanning unit 45, a second scanning unit 46, an image forming lens 47, and a CCD (Charge Coupled Device) 48. When a document placed on platen glass 44 is read, the first and second scanning units 45 and 46 are used.
The first scanning unit 45 includes an illumination device 51 and a first reflection mirror 52. Illumination device 51 includes an LED array 77 and a light guiding member 78. The first scanning unit 45 moves at a constant velocity V to a sub-scanning direction Y by a distance corresponding to the document size, while exposing the document on platen glass 44 using illumination device 51. The first scanning unit 45 reflects reflected light by the first reflection mirror 52 to the second scanning unit 46. In this manner, the first scanning unit 45 scans an image (including color or black-and-white characters, a figure, a photograph or the like) on the surface of the document in the sub-scanning direction Y. The second scanning unit 46 includes a second reflection mirror 53 and a third reflection mirror 54. The second scanning unit 46 moves at a velocity V/2 following the first scanning unit 45, and reflects the light reflected from the document by the second and third reflection mirrors 53 and 54 to image forming lens 47. Image forming lens 47 collects the light reflected from the document to CCD 48, and forms an image of the document surface on CCD 48. CCD 48 scans the document image repeatedly in the main scanning direction (the direction vertical to the surface of
Image reading device 90 can read not only the stationary document on platen glass 44 but also images on the surface of a document fed by automatic document feeder 120. In that case, the first scanning unit 45 is moved to a reading area below document reading glass 84 as shown in
In automatic document feeder 120, a pick-up roller 55 is rotated with the roller pressed on a document on document tray 56, to draw a sheet of document. Automatic document feeder 120 conveys the drawn document to have the leading edge of the document abut a registration roller pair 85, so as to align the leading edge of document, and then, passes the document through document reading glass 84 and a reading guide plate 86, and discharges the document through a discharge roller pair 58 to a discharge tray 49.
When the document is fed, illumination device 51 of the first scanning unit 45 illuminates the document surface through document reading glass 84. The light reflected from the document surface is guided by the reflection mirrors of the first and second scanning units 45 and 46 to image forming lens 47, collected by image forming lens 47 to CCD 48, and the image on the document surface is formed on CCD 48. In this manner, image reading device 90 reads the image on the document surface.
When the back side of the document is to be read, in automatic document feeder 120, an intermediate tray 67 is rotated about its shaft 69 as represented by a chain-dotted line, and while the document is discharged from discharge roller pair 58 to discharge tray 49, discharge roller pair 58 is stopped, and the document is received by intermediate tray 67. In this state, in automatic document feeder 120, discharge roller pair 58 is rotated in reverse direction, so that the document is guided through a reverse feeding path 68 to registration roller pair 85, and the document is turned over. In the similar manner as reading the image on the front side, image reading device 90 reads the image on the back side of the document. Thereafter, automatic document feeder 120 returns the intermediate tray 67 to the original position represented by the solid line, and discharges the document through discharge roller pair 58 to discharge tray 49.
If the document fed by registration roller pair 85 passes askew through document reading glass 84 and reading guide plate 86, the document will be scanned askew, and desired image data cannot be obtained. Therefore, as in image forming, skew correction here is also desirable.
When the front surface of a document is to be read, a process similar to the process of steps 300 to 318 may be executed, in which registration roller pair 85 serves as registration roller pair 13 for feeding the sheet of recording paper and pick-up roller 55 serves as pre-registration roller pair 12e. When the back surface of the document is to be read, the process similar to the process of steps 300 to 318 may be executed, in which registration roller pair 85 serves as registration roller pair 13 for feeding the sheet of recording paper and discharge roller pair 58 for reverse rotation serves as pre-registration roller pair 12e. By such an approach, no matter whether the front surface or back surface of the document is to be read, the document can be passed between document reading glass 84 and reading guide plate 86 with the skew corrected.
In place of using pick-up roller 55 as pre-registration roller pair 12e, a new conveyor roller pair may be provided along the document feeding path between pick-up roller 55 and registration roller pair 85 (for example, at a position closer to registration roller pair 85 than pick-up roller 55), and the process similar to the process of steps 300 to 318 may be executed using the new conveyor roller pair as pre-registration roller pair 12e. In that case, also when the back surface of the document is read, similar to the process of steps 300 to 318 may be executed, using the new conveyor roller pair as pre-registration roller pair 12e.
In the foregoing, an example in which the amount of deflection of the sheet of recording paper is adjusted by CPU 200 in accordance with the elapsed time has been described. The example above, however, is not limiting. By way of example, CPU 200 may adjust the amount of deflection of the sheet of recording paper by determining whether or not a prescribed number of pulses have been transmitted to registration roller driving motor 212 or to conveyor roller driving motor 214. CPU 200 may obtain the number of pulses transmitted to registration roller driving motor 212 and to conveyor roller driving motor 214 from, for example, motor driver 210.
Further, though an example in which the conveyor roller pair is fully stopped after the time period Tb from the start of rotation of registration roller pair 13 has been described, the example is not limiting. By way of example, as shown in
Further, as shown in
If CPU 200 controls motor driver 210 by determining the elapsed time or the number of pulses transmitted to the motor, what can be controlled by CPU 200 is the timing of transmitting the control signals. Therefore, the velocity waveforms of the roller are determined at time points t1, t4 and t5 (see
Since the timing at which feeding of the sheet of recording paper is completed is substantially constant, pulse sequences including the timing of stopping registration roller pair 13 and pre-registration roller pair 12e can also be determined. If such pulse sequences are used, provision of a sensor for detecting the trailing edge of the sheet of recording paper on the downstream side of registration roller pair 13 becomes unnecessary.
In the foregoing, an example in which motors for driving registration roller pair 13 and pre-registration roller pair 12e are provided respectively has been described. This example, however, is not limiting. By way of example, using electromagnetic clutches, registration roller pair 13 and pre-registration roller pair 12e may be driven by one motor. Specifically, a first electromagnetic clutch for transmitting motor rotation to registration roller pair 13 and a second electromagnetic clutch for transmitting motor rotation to pre-registration roller pair 12e may be provided, and control signals are supplied from the CPU to the first and second electromagnetic clutches, to connect or open the first and second electromagnetic clutches. By such an approach, rotations of registration roller pair 13 and pre-registration roller pair 12e can be controlled as shown in
In the foregoing, an example of step 300 has been described in which rotation of pre-registration roller pair 12e is started when a sheet of recording paper is detected by sensor 160 and even when the leading edge of the sheet reaches near registration roller pair 13, rotation of pre-registration roller pair 12e is not suspended so that the leading edge of the sheet of recording paper abuts the registration roller pair. This example, however, is not limiting. As in the conventional art, when the leading edge of the sheet of recording paper reaches near registration roller pair 13, pre-registration roller pair 12e may be temporarily stopped. In that case, from this suspended state of pre-registration roller pair 12e, step 302 may be executed at time t1. Here, the time period between t1 and t2 is short, and since the leading edge of the sheet of recording paper abuts registration roller pair 13 at a low velocity, hitting sound (collision noise) can be reduced.
An image forming apparatus in accordance with a second embodiment of the present invention has the same configuration as the image forming apparatus in accordance with the first embodiment described with reference to
Referring to
At step 600, CPU 200 determines whether or not sensor 160 has detected a sheet of recording paper. Specifically, CPU 200 determines whether or not the signal from sensor 160 is at a level that is output when a sheet of recording paper is detected. By way of example, the output signal from sensor 160 is at the low level when no sheet is detected, and it attains to the high level when a sheet of recoding paper is detected. If it is determined that a sheet of recording paper is detected, the control proceeds to step 602. Otherwise, step 600 is repeated.
At step 602, CPU 200 transmits a control signal for rotating the pre-registration roller pair (conveyor roller pair) 12e to motor driver 210. Receiving the control signal, motor driver 210 outputs the pulse signals of prescribed sequence to conveyor roller driving motor 214 as described above. Receiving the pulse signals, conveyor roller driving motor 214 starts rotation, and thus, pre-registration roller pair 12e rotates. Further, CPU 200 obtains the current time from timer 208, and stores it as the start time in a prescribed area of RAM 204.
At step 604, CPU 200 determines whether or not a prescribed time period Ta has passed from the start of rotation of pre-registration roller pair 12e. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 602, and determines whether the resulting value is longer than the time period Ta. If it is determined that the time period Ta has passed, the control proceeds to step 606. Otherwise, step 604 is repeated.
At step 606, CPU 200 transmits a control signal for stopping pre-registration roller pair 12e to motor driver 210. Receiving the control signal, motor driver 210 stops output of the pulse signals to conveyor roller driving motor 214. Consequently, conveyor roller driving motor 214 stops, and rotation of pre-registration roller pair 12e is suspended. Here, if the rotation is to be suspended with the number of rotations controlled, for example, the number of pulses per unit time is reduced linearly to zero. Further, CPU 200 obtains the current time from timer 208, and temporarily stores it as the start time in a prescribed area of RAM 204.
Steps 600 to 606 are executed in a time period up to time t0 of
At step 608, CPU 200 determines whether or not a prescribed time period Tb has passed after pre-registration roller pair 12e was stopped at time t0. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 606, and determines whether the resulting value is longer than the time period Tb. If it is determined that the time period Tb has passed, the control proceeds to step 610. Otherwise, step 608 is repeated.
At step 610, CPU 200 transmits a control signal for rotating pre-registration roller pair 12e to motor driver 210. Receiving the control signal, motor driver 210 outputs pulse signals of a prescribed sequence (for example, a sequence in which number of pulses per unit time increases linearly) to conveyor roller driving motor 214. Receiving the pulse signals, conveyor roller driving motor 214 starts rotation. Consequently, pre-registration roller pair 12e starts rotation, and the velocity of rotation is increased at a constant rate of acceleration. Further, CPU 200 obtains the current time from timer 208, and stores it as the start time in a prescribed area of RAM 204. Step 610 is executed at time t1 of
At step 612, CPU 200 determines whether or not a prescribed time period Tc has passed from the start of rotation of pre-registration roller pair 12e at time t1. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 610, and determines whether the resulting value is longer than the time period Tc. If it is determined that the time period Tc has passed, the control proceeds to step 614. Otherwise, step 612 is repeated.
The time period in which steps 610 to 612 are executed is the period from t1 to t2 of
At step 614, CPU 200 transmits a control signal to have pre-registration roller pair 12e, which is rotating with acceleration, rotate at a constant velocity (control signal to stop acceleration) to motor driver 210. Receiving the control signal, motor driver 210 outputs pulse signals of a prescribed sequence (for example, pulse signals of equal interval) to conveyor roller driving motor 214. Receiving the control signal, conveyor roller driving motor 214 stops acceleration, and rotates at a constant velocity. Thus, pre-registration roller pair 12e comes to rotate at a constant velocity V1. Further, CPU 200 obtains the current time from timer 208, and stores it as the start time in a prescribed area of RAM 204. Step 614 is executed at time t2 of
At step 616, CPU 200 determines whether a prescribed time period Td has passed from when rotation of pre-registration roller pair 12e at constant velocity V1 started at time t2. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 614, and determines whether the resulting value is longer than the time period Td. If it is determined that the time period Td has passed, the control proceeds to step 618. Otherwise, step 616 is repeated.
At step 618, CPU 200 transmits a control signal for rotating registration roller pair 13 to motor driver 210. Receiving the control signal, motor driver 210 outputs pulse signals of a prescribed sequence (for example, a sequence in which number of pulses per unit time increases linearly) to registration roller driving motor 212. Receiving the pulse signals, registration roller driving motor 212 starts rotation. Accordingly, registration roller pair 13 starts rotation, and the rotation accelerates at the same constant rate of acceleration as that of pre-registration roller pair 12e at step 610. Further, CPU 200 obtains the current time from timer 208, and stores it as the start time in a prescribed area of RAM 204. Step 618 is executed at time t4 of
At step 620, CPU 200 determines whether or not a prescribed time period Te has passed from the start of rotation of registration roller pair 13 at time t4. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 618, and determines whether the resulting value is longer than the time period Te. If it is determined that the time period Te has passed, the control proceeds to step 622. Otherwise, step 620 is repeated.
At step 622, CPU 200 transmits a control signal for accelerating the rotation of pre-registration roller pair 12e to motor driver 210. Receiving the control signal, motor driver 210 outputs pulse signals of a prescribed sequence (for example, a sequence in which number of pulses per unit time increases linearly) to conveyor roller driving motor 214. Receiving the pulse signals, rotation of conveyor roller driving motor 214 accelerates. Thus, rotation of pre-registration roller pair 12e accelerates at the same constant rate of acceleration as in the time period between t1 and t2. Further, CPU 200 obtains the current time from timer 208, and stores it as the start time in a prescribed area of RAM 204. Step 622 is executed at time t5 of
After the start of rotation of registration roller pair 13 at step 618 until immediately before the start of acceleration of pre-registration roller pair 12e at step 622, pre-registration roller pair 12e is rotating at the constant velocity V1, while the velocity of registration roller pair 13 is not yet as high as V1. Therefore, the velocity at which the sheet of recording paper is introduced into the space between the first and second conveyor guides 150 and 152 by pre-registration roller pair 12e is faster than the velocity at which the sheet of recording paper is fed out from registration roller pair 13. Thus, the sheet of recording paper further deflects. This state is shown in (D) of
At step 624, CPU 200 determines whether or not a prescribed time period Tf has passed from when acceleration of the rotation of pre-registration roller pair 12e was started at time t5. Specifically, CPU 200 obtains the current time from timer 208, calculates the elapsed time from the start time stored in RAM 204 at step 622, and determines whether the resulting value is longer than the time period Tf. If it is determined that the time period Tf has passed, the control proceeds to step 626. Otherwise, step 624 is repeated.
At step 626, CPU 200 transmits a control signal for rotating registration roller pair 13 and pre-registration roller pair 12e at a constant velocity (a control signal for stopping acceleration) to motor driver 210. Receiving the control signal, motor driver 210 outputs pulse signals of a prescribed sequence (for example pulse signals of equal interval) to registration roller driving motor 212 and conveyor roller driving motor 214. Receiving the pulse signals, registration roller driving motor 212 and conveyor roller driving motor 214 rotate at a constant process velocity (the velocity of feeding the recording paper at the time of image formation) Vc. Step 626 is executed at time t6 of
After the start of acceleration of pre-registration roller pair 12e at time t5, registration roller pair 13 and pre-registration roller pair 12e are rotating at the same velocity. Therefore, the velocity at which the sheet of recording paper is fed out from registration roller pair 13 is the same as the velocity at which pre-registration roller pair 12e feeds the sheet of recording paper into the space between the first and second conveyor guides 150 and 152. Thus, the amount of deflection of the sheet of recording paper is kept constant. This state is shown in (E) of
At step 628, CPU 200 determines whether or not registration roller pair 13 has completed feeding of the sheet of recording paper. By way of example, if a sensor for detecting a trailing edge of the sheet of recording paper is arranged on the downstream side of registration roller pair 13, CPU 200 determines the signal level of the sensor. Alternatively, CPU 200 may determine whether or not a prescribed time period has passed from the start of rotation of pre-registration roller pair 12e at step 614. If it is determined that feeding of the recording paper has completed, the control proceeds to step 630. Otherwise, step 628 is repeated.
At step 630, CPU 200 transmits a control signal for stopping registration roller pair 13 and pre-registration roller pair 12e to motor driver 210. Receiving the control signal, motor driver 210 stops output of pulse signals to registration roller driving motor 212 and conveyor roller driving motor 214. Thus, rotations of registration roller driving motor 212 and conveyor roller driving motor 214 are stopped. Here, if the rotation is to be stopped with the number of rotations controlled, for example, the number of pulses per unit time is reduced linearly to zero.
At step 632, CPU 200 determines whether or not an end instruction has been received. The end instruction is, for example, turning OFF of the power of image forming apparatus 100. If it is determined that an end instruction is received, the present program ends. Otherwise, the control returns to step 600. Thus, when image forming apparatus 100 is operated by a user and printing of a prescribed number of copies is instructed, the above-described process is repeated until printing of the prescribed number of copies is completed.
As described above, in image forming apparatus 100, when a sheet of recording paper is fed to pre-registration roller pair 12e, rotation of pre-registration roller pair 12e is started to have the leading edge of the sheet of recording paper fed to immediately in front of registration roller pair 13 that is stationary, and then, rotation of pre-registration roller pair 12e is temporarily suspended (time t0). Thereafter, image forming apparatus 100 starts rotation of pre-registration roller pair 12e (time t1) to have the leading edge of the sheet of recording paper abut registration roller pair 13, and continuously rotates pre-registration roller pair 12e thereafter. Thus, the sheet of recording paper is appropriately deflected between the first and second conveyor guides 150 and 152 (time t4). In image forming apparatus 100, at a time point (time t4) when the sheet of recording paper is deflected appropriately, rotation of registration roller pair 13 is started, and at a time point (time t5) when a prescribed time period (Te) thereafter has passed, rotation of pre-registration roller pair 12e is again accelerated. Then, registration roller pair 13 and pre-registration roller pair 12e rotate at the same velocity and, hence, the sheet of recording paper is fed by registration roller pair 13 and pre-registration roller pair 12e with appropriate deflection of the sheet maintained, as shown in (D) of
After a prescribed time period (Tf) from the start of re-acceleration of pre-registration roller pair 12e (time t6), image forming apparatus 100 has registration roller pair 13 and pre-registration roller pair 12e rotate at the constant velocity Vc. Thus, the sheet of recording paper with the skew corrected is fed to transfer roller 10. When the sheet of recording paper leaves and is away from pre-registration roller pair 12e, deflection of the sheet is not maintained, while skew-correction of the sheet of recording paper is maintained by registration roller pair 13.
The time periods Ta to Tf may be appropriately set in consideration of the specification required of image forming apparatus (such as the number of sheets that can be handled per unit time), characteristics of stepping motors driving the registration roller pair 13 and the conveyor roller pair 12e, the amount of deflection of the sheet of recording paper and the like.
The constant velocity V1 at which pre-registration roller pair 12e is rotated in the time period of t2 to t5 can also be set appropriately. If the velocity V1 is low, the time period Tc+Td (time t1-t4) from the start of rotation of pre-registration roller pair 12e until an appropriate deflection is formed becomes longer, while the amount of excessive deflection becomes smaller than in the conventional example. On the other hand, if the velocity V1 is high, the time period Tc+Td between time t1 and t4 becomes shorter, while the amount of excessive deflection becomes larger. This will be described with reference to
As can be seen from
As described above, it is preferred that the rate of acceleration of pre-registration roller pair 12e is the same as that of registration roller pair 13, and that the timing (t5) of re-accelerating pre-registration roller pair 12e from the constant velocity V1 is when the velocity of registration roller pair 13 becomes equal to the constant velocity V1 of the pre-registration roller pair. The time t5, however, may be slightly before or after when the velocity of registration roller pair 13 becomes equal to the constant velocity V1 of the pre-registration roller pair, provided that successful skew correction is possible without causing buckling.
In the foregoing, an example has been described in which the rate of acceleration of registration roller pair 13 is constant and the same as that of pre-registration roller pair 12e. The example, however, is not limiting. Further, though an example in which the rate of acceleration of pre-registration roller pair 12e is equal between t1 and t2 and between t5 and t6 has been described, it is not limiting. Even if there is some difference in the rate of acceleration, it is possible to appropriately execute skew correction of recording paper and to prevent buckling, by adjusting time t4, t5 or t6.
Though an example of feeding a sheet of recording paper has been described above, it is not limiting. Similar to the first embodiment, the second embodiment is also applicable to automatic document feeder 120 for feeding a document to a scanning position. This will be specifically described in the following. Automatic document feeder 120 and image reading device 90 are the same as those described above with reference to
When the front surface of a document is to be read, a process similar to the process of steps 600 to 632 may be executed, in which registration roller pair 85 serves as registration roller pair 13 for feeding the sheet of recording paper and pick-up roller 55 serves as pre-registration roller pair 12e. When the back surface of the document is to be read, the process similar to the process of steps 600 to 632 may be executed, in which registration roller pair 85 serves as registration roller pair 13 for feeding the sheet of recording paper and discharge roller pair 58 for reverse rotation serves as pre-registration roller pair 12e. By such an approach, no matter whether the front surface or back surface of the document is to be read, the document can be passed between document reading glass 84 and reading guide plate 86 with the skew corrected. Here, the constant velocity of the pre-registration roller pair (pick-up roller 55 or reverse-rotated paper discharge roller pair 58) should be close to the process velocity of document scanning or a velocity not very much lower than the process velocity.
In place of using pick-up roller 55 as pre-registration roller pair 12e, a new conveyor roller pair may be provided along the document feeding path between pick-up roller 55 and registration roller pair 85 (for example, at a position closer to registration roller pair 85 than pick-up roller 55), and the process similar to the process of steps 600 to 632 may be executed using the new conveyor roller pair as pre-registration roller pair 12e. In that case, also when the back surface of the document is read, similar to the process of steps 600 to 632 may be executed, using the new conveyor roller pair as pre-registration roller pair 12e.
In the foregoing, an example in which the amount of deflection of the sheet of recording paper is adjusted by CPU 200 in accordance with the elapsed time has been described. The example above, however, is not limiting. By way of example, CPU 200 may adjust the amount of deflection of the sheet of recording paper by determining whether or not a prescribed number of pulses has been transmitted to registration roller driving motor 212 or to conveyor roller driving motor 214. CPU 200 may obtain the number of pulses transmitted to registration roller driving motor 212 and to conveyor roller driving motor 214 from, for example, motor driver 210.
Further, as shown in
If CPU 200 controls motor driver 210 by determining the elapsed time or the number of pulses transmitted to the motor, what can be controlled by CPU 200 is the timing of transmitting the control signals. Therefore, the velocity waveforms of the roller are determined at time points t1, t3, t4, t5 and t6 (see
Since the timing at which feeding of the sheet of recording paper is completed is substantially constant, pulse sequences including the timing of stopping registration roller pair 13 and pre-registration roller pair 12e can also be determined. If such pulse sequences are used, provision of a sensor for detecting the trailing edge of the sheet of recording paper on the downstream side of registration roller pair 13 becomes unnecessary.
In the foregoing, an example in which motors for driving registration roller pair 13 and pre-registration roller pair 12e are provided respectively has been described. This example, however, is not limiting. By way of example, using electromagnetic clutches, registration roller pair 13 and pre-registration roller pair 12e may be driven by one motor. Specifically, a first electromagnetic clutch for transmitting motor rotation to registration roller pair 13 and a second electromagnetic clutch for transmitting motor rotation to pre-registration roller pair 12e may be provided, and control signals are supplied from the CPU 200 to the first and second electromagnetic clutches, to connect or open the first and second electromagnetic clutches. By such an approach, rotations of registration roller pair 13 and pre-registration roller pair 12e can be controlled as shown in
In the foregoing, an example of step 600 has been described in which rotation of pre-registration roller pair 12e is started when a sheet of recording paper is detected by sensor 160 and when the leading edge of the sheet reaches near registration roller pair 13, rotation of pre-registration roller pair 12e is temporarily suspended. The example, however, is not limiting. Even when the leading edge of the sheet reaches near registration roller pair 13, rotation of pre-registration roller pair 12e may not be suspended, and the leading edge of the sheet of recording paper may abut registration roller pair 13. In that case, hitting sound (collision noise) generates when the leading edge of the sheet abuts registration roller pair 13. However, it is possible to feed the sheets of recording paper faster and, hence, continuous image formation can be done at high speed.
The embodiments as have been described here are mere examples and should not be interpreted as restrictive. The scope of the present invention is determined by each of the claims with appropriate consideration of the written description of the embodiments and embraces modifications within the meaning of, and equivalent to, the languages in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-233013 | Oct 2011 | JP | national |
| 2011-275806 | Dec 2011 | JP | national |
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| 5967506 | Miki et al. | Oct 1999 | A |
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| 7328898 | Yasui | Feb 2008 | B2 |
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| 20120153566 | Ito et al. | Jun 2012 | A1 |
| Number | Date | Country |
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| 05-270693 | Oct 1993 | JP |
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| Entry |
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| Machine translation of Detailed Description section of JP 11-255380. |
| Number | Date | Country | |
|---|---|---|---|
| 20130099441 A1 | Apr 2013 | US |
