Patent Application
20240417208
The present invention relates to a sheet feeding apparatus and an image forming apparatus having a sheet feeding apparatus, and particularly relates to a sheet feeding apparatus and an image forming apparatus for automatically detecting that a roller has been replaced when a roller unit for feeding a sheet is replaced.
Image forming apparatuses such as printers, copiers, or the like have often been configured with a feeding unit that separates and feeds sheets held in a sheet stacking unit one at a time, a conveyance unit that conveys the sheets, a sheet discharge unit that discharges sheets on which images are recorded to a discharge port, and the like. In such units, rubber rollers are often used to feed the sheets.
To improve the sheet conveyance performance, materials which are soft, and therefore wear down easily, are used for rubber rollers, and the surface of the roller is therefore worn down as the roller is used. Rollers wearing down, paper dust produced by feeding sheets adhering to the rollers, and the like lead to a drop in the sheet conveyance performance, which in turn causes a drop in the printing quality. On the other hand, the lifespans of modern image forming apparatuses are increasing, and an increasing number of products are configured such that components related to printing performance, such as rollers, can be replaced by users, maintenance workers, and the like before the image forming apparatus reaches the end of its lifespan.
Japanese Patent Laid-Open No. 2017-007758 proposes a detection method by which an image forming apparatus detects the timing at which a feed roller is to be replaced. The time from when the feed roller starts rotating to when a sheet is conveyed to a sensor provided downstream in a conveyance path is measured, and conveyance delay in the sheet is detected based on the measured time. Then, when the rate of occurrence of the detected conveyance delay in the sheet exceeds a threshold, the image forming apparatus notifies a user or the like that it is necessary to replace the feed roller.
Japanese Patent Laid-Open No. 2017-132600 discloses a technique for detecting an erroneous operation when a feed roller is replaced by a user, a maintenance worker, or the like.
After a feed roller is replaced by a user, a maintenance worker, or the like, it is necessary to cause the image forming apparatus to recognize that the feed roller has been replaced with a new roller. It is therefore necessary for the user, the maintenance worker, or the like to perform a reset operation, such as making a setting indicating that the replacement of the feed roller in the image forming apparatus is complete, through an operation panel or the like of the image forming apparatus. The timing for replacing the roller is detected, for example, by calculating the total driving amount of the roller and determining whether that value has reached a predetermined value. The value indicating the total driving amount is then initialized through the reset operation. The driving amount may be calculated by using a counter to count the number of sheets conveyed by the roller, for example.
The reset operation described above is an operation performed by an operator (a worker) such as a user, a maintenance worker, or the like. As such, it is conceivable that after replacing the feed roller with a new roller, the operator may forget to perform the reset operation for setting the feed roller as having been replaced, confirm the operations, or the like. In such a case, because the reset operation has not been performed, the image forming apparatus will determine that the feed roller still needs to be replaced, and will continue to prompt the user, the maintenance worker, or the like to replace the feed roller.
Meanwhile, in an image forming apparatus having a plurality of sheet feed ports, it is conceivable that an operator may erroneously perform a reset operation for setting the feed roller as having been replaced for a sheet feed port in which the roller has not been replaced. As a result, the image forming apparatus will be unable to correctly detect the actual usage states of the feed rollers. It is therefore desirable for the image forming apparatus to be capable of automatically and correctly detecting that a feed roller has been replaced with a new roller, without relying on reset operations performed by a user, a maintenance worker, or the like.
Having been achieved in light of the above-described past examples, the present invention realizes a sheet feeding apparatus and an image forming apparatus capable of automatically detecting that a feed roller has been replaced with a new roller, and automatically executing a reset operation without requiring a manual operation.
To achieve this, according to one aspect of the present invention, there is provided a sheet feeding apparatus comprising: a stacking unit in which a sheet-shaped recording material is stacked; a sheet surface detection member capable of taking on one of a first state, in which the sheet surface detection member displaces in accordance with a height of a top surface of the recording material, and a second state; a detector configured to detect the sheet surface detection member; a feeding unit capable of being mounted in and removed from a main body of the sheet feeding apparatus, the feeding unit including a feed roller that conveys the recording material and a switching unit that switches the sheet surface detection member to one of the first state and the second state; and a controller, wherein the switching unit switches the sheet surface detection member to the second state in response to the feeding unit being replaced, and the controller is configured to detect that the feeding unit has been replaced based on a state change detected by the detector.
According to another aspect of the present invention, there is provided a sheet feeding apparatus comprising: a stacking unit in which a sheet-shaped recording material is stacked; a sheet surface detection member capable of taking on one of a first state, in which the sheet surface detection member displaces in accordance with a height of a top surface of the recording material, and a second state; a detector configured to detect the sheet surface detection member; a driving unit for being attached to and driving a removable feeding unit, the feeding unit including a feed roller that conveys the recording material and a switching unit that switches the sheet surface detection member to one of the first state and the second state; and a controller, wherein the switching unit switches the sheet surface detection member to the second state in response to the feeding unit being replaced, and the controller is configured to detect that the feeding unit has been replaced based on a state change detected by the detector.
According to still another aspect of the present invention, there is provided a sheet feeding apparatus comprising: a removable stacking unit in which a sheet-shaped recording material is stacked; a sheet feeding part detector configured to detect a state indicating whether the stacking unit is mounted or removed; a recording material detector configured to detect the recording material stacked in the stacking unit; a sheet surface detection member capable of taking on one of a first state, in which the sheet surface detection member displaces in accordance with a height of a top surface of the recording material, and a second state; a sheet surface detector configured to detect the sheet surface detection member; a feeding unit capable of being mounted in and removed from a main body of the sheet feeding apparatus, the feeding unit including a feed roller that conveys the recording material and a switching unit that switches the sheet surface detection member to one of the first state and the second state; and a controller, wherein the switching unit switches the sheet surface detection member to the second state in response to the feeding unit being replaced, and the controller is configured to detect that the feeding unit has been replaced based on history information indicating mounting and removal of the stacking unit detected by the sheet feeding part detector, when output of the sheet surface detector indicates that the recording material is at a height at which the recording material can be conveyed and output of the recording material detector indicates that the recording material is not present.
According to yet another aspect of the present invention, there is provided a sheet feeding apparatus comprising: a removable stacking unit in which a sheet-shaped recording material is stacked; a recording material detector configured to detect the recording material stacked in the stacking unit; a sheet surface detection member capable of taking on one of a first state, in which the sheet surface detection member displaces in accordance with a height of a top surface of the recording material, and a second state; a sheet surface detector configured to detect the sheet surface detection member; a feeding unit capable of being mounted in and removed from a main body of the sheet feeding apparatus, the feeding unit including a feed roller that conveys the recording material and a switching unit that switches the sheet surface detection member to one of the first state and the second state; and a controller, wherein the switching unit is configured to switch the sheet surface detection member to the second state in response to the feeding unit being replaced, and switch the sheet surface detection member from the second state to the first state in response to the feed roller being driven, and the controller is configured to drive the feed roller and switch the sheet surface detection member to the first state using the switching unit in response to a conveyance instruction, when the sheet surface detector detects that the recording material is at a height at which the recording material can be conveyed and the recording material detector detects that the recording material is present, and then, after the sheet surface detector detects that the recording material is not at a height at which the recording material can be conveyed, determine that the feeding unit has been replaced.
According to still another aspect of the present invention, there is provided a sheet feeding apparatus comprising: a removable stacking unit in which a sheet-shaped recording material is stacked; a sheet feeding detector configured to detect a state indicating whether the stacking unit is mounted or removed; a recording material detector configured to detect the recording material stacked in the stacking unit; a sheet surface detection member capable of taking on one of a first state, in which the sheet surface detection member displaces in accordance with a height of a top surface of the recording material, and a second state; a sheet surface detector configured to detect the sheet surface detection member; a feeding unit capable of being mounted in and removed from a main body of the sheet feeding apparatus, the feeding unit including a feed roller that conveys the recording material and a switching unit that switches the sheet surface detection member to one of the first state and the second state; and a controller, wherein the switching unit switches the sheet surface detection member to the second state in response to the feeding unit being replaced, the controller is configured to, when the sheet feeding part detector detects that the stacking unit has been removed, start measuring a time in response to the sheet surface detector detecting that a state of the recording material has changed from a height at which the recording material cannot be conveyed to a height at which the recording material can be conveyed, and stop measuring the time in response to the recording material detector detecting that a state in which the recording material is not present has changed to a state in which the recording material is present, and determine that the feeding unit has been replaced when the measured time is not less than or equal to a threshold time.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made to an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.
A first embodiment of the present invention will be described in detail hereinafter with reference to the drawings. In particular, an image forming apparatus, and a sheet feeding apparatus which feeds cut sheets, which are a sheet-shaped recording material, from a sheet feed cassette, and which is included in the image forming apparatus, will be described.
A sheet feeding section 31 includes a pickup roller 32, which feeds out an uppermost sheet S1 of the sheet bundle Sa stacked in the sheet feed cassette 11 serving as a stacked means, and a separation roller pair 33 which separates the sheet S fed out by the pickup roller 32. The separation roller pair 33 is constituted by a feed roller 34 and a retard roller 35. Furthermore, a conveyance roller 36 is provided to convey the sheets S, which are separated and fed one at a time from the sheet bundle Sa by the separation roller pair 33, to an image forming section 21. The pickup roller 32 and the feed roller 34 are included in a feeding unit 40 which can be removed from the apparatus main body, and when components such as the pickup roller 32 are worn out, the feeding unit 40 as a whole is replaced. The pickup roller 32 and the feed roller 34 may be called “feed rollers” individually or collectively.
The image forming section 21 is a unit that forms images using an electrophotographic method. The image forming section 21 includes a photosensitive drum 22 that forms a toner image, a transfer roller 23 that transfers the toner image formed on the photosensitive drum 22 onto a sheet S fed from the sheet feed cassette 11, and the like. A fixing unit 24 is provided downstream from the image forming section 21, which fixes the toner image onto the sheet S by applying heat and pressure to the sheet S onto which the toner image has been transferred, thereby forming an image. To form a full-color image, the LBP 1 includes, as photosensitive drums 22, photosensitive drums 22Y, 22M, 22C, and 22K, which form toner images of yellow, magenta, cyan, and black color components, respectively.
The sheet S on which an image has been formed is discharged, by a sheet discharge roller 25, to a sheet discharge section 26 provided in an upper part of the apparatus.
The sheet surface lever 50 is configured including a detection end 50a, which is an end part on the feeding unit 40 side, a flag part 50b, which is an end part on the opposite side, and a rotation support point 50c in the center thereof. When in a freely-movable state, the sheet surface lever 50 may be biased about the rotation support point 50c in what is the counterclockwise direction in
The sheet surface sensor 52 is a photointerrupter including a light-emitting unit 52a that emits light 53 and a light-receiving unit 52b that receives the light 53 emitted from the light-emitting unit 52a, and is a light detection sensor. The sheet surface sensor 52 detects a light-blocking state in which the flag part 50b of the sheet surface lever blocks the light 53 from the light-emitting unit 52a, or a light-transmissive state in which the light 53 from the light-emitting unit 52a is not blocked. In the present embodiment, control is performed such that the light-transmissive state is determined to be a state in which the height of the top surface of the sheet bundle Sa is a height at which feeding is not possible, whereas the light-blocking state is determined to be a state in which the height of the top surface of the sheet bundle Sa is a height at which feeding is possible. However, the embodiment is not limited thereto. Control may be performed such that the light-transmissive state is determined to correspond to a height at which feeding is possible. In this manner, the states indicated by a light-blocking state and a non-light-blocking state can be switched. In the present embodiment, the light-blocking state may be called a “feed-capable state” or a “first state”, and the non-light-blocking state (the light-transmissive state) may be called a “feed-incapable state” or a “second state”.
As illustrated in
When the sheet bundle Sa is set in the sheet feed cassette 11, the pickup roller 32 contacts the uppermost sheet, as illustrated in
The detailed configuration and operations of the feeding unit 40 according to the present invention will be described next in detail.
In addition to the feeding holder 301, feed roller 34, pickup roller 32, and sheet surface detection plate 306, the feeding unit 40 includes an idler gear 302, a holding member 307, and a biasing spring 320. The feeding holder 301 has hollow shaft pairs F301a and F301b, and R301a and R301b, which are opposite to each other and have a common axis line. The feed roller 34 has a shaft 34a and a shaft 34b at opposite ends. The outer surface of the shaft 34a and the inner surface of the hollow shaft F301a, and the outer surface of the shaft 34b and the inner surface of the hollow shaft F301b, are fitted to each other and attached so as to enable free rotation. Likewise, the pickup roller 32 has a shaft 32a and a shaft 32b at opposite ends. The outer surface of the shaft 32a and the inner surface of the hollow shaft F301a, and the outer surface of the shaft 32b and the inner surface of the hollow shaft F301b, are fitted to each other and attached so as to enable free rotation.
The one shaft 34a and the shaft 32a of the feed roller 34 and the pickup roller 32, respectively, have a gear part 34c and a gear part 32c in a part of the outer surfaces thereof, and each of the gear parts meshes with the idler gear 302. When the feed roller 34 is driven, the pickup roller 32 is driven via the idler gear 302. The sheet surface detection plate 306 has a hole 306a and a hole 306b, which engage with the outer surface of the shaft R301a and the outer surface of the shaft R301b of the feeding holder 301, respectively, and is attached so as to be freely rotatable about the shaft R301a and the shaft R301b.
The holding member 307 is attached so as to be freely rotatable by fitting a hole 307a thereof to the outer surface of the shaft R301a of the feeding holder. The biasing spring 320 illustrated in
The feeding holder 301 includes an engaging part 301e that engages with the hook part 307b, and can be engaged by rotating the holding member 307 in what is the counterclockwise direction in
As the arm 307d is pushed up, the amount by which the hook part 307b hangs on the engaging part 301e decreases, and when the amount of hang reaches 0, the holding member 307 is rotated by the biasing force of the biasing spring 320. The rotation stops when the protruding part 307c collides with a part of the feeding holder 301, producing a state such as that illustrated in
Operations for detecting the replacement of the feeding unit will be described next.
When removing the feeding unit 40 from the sheet feed cassette 11, the opposite sequence from that described above is performed. First, from the state illustrated in
Note that when the feeding unit 40 is to be replaced, the middle plate 120 is lowered in advance. This operation may be performed in response to an operator manipulating a switch or the like, for example. Alternatively, the image forming apparatus may be controlled such that when a door in a housing is opened in order to replace the feeding unit 40, a sensor or the like detects the door being opened, and the middle plate 120 is lowered in accordance with the detection result.
Here, when the feed shaft 332 is rotated and the feed roller 34 is driven, the holding member 307 operates as described earlier with reference to
The control unit provided in the image forming apparatus 1 determines that the roller (i.e., the feeding unit 40) has been replaced in response to the output of the sheet surface sensor 52 changing from the light-blocking state to the light-transmissive state after the roller has been driven. The first light-blocking state in this case is the state illustrated in
The control unit then rotates the lift arm 121, lifts the middle plate 120 and the sheet bundle Sa stacked thereon, and stops when the sheet surface sensor 52 senses that the state has changed to the light-blocking state again. In this state, the pickup roller 32 is in contact with the uppermost sheet S1. This completes preparations for the start of feeding of the uppermost sheet S1 from the sheet bundle Sa.
If the feeding unit 40 has not been replaced, the holding member 307 stays in the retracted position, rather than being in the operating position. Accordingly, the output of the sheet surface sensor 52 indicates the non-light-blocking state before and after the driving of the feed roller 34.
Thus, in the present embodiment, when the feeding unit 40 is replaced, the holding member 307 of the new feeding unit 40 is in the operating position, and the sheet surface sensor 52 is therefore in the light-blocking state. When the feed roller is driven thereafter, the holding member 307 moves to the retracted position, and the sheet surface sensor 52 enters the non-light-blocking state. The control unit determines that the feeding unit 40 has been replaced based on this state change, and resets the value of the counter that counts the conveyed number of sheets to 0. The lifter part 13 is then raised, and images can be formed.
The counter 1111 is checked periodically during the printing control sequence, or is checked as needed to see whether the value thereof exceeds a predetermined value. If the value thereof exceeds the predetermined value, a message indicating that the feeding unit 40 is to be replaced is output from a display unit, a speaker, or the like provided in the main body of the image forming apparatus 1. Alternatively, the message may be output to a host apparatus connected to the image forming apparatus 1.
Upon returning to the standby state, first, the signal from the sheet surface sensor 52 is checked to determine whether the sheet surface has been detected (step S1201). If the sheet surface is not detected, i.e., if the sheet surface sensor 52 is in the non-light-blocking state, it is determined that the feeding unit 40 has not been replaced. The sequence branches to step S1205, where the lifter part 13 is raised in preparation for the subsequent printing control.
On the other hand, if in step S1201 the sheet surface is detected, i.e., the sheet surface sensor 52 is in the light-blocking state, the feed shaft driving motor 1104 drives by a set amount to feed a sheet in the conveyance direction (step S1202). The set amount may be any driving amount sufficient for the holding member 307 to move about the shaft from the operating position illustrated in
The replacement of the feeding unit 40 can be detected, and the counter can be reset, through the configuration and control described above. With this sequence, a worker does not need to reset the counter, and a manager or the like can therefore be notified of the timing for replacing the feeding unit immediately.
In the present embodiment, the counter which counts the number of sheets that have passed is reset as the operation performed after the roller replacement determination, but the configuration is not limited thereto. For example, a warning may be cleared, a notification may be issued to a user or a maintenance worker, or the like.
As described above, the present embodiment makes it possible to automatically detect that a feeding unit has been replaced.
A second embodiment of the present invention will be described next. Parts that are the same as in the first embodiment will not be described here.
The sheet surface lever 60 according to the present embodiment has a shape in which a slit 60d is provided in a part of a light-blocking surface 60b that blocks the light from the sheet surface sensor 52. The range indicated by “L” corresponds to an upper part of the light-blocking part, the range indicated by “M” corresponds to a lower part of the light-blocking part, and the range indicated by “N” is an area outside of the light-blocking part. The design is such that in a state in which a lifting surface 60c of the sheet surface lever 60 is lifted up by the support part 307f of the holding member 307, the range indicated by “L” is irradiated with the light 53 emitted from the light-emitting unit 52a of the sheet surface sensor 52. Furthermore, the design is such that in a state where the height of the uppermost sheet S1 of the sheet bundle Sa can be detected, the range indicated by “M” is irradiated with the light 53 from the sheet surface sensor 52 when the sheet bundle Sa is in an overloaded state, where the loading height of the sheet bundle Sa exceeds the permissible height for the sheet feed cassette 11. When the height of the uppermost sheet S1 is at a position lower than the height at which sheets can be conveyed by the pickup roller 32, the range indicated by “N” is irradiated with the light 53 from the sheet surface sensor 52.
When not in the overloaded state, the sheet bundle Sa is lifted by the middle plate 120 as a feed preparation operation. At this time, as the sheet bundle Sa rises, the irradiation position of the light 53 approaches the lower end of the range indicated by “M”. The height when the light 53 changes from the light-transmissive state to the light-blocking state at the lower end of the range indicated by “M” is recognized as a height at which sheets can be fed, and the rising of the middle plate is stopped. On the other hand, when in the overloaded state, the range indicated by “M” is irradiated by the light 53 prior to the sheet bundle Sa being lifted by the middle plate 120. A determination sequence which uses a combination of the loading state of the sheet bundle Sa and whether or not the roller has been replaced will be described next.
When Roller is Replaced when not in Overloaded State
Because the roller is replaced, the range indicated by “L” is irradiated with the light 53 from the sheet surface sensor 52. Here, when the feed roller 34 is driven, the holding member 307 retracts. In response, the sheet surface lever 60 rotates in one direction within the operating range thereof, from the retracted position to a position where the range indicated by “N” is irradiated by the light 53 from the sheet surface sensor 52. The slit 60d is passed at this time, and thus the signal from the sheet surface sensor 52 switches three times, namely, from the light-blocking state, to the light-transmissive state, to the light-blocking state, and back to the light-transmissive state.
When such a signal change resulting from multiple changes between the light-blocking state and the light-transmissive state is detected, the control unit determines that the roller has been replaced and the loading state of the sheet bundle Sa is within a normal range. Accordingly, in this case, the counter 1111 is reset.
When Roller is Replaced when in Overloaded State
Similarly, because the roller is replaced, the range indicated by “L” is irradiated with the light 53 from the sheet surface sensor 52. The feed roller 34 is driven and the sheet surface lever 60 rotates, but because the state is the overloaded state, the rotation of the sheet surface lever 60 stops at a position where the range indicated by “M” is irradiated by the light 53 from the sheet surface sensor 52. At this time, the signal from the sheet surface sensor 52 switches twice, namely, from the light-blocking state, to the light-transmissive state, and back to the light-blocking state.
When such a signal change is detected, the control unit determines that the roller has been replaced and that the loading state of the sheet bundle Sa is the overloaded state, in which the sheet bundle exceeds the height at which sheets can be fed. Accordingly, in this case, the counter 1111 is reset. Furthermore, when the overloaded state is detected, the user is notified to that effect.
When Roller is not Replaced when in Overloaded State
Because the roller has not been replaced, a detection end 60a of the sheet surface lever 60 is in contact with the sheet surface detection plate 306. Additionally, because the sheet bundle Sa is in the overloaded state, the range indicated by “M” is irradiated by the light 53 from the sheet surface sensor 52. Even if the feed roller 34 is driven, the sheet surface lever 60 does not rotate and remains in place. At this time, the signal from the sheet surface sensor 52 does not change from the light-blocking state.
When such a signal is detected, the control unit determines that the roller has not been replaced, and the loading state of the sheet bundle Sa is the overloaded state. In this case, the user is notified that the overloaded state has been detected.
When Roller is not Replaced when not in Overloaded State
Because the roller has not been replaced and the state is not the overloaded state, the range indicated by “N” is irradiated by the light 53 from the sheet surface sensor 52. At this time, the control unit determines that the uppermost sheet S1 is at a position lower than the height at which sheets can be fed, and therefore rotates the lift arm 121 to lift the sheet bundle Sa. The rotation of the lift arm 121 is stopped once the sheet surface sensor 52 changes to the light-blocking state, which completes the preparations for starting the feeding of the sheet S1.
In the first embodiment, the position of the sheet surface lever 50 is stable both in the position indicated in
As described above, according to the present embodiment, whether the roller has been replaced and whether the state is an overloaded state can both be determined using only the sheet surface lever 60 and the sheet surface sensor 52.
A third embodiment will be described next.
The rotation flag 401 includes a light-blocking part 401c, and is capable of switching the light 53 between the light-blocking state and the light-transmissive state.
The sheet bundle Sa is then lifted by the middle plate (not shown). As illustrated in
If the roller has not been replaced, the state is the state illustrated in
As described above, according to the present embodiment, the configuration is such that the flag which detects the height of the sheet surface also functions as a switching means, which makes it possible to automatically determine whether the roller has been replaced using fewer components.
Although the foregoing first to third embodiments have been described using a feeding unit of an LBP, the present invention is not limited thereto. The present invention can be similarly applied in an optional sheet conveyance apparatus or the like. Furthermore, the image forming apparatus is not limited to an electrophotographic apparatus, and the present invention can also be applied in an ink jet image forming apparatus and the like, for example.
A fourth embodiment of the present invention will be described in detail hereinafter with reference to the drawings. In particular, an image forming apparatus, and a sheet feeding apparatus which feeds cut sheets, which are a sheet-shaped recording material, from a sheet feed cassette, and which is included in the image forming apparatus, will be described.
In the image forming apparatus illustrated in
The CPU 1001 drives the pickup roller 32 and the feed roller 34 by operating the I/O port 1006 over the bus 1005. Additionally, by accessing the output values from the sensors at the I/O port 1006 over the bus 1005, the CPU 1001 confirms the states of the detected items indicated by the sheet surface sensor 52, the sheet presence sensor 37, and the cassette sensor 39.
Note the
A sheet feed control unit 1510 performs lift-up control when a cassette presence detection unit 1513 detects that the cassette 11 is present using the cassette sensor 39. A lifter driving unit 1511 instructs the lift driving motor 1021 to drive, which raises and lowers the lift arm 121. A roller driving unit 1512 instructs the roller driving motor 1022 to drive, which causes the feed roller 34 and the pickup roller 32 attached to the feed shaft 332 to rotate. Furthermore, the rotation of the feed roller 34 and the idler gear 302 causes the state of the sheet surface lever 50 to switch. A sheet surface detection unit 1514 detects whether the sheet is at a height at which the sheet can be fed, according to the light-blocking state or the light-transmissive state detected by the sheet surface sensor 52. In this example, if the state is the light-blocking state, the sheet is determined to be at a height at which the sheet can be fed.
A sheet presence detection unit 1515 uses the sheet presence sensor 37 to detect whether the sheet bundle Sa is present. A first new product determination control unit 1540 determines whether the feeding unit 40 is new based on detection results from the cassette sensor 39, the sheet surface sensor 52, and the sheet presence sensor 37. The first new product determination control unit 1540 also determines whether the feeding unit 40 is new based on a detection result from the sheet surface sensor 52 after a lifter part 13 has been lowered (lifted down) by the lifter driving unit 1511. The first new product determination control unit 1540 also detects and makes a notification that the sheet bundle Sa is not present, and detects and makes a notification that the feeding unit 40 has malfunctioned, based on the detection results from the cassette sensor 39, the sheet surface sensor 52, and the sheet presence sensor 37.
A method by which the first new product determination control unit 1540 determines whether the feeding unit 40 is new will be described next with reference to
In the state illustrated in
Assuming the state illustrated in
It is sufficient to store the detection states of the cassette sensor 39, which indicate that the sheet feed cassette 11 was opened immediately before checking the sheet surface sensor 52 and the sheet presence sensor 37, as the opening/closing history.
Immediately after the sheet feed cassette 11 has been opened or closed, the sheet surface sensor 52 in
However, if the feeding unit 40 is replaced with a new unit and the sheet feed cassette 11 is opened and closed while the power is off, the CPU 1001 cannot store an indication that the sheet feed cassette 11 has been opened and closed in the RAM 1004. Accordingly, in the sequence described above, whether the state is that illustrated in
When the feeding unit 40 is determined to be new, a switching operation for disengaging the support part 307f of the holding member 307 from the lifting surface 50c of the sheet surface lever is performed by rotating the pickup roller 32. The sheet surface sensor 52 continuing to detect the light-blocking state despite the switching operation having been performed indicates that the feeding unit 40 is not connected correctly, and a malfunction is determined to have occurred. In such a case, a notification is made via the controller 1501.
In the case of mechanism in which the lift arm 121 can descend, the unit may be determined to be new when a lift-down instruction is made and the sheet surface sensor 52 switches from the light-blocking state to the light-transmissive state.
The cassette presence detection unit 1513 detects whether the cassette 11 is closed (step S1701). If the cassette 11 is open, history information indicating that there is opening/closing history of the cassette 11 is stored in an opening/closing storage part of the RAM 1004 (step S1702). If the cassette sensor 39 detects that the cassette 11 has been closed, it is determined whether the sheet surface sensor 52 is in the light-blocking state (step S1703). If the sheet surface sensor 52 is determined to be in the light-blocking state, it is determined whether the sheet presence sensor 37 detects that no sheet bundle Sa is stacked (step S1704). If it is determined that the sheet presence sensor 37 detects that no sheet bundle Sa is stacked, the history information of the sheet feed cassette stored in step S1702 is accessed to obtain the opening/closing history (step S1705).
If it is determined in step S1705 that the sheet feed cassette being opened is stored in the opening/closing history, the feeding unit 40 is determined to be new (step S1706). In step S1706, a counter for estimating the replacement timing of the feeding unit 40 is reset to 0, for example. This counter is incremented by 1 each time a sheet is fed, for example, and when a predetermined value is reached, a message indicating that it is time for the feeding unit 40 to be replaced is output to the user. Furthermore, when the feeding unit 40 is determined to be new, the switching operation for disengaging the support part 307f of the holding member 307 from the lifting surface 50c of the sheet surface lever is performed by driving the pickup roller 32 (step S1708).
After performing the switching operation in step S1708, whether the sheet surface sensor 52 is in the light-transmissive state (the non-light-blocking state) is detected (step S1709). If the sheet surface sensor 52 is in the light-blocking state in step S1709, the feeding unit 40 is determined to have malfunctioned (step S1710). In step S1710, for example, the state of the image forming apparatus is shifted from a printing standby state to an error state, where printing is not possible until the malfunction is rectified, and a message is output to the user. The opening/closing storage part is then reset or cleared (step S1711). The initial value may be any value as long as the value does not indicate that the sheet feed cassette 11 is open. Step S1706 may be performed after the sheet surface sensor 52 is detected to be in the light-transmissive state in step S1710.
If the sheet surface sensor 52 is in the light-transmissive state in step S1709, the opening/closing storage part is reset (step S1711). The processing performed by the first new product determination control unit 1540 ends thereafter. When the sheet surface sensor 52 is in the light-blocking state in step S1703 and when the sheet presence sensor 37 detects that the sheet bundle Sa is present in step S1704, the opening/closing storage part is reset (step S1711) and the processing by the first new product determination control unit 1540 ends.
If the sheet feed cassette being opened is not stored in the opening/closing history in step S1705, the user is notified via the controller 1501 that there is no sheet bundle Sa, or the user is prompted to refill the sheets (step S1707). The opening/closing storage part is then reset (step S1711).
As described above, according to the present embodiment, sheet feeding operations are not performed when the feed roller is replaced with a new unit and the sheet cannot be detected by the sheet presence sensor in the cassette. Determining that the feeding unit is new based on the opening/closing history of the cassette without performing sheet feeding operations makes it possible to prevent the feed roller from being worn down.
A fifth embodiment of the present invention will be described next. The present embodiment will describe control for determining that the feeding unit is new when the sheet surface sensor 52 is in the light-blocking state and the sheet presence sensor 37 detects a sheet in the cassette, without feeding sheets unnecessarily. Note that parts that are the same as in the first embodiment will not be described here.
A hardware block diagram according to the present embodiment will be described first with reference to
The CPU 1001 drives the conveyance roller 36 by operating the I/O port 1006 over the bus 1005. Additionally, by accessing the I/O port 1006 over the bus 1005, the CPU 1001 confirms the value of the signal output from the conveyance sensor 38.
The functional configuration of the present fifth embodiment will be described next with reference to
A conveyance detection unit 1520 detects that a sheet is being conveyed, using the conveyance sensor 38. A second new product determination control unit 1550 determines whether the feeding unit 40 is new based on detection results from the conveyance sensor 38, the sheet surface sensor 52, and the sheet presence sensor 37. Additionally, after rotating the feed roller 34 using the roller driving unit 1512, the second new product determination control unit 1550 detects and makes a notification as to whether there is a paper jam, based on the detection result from the conveyance sensor 38.
A method by which the second new product determination control unit 1550 determines whether the feeding unit 40 is new will be described next with reference to
In
Accordingly, whether the feeding unit 40 is new is determined by using the driving of the pickup roller 32 for detecting the new feeding unit 40, which is performed through the sheet feeding operations during printing. Assume that the sheet feeding operations are performed when printing is started, and the pickup roller 32 attempts to feed a sheet. In the case illustrated in
The engine control unit 1000 determines whether the sheet surface sensor 52 is in the light-blocking state (step S1901). If the sheet surface sensor 52 is detected as being in the light-blocking state, whether the sheet bundle Sa is present, detected by the sheet presence sensor 37, is determined (step S1902). If the sheet presence sensor 37 determines that the sheet bundle Sa is detected, printing is started in response to a print instruction made by the controller 1501 (step S1903). Here, the print instruction is a conveyance instruction. The pickup roller 32 is driven to feed the uppermost sheet S1 of the sheet bundle (step S1904).
After step S1904, whether a sheet is present in the conveyance path is determined by the conveyance sensor 38 (step S1905).
If the sheet is not detected within a predetermined length of time in step S1905, it is determined whether the sheet surface sensor 52 is in the light-transmissive state (step S1906). If the sheet surface sensor 52 is determined to be in the light-transmissive state, the feeding unit 40 is determined to be new (step S1907). In step S1907, a counter for estimating the replacement timing of the feeding unit 40 is reset to 0, for example. This is the same as in the first embodiment. Furthermore, lift-up control is performed until the sheet surface sensor 52 changes to the light-blocking state (step S1908). Once the lift-up ends, the printing started in step S1903 is continued. If the sheet surface sensor 52 is in the light-blocking state before the lift-up control is performed in step S1907, the sheet surface detection plate 306 is determined to be pushed up due to a paper jam near the feeding unit 40, and a notification indicating the jam is made (step S1909).
When a sheet is detected is step S1905, the processing of
As described above, according to the present embodiment, when the feed roller is replaced with a new unit and a sheet in the cassette is detected by the sheet presence sensor, the feeding unit can be determined to be new based on the result of the conveyance sensor detecting a sheet. This makes it possible to detect a new unit utilizing operations that drive the pickup roller when feeding sheets during normal printing operations, which in turn makes it possible to prevent sheets from being fed unnecessarily due to new sheets being detected outside the printing operations.
A sixth embodiment of the present invention will be described next. The present embodiment will describe control for detecting whether the cassette is in the overloaded state, even in a configuration where the sheet surface sensor is put into the light-blocking state when the feeding unit is new. Here, the “overloaded state” is a state where the loading height of the sheet bundle in the cassette exceeds the permissible height for the cassette. Note that parts that are the same as in the first embodiment will not be described here.
The hardware configuration according to the present embodiment is the same as in the fourth and fifth embodiments and will therefore not be described.
The functional configuration of the present embodiment will be described next with reference to
A method for distinguishing whether the sheet feed cassette 11 is in the overloaded state through overload determination control will be described next with reference to
Accordingly, the overloaded state is determined based on a change in the detection result from the sheet surface sensor 52 and the detection result from the sheet presence sensor 37 up until the cassette 11 is closed.
In
Accordingly, the time from when the sheet surface sensor 52 switches from the light-transmissive state to the light-blocking state to when the sheet presence sensor 37 detects that there is no sheet is compared to the time when the sheet presence sensor 37 detects that there is a sheet. The measurement of this time starts when the sheet surface sensor 52 switching from the light-transmissive state to the light-blocking state is detected, and the time until the sheet presence sensor 37 switches from not detecting a sheet to detecting a sheet is measured. Note that the conditions for starting and ending the measurement may be reversed in accordance with the positional relationship between the sheet surface sensor 52 and the sheet presence sensor 37. In other words, if the sheet bundle Sa is first detected by the sheet presence sensor 37 when the sheet feed cassette 11 is inserted, the conditions for starting and ending the measurement may be reversed from the order described above. When the cassette sensor 39 detects that the cassette 11 has been closed, the overloaded state is distinguished out by comparing the measured time with a threshold time used for the overload determination. Assuming the distance from the position of the sheet surface sensor 52 to the position of the sheet presence sensor 37 is 50 mm and the speed at which the user closes the cassette 11 is 100 mm/sec, the threshold time is set to 500 msec. Although the threshold time is set as described above in the present embodiment, the configuration and the speed at which the user closes the cassette 11 may be changed, or a setting time may be defined by adding a margin for determining whether the cassette is overloaded.
The engine control unit 1000 determines that the sheet surface sensor 52 switches from the light-transmissive state to the light-blocking state (step S2101). When the change in the state of the sheet surface sensor 52 is detected in step S2101, the timer 1002 begins measuring the time (step S2102). In step S2101, the state of the sheet surface sensor 52 is monitored at regular intervals, e.g., until the state of the sheet surface sensor 52 changes from the light-transmissive state to the light-blocking state.
Whether the sheet has been detected by the sheet presence sensor 37 while the time is being measured is determined (step S2103). The time measurement ends when the sheet presence sensor 37 detects the sheet in step S2103 (step S2104). In step S2103, the state of the sheet presence sensor 37 is monitored at regular intervals, e.g., until the sheet presence sensor 37 detects the sheet. After the time measurement ends, the measured time is compared with the predetermined threshold time mentioned above (step S2105).
If the measured time is no greater than the threshold time, the sheet bundle Sa is determined to be in the overloaded state (step S2106). When the sheet bundle is determined to be overloaded, the user may be notified of the overloaded state via the controller 1501. If the measured time exceeds the threshold time, the feeding unit 40 is determined to be new, and the control ends. In this case, a counter value for estimating the replacement timing of the feeding unit 40 may be reset to 0.
As described above, according to the present embodiment, even in a configuration where the sheet surface sensor is put into a light-blocking state when the feeding unit is new, the overloaded state can be determined from the detection results of the sheet surface sensor and the sheet presence sensor when the cassette is closed. This makes it possible to determine the overloaded state even when the sheet surface sensor is used to detect new units.
According to all the above-described embodiments, the feeding unit 40 being replaced can be determined automatically, and the user can be accurately notified of the timing for replacing the feeding unit 40.
Although the foregoing six embodiments have been described using a feeding unit of an LBP, the present invention is not limited thereto. The present invention can be similarly applied in an optional sheet conveyance apparatus or the like. Furthermore, the image forming apparatus is not limited to an electrophotographic apparatus, and the present invention can also be applied in an ink jet image forming apparatus and the like, for example.
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. 2023-097910, filed Jun. 14, 2023, Japanese Patent Application No. 2023-103597, filed Jun. 23, 2023 which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-097910 | Jun 2023 | JP | national |
| 2023-103597 | Jun 2023 | JP | national |
