JP3583096B2 - Sheet feeding device and image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeding apparatus mounted on an image forming apparatus (hereinafter, simply referred to as an “image forming apparatus”) such as a copier, a printer, a facsimile, and the like. The present invention relates to an automatic sheet feeding apparatus detachably configured in an image forming apparatus including an aligning unit that supplies the sheet to the image forming unit while aligning the sheet with the sheet.
[0002]
[Prior art]
The image forming apparatus includes a feeding unit for feeding the stacked and stored sheets and an image forming unit for forming a character or a graphic on the sheet fed from the feeding unit. The sheet is conveyed from a feeding unit to an image forming unit in a sheet conveying path provided in the image forming apparatus.
[0003]
In such an image forming apparatus, in order to improve image forming quality by forming an image at a predetermined position on a sheet, a side edge of the sheet fed from a feeding unit is transported in order to accurately position the sheet. 2. Description of the Related Art An image forming apparatus provided with an aligning unit that supplies an image to an image forming unit while aligning the image forming unit with a reference has been put to practical use. An example of an image forming apparatus provided with such an aligning means is disclosed in JP-A-8-20807 (US Pat. No. 5,494,277).
[0004]
The apparatus described in this publication has a built-in cassette tray for storing sheets in the image forming apparatus, and is configured to supply sheets stacked in the cassette tray to the image forming unit side. The number of sheets stored in such a cassette tray is usually about 250 to 500 sheets. When performing image formation processing in a large amount and at high speed, frequent sheet replenishment is required. Therefore, an automatic feeding device capable of storing a large number of sheets is required.
[0005]
As described in Japanese Patent No. 2625057 (U.S. Pat. No. 5,368,285), such a large-capacity automatic feeding apparatus is capable of supporting a large number (generally, about 2,000 to 3,000) of laminated sheets and moving the paper up and down. The apparatus includes a deck (support table) and separation / supply means for separating sheets stacked on the paper deck one by one and supplying the sheets to registration rollers on the image forming apparatus side.
[0006]
Japanese Patent Application Laid-Open No. 11-30884 discloses an apparatus incorporated in an image forming apparatus, which separates the rollers of an upstream pair of registration rollers after a sheet reaches a downstream conveying roller, thereby forming a downstream side of the conveying path. Discloses an example that attempts to reduce the transport load during transport of the rollers arranged in the printer. The separation of the pair of registration rollers is performed by attaching one of the rollers to a swinging lever and moving the lever by a solenoid.
[0007]
[Problems to be solved by the present invention]
However, when such a conventional large-capacity automatic sheet feeding apparatus is mounted on an image forming apparatus provided with the above-mentioned aligning means, there are some problems.
[0008]
First, after the sheet arrives at the aligning means on the image forming apparatus side from the automatic sheet feeding apparatus, the sheet is moved in a direction intersecting the sheet transport direction along the transport reference. When the sheet was nipped by the separation / feeding means, the sheet could not move smoothly to the sheet conveyance reference side. In particular, when the conveying force of the aligning means is increased, the conveying reference may be exceeded, or in the case of a thin sheet, the side edges of the sheet may buckle. Could not.
[0009]
Secondly, it is conceivable to arrange the sheet conveyance reference and the aligning means on the image forming apparatus side on the automatic sheet feeding apparatus side. In this case, however, the mechanism of the sheet feeding apparatus becomes complicated and the apparatus becomes inconvenient. Upsizing was inevitable.
[0010]
Third, the sheet feeding apparatus needs to provide an aligning means because the image forming apparatus has been performing a resist correction for aligning the leading edge of the fed sheet after the separation feeding. The image forming apparatus main body had to be enlarged. Therefore, if the registration means is deleted, the sheet must be corrected only by the aligning means.In the case of a sheet fed with a large skew angle, the alignment may not be corrected properly. Had occurred.
[0011]
The present invention appropriately controls a nip state of a sheet so that a reference position of a sheet is surely adjusted by an aligning means in a sheet feeding device configured to be detachable from an image forming apparatus having an aligning means. It is an object of the present invention to provide a sheet feeding device having the above configuration.
[0012]
Further, the present invention further provides a sheet feeding apparatus which feeds a sheet from the sheet separation feeding means to the registration roller means, or performs a registration correction in the registration roller means and sends the sheet to the downstream side. To provide a sheet feeding device capable of high-speed and high-efficiency sheet feeding by appropriately performing sheet feeding or conveyance driving in association with control of a sheet nip state or a sheet opening state in these means. With the goal.
[0013]
[Means for Solving the Problems]
For this reason, the present invention provides a sheet storing means for stacking and storing sheets, a sheet feeding means for feeding a sheet from the sheet storing means, a feeding roller for feeding a sheet fed from the sheet feeding means, and a feeding roller. A separating unit including a separating member that is in pressure contact with the roller, and driving the separating unit.Having a first motorA driving unit, a pair of registration rollers for transferring the sheet separated and fed by the separation unit to a conveyance roller disposed downstream of the sheet feeding path, and setting the pair of registration rollers to a sheet nip state or a sheet open state.With a second motorPressure contact / separation means;After the sheet is delivered to the transport roller, the second motor is driven to rotate forward to shift the registration roller pair from the sheet nip state to the sheet open state, and the rear end of the sheet moves the registration roller pair. After passing, the second motor is driven in reverse rotation to shift the registration roller pair to the sheet nip state, and the first motor is driven in normal rotation to feed the next sheet from the feeding roller. In the sheet feeding device configured to perform feeding, the first rotation driving of the first motor starts after the second motor driven in the reverse rotation reaches a constant speed.Another object of the present invention is to provide a sheet feeding device.
[0014]
by this,The sheet feeding device according to the present inventionSince the sheet feeding unit can feed the next sheet to the sheet separating unit when the separating unit is shifting from the sheet open state to the sheet nip state, high-speed sheet supply to the image forming apparatus is possible. It is.
Furthermore, in the sheet feeding apparatus according to the present invention, although the driving of the plurality of driving means is performed in parallel and in parallel, the maximum load current of the apparatus can be reduced.
[0015]
Here, one method of detecting that the trailing edge of the sheet has passed the separating means is to detect the passage of the trailing edge of the sheet by the detecting means for detecting the passing of the sheet in the sheet conveying path between the separating means and the registration roller pair. I do.
[0016]
The present invention is also an image forming apparatus main body, further comprising: a sheet feeding device for supplying a stacked and stored sheet, which is detachably provided, and a sheet aligning unit for aligning the sheet to a predetermined sheet conveyance reference side. The feeding device includes sheet storage means for stacking and storing sheets, sheet feeding means for feeding the sheet from the sheet storage means, a feeding roller for feeding the sheet fed from the sheet feeding means, and a pressure contact with the feeding roller. A separating member comprising a separating member, a driving unit for driving the separating unit, and a leading end of a sheet separated and fed by the separating unit. A pair of registration rollers to be delivered to the sheet aligning means, and a pressing / separating means for bringing the pair of registration rollers into a sheet nip state or a sheet open state. The pressure contact / separation means shifts the pair of registration rollers from the sheet nip state to the sheet open state after the sheet is delivered to the aligning means, and the rear end of the sheet moves the registration roller pair. It is an object of the present invention to provide an image forming apparatus wherein the pair of registration rollers shifts to a sheet nip state after passing.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an image forming apparatus provided with the sheet feeding device according to the present invention will be described in detail with reference to the drawings.
[0022]
FIG. 1 shows an example of sheet feeding apparatuses 1 (a) and 1 (b) stored in an image forming apparatus (copying apparatus) H and located at a sheet feeding position. FIG. 2 shows a state in which the sheets stored in the sheet feeding device 1 are separated one by one by sheet feeding means such as a feeding roller 8 and fed to the printer.
[0023]
The image forming apparatus H includes a laser scanner that scans laser light in accordance with image information, an image processing unit, a transfer roller, a fixing device (all not shown), a transport roller 9 and the like on an upper portion of the apparatus main body H. Printer is formed. A sheet feeding device 1 is formed below the main body of the device H. The sheets S stored in the sheet feeding apparatuses 1 and 2 are configured to be conveyed to the printer at a predetermined timing by conveying means including a feeding roller 8 as shown in FIG.
[0024]
FIG. 1A illustrates a configuration in which a plurality of sheet feeding apparatuses 1, 2a, and 2b are provided in an image forming apparatus H. Each of the sheet feeding devices 1, 2a, and 2b is configured to function independently. The sheet feeding device 1 is a feeding device having sheet size detecting means on which sheets of various sizes can be stacked. The sheet feeding devices 2a and 2b may be assigned and used as the sheet feeding devices 2a and 2b for the fixed size sheet S.
[0025]
FIG. 1B illustrates an image forming apparatus H including only a sheet feeding apparatus 1 having a sheet size detecting unit capable of stacking sheets of various sizes. The image forming apparatus H is smaller than the apparatus shown in FIG. 1A because the sheet is fed only by the sheet feeding apparatus 1 capable of stacking a plurality of sizes of sheets.
[0026]
Here, the configuration and operation of the sheet feeding apparatus 1 according to the embodiment will be described.
The sheet feeding apparatus 1 includes a sheet storage unit (sheet storage cassette) 19, a sheet support table 7 provided in the sheet storage unit 19, and a moving path between the sheet replenishment position and the sheet feeding position. And a frame 10 at one end of the supporting means 30 for fixing the same, and a feeding roller for separating and feeding the sheets one by one from the sheet storage means 19 at the sheet feeding position. 8, sheet feeding means such as a feeding roller 40, a separation roller 41, a registration roller pair 42, and the like.
[0027]
Further, inside the sheet storage means 19, a sheet regulating means (not shown) for regulating the width direction of the sheet and the rear end support guide 5 are provided.
[0028]
Further, the sheet feeding device 1 includes a sheet size detection unit 20 that detects the size of the sheet S stored in the sheet storage unit 19 in cooperation with the rear end support guide 5.
[0029]
FIG. 3 is a perspective view illustrating an example of the sheet feeding apparatus, and illustrates a state in which the sheet feeding apparatus 1 is pulled out from the main body frame 10 of the image forming apparatus H and is located at a sheet replenishing position.
[0030]
By holding the handle 17 provided on the front cover 18 of the sheet storage means 19 stored in the main body frame and pulling it toward the user, the sheet storage means 19 (cassette) can be moved to the sheet replenishing position. During the movement, the support rail, which is the support means 30 supporting the sheet storage means 19, is configured to be able to expand and contract. One end of the support means 30 is fixed to the frame.
[0031]
The sheet storage means 19 is guided by the support rail of the support means 30 and is pulled out to the sheet replenishing position. Then, the sheet S is stored in the sheet storage unit 19 in a state where the sheet storage unit 19 is pulled out from the frame 10. At this time, the sheet detecting means 20 and the coupling 12 of the lift-up driving means provided on the main body frame are separated from the sheet storing means 19.
[0032]
The space formed between the main body frame 10 and the sheet storage means 19 when the sheet storage means 19 is pulled out to the sheet replenishing position is a movement path of the sheet storage means 19.
[0033]
FIG. 4 is a perspective view showing a state where the present sheet feeding apparatus is located at a sheet feeding position in a main body frame of the image forming apparatus.
[0034]
To move the sheet storage means 19 to the sheet feeding position, the front cover 18 of the sheet storage means 19 at the above-described sheet replenishing position is pushed into the frame of the main body.
When the front cover 18 of the sheet storage means 19 is pushed and pushed into the frame of the main body, the support rail of the support means 30 supporting the sheet storage means 19 contracts, and the sheet storage means 19 moves to the sheet feeding position.
[0035]
The sheet size detection means 20 is provided at a position where the sheet size detection means 20 enters the movement path in the frame. Therefore, when the sheet storage means 19 is pushed in and positioned at the sheet feeding position, the sheet size detection means is disposed at a position overlapping with the sheet storage means 19 when viewed from the sheet stacking direction.
[0036]
At this time, the lever pressing portion 25 provided at one end of the sheet rear end regulating guide 5 comes into contact with one or a plurality of detection lever contact portions formed on one or a plurality of size detection levers of the sheet size detection means 20. It is configured as follows. Further, a coupling 12 as a drive transmission means for moving up and down the sheet support 7 is fitted and coupled to a coupling pin 14 provided in the sheet storage means 19.
[0037]
FIG. 5 is a block diagram illustrating a configuration of a control mechanism of the image forming apparatus H and the sheet feeding apparatus 1 according to the present invention. The configuration for controlling sheet feeding includes a CPU 100 for storing programs and data and controlling each device, and detecting the sheet feeding data connected to the CPU 100 and transmitting the detected data to the CPU. Sheet empty detection sensor 101, sheet level detection sensor 102, door open / close detection sensor 103, conveyance sheet detection sensor A (registration sensor 51), conveyance sheet detection sensor B (separation sensor 52), sheet near empty detection sensor 104, sheet size detection The sensor 21 includes a sensor 21, a separation roller home position sensor 47, and a registration roller home position sensor 72. Further, the CPU 100 includes a separation motor M1 for providing drive for separation / pressure contact of the separation roller and driving for sheet conveyance by the separation roller, and a drive for separation / pressure contact of the registration roller, and sheet conveyance for the registration roller. A registration motor M2 for driving and a lift-up motor 11 for lifting and lowering a hopper on which sheets are loaded are connected.
[0038]
FIG. 6 is a cross-sectional view illustrating a state in which the sheet feeding device 1 is attached to the lower stage of the image forming apparatus main body H, and illustrates a sheet feeding state (No. 1), and FIG. 3 illustrates a state in which the sheet S stacked on the sheet storage unit 19 of the sheet feeding device 1 is fed by the feeding roller 8 and fed to the feeding roller 40 and the separation roller 41 pair. The sheets S stacked in the sheet storage means 19 are lifted up and stopped at the sheet feeding position. When a paper feed signal is received from the main body, paper feeding is started.
[0039]
The sheet S stacked on the sheet storage means 19 is raised from the standby position and is fed to the feed roller 40 and the separation roller 41 pair by the feed roller 8 in a state of being in contact with the feed roller 8.
At this time, the feed roller 40 and the separation roller 41 are in a nip state. The separation roller 41 has a function of separating the fed sheets one by one.
[0040]
FIG. 6B shows a state in which the sheet fed by the pair of the feeding roller 40 and the separation roller 41 abuts on the registration roller 42 and is aligned. The sheets S separated one by one pass through the separation sensor 52 and the registration sensor 51, temporarily stop and align before the registration roller 42, and then are fed to the conveyance roller 9 on the image forming apparatus main body side. . At this time, the feed roller 40 and the separation roller 41 are in pressure contact (hereinafter, appropriately referred to as nip).
[0041]
FIG. 7 shows a sheet feeding state (part 2) following FIG. 3A illustrates a state in which the sheet is nipped by the registration roller 42 and fed to the main device. The sheet aligned before the registration roller 42 is nipped by the registration roller 42 and travels a predetermined distance, so that the feeding roller 40 and the separation roller 42 are separated. This separation is because the aligned sheet does not bend. (B) shows a state in which the sheet fed from the registration roller 42 is nipped by the pair of the conveying roller 9 and the aligning roller 9b on the main body side and conveyed by the aligning roller 9b while being biased to the sheet feeding reference. . In this state, the pair of registration rollers 42 is separated. The pair of the feed roller 40 and the separation roller 41 are also separated. Since the rollers are separated in this manner, the sheet fed while being biased is fed along the sheet feeding standard without bending.
[0042]
FIG. 8 shows a sheet feeding state (part 3) following FIG. 9A illustrates a state where the rear end of the fed sheet has passed the separation sensor 52. FIG. When the rear end of the sheet passes the separation sensor 52, the pair of the feeding roller 40 and the separation roller 41 is pressed against each other in preparation for feeding the next sheet. The fed sheet S is passing through the pair of registration rollers 42, and the pair of registration rollers 42 is separated. 7B illustrates a state in which the rear end of the fed sheet has passed through the registration sensor 51 and has been fed a predetermined distance. When the trailing edge of the fed sheet passes through the registration sensor 51 and is fed by a predetermined distance, and passes through the registration roller 42, the registration rollers 42 are pressed against each other. Here, the feeding roller 40, the separation roller 41 pair, and the registration roller 42 pair are ready to receive the next sheet feeding.
[0043]
Here, the configuration of the pressure contact / separation drive mechanism of the feed roller 40 and the separation roller 41, which is the first drive means having the first pressure contact / separation means in the embodiment of the present invention, will be described.
[0044]
FIG. 9 is a perspective view showing a configuration of a pressure contact / separation drive mechanism of the feed roller 40 and the separation roller 41 as the first drive means. The sheet feeding means includes a feeding roller 8 for feeding the uppermost sheet S of the sheets stacked in the sheet storage means 19, and a feeding roller 8 for feeding the sheet S fed from the feeding roller 8 to the registration roller pair 42. A feed roller 40, a separation roller 41 for separating sheets one by one with the feed roller 40, a separation roller support member 44, and an eccentric cam 43 for separating the separation roller 41 from the feed roller 40; And one-way clutches 45a and 45b for transmitting rotational driving to the feeding roller 8, the feeding roller 40 and the separating roller 41, and belts 46a and 46b for transmitting the driving force of the motor M1 to the gears.
[0045]
FIG. 9A shows a state in which the sheet stacked in the sheet storage unit 19 is fed by the feeding roller 8 to the feeding roller 40, and the feeding roller 40 and the separation roller 42 are joined to separate the sheets one by one. This shows a state in which the sheet is being fed. At this time, the eccentric cam 43 is separated from the separation roller support member 44, and the sensor 47 is in the ON state.
[0046]
In FIG. 9B, when the sheet is fed from the feed roller 40 toward the registration roller by a predetermined distance, the rotated eccentric cam 43 pushes the separation roller support member 44 and the feed roller 40 and the separation roller 42 is separated. As a result, the driving load of the registration roller is reduced. Further, by separating the feed roller 40 and the separation roller 42, the second sheet is not fed until the first sheet completely leaves the feed roller 40. At this time, the sensor 47 is turned off.
[0047]
FIG. 10 shows a configuration of a pressure contact / separation drive mechanism between the feeding roller 40 and the separation roller 41. The sheet S aligned before the registration roller 42 is nipped by the registration roller 42 and travels a predetermined distance, whereby the feeding roller 40 and the separation roller 41 are separated.
[0048]
Here, an operation of moving the separation roller 41 and the feeding roller 40 from a separated state to a nipped state will be described.
[0049]
When the trailing edge of the fed sheet passes the separation sensor 52, the motor M1 for driving the separation roller 41 starts reverse rotation. The reverse rotation drive of the motor M1 is transmitted to the eccentric cam 43 via the belt 46a and the one-way clutch 45b. The eccentric cam 43 rotates to release the pushing force pushing the separation roller support member 44 in the direction of arrow X.
[0050]
Since the separation roller 41 is urged by a spring or the like (not shown), the separation roller 41 is pulled back and pressed against the feed roller 40. When the separation roller 41 and the feed roller 40 are pressed against each other, the sensor 47 is turned on. The motor M1 stops. The feeding roller 40 and the separation roller 41 are now ready to receive the next sheet. Then, it waits for the next sheet to be fed.
[0051]
Next, a description will be given of a pressure contact / separation driving mechanism of the registration roller 42, which is a second driving means having the second pressure contact / separation means.
[0052]
FIG. 11 is a perspective view of a registration roller driving mechanism. (A) shows a state where the registration roller pair 42 is nipped, and (b) shows a state where the registration roller pair 42 is opened. The second driving unit includes a registration motor M2 that can rotate forward and reverse to drive the registration roller 42 and the pressure contact / separation unit, a belt 66 that transmits the driving of the registration motor M2 to the registration roller 42, a sheet that is aligned and fed to the main body. Pair of registration rollers 42a and 42b, an eccentric cam 43b for pressing and separating the registration roller 42, a guide plate 65 for guiding the sheet and supporting the eccentric cam, and a spring for urging the registration roller 42b in the pressing direction. 70, a sensor 72 for detecting the pressure roller release of the registration roller, and a cam lug 71.
[0053]
FIG. 12 shows a pressure contact / separation drive mechanism of the registration roller 42. FIG. 4A is a side view of a pressure contact / separation drive mechanism of the registration roller 42. (B) shows a plan view of (a). The sheet fed from the registration roller 42 is nipped by a pair of the conveying roller 9 and the aligning roller 9b on the main body side, and is conveyed by the aligning roller 9b while being shifted to a sheet feeding reference. A registration sensor 51 detects the rear end of the sheet fed by the aligning roller on the main body side.
[0054]
In this state, the CPU calculates and sets a timer value based on the sheet feeding speed and the distance from the registration sensor 51 to the registration roller pair 42. When the timer recognizes that the time of the set timer value has elapsed (the sheet has been fed a predetermined distance and has passed between the pair of registration rollers), the registration motor M2 starts reverse rotation. The registration roller 42a does not rotate backward because it is connected by the one-way clutch 60.
[0055]
The reverse rotation drive of the motor M2 is transmitted to the eccentric cam 43b via the belt 66 and the one-way clutch 61. The eccentric cam, which has pressed the guide plate to separate the registration rollers 42a and 42b, rotates to release the pressing force for pressing the guide plate 65.
[0056]
The registration roller 42b is pressed against the registration roller 42a by an urging force urged toward the registration roller 42a by a spring 70 or the like. At this time, the sensor 72 is turned on, and transmits a signal indicating that the registration roller 42 has been pressed to the CPU 100 of the main body. After being pressed, the registration motor M2 stops.
[0057]
As a result, the feeding roller 40 and the separation roller 41, which are the first driving unit, and the registration roller pair 42, which is the second driving unit, are nipped, and are in a standby state for receiving the next sheet feeding. .
[0058]
Further, in the present invention, the control is performed such that the drive start timings of the first drive unit and the second drive unit do not coincide. Driving of the first driving means and the second driving means is performed by a separation motor M1 and a registration motor M2, respectively. For starting and stopping the driving of the motor, the sensor detects the position of the sheet that is rapidly fed, and sends a signal to the CPU 100 (control device) to control the starting and stopping of the motor.
[0059]
FIG. 13 is a diagram showing the relationship between the driving speed of the registration motor and the separation motor, and the start and stop. FIG. 14 is a diagram showing the relationship between the current consumption of the registration motor and the separation motor and the start and stop. When the motor starts and stops, the power consumption increases and when the rotation reaches a predetermined stable rotation speed, the power consumption also stabilizes. The current consumption also increases when the motor stops.
[0060]
After the sheet has passed through the registration rollers 42, the registration motor M2 is started to rotate in the reverse direction to start the operation of pressing the registration rollers. On the other hand, the separation roller activates the separation motor M1 to rotate forward to feed the next sheet and starts driving the separation roller. At this time, if the registration motor M2 and the separation motor M1 are started at the same time, the power consumption increases extremely, which may affect other components.
[0061]
In the present invention, the start of the registration motor M2 and the start of the separation motor M1 are shifted so that the start of the start does not overlap with the start of the registration motor M2.
[0062]
Here, the operation of pressing and separating the registration roller and the separation roller will be described with reference to a flowchart.
FIG. 15 is a flowchart showing a flow in which the sheet is fed by the pair of registration rollers 42. Waiting for the separation motor M1 to stop, and when the separation motor M1 stops (S18), waits for a predetermined time (for example, 600 ms) to shift the sheet feeding timing (S19). After a lapse of a predetermined time (600 ms), the registration motor M2 is started to start feeding the sheet to the main body (forward rotation) (S20). When the leading edge of the sheet has passed 10 mm from the registration roller 42, the separation motor M1 that drives the separation roller 41 starts reverse rotation start, and the separation roller starts separation (S21, S22).
[0063]
FIG. 16 is a flowchart showing a flow in which the sheet S is conveyed by the registration rollers 42 following FIG. The aligning roller 9b on the main body side waits for the leading edge of the sheet from the registration roller 42 (S23), and when the leading edge of the sheet reaches, the registration motor M2 stops (S24). Here, the registration motor M2 starts reverse rotation start, and the registration roller 42 starts separation (S25). When the trailing edge of the sheet passes through the separation sensor 52, the separation sensor 52 is turned off (S26), and the separation motor M1 starts reverse rotation start. The separation roller 41 that has been separated by the reverse rotation of the separation motor M1 starts the nip operation (S27). When the separation roller 41 is nipped, the next sheet can be fed (S28, S29).
[0064]
FIG. 17 is a flowchart showing a flow in which the registration roller 42 is nipped subsequent to FIG. When the trailing edge of the sheet passes through the registration sensor 51 (S31), a waiting timer for starting the nip of the separated registration rollers 42 is set (S32). When the time count is started and the time is up (S33), the nip operation of the registration roller 42 is started (S34). The separation motor M1 is restarted (forward rotation) to wait for the next sheet (S35). Wait for the pair of registration rollers 42 to be nipped (S36), and when the nip operation is completed, the registration motor M2 stops (S37).
[0065]
As described above in detail, in the sheet feeding apparatus according to the present invention, the sheet storage unit for stacking and storing sheets, the sheet feeding unit for feeding the sheet from the sheet storage unit, and the sheet fed from the sheet feeding unit. , Which is composed of a feed roller for feeding paper, and a separating member pressed against the feed roller, and arranges the leading end of the sheet separated and fed by the separating means and arranges the sheet on the downstream side of the sheet feeding path. A pair of registration rollers to be transferred to the conveyed rollers, a first driving unit for driving the separation unit, the first pressure contact / separation unit for setting the separation unit to a sheet nip state or a sheet open state, A second driving unit for driving the registration roller pair, the second pressure contact / separation unit for setting the registration roller pair to a sheet nip state or a sheet open state; And the first pressure contact / separation means shifts the separation means from the sheet nip state to the sheet open state after the sheet is delivered to the pair of registration rollers, and the rear end of the sheet is separated After passing through the means, the separating means is shifted to a sheet nip state.
[0066]
Accordingly, the present invention is advantageous in that the sheet feeding means can feed the next sheet to the sheet separating means when the separating means is shifting from the sheet open state to the sheet nip state. The speed of sheet supply was realized.
[0067]
Also, in the present invention, a driving operation for sheet feeding by the first driving unit, and a state transition operation between a sheet open state and a sheet nip state in the registration roller pair by the second pressure contact / separation unit. Although the driving is performed in parallel for a predetermined period of time, the driving start of the first driving unit and the driving start of the second driving unit are controlled so that the respective driving start timings do not coincide with each other. Starts the activation of the other motor after one of the first motor constituting the first driving means or the second motor constituting the second driving means has reached a constant speed. As a result, the maximum load current of the apparatus is reduced, and efficient sheet feeding is realized.
[Brief description of the drawings]
FIG. 1 shows a sheet feeding apparatus housed in an image forming apparatus such as a copying apparatus and located at a sheet feeding position.
FIG. 2 is a sectional view of a sheet feeding unit of the sheet feeding apparatus.
FIG. 3 is a perspective view showing a state in which the feeding device is pulled out from the main body frame of the image forming apparatus and is located at a sheet replenishing position.
FIG. 4 is a perspective view illustrating a state in which the sheet feeding device is located at a sheet feeding position in a main body frame of the image forming apparatus.
FIG. 5 is a block diagram illustrating a configuration of a control mechanism of the image forming apparatus and the sheet feeding apparatus.
FIG. 6 is a cross-sectional view of the image forming apparatus main body and the sheet feeding device, showing a sheet feeding state (part 1).
FIG. 7 shows a sheet feeding state (part 2) following FIG. 6;
FIG. 8 shows a sheet feeding state (No. 3) following FIG. 7;
FIG. 9 is a perspective view of a driving mechanism of the sheet feeding device.
FIG. 10 is a configuration diagram of a pressure contact / separation mechanism of a separation roller.
FIG. 11 is a perspective view of a driving mechanism of a registration roller.
FIG. 12 is a configuration diagram illustrating a pressure contact / separation mechanism of the registration roller.
FIG. 13 is a diagram showing a relationship between driving speeds of a registration motor and a separation motor, and starting and stopping.
FIG. 14 is a diagram showing a relationship between current consumption of a registration motor and a separation motor, and starting and stopping.
FIG. 15 is a flowchart (part 1) illustrating an operation between sheet feeding and pressure contact / separation of a separation roller.
FIG. 16 is a flowchart (part 2) for explaining the operation between sheet feeding and pressure contact / separation of the separation roller, continued from FIG. 15;
FIG. 17 is a continuation of FIG. 16, showing a flowchart (part 3) for explaining an operation between sheet feeding and pressure contact / separation of the separation roller.
[Explanation of symbols]
1 Sheet feeding device
7 Seat support
8 Feeding roller
10 frames
11 Lift-up motor
19 Seat storage means
20 Size detection sensor
22 Size detection lever
40 feed roller
41 Separation roller
42 registration roller pair
43 Eccentric cam
44 Separation roller support member
45a, 45b one-way clutch
46a, 46b belt
51 Registration sensor
52 Separation sensor
65 Guide plate
67 Transport reference plate
68 Main unit transport reference plate
M1 separation motor
M2 registration motor
H Image forming device

Claims (5)

Sheet storage means for loading and storing sheets,
Sheet feeding means for feeding a sheet from the sheet storage means,
A separating unit configured to include a feeding roller that feeds the sheet fed from the sheet feeding unit and a separating member that presses against the feeding roller;
Driving means having a first motor for driving the separating means;
A pair of registration rollers for transferring the sheet separated and fed by the separation unit to a conveyance roller disposed downstream of the sheet feeding path,
Pressure contact / separation means having a second motor for bringing the pair of registration rollers into a sheet nip state or a sheet open state,
After the sheet is delivered to the transport roller, the registration roller pair is shifted from the sheet nip state to the sheet open state by driving the second motor to rotate forward,
After the trailing edge of the sheet passes through the pair of registration rollers, the second motor is driven in reverse rotation to shift the pair of registration rollers to a sheet nip state, and the first motor is driven forward. In a sheet feeding apparatus configured to feed a next sheet from the feeding roller,
The sheet feeding apparatus according to claim 1, wherein the forward rotation driving of the first motor is started after the second motor driven in the reverse rotation reaches a constant speed . 2. The sheet feeding device according to claim 1, wherein the forward rotation driving of the first motor is performed for a predetermined time overlap with the reverse rotation driving of the second motor. 3. An image forming apparatus main body including a sheet feeding device that supplies stacked and stored sheets detachably, and a sheet aligning unit that aligns the sheet with a predetermined sheet conveyance reference side,
The sheet feeding device,
Sheet storage means for loading and storing sheets,
Sheet feeding means for feeding a sheet from the sheet storage means,
A separating unit configured to include a feeding roller that feeds the sheet fed from the sheet feeding unit and a separating member that presses against the feeding roller;
Driving means for driving the separating means;
A pair of registration rollers for adjusting the leading end of the sheet separated and fed by the separating unit, and transferring the sheet to the sheet aligning unit of the image forming apparatus disposed downstream.
Pressure contact and separation means for bringing the pair of registration rollers into a sheet nip state or a sheet open state,
The pressure contact / separation unit shifts the pair of registration rollers from a sheet nip state to a sheet open state after the sheet is delivered to the aligning unit, and the registration roller pair after the rear end of the sheet passes through the registration roller pair. An image forming apparatus, wherein a pair shifts to a sheet nip state. Detecting means for detecting passage of a sheet in a sheet conveyance path between the pair of registration rollers and the sheet aligning is installed, and after the detecting means detects passage of a trailing end of the sheet, the pressing / separating means immediately moves the pair of registration rollers to the sheet. The image forming apparatus according to claim 3 , wherein the image forming apparatus is in a nip state. A driving operation for feeding the sheet by the driving unit and a state transition operation between the sheet open state and the sheet nip state in the registration roller pair by the pressing / separating unit are performed in parallel for a predetermined time. the image forming apparatus according to claim 3 or 4, wherein.

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