JP2001199568A - Paper feeder and image forming device provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder free from lower carrying force and reduceable in cost and an image forming device provided therewith. SOLUTION: A rotary feeding body 5 having a roller 5c having a cutout portion 5d and an elastic member 67 wound on the outer periphery of the roller 5c is used for feeding sheets stacked on sheet stacking means. Moving means moves the elastic member 67 along the outer periphery of the rotary feeding body 5 while preventing the contact of a worn portion of the elastic member 67 with the sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeder and an image forming apparatus provided with the same, and more particularly to a rotary feeder for feeding sheets stacked on sheet stacking means.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a printer, a copying machine, a facsimile or the like has a paper feeding device for feeding out a sheet stacked on a sheet stacking means by a rotary feeder.

On the other hand, by driving an energy generator of a recording head based on, for example, transferred image information, an image having a dot pattern is recorded on a recording medium (sheet) such as plain paper, a postcard, an envelope, or the like. In recent years, a recording apparatus, which is an example of an image forming apparatus, is required to record on various media such as a coated paper, a resin film-based sheet, and a cloth. There is also a demand for higher performance for reliably feeding these to the rotary feeder.

FIG. 14 is a diagram showing the configuration of such a conventional recording apparatus. In FIG. 14, C is a recording section for performing recording, and B is a paper feeding section for supplying a recording medium (not shown). The paper feeding unit B is provided with a pressure plate 21 on which a recording medium is loaded.
And a feed roller 95 that is a rotary feeder.

Here, the pressure plate 21 is pushed upward in the figure by a pressure plate spring 72.
Is pressed against the top recording medium. Then, when the feeding roller 95 rotates in this state, the recording medium is fed by the frictional force between the feeding roller 95 and the recording medium. Note that a separation pad 73 having a controlled friction coefficient is bonded to the pressure plate 21 so as to come into contact with the lowermost recording medium.

On the other hand, the feed roller 95 has a sector shape in which a part of an arc is cut out, and by having such a shape, the setability of the recording medium is improved. The paper feed roller 95 is usually formed of an elastic member such as a rubber material or an elastomeric mold material. In particular, rubber materials are widely used in recording apparatuses as rubber rollers for paper conveyance.

[0007]

By the way, in such a conventional recording apparatus, the medium conveying force of the feed roller 95 gradually decreases as the medium supplying operation is repeated. The problem appears remarkably depending on the type of the medium, and in the worst case, a problem that the medium cannot be supplied to the recording unit C may occur. For example, coated paper used for color recording in which a plurality of color ink dots are superimposed on each other is coated with silica on the base plain paper surface so that ink penetration can be reduced in the surface direction and increased in the depth direction. , An alumina-based ink receiving layer is applied, and the fine particles of the ink receiving layer
If it adheres to the surface, the conveying force of the feed roller 95 is significantly reduced.

When the number of passed sheets increases, the feeding roller 9
5 wears out. In particular, at the time of feeding, the wear near the fan-shaped end portion where the feed roller 95 starts to press against the recording medium increases, which is a factor of reducing the conveying force required for separation.

Therefore, in order to prevent such a reduction in the conveying force, the surface of the roller is roughened by, for example, grinding with a grinding wheel, or the surface of the roller is provided with irregularities by molding with a mold, so that the paper after repeated paper passing is repeated. It has been conventionally performed to reduce a decrease in the conveying force.

FIG. 15 is a diagram showing the relationship between the conveying force of a feeding roller having different surfaces (flat surface, knurl surface, polishing surface) and the number of coated paper sheets. In the figure, the horizontal axis represents the number of passed sheets and the vertical axis represents the conveying force. Here, the conveying force is a moving force applied to the recording medium by the rotating feeding roller, and the value can be obtained by measuring a force for stopping the movement of the recording medium.

As shown in FIG. 1, the initial conveying force is higher in the order of flat surface roller> knurl surface roller> polishing surface roller. However, as the number of passed sheets increases, the conveying force of the flat surface roller rapidly decreases. Further, as the number of passed sheets increases, the order of increasing the conveying force is: polishing surface roller> knurling surface roller> flat surface roller, and the value becomes constant.

From these results, it can be seen that the polishing surface roller is superior in maintaining the conveying force. However, a polished surface roller that forms a surface shape by polishing the surface with a grinding wheel requires a longer processing time than a knurled surface roller that forms a surface shape with a mold, and therefore costs increase. In addition, it is thin with a thickness of 2 mm or less and 40
In the case of a material having a low hardness of less than or equal to °, there is a problem in that, if the operation takes a long time, the roller bites into the grindstone and cannot be processed, so that mass production is difficult.

Accordingly, the present invention has been made in view of such a situation, and a sheet feeding apparatus and a recording apparatus (image forming apparatus) capable of preventing a reduction in a conveying force and suppressing a reduction in cost. It is intended to provide.

[0014]

According to the present invention, there is provided a sheet feeder comprising: a roller having an outer peripheral surface having a notch; and an elastic member wound around the outer peripheral surface of the roller. In the sheet feeding device configured to feed out the sheets stacked on the stacking unit, a moving unit that moves the elastic member along an outer peripheral surface of the roller unit is provided.

Further, the present invention is characterized in that the moving means moves the elastic member by rotating a cam member pressed against the elastic member at the notch.

Further, according to the present invention, the moving means includes a cam member which presses the elastic member at the notch, and rotates the rotary feeder while pressing the elastic member against the cam member. Thereby, the elastic member is moved.

Further, the present invention is characterized in that the cam member is provided coaxially with a rotation axis of the rotary feeder.

Further, the present invention is characterized in that a concave portion is formed in the notch portion, and the elastic member is pushed into the concave portion of the notch portion by the cam member pressed against the concave portion. is there.

Further, the present invention is characterized in that the cam member is manually rotated.

According to the present invention, there is provided an image forming apparatus including an image forming unit and a sheet feeding device for feeding a sheet to the image forming unit, wherein the sheet feeding device is as described above. It is characterized by the following.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view for explaining the structure of an ink jet recording apparatus which is an example of an image forming apparatus provided with a sheet feeding apparatus according to a first embodiment of the present invention, and FIG. 2 is a side sectional view thereof. is there.

1 and 2, reference numeral 1 denotes an ink jet recording apparatus, and 1A denotes an ink jet recording apparatus main body (hereinafter, referred to as an apparatus main body). The ink jet recording apparatus 1 includes a paper feeding device 11, a paper feeding unit 12, and a paper discharging unit 1.
3, an image forming unit 15, a cleaning unit 16, and the like. The sheet feeding unit 11 feeds the sheets P one by one, and feeds the fed sheets P through the sheet feeding unit 12 to the image forming unit 15. After the image is conveyed to the printer, an image is formed by the image forming unit 15, and thereafter, the image is discharged to the outside of the apparatus by the paper discharge unit 13.

Next, the sheet feeding device 11 and the like will be sequentially described.

First, FIG. 3 and FIG.
This will be described with reference to FIG. The sheet feeding device 11 includes a pressure plate 21 serving as a stacking unit on which the sheet P is placed, and a feed rotator 5 that feeds the sheet P. Here, the pressure plate 21 is rotatably held by the base 20 via a rotation shaft (not shown), and is urged by the pressure plate spring 72 toward the feed rotating body 5. In addition, the portion of the pressure plate 21 facing the feed rotary member 5 is provided with the sheet P when the number of sheets P is reduced.
A separation pad 73 made of a material having a large coefficient of friction, such as an artificial skin, for preventing double feeding of the paper is provided.

The paper feeder 11 is of a one-side reference type. For this reason, a movable side guide 19 for regulating the position of the sheet P is movably provided on the pressure plate 21. A paper end reference PKO is formed on the base 20 as a reference.

Then, such a movable side guide 19
Provided on the pressure plate 21, the side end (the left side in FIG. 3) of the sheet P can be regulated, while the other end (the right side in FIG. 3) can be regulated by the paper reference PKO. The placement position can be regulated even when the size of the sheets P is different.

The base 20 is inclinedly attached to the apparatus main body 1A at an angle of 30 ° to 60 °, and includes a pressure plate 21, a feed rotating body 5, and a pressure plate spring 72.
Etc. are integrally provided. Furthermore, this base 20
A separation claw 17 is rotatable and a claw spring 3
It is attached while being urged to the pressure plate side by 2.

On the other hand, the feed rotary member 5 is an integrally molded product such as plastic made of a shaft portion 5b and a roller portion 5c.
It is rotatably supported by the base 20 via the shaft 5b, and also via the input gear 25, idler gears 26 and 27, and the feed rotator gear 28 connected to one end of the shaft 5b of the feed rotator 5. The rotation is carried out by the driving force of the conveyance roller 36 described later transmitted by the transmission.

The roller portion 5c of the feeding rotary member 5
Has a D-shaped (or half-moon) shape having an outer peripheral surface having a cutout portion, and a feed rotary rubber 67 which is an elastic member for feeding the sheet P is provided on the peripheral surface. ing. Further, a roller roller (not shown) having a radius smaller than the radius of the feeding rotary rubber 67 by 0.5 to 3 mm is provided outside the roller portion 5c. Then, when the sheet is not fed, the roller roller touches the sheet P,
This prevents contamination of the image and displacement of the sheet P.

In this embodiment, two roller portions 5c are provided, and these roller portions 5c are respectively about 40 mm and about 170 m from the paper reference PKO.
It is fixed at a position m meters away. Thereby, the sheet P
Is a A4 size, the sheet P is conveyed by two rollers 5c. If the sheet P is a small size such as a postcard, the sheet P is conveyed by one roller on the paper reference PKO side.

In FIG. 4, reference numeral 21c denotes a pressure plate 2
Reference numeral 29 denotes a push-down portion provided in the input gear 2.
5, a release cam that is rotated by the driving force of the transport roller 36 transmitted through the idler gears 26 and 27 and the feed rotator gear 28 and pushes down the push-down portion 21c. In this state, the pressure plate 21 is pressed down against the urging force of the leaf spring 72 (see FIG. 2). Thus, in the standby state, the contact between the sheet P placed on the pressure plate 21 and the feeding rotary member 5 is released.

On the other hand, when the image forming operation is started and the conveying roller 36 is driven as will be described later, and the feeding rotator 5 and the release cam 29 rotate accordingly, the release cam 29 is pushed from the depressed portion 21c of the pressure plate 21. I'm leaving. As a result, the pressure plate 21 is raised by the urging force of the pressure plate spring 72, whereby the separation claw 17 comes into contact with the sheet P surface.

At the same time, the feed rotator 5 is 200 g to 5 g.
The sheet P comes into contact with the contact force of 00 g, so that the sheet P is picked up and fed with the rotation of the feeding rotating body 5. Then, the picked-up sheets P are separated one by one by a separation claw 17 and sent to the paper feeding unit 12. The feeding rotator 5 and the release cam 29 rotate (one rotation) until the sheet P is fed into the paper feeding unit 12, and the sheet P and the feeding rotator 5 are released from contact with each other again in a standby state (FIG. 2). Paper feed roller 36
The driving force from is cut off.

A clutch spring 77 is provided inside the release cam 29. The direction of the arrow B corresponds to the direction in which the clutch spring 77 is tightened, and the clutch spring 77 does not reverse. ing. Thus, when performing registration or the like, the feeding rotary member 5
As a result, it stops rotating and good registration can be performed.

Next, the paper feeding section 12 will be described with reference to FIGS.

The paper feeding section 12 is attached to the chassis 3 made of a bent sheet metal, and
Roller 36, PE sensor 32, and sheet P
, An upper guide 33, a platen 34, and the like. Here, the transport roller 36 is driven by an LF motor 88 and has a configuration in which an elastic body such as rubber is wound around the surface of a metal shaft. 3 is attached. A transport roller tension spring 381 is provided between the bearing 38 and the transport roller 36 to apply a load during rotation to the transport roller 36 by urging the transport roller 36 to perform stable transport. ing.

The transport rollers 36 include the transport rollers 3.
A plurality of pinch rollers 37 which are pressed against and driven by the pinch roller 6 are provided. Here, the pinch roller 37 is rotatably supported by the upper guide 33 and is held by the pinch roller guide 30 urged in the direction of the transport roller 36 by the pinch roller spring 31. The transport force of the sheet P is generated by pressing the pinch roller 37 against the transport roller 36 by 30.

The pinch roller 37 does not cover the entire area of the sheet P, but is divided and covers only a predetermined area. Therefore, in the present embodiment, a guide 301 for preventing the sheet P from floating is provided on the pinch roller guide 30 in a portion where the pinch roller 37 is not provided. Further, the upper guide 33 is provided with a PE sensor lever 35 for transmitting the leading and trailing edge detection of the sheet P to the PE sensor 32.

The platen 34 is fitted with a transport roller 36 mounted on the chassis 3 and is positioned by a sliding bearing (not shown) and a mounting shaft (not shown) directly mounted on the chassis 3.
A paper holder (not shown) that covers the end of the sheet P is provided on the paper reference side. By providing such a paper holder, the sheet P whose end is deformed or curled is provided.
In this case, the end is raised so as not to interfere with the carriage 50 or the recording head 7.

Next, the image forming section 15 will be described.

The image forming section 15 is provided downstream of the conveying roller 36 in the recording sheet conveying direction, and forms a recording head 7 for forming an image based on image information.
And a carriage 50 for mounting the same. In the present embodiment, an easily replaceable ink jet recording head integrally formed with the ink tank is used as the recording head 7. Here, the recording head 7 causes the ink to boil by applying heat to the ink with a heater or the like, and ejects the ink from the nozzles by a pressure change caused by the growth or shrinkage of bubbles due to the film boiling, thereby forming the ink on the sheet P. An image is formed.

On the other hand, the carriage 50 is driven by a carriage motor 53 attached to the chassis 3 via a timing belt 55 stretched and supported by an idle pulley 56, and also transmits a recording head signal from an electric board 70. A flexible board 57 for transmission is provided.

A guide shaft 5 for reciprocatingly scanning the carriage 50 in a direction perpendicular to the direction in which the sheet P is conveyed.
1 and a guide rail 52 that holds the rear end of the carriage 50 and maintains a gap between the recording head 7 and the sheet P.

The guide shaft 51 is attached to the chassis 3. The guide rail 52 is formed integrally with the chassis 3. In addition, since the guide rail 52 is formed integrally with the chassis 3 as described above, the number of parts and the number of mounting steps can be reduced.
Cost reduction. In addition, since the rigidity of the chassis 3 is increased by bending the guide rail 52, the reliability in terms of strength is improved. Further, when the conventional strength is sufficient, the thickness of the sheet metal forming the chassis 3 can be reduced, so that the cost is further reduced.

Next, the paper discharge unit 13 will be described.

The paper discharge section 13 includes a transmission roller 60 that contacts the transport roller 36, a discharge roller 59 that contacts the transmission roller 60, and a spur 61 that contacts the discharge roller 59.
And When the transport roller 36 is driven, the driving force of the transport roller 36 is transmitted to the discharge roller 59 via the transmission roller 60, so that the discharge roller 59 rotates while the spur 61 is driven to rotate. It has become.

The spur 61 is attached to an integral spur stay 341 provided on the platen 34. By thus providing the spur stay 341 integrally with the platen 34, the spur 61 and the discharge roller 59 Can be managed in the same part, and the dimensional relationship can be stably maintained.

The spur stay 341 is provided with a notch (not shown). By providing such a notch, the carriage 50 has moved to this position when the recording head 7 is replaced. At this time, a space for operating the hook lever 62 for attaching and detaching the recording head 7 is secured.

Next, the cleaning section 16 will be described.

The cleaning unit 16 includes a pump 63 for cleaning the recording head 7, a cap (not shown) for suppressing drying of the recording head 7, and a driving force from the transport roller 36 accompanying the movement of the carriage 50. 3
Drive switching arm 6 that transmits to the paper feeding device 11 or the pump 63 via a planetary gear 66 that rotates about the axis of
5 is provided.

Here, the drive switching arm 65 is
At times other than paper feeding and cleaning, the planetary gear 66 is fixed at a predetermined position so as not to transmit the driving force to the paper feeding device 11 and the pump 63, and the planetary gear 66 is set to a free state as the carriage 50 moves. It has been replaced.

The drive switching arm 6
5 is switched, the planetary gear 66 moves in accordance with the forward rotation and the reverse rotation of the transport roller 36, whereby the driving force is transmitted to the paper feeding device 11 when the transport roller 36 rotates forward, and when the transport roller 36 rotates reversely. The driving force is transmitted to the pump 63.

That is, when the transport roller 36 rotates forward and the planetary gear 66 moves, the planetary gear 66 meshes with the input gear 25 shown in FIGS. 3 and 4, and thereafter via the idler gears 26 and 27. The driving force is transmitted to the feed rotator gear 28, and the feed rotator 5 rotates. Further, a driving force is transmitted to the release cam 29 via the feed rotating body gear 28, and the release cam 29 rotates.

Here, the feed rotary member 5 and the release cam 29
In the standby state, the feeding rotating body 5 having the cutout portion is opposed to the sheet P without contacting the sheet P, and is released as shown in FIG. The cam 29 pushes down the push-down portion 21c to thereby cause the pressure plate 2
Set 1 to a standby state.

Next, the image forming operation of the recording apparatus 1 thus configured will be described.

When the recording operation is started, first, the transport roller 36 rotates forward, and accordingly, the driving force of the transport roller 36 becomes
Planetary gear 66, input gear 25, idler gears 26 and 27
The rotation is transmitted to the feed rotator 5 via the feed rotator gear 28, whereby the feed rotator 5 rotates and the release cam 29 rotates.

When the release cam 29 rotates in this way, the release cam 29
1c, the pressure plate 21 is raised by the pressure plate spring 72, and the separation claw 17 comes into contact with the sheet P surface. At the same time, the feed rotator 5 and the sheet P come into contact with each other, and the sheet P is picked up by the rotation of the feed rotator 5. 12 is sent.

Next, the sheet P sent to the sheet feeding section 12 in this manner is guided by the platen 34, the pinch roller guide 30 and the upper guide 33 and sent to the transport roller 36.
Thereafter, the conveyance roller 36 and the pinch roller 37 are rotated by the LF motor 88 to be conveyed on the platen 34 and conveyed below the recording head 7 of the image forming unit 15. At this time, the PE sensor lever 35 detects the leading end of the conveyed sheet P, whereby the control device (not shown) determines the timing of starting printing of the sheet P.

Next, when the sheet P is conveyed to the predetermined row position where the image is formed by the conveying roller 36 and the pinch roller 37 in this manner, the carriage motor 53 causes the carriage 50 to set the column position (the sheet P) where the image is formed. To a position perpendicular to the conveyance direction of the recording head 7).
Comes to face the image forming position. Then, after that, the recording head 7 discharges ink toward the sheet P by a signal from the electric substrate 70 to form an image. The sheet P on which an image is formed in this manner is conveyed while being sandwiched between the nip between the discharge roller 59 and the spur 61, and is discharged to a discharge tray (not shown).

By the way, the feed rotator 5 whose both ends are held by the base 20 is, for example, an elastic member such as a natural or synthetic rubber material on the outer periphery of a columnar rigid member such as metal or plastic. The configuration is provided. Here, the reason why the core member is a rigid body is to secure the torsional rigidity for transmitting the rotational driving force to the recording medium by reducing the deflection of the core member due to the pressure of the pressure plate applied thereto. If these conditions are satisfied, the core member may be formed integrally with an elastic member.

The relationship between the core member and the elastic member of the feed rotary member is as described above. In other words, the feed rotary member only needs to have at least the outer peripheral portion formed of the elastic member. Therefore, as a method other than press-fitting the elastic member into the core member and fixing the core member without slipping therebetween, the core member is previously set in a mold when molding the rubber which is the elastic member. There is also a method such as integral molding in which rubber is filled around and molded.

By the way, in this embodiment, as shown in FIGS. 5 and 6, the feeding rotating body 5 is composed of several parts to form a unit. That is, as described above, the feed rotary member 5 is an integrally molded product of plastic or the like including the shaft portion 5b and the roller portion 5c having the outer peripheral surface having the notch 5d, and the outer peripheral surface of the roller portion 5c. Has a sheet P
For example, hardness 20 to 40 ° for feeding and transporting
A paper feed rotary rubber 67 which is an elastic member made of a high friction material such as (A scale) EPDM rubber is attached.

The shaft portion 5b is hollow as shown in FIG. 6C, and the shaft 8b is attached to the hollow shaft portion 5b.
0 is inserted coaxially and rotatably. Further, a tension arm 82 which has a cam portion 81 and is a cam member constituting a moving means is attached to a portion of the shaft 80 corresponding to the roller portion 5c.

The shaft 80 is provided with a groove 83 extending in the axial direction, and a projection 84 which fits into the groove 83 of the shaft 80 is provided in a shaft penetration hole (not shown) provided in the tension arm 82. The driving force from the shaft 80 is transmitted to the tension arm 82 by the groove 83 and the projection 84. Further, a concave portion 5c1 is formed in the cutout portion 5d of the roller portion 5c.

Here, as shown in FIG. 6A, the cam 81 of the tension arm 82 is pressed against the feed rotary rubber 67, and the feed rotary rubber 67 is pushed into the recess 5c1. By applying tension to the feeding rotary rubber 67, the feeding rotary rubber 67 can be attached to the outer peripheral surface of the roller portion 5c without any gap.

On the other hand, when the feed rotary member 5 is fixed and the pressure contact by the cam portion 81 is released by rotating only the tension arm 82, there is no tension on the feed rotary rubber 67, as shown in FIG. A gap is formed between the feeding rotary rubber 67 and the outer peripheral surface of the roller portion 5c.

When the tension arm 82 (cam portion 81) is further rotated in a state where the tension to the feed rotary rubber 67 has been lost, the feed rotary rubber 67 moves along the outer peripheral surface of the roller portion 5c. To move. In the present embodiment, the tension arm 82 (cam portion 81) is manually rotated.
A knob 85 having a knurled shape is attached to the surface as shown in FIG.

Next, referring to FIG.
The behavior of the feed rotator rubber 67 when rotates one revolution will be described.

First, as shown in FIG. 7A, the knob 85 is moved in the direction C from the state in which the cam portion 81 is turned upward and tension is applied to the feeding rotary rubber 67 (see FIG. 7).
When the tension arm 82 is rotated clockwise as shown by the arrow, the small diameter portion of the cam portion 81 comes into contact with the feed rotary rubber 67, thereby gradually rotating the feed rotary rubber 67. Tension weakens,
As shown in (b), the feed rotary rubber 67 and the roller portion 5c
A gap S is generated between the outer circumferential surface of the feed roller and the feed rotary rubber 67, and the feed rotary rubber 67 is in a slack state without tension.

Thereafter, when the tension arm 82 is further rotated clockwise while the feeding rotary rubber 67 is loosened, the cam portion 81 is again rotated as shown in FIG. When the tension arm 82 further rotates, the rotation of the cam portion 81 causes the rotation of the feeding rotary rubber 67 to occur due to the frictional force between the cam portion 81 and the feeding rotary rubber 67.
Is transmitted to As a result, when the tension arm 82 rotates 360 degrees and returns to the standby state, the feed rotary rubber 67 moves as shown in FIG.

By moving the feeding rotary rubber 67 in this way, the sheet P (ink-receiving layer) is brought into contact with the portion where the conveying force is reduced due to the attachment or abrasion of the fine particles, especially the sheet P, and the sheet P first comes into contact with the sheet P End 86 of notch 8d
Can be prevented from touching the sheet P, and a decrease in the conveying force of the feeding rotating body 5 can be suppressed. Further, by suppressing the decrease in the conveying force in this way, it is not necessary to use an expensive polishing surface roller, so that the cost can be reduced.

By the way, in the description so far, the tension arm 8 for moving the feeding rotary rubber 67 has been described.
2 has been described as being manually rotated using the knob 85. However, the present invention is not limited to this, and even if the feeding rotator 5 is rotated with the tension arm 82 fixed, the feeding rotator 5 is rotated. The rubber 67 can be moved with respect to the roller 5c.

Next, a second embodiment of the present invention having such a configuration will be described.

In the present embodiment, as shown in FIG. 10, the feed rotator 5 is rotated in the feed direction shown by the arrow from the standby state shown in FIG. When the feed rotator 5 rotates in this way, the feed rotator rubber 67 comes into contact with the small-diameter portion of the cam portion 81, thereby gradually reducing the tension of the feed rotator rubber 67,
Eventually, as shown in (b), a gap S is formed between the feeding rotary rubber 67 and the roller portion 5c, and the loosened state without tension occurs.

When the feed rotator 5 is further rotated in the feed direction while the feed rotator rubber 67 is loosened, the cam portion 81 is rotated as shown in FIG. When the feed rotator rubber 67 moves by the frictional force at this time and the feed rotator 5 rotates 360 degrees and returns to the standby state, the feed rotator 5 rotates as shown in FIG. Body rubber 67
Moves.

As described above, even if the feed rotary member 5 is rotated with the tension arm 82 fixed, the feed rotary rubber 67 can be moved with respect to the roller portion 5c, thereby always lowering the transport force. It is possible to realize the sheet feeding device 11 including the feeding rotating body 5 with a small number.

By the way, in this embodiment, in order to rotate the feeding rotary body 5 with the tension arm 82 fixed, the paper feeding device 11 includes a tension arm fixing means for fixing the tension arm 82, and a feeding rotation unit. Body gear 2
There is provided a feeding rotating body driving means configured to be able to select transmission and cutting of the drive after 9.

FIG. 11 is a view for explaining such a feeding rotator driving means. The feeding rotator driving means includes a gear meshing with the feeding rotator gear 28 as shown in FIG. 96, a planetary gear 95 meshing with the gear 96, and a first solenoid 100a for controlling the position of the planetary gear 95.
, The planetary gear 95 is attached and the restriction groove 100d
And a planetary gear arm 100e having

In such a feed rotator driving means, the drive transmitted to the feed rotator 5 through the feed rotator gear 28 normally causes the planetary gear to travel through the same feed rotator gear 28. The power is transmitted to the gear 95. However, at this time, as shown in FIG. 12 and FIG.
Since the solenoid pin 100c of (a) acts on the restricting groove 100d of the planetary gear arm 100e by the spring 100b, the position of the planetary gear 95 is restricted, and even if the feed rotating body 5 rotates forward or backward, the drive is not Is not transmitted to the part.

On the other hand, the first solenoid 100a operates,
When the solenoid pin 100c moves in the direction of arrow f as shown in FIG. 12B, the planetary gear arm 100e whose restriction has been released moves in the direction of arrow e by the urging force of the urging means (not shown). The planet gear 95 meshes with the release cam gear 29.

As a result, when the feed rotating body 5 rotates forward and backward, the planetary gear 95 rotates forward and reverse, and the release cam gear 29 rotates.
Rotates forward and backward. When the release cam gear 29 rotates in the normal or reverse direction, the press plate 21 is released or released, and the press plate 21 is moved to the feeding rotating body 5.
To be closer to or farther from.

FIG. 13 is a view showing the structure of the tension arm fixing means. The tension arm fixing means includes a disk 90 fixed to the shaft 80 and provided with a restriction groove 91, and a restriction groove of the disk 90. And a second solenoid 92 having a solenoid pin 94 locked to the solenoid 91.

In such a tension arm fixing means, usually, as shown in FIG.
The solenoid 92 is not operating, so that the solenoid pin 94 is pushed into the second solenoid against the solenoid spring 93 so that the shaft 80 and the disc 90 can rotate. It has become.

On the other hand, when the tension arm 82 is fixed, the second solenoid 92 is operated. As a result, when the disk 90 rotates together with the shaft 80, the solenoid pins 94 of the second solenoid 92 are opened by opening the solenoid spring 93 as shown in FIG.
Of the disk 9 at a predetermined regulating position.
0 can be held.

Therefore, at the time of feeding, FIG.
By operating the first and second solenoids 92 and 100a from the state shown in FIG. 13B and FIG.
And the tension arm 82 can rotate together.

Further, for example, in the state of FIG. 12B and FIG. 13A, the first and second solenoids 92, 1
When the operation of the first solenoid 100a is stopped, the solenoid pin 100c of the first solenoid 100a is stopped as shown in FIG.
Acts on the restriction groove 100d of the planetary gear arm 100e by the spring 100b. For this reason, the position of the planetary gear 95 is regulated, and even if the feed rotator 5 rotates forward or backward, the drive is not transmitted to other parts. That is, only the feed rotating body 5 can be rotated without driving other parts.

On the other hand, the solenoid pin 94 of the second solenoid 92 enters the regulating groove 91 of the disk 90 due to the urging force of the solenoid spring 93 as shown in FIG. The disk 90 can be held at a predetermined restriction position. Thus, the feeding rotating body 5 can be rotated with the tension arm 82 fixed, and the above-described operation can be achieved automatically without manual operation.

[0089]

As described above, according to the present invention, the elastic member is wound around the outer peripheral surface of the rotary feeder having the notch, and the elastic member is moved along the outer peripheral surface by the moving means. By moving the elastic member, the worn portion of the elastic member can be prevented from contacting the sheet, so that a reduction in the conveying force can be prevented and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a configuration of an ink jet recording apparatus as an example of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the ink jet recording apparatus.

FIG. 3 is a front view of a sheet feeding device of the ink jet recording apparatus.

FIG. 4 is a right side view of the paper feeding device.

FIG. 5 is a left partial sectional view of the sheet feeding device.

FIG. 6 is a view for explaining the structure of a feeding rotating body in the paper feeding device.

FIG. 7 is a left side view of the paper feeding device.

FIG. 8 is a partial plan view of the paper feeding device.

FIG. 9 is an explanatory diagram of an operation of a feeding rotating body in the sheet feeding device.

FIG. 10 is an explanatory diagram of an operation of a feeding rotator in a sheet feeding device according to a second embodiment of the present invention.

FIG. 11 is a diagram for explaining a feeding rotating body driving unit provided in the paper feeding device.

FIG. 12 is a view for explaining the operation of the feeding rotating body driving means.

FIG. 13 is a view for explaining tension arm fixing means provided in the paper feeding device.

FIG. 14 is a side cross-sectional view showing a configuration of a conventional sheet feeding device.

FIG. 15 is a diagram illustrating a relationship between a conventional conveying force of a feeding roller having different surfaces and the number of coated paper sheets.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 ink jet recording apparatus 1A apparatus main body 5 feeding rotating body 5b shaft section 5c roller section 5c1 concave section 5d notch section 11 paper feeder 15 image forming section 21 pressure plate 67 paper feed rotating body rubber 80 shaft 81 cam section 82 tension arm P sheet

Claims (7)

[Claims] 1. A sheet loaded on a sheet loading means by a rotary feeder having a roller portion having an outer peripheral surface having a notch portion and an elastic member wound around the outer peripheral surface of the roller portion. A sheet feeding device configured to send out, wherein a moving unit that moves the elastic member along an outer peripheral surface of the roller unit is provided. 2. The paper feeder according to claim 1, wherein said moving means moves the elastic member by rotating a cam member pressed against the elastic member at the notch. apparatus. 3. The moving means includes a cam member that presses against the elastic member at the notch, and rotates the rotary feeder while pressing the elastic member against the cam member. 2. The paper feeding device according to claim 1, wherein the elastic member is moved. 4. The sheet feeder according to claim 2, wherein the cam member is provided coaxially with a rotation axis of the rotary feeder. 5. A recess is formed in the notch,
5. The paper feeding device according to claim 2, wherein the elastic member is pushed into the concave portion of the cutout portion by the cam member that presses the elastic member. 6. The sheet feeding device according to claim 2, wherein the cam member is manually rotated. 7. An image forming apparatus comprising: an image forming unit; and a sheet feeding device that feeds a sheet to the image forming unit, wherein the sheet feeding device is any one of claims 1 to 6. An image forming apparatus, comprising: