JPH0249244Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a sheet member conveying device that can be conveniently applied to an electrostatic copying machine, etc., and more specifically, a feeding roller assembly for feeding a sheet member, and the feeding roller assembly. The present invention relates to a sheet member conveying apparatus including a temporary blocking means disposed downstream of the assembly for temporarily blocking the advancement of the sheet member fed by the feed roller assembly.

As is well known, electrostatic copying machines and the like are provided with a sheet member conveyance system for conveying a sheet member such as copy paper, which may be ordinary paper, through a required path. Such a sheet member conveying system includes a sheet member sending means for manually or automatically sending out a sheet member, and a sheet member conveying device for conveying the sheet member sent out from the sheet member sending means. There is. Sheet member transport systems generally include a feed roller assembly and a temporary blocking means disposed downstream of the feed roller assembly. The above feed roller assembly is
It has a driven roller that is continuously driven to rotate and a driven roller that cooperates with the driven roller. The temporary blocking means generally comprises a selectively actuated roller assembly having a selectively rotationally driven driven roller and a cooperating driven roller.

In the sheet member conveying device as described above,
The sheet member manually or automatically fed out from the sheet member feeding means is nipped by a driven roller and a driven roller that are continuously rotationally driven in the feed roller assembly, and the sheet member is temporarily stopped. send towards. The leading edge of the sheet member is then brought into contact with the nip between an undriven driven roller and a driven roller of a selectively actuated roller assembly forming a temporary blocking means. Advancement of the sheet member is thus prevented and also
When the sheet member is in an inclined state, that is, its leading edge is not substantially perpendicular to the conveying direction but is inclined, the inclined state of the sheet member is corrected. Thereafter, the driven rollers of the selectively actuated roller assembly are synchronized as desired, such as with the scanning exposure of the document to be reproduced or the rotation of a rotating drum on the surface of which a toner image corresponding to the document to be reproduced is formed. The rotational drive of the sheet member is started, and the conveyance of the sheet member, which has been temporarily stopped, is restarted. Accordingly, the temporary blocking means, which is comprised of a selectively actuated roller assembly, performs the function of straightening the sheet member and the function of synchronously transporting the sheet member.

However, the conventional sheet member conveying device as described above has the following problems or drawbacks that must be solved. While advancement of the sheet member is prevented by the temporary blocking means, a driven roller in the feed roller assembly continues to rotate;
Therefore, a slip condition is continuously maintained between the driven roller and the sheet member, and this tends to cause one side of the sheet member to become contaminated. Such contamination on one side of the sheet member is not so much of a problem when the duplicate image is formed only on the other side of the sheet member, but becomes a serious problem when the duplicate image is formed on both sides of the sheet member. . Furthermore,
In particular, when the sheet member has low stiffness (so-called weak material), the slip state described above is not generated between the driven roller in the feeding roller assembly and the sheet member, and the temporary blocking means The feed roller assembly continues to feed the sheet member even though the advance of the sheet member is blocked by the feed roller assembly, which causes the temporary blocking means to disengage between the feed roller assembly and the temporary blocking means. In many cases, wrinkles are formed in the sheet member and jamming occurs.

In order to solve the problems as described above, the rotational drive of the driven roller in the feed roller assembly can be selectively controlled, and the advance of the sheet member is prevented by a temporary blocking means. It is intended to immediately stop the rotational drive of the driven roller in the feed roller assembly. However, in order to do this, it is necessary to dispose a drive coupling control clutch means between the drive source and the driven roller of the feed roller assembly, and to provide a control means for such clutch means. This significantly impedes cost reduction and miniaturization of electrostatic copying machines and the like.

The present invention has been developed in view of the above facts, and its main purpose is to provide a tilt correction function and a tilt correction function by a temporary blocking means without causing any significant harm to the cost reduction and miniaturization of electrostatic copying machines, etc. It is an object of the present invention to provide a new and improved sheet member conveying device that can avoid or considerably reduce the above-mentioned contamination of one side of a sheet member without adversely affecting the synchronous conveyance function.

According to the present invention, there is provided a feed roller assembly for feeding a sheet member, and a feed roller assembly disposed downstream of the feed roller assembly for feeding the sheet member by the feed roller assembly. a temporary blocking means for temporarily blocking forward movement; the feed roller assembly includes a driven shaft rotatably driven by a drive source; and a driven shaft disposed at a distance from the driven shaft. a driven shaft, a plurality of driven rollers attached to the driven shaft, and at least one driven roller attached to the driven shaft, and a sheet member is provided between the driven roller and the driven roller. In a nipping and feeding sheet material transport device; the driven rollers include at least one actively driven roller and at least one passively driven roller; The passively driven roller is mounted on the driven shaft so as to be actively rotated as the shaft rotates, and the passively driven roller has an inner diameter larger than an outer diameter of the driven shaft, and has an inner diameter larger than an outer diameter of the driven shaft. is loosely fitted to the feed roller assembly, and when advancement of a sheet member being fed by the feed roller assembly is blocked by the temporary blocking means, an additional force is applied from the sheet member to the passively driven roller. There is provided a sheet member conveying device characterized in that the rotation of the passively driven roller is stopped by the resistance caused by the driven shaft even though the driven shaft is rotationally driven.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred specific examples of a sheet member conveying device constructed according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 illustrates an example of an electrostatic copying machine to which a specific example of a sheet member conveying device constructed according to the present invention is applied. The illustrated electrostatic copying machine has a housing 2 having a substantially rectangular parallelepiped shape. A document placing means 4 is mounted on the housing 2 so as to be movable in the left and right directions in FIG. The document placement means 4 has a support frame 6 and a transparent plate 8 attached to the support frame 6.

A rotary drum 10 having a photoreceptor on its circumferential surface is rotatably disposed approximately in the center of the housing 2 . Around the rotating drum 10, which is rotated in the direction shown by the arrow 12, there are, in order in the direction of rotation, a charging corona discharger 14, an optical system 16, a developing device 18, a transfer corona discharger 20, and a peeling corona discharger. A cleaning device 26 having a corona discharger 22, a cleaning blade 24, and a static elimination lamp 28
is installed. Further, a document irradiation lamp 30 is provided in association with the optical system 16. The document irradiation lamp 30 irradiates the document to be copied (not shown) placed on the transparent plate 8 of the document placement means 4 through the opening 34 formed in the upper plate 32 of the housing 2. . A large number of elongated optical elements extending in the vertical direction (for example, rod-shaped lenses sold by Nippon Sheet Glass Co., Ltd. under the trade name "Self-Oc Micro Lens") are arranged in the front-back direction (direction perpendicular to the plane of the paper in Figure 1). An optical system 16 configured by the above-mentioned system projects reflected light from the document onto the circumferential surface of the rotating drum 10, as shown by the arrow in FIG.

Approximately in the lower half of the housing 2, a sheet member conveyance system, generally designated 36, is disposed. At one end of the sheet member conveyance system 36 (the right end in FIG. 1), a cassette-type automatic sheet member delivery means 38 is provided for automatically delivering sheet members.
and a manual sheet member delivery means 40 disposed above it for manually delivering the sheet member. The automatic sheet member feeding means 38
consists of a combination of a cassette receiver 44 provided with a delivery roller 42 and a copy paper cassette 48 that is mounted on the cassette receiver 44 through an opening 46 formed in the right end wall of the housing 2. By the action of a selectively rotationally driven delivery roller 42, sheet members are delivered sheet by sheet from a layer 50 of sheet materials contained in a copy paper cassette 48. The sheet member may be ordinary paper. The manual sheet member feeding means 40 includes a housing 2
a manual feed stand 54 extending outward from an opening 52 formed in the right end wall of the frame, and a pair of guide plates disposed within the housing 2 in association with the manual feed stand 54, namely a lower guide plate 56 and an upper guide plate 58. It consists of When manually feeding a sheet member, such as ordinary paper, the sheet member is positioned on the manual feed table 54 and advanced through the opening 52 and between the pair of guide plates 56 and 58.

On the downstream side of the pair of guide plates 56 and 58, a specific example of a sheet member conveying device improved according to the present invention is disposed. The illustrated sheet material transport system, designated generally by the numeral 60, includes a feed roller assembly 6
2 and a temporary blocking means 64 disposed downstream of the feed roller assembly 62. The feed roller assembly 62 includes a driven roller 70 that is continuously driven to rotate and a driven roller 72 that cooperates therewith. Further, the temporary blocking means 64 includes a driven roller 74 that is selectively driven to rotate, and a driven roller 76 that cooperates with the driven roller 74. In the illustrated embodiment, the sheet material transport apparatus further includes a pair of guide plates disposed between the feed roller assembly 62 and the temporary blocking means 64, namely a lower guide plate 66 and an upper guide plate 68. Contains.
Such a sheet member conveying device 60 will be described in more detail later.

A pair of guide plates is arranged downstream of the temporary blocking means 64, namely a lower guide plate 78 and an upper guide plate 80. In FIG. 1, on the left side of the rotating drum 10, there is a fixing device 86 having a conveyor belt mechanism 82, a guide plate 84, a driven heating roller 88, and a driven roller 90, and a driven roller 9 that is continuously driven to rotate.
4 and a driven roller 96, and a tray 100 extending outwardly through an opening 98 formed in the left end wall of the housing 2.

In the copier as described above, while the rotating drum 10 is rotated in the direction indicated by the arrow 12, the charging corona discharger 14 substantially uniformly charges the photoreceptor to a particular polarity and then charges the photoreceptor through the optical system 16. The image of the original is projected onto the photoreceptor (at this time,
The document placement means 4 moves from the scanning exposure start position indicated by the two-dot chain line 4A in FIG. 1 to the right in FIG. 1), thus forming an electrostatic latent image corresponding to the document on the photoreceptor. Ru. A developer device 18 then applies toner particles to the electrostatic latent image on the photoreceptor to develop the electrostatic latent image into a toner image. On the other hand, a sheet member that is automatically fed out from the automatic sheet member feeding means 38 or a sheet member that is manually fed out from the manual sheet member feeding means 40 and fed by the action of the feeding roller assembly 62 is , its leading edge is brought into contact with the nip position between the driven roller 74 and the driven roller 76 which are in a non-driven state. Thus, if the advance of the sheet member is prevented and also if the sheet member is in a tilted condition, i.e. its leading edge is not substantially perpendicular to the direction of conveyance but is tilted, such tilted condition of the sheet member is corrected. Next, in synchronization with the rotation of the rotary drum 10 as required, the rotation of the driven roller 74 which has been in a non-driving state is started, and the conveyance of the sheet member, which had been temporarily stopped, is resumed.
A sheet member is advanced through the pair of guide plates 78 and 80 into contact with the surface of the photoreceptor on the rotating drum 10. Then, the toner image on the photoreceptor is transferred to the sheet member by the action of the transfer corona discharger 20, and then the peeling corona discharger 2
The sheet member is peeled off from the surface of the photoreceptor by the action of step 2. The sheet member onto which the toner image has been transferred is conveyed by the action of the conveyor belt mechanism 82 and sent to a fixing device 86 . The sheet member on which the toner image has been fixed in the fixing device 86 is discharged to the receiving tray 100 by the action of the discharge roller assembly 92 . Meanwhile, the rotating drum 10 continues to rotate,
The action of cleaning device 26 removes residual toner particles from the photoreceptor, and the action of discharge lamp 28 then dissipates any residual charge on the photoreceptor.

Therefore, the structure and operation of the illustrated copying machine other than the sheet member conveying device 60 are already known, and the illustrated copying machine is adapted to the sheet member conveying device constructed according to the present invention. This is only one example, and therefore, detailed explanations of structures and operations other than the sheet member conveying device 60 will be omitted in this specification.

Next, referring to FIGS. 2 to 4, the illustrated sheet member conveying device constructed according to the present invention will be described.
includes a feed roller assembly 62, a temporary blocking means 64, and a pair of guide plates 64 and 66 disposed therebetween, as described above.

With reference to FIGS. 2 and 3, temporary blocking means 6
4, in the illustrated example, a pair of supporting side walls 102 and 104 are provided within the housing 2 at intervals in the front-rear direction (direction perpendicular to the plane of paper in FIG. 1). Temporary blocking means 64 includes a pair of supporting side walls 102 and 10.
The drive shaft 106 includes a driven shaft 106 and a driven shaft 108 extending between the two shafts. The driven shaft 106 has a bearing member 110
and 112 to the supporting side walls 102 and 104 and extend substantially horizontally as shown in FIG. The driven shaft 106 is provided with the driven rollers 74 at intervals in the axial direction.
Two are installed. This driven roller 74 can be formed from a suitable metal material or synthetic resin material. One end of the driven shaft 106 projects beyond the support side wall 104, and a sprocket wheel 114 is rotatably mounted on the one end. Spring clutch 1 known per se for selectively connecting
16 is installed. Sprocket wheel 1
14 is drivingly connected to a drive source (not shown), which may be a drive motor, and is caused to rotate continuously while the drive source is energized. When the spring clutch 116 is actuated, the sprocket wheel 114 and the driven shaft 106 are drivingly connected, thus causing the driven shaft 106 and the driven roller 74 attached thereto to move in the direction indicated by the arrow 120 (second
It is rotated in the direction shown in the figure. When the spring clutch 116 is deactivated, the connection between the sprocket wheel 114 and the driven shaft 106 is released, and thus the driven shaft 106 and the driven roller 74 attached thereto are released.
rotational drive is stopped. As shown in FIGS. 2 and 3, bearing members 122 and 124 are attached to both ends of the driven shaft 108 located above the driven shaft 106 described above. The supporting side wall 102
and 104 are formed with elongated holes 126 and 128 extending in the direction of driven shaft 106, within which bearing members 122 and 124 are positioned. Thus, as can be readily seen in FIG. 3, driven shaft 108 is rotatably mounted to supporting side walls 102 and 104 for rotation and movement toward and away from driven shaft 106. Such support shaft 108
The two driven rollers 76 described above are attached to correspond to the two driven rollers 74 described above. The driven roller 76 can be formed from a synthetic resin material or a metal material. Further, appropriate spring members 130 and 132 are provided in association with the bearing members 122 and 124 mounted on the driven shaft 108. These spring members 130 and 132 elastically bias the driven shaft 108 toward the driven shaft 106, thus forcing the driven roller 76 toward the driven roller 7.
Press down to 4.

The illustrated feed roller assembly 62 will now be described with reference to FIG. 4 in conjunction with FIG. The feed roller assembly 62 includes a driven shaft 134 and a driven shaft 1 extending between the pair of supporting side walls 102 and 104.
Contains 36. The driven shaft 134 is connected to the supporting side walls 102 and 1 through bearing members 138 and 140.
04, and extends substantially horizontally as shown in FIG. One end of this driven shaft 134 protrudes beyond the support side wall 104, and a gear 142 is fixed to this one end. gear 1
42 is the drive source (not shown), which may be a drive motor.
The drive is connected to the Therefore, while the drive source is energized, the gear 142 and the driven shaft 134 to which it is fixed are continuously rotated in the direction indicated by the arrow 144 (FIG. 2).

The driven roller 70 described above is connected to the driven shaft 134.
is installed on. Importantly, the driven rollers 70 include at least one actively driven roller and at least one passively driven roller. In the specific example shown, as shown in FIG.
a and four passively driven rollers 70b. Actively driven roller 70a and passively driven roller 70b are preferably formed from a material having a relatively low coefficient of friction, such as a synthetic resin material. In the specific example, the driven shaft 134 has four rings 14 arranged at predetermined intervals in the axial direction.
6, 148, 150 and 152 are fixed, one actively driven roller 70a and two passively driven rollers 70b are disposed between rings 146 and 148, and between rings 150 and 152 there is one actively driven roller 70a and two passively driven rollers 70b. Also provided are one actively driven roller 70a and two passively driven rollers 70b. Each of the passive driven rollers 70b is connected to the driven shaft 13
It is important that the inner diameter _D2 is larger than the outer diameter d of the drive shaft 134, and the drive shaft 134 is rotatably mounted on the driven shaft 134. On the other hand, each of the actively driven rollers 70a is configured to actively rotate the driven shaft 134 as the driven shaft 134 rotates.
34 is important. 5-7 in conjunction with FIG. 4, in the illustrated embodiment, the outer diameter of positively driven roller 70a is the outer diameter of passively driven roller 70b, as shown in FIG. However, as will be understood from the description below, the inner diameter D ₁ (FIG. 5) of the positively driven roller 70a is larger than the outer diameter d of the driven shaft 134 (D ₁ >d ) and is made somewhat larger than the inner and outer sides D ₂ (FIGS. 5 and 6) of the passively driven roller 70b (D ₁ >D ₂ ). Therefore, the radial thickness of the actively driven roller 70a is made somewhat smaller than the radial thickness of the passively driven roller 70b. Driven shaft 13
4 and the actively driven roller 70a are provided with cooperating means that cooperate with each other to actively transmit the rotation of the driven shaft 134 to the actively driven roller 70a. As shown in FIGS. 4 to 6, the driven shaft 1
Two pins 154 extending diametrically through the driven shaft 134 are fixed to each of the portions of the drive shaft 134 to which the actively driven rollers 70a are mounted. Both ends of the pin 154 are connected to the driven shaft 134.
Thus, on the outer surface of the driven shaft 134, there are two sets of two diametrically opposed protrusions 156 (i.e., both ends 156 of the pin 154). Correspondingly, the inner surface of the actively driven roller 70a is formed with two diametrically opposed recesses 158 that extend continuously in the axial direction. As shown in FIGS. 5 to 7, it is advantageous for both the tip end surface of the convex portion 156 and the bottom surface of the recessed portion 158 to have a semicircular cross-sectional shape. Each of the protrusions 156 is positioned within a respective recess 158, thus causing driven shaft 134 to rotate in the direction indicated by arrow 144 in FIGS. 5 and 6, as will be readily understood. and,
Due to the cooperation of the convex portion 156 and the concave portion 158, the positively driven roller 70a is also
It is actively rotated in the direction shown by arrow 144 in the figure. Continuing the explanation with reference to FIGS. 5 and 6, in the illustrated example, the length L between the bottom surfaces of the two diametrically opposing recesses 158 and the length L between the two diametrically opposing bottom surfaces of the recesses 158 are The difference L-l between the length l between the protrusions 156 is the inner diameter of the actively driven roller 70a.
The difference between D ₁ and the outer diameter d of the driven shaft 134 is made slightly smaller than the difference D ₁ −d (L−l<D ₁ −
d, so L-l/2< _D1 -d/2). Difference W between the circumferential width W of the concave portion 158 and the circumferential width W of the convex portion 156
-w is slightly larger than the above difference L-l (W-w>
L−l, therefore W−w/2>L−l/2), and is substantially the same as or slightly smaller than the above difference D ₂ −d (W−w≦
D ₂ -d, therefore W-w/2≦D ₂ -d/2) (i.e., D ₂ -d≧W-w>L-l, therefore D ₂ -d/2≧W -w/2>L-l/2). As such, it will be readily appreciated that the positively driven roller 70a is biased downwardly due to its own weight. Accordingly, as will be readily understood, driven shaft 134 and positively driven roller 70
When a is in the angular position shown in FIG. 5, the positively driven roller 70a is biased downwardly due to its own weight, so that it is in the position shown in FIG. The bottom surface of the roller 70a is in contact with the tip surface of the convex portion 156 located above, and the upper end of the actively driven roller 70a is connected to the driven shaft 134.
at a height h ₁ from the central axis of. Further, the driven shaft 134 and the actively driven roller 70a are moved in the direction shown by the arrow 144 from the angular position shown in FIG.
When rotated 90 degrees, the actively driven roller 70a is similarly biased downward by its own weight, resulting in the state shown in FIG. roller 70
The upper end of a is at a height from the center axis of the driven shaft 134.
It will be at the level of _h2 . As mentioned above, the difference W−w is the difference L
Since the height h 1 is larger than the height h ₂ (h 1 >h 2 ), the height h 1 is larger than the height h ₂ (h ₁ >h ₂ ). Therefore, while the driven shaft 134 and the actively driven roller 70a rotate 90 degrees from the angular position shown in FIG. 6 to the angular position shown in FIG.
As will be readily understood, actively driven roller 70
a is gradually displaced downward with respect to the driven shaft 134,
Driven shaft 13 at the upper end of actively driven roller 70a
4 from the central axis is reduced from h ₁ to h ₂ .
The driven shaft 134 and actively driven roller 70a are then rotated an additional 90 degrees from the angular position shown in FIG. While
As will be readily understood, actively driven roller 70
a is gradually displaced upward with respect to the driven shaft 134,
Driven shaft 1 at the upper end of actively driven roller 70a
The height of 34 from the central axis increases from h ₂ to h ₁ . That is, in the illustrated example, the driven shaft 1
34 and the actively driven roller 70a rotate one rotation (360 degrees), the actively driven roller 70a alternately moves up and down two times with respect to the driven shaft 134.
be made to carry out the In the specific example, two pins 15 are provided corresponding to each actively driven roller 70a.
Although four pins 154 are provided, one pin 154 may be used if the actively driven roller 70a can be actively rotated as required. In addition, in the specific example, each time the driven shaft 134 and the actively driven roller 70a rotate, the actively driven roller 70a rotates.
0a is configured to move up and down twice with respect to the driven shaft 134, but such actively driven roller 70a
It is important that the vertical movement is performed at least once during each revolution. In the specific example, the actively driven roller 70a is in the most elevated state relative to the driven shaft 134, ie, in the state shown in FIGS. 4 and 6.
Actively driven roller 70 in the condition shown
The height _h1 of the upper end of the passive driven roller 70b from the central axis of the driven shaft 134 is the height h of the upper end of the passive driven roller 70b from the central axis of the driven shaft 134 (FIG. 4).
(h ₁ =h). As will be readily understood, passively driven roller 70b
is not substantially displaced upwardly or downwardly with respect to the driven shaft 134, so the heights h are substantially the same.

As can be seen from FIG. 4, the movement of the positively driven roller 70a and the passively driven roller 70b in the axial direction of the driven shaft 134 is caused by the ring 1
46, 148, 150, and 152. These actively driven rollers 70a
and the passively driven roller 70b are arranged corresponding to the JIS standard paper size (for example, B4, A4, B5, etc.).

Continuing the explanation with reference to Figures 2 and 4,
Bearing members 160 and 162 are attached to both ends of the driven shaft 136 located above the driven shaft 134. The supporting side walls 102 and 104 include:
As shown in FIG. 4, elongated holes 164 and 166 are formed that extend in the direction toward the driven shaft 134, and the bearing members 160 and 162 are positioned within the holes 164 and 166. Thus, the driven shaft 136 is rotatably connected to the driven shaft 1.
It is mounted to supporting side walls 102 and 104 so as to be movable toward and away from 34. The two driven rollers 72 described above are fixed to the driven shaft 136. As shown in FIG. 4, one driven roller 72 is connected to the ring 146.
and three driven rollers 70 located between 148 and 148.
(one actively driven roller 70a and two passively driven rollers 70b), and the other driven rollers 72 are positioned corresponding to the rings 150 and 152.
It is located corresponding to three driven rollers 70 (one actively driven roller 70a and two passively driven rollers 70b) located therebetween. This driven roller 72 can be formed from a metal material or a synthetic resin material. The driven roller 72 is pressed against the driven roller 70 by its own weight and the weight of the driven shaft 136, as is easily understood.
If desired, the driven shaft 13 can be secured by a suitable spring member.
6 may be elastically biased toward the driven shaft 134, thus forcing the driven roller 72 against the driven roller 70.

Next, with reference to FIGS. 2 to 7, particularly FIG. 2, the effects of the sheet member conveying device 60 as described above will be described. The leading edge of the sheet member s delivered from the manual sheet member delivery means 40 is driven by driven rollers 70 (i.e., actively driven roller 70a and passively driven roller 70b) in the feed roller assembly 62. When the sheet member s reaches the nip position with the roller 72, the driven roller 70 and the driven roller 72 nip the sheet member s and feed it. At this time, the passive driven roller 72 is moved by the weight of itself and the driven shaft 136.
0b, the inner circumferential surface of the passive driven roller 70b is pressed against the outer circumferential surface of the driven shaft 134 at a portion indicated by the symbol A in FIG.
A required frictional force FA is generated between the inner circumferential surface of the passive driven roller 70b and the outer circumferential surface of the driven shaft 134. Therefore, the rotation of the driven shaft 134, which is continuously rotationally driven, is transmitted to the actively driven roller 70 through the convex portion 156 and the concave portion 158.
a, and is also transmitted to the passive driven roller 70b by the action of the frictional force FA,
Passively driven roller 70b is rotated in the direction indicated by arrow 144 along with actively driven roller 70a. Thus, sheet member s is moved in the direction of arrow 16 primarily by the action of passively driven roller 70b.
8, and the driven roller 72 is rotated in the direction shown by arrow 170. As described above, the actively driven roller 70a alternately ascends and descends once every revolution, and when it has risen the most (i.e., in the state shown in FIGS. 4 and 6), it is actively driven. The height h ₁ of the upper end of the target driven roller 70a is substantially the same as the height h of the upper end of the passive driven roller 70b. Therefore, when the actively driven roller 70a is raised the most (2 times during one rotation)
2) temporarily acts on the sheet member s.

The sheet member s fed by the feed roller assembly 62 is guided through the guide plates 66 and 68 to the nip position of the non-driven driven roller 74 and the driven roller 76 in the temporary blocking means 64. It will be destroyed. When the leading edge of the sheet member s is brought into contact with the nip position between the driven roller 74 and the driven roller 76 which are in the non-driven state, the sheet member s
is in an inclined state, i.e. its leading edge is not substantially perpendicular to the conveying direction 156 but is inclined, such inclination is corrected and the sheet member s
progress is blocked. Thus, the sheet member s
has a relatively large stiffness (i.e.,
(so-called relatively strong-willed), the second
As shown by the solid line in the figure, the sheet member s is substantially not curved due to its relatively large stiffness, and its entirety is stopped. On the other hand, if the sheet member s has a relatively small stiffness (that is, is relatively stiff), even after the forward movement of the sheet member s is prevented by the temporary blocking means 64. , the feeding of the sheet member s due to the action of the feeding roller assembly 62 continues for a short time, which causes the temporary blocking means 64 and the feeding roller assembly to disintegrate, as shown by the two-dot chain line in FIG. 62, the sheet member s is curved. However, it is desirable that the pair of guide plates 66 and 68 described above be arranged sufficiently close together, so that when the sheet member s is curved somewhat, the sheet member s will be placed close enough to the lower guide plate. 66 as well as the upper guide plate 68, thereby suppressing further curvature of the sheet member s and also increasing the apparent stiffness of the sheet member s. Thus, the sheet member s
is stopped in its entirety without the formation of undesirable wrinkles.

When the entire sheet member s is stopped as described above, the rotation of the driven roller 72 in the roller assembly 62 is inevitably stopped. Also, the sheet member s is attached to the feed roller assembly 62
Therefore, a frictional force FB is generated between the lower surface of the sheet member s and the outer peripheral surface of the passively driven roller 70b at a portion indicated by the symbol B in FIG. generated. Thus,
This frictional force FB is caused by the passive driven roller 70
The frictional force FA generated between the inner circumferential surface of b and the outer circumferential surface of the driven shaft 134 is greater than the above-mentioned frictional force FA. Thus, although the driven shaft 134 is continuously driven to rotate, the rotation of the passive driven roller 70b is stopped. Therefore, an undesirable phenomenon that has occurred in conventional feed roller assemblies, namely, the passively driven roller 70b continues to rotate with respect to the stationary sheet member, and a slip condition is continuously maintained between the two. The phenomenon that the lower surface of the sheet member is contaminated by this,
will definitely be avoided.

On the other hand, since the rotation of the driven shaft 134 is positively transmitted to the actively driven roller 70a by the cooperation of the convex portion 156 and the recessed portion 158, the actively driven roller 70a continues to rotate. However, as described above, the actively driven roller 70a only temporarily acts on the sheet member s when it is raised the most (twice during one rotation), and therefore actively acts on the sheet member s that is stationary. There is only a temporary slip condition between the driven roller 70a and the active driven roller 70a twice during one rotation of the actively driven roller 70a, so that the actively driven roller 70a continues to rotate. There is very little, if any, contamination of the lower surface of the sheet member s by this.

On the other hand, in order to avoid staining the lower surface of the sheet member s with sufficient certainty, the configuration of the actively driven roller 70a is made to be the same as that of the actively driven roller 70b, in other words the driven roller 70
It is conceivable to make all of them passively driven rollers. However, according to the experience of the present inventors, it has been found that if all of the driven rollers 70 are made to be passive driven rollers, the following problems tend to occur. That is, the effect of bringing the leading edge of the sheet member s into contact with the nip position between the driven roller 74 and the driven roller 76 that are not driven becomes insufficient, and as a result, the sheet member s is tilted. (i.e., when the leading edge of the sheet member s is not substantially perpendicular to the conveyance direction 156 but is inclined), such inclination may not be properly corrected or the driven roller may 74
and the arrow 1 of the sheet member s by the driven roller 76
There is a tendency for a slight delay to occur in the conveyance in the direction indicated by 68 (such delay causes an error in the period between the rotation of the rotary drum 10 and the conveyance of the sheet member s). However, if the driven rollers 70 of the feed roller assembly 62 include an actively driven roller 70a, even after the passively driven roller 70b has stopped rotating, the actively driven roller 70a remains active. It continues to rotate, intermittently (2 times during one rotation)
(times)) on the sheet member s, and thus the above-mentioned disadvantages are fully avoided.

After the sheet member s has been stopped in the manner described above, the clutch 116 in the temporary blocking means 64 is actuated in predetermined synchronization with the rotation of the rotating drum 10 (FIG. 1), and the driven roller 74 begins to be rotationally driven in the direction indicated by arrow 120. Thus, conveyance of the sheet member s is resumed, the sheet member s is conveyed in the direction shown by arrow 156, and the driven roller 76 is rotated in the direction shown by arrow 160. As the sheet member s begins to be transported in the direction indicated by arrow 156, the passively driven roller 70b and driven roller 72 of the feed roller assembly 62 move in the direction indicated by arrow 14, as will be readily appreciated.
6 and 158.

In the sheet member conveyance device 60 described above,
The temporary blocking means 64 is composed of a driven roller 74 and a driven roller 76 that are selectively rotationally driven, but instead of this, the temporary blocking means 64 protrudes into the conveying path of the sheet member to prevent the sheet member s from advancing. It is also possible to include an appropriate stop member or the like that can be selectively positioned at an active position where the sheet member s is moved forward and a non-active position where the sheet member s is allowed to move forward away from the transport path of the sheet member.

FIG. 8 illustrates a modification of the feed roller assembly 62 of the sheet member transport device 60. In the modification shown in FIG. 8, six actively driven rollers 70a and six passively driven rollers 70b are disposed on the driven shaft 134, as shown in FIG. More specifically, rings 146 and 148
In between, three actively driven rollers 70a having a relatively small axial width and three passively driven rollers 70b having a relatively large axial width are alternately installed. Similarly, rings 150 and 15
Three actively driven rollers 70a having a relatively small width in the axial direction and three passively driven rollers 70b having a relatively large width in the axial direction are alternately installed between the two rollers. The actively driven roller 70
The structure and operation of the passively driven roller 70a and the passively driven roller 70b is substantially the same as that shown in FIGS. 4-7.

In such a variation, effects similar to those shown in FIGS. 1-7 are achieved, and in addition, due to the relatively small axial width of the actively driven roller 70a, the sheet Contamination of members can be suppressed more effectively.

Although specific examples of the sheet member conveying device constructed according to the present invention have been described above, the present invention is not limited to such specific examples, and various modifications and modifications can be made without departing from the scope of the present invention. is possible.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view showing an electrostatic copying apparatus to which a specific example of a sheet member conveying apparatus constructed according to the present invention is applied. FIG. 2 is a sectional view showing the sheet member conveying device in the copying machine of FIG. 1. FIG. 3 is a sectional view showing temporary blocking means in the sheet member conveying device of FIG. 2; FIG. 4 is a sectional view showing the feed roller assembly in the sheet member conveying device of FIG. 2. 5 is a diagram for explaining the relationship between the driven shaft and the positively driven roller in the feed roller assembly of FIG. 4, and FIG. 6 is a diagram for explaining the relationship between the driven shaft and the actively driven roller in the feed roller assembly of FIG. FIG. 3 is a cross-sectional view showing a state when the target driven roller is displaced most upwardly. Figure 7 shows
FIG. 5 is a cross-sectional view of the feed roller assembly of FIG. 4 when the actively driven roller is displaced most downward; FIG. 8 is a partial front view showing a modification of the feed roller assembly. 60... Sheet member conveyance device, 62... Feeding roller assembly, 64... Temporary blocking means, 66 and 68...
Guide plate, 70... Driven roller, 70a... Actively driven roller, 70b... Passive driven roller, 72
... Driven roller, 134 ... Driven shaft, 136 ... Driven shaft, 154 ... Pin, 156 ... Convex part, 158 ... Concave part, s ... Sheet member.

Claims (1)

[Claims for Utility Model Registration] 1. A feed roller assembly for feeding a sheet member, and a feed roller assembly disposed downstream of the feed roller assembly,
temporary blocking means for temporarily blocking the advance of the sheet member fed by the feed roller assembly, the feed roller assembly being driven to rotate by a drive source; A shaft, a driven shaft spaced apart from the driven shaft, a plurality of driven rollers mounted on the driven shaft, and at least one driven roller mounted on the driven shaft. , a sheet material conveying device for nipping and feeding a sheet material between the driven roller and the driven roller; the driven roller having at least one actively driven roller and at least one passively driven roller; a drive roller, the actively driven roller is mounted on the driven shaft so as to be actively rotated as the driven shaft rotates, and the passively driven roller is mounted to the driven shaft so as to be actively rotated as the driven shaft rotates. has an inner diameter larger than the outer diameter of the drive shaft and is loosely fitted to the driven shaft,
When advancement of a sheet member being fed by the feed roller assembly is blocked by the temporary blocking means, the resistance applied from the sheet member to the passively driven roller causes the sheet member to A sheet member conveying device characterized in that the rotation of the passively driven roller is stopped even though the driven shaft is rotationally driven. 2. The positively driven roller is displaced upwardly and downwardly with respect to the driven shaft during one rotation, and when the positively driven roller is displaced most upwardly, the upper end of the positively driven roller The sheet member conveying device according to claim 1, wherein the upper end of the passively driven roller and the upper end of the passively driven roller are substantially at the same level. 3. The actively driven roller has an inner diameter larger than the inner diameter of the passively driven roller, and the driven shaft and the actively driven roller cooperate with each other to control the rotation of the driven shaft. cooperating means are provided for transmitting the force to the positively driven roller and causing the positively driven roller to be displaced upwardly and downwardly with respect to the driven axis by the weight of the positively driven roller itself. A sheet member conveying device according to claim 2, which is a utility model. 4. The cooperative means is constituted by at least one protrusion provided on the outer surface of the driven shaft and at least one recess provided on the inner surface of the positively driven roller. A sheet member conveying device according to claim 3. 5. The outer surface of the driven shaft is provided with two diametrically opposed convex portions, and the inner surface of the actively driven roller is provided with two diametrically opposed recessed portions. A sheet member conveying device according to claim 4 of the utility model registration claim. 6. The sheet member conveying device according to any one of claims 1 to 5, wherein the driven roller is made of a material having a relatively small coefficient of friction. 7. The sheet member conveying device according to claim 6, wherein the driven roller is made of a synthetic resin material.