JP4454869B2 - Sheet feeding device - Google Patents

Description

[0001]
[Industrial application fields]
In the present invention, a sheet feeding device (hereinafter referred to as a sheet feeding device) for separating the stacked recording sheets (cut sheets) one by one and feeding them to a processing unit such as a recording unit is simply referred to as “feeding”. Device)).
[0002]
[Prior art]
Recording devices such as printers, copiers, and facsimiles record images on recording sheets (recording materials) such as paper and plastic thin plates by driving the energy generator of the recording head according to the recording information. It is configured to go.
[0003]
The recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a recording method.
[0004]
In addition to plain paper, recording sheets used in the recording apparatus include thick paper such as postcards and envelopes, and special sheets such as plastic thin plates.
[0005]
The recording sheet is manually fed or automatically fed by an automatic feeding device.
[0006]
The automatic feeding device generally includes a feeding drive unit that feeds a recording sheet by rotating a feeding roller and a feeding cassette unit that is loaded with a recording sheet, and drives a conveyance system of the recording apparatus. By using the force to drive the feeding roller, the recording sheets are separated and fed one by one.
[0007]
In addition to the built-in type incorporated in the recording apparatus, the automatic feeding apparatus includes an external type that is detachably mounted.
[0008]
As the automatic feeding device as described above, the feeding roller, the pressure plate, and the separation claw that can be engaged with both sides of the front end of the recording sheet, the recording sheet on the pressure plate is fed to the feeding plate. A configuration is known in which a roller and the separation claw cooperate to separate each sheet and supply it to a processing unit such as a recording unit.
[0009]
As the separation claw, there are known a movable separation claw that moves together with the pressure plate and a fixed separation claw that is fixed to the apparatus main body.
[0010]
As the automatic feeding apparatus as described above, those shown in FIGS. 14 and 15 have been proposed. FIG. 14 is a front view of the automatic feeding device, and FIG. 15 is a side view.
[0011]
The feeding device includes a feeding roller 35, a separation claw 36, a movable side guide 32, a base 31, a pressure plate 30, a pressure plate spring 34, driving gears 22 to 28, a release cam 29, a claw spring 26, and the like. Usually, since the release cam 29 pushes down the pressure plate 30, the recording sheet P is separated from the feeding roller 35.
[0012]
In a state where the recording sheet P is set, the driving force is transmitted to the feeding roller 35 and the release cam 29 by the gears 22 to 28. When the release cam 29 is separated from the pressure plate 30, the pressure plate 30 is raised, the feeding roller 35 and the recording sheet P come into contact with each other, picked up as the feeding roller 35 rotates, and separated one by one by the separation claw 36. The separated recording sheet P is sent to the recording unit. The feeding roller 35 and the release cam 29 make one rotation until the recording sheet P is fed to the recording unit, and the driving force is cut again while the pressure plate 30 is released from the feeding roller 35, and this initial state is maintained. .
[0013]
[Problems to be solved by the invention]
However, in the conventional feeding apparatus as described above, the feeding roller 35 and the release cam 29 of the pressure plate 30 rotate in synchronization via other power transmission means, in the above-described case, the gears 22 to 28. Was. Therefore, when the recording sheet P stacked on the pressure plate 30 comes into contact with the feeding roller 35, the feeding roller 35 has already started rotating. In this case, the recording sheet P comes into contact with the already rotating feeding roller 35, and the contact load of the sheet to the left and right feeding rollers is insignificant during the vibration damping period when the pressure plate is in contact. Since it becomes stable, the behavior of the sheet becomes unstable, and skew is particularly likely to occur.
[0014]
In order to solve this problem, in the invention described in Japanese Patent Application Laid-Open No. 09-077273, after the release means that pushes down the pressure plate is released, the recording sheets loaded on the pressure plate are fed by releasing the release means. By temporarily stopping the driving until the roller comes into contact with the roller, the state at the contact portion between the feeding roller and the recording sheet is stabilized, and skew of the fed sheet is prevented.
[0015]
However, in the invention described in Japanese Patent Application Laid-Open No. 09-077273, the feeding roller that rotates in synchronization with the release cam temporarily stops the drive source, for example, the stepping motor, when the pressure plate is released by the release cam. In order to stop temporarily, the timing to stop the feeding roller depends on the control unit. For example, when a stepping motor is used as the drive source, the position of the release cam is grasped by counting the number of steps (number of drive pulses) of the stepping motor by the control unit. In this case, the feeding roller rotates until the release cam releases the pressure plate, and the time from when the pressure plate is released until the recording sheet comes into contact with the feeding roller is extremely short (for example, the above-described special feature). In the case where no pressure reducing means is provided on the pressure plate portion as described in Kaihei 09-077773), the recording sheet comes into contact with the feeding roller while the feeding roller stops or not. Can happen.
[0016]
[Means for Solving the Problems]
The configuration of the present invention for solving the above problems includes a sheet stacking unit capable of stacking a plurality of recording sheets, a feeding roller for feeding the recording sheet, and a recording sheet stacked on the sheet stacking unit. A spring for urging the sheet stacking means in the direction of the feed roller in order to contact the feed roller; and a gear portion that rotates by receiving a drive from a drive source and has a toothless portion; A release cam that retreats the sheet stacking unit with respect to the feeding roller against the urging force, and a synchronous rotation with the feeding roller, and meshing with the gear portion of the release cam, thereby bringing the feeding path roller into the feeding path roller. And a gear that transmits drive from a drive source, and the recording sheet stacked on the sheet stacking means is brought into contact with the feeding roller by the rotating release cam. The driving force is not transmitted to the feeding roller with the portion facing the gear, and after the recording sheet contacts the feeding roller, the gear portion of the release cam meshes with the gear, and the feeding roller The sheet feeding device is characterized in that a driving force is transmitted to the sheet feeding device.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to specific examples together with the drawings.
[0029]
[Example 1]
1 and 2 show an embodiment of the present invention. FIG. 1 is a side view of the feeding device, and FIG. 2 is a cross-sectional view. The feeding device includes a feeding roller 6, a separation claw 8, a movable side guide 12, a base 11, a pressure plate 7 as a sheet stacking unit, a pressure plate spring 10 as a sheet contact unit, driving gears 1 to 3, a release It comprises a release cam 4 and a claw spring 9 as means. Since the release cam 4 pushes down the pressure plate 7 during standby, the recording sheet P is separated from the feeding roller 6. The feeding roller 6 is a half-moon roller for reducing back tension, and a roller (not shown) is attached on the shaft.
[0030]
FIG. 3 shows the operation flow of the feeding apparatus, and the operation will be described along this flow. First, power is transmitted from a motor (not shown) to the input gear 1 via a driving force transmission system such as a gear (a driving transmission system from the motor to the input gear 1 is not shown). The release cam 4 rotates in synchronization with the input gear 1 from the input gear 1 via the gears 2 and 3. The release cam 4 has a gear portion for transmitting power from the gear 3. As shown in FIG. 4, the release cam 4 is an intermittent gear having a missing tooth portion. The drive source of the gear 5 is the same motor as the drive source of the feeding roller 6. Since the gear 5 that rotates in synchronization with the feed roller 6 can transmit power from the gear portion of the release cam 4 that is an intermittent gear, even if the release cam 4 rotates continuously, the tooth missing of the release cam 4 It becomes discontinuous operation in the part. That is, there is an area where the gear 5 is not rotating even when the release cam 4 is rotating. That is, the release cam 4 also functions as a driving force intermittent transmission means for the feeding roller.
[0031]
FIG. 5 shows a state in which the pressure plate 7 is pushed down by the release cam 4 and the feeding roller 6 is separated from the recording sheet P. This time is defined as an initial position. At this time, as shown in FIG. 5, the release cam 4 and the gear 5 are in a state where their teeth are engaged with each other. From this initial state, the release cam 4 starts rotating upon receiving power, and at the same time, the gear 5 and the feeding roller 6 also start rotating.
[0032]
Thereafter, a missing tooth portion provided in a gear portion of the release cam 4 appears at a contact position between the release cam 4 and the gear 5. When the leading edge of the missing tooth portion of the release cam 4 appears at the contact position with the gear 5, the pressure plate 7 is still pushed down by the release cam 4.
[0033]
When the release cam 4 continues to rotate, the pressure plate 7 is released. At the time when the pressure plate 7 is released, the toothless portion of the release cam 4 is in contact with the gear 5, so that the gear 5 cannot receive the driving force and stops rotating, and at the same time, the feeding roller 6 has also stopped rotating. When the pressure plate 7 is released, the recording sheet P stacked on the pressure plate 7 is pushed up by the pressure plate spring 10 and comes into contact with the stopped feeding roller.
[0034]
It should be noted that when the tooth portion of the gear portion of the release cam 4 is in the contact position with the gear 5, a phase shift of the feeding roller 6 is prevented by a friction material (not shown).
[0035]
FIG. 6 shows a state after the pressure plate 7 is released without rotating the gear 5, that is, the feeding roller 6, by using the toothless portion of the release cam 4. Thereafter, the missing tooth portion of the release cam 4 passes, the tooth portions of the release cam 4 and the gear 5 are engaged again, and the sheet feeding roller starts to rotate. Subsequently, by operating the release cam 4, the feeding roller 6 is rotated, the recording sheets P are picked up, separated one by one by the separation claw 8, and the recording sheets P are separated and fed to the printer body. When the release cam makes one rotation and the uppermost sheet is fed, the pressure plate 7 is pushed back by the release cam 4 and moves backward, and then returns to the initial position again.
[0036]
When the recording sheet P abuts on the feeding roller 6, the abutting portion of the feeding roller may be either an arc portion of the feeding roller 6 or a D-cut portion (roller 13) (FIGS. 7 and 7). 8).
[0037]
In this way, when the rotation of the feeding roller is stopped, the recording sheet can be brought into contact with the feeding roller, and then the feeding roller can be rotated to feed the recording sheet.
[0038]
[Example 2]
Next, Example 2 will be described. In the first embodiment described above, after the gear 5 and the feeding roller 6 that have once moved together with the release cam 4 are stopped before the pressure plate 7 is released, the recording sheet P is in contact with the stopped feeding roller 6. It started again. In the second embodiment, when the missing tooth portion provided in the gear portion of the release cam 4 is in the contact position with the gear 5, a rotation locking mechanism for the feeding roller 6 is separately provided, so that the release cam 4 Thus, only the release cam 4 is driven and starts rotating while the feeding roller 6 is stopped when the recording sheet P is pressed by the pressure plate 7. FIG. 9 shows an operation flow of the second embodiment.
[0039]
FIG. 10 shows a state where the pressure plate 7 is pushed down by the release cam 4 and the feeding roller 6 is separated from the recording sheet P. At this time, unlike Example 1 (FIG. 5), the toothless portion of the gear portion of the release cam 4 is in contact with the gear 5, and this time is defined as the initial position. By using the toothless portion provided in the gear portion of the release cam 4 when moving from here, as shown in FIG. 10, only the release cam 4 is operated to release the pressure plate 7, and the feeding roller 6 is used for recording. Even if the sheet P is brought into contact, the feeding roller 6 has not yet rotated at this point.
[0040]
Here, in the initial state, the toothless portion of the gear portion of the release cam 4 is in the contact position with the gear 5, so that the gear 5 can freely rotate within a certain range. That is, since the feeding roller 6 can also rotate freely, a means for preventing phase shift is necessary.
[0041]
11 and 12 are explanatory diagrams of the phase shift prevention stopper. FIG. 11 shows a state in which the recording sheet of the feeding device is not in contact with the feeding roller, and FIG. 12 shows that the pressure plate 7 is released and the recording sheet P comes into contact with the feeding roller 6 so that the feeding operation is performed. That is when it is done. A disk or a cylinder 6a having a notch in a part so as not to obstruct the feeding on the axis of the feeding roller 6 is provided. This may be integrated with the feed roller 6 or may be provided with a separate member. On the other hand, a stopper 7a extends from the pressure plate 7, and when the pressure plate 7 is pushed down by the release cam 4, a part of the stopper 7a is part of a disk on the axis of the feeding roller 6, as shown in FIG. Alternatively, the feeding roller 6 is prevented from rotating by entering the notched portion of the column 6a. When the pressure plate 7 is released by the release cam 4 at the time of feeding, the stopper 7a is detached from the notch portion of 6a as shown in FIG. 12, and the feeding roller 6 can be rotated by receiving a driving force. Further, it is a short time from when the stopper 7a is removed until the recording sheet P comes into contact with the feeding roller 6. However, the stopper 7a is removed, and the missing tooth portion of the release cam 4 is in contact with the gear 5. Even when the feed roller 6 is positioned at a position, the phase shift of the feeding roller 6 is prevented by a friction material (not shown).
[0042]
After the recording sheet P is brought into contact with the stopped feeding roller 6, the release cam 4 is continuously operated to rotate the feeding roller 6 and pick up the recording sheet P. Each sheet is separated, and the recording sheet P is separated and fed to the printer body. Here, when the recording sheet P abuts on the feeding roller 6, the contact portion of the feeding roller 6 is either an arc portion of the feeding roller 6 or a D-cut portion (roller) as in the first embodiment. However, they may be used (FIGS. 7 and 8).
[0043]
Accordingly, the recording sheet can be brought into contact with the feeding roller before the feeding roller rotates, and thereafter, the recording sheet can be fed by rotating the feeding roller. In addition to the friction material, as in the second embodiment, in addition to the friction material, an anti-rotation lock mechanism is further provided, so that the recording sheet is more reliably brought into contact with the stationary feeding roller. In addition, phase shift can be prevented.
[0044]
[Reference example]
Next, reference implementation is shown. In the first and second embodiments, the gear 5 that moves in synchronism with the release cam 4 and the feed roller 6 is directly meshed, and the drive is transmitted from the release cam 4 to the gear 5. FIG. 13 shows a side view of the feeding device of the reference example.
[0045]
The feeding device shown in the reference example includes a feeding roller 42, a separation claw 44, a base 48, a pressure plate 43, a pressure plate spring 45, drive gears 41, 46, 47, a release cam 40, a claw spring 44, and the like. The driving gear 41 that receives the driving force for rotating the feeding roller and the release cam 40 can obtain the driving force from independent driving gears 46 and 47, respectively. A drive switching device is provided in a driving force transmission system from a motor as a driving source, and the drive gears 46 and 47 can be controlled independently of each other via this drive switching device. The release cam 40 is driven by driving only the drive gear 47 while the gear 41, that is, the feeding roller 42 is fixed, and the pressure plate 43 is released. Then, after the recording sheet P is brought into contact with the feeding roller 42, the drive is transmitted to the driving gear 46, the feeding roller 42 is rotated to pick up the paper, and the sheet is separated one by one by the separation claw 44, and the recording is performed. Sheet P is separated and fed to the printer body.
[0046]
By providing the driving force transmission system as in the reference example, the driving of the feeding roller and the driving of the release means can be performed separately, and the recording sheet is applied to the feeding roller before the feeding roller rotates. After that, the recording sheet can be fed by rotating the feeding roller.
[0047]
【The invention's effect】
According to the present invention, in the sheet feeding device that feeds the recording sheet stacked on the sheet stacking means by the feeding roller, the recording sheet is brought into contact with the feeding roller in a state where the driving force is not transmitted, and then the feeding is performed. By rotating the feed roller and feeding the recording sheet, the behavior of the fed recording sheet is stabilized, and particularly the skew during feeding is suppressed, and the recording sheet surface, the feeding roller, Thus, there is provided a feeding device in which no slip occurs between the rollers and the roller marks can be prevented.
[Brief description of the drawings]
FIG. 1 is a side view of Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view of Embodiment 1 of the present invention.
FIG. 3 is an operation flow of Embodiment 1 of the present invention.
FIG. 4 is an enlarged view of a missing tooth portion of Embodiment 1 of the present invention.
FIG. 5 is an explanatory diagram of a release cam operation according to the first embodiment of the present invention.
FIG. 6 is an explanatory diagram of a release cam operation according to the first embodiment of the present invention.
FIG. 7 is a contact state diagram of a feeding roller and a recording sheet according to Embodiment 1 of the present invention.
FIG. 8 is a contact state diagram of a feeding roller and a recording sheet according to Embodiment 1 of the present invention.
FIG. 9 is an operational flow of embodiment 2 of the present invention.
FIG. 10 is an explanatory diagram of a release cam operation according to the second embodiment of the present invention.
FIG. 11 is an explanatory diagram 1 of feeding roller phase shift prevention means according to the second embodiment of the present invention.
FIG. 12 is an explanatory diagram 2 of feeding roller phase shift prevention means according to the second embodiment of the present invention.
FIG. 13 is a side view of a reference example.
FIG. 14 is a front view of a conventional feeding device.
FIG. 15 is a side view of a conventional feeding apparatus.
1, 2, 3, 5, 22, 23, 24, 25, 27, 28, 41, 46, 47 Drive transmission gear 4, 40 Release cam (having a missing tooth portion)
29 Release cam (no missing teeth)
6, 35, 42 Feed roller 7, 30, 43 Pressure plate 8, 36, 44 Separation claw 9, 26, 45 Claw spring 10, 34 Pressure plate spring 11, 31, 48 ASF base 12, 32 Movable side guide 13 Feed roller

Claims (4)

Sheet stacking means capable of stacking a plurality of recording sheets;
A feeding roller for feeding out a recording sheet;
A spring for urging the sheet stacking unit in the direction of the feed roller in order to bring the recording sheet stacked on the sheet stacking unit into contact with the feed roller;
A release cam that rotates in response to a drive from a drive source, has a gear portion having a toothless portion, and reverses the sheet stacking means against a feeding roller against an urging force of the spring ;
A gear that rotates synchronously with the feed roller and transmits the drive from the drive source to the feed roller by meshing with the gear portion of the release cam;
When the recording sheet stacked on the sheet stacking unit is brought into contact with the feeding roller by the rotating release cam, the missing tooth portion faces the gear and the driving force is transmitted to the feeding roller. The sheet feeding device is characterized in that, after the recording sheet comes into contact with the feeding roller, the gear portion of the release cam meshes with the gear and the driving force is transmitted to the feeding roller. 2. The sheet feeding apparatus according to claim 1, wherein when the recording sheets stacked on the sheet stacking unit by the release cam are brought into contact with the feeding roller, the feeding roller is in a stationary state. At the start of rotation of the release cam, no drive is transmitted to the feeding roller, and the recording roller loaded on the sheet stacking means by the release cam is driven to the feeding roller after contacting the feeding roller. The sheet feeding device according to claim 1, wherein the sheet feeding device is transmitted. The sheet feeding device according to claim 3, further comprising a stopper that stops the rotation of the feeding roller when a tooth missing portion of the gear portion faces the gear.

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