Patent Application
20240294347
This disclosure relates to a sheet feeding apparatus including a separation unit that separates a sheet by blowing air onto a plurality of sheets manually fed to be supported on a supporting portion, and an image forming apparatus including this sheet feeding apparatus.
In image forming apparatuses such as, for example, copy machines, facsimiles, and printers, as sheet feeding apparatuses feeding a sheet to an image forming unit that forms an image on a sheet, manual sheet feed trays and sheet feed cassettes are included, or sheet feed decks are externally attached. Further, in recent years, there is an increasing demand to form the image on various types of the sheets, and, sometimes, sheets with a smooth surface, such as coated paper, are used. When a sheet bundle composed of the sheets with the smooth surface as described above is set to the sheet feeding apparatus as described above, since an adhesion force between the sheets is high, there is a risk of defective feeding resulting from a difficulty in separating the sheets. Therefore, a technique that is known as an air separation in which air blows to a set sheet bundle so as to levitate and thus separate the sheet is suggested (refer to Japanese Patent Laid-Open No. H04-23747).
Incidentally, in the image forming apparatuses, a pair of side edge regulation plates that regulate the sheet from both sides in a width direction are disposed in the manual sheet feed tray onto which a user sets the sheet by manual feeding, and a position of the sheet in the width direction is regulated. In a case where positions of the side edge regulation plates are aligned with the size of a set sheet in the width direction, even in a case where the air separation is performed to levitate the sheet as described in Japanese patent Laid-Open No. H04-23747, the position of the sheet in the width direction is regulated. However, for example, in a case where the user moves the side edge regulation plates subsequent to setting the sheet, or in a case where the user fails to properly regulate the position of the sheet in the width direction by the side edge regulation plates when setting the sheet, there is a risk of the disruption of the posture of the sheet that has been levitated by the air separation. When the sheet with such a disrupted posture is fed, it causes a problem of creating the skew of the sheet, which can lead to a sheet jam.
According to a first aspect of the present invention, a sheet feeding apparatus includes a supporting portion configured to support a plurality of sheets that have been manually set, a sheet feeding unit configured to feed the sheets supported by the supporting portion, a side edge regulation plate configured to move in a width direction perpendicular to a feed direction, the side edge regulation plate being configured to regulate a position of the sheets supported by the supporting portion in the width direction, a separation unit configured to separate the sheets by blowing air onto the plurality of sheets supported by the supporting portion, a regulation plate position detection unit configured to detect a position of the side edge regulation plates in the width direction, and a control unit configured to execute a separation mode so as to perform an air-blow operation by the separation unit in feeding the sheets by the sheet feeding unit. In the separation mode, in a case where the position of the side edge regulation plate detected by the regulation plate position detection unit does not correspond to size of the sheets supported by the supporting portion in the width direction, the control unit is configured to stop the air-blow operation.
According to a second aspect of the present invention, a sheet feeding apparatus includes a supporting portion configured to support a plurality of sheets that have been manually set, a sheet feeding unit configured to feed the sheets supported by the supporting portion, a side edge regulation plate configured to move in a width direction perpendicular to a feed direction, the side edge regulation plate being configured to regulate a position of the sheets supported by the supporting portion in the width direction, a separation unit configured to separate the sheets by blowing air onto the plurality of sheets that are supported by the supporting portion, a regulation plate position detection unit configured to detect a position of the side edge regulation plate in the width direction, and a control unit configured to execute a separation mode so as to perform an air-blow operation by the separation unit in feeding the sheets by the sheet feeding unit. In the separation mode, in a case where a position of the side edge regulation plate, detected by the regulation plate position detection unit, subsequent to starting the air-blow operation differs from a position of the side edge regulation plate, detected by the regulation plate position detection unit, prior to starting the air-blow operation, the control unit is configured to stop the air-blow operation.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, with reference to drawings, an embodiment of this disclosure will be described in detail. First, using
As illustrated in
As illustrated in
The image forming unit 201B utilizes a four-drum full-color system. The image forming unit 201B includes a laser scanner 210 and four process cartridges 211Y, 211M, 211C, and 211K, forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). Each of the process cartridges 211 includes a photosensitive drum 212, a charge roller 213, serving as a charge unit, and a developing unit 214, serving as a developing unit. Further, the image forming unit 201B includes an intermediate transfer unit 201C arranged on the top of the process cartridges 211, and a fixing unit 201E. To be noted, toner cartridges 215 for supplying toner to the developing units 214 are disposed above the intermediate transfer unit 201C.
The intermediate transfer unit 201C includes an intermediate transfer belt 216 wound around a drive roller 216a and a tension roller 216b. To be noted, primary transfer rollers 219 that come into contact the intermediate transfer belt 216 at positions facing the photosensitive drums 212 are disposed inside of the intermediate transfer belt 216. Here, the intermediate transfer belt 216 is rotated in an arrow direction in
Then, a negatively charged toner images of each color on the photosensitive drums are sequentially transferred in multiple layers onto the intermediate transfer belt 216 by the primary transfer rollers 219. At a position facing the drive roller 216a of the intermediate transfer unit 201C, a secondary transfer roller 217 for transferring a color image formed on the intermediate transfer belt 216 onto the sheet S is disposed. A secondary transfer portion 201D is formed between these intermediate transfer belt 216 and secondary transfer roller 217. Further, above this secondary transfer roller 217, the fixing unit 201E including a pressing roller 220a and a heating roller 220b is arranged. Further, above this fixing unit 201E, a first sheet discharge roller pair 225a, a second sheet discharge roller pair 225b, and a duplex reverse portion 201F are arranged. In this duplex reverse portion 201F, a reverse roller pair 222 that can rotate in both directions, a re-conveyance path R for conveying the sheet, on whose one surface the image has been formed, again to the image forming unit 201B, and the like are disposed.
In a lower part of the apparatus body 210A, a plurality of sheet feed units 230 feeding the placed sheet S to the image forming unit 201B are disposed. Each of the plurality of sheet feed units 230 includes a sheet feed cassette 1, storing a plurality of sheets (sheet bundle), and a sheet feeding unit 6, serving as a sheet feeding unit feeding the sheet S stored in the sheet feed cassette 1. The sheet feeding unit 6 includes a pickup roller 2, a feed roller 3, and a retard roller 4. The feed roller 3 and the retard roller 4 serve as a separation unit separating the sheet S sent in multiples from the pickup roller 2.
Further, the sheet feed deck 800 sending the placed sheet S to the image forming unit 201B is disposed on the right side of the apparatus body 201A in
Further, the manual sheet feed portion 235 feeding the sheet S from a plurality of manually fed sheets S (sheet bundle) to the image forming unit 201B is disposed on the right side surface of the apparatus body 201A in
To be noted, a media detection sensor 280, serving as a sheet type detection unit, is arranged in a conveyance path of the apparatus body 201A, and detects a grammage and surface properties of the sheet S by reading the sheet S that has been conveyed.
Next, an image forming operation of the image forming apparatus 201 will be described. First, for example, when the image information of a document has been read by the image reading apparatus 202, after image processing, this image information is converted into an electrical signal, and is transmitted to the laser scanner 210 of the image forming unit 201B. To be noted, this image information can be transmitted from, for example, a host apparatus 1500 (refer to
In the image forming unit 201B, surfaces of the photosensitive drums 212 have been charged to a predetermined polarity and potential by the charge units 213, and the surfaces of the photosensitive drums 212 are sequentially exposed by a laser light. Thereby, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on each of the photosensitive drums 212 of the respective process cartridges 211.
Thereafter, these electrostatic latent images are visualized by being developed with toners of each color, and, by applying a primary transfer bias to the primary transfer rollers 219, toner images of each color on the respective photosensitive drums are sequentially superimposed and transferred onto the intermediate transfer belt 216. Thereby, the toner image is formed on the intermediate transfer belt 216.
On the other hand, the sheet S fed from the sheet feed unit 230 (or the manual sheet feed portion 235, or the sheet feed deck 800) is conveyed to a registration roller pair (hereinafter, referred to as a registration roller pair) 240 constituted from a drive roller and driven roller. At this time, the drive of the registration roller pair 240 is being stopped, and a leading edge of the sheet S is abutted against the registration roller pair 240. Thereby, the leading edge of the sheet S follows the registration roller pair 240.
Thereafter, since the sheet S is continuously conveyed from such as the feed roller 3 (or the feed roller 502, or the feed roller 802), bending (loop) is formed in the sheet S. Thereafter, the registration roller pair 240 is driven in synchronization with a timing of the toner image on the intermediate transfer belt 216. Thereby, the skew of the sheet S is corrected by the registration roller pair 240, and the sheet S with the skew corrected is conveyed to the secondary transfer portion 201D by the registration roller pair 240.
Subsequently, in the secondary transfer portion 201D, the toner image is collectively transferred onto the sheet S by a secondary transfer bias applied to the secondary transfer roller 217. Then, the sheet S onto which the toner image has been transferred is conveyed to the fixing unit 201E, and, by being applied with heat and pressure in the fixing unit 201E, the toners of each color are melted and blended, so that the image is fixed on the sheet S as a color image.
Thereafter, the sheet S on which the image has been fixed is discharged to the sheet discharge space V by the first sheet discharge roller pair 225a or the second sheet discharge roller pair 225b disposed downstream of the fixing unit 200E in the sheet conveyance direction, and is loaded on a supporting portion 223 formed on a bottom surface of the sheet discharge space V. To be noted, when forming the image on both surfaces of the sheet S, after the image has been fixed, the sheet S is conveyed to the re-conveyance path R by the reverse roller pair 222, and is again conveyed to the secondary transfer portion 201D.
Next, using
As illustrated in
Further, in the manual sheet feed portion 235, the drawing roller pair 504 that feeds the sheet S to the image forming apparatus 201 by drawing the sheet S from the feed roller 502 is arranged downstream of this feed roller 502 in a sheet feed direction. Further, a feed sensor 505, serving as a sheet detection unit, is arranged between the feed roller 502 and the drawing roller pair 504. That is, the feed sensor 505 is arranged further downstream than the sheet feeding unit 506 in the sheet feed direction. This feed sensor 505 detects a passage of the sheet S by outputting a signal based on the presence or absence of the sheet S.
Further, as illustrated in
Further, as illustrated in
Next, using
When the plurality of sheets (sheet bundle) are placed on the manual sheet feed tray 236, the sheet presence detection sensor 401 described above detects the presence of the sheet. Further, in the width direction perpendicular to the sheet feed direction, the placed sheet is sandwiched by the side edge regulation plates 511 and 512 that are located on both side across the sheet, and is regulated in a correct posture along the sheet feed direction while being positioned in the width direction. Thereby, the skew of the sheet is prevented during feeding the sheet. These side edge regulation plates 511 and 512 are movable by sliding in arrow X1 and X2 directions that are the width direction, and can accommodate the sheets that vary in width sizes. Then, via a link, not shown, the side edge regulation plates 511 and 512 are connected to a sheet width volume sensor 405, serving as a regulation plate position detection unit detecting positions of these side edge regulation plates 511 and 512 in the width direction. In particular, with respect to a central processing unit (CPU) 101, the sheet width volume sensor 405 outputs an analog to digital (AD) value corresponding to the position of the side edge regulation plate 512, and the CPU 101 detects the sheet width in a main scanning direction based on the input AD value.
On the other hand, in the manual sheet feed tray 236, for example, near a central area in the width direction, on a straight line which serves as a center for feeding the sheet, a first sheet length sensor 403 and a second sheet length sensor 404 are located at different positions in the sheet feed direction. The first and second sheet length sensors 403 and 404 are configured as a flag-type sensor. The first and second sheet length sensors 403 and 404 are capable of detecting the length of the sheet in the sheet feed direction (hereinafter, referred to as a sheet length) in three stages based on ON/OFF statuses of each of the first and second sheet length sensors 403 and 404 activated in response to the length of the sheet placed on the manual sheet feed tray 236.
In particular, the sheet width volume sensor 405 is a sensor that outputs a 10 bit AD value, and provides an output that is substantially linear for AD values ranging from 0 to 0x400. As illustrated in
As illustrated in
Next, using
A control unit 100 of the present embodiment is included, for example, in the image forming apparatus 201, and is configured by including the CPU 101, a read only memory (ROM) 102, and a random access memory (RAM) 103. The control unit 100 is a control unit that performs control by coordinating the image forming apparatus 201, the sheet feed deck 800, and the manual sheet feed portion 235. The control unit 100 is connected to the host apparatus 1500 and the operation unit 730, and, while exchanging information with these connected apparatus and unit, performs such as signal processing and sequence control operations for various process equipment. To be noted, the host apparatus 1500 refers to external equipment such as a personal computer, an image scanner, and a facsimile. Further, the control unit 100 is connected to such as a fan control unit 402, a feed motor 520, serving as a motor that drives the pickup roller 501, and the sheet feed sensor 505 described above. Further, the control unit 100 is also connected to such as the sheet presence sensor 401, the first and second sheet length sensor 403 and 404, and the sheet width volume sensor 405, described above.
Next, using
As illustrated in
Problem in a Case where Sheet Width Size and Side Edge Regulation Plates are not Aligned
Here, using
For example, when a user places the sheet S on the manual sheet feed tray 236, sometimes, the user starts feeding the sheet (starts the job) without moving the side edge regulation plates 511 and 512 to align with the side edges of the sheet S, and thereby starts feeding the sheet with a gap D existing between the sheet S and the side edge regulation plates 511 and 512. Alternatively, for example, assume that, when the user placed the sheet S on the manual sheet feed tray 236, the side edge regulation plates 511 and 512 were moved to come into contact with the side edges of the sheet S. However, sometimes, the side edge regulation plates 511 and 512 are moved by such as being touched by the user after having started feeding the sheet, and the gap D is created between the sheet S and the side edge regulation plates 511 and 512. When the air blows from the sides of the sheet bundle by the air-blow portions 511A and 512A as described above with the gap D existing as described above, the levitated sheet S1 moves a distance corresponding to the gap D, and the posture of the sheet S1 is disrupted. That is, with respect to the sheet feed direction Y, positions of the leading edge and a trailing edge of the sheet S1 in the width direction X deviate, and the sheet S1 is inclined at an angle θ with respect to the sheet feed direction Y. When starting feeding the sheet S1 that is inclined as described above, the sheet S1 becomes skewed without undergoing correction, which leads to a problem that can cause a sheet jam. Therefore, in the present embodiment, as described below, an air-blow stop determination process is performed in sheet feed control.
Next, using
To be noted, the sheet feed control illustrated in
Upon receiving a start command for a job, for example, the printing of a predetermined number (for example, 15 sheets) of sheets of the coated paper from either the operation unit 730 or the external computer, not shown, the control unit 100 starts the sheet feed control that is executed as the separation mode illustrated in
Next, the control unit 100 drives the fan motors 511M and 512M (refer to
Next, the control unit 100 performs the air-blow stop determination process, that is, the control unit 100 determines whether or not to stop the air-blow operation (STEP S4). That is, as described in detail below, the control unit 100 determines whether or not there is a possibility that the sheet S is inclined due to the creation of the gap D (refer to
When proceeding to STEP S5, the control unit 100 waits until a predetermined time, for example, approximately 10 seconds has passed (STEP S5: No). That is, the predetermined time is set based on the duration of the time required for the fan motors 511M and 512M to start rotation from a standstill and attain a desired number of rotation (rotational speed), and a time required for stabilizing the levitation of the sheet S is included in the predetermined time. Then, when the predetermined time has passed (STEP S5: Yes), a feeding operation of the sheet S is started (STEP S6). To be noted, this start of the feeding operation refers to the feeding of the sheet S by the rotation of the pickup roller 501 (refer to
When the feeding operation is started (STEP S6), again the air-blow stop determination process is performed (STEP S7), and the control unit 100 judges whether or not the feeding of, for example, 15 sheets, which is the required number of sheets, has been completed (STEP S8). For example, in a case where the feeding of the 15 sheets of the sheet S has not been completed (STEP S8: No), the feeding operation is continued while repeating the air-blow stop determination process throughout the duration. Then, upon the completion of the feeding of, for example, the 15 sheets, which is the required number of sheets (STEP S8: Yes), the control unit 100 stops the air-blow operation (STEP S9), and, with that, ends the sheet feed control.
Next, details of the air-blow stop determination process mentioned above (STEPS S4 and S7) will be described. As illustrated in
On the other hand, in a case where the width size at the start of the job is different from the width size during the job (STEP S13: Yes), the gap D (refer to
Therefore, in the sheet feed control in the present embodiment, before the predetermined time has passed after the start of the air-blow operation (STEP S5: No), the control unit 100 recognizes that the positions of the side edge regulation plates 511 and 512 detected by the sheet width volume sensor 405 have been moved. Then, since it becomes identical to the case where the positions of the side edge regulation plates 511 and 512 do not correspond to the width size of the sheet at the start of the job (the positions of the side edge regulation plates 511 and 512 at the start of the job) (STEP S13 at STEP S4: Yes), the air-blow operation is stopped (STEP S14). Therefore, in a case where, for example, the user has moved to increase spacing between the side edge regulation plates 511 and 512, during the predetermined time in which the job is started and a preparation for starting the feeding of the sheet S is in progress, it is possible to stop the air-blow operation before starting the feeding of the sheet S. Thereby, at the time of feeding the sheets S subsequent to the feed of a first sheet, it is possible to reduce the disruption of the posture of the sheet S caused by the air-blow, and it is possible to reduce the skew of the sheet and the sheet jam.
Further, in the sheet feed control in the present embodiment, when, after the start of the feeding operation of the sheet S (STEP S6), the positions of the side edge regulation plates 511 and 512, detected by the sheet width volume sensor 405, have been moved, the control unit 100 recognizes that the positions of the size edge regulation plates 511 and 512 are different from the width size of the sheet at the start of the job (the positions of the side edge regulation plates 511 and 512 at the start of the job) (STEP S13 at STEP S7: Yes), and, then, the air-blow operation is stopped (STEP S14). Therefore, for example, in a case where the user has moved to increase the spacing of the side edge regulation plates 511 and 512 during the feeding of the sheet S after the start of feeding the sheet, it is possible to stop the air-blow operation even during the feeding of the sheet S. Thereby, after having detected the movements of the side edge regulation plates 511 and 512, when feeding subsequent sheets, it is possible to reduce the disruption of the posture of the sheet S caused by the air-blow, and it is possible to reduce the skew of the sheet and the sheet jam.
As described above, according to the sheet feed control of the present embodiment, the separation mode to feed the sheet while performing the air-blow is executed. During the execution of this separation mode, in the case where the positions of the side edge regulation plates 511 and 512 regulating the position of the sheet in the width direction are moved by, for example, such as the operation of the user, it is possible to stop the air-blow operation, and it is possible to reduce the skew of the sheet and the sheet jam.
In the present embodiment described above, it is mainly described that the width size of the sheet placed on the manual sheet feed tray 236 is detected by the sheet width volume sensor 405 at the start of job (prior to starting the air-blow operation), and the value of the sheet width volume sensor 405 is referred to as the width size at the start of job. However, it is not limited to this, and it is acceptable that the width size at the start of the job is set from the sheet size information input through the operation unit 730 and the external computer. In this case, before starting the air-blow operation, it is possible to determine that the width size of the sheet detected by the sheet width volume sensor 405 at the start of the job is different from the sheet size information. Therefore, it is also possible to determine the stoppage (interruption) of the air-blow operation before starting the air-blow operation.
Further, in the present embodiment, the sheet width volume sensor 405 is described as an example that detects the positions of the side edge regulation plates 511 and 512 in the width direction. However, it is not limited to this, and, for example, any type of device such as position sensors or encoders that can detect the positions of the side edge regulation plates 511 and 512 in the width direction can be used.
Further, in the present embodiment, as a case where the width size during the job is different from the width size at the start of the job, a case where the spacing between the side edge regulation plates 511 and 512 is increased to be larger than the width size of the sheet S is described. However, it is not limited to this, and the spacing between the side edge regulation plates 511 and 512 can be decreased to be less than the width size of the sheet S. That is, in a case where the positions of the side edge regulation plates 511 and 512 are decreased to be less than the width size of the sheet S, since it is conceivable that the sheet S curves in the width direction so as to be curled at the side edges of the sheet, similarly, the position of the sheet in the width direction is not accurately regulated by the side edge regulation plates 511 and 512. Therefore, similarly, there is the risk that the posture of the sheet may be disrupted by the air-blow operation.
Further, in the present embodiment, the positions of the side edge regulation plates 511 and 512 are detected by the sheet width volume sensor 405, and those positions are converted into the width size of the sheet placed on the manual sheet feed tray 236. However, it is not limited to this, and it is acceptable to configure the air-blow stop determination process such that, by simply comparing the positions of the side edge regulation plates 511 and 512 at the start of the job with the positions of the side edge regulation plates 511 and 512 during the job, in a case where these positions are different, the air-blow operation is stopped. Further, in this context, the positions of the side edge regulation plates 511 and 512 are equivalent to the AD value of the sheet width volume sensor 405. Therefore, by simply comparing the AD value at the start of the job with the AD value during the job, it is acceptable to configure the air-blow stop determination process such that the air-blow operation is stopped in a case where these values are different.
Further, in the present embodiment, the image forming apparatus 201 includes such as the control unit 100 and the manual sheet feed portion 235. However, it is not limited to this, and it is acceptable to configure the sheet feeding apparatus, such as the sheet feed deck 800, to include the control unit and the like. Further, the image forming apparatus is not limited to the image forming apparatus 201 of the present embodiment, and it is acceptable that the image forming apparatus refers to image forming systems including sheet feed decks.
Further, in the present embodiment, it is possible to selectively execute both the separation mode and the normal mode. However, it is not limited to this, and it is acceptable that it is possible to execute only the separation mode.
Further, in the present embodiment, the sheet size information may be input by performing an input operation through the operation unit 730. However, it is acceptable to input the sheet size information through such as, for example, the external computer via an interface. In this case, the interface becomes an input unit.
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2023-031339, filed Mar. 1, 2023, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-031339 | Mar 2023 | JP | national |
