JP7206636B2 - Automatic transport device and image forming device - Google Patents

Description

The present invention relates to an automatic conveying device and an image forming apparatus.

2. Description of the Related Art In an image forming apparatus, an automatic conveying device is used to automatically convey a document to a reading unit through a conveying path when conveying a document to a reading unit or the like for reading an image.

In such an automatic transport device, a configuration is known in which the transport path is curved to reduce the distance to the end extending in the nip direction in order to adjust the front and back of the document and to reduce the size.
However, in order to reduce the size, it is necessary to increase the curvature. In particular, in the case of conveying highly rigid paper, etc., it does not conform to the shape of the conveying path and is difficult to be guided toward the nip downstream in the conveying direction. There was a problem that transport resistance was generated at the time of approach.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic document feeder capable of stably transporting a document even on a curved transport path.

An automatic conveying device according to the present invention is an automatic conveying device for conveying a recording medium, comprising: a driving roller arranged on the upstream side in the conveying direction of a reading unit; and a pair of driven rollers arranged facing the driving roller. a nip portion formed by the drive roller and the driven roller; and a guide surface forming a curved transport path for guiding and transporting the recording medium to the nip portion, wherein the curved guide An automatic document feeder having a gap between the outer surface upstream of the end and the recording medium when the leading edge of the recording medium is conveyed and contacts the end of the outer surface of the surface, It presses the recording medium so as to reduce the gap, is provided with a pressing member that is a rotating body, and has a concave-shaped bearing that supports the rotating shaft of the rotating body from below, and the bearing and the rotating shaft are provided. It is characterized by having a gap in the horizontal direction between the bearing and the rotating shaft that can move in the horizontal direction in the gap.

According to the automatic transport device of the present invention, it is possible to stably transport a document even on a curved transport path.

1 is a schematic configuration of an image forming apparatus in which the present invention is used; 2 is a diagram showing a functional configuration of an image forming unit shown in FIG. 1; FIG. It is a figure which shows an example of a structure of the automatic conveying apparatus of this invention. 4 is a diagram showing an example of a transport route of the automatic transport device shown in FIG. 3; FIG. It is a figure which shows an example of a structure of the automatic conveying apparatus shown by FIG. 4 is a diagram showing an example of a configuration of a pressing member shown in FIG. 3; FIG. It is a figure which shows the 1st modification of the press member of an automatic conveying apparatus. It is a figure which shows the 2nd modification of the press member of an automatic conveying apparatus. It is a figure which shows the comparative example of an automatic conveying apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an automatic conveying apparatus and an image forming apparatus using the automatic conveying apparatus according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the image forming apparatus 100 includes an operation unit 5 for user operation, and an image reading unit 3 for reading a document Q as a recording medium as a data image. , a transport unit (ADF) 4 for transporting the document Q from the loading tray 101 to the image reading unit 3, and an image for electrophotographic copying of the image data of the document Q read by the image reading unit 3. and a forming portion 2 .
In this embodiment, the image reading section 3 and the conveying section 4 will be described as an automatic document conveying apparatus that conveys a recording medium.

FIG. 2 is a schematic diagram of the image forming section 2 extracted from the image forming apparatus 100 shown in FIG.

Below the image forming unit 2, a sheet size is selectable automatically or manually by the user using the operation unit 5 according to the size of the document Q to be read. A device 7 is provided. That is, the paper feeding device 7 has a plurality of paper feeding trays 71 as sheet storage means that are stored and arranged in multiple stages inside the paper feeding device 7, and each paper feeding tray 71 is individually installed outside the paper feeding device 7. Each paper feed tray 71 is configured to be able to be drawn out, and the paper S for that tray can be set in each paper feed tray 71 and an appropriate number of sheets can be replenished. In each paper feed tray 71, a large number of paper sheets S are stacked and stored in different paper types (sheet types), each having various paper sizes and oriented vertically and horizontally with respect to the paper transport direction (sheet transport direction). .

The image forming section 2 has, for example, a process cartridge having a plurality of cylindrical photosensitive members.
The image forming section 2 has a photosensitive unit 20 and a fixing device 21, as shown in FIG.
The image forming unit 2 includes two support rollers 25 and 26 which are arranged facing each other with a predetermined distance therebetween in a substantially vertical direction, and a transfer belt which is an intermediate transfer member which is stretched between the support rollers 25 and 26 and rotates in the B direction. 27.
After transferring the toner image generated by the photoreceptor unit 20 onto the transfer belt 27 with respect to the sheet S conveyed from the upstream side to the downstream side on the conveying path R1, the toner image is further transferred from the transfer belt 27 to the sheet S. , and the fixing device 21 fixes the transferred toner image on the sheet S. As shown in FIG.
The paper S on which the toner image has been fixed is discharged from a paper discharge section 9 arranged at the end of the transport path R1.

The photoreceptor unit 20 has a drum-shaped photoreceptor 20A as an image carrier, and is rotatably supported by a side plate in the main body of the image forming apparatus about a substantially horizontal rotating shaft.
The photoreceptor 20A is formed in a cylindrical shape with a predetermined diameter, and is rotationally driven at a stable and constant speed in a rotational direction indicated by direction A in the figure when rotational driving force is transmitted from a driving source such as a motor. ing.
The photoreceptor unit 20 has a developing device 29, a transfer device 23, a cleaning device 28, a neutralizing device, and a charging device 24 in this order in the rotation direction along the direction A around the photoreceptor 20A. Within the range of one rotation in the counterclockwise rotation direction of the body 20A, each of these devices 22 to 24 successively changes the developing position, the transfer position, the cleaning position, the neutralization position, and the charging position from upstream to downstream. is set.
Further, a latent image forming position is set between the charging position and the developing position, and an exposure device for writing an invisible latent image corresponding to image information by irradiating the latent image forming position with a predetermined laser beam. 47 is arranged at a position away from the photoreceptor unit 20 .
The photoreceptor 20A is rotated in a predetermined counterclockwise direction, and image formation is performed in synchronization with the rotation of the photoreceptor 20A as described below.

That is, the developing device 29 has a configuration such as a developing roller for generating a toner brush in which toner particles are radially erected from the surface, and a toner brush is generated at a predetermined location on the surface of the photoreceptor 20A along with the rotation of the photoreceptor 20A. It moves on the circumference, attaches toner particles at the tip of the toner brush to the latent image passing the development position, and visualizes the invisible latent image with a monochrome toner image.

The photoreceptor cleaning device 28 is arranged at a cleaning position on the photoreceptor 20A to remove toner, foreign matters, etc. remaining on the surface of the photoreceptor 20A after transfer.
The static eliminator is mainly composed of a lamp capable of emitting light of a predetermined intensity. The lamp irradiates a static elimination position with light for static elimination, and the charged state of the surface of the photoreceptor 20A at the position irradiated with the light is measured. The surface potential of the photoreceptor 20A after it has been released and passed the transfer position is returned to the initial state.

The toner image formed on the outer peripheral surface of the photoreceptor 20A is further transferred onto the paper S via the transfer belt 27. As shown in FIG. The sheet S having the toner image transferred to the surface thereof in this way is conveyed to the downstream side of the conveying path R1 and fixed by the fixing device 21, which will be described later.

The fixing device 21 has a heating roller 31 containing an electric heater as a heat source, and a pressure roller 32 facing the heating roller 31 and pressed toward the heating roller 31 .
When the heating roller 31 is rotationally driven by the drive source, the pressure roller 32 in contact therewith is driven to rotate, and the contact point between the heating roller 31 and the pressure roller 32 is heated to a predetermined heating temperature. A nip portion for fixing the toner image on the sheet S is formed by securing the pressure.

As shown in FIGS. 1 and 3, the automatic document feeder shown in FIG. 1 is the upper structure of an image forming apparatus 100 comprising an image reading section 3 and an ADF 4 serving as a feeding section.
The image reading section 3 has a front side reading section 16 for reading the front side of the document Q when the document Q is conveyed, and a contact glass 6 attached above the front side reading section 16 .

The ADF 4, as shown in FIG. 3, is an automatic transport device attached to the upper portion of the image reading section 3 so as to be openable and closable.
The ADF 4 has a back side reading section 18 for reading the back side of the document Q, and a contact glass 17 arranged between the back side reading section 18 and the path through which the document Q passes. The ADF 4 includes a pickup roller 41 arranged at a position 9a spaced from the loading tray 101 by a predetermined distance, a feed roller 411 and a separation pad 412 for sequentially separating the document Q picked up by the pickup roller 41 from the top one. and have Here, the separation pad 412 is used to separate the document Q sheet by sheet, but a reverse roller may be used. In such a configuration, the feed roller 411 and separation pad 412 function as a separation section.
The pickup roller 41 is supported so as to rotate around a feed roller 411 , and an endless belt is stretched between the pickup roller 41 and the feed roller 411 .
The ADF 4 also includes a pull-out roller 413 located downstream of the feed roller 411 in the document transport direction and upstream of the front surface reading portion 16 of the image reading portion 3 and the rear surface reading portion 18 of the ADF 4 in the transport direction, and a pre-reading roller 414 . and have

The ADF 4 also has a registration sensor 15 for detecting movement by detecting the leading edge of the document Q being conveyed and synchronizing the reading start timing, and for discharging the document Q for which reading has been completed to the discharge tray 421. a pair of post-reading rollers 419, a discharge roller 420, and a motor in the ADF 4 as a drive source for driving these rollers.
In the configuration of the ADF 4, the rollers are driven by a motor as a drive source, but the configuration is not limited to such a configuration, and may have a plurality of drive sources or be driven by a pair of rollers. But it's okay.
The pre-reading roller 414, the driven roller 426, the back side reading section 18, the post-reading roller 419, and the paper discharge roller 420 are attached to the ADF 4 side, and the contact glass 6 and front side reading section 16 are attached to the image reading section 3 side. The ADF 4 and the image reading section 3 are connected via a rotatable hinge (not shown). With such a configuration, the ADF 4 and the image reading section 3 can be opened and closed separately.

The ADF 4 is also provided with a transport path 42 for transporting the document Q from the loading tray 101 on which the document Q is placed to the image reading section 3 and transporting the document Q along the C direction. and a roller pressing member 22 (see FIG. 4) that protrudes toward the outer wall side of the transport path 42 and presses the document Q by its own weight.
The conveying path 42 has a curved portion 43 curved with a predetermined curvature, and includes an outer wall surface 43 a serving as an outer guide surface forming a surface that contacts the front side of the document Q, that is, the outer peripheral side of the curved portion 43 , and an inner wall of the curved portion 43 . and an inner wall surface 43b serving as an inner guide surface forming a peripheral side.

In this embodiment, the pressing member 22 is, for example, a roller roller which is a rotating body supported so as to be rotatable in the direction D, as shown in FIG. Note that the configuration is not limited to this, and a rectangular member or a spherical member that prevents an increase in the contact frictional force with respect to the outer wall surface 43a may be used. For the purpose, it is most desirable to be a driven rotating body.

When copying a document Q using such an image forming apparatus 100, first, the document Q is placed on the placement tray 101 in page order with the front side facing up.
The ADF 4 moves the pick-up roller 41 from the standby position 9a to the contact position 9b where it contacts the upper surface of the document Q, and separates and conveys the uppermost document Q one by one.
The document Q separated and conveyed by the feed roller 411 and the separation pad 412 is then conveyed to the image reading section 3 by the pullout roller 413 and the pre-reading roller 414 .
A registration sensor 15 is arranged between the pre-reading roller 414 and the image reading section 3, and detects the leading edge of the document Q being conveyed to match the reading start timing.
The registration sensor 15 is also used for the purpose of detecting the document length and the interval between documents by detecting the trailing edge of the document Q. FIG.

As already described, the contact glass 6 is provided on the upper surface of the front surface reading unit 16 attached to the image reading unit 3 side, and the contact glass 17 is provided on the lower surface of the back surface reading unit 18 attached to the ADF 4 side. Therefore, the image reading unit 3 passes the document Q through the path formed between the contact glass 6 and the contact glass 17 by the ADF 4 and optically reads both sides of the document Q to obtain an image of the document Q. Store as data. Note that one-sided reading may be performed using only one of them.
When all the documents Q are read, the pickup roller 41 moves up from the contact position 9b to the standby position 9a and returns to the standby state.

The image forming section 2 writes a latent image on the photosensitive member 20A based on the image data read by the image reading section 3, develops it as a toner image, and forms a sheet of paper supplied from the paper feeding device 7 via the transfer belt 27. transcribed to S.
The toner image transferred to the paper S is fixed as an image by the fixing device 21 and discharged from the paper discharge section 9 .

In the image forming apparatus 100 as described above, the ADF 4 is required to reliably convey the document Q without paper jamming and to be miniaturized.
When the direction in which the document Q is conveyed from the loading tray 101 of the ADF 4 is to be made smaller, the curvature of the conveying path 42 is made larger (the radius of curvature is smaller than that of the conveying path 42'), as shown in FIG. 9 as a comparative example. ) is required. However, if the curvature of the transport path 42 is simply increased, depending on the rigidity of the document Q, when the document Q reaches the tip of the outer wall of the transport path 42 as shown in FIG. Since the document Q is lifted from the outer wall and a gap is created, the document Q is not guided well by the outer wall, and the end of the document conveyed from the edge of the outer wall is successfully conveyed to the nip portion N formed by the pre-reading roller 414 and the driven roller 426. I had a problem that it wouldn't.

Therefore, in the present embodiment, as illustrated in FIGS. 4 to 6 as an embodiment of the present invention, the pressing member 22 is used to press the document Q so that the document Q runs along the outer wall of the transport path 42. solve the problem.

A description will be given of such a configuration.
In FIG. 4, the curved portion 43 of the transport path 42 is configured such that the document Q is easily guided toward the nip portion N formed by the pre-reading roller 414 and the driven roller 426 .

In FIG. 4, when the document Q reaches the tip of the outer wall of the transport path 42, the document Q does not follow the outer wall of the transport path 42, and a gap is formed by floating from the outer wall. A pressing member 22 is arranged on the downstream end side, and this pressing member 22 presses the document Q toward the outer wall surface 43a side at the curved portion 43 in the transport path 42 by its own weight.
By providing the pressing member 22 in the vicinity of the exit of the curved portion 43 in this manner, for example, when using a document Q having high rigidity and being easily separated from the outer wall surface 43a, the pressing member 22 can be moved along the outer wall surface 43a. presses the document Q.
With such a configuration, even if the curvature of the curved portion 43 is increased, the document Q can easily enter the nip portion N, and problems such as paper jams of the document Q can be suppressed, thereby stably conveying the document. can be done.

Here, as shown in FIG. 5 for explaining the details of the relationship between the curved portion 43 of the transport path 42 and the pressing member 22, the transport path 42 includes an outer wall surface 43a forming the outer peripheral side of the curved portion 43, and an inner wall surface 43b forming the inner peripheral side of the .
From the first point P1, which is the inner wall surface farthest in the horizontal direction from the nip portion N pressed by the pre-reading roller 414 and the driven roller 426, to the second point P2, which is the end portion of the outer wall surface 43a at the end of the conveying path 43. is shorter than the vertical distance LY from the first point P1 to the second point P2. With such a configuration, the curved portion 43 of the transport path 42 is greatly curved, so the ADF 4 can be made smaller in the horizontal direction.

The pressing member 22 is arranged between the first point P1 and the second point P2 on the transport path 42 .
In particular, the lowermost portion of the pressing member 22 that contacts the document Q is above the second point P2 in the horizontal direction. If the pressing member 22 is a roller, the contact force is reduced by the rotation of the roller. Therefore, if there is a gap between the lowermost portion of the roller and the outer wall surface 43a, it should be placed below the second point P2 in the horizontal direction. can also
With such a configuration, when the document Q is conveyed to the end of the outer wall surface 43a, the document Q is pressed by the pressing member 22, so that the contact angle between the document Q and the outer wall surface 43a changes. The force is reduced, and the document Q can be reliably advanced in the direction of the nip portion N to be guided in the transport path 42 .

Further, the front side reading section 16 or the back side reading section 18 is arranged downstream and above the nip portion N in the conveying direction in this embodiment. In other words, as shown in FIG. 3, the conveying path after the nip portion N is formed to extend in the vertical direction rather than in the horizontal direction.
According to such a configuration, since the conveying path after the nip portion N becomes oblique, it contributes to space saving of the image forming apparatus 100 .

Further, in this embodiment, the pressing member 22 is a rotating body that rotates about the rotation axis O so that the minimum gap between the pressing member 22 and the outer wall surface 43 a is the same in the axial direction of the pre-reading roller 414 .
With such a configuration, when the document Q comes into contact with the pressing member 22, it can easily enter parallel to the outer wall surface 43a. is possible.
When the resistance, ie, the contact force, during transport of the document Q is large, problems such as damage to the document Q and jamming may occur. Therefore, it is more preferable to reduce the contact force.

Further, as shown in FIG. 6, in the present embodiment, the housing of the ADF 4 (see FIG. 3) and the inner wall surface 43b (see FIG. 4) have a bearing 44 that supports the rotation axis O of the pressing member 22. A gap 45 is provided at least partially between the rotating shaft O and the bearing 44 .
According to this configuration, when the document Q and the pressing member 22 come into contact with each other, the rotating shaft O can move in the gap 45, so that the pressing member 22 moves upward and presses the document Q with its own weight. Further, the pressing member 22 moves horizontally to further reduce the contact resistance when the document Q enters. With such a configuration, problems such as paper jams and contamination of the document Q are less likely to occur.

In addition, in the present embodiment, the pressing member 22 is arranged at the central portion of the transport path 42 in the width direction.
According to such a configuration, since the central portion of the document Q in the width direction is pressed, the document Q can be reliably pressed toward the outer wall surface 43a even when the paper sizes are different.

7 and 8 show other modifications of the pressing member 22. FIG.
In the configuration of FIG. 7 , a plurality of pressing members 22 are arranged in the width direction of the transport path 42 . According to such a configuration, even when the width of the original document Q is narrow, the pressing member 22 presses the original document Q at a plurality of points so that the original document Q is aligned with the outer wall of the transport path 42, so that various paper types and sizes can be used. , and various types of documents Q can be stably transported even on a curved transport path.

In the configuration of FIG. 8, the pressing member 22 protrudes from a part of the side surface of the pressing member 22 downward, that is, in the direction toward the outer wall surface 43a, and has a rib-shaped projection 22b formed along the rotation direction. have.
With such a configuration, when the document Q is pressed against the pressing member 22, the contact force is reduced and the document Q can be pressed against the outer wall surface 43a. Since it is positioned in the downward direction, the contact resistance is further reduced, and problems such as paper jams and contamination of the document Q are less likely to occur.

Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments as they are. . Also, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, different embodiments and modifications may be appropriately combined.

3 reading unit 4 automatic transport device (ADF)
22 pressing member 22b rib (projection)
42 transport path 43 curved portion 43a outer wall surface (outer guide surface)
43b inner wall surface (inner guide surface)
100 image forming apparatus 414 drive roller 426 driven roller N nip portion O axis (rotational axis)
P1 First point P2 Second point Q Recording medium (original)

JP 2006-213474 A JP-A-2000-168992 Japanese Patent No. 4621219

Claims (8)

An automatic transport device for transporting a recording medium,
a driving roller arranged upstream of the reading unit in the conveying direction;
a pair of driven rollers arranged facing the driving roller;
a nip portion formed by the driving roller and the driven roller;
a guide surface forming a curved transport path for guiding and transporting the recording medium to the nip;
has
An automatic document feeder having a gap between the recording medium and the outer surface upstream of the edge when the leading edge of the recording medium is transported and comes into contact with the edge of the outer surface of the curved guide surface. There is
providing a pressing member, which is a rotating body, pressing the recording medium so as to reduce the gap;
It has a concave-shaped bearing that supports the rotating shaft of the rotating body from below, and the bearing has a gap in the horizontal direction between the rotating shaft and the bearing, and the gap is formed when the rotating shaft moves in the horizontal direction. An automatic transport device characterized by being able to move to. In the automatic transport device according to claim 1,
The transport path has an outer wall surface forming an outer peripheral side of the curved portion and an inner wall surface forming an inner peripheral side of the curved portion,
The horizontal distance from the first point, which is the inner wall surface that is the farthest in the horizontal direction from the nip portion, to the second point, which is the end portion of the outer wall surface at the end of the conveying path, is from the first point to the second point. An automatic transport device characterized by being shorter than the vertical distance to two points. In the automatic transport device according to claim 2 ,
The automatic conveying device, wherein the pressing member is arranged between the first point and the second point on the conveying path. In the automatic transport device according to any one of claims 1 to 3,
The automatic conveying device, wherein the reading section is arranged above the nip section. In the automatic transport device according to any one of claims 1 to 4,
The automatic conveying device, wherein the pressing member has a rib formed along the direction of rotation. In the automatic transport device according to any one of claims 1 to 5,
The automatic conveying device, wherein the pressing member is arranged at a central portion in the width direction of the conveying path. In the automatic transport device according to any one of claims 1 to 6,
The automatic conveying device, wherein a plurality of the pressing members are arranged in the width direction of the conveying path. An image forming apparatus comprising the automatic transport device according to any one of claims 1 to 7.

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