JPH08301474A - Sheet feeder and recorder - Google Patents

Abstract

PURPOSE: To surely prevent the generation of double feed by separating one by one a large number of loaded sheets. CONSTITUTION: A sheet P is placed in a condition that it is conveyed to the downstream, to hold a separating pawl 3, rotation supported to a support point 3a, in a condition that the pawl is prevented from coming into press contact relating to the sheet P on a base 5. (a) When control of reversely conveying the sheet to the upstream is performed, a sheet on the base 5 into contact with the sheet P during conveyance and further adjacent several number of sheets are pressed up to the upstream by frictional force, to place the separating pawl 3 in a state out of regulation. (b) From this state, when started feeding the following sheet P (c), by applying action of a feed roller 2 with the separating pawl 3 left as held in a state not into contact with the sheet P, a several number of sheets are returned to a condition regulated by the separating pawl 3 (d), (e). Next, the separating pawl 3 is released from a release cam, to energize the sheet by a pawl spring with the support point 3a serving as the center, so as to start separating action.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus for automatically separating and feeding sheets one by one.

[0002]

2. Description of the Related Art Conventionally, in recording devices such as printers, copying machines, and facsimiles, in addition to plain paper, thick paper such as postcards and envelopes and special sheets such as plastic thin plates are used as sheets. The sheets are fed by hand one by one, or automatically and continuously fed by a sheet feeding device.

FIG. 18 shows an example of a recording apparatus integrated with a sheet feeding apparatus. In the figure, the recording apparatus is equipped with a sheet feeding apparatus 1 that separates the sheets P and supplies them one by one, a recording unit 25 that records image information on the fed sheets P, and the like.

FIG. 19 is a vertical cross-sectional side view of the sheet feeding device. The sheet P on the pressure plate 6 can be pressed against a roller roller 46 coaxial with the feeding roller 2 by a pressure spring 7 and its corners. A separation claw 3 is provided on the part.

Further, the leading end of the sheet P is abutted on the lower guide portion 5a of the base 5 within an appropriate range of angles α to β.

The weak sheet P is subjected to the action of being fed to the downstream side by the rotation of the feeding roller 2 and the resistance of the separating claw 3. Only the first sheet P in contact with the feeding roller 2 overcomes the resistance of the separating claw 3 and is separated and fed, and then fed to the recording unit 25.

A strong sheet P such as thick paper (envelope, postcard, etc.) is difficult to be separated by the separation claw 3 because the deflection necessary for separation from the separation claw 3 does not occur near the separation claw 3. . Therefore, for the strong sheet P, the separating claws 3 are released from the corners of the sheet P, and the sheet is separated and fed by the following means.

[0008] The stiff seat restricts the progress of the sheet P toward the downstream side by abutting against the lower guide portion 5a of the base 5. In order to release the sheet P from this regulation, the sheet P that overcomes the waist strength of the sheet P is bent to resist the frictional resistance generated at the contact portion between the tip of the sheet P and the lower guide portion 5a of the base 5. Therefore, a conveyance force sufficient to send the sheet P to the downstream side is required. At this time, the first sheet P, which is in contact with the feeding roller 2, receives the conveying force directly from the feeding roller 2. Further, the second and subsequent sheets P are indirectly applied with the frictional force acting on the sheets P as a conveying force. Then, the lower guide portion 5a of the base 5 has a distance from the feeding roller 2 and an abutting angle with the sheet P so that only the conveying force directly received from the feeding roller 2 is a restriction that can open the sheet P. Has been set. Therefore, it is possible to separate the sheets P one by one. After that, the sheet P is fed to the recording unit 25.

Further, in the case where the sheet P on the stacking means of the sheet feeding apparatus is regulated by the separating claw 3 and separated and fed,
In the system in which the separation claw 3 is intermittently urged to the sheet P, the separation claw 3 moves the sheet P on the stacking means to the sheet P immediately before or at the same time as the rotation of the feeding roller 2, or the pressure plate 6 moves the sheet. The separation claw 3 is urged to the sheet P at the timing of urging P to the feeding roller 2. Further, in the method of urging the separation claw 3 toward the sheet P by operating a lever or the like when setting the sheet, the urging state is continued until the next sheet setting.

[0010]

However, in the above-described conventional sheet feeding apparatus, the following problems remain.

In the sheet conveying control of the recording apparatus at present, the conveying direction of the sheet is not limited to the upstream side to the downstream side, but the sheet may be conveyed to the upstream side in the sheet conveying direction (reverse conveying). . In such a case, the succeeding sheets stacked on the stacking means of the sheet feeding device are
Due to the frictional force with the sheet being conveyed, the sheet is moved to the upstream side from the normal stacking state, and the regulation of the separation claw is released. If the succeeding sheets are fed in this state, the sheets that are out of the regulation of the separation claw will pass through the front surface of the separation claw and will be fed in a state where the separation of each sheet is not achieved. Occurs.

[0012]

The present invention solves the above problems. For that purpose, the sheet stacking means, the feeding roller for feeding the sheet, and the sheet pressure contacting means for pressing the sheet to the feeding roller are provided, and the separation claw for controlling the corner portion of the recording medium is used to remove the sheet from the sheet stacking means. In a sheet feeding device that separates sheets one by one and sends out the separated sheets, in the feeding device in which the separation claw can switch between a biased state and a de-energized state with respect to the stacked sheets, the separation claw is attached to the sheet. The present invention provides a sheet feeding device characterized in that the force is applied after the start of movement of the sheet.

[0013]

According to the above construction, the sheet stacking means, the feeding roller for feeding the sheets, and the sheet pressure contacting means for pressing the sheet against the feeding roller are provided, and the separation claw for controlling the corner portion of the recording medium is used. A sheet feeding device that separates sheets one by one from a sheet stacking unit and sends out the separated sheets, wherein the separating claw can switch between a biased state and a biased release state with respect to the stacked sheets, When the separation claw is urged to the sheet after the sheet starts to move, so that the sheet is conveyed to the upstream side in the sheet conveying direction (reverse conveyance),
Subsequent sheets stacked on the stacking means of the sheet feeding device are moved to the upstream side from the normal stacked state by the frictional force with the sheet being conveyed, and from the state where the separation claw is out of regulation. When feeding is started, the sheets on the downstream side of the normal stacking state first return to the position where they are regulated by the separation claws, and then the separation claws are urged, so it is possible to separate the sheets one by one. The double feed can be reliably prevented.

[0014]

【Example】

(First Embodiment) Next, an embodiment of the sheet feeding apparatus according to the present invention will be described with reference to the drawings. In this embodiment, a sheet feeding device provided in an inkjet recording device will be described. 1 is a perspective explanatory view showing a schematic configuration of an inkjet recording apparatus, FIG. 2 is a front view of a feeding apparatus, FIGS. 3 and 4 are side views showing a drive transmission system of the feeding apparatus, and FIGS. FIG. 7 is a side view of the feeding device, FIG. 7 is a cross-sectional explanatory diagram of the inkjet recording device, FIGS. 8 and 9 are explanatory diagrams of a feeding roller, FIGS. 10 to 14 are explanatory diagrams showing a feeding operation, and FIG. 15 is an inkjet recording device. 3 is a flowchart showing the control operation of FIG.

First, a schematic structure of an ink jet recording apparatus will be described with reference to FIGS. The present embodiment is a recording device integrated with a sheet feeding device, and is equipped with a sheet feeding device 1, a sheet feeding unit, a sheet discharging unit, a carriage unit, a cleaning unit, and the like. Hereinafter, these configurations will be described.

First, the structure of the sheet feeding device 1 will be described. The sheet feeding device 1 is at an angle of 30 ° as shown in FIG.
It is attached to the device body with an angle of 60 °,
The set sheet P is configured to be discharged horizontally after recording. As shown in FIG. 2, the sheet feeding device 1 includes a feeding roller 2, a separating claw 3, a movable side guide 4,
Base 5, pressure plate 6, pressure plate spring 7, drive gear (input gear 8
a, idler gears 8b, 8c, 8f, clutch gear 8
e, feeding roller gear 8d), release cam 9, claw spring 1
0, a release lever 11, a release cam 12 and the like (see FIGS. 3 and 4). Since the release cam 9 pushes the pressure plate 6 down to the position shown in FIG. 5, the sheet P is separated from the feeding roller 2.

With the sheet P set, the drive of the conveying roller 14 described later is transmitted to the feeding roller 2 and the release cam 9 by the drive gears 8a to 8e. When the release cam 9 moves away from the pressure plate 6, the pressure plate 6 rises to the position shown in FIG. 6, the feeding roller 2 and the sheet P come into contact with each other, are picked up as the feeding roller 5 rotates, and are separated by the separating claw 3. Separated one by one. The separated sheet P is sent to the paper feeding unit 13 described later. Feed roller 2 and release cam 9
Rotates once until the sheet P is fed to the paper feeding unit 13, and the feeding roller 2 is deactivated in the state where the pressure plate 6 is released to the feeding roller 2 again, and this initial state is maintained.

As shown in FIG. 7, the paper feeding section 13 includes a conveying roller 14, a pinch roller 15, and a pinch roller guide 1.
6, pinch roller spring 17, PE sensor lever 18, P
An E sensor 19, a PE sensor spring 20, an upper guide 21, a platen 22 and the like are provided. The sheet P sent to the paper feeding unit 13 is guided by the platen 22, the upper guide 21, and the pinch roller guide 16 and is sent to the nip portion between the transport roller 14 and the pinch roller 15. This roller pair 1
The PE sensor lever 18 is provided on the upstream side of the sheet conveying direction of the sheets 4 and 15, and is rotated by the leading edge of the sheet P to release the light shielding of the PE sensor 19 (photo sensor) and detect the leading edge of the sheet P. It is a standard for determining the recording start position of the sheet P. The pinch roller 15 is pressed by the conveying roller 14 by urging the pinch roller guide 16 by the pinch roller spring 17, and is driven by the rotation of the conveying roller 14 to generate the conveying force of the sheet P. There is. The transport roller 14 and the pinch roller 15
The sheet P conveyed in between is driven by the LF motor 23 to rotate the conveying roller 14 and the pinch roller 15 and is conveyed by a predetermined amount on the platen 22 to the recording start position. Then, the recording head 24 is configured to perform recording based on predetermined image information.

The recording head 24 records an ink image on the sheet P conveyed by the conveying roller 14 and the pinch roller 15. As a recording means in this apparatus, an inkjet recording method is used in which ink is ejected from a recording head to perform recording. That is, this recording head has a fine liquid discharge port (orifice), a liquid passage and an energy acting portion provided in a part of this liquid passage, and energy generation for generating droplet forming energy for acting on the liquid in the acting portion. Equipped with means.

As an energy generating means for generating such energy, a recording method using an electromechanical transducer such as a piezo element, electromagnetic waves such as a laser are irradiated to generate heat, and droplets are ejected by the action of the heat generation. There are a recording method using an energy generating means, a recording method using an energy generating means for heating a liquid and discharging the liquid by an electrothermal converter such as a heating element having a heating resistor.

Among them, in a recording head used in an ink jet recording method for ejecting a liquid by thermal energy, liquid ejection ports (orifices) for ejecting recording liquid droplets to form ejection liquid droplets are arranged at high density. Therefore, it is possible to perform high-resolution recording.
Among them, the recording head using the electrothermal converter as the energy generating means can easily be made compact, and has the advantages of the IC technology and the microfabrication technology, which have been remarkably improved in technology and reliability in the recent semiconductor field. This is advantageous because it can be used in two parts, high-density mounting is easy, and the manufacturing cost is low.

The recording section 25 includes a carriage 26 to which the recording head 24 is attached as shown in FIG.
A guide shaft 27 for reciprocally scanning 6 in a direction perpendicular to the sheet conveying direction and a rear end of the carriage 26 are held,
Guide 2 for maintaining the distance between the recording head 24 and the sheet P
8. Timing belt 30 for transmitting drive of carriage motor 29 to carriage 26, and timing belt 30
It is equipped with an idle pulley 31 that stretches, a flexible board 32 for transmitting a head drive signal from an electric board to the recording head 24, and the like. The recording head 24 is a replaceable recording head that is configured integrally with an ink tank, and scans integrally with the carriage 26 to record an ink image on the sheet P conveyed on the platen 22.

As shown in FIG. 1, the discharge sheet portion 33 includes a discharge sheet roller 34, a transmission roller 35 for transmitting the drive of the conveying roller 14 to the discharge sheet roller 34, a spur 36 for assisting discharge of the sheet P, and a discharge roller 36. Equipped with a sheet tray 37 etc. The sheet discharge tray 34 and the spur 36 are used to discharge the sheet P after recording without soiling the recording surface.
Dispose of the sheet on 7.

The cleaning unit 38, as shown in FIG. 1, is a pump 39 for cleaning the recording head 24.
And a cap 4 for suppressing the drying of the recording head 24.
0 and driving from the conveyance roller 14 is performed by the sheet feeding device 1.
And a drive switching arm 41 for switching to the pump 39. The drive switching arm 41 is in the position shown in FIG. 1 except during feeding and cleaning, and the planetary gear (not shown) that rotates around the axis of the transport roller 14 is fixed at a predetermined position. The drive of 14 is not transmitted to the pump 39 and the sheet feeding device 1. When the drive switching arm 41 is moved in the direction of arrow A in FIG. 1 by moving the carriage 26, the planet gears move in accordance with the forward / reverse rotation of the transport roller 14, and the sheet feeding is performed when the transport roller 14 rotates in the forward direction. The drive is transmitted to the feeding device 1, and the drive is transmitted to the pump 39 during reverse rotation.

An LF for driving the conveying roller 14 and the like
A carriage motor 29 that drives the motor 23 and the carriage 26 uses a stepping motor that rotates a predetermined angle in accordance with a signal sent from a driver (not shown).

Further, the feeding roller 2 is provided with a sensor plate 42 having a radius smaller than the diameter of the feeding roller rubber 2a attached around the feeding roller 2. The sensor plate 42 is notched at all, and only when the feeding roller 2 and the release cam 9 are at the initial position for releasing the pressure plate 6 shown in FIG. 5, the electric board 4 shown in FIG.
The roller sensor 44 made of a photo interrupter or the like directly provided on the light source 3 is configured to be in a light transmitting state without being shielded. By detecting the state of the sensor plate 42, the angular position of the feeding roller 2 and the phase of the feeding roller 2 can be aligned, and the angular position of the release cam 9 that is interlocked can be detected. The timing of control in the sequence can be timed.

Next, the structure of the sheet feeding device 1 will be described in detail. As shown in FIG. 2, the sheet feeding device 1 has a base 5 to which each component is attached to form a unit. The sheet feeding apparatus 1 according to the present exemplary embodiment includes a sheet P.
The right side plate 5b of the base 5 is based on one side of the
Is the seat standard. Further, the base 5 is provided with a lower guide portion 5a, which works as an auxiliary supporting function of the sheet support by the separating claw 3 for a weak sheet such as thin paper and has a strong stiffness such as thick paper. For the seat,
It fulfills the function of supporting the sheet and the function of separating the sheets one by one by regulating the tip of the sheet.

In the base 5, the pressure plate 6 can be retracted as shown in FIG. 5, and a recess for forming a pressure plate spring 7 is formed at a position substantially facing the roller portion 2b of the feeding roller 2. The pressure plate 6 is connected to the base 5 by pressure plate shafts 6a formed on the upper portions of both side surfaces as shown in FIG. 5, and is attached so as to be rotatable around the pressure plate shaft 6a. Further, as shown in FIG. 2, the feeding roller 2 of the pressure plate 6 is
A separation pad 45 made of a material having a relatively large coefficient of friction such as an artificial leather is provided at a position opposite to, so as to prevent double feeding and the like when the number of stacked sheets P is small. A movable side guide 4 that can slide to the left and right is attached on the pressure plate 6 so that sheets P of different sizes can be set on the sheet reference surface.

Both ends of the feeding roller 2 are held by the base 5 and are rotatably attached. This feeding roller 2
As shown in FIG. 8, it is an integrally molded product made of plastic or the like, which is composed of a roller portion 2b and a shaft portion 2c, and a feeding roller rubber 2a for conveying the sheet P is provided around the roller portion 2b. The roller portion 2b has a D-shaped cross section (or a half-moon shape), and roller rollers 46 having a radius smaller than the radius of the feeding roller rubber 2a attached to the feeding roller 2 by 0.5 to 3 mm are provided on the outer sides of the roller portion 2b. It is provided to prevent image contamination or displacement of the feeding roller 2 that occurs when the sheet P touches the feeding roller rubber 2a of the feeding roller 2 except during feeding.

As shown in FIG. 2, two roller portions 2b are attached to the shaft portion 2c and are fixed at positions of about 40 mm and about 170 mm from the sheet reference, respectively. Therefore, the A4 size or the like is conveyed by the two roller portions 2b, and the postcard or the like is conveyed only by the one roller portion 2b on the sheet reference side. Ribs 2d having a radius larger than that of the feeding roller rubber 2a are provided on both side surfaces of each roller portion 2b.
The area (hereinafter referred to as the “separation area”) that has been set is shown in FIG.
As shown in FIG. 9A, the roller portion on the sheet reference side has a circumferential distance of 1 mm, and as shown in FIG. 9B, the roller portion 2b of the other feeding roller 2 has a distance of 3 mm, and the respective separated areas have the same radius. Then, the central position angle (α °) of each area is matched on the feeding roller 2.

The drive switching arm 41 of the cleaning section 38 is moved by the carriage 26 in the direction of arrow A,
When the transport roller 14 is rotated in the normal direction, a planet gear (not shown) moves and meshes with the input gear 8a shown in FIG. 4, whereby the drive is transmitted to the sheet feeding apparatus 1. The input gear 8a
Can transmit the drive to the feeding roller gear 8d coupled to the feeding roller 2 via the idler gears 8b and 8c, and rotate the feeding roller 2 to convey the sheet P. Further, the feeding roller gear 8d includes a clutch gear 8e,
The drive is transmitted to the release cam 9 via the idler gear 8f. At this time, the feeding roller 2 and the release cam 9 are configured to be in phase with each other for each rotation, and in the state where the pressure plate 6 shown in FIGS. 4 and 5 is released, the feeding roller 2 is shown in FIG. As shown in the drawing, the cutout portion (half-moon portion) is configured to face the pressure plate 6.

The release cam 9 is shaped so as to release the pressure plate 6 only during the central angle of the meniscus portion of the feeding roller 2 of about 120 °, and the outside of the crescent portion of the feeding roller 2 faces the pressure plate 6. Always use sheet P or pressure plate 6 and 200g-5
It is configured to contact with each other at a pressure of 00 g. Further, the release cam 9 releases the pressure contact of the pressure plate 6 by pressing down the pressing portion 6b of the pressure plate 6 protruding from the hole formed in the right side plate 5b of the base 5 as shown in FIG. At this time, the pressure plate cam 47 attached to the base 5 shown in FIG.
The cam 6c on the side close to the push-down portion 6b of the pressure plate is pushed down, and the pressure plate cam 47 rotates about the fulcrum 47a.
Pushes down the cam 6d.

As described above, the push-down portion 6 at the end of the pressure plate 6
Even if b is pushed down, the pressure plate 6 does not tilt with respect to the base 5,
The pressure is released almost in parallel. A clutch spring 48 is provided in the center of the clutch gear 8e, and is indicated by an arrow B in FIG.
The spring is fitted in the direction in which it is tightened so that it does not reverse.

The separating claw 3 has a fulcrum 3a as shown in FIG.
Can be rotated around the center of the sheet P and is biased by the claw spring 10 against the sheet P or the pressure plate 6 at 20 g to 100 g. The separation claw 3 is for separating a so-called plain paper sheet P when it is fed. As shown in FIG. 2, it is provided only on the sheet reference side and covers the corners of the sheet P in a triangular shape. It has a unique shape. The sheets P can be separated one by one by receiving resistance at the triangular portion of the separation claw 3.
Further, when separating thick paper or the like other than plain paper, the lower guide portion 5a of the base 5 is not attached to the sheet P by the separating claw 3 (see FIG. 5).
It is possible to separate them one by one by using the resistance of the lower guide portion 5a by abutting against each other.

The release lever 11 and the release cam 12 are shown in FIG.
As shown in, it is provided coaxially with the release cam 9. The release lever 11 and the release cam 12 are not interlocked with the release cam 9 and are driven independently to allow the user to set the sheet P. The release lever 11 and the release cam 12 are connected via a gear, and the release lever 11 has three positions of a feed position, a thick paper set position, and a plain paper set position, and each position is about 20 ° to 50 °.
It is provided at angular position intervals of °. This release lever 1
Corresponding to 3 positions of 1, the release cam 12 is about 90
The gear ratios of the two are set so that they rotate in degrees.

At the feed position, the release cam 12 pushes down only the push-down portion 6b of the pressure plate 6, and therefore does not act on the push-down portion 3b of the separation claw 3. It is in this position during normal feeding.

In the thick paper position, the release cam 1
2 pushes down only the push-down portion 3b of the separation claw 3,
The separating claw 3 is lowered along the pressure plate 6, and the separating claw 3 is moved to the sheet P.
You can set thick paper so that it does not hang over.

In the plain paper setting position, the release cam 12 pushes down both the push-down portion 6b of the pressure plate 6 and the push-down portion 3b of the separation claw 3, so that the separation claw 3 floats up on the pressure plate 6 and the separation claw 3 is placed on the sheet. The plain paper can be set by hanging it on the corner of P.

The above-mentioned gear group (excluding the feeding roller shaft), the separating claw 3, the release lever 11, the release cam 12 and the like are provided on the shaft arranged on the right side plate 5b of the base 5. It is mounted rotatably around the axis.

Next, a process of stabilizing the posture of the sheet after the feeding is started due to the effect of the separated area of the sheet feeding apparatus 1 will be described. First, as shown in the sheet feeding apparatus 1 of the present invention, when the separating claw 3 that regulates the leading end of the sheet P is present only on one side, the stacked state of the sheets P is as shown in FIG. With the fulcrum as the fulcrum, the side without the separating claw 3 easily falls and is easily set. From this state, the feeding roller 2
Is rotated and the sheet P supported by the pressure plate 6 is pressed against the feeding roller 2 to start feeding.

Next, as shown in FIG. 11, as the rotation of the feeding roller 2 progresses, the sheet P begins to come off from the separating claw 3. FIG.
2 shows the state after the separation by the separation claw 3 is completed. At this point, the sheets P are still inclined as in the stacked state. After the separation by the separation claw 3 is completed, the ribs 2d of the respective feeding rollers 2 start to contact the sheet P, and the feeding roller rubber 2a and the sheet P are separated from each other. Since the rib 2d is formed of a plastic low friction member integrally with the feeding roller 2, the frictional force generated between the sheet P being fed and the sheet P stacked on the pressure plate 6 is fed. Inside sheet P
The friction force generated between the feeding roller 2 and the feeding roller 2 becomes larger, and the sheet P being fed is stopped. In the present embodiment, the rib 2d serves both as a separating means and a regulating means for regulating the movement of the sheet P.

Since the distance between the feeding roller rubber 2a and the sheet P is set longer in the other feeding roller 2 than the feeding roller 2 on the sheet reference side, as shown in FIG. The sheet P being fed rotates around the roller portion 2b on the side far from the sheet reference, and the side of the sheet P on the sheet reference side is abutted against the right side plate 5b of the base 5 which is the guide means. In this way, when the sheet P is tilted counterclockwise by the time the feeding roller rubber 2a is separated from the sheet P, the sheet P is rotated clockwise due to the difference in the separation area width between the two roller portions 2b, When the side of the sheet P on the sheet reference side is abutted against the right side plate 5b of the base 5,
A force that rotates counterclockwise is generated, and the force overcomes the frictional force between the sheet P in the stacked state and the sheet P being fed,
When both the roller portions 2b are in the slip state, the sheet P is corrected in parallel with the feeding direction.

If the sheet P is tilted in the clockwise direction before the feeding roller rubber 2a is separated from the sheet P, the sheet P is further rotated in the clockwise direction due to the difference in the separation area width between the two roller portions 2b. When the roller portion 2b reaches both of the separated areas and the sheet P is in the slip state, a force for rotating the side of the sheet P on the sheet reference side in the counterclockwise direction from the right side plate 5b of the base 5 is generated. The force overcomes the frictional force between the sheet P in the stacked state and the sheet P being fed, and the sheet P is corrected in parallel with the feeding direction.

Further, by slightly advancing the timing at which the separated areas of the two roller portions 2b deviate from the sheet P on the sheet reference side, when the side of the sheet P on the sheet reference side is abutted against the right side plate 5b of the base 5. The counterclockwise rotational force that is received prevents the right side plate 5b from being separated.

As shown in FIG. 10, the difference in the slip amount of the roller portion 2b is equal to the gap t (about 1 mm) caused by the inclination of the sheet P caused by the separation claw 3 supporting only one side of the sheet P and 2 The rotation amount of the sheet P required to set t to 0 was calculated from the distance between the individual roller portions 2b, and the above setting was performed based on the calculated rotation amount.

Next, the control operation of the sheet feeding apparatus 1 will be described with reference to the operation state shown in FIG. 14 along the flowchart shown in FIG. The control operation of the sheet feeding device 1 can be roughly classified into a case where the feeding roller 2 is at a predetermined initial position and a case where there is a trouble that the feeding roller 2 is not at the initial position. First, the control when the feeding roller 2 is at the predetermined initial position will be described.

FIG. 15 is a flow chart showing the feeding operation control of the sheet feeding apparatus of the present invention. When a signal indicating that feeding is started is transmitted in FIG. 15, the carriage 26 is moved in step S1 to switch the drive. Arm 4
1 so that the drive of the conveying roller 14 can be transmitted to the sheet feeding apparatus 1 (hereinafter, this moving position will be referred to as ASF).
Called position). Next, in step S2, the state of the roller sensor 44 is determined. If the feeding roller 2 is located at the initial position, the process proceeds to step S3, and if not, the process proceeds to step S26. When the feeding roller 2 is at the initial position, the feeding roller 2 is rotated in step S3, and the process proceeds to step S4 to proceed to the sensor plate 4.
L after detecting edge 2 and detecting in step S5
By accurately controlling the angular position of the feeding roller 2 by counting (N1) the drive pulse of the F motor 23,
It is possible to perform accurate control.

When the feeding roller 2 rotates about 60 ° and the circular portion of the feeding roller rubber 2a comes to a position facing the sheet P, the releasing cam 12 rotating in conjunction with the feeding roller 2 is rotated.
By releasing the pressure plate 6, the feeding roller rubber 2a and the sheet P are pressed against each other by the urging force of the pressure plate spring 7, so that the conveyance force of the sheet P is generated (see FIG. 14A). Next, in step S6, the detection of the leading edge of the conveyed sheet P is detected by P
This is performed by the E sensor 19, and the process proceeds to step S7 to store the LF pulse count N1 when the sheet front end is detected as N2.

Next, in step 8 and step S9, when (predetermined pulse X) <N2 <(predetermined pulse Y), it is determined that the normal state is reached, and the process proceeds to step S10 to move the feeding roller 2 The cutout portion (half-moon portion) is rotated to the initial position where the cutout portion faces the sheet P. In this operation, the release cam 12 pushes down the push-down portion 6b of the pressure plate 6 again, so that the pressure plate 6 can be released again (see FIG. 14B). When the rotation of the feeding roller 2 is completed, the leading edge of the sheet P passes between the transport roller 14 and the pinch roller 15. At this time, the leading edge position of the sheet P when the feeding roller 2 is rotated to the initial position is calculated from the drive pulse count N2.

Next, in step S11, when N2 is larger than the predetermined pulse Z, it is determined that the leading end position of the sheet P is on the downstream side of the leading end of the nozzle of the recording head 24, and the process proceeds to step S12 to move the carriage 26. Then, the process proceeds to step S13, the LF motor 23 is rotated in the reverse direction, and the sheet leading end position is returned to 11.5 mm from the conveyance roller 14. The reverse rotation amount of the LF motor 23 is calculated from N2.
At this time, by moving the carriage 26 in step S12, the drive switching arm 41 moves, and the drive of the transport roller 14 cannot be transmitted to the sheet feeding apparatus 1. Next, in step S14, the transport roller 14 is rotated forward to remove the gear backlash, the 0.7 mm sheet P is transported, and the recording head 2
A position with a margin of 1.5 mm can be realized from the nozzle tip of No. 4 (see FIG. 14E), and the feeding is completed.

If N2 is less than the predetermined pulse Z in step S11, it is determined that the leading edge position of the sheet P is upstream of the leading edge of the recording head 24 (FIG. 14 (d)).
In step S15, the carriage 26 is moved, and the transport roller 14 is reversed in this state, whereby the drive switching arm 41 is moved and the transport roller 14 is moved.
The drive of is not transmitted to the sheet feeding device 1.
Next, the process proceeds to step S16, the transport roller 14 is rotated in the forward direction, and the margin of 1.5 m from the nozzle tip of the recording head 24.
The position of m can be set (see FIG. 14E), and the feeding is completed.

Next, in step S9, when the LF pulse count (N2) at the time of detecting the leading edge of the sheet is larger than the predetermined pulse Y, the leading edge of the sheet P is conveyed to the conveying roller 14 and the feeding roller 2 by one rotation. It is determined that a slippage that cannot reach between the pinch rollers 15 occurs between the sheet P and the feeding roller 2, and the process proceeds to step S17.

In step S17, the feeding roller 2 is rotated to the initial position, and further rotated once in step S18. Next, in step S19, the carriage 26 is moved. Next, in step S20, in order to return the leading edge of the sheet P to the transport roller 14, the transport roller 14 is reversed (see FIG. 14C). Along with this, the drive switching arm 41 moves, and the transport roller 14
The drive of is not transmitted to the sheet feeding apparatus 1.
Next, the process proceeds to step S21, the conveyance roller 14 is rotated forward by a constant pulse, and the position of the margin of 1.5 mm can be set from the nozzle tip of the recording head 24 (see FIG. 14E), and the feeding is completed.

If the LF pulse count (N2) at the time of detecting the sheet front end is less than the predetermined pulse X in step S8, the sheet P has been dropped to the downstream side before the feeding is started, and after the sheet front end position is detected. The rib 2d of the feeding roller 2 comes into contact with the sheet P, the feeding roller rubber 2a and the sheet P enter a separated state, and it is determined that the sheet leading end position cannot be accurately recognized, and the process proceeds to step S25.

In step 14, the feeding roller 2 is rotated to the initial position, and the process proceeds to step S26 to move the carriage 26. Next, in step S24, the leading edge of the sheet P is returned to the carrying roller 14, so the carrying roller 14 is reversed (see FIG. 14C). Along with this, the drive switching arm 41 moves, and the transport roller 1
The drive of No. 4 cannot be transmitted to the sheet feeding apparatus 1. Next, in step S25, the conveyance roller 14 is rotated forward by a constant pulse, and the position of the margin of 1.5 mm can be set from the nozzle tip of the recording head 24 (see FIG. 14E), and the feeding is completed.

Next, in step S6, when the PE sensor 19 is not turned on, the process proceeds to step S26, the feeding roller 2 is rotated to the initial position, and then the process proceeds to step S27 to proceed to the roller sensor 44.
When it is confirmed that is turned on, the process proceeds to step S28, and the feeding roller 2 is rotated again. Next in step S29
When the edge of the sensor plate 42 is detected (roller sensor OFF), the process proceeds to step 30 and the drive pulse of the LF motor 23 after the edge is detected is counted (N
By performing 1), the angular position of the feeding roller 2 is accurately managed. Next, if the process proceeds to step S31 and the leading end position of the sheet P is detected (PE sensor ON), the process proceeds to step S23, and if not detected, step S32.
Then, the feeding roller 2 is rotated to the initial position and stopped, the process proceeds to step S33, an error is displayed, and the feeding is finished.

FIG. 16 is a diagram best showing the contents of the present invention, and is a diagram showing the operation timings of the sheet P, the feeding roller 2, and the separating claw 3 in the sheet feeding apparatus 1. First, FIG. 16A shows that the feeding roller 14 has completed the feeding operation.
The sheet P is being conveyed to the downstream side by the conveying force generated between the pinch roller 15 and the pinch roller 15. At this time, the separation claw 3 rotatably supported by the fulcrum 3a is held by the release cam 9 in a state where it is not pressed against the sheet P of the base 5 which is a stacking unit. At this time, when the reverse conveyance control of the sheet to the upstream side is performed, as shown in FIG. 16B, the sheet P on the base 5 that comes into contact with the sheet P being conveyed and several adjacent sheets P rub. It is pushed up by the force. In the worst case, as shown in the figure, the separation claw 3 is out of regulation. As shown in FIG. 16C from this state, when the feeding of the succeeding sheet P is started, the action of the feeding roller 2 is exerted while the separation claw 3 is held in a state of not being pressed against the sheet P. Figure 1
After 6 (d), as shown in FIG. 16 (e), several sheets P that have been pushed up can be returned to the state of being regulated by the separation claw 3. Then, the separation claw 3 is released from the release cam 9, and the claw spring 10 biases the sheet P around the fulcrum 3a, and the separation operation is started as shown in FIG. 16 (f). By this series of operations, it is possible to achieve reliable separated feeding without double feeding.

(Second Embodiment) In the above embodiment, the method of restricting one corner of the sheet P by the separating claw 3 has been described, but as shown in FIG. 17, the separating means for restricting the two corners. The same effect can be obtained when used for.

(Third Embodiment) In the above embodiment, the case where the action of urging the sheet P toward the feeding roller 2 is released by the pressure plate 6 has been described, but in the case where the sheet P is always urged without being released. It is also effective.

(Fourth Embodiment) In the above embodiment, the sheet feeding apparatus mounted on the ink jet recording apparatus is shown. However, the sheet feeding apparatus is not limited to the ink jet recording apparatus and other recording apparatuses, and the sheets are separated and fed one by one. Valid for any model that needs to be sent.

[0061]

According to the present invention, the sheet stacking means has a sheet stacking means, a feeding roller for feeding the sheet, and a sheet pressure contacting means for pressing the sheet against the feeding roller, and the sheet stacking means is provided by a separating claw that regulates a corner portion of the recording medium. Separate the sheets one by one,
In the sheet feeding device that feeds the separated sheets, in the feeding device in which the separation claw can switch the biased state and the biased release state with respect to the stacked sheets, the biasing of the separation claw to the sheet is performed. By performing after the start of the movement, when the conveyance to the upstream side in the sheet conveyance direction (reverse conveyance) is performed, the succeeding sheet stacked on the stacking unit of the sheet feeding device is different from the sheet being conveyed. Even if the sheet is moved from the normal stacking state to the upstream side due to frictional force and the feeding is started from the state where the separation claw is out of regulation, the sheet on the downstream side from the normal stacking state will be regulated by the separation claw first. After returning to the receiving position, the separation claws are urged, so that the sheets can be separated one by one and the occurrence of double feeding can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a recording apparatus showing a first embodiment of the invention.

FIG. 2 is a front view of the sheet feeding device.

FIG. 3 is a side view of the sheet feeding device.

FIG. 4 is a side view of the sheet feeding device.

FIG. 5 is a vertical side view of the sheet feeding device.

FIG. 6 is a vertical side view of the sheet feeding device.

FIG. 7 is a vertical side view of the recording apparatus.

FIG. 8 is a perspective view of the feeding roller unit of the same.

FIG. 9 is a side view of the feeding roller section.

[FIG. 10] Similarly, an operation diagram of the feeding operation

[FIG. 11] Similarly, an operation diagram of the feeding operation

[Fig. 12] Similarly, an operation diagram of the feeding operation.

[FIG. 13] Similarly, an operation diagram of the feeding operation

[Fig. 14] Similarly, an operation diagram of the feeding operation.

FIG. 15 is a control flowchart of the recording device.

FIG. 16 is a sectional view of the sheet feeding device according to the first embodiment of the present invention.

FIG. 17 is a front view of the sheet feeding device according to the second embodiment of the present invention.

FIG. 18 is a perspective view of a recording apparatus integrated with a conventional sheet feeding apparatus.

FIG. 19 is a vertical sectional side view of a conventional sheet feeding device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sheet feeding device 2 ... Feeding roller 2a ... Feeding roller rubber 2b ... Roller portion 2c ... Shaft portion 2d ... Rib 3 ... Separation claw 4 ... Movable side guide 5 ... Base 5a ... Lower guide portion 5b ... Right side plate 6 ... Pressure plate 6a ... Pressure plate shaft 6b ... Pushing down parts 6c, 6d ... Cam 7 ... Pressure plate spring 8a ... Input gears 8b, 8c, 8
f ... Idler gear 8d ... Feed roller gear 8e ... Clutch gear 9 ... Release cam 10 ... Claw spring 11 ... Release lever 12 ... Release cam 13 ... Paper feeding section 14 ... Conveying roller 15 ... Pinch roller 16 ... Pinch roller guide 17 ... Pinch roller Spring 18 ... PE sensor lever 19 ... PE sensor 20 ... PE sensor spring 21 ... Upper guide 22 ... Platen 23 ... LF motor 24 ... Recording head 25 ... Recording section 26 ... Carriage 27 ... Guide shaft 28 ... Guide 29 ... Carriage motor 30 ... Timing Belt 31 ... Idle pulley 32 ... Flexible substrate 33 ... Ejection sheet part 34 ... Ejection sheet roller 35 ... Transmission roller 36 ... Spur 37 ... Ejection sheet tray 38 ... Cleaning part 39 ... Pump 40 ... Cap 41 ... Drive switching arm 42 ... Sensor plate 43 ... Electric board 44 ... Roller sensor 45 ... Separation pad 46 ... Roller roller 47 ... Pressure plate cam

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroyuki Kinoshita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasuhiro Unozawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. (72) Inventor Haruyuki Yanagi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Makoto Karama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koichi Tanno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tetsuo Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. A sheet stacking means, a feeding roller for feeding the sheet, and a sheet pressing means for pressing the sheet against the feeding roller, and a separation claw for regulating a corner portion of the recording medium,
A sheet feeding device that separates sheets one by one from the sheet stacking unit and sends out the separated sheets, wherein the separation claw can switch between a biased state and a biased release state with respect to the stacked sheets. A sheet feeding device, wherein the separation claw is urged to the sheet after the sheet starts to move. 2. A recording apparatus, comprising: the sheet feeding apparatus according to claim 1; and a recording unit configured to record on a sheet fed from the sheet feeding apparatus. 3. The recording apparatus according to claim 2, wherein the recording apparatus is an inkjet recording method in which a recording unit ejects ink in accordance with a signal to perform recording. 4. In the recording apparatus, the recording means energizes the electrothermal converter in response to a signal, and the ink is ejected from the ejection port due to the growth of bubbles caused by heating beyond the film boiling by the electrothermal converter. The recording apparatus according to claim 2, wherein the recording apparatus is an inkjet method for performing recording.