JPH09132336A - Paper feeding conveyor device in image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent continuous feed by making a succeeding paper sheet, remaining on a separating member, interfere with a conveyance regulating member even in a state of an open conveying path being formed by releasing the pressure contact of a paper base and a separating member with the peripheral surface of a feed roller by an energization release means. SOLUTION: In a stage of the tip of an uppermost paper sheet 22A being fed into a driven roller part, a separating member 26 is pressed by a cam body and put in an energization released state of being separated from a feed roller 23 so as to form an open conveying path 62. At this time, a roller member 61 is displaced directly downward by its own weight so as to narrow the space of the open conveying path 62. In association with this, an uppermost paper sheet 22B out of remaining paper sheets after the separative feed of the paper sheet 22A is going to slide onto the separating member 26, but since the paper sheet 22B comes to interfere in contact with the vicinity of a lower end part 61b of the roller member 61 having entered into the open conveying path 62, the paper sheet 22B is placed in a state of hardly receiving the conveying force of the feed roller 23 so as to prevent the continuous feed of the paper sheet 22B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding and conveying device in an image forming apparatus such as an electrophotographic printer.

[0002]

2. Description of the Related Art FIG. 21 shows an outline of a general paper feeding / conveying device in an image forming apparatus of this type. Many sheets of paper 10
0 is a paper tray 10 supported by a fulcrum 101 so as to be swingable.
The paper tray 102 is stacked and held on the paper tray 2, and the paper tray 102 is urged by the paper tray urging means 103 so that the leading end of the uppermost paper sheet comes into pressure contact with the outer peripheral surface of the paper feed separation roller 104. Also,
A separating member 106 including a pad 105 having a high coefficient of friction is provided on the downstream side of the paper tray 102 in the paper conveying direction, and the separating member urging means 107 is used to provide the pad 105.
The separating member 106 is urged so that the sheet is pressed against the outer peripheral surface of the sheet separating roller 104. These paper trays 10
2. The separation / feed unit A is formed by the sheet base urging unit 103, the sheet feeding / separating roller 104, the separating member 106, and the separating member urging unit 107.

Further, the conveyance path 1 between the transfer section 110 and the separation sheet feeding section A formed by the photoconductor 108 and the transfer roller 109.
11 includes a drive conveyance roller 112 and a driven conveyance roller 1
A conveyance section B is provided by a roller pair with 13.

Here, the separating / feeding section A feeds and separates the uppermost paper among the many stacked sheets 100 from the sheet feeding / separating roller 104.
The function of sending to the separating member 106 by the frictional force with
The friction force between the separating member 106 and the paper 100 causes the paper 10
The separating member 106 urges a frictional force that is greater than the frictional force between 0s so that only one sheet, which is the uppermost sheet, is separated and sent to the conveyance section B, which is the next step. Further, the transport section B transfers the sheet 100 at the same speed as the photoconductor 108 or slightly faster than the photoconductor 108.
It has a function to transfer to 0. The carrying section B is usually called a registration section, and if the feeding from the carrying section B to the transfer section 110 is unstable, problems such as transfer blurring occur.

In order to achieve such a function, in the prior art, the separate sheet feeding section A and the transport section B have separate drive transmission mechanisms (for example, electromagnetic clutches), and FIG.
As shown in FIG. 1, it is configured as a separate unit.

In regard to the separation / feeding section A, however, when the topmost one sheet is sent to the conveyance section B, the drive transmission is released, and in order to avoid a load on the conveyance section B, the paper feed / separation roller 10
4 has a half-moon shape, or a one-way clutch is inserted on the drive shaft of the paper feed separation roller 104.

However, in the case of the general structure as shown in FIG. 21, since the separating and feeding section A and the conveying section B are separate units, the number of parts is large and the image forming apparatus itself has a large number of parts. It hinders compact design. As for the drive transmission mechanism, an independent drive transmission control mechanism (clutch mechanism, separate drive actuator, etc.) is indispensable because the feed amount and speed are separately controlled on the side of the separate sheet feeding unit A and the side of the conveyance unit B. Become.

In this respect, a paper feeding device which can be made compact is disclosed in Japanese Utility Model Laid-Open No. 6-39841. According to the publication, a half-moon-shaped sheet feeding roller that is rotatably driven so as to send out the uppermost sheet of the stacked sheets, and a conveyance roller that is rotatably mounted on the shaft of the sheet feeding roller. , A feeding roller that is rotatably driven so as to sandwich the fed sheet between the feeding rollers and feed the sheet, and a separating member that can be pressed into contact with the sheet feeding roller. One sheet is formed by the sheet feeding roller and the separating member. Sends out only the paper (separate paper feed),
This one sheet is configured to be conveyed (conveyed) to the next step by a conveyance roller / conveyance roller. That is, the separating and feeding function and the conveying function are realized around the feeding roller.

However, in the case of the paper feeding device described in Japanese Utility Model Laid-Open No. 6-39841, although it is made compact, a transport roller driven separately from the paper feeding roller is indispensable, and in terms of the number of parts. Is almost the same as the general one shown in FIG. This is because the paper feed roller has a half-moon shape in order to reduce the load in the carrying state, and therefore it is inevitable that the feed roller is rotationally driven.

In consideration of such inconvenience, by using only one rotationally driven roller, it is possible to achieve both the separating and feeding function and the conveying function, and to achieve compactness and reduction of the number of parts. A paper feeding / conveying device as shown in 22 is considered. In general, a paper feed roller 121 that is driven to rotate in synchronization with the image forming unit side is provided, and the paper tray 122 and the separating member 1 are provided on the outer periphery of the paper feed roller 121.
23 and the driven conveyance roller 124 in this order, and the paper base 122, the separating member 123, and the driven conveyance roller 124 are biased by the biasing means 125 to 127 so as to be pressed against the paper feed roller 121. ing.
Here, the paper tray 122 is swingably supported around a fulcrum 128, and holds a large number of paper sheets 129 in a stacked state. Further, the separating member 123 has a pad 130 having a high friction coefficient, which is in direct contact with the outer peripheral surface of the sheet feeding roller 121, and is provided so as to be capable of coming into contact with and separating from the sheet feeding roller 121 about a fulcrum 131.

As a result, the paper 129 on the paper tray 122 is
The topmost sheet of the sheet is pressed against the sheet feeding roller 121, and is separated into only one sheet when it is sent out by the sheet feeding roller 121 and passes between the sheet feeding roller 121 and the separating member 123 (pad 130). Will be fed. This one sheet of paper 129 is fed by the paper feed roller 121 and the driven conveyance roller 124.
The next step (transfer section) receives the conveying force by passing through
Transported to

According to the sheet feeding / conveying device as shown in FIG. 22, the sheet feeding roller 121 and the driven conveying roller 124 have a conveying function up to the next step. Therefore, a pair of registration rollers such as the rollers 112 and 113 is provided as a separate unit. It is not necessary to provide the above, and it greatly contributes to the compact design of the entire image forming apparatus.

By the way, when the paper feeding / conveying device as shown in FIG. 22 is further considered, the paper feeding roller 121 takes charge of both the separation and feeding and the conveyance to the next process, so that a compact design = the paper feeding roller 121 In consideration of the reduction in diameter, it is necessary to rotate at least one rotation. This means that the paper feed roller is configured as a round roller,
At the stage of conveyance by the paper feed roller 121 and the driven conveyance roller 124, the paper tray 122 and the separating member 123 are set to the paper feed roller 1.
When it is in pressure contact with 21, the conveyance load (particularly the separating member 1
23 has a frictional separation function, and thus has a large load), which impairs the transportability to the next process.
At the time when the 24 sheets are separated and fed, it is necessary to release the bias to separate the paper tray 122 and the separating member 123 from the paper feed roller 121. The pressure contact / separation of the paper tray 122 and the separating member 123 with respect to the paper feed roller 121 is as follows.
For example, it can be realized by using a cam (not shown) rotatably provided on the shaft of the paper feed roller 121.

[0014]

However, in the paper feeding / conveying device as shown in FIG. 22, the following inconvenience occurs due to the separating operation of the paper tray 122 and the separating member 123 with respect to the paper feeding roller 121. There is. FIG.
Referring to FIG. 23, after separating the uppermost one sheet of paper 129A by the separating member 123 (FIG. 23A), the bias of the paper tray 122 and the separating member 123 is released by the rotation of the cam. (FIG. 23 (b)) Therefore, the separating member 123
The sheet 129 remaining on the upper side (that is, several sheets fed from the sheet table 122 are left untreated) is the separating member 123.
Being released from the urging force of, the behavior may become unstable. That is, some of the upper sheets 129 on the sheet tray 122 remain in the transport surface inlet 132 of the apparatus main body, and the remaining sheets 1
The sheet 29 moves down along with the sheet wall 122 along the inlet wall surface 133. As a result, after the sheet 129A has passed, the uppermost sheet 129B among the remaining sheets 129 slides downward in the open transport path between the sheet feeding roller 121 and the separating member 123 due to its own weight (see FIG. 23 (c). )), The paper feed roller 121 and the paper 1 that are constantly rotating in synchronization with the image forming unit.
When a part of 29B comes into contact, the carrying force may be received, and may be carried as it is to the driven carrier roller 124 side on the downstream side (FIG. 23 (d)). Such a sheet 129
Since the conveyance of B is performed at a timing different from the normal continuous printing process (such a conveyance is called "continuous feeding").
It will cause a paper jam.

In view of this, the present invention employs a compact and small number of parts, in which a paper table, a separating member, and a driven conveying roller are sequentially provided around one rotationally driven paper feeding roller, and the paper table and An object of the present invention is to provide a sheet feeding and conveying device capable of eliminating continuous feeding of subsequent sheets due to de-energization of a separating member.

[0016]

According to a first aspect of the present invention, a paper feed roller that is coupled and driven in synchronization with an image forming unit, a paper tray on which a plurality of sheets are stacked, and a paper on the paper tray. A paper table urging means for urging the paper table so that the paper table comes into pressure contact with the outer peripheral surface of the paper feeding roller; A flexible separating member, a separating member urging means for urging the separating member so that the separating member is in pressure contact with the outer peripheral surface of the sheet feeding roller, and the separating member is positioned downstream of the separating member in the sheet conveying direction. A driven conveying roller that rotatably contacts the outer peripheral surface of the sheet feeding roller; a roller urging unit that urges the driven conveying roller so that the driven conveying roller presses the outer peripheral surface of the sheet feeding roller; A drive system different from the drive system of the paper roller And a paper table cam portion that is controlled to rotate in the same direction as the paper feeding roller and that rotates to move the paper table in a direction approaching the paper feeding roller by the urging force of the paper table urging means. , A cam having a separating member cam portion for moving the separating member in the direction of approaching the sheet feeding roller by the rotation of the separating member urging means by its rotation, and after the cam has rotated a predetermined angle, Urging releasing means for releasing pressure contact between the paper base and the separating member with respect to the outer peripheral surface of the paper feed roller,
The conveyance path when the separating member is biased is not hindered, and a conveyance restricting member that is located in the open conveyance path when the biasing of the separating member is released and interferes with subsequent sheets is provided.

Therefore, after separating the uppermost paper fed from the paper tray by the separating member, the biasing release means releases the pressure contact between the paper tray and the separating member against the outer peripheral surface of the paper feed roller, and opens and conveys the paper. Even if the path is formed, the succeeding paper remaining on the separating member interferes with the transport restricting member, so that continuous feeding is prevented. When the separating member is urged, that is, when the sheet is separated and fed, the conveyance regulation member does not hinder the conveyance path, so that the separation regulation function is not impaired by the conveyance regulation member.

According to a second aspect of the present invention, there is provided a sheet feeding / conveying device in the image forming apparatus according to the first aspect, wherein:
A roller member that is rotatably and vertically movable on both sides of the separating member contact area on the axis of the paper feed roller, and is displaced downward by its own weight when the separating member is de-energized and part of it is opened and conveyed. It is located on the route.

Therefore, at the time of releasing the biasing force of the separating member, the roller member is displaced downward by its own weight in conjunction with the releasing action of the biasing member, and a part of the roller member is positioned in the open conveyance path, so that the succeeding sheet is moved to the downstream side. Even if it tries to proceed, it interferes with a part of the roller member and its continuous feeding is prevented. When biasing the separating member,
Since the roller member is also pushed up together with the pressure contact of the separating member with the sheet feeding roller, the separating and feeding function is not impaired by the roller member.

According to the third aspect of the invention, the roller member of the sheet feeding and conveying device in the image forming apparatus according to the second aspect is moved downward by its own weight to the position where it comes into contact with the separating member.

Therefore, the open conveyance path when the biasing of the separating member is released is regulated in a wedge shape because the roller member descends to the position where it comes into contact with the separating member, and the succeeding sheet passes under the roller member. Since it is difficult to slip through, the effect of preventing continuous feeding is enhanced.

According to a fourth aspect of the invention, the outer peripheral surface of the roller member of the sheet feeding and conveying device in the image forming apparatus according to the second aspect is processed into an uneven shape.

Therefore, when the succeeding sheet interferes with the roller member when the biasing of the separating member is released, the braking performance is enhanced by the uneven shape of the outer peripheral surface, and the effect of preventing continuous feeding is enhanced.

According to a fifth aspect of the present invention, in the sheet feeding / conveying device of the image forming apparatus according to the second aspect, a groove-like portion is dropped toward the separating member so that the roller member cuts off the open conveying path and moves downward. have.

Therefore, when the biasing of the separating member is released, the open conveying path is regulated to have the blocking wall because the roller member descends to the position where it falls into the groove portion of the separating member. The effect of preventing delivery is further enhanced.

According to a sixth aspect of the present invention, there is provided a sheet feeding / conveying device in the image forming apparatus according to the first aspect, wherein:
It is formed so as to project from the main body of the device toward the conveying path around the paper feed roller, and is hidden in the separating member conveying surface when the separating member is energized, and is exposed from the separating member conveying surface when the separating member is de-energized. It has a stopper wall.

Therefore, after separating the uppermost sheet fed from the paper tray by the separating member, the pressing release means releases the pressure contact between the paper tray and the separating member against the outer peripheral surface of the paper feed roller, and the open conveyance is performed. Even if the path is formed, the succeeding sheets remaining on the separating member interfere with the stopper wall exposed from the conveying surface of the separating member, so that continuous feeding is prevented. When the separating member is biased, that is, at the time of separating and feeding, the stopper wall is hidden in the separating member conveying surface, so that the separating and feeding function is not impaired by the stopper wall. Since the stopper wall is integrally formed with the apparatus main body by being formed so as to project from the apparatus main body side, the number of parts is not increased in order to prevent continuous feeding.

According to a seventh aspect of the invention, the stopper wall of the sheet feeding and conveying device in the image forming apparatus according to the sixth aspect is a sheet guide member for forming a sheet guide path between the separating member and the driven roller. It is formed integrally.

Therefore, the structure for preventing continuous feeding is further simplified.

[0030]

FIG. 1 shows a first embodiment of the present invention.
Or, it demonstrates based on FIG. As one of the embodiments, the sheet feeding and conveying apparatus of the present invention is applied to a compact electrophotographic printer 1 as shown in FIG.

In this printer 1, an image forming section 4 centering on a drum-shaped photosensitive member 3 is arranged in the center of the apparatus main body 2. The image forming section 4 includes a photoconductor 3, a charging unit 5, an optical writing unit 6, a developing unit 7, a transfer unit including a transfer roller 8, which are sequentially arranged around the photoconductor 3 according to an electrophotographic process. , Cleaning means 9. Reference numeral 10 is a toner tank, and 11 is a waste toner tank. A paper discharge tray 16 formed on a top plate 15 of the apparatus, in which a fixing unit 13 and a paper discharge roller 14 are sequentially arranged on the downstream side of the transfer unit 12 formed by the photoconductor 3 and the transfer roller 8 in the paper conveyance direction. In succession. The device top plate 15 is openable / closable with respect to the device body 2 about a support shaft 17.

Further, a paper feeding / conveying device 21 is arranged upstream of the transfer section 12 in the paper conveying direction. The paper feeding / conveying device 21 sequentially separates and feeds one sheet from a large number of sheets 22 and conveys the one sheet 22 to the transfer unit 12 without a registration roller. The structure is similar to that shown in FIG.

The surface of the photoconductor 3 which is driven to rotate in the direction of the arrow is uniformly charged by the charging means 5, and an electrostatic latent image is formed by receiving irradiation of laser light from the optical writing means 6. The electrostatic latent image is visualized as a toner image by the developing means 7. When the toner image passes through the transfer unit 12 by the transfer roller 8, the toner image is transferred onto the paper 22 fed and conveyed by the paper feed / conveyance device 21. Paper 2 with transfer image
The sheet 2 is conveyed to the fixing unit 13, undergoes a fixing process, and then is ejected to the sheet ejection tray 16 by the sheet ejection roller 14.

The basic structure of the paper feeding and conveying device 21 will be described with reference to FIG. First, a paper feed roller 23 having a diameter similar to that of the photoconductor 3 is provided. This paper feed roller 23
Is made of rubber such as EPDM, urethane, or silicon, and is driven to rotate in the clockwise direction together with the shaft 24 made of metal or resin. According to the direction, the paper tray 25 and the separating member 2
6, the driven conveyance roller 27 is provided in this order.

First, the paper tray 25 holds a large number of paper sheets 22 in a stacked state. For example, the paper tray 25 is formed of a resin material and swings and pivots about a support shaft 28 with respect to the apparatus main body 2. It is supported freely. Here, this paper stand 2
In order to realize the compactness of the printer 1, 5 is installed in a state of being greatly inclined so as to be steep, and the lower end side of the uppermost paper side of the paper 22 on the paper table 25 is the outer periphery of the paper feed roller 23. Positioned to touch the surface.
Therefore, when the paper table 25 swings around the support shaft 28, the lower end side of the stacked paper is displaced so as to come into contact with and separate from the outer peripheral surface of the paper feed roller 23. In addition,
As shown in FIG. 4, a pad portion 29 made of cork or rubber is provided at the most downstream portion of the paper tray 25 in the paper feeding direction. Further, the most downstream portion of the paper tray 25 in the paper feeding direction is formed in an open state without a wall, and the lower end portion of the stacked papers 22 has an inlet wall surface (not shown ...) Formed on the apparatus main body 2 side. It is regulated by the inlet wall surface 133 in FIG. 23). Further, the paper table 25 is provided with a compression spring 30 as a paper table urging means provided on the lower surface of the paper table 25.
Is urged in the direction of being pressed against the paper feed roller 23.

The separating member 26 is arranged immediately below the paper tray 25 and immediately below the paper feed roller 23, and is rotatable about a fulcrum 31 on the downstream side. It is formed by a body 32 and a pad portion 33 made of cork or rubber embedded on the base body 32 at an upstream position in contact with the outer peripheral surface of the paper feed roller 23. A notch 32 a for disposing the driven transport roller 27 is formed on the downstream side of the base body 32.
Therefore, when the separating member 26 is rotated by the fulcrum 31, the surface of the pad portion 33 side is displaced so as to come into contact with and separate from the outer peripheral surface of the paper feed roller 23. Further, the separating member 26 is urged in a direction in which it is pressed against the sheet feeding roller 23 by a compression spring 34 as a separating member urging means provided on the back surface of the pad portion 33.

The driven conveyance roller 27 is shown in FIGS.
As shown in FIG. 3, a U-shaped groove 35 provided in the apparatus main body 2 is arranged in the notch 32a region of the base body 32 so as to be movable in the vertical direction (direction in which the paper feed roller 23 is contacted and separated). The sheet feeding roller 2 is provided by a leaf spring 36 as a roller urging means for urging the shaft portions at both ends thereof upward.
It is urged in the direction in which it is pressed against 3. The leaf spring 36 is inserted into a support portion 37 formed in the apparatus main body 2 and the pawl 36a is retained in the hole 37a by being locked.

The shaft 24 of the paper feed roller 23 is shown in FIG.
As shown in FIG. 5, the drive gear 38 is fixed and is drivingly connected to the drive transmission mechanism 40 for the photoconductor 3 on the image forming section 4 side through the idle gear 39. Therefore, the paper feed roller 23 is constantly driven to rotate in synchronization with the photoconductor 3.

Further, the driven conveying roller 27 is always in pressure contact with the paper feed roller 23, but the paper tray 25 and the separating member 26 are not always in pressure contact with the paper feed roller 23. The paper table 25 and the separating member 2
There is provided a cam 41 for pressing and separating 6 and 6 from the paper feed roller 23. The cam 41 is provided on the shaft 24 for the paper feed roller 23 and is rotatable with respect to the shaft 24. This cam 41 has a cam body 42, a cam body 43, and a biased body 4 having a shape as shown in FIG.
4, the locked body 45, and the toothless gear 46 are integrally formed in the axial direction.

Here, the cam body 42 forms a cam portion for the separating member, and at a position facing the cam body 42, the cam contact 32b axially projected from the base body 32 of the separating member 26. Are integrally formed. Further, the cam body 43 forms a paper table cam portion, and a cam contact 25a protruding from one lower end of the paper table 25 is integrally formed at a position facing the cam body 43. . That is, the cam body 42 and the cam body 43
Have almost the same shape, but the cam contacts 32b, 2
The outer peripheral portions 42a and 43b are formed so as to be displaced in the circumferential direction by an angle of 5a apart. The tooth-missing gear 46 is rotated by the idle gear 39, and has a tooth-missing portion 46a in a part thereof, and when the machine is stopped or waiting, as shown in FIG. The cam 4 so that it stops at a position facing the idle gear 39.
1 is controlled so that the driving force is not received. The locked body 45 has such a toothless gear 46.
Is for restricting the stop position of the lock stopper, and a locking step portion 45a is formed at a predetermined position, and the rotation stop claw 47 is locked. The rotation stop claw 47 is rotatably supported around a support shaft 48, and a tension spring 49 is provided.
Is urged in a direction to be locked by the locking step portion 45a. An actuator 50a of a solenoid 50 is locked to a part of the rotation stop claw 47, and when the solenoid 50 is energized and the actuator 50a is attracted, the rotation stop claw 47 is locked. It is set to rotate in a direction away from the step portion 45a. Further, the biased body 44 is always receiving a biasing force in the clockwise direction by the coil spring 51 as a biasing body being locked, and when the cam 41 rotates, the idle gear 39 has the toothless portion. Gear part 46b of gear 46
It is for starting that meshes.

In order to realize the operation described below, the acting forces of the springs 51 and 49 are: a. (The force with which the coil spring 51 urges the biased member 44 in the feed roller conveyance direction (the moment when the driving force from the idle gear 39 side is lost))> (The cam members 42 and 43 are the separating members 26,
Force to push down the paper tray 25) b. (Force of pulling the plunger 50a when the solenoid 50 is energized)> (Force of the tension spring 49 to stop the rotation stop claw 47)> (Force of the coil spring 51 to urge the biased body 44 in the sheet feeding roller conveying direction) It has been set to have a size relationship.

A paper feeding operation using the cam 41 will be described with reference to FIGS. 8 and 10 to 122.

Before Starting Paper Feeding Operation (During Stop and Standby) First, FIG. 10 shows a state (home position) during stop and standby of the machine. That is, the image forming unit 4 and the paper feed roller 23 are stopped before the sheet passing operation is started, and the position of the tooth-chipped gear 46 is controlled so that the tooth-chipped part 46 a is stopped at a position facing the idle gear 39. (Fig. 10 (a)
In addition, the paper tray 25 and the separating member 26 are in a biased release state in which they are separated from the outer peripheral surface of the paper feed roller 23. The separating operation of the separating member 26 is performed by the outer peripheral portion 42a of the cam body 42 abutting against the cam contact portion 32b of the base body 32 of the separating member 26 and pushing down as shown in FIG. Although not shown in FIG. 10, the separating operation of the paper tray 25 is performed by the outer peripheral portion 4 of the cam body 43.
3a is brought into contact with the cam contact portion 25a of the paper tray 25 and pushed down (see FIG. 8). With such a separated state, the user can easily replenish and replace the sheet 22.

At this time, the cam 41 itself is urged by the coil spring 51 in the rotation direction of the paper feed roller 23.
The rotation stop claw 47 is locked to the locking step portion 45a of the locked body 45 (see FIG. 10B), and the postures of the paper tray 25 and the separating member 26 at the home position are maintained. . The rotation stop claw 47 is rotatable around the support shaft 48, but at the home position, it is engaged with the locking step portion 45a by a tension spring 49 stretched in a direction that restricts the rotation of the cam 41. The stopped state is maintained.

At the time of starting the paper feeding operation At the time of starting the paper feeding operation based on the paper feeding start signal, the image forming unit 4 and the paper feeding roller 23 are rotationally driven in synchronization with a common motor as a drive source. In this state, the attitude control is performed such that the toothless portion 46a of the toothless gear 46 in the cam 41 faces the idle gear 39 that transmits the driving force to the paper feed roller 23, and the rotation drive mechanism 40 is used. The driving force is not transmitted to the cam 41 and the cam 41 does not rotate. That is, the driving force of the motor is not transmitted to the cam 41.

On the other hand, when a paper feed start signal is output, the solenoid 50 is energized and its plunger 50a is attracted, so that the rotation stopping pawl 47 is rotated counterclockwise against the tension spring 49. As a result, the locking step portion 45
When the cam 41 is separated from a (see FIG. 11B), the rotation restricting state of the cam 41 is released. Therefore, the cam 41, which is constantly urged in the clockwise direction by the coil spring 51 via the urged body 44, starts to rotate in the clockwise direction when the rotation restriction state is released (see FIG. 11B). ). With such clockwise rotation of the cam 41, the gear portion 46b of the toothless gear 46 starts to mesh with the idle gear 39 (see FIG. 1).
1 (a)), and thereafter, the cam 41 rotates by receiving the driving force from the idle gear 39 side. That is, the rotation of the cam 41 is started by using the suction operation of the plunger 50a of the solenoid 50 locked by the rotation stop claw 47 as a power source.

With the clockwise rotation of the cam 41 as described above, the outer peripheral portion 42a of the cam body 42 becomes smaller in diameter, so that it separates from the cam contact portion 32b of the base body 32 in the separating member 26 and becomes the cam contact portion 32b. The contact state of is released (see FIG. 11C). Therefore, the separating member 26 is pressed against the outer peripheral surface of the sheet feeding roller 23 by the urging force of the compression spring 34. Although not shown in FIG. 11, the press contact operation of the paper tray 25 is such that the outer peripheral portion 43a of the cam body 43 has a smaller diameter and is separated from the cam contact portion 25a of the paper tray 25, and the contact state with the cam contact portion 25a is released. As a result, the paper table 25 is pressed against the outer peripheral surface of the paper feed roller 23 by the urging force of the compression spring 30.

As a result, the pad portion 29 of the paper tray 25, the pad portion 33 of the separating member 26, and the driven conveying roller 27 are brought into pressure contact with the outer peripheral surface of the paper feeding roller 23 so that the paper can be fed. Therefore, the sheets 2 stacked on the sheet tray 25 are
In the case of No. 2, after the topmost sheet is called by the sheet feeding roller 23, only the topmost sheet 22A is separated and fed by passing between the sheet feeding roller 23 and the pad section 33, and is driven and conveyed. It is sent to the roller 27 side. The paper 22 sent to the driven carrying roller 27 is carried to the transfer unit 12 in synchronization with the rotation of the photoconductor 3 while receiving the carrying force of both rollers 23 and 27 because the paper feeding roller 23 is constantly driven to rotate. To be done.

After the start of the paper feeding operation After the start of the paper feeding operation, when the leading edge of the paper 22 fed from the separating member 26 side is sent to a position slightly beyond the driven transport roller 27, the paper tray 25 is again started. Discrimination member 2
6 and the paper feed roller 23 from the paper feed roller 23.
The cam 41 rotates once until the tooth-missing portion 46a of the tooth-missing gear 46 faces the idle gear 39 in order to control so as not to impose a load on the driven conveying roller 27 (see FIG. 12A). .

That is, when one sheet 22A that has been separated and fed enters the contact portion between the feed roller 23 and the driven conveying roller 27, the outer peripheral portions 42a and 43a of the cam bodies 42 and 43 respectively contact the cam contact portions. The paper table 25 and the separating member 26 are pressed against each other by the compression spring 3 as they come into contact with the parts 32b and 25a and push them down.
It is pushed down so as to be separated from the outer peripheral surface of the paper feed roller 23 against the rollers 4, 30. In this state, one sheet of paper 22A
Is transported to the transfer unit 12 by the paper feed roller 23 and the driven transport roller 27, and is used for the transfer operation. Therefore, when the paper 22 is transported by the paper feed roller 23 and the driven transport roller 27, the pad portions 29 and 33 do not become a transport load.

When the rotation of the cam 41 progresses and the tooth-missing portion 46s of the tooth-missing gear 46 faces the idle gear 39, the driving force from the idle gear 39 side is cut off, so that the rotation of the cam 41 stops, but The coil spring 51 with respect to the urging body 44
The cam 41 continues to rotate in the direction of rotation of the paper feed roller because the urging force of (4) is applied (see FIG. 12B). During the rotation by the biasing force of the coil spring 51, the rotation stop claw 47, which receives the biasing force of the tension spring 48, locks on the locking step 45a of the locked body 45. The rotation operation of is completely stopped.

In this way, the same state as before the start of the sheet feeding operation described above (at the time of stop and standby) is returned. However,
Paper feeding is in progress and the motor, and hence the drive transmission mechanism 4
0, the paper feed roller 23 continues to rotate through the idle gear 39. After the trailing end of the fed and conveyed sheet 22 passes through the sheet feeding roller 23 and the driven conveying roller 27, the next sheet 22 is fed and conveyed at a predetermined interval. When it is not necessary to feed and convey the succeeding paper, the motor continues to rotate at least until the paper 22 exits the paper discharge roller 14.

In the basic structure for carrying out such a paper feeding / conveying operation, in the paper feeding / conveying device of the present embodiment, a pair of left and right resins which are positioned on the shaft 24 of the paper feeding roller 23 and serve as a conveyance regulating member. A roller member 61 made of is provided. These roller members 61 are located on both sides of the region where the paper feed roller 23 abuts on the separating member 26.
It has a diameter slightly larger than 3, and has a round hole 61a having a diameter larger than the diameter of the shaft 24 at the center thereof, so that it is rotatable and vertically movable with respect to the shaft 24. That is, the roller member 61 is the separating member 2
6 is pushed up by the separating member 26 when it is in pressure contact with the paper feed roller 23, and when the separating member 26 is displaced downward, it is displaced downward so as to hang on the shaft 24 by its own weight. The amount of downward displacement of the roller member 61 corresponds to the difference between the diameter of the shaft 24 and the diameter of the round hole 61a.

In such a structure, the separating member 26
When the pad portion 33 of the roller is pressed against the outer peripheral surface of the sheet feeding roller 23 to perform the separate sheet feeding operation, the roller member 61 moves the separating member 2
It is pushed up by 6 and does not hinder the separation and feeding operation of the uppermost sheet 22A.

On the other hand, when the leading end of the uppermost sheet 22A is fed to the driven conveying roller 27, the separating member 26 is pressed by the cam body 42 and is released from the sheet feeding roller 23 in the bias release state. As a result, an open transport path 62 is formed between the paper feed roller 23 and the separating member 26. At this time, interlocking with the release of the biasing force of the separating member 26, the roller member 61 is displaced downward by its own weight in the downward direction,
As shown in FIG. 1, the lower end portion 61b side thereof is in a state of existing in the open conveyance path 62. Thereby, the lower end portion 61
The interval of the open transport path 62 is narrowed in the portion where b is present. Accordingly, after separating and feeding the paper 22A, even if the uppermost paper 22b among the remaining papers tries to slide on the separating member 26, the lower end portion 61b of the roller member 61 that has advanced into the open transport path 62. Since they will come into contact with each other and interfere with each other, it becomes difficult to receive the carrying force of the paper feed roller 23, and continuous feeding of the paper 22B is prevented.

The roller member 61 is not limited to the circular shape, but may be a fan shape such as a cam shape.

A second embodiment of the present invention will be described with reference to FIG. The same parts as those shown in FIGS. 1 to 12 are denoted by the same reference numerals, and the description thereof will be omitted (the same applies to the following embodiments). In the present embodiment,
The diameter of the round hole 61a (or the diameter of the roller member 61) is set to a large value so that when the biasing of the separating member 26 is released, the lower end 61b of the separating member 26 is displaced downward to a position where it contacts the pad portion 33. Has been done. That is, the separating member 2
The lower end portion 61b of 6 is provided so as to always come into contact with the pad portion 33 regardless of whether the biasing of the separating member 26 is released.

According to such a configuration, the uppermost sheet 2
When the tip of 2A is fed to the driven transport roller 27, the separating member 26 is pressed by the cam body 42 and is separated from the paper feed roller 23, and is in the urging release state. As a result, an open transport path 62 is formed between the paper feed roller 23 and the separating member 26. At this time, the separating member 26
The roller member 61 is displaced downward by its own weight in a downward direction in association with the release of the urging of the pad portion 33, and the lower end portion 61b side of the pad portion 33 is closed so as to close the open conveyance path 62 in a wedge shape as shown in FIG. Contact. Accordingly, after separating and feeding the paper 22A, even if the uppermost paper 22b among the remaining papers tries to slide on the separating member 26, the lower end portion 61b of the roller member 61 that has advanced into the open transport path 62. Since it comes into contact with the wedge-shaped portion due to and stops due to interference, it becomes difficult to receive the conveying force of the sheet feeding roller 23, and continuous feeding of the sheet 22B is prevented. The function of preventing continuous feeding is greater than in the case of FIG.

A third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the outer peripheral surface of the roller member 61 is formed as the uneven surface 63. As the uneven surface 63, the uneven surface 63a formed in the spur gear shape as shown in FIG. 14A may be the uneven surface 63b formed in the knurled shape as shown in FIG. 14B. May be.

According to this structure, after the sheet 22A is separated and fed, even if the uppermost sheet 22b among the remaining sheets is slipped on the separating member 26 that has been de-energized, the open conveying path 62 is opened. Since it collides with the uneven surface 63a or 63b of the lower end portion 61b of the roller member 61 that has advanced inside and receives interference, it becomes difficult to receive the conveyance force of the paper feed roller 23, and continuous feeding of the paper 22B is prevented. Especially,
When the leading edge of the sheet 22B enters the concave portion of the concave-convex surface 63a or 63b, the state of having high progress prevention capability is provided, and the function of preventing continuous feeding is improved.

In FIG. 14, the example of application to the roller member 61 as shown in FIG. 1 has been described, but the same can be applied to the roller member 61 as shown in FIG.

A fourth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, with respect to the base body 32 of the separating member 26, the groove-like portion 64 is formed at a portion corresponding to the roller member 61, and
It is set so as to fall into the groove portion 64 when it is displaced downward by its own weight. That is, the groove portion 64 is formed by cutting off both ends of the pad portion 33. Further, by increasing the diameter of the round hole 61a of the roller member 61, the amount of downward displacement of the roller member 61 is set to be large.

According to this structure, the separating member 26
When the urging of the roller is released, the roller member 61 is displaced downward by its own weight in the downward direction, and the lower end portion 61b side of the roller member 61 blocks the open transport path 62 and drops to the groove-shaped portion 64 as shown in FIG. The open transport path 62 is closed so as to form a wall. Along with this, even after the sheet 22A is separated and fed, the sheet 22B is slid onto the separating member 26, but the sheet 22B abuts on the blocking wall formed by the roller member 61 and the pad portion 33, receives interference, and stops. So
It becomes difficult to receive the conveyance force of the paper feed roller 23,
Continuous feeding of the paper 22B is prevented. The function of preventing continuous feeding is greater than that of the above-described embodiments.

A fifth embodiment of the present invention will be described with reference to FIGS. First, in the present embodiment, the roller member 61 is not provided, and the paper feed roller 23
The structure on the shaft 24 for use is as shown in FIG. On the other hand, in the device body 2 side, the separating member 26
The paper guide member 66 that forms the paper guide path 65 between the driven conveyance roller 27 and the driven conveyance roller 27 has a three-piece rib shape and the apparatus main body 2
Is formed integrally with the bottom surface of the. That is, the separating member 26
Although the sheet conveying path is largely changed in direction from the driven sheet to the driven conveying roller 27, the sheet guiding member 66 moves the sheet guiding path 65 in the meantime along the outer peripheral surface of the sheet feeding roller 23 to convey the sheet from the separating member 26. The purpose is to make the paper conveyance to the roller 27 smooth.
Such a protruding position of the paper guide member 66 is a notch 32a portion in the base body 32 of the separating member 26.

The upper side of the rising piece on the upstream side of the paper guide member 66 in the carrying direction is a stopper wall 67 which functions as a carrying restricting member. That is, the stopper wall 67 is formed integrally with the paper guide member 66. here,
The height of the stopper wall 67 is such that the separating member carrying surface 68 of the separating member 26 when the separating member 26 is in the urging state.
Although hidden inside, it is set to be exposed above the sorting member transport surface 68 when the sorting member 26 is in the urging release state and the sorting member 26 is displaced downward. That is, the stopper wall 67 is formed so as to be positioned in the open conveyance path 62 when the biasing of the separating member 26 is released.

In such a structure, the separating member 26
20A, when the pad portion 33 is pressed against the outer peripheral surface of the sheet feeding roller 23 to perform the separate sheet feeding operation, as shown in FIG.
The stopper wall 67 forms the separating member transport surface 6 of the separating member 26.
8, which is hidden in the pad portion 8 and the paper feed roller 2
Therefore, there is no problem in the transportability of the sheet 22A that is separated and fed to the driven transport roller 27 side. At this time, the direction of the conveyance path is largely changed from the pad portion 33 to the driven conveyance roller 27, but since the paper guide member 66 forms the paper guide path 65 along the outer peripheral surface of the paper feed roller 23, 22A is smoothly fed to the driven transport roller 27 side.

On the other hand, when the leading edge of the sheet 22A is fed to the driven conveying roller 27, the separating member 2
6 is pressed by the cam body 42 and is separated from the paper feed roller 23, and is in a biased release state. As a result, an open transport path 62 is formed between the paper feed roller 23 and the separating member transport surface 68. At this time, the separating member 26 descends due to the release of the bias, so that the stopper wall 67 is exposed from the separating member conveying surface 68 and is present in the open conveying path 62, as shown in FIG. Along with this, paper 2
After separating and feeding 2A, the uppermost sheet 22B among the sheets remaining in the conveying surface inlet 70 at the top of the inlet wall surface 69 tries to slide on the separating member 26, but the separating member conveying surface 68.
The stopper wall 6 that is exposed from and is present in the open transport path 62
It hits 7 and stops. Therefore, continuous feeding of the paper 22B is prevented. In particular, when the sheet 22B comes into contact with the sheet feed roller 23 and is about to be conveyed, there is a characteristic that the sheet 22B is conveyed in a tangential direction (obliquely lower left direction in the illustrated example) from the contact portion. Since the stopper wall 67 exists at the position, the entry stop function can be made more reliable with a simple structure. Further, in the present embodiment, the roller member 61
Unlike the case of the above-mentioned embodiment using the
Since the stopper wall 67 fixed integrally with the sheet 22B prevents continuous feeding of the sheet 22B, the continuous feeding can be prevented more reliably.

Further, in this embodiment, since the stopper wall 67 is formed integrally with the apparatus main body 2 and further with the paper guide member 66, the number of parts is increased even if the stopper wall 67 is provided. Not only that, but also the positional accuracy of the position where the paper 22B is stopped can be improved.

[0069]

According to the first aspect of the present invention, there is provided a compact and small number of parts of a sheet feeding and conveying apparatus in which a sheet base, a separating member, and a driven conveying roller are sequentially provided around one sheet feeding roller which is rotationally driven. According to the invention described above, there is no hindrance to the conveying path when the separating member is urged, and since the following sheet is provided in the opening conveying path when the urging of the separating member is released, the conveying regulation member is provided, After separating the uppermost paper fed from the paper tray by the separating member, the bias release means releases the pressure contact between the paper tray and the separating member with respect to the outer peripheral surface of the paper feed roller to form an open conveyance path. Even in the state, the succeeding paper sheet remaining on the separating member can be interfered with the transport restricting member and continuous feeding can be prevented.

According to the second aspect of the present invention, the feed restricting member of the sheet feeding / conveying device in the image forming apparatus according to the first aspect is rotatable on both sides of the separating member contact area on the shaft of the sheet feeding roller. Further, since the roller member is provided so as to be movable up and down, the roller member is displaced downward by its own weight when the biasing member is released from the bias, and a part of the roller member is positioned in the open conveyance path.
The effects of the invention described can be realized with a simple configuration.

According to the third aspect of the invention, the roller member of the sheet feeding and conveying device in the image forming apparatus according to the second aspect is
Since the weight is lowered to the position where it comes into contact with the separating member by its own weight, the open conveyance path when the biasing of the separating member is released is regulated like a wedge because the roller member descends to the position where it comes into contact with the separating member. As a result, it becomes difficult for the succeeding paper to pass under the roller member, and the effect of preventing continuous feeding can be further enhanced.

According to the fourth aspect of the invention, since the outer peripheral surface of the roller member of the sheet feeding and conveying device in the image forming apparatus according to the second aspect is processed to have an uneven shape, the succeeding sheet is not printed when the separating member is de-energized. When interfering with the roller member, the unevenness of the outer peripheral surface of the roller member can enhance the braking performance, and the effect of preventing continuous feeding can be further enhanced.

According to the fifth aspect of the present invention, in the sheet feeding / conveying device of the image forming apparatus according to the second aspect, a groove is formed on the separating member side so as to drop the roller member so as to block the open conveying path and displace it downward. Since the grooved portion is provided, the opening conveyance path when the biasing of the separating member is released is regulated to have the blocking wall because the roller member descends to the position where it falls into the groove portion of the separating member. The effect of preventing continuous feeding can be further enhanced.

According to the sixth aspect of the present invention, the conveyance regulating member of the sheet feeding and conveying device in the image forming apparatus according to the first aspect is formed so as to project from the apparatus main body side toward the conveying path around the sheet feeding roller. When the biasing member is biased, the stopper wall is hidden in the sorting member transporting surface, and when the biasing member is de-energized, the stopper wall has a height exposed from the sorting member transporting surface. It can be reliably obtained with an extremely simple configuration without increasing the number of points.

According to the seventh aspect of the invention, a sheet guide for forming a sheet guide path between the separating member and the driven roller on the stopper wall of the sheet feeding and conveying device in the image forming apparatus according to the sixth aspect. Since it is formed integrally with the member, the structure for preventing continuous feeding can be further simplified.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention, in which (a) is a schematic front view and (b) is a schematic longitudinal side view.

FIG. 2 is a schematic front view showing the entire compact printer.

FIG. 3 is a schematic front view showing a basic configuration of a sheet feeding and conveying device.

FIG. 4 is an exploded perspective view showing the vicinity of a paper tray and a separating member.

FIG. 5 is an exploded perspective view showing the vicinity of a driven conveyance roller.

FIG. 6 is a front view showing the assembled state.

FIG. 7 is a plan view showing the configuration of a power transmission system.

FIG. 8 is a schematic front view showing the basic configuration of a sheet feeding and conveying device including a power transmission system.

FIG. 9 is an exploded perspective view of constituent elements near a sheet feeding roller.

FIG. 10 is a front view showing the state of the cam and the like before the start of the paper feeding operation.

FIG. 11 is a front view showing the state of the cam and the like at the start of the paper feeding operation.

FIG. 12 is a front view showing the state of the cam and the like after the start of the paper feeding operation.

FIG. 13 shows a second embodiment of the present invention, (a) is a schematic front view, and (b) is a schematic vertical sectional side view.

FIG. 14 is a schematic front view showing a third embodiment of the present invention.

FIG. 15 is a perspective view of a separating member showing a fourth embodiment of the present invention.

FIG. 16 is a schematic vertical sectional side view thereof.

FIG. 17 is a schematic front view showing a part of the device in an enlarged manner.

FIG. 18 is an exploded perspective view showing constituent elements near a sheet feeding roller according to a fifth embodiment of the present invention.

FIG. 19 is an exploded perspective view showing the vicinity of a separating member.

FIG. 20 is a schematic front view showing a state when the separating member is urged and released.

FIG. 21 is a front view showing the outline of a general paper feeding / conveying device.

FIG. 22 is a schematic front view showing a proposal example of a paper feed / conveyance apparatus having a compact design.

FIG. 23 is a schematic front view for explaining the occurrence of continuous feeding when the biasing of the separating member is released.

[Explanation of symbols]

 2 Device Main Body 4 Image Forming Section 22 Paper 23 Paper Feeding Roller 24 Shaft 25 Paper Stand 26 Separation Member 27 Followed Conveying Roller 30 Paper Stand Energizing Means 34 Judging Member Energizing Means 36 Roller Energizing Means 41 Cams 42 Cams for Separation Members 43 Paper base cams 50, 51 Energizing release means 61 Roller member, transport regulating member 61a Part 62 Open transport route 63 Uneven surface 64 Groove-like portion 65 Paper guide route 66 Paper guide member 67 Stopper wall, transport regulating member 68 Determining member Transport surface

Claims (7)

[Claims] 1. A paper feed roller that is driven to be connected in synchronization with an image forming unit, a paper tray on which a plurality of sheets are stacked, and a paper on the paper tray is pressed against the outer peripheral surface of the paper feed roller. A sheet table urging means for urging the sheet table, a separating member located downstream of the sheet table in the sheet conveying direction and capable of coming into contact with and separating from the outer peripheral surface of the sheet feeding roller, and the separating member. A separating member urging means for urging the separating member so as to be pressed against the outer peripheral surface of the paper roller; and a rotatably contacting outer peripheral surface of the paper feeding roller located downstream of the separating member in the sheet conveying direction. A driven conveyance roller, a roller urging unit that urges the driven conveyance roller so that the driven conveyance roller comes into pressure contact with the outer peripheral surface of the paper feed roller, and a driven system different from the drive system of the paper feed roller. Controlled by the paper feed roller A paper table cam part that rotates in the same direction and moves the paper table in a direction approaching the paper feed roller by the urging force of the paper table urging means by the rotation, and by the rotation, the separating member. A cam having a separating member cam portion that is moved by the urging force of the member urging means toward the paper feeding roller, and after the cam rotates a predetermined angle, the paper table and the separating member are moved. An urging releasing means for releasing pressure contact with the outer peripheral surface of the sheet feeding roller, and a conveying path when the separating member is energized are not hindered, and are located in an open conveying path when the separating member is urging released. A sheet feeding / conveying device in an image forming apparatus, comprising: a conveyance regulating member that interferes with sheets. 2. The transport restricting member is a roller member provided on the shaft of the paper feed roller so as to be rotatable and vertically movable on both sides of a separating member contact area, and is self-weighted when the biasing of the separating member is released. 2. The sheet feeding / conveying apparatus in the image forming apparatus according to claim 1, wherein the sheet feeding / conveying apparatus is displaced downward by and is partially positioned in the open conveying path. 3. The roller member is displaced downward by its own weight to a position where the roller member comes into contact with the separating member.
A sheet feeding / conveying device in the image forming apparatus. 4. The paper feeding / conveying device in an image forming apparatus according to claim 2, wherein the roller member has an outer peripheral surface processed into an uneven shape. 5. The sheet feeding / conveying device in the image forming apparatus according to claim 2, wherein the roller member has a groove-like portion on the side of the separating member, the groove portion being depressed so as to block the open conveying path and move downward. 6. The conveyance restricting member is formed so as to project from the apparatus main body side toward the conveyance path around the paper feed roller, and is hidden in the separating member conveying surface when the separating member is energized, and when the separating member is deenergized. 2. The sheet feeding / conveying device in the image forming apparatus according to claim 1, wherein the stopper wall has a height exposed from the separating member conveying surface. 7. The image forming apparatus according to claim 6, wherein the stopper wall is formed integrally with a paper guide member for forming a paper guide path between the separating member and the driven roller. Paper feeding and conveying device.