JP2000143032A - Sheet material transport device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a decrease in sheet material transportability and breakage of a sheet material in a device having a rotary conveyance member that conveys a sheet material exposed from an opening of a guide member. I do. SOLUTION: A bracket 3d (holding member) for holding an inner discharge roller 3a (rotary transport member) includes a guide portion 3d1 located in a gap between an opening 4a1 of an upper guide 4a and the inner discharge roller 3a. Prepare.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus and an image forming apparatus provided with the sheet conveying apparatus, and more particularly to a technique for improving sheet conveying properties.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine has an image reading section for reading image information of a document at an upper portion of an apparatus main body, and an image forming section by, for example, an electrophotographic method is provided at a substantially central portion of the apparatus main body. In some cases, sheet material stacking means (sheet deck) for storing the sheet material to be fed to the image forming unit is attached to a lower portion thereof. In such an image forming apparatus, a sheet material fed from a lower sheet deck is conveyed through a sheet material conveyance path by a conveyance roller through a predetermined guide member, and a nip of a pair of registration rollers in contact with a certain pressure. The skew is corrected by the pair of rollers, and the skew is guided to the image forming unit in synchronization with the image forming operation.

[0003] The sheet material on which the toner image is transferred and formed by the image forming unit passes through a conveying unit, passes through a fixing unit for fixing the toner image to the sheet material, and is discharged to the outside of the machine via a sheet discharging unit. You.

[0004] A roller pair for transporting the sheet material is provided in the paper discharge section at the most downstream of the process of the image forming apparatus, and rotates in synchronization with the transport of the sheet material from the fixing section to transport the sheet material. (Discharge).

FIG. 6 is a view showing a paper discharge unit 10 of the image forming apparatus 100.
1 is a view of the configuration of the image forming apparatus 1 viewed from the inside of the apparatus main body.
At 02, the sheet material S on which the toner image is fixed is guided to the outside of the apparatus or to a reversing unit (not shown).

In the sheet discharging section 101, a conveying path of the sheet material S is mainly constituted by a roller pair 103 for conveying the sheet material S and a guide member 104.

FIG. 7 is a view taken in the direction of arrows V1-V1 in FIG.
On the downstream side of the fixing unit 102, in addition to the roller pair 103 constituted by a pair of an inner discharge roller 103a and an inner discharge roller 103b on the fixing unit 102 side, a discharge roller pair 1
05 and the like, a plurality of types and a plurality of pairs of conveying means are appropriately provided according to the conveying path of the sheet material S. In this description, for ease of understanding, the roller pair 103 arranged on the fixing unit 102 side is used. Will be explained.

On the other hand, as shown, the guide member 104 includes an upper guide 104a and a lower guide 104b for vertically guiding the conveying path of the sheet material S.

FIG. 8 is a diagram for explaining the D1 part of FIG. 7 in detail. The inner discharge roller 103a is urged against the inner discharge roller 103b to form a nip portion 103c (the upper guide 104a and the lower guide 104b are formed in a cross section).

In this mechanism, the inner discharge roller 103a is held by a bracket 103d.
It rotates about the rotation axis 103f with respect to the fixed part 103e. The inner discharge roller 103a of the bracket 103d is biased toward the inner discharge roller 103b by a spring 103g.

[0011] The sheet material S is taken from the direction of the arrow in FIG.
It is guided to the nip portion 103c, and guided by the upper guide 104a and the lower guide 104b, and discharged out of the apparatus.

[0012]

FIGS. 9 and 11 are perspective views showing the mounting relationship between the inner discharge roller 103a and the upper guide 104a. The inner discharge rollers 103a are provided with openings 104a1 and 104a2 provided in the upper guide 104a.
(FIG. 9) and the opening 104a3 (FIG. 11).
One or more inner discharge rollers 103a are configured to be exposed from outside the transport path to the inside of the transport path.

The behavior when the sheet material S having such a configuration passes through the inner discharge roller 103a will be described. 10 is a sectional view taken along line V2-V2 of FIG. 9, and FIG. 12 is a sectional view taken along line V3-V3 of FIG.

Sheet material S discharged from fixing section 102
Are often curled in an arc shape in the conveying width direction as shown in the figure. Therefore, in the case of FIG.
When the end Sa of the sheet material S comes to a position other than the nip portion 103c of No. 03, the sheet material S passes through this area while contacting the guide portion 104c between the inner discharge rollers 103a.

A guide portion 104 is provided beside the inner discharge roller 103a.
When c is provided, the sheet material S can smoothly pass along the guide.

However, as shown in FIGS. 11 and 12, when the opening 104a3 exposes the plurality of inner discharge rollers 103a, an unguided area 104c2 is formed between the inner discharge rollers 103a. That means
When the edge Sa of the sheet material S passes through this area, the sheet material S may collide with the opening portion 104a3 of the upper guide, and the sheet material S may have a reduced paper discharging property, and the sheet material S may be bent. It is feared that damage will occur.

Further, it is difficult to effectively remove the curl of the sheet material discharged from the fixing unit by using the conventional roller pair 103.

An object of the present invention is to solve the above-mentioned problem of the prior art. It is an object of the present invention to provide a method of manufacturing a device between an opening of a guide member and a conveying member exposed from the opening to convey a sheet material. The object of the present invention is to prevent the sheet material from entering the gap of the sheet material, to prevent the sheet material from being deteriorated in transportability and to prevent the sheet material from being damaged, and to remove the curl of the conveyed sheet material.

[0019]

In order to achieve the above object, according to the present invention, there is provided a guide member having a sheet material conveyance path and an opening formed therein, and a sheet conveyed from the opening of the guide member. In a sheet material transporting apparatus including: a rotary conveying member exposed in a path; and a holding member that holds the rotary conveying member, the holding member includes a gap between an opening of the guide member and the rotary conveying member. Is provided.

It is also preferable that a plurality of rotary conveying members are coaxially arranged at predetermined openings in the opening of the guide member.

The rotary transport member has a second rotary transport member that is in pressure contact with the second transport member, and the guide portion of the holding member is located between a nip surface formed by the rotary transport member and the second rotary transport member. It is also preferable that the curl is corrected by contacting the sheet material to be conveyed, which is disposed on the second rotary conveyance member side.

It is also preferable that the guide portion of the holding member is disposed outside the center of conveyance of the sheet material on the conveyance path with respect to the rotary conveyance member.

Preferably, the guide portion of the holding member has an inclined surface for guiding the conveyed sheet material to a predetermined position in the thickness direction of the conveyance path.

An image forming apparatus is characterized by comprising the above-described sheet material conveying device, and image forming means for forming an image on a sheet material conveyed by the sheet material conveying device.

[0025]

Embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1 is a perspective view illustrating a roller pair 3 and a guide member 4 provided in a paper discharge section of an image forming apparatus provided with a sheet conveying apparatus according to a first embodiment. FIG. FIG. 2 is a cross-sectional view taken along line V4-V4 of FIG. 1, and a characteristic configuration of the first embodiment will be specifically described with reference to these drawings.

Although the schematic structure of the image forming apparatus will be described later, the basic structure other than the roller pair 3 and the guide member 4 is the same as that described in the section of the prior art.

Referring to FIG. 2, the transport path K on which the sheet material S is transported is defined by an upper guide 4a constituting the guide member 4.
And the lower guide 4b.
The sheet material S is nipped by the roller pair 3 and is conveyed by the rotation of the roller pair 3 driven by driving means (not shown).

The roller pair 3 is an inner discharge roller 3a as a rotary conveying member and a second discharge roller 3a which is in pressure contact with the inner discharge roller 3a.
And a plurality of inner discharge rollers 3b as the rotary conveyance member, and are arranged in a plurality in the conveyance width direction of the sheet material S.

The inner discharge roller 3a is held by a bracket 3d as a holding member that rotates about a rotating shaft 3f with respect to the fixed portion 3e, and the inner discharge roller 3a is internally discharged by a spring 3g. It is urged toward the paper roller 3b.

The upper guide 4a has an opening 4 long in the transport width direction for exposing the two inner discharge rollers 3a to the transport path K.
a1 is formed.

The lower guide 4b has openings 4b1 (plurality) corresponding to the respective inner discharge rollers 3b.

The sheet material S is guided from the direction of arrow A1 in FIG. 1 to the nip portion 3c, is guided by the upper guide 4a and the lower guide 4b, and is discharged out of the apparatus.

At the opening 4a, the two inner discharge rollers 3a are moved in the conveying width direction of the sheet material S (arrow A2 in the drawing).
Direction) with a predetermined gap therebetween.

A guide portion 3d1 for guiding the conveyance of the sheet material S outside the conveyance center in the conveyance path K of the bracket 3d in the conveyance width direction (the direction of arrow A2 in the drawing) of the sheet material S is integrally provided. I have.

The guide portion 3d1 is provided for the sheet material S to be conveyed.
Is guided to a predetermined position in the thickness direction of the transport path K (in FIG. 2, the bracket 3d side with respect to the nip portion 3c).

The guide portion 3d1 allows the end Sa of the sheet S to enter the opening 4a when the end Sa of the sheet S is located in the gap between the openings 4a between the two inner discharge rollers 3a. That is, it is possible to prevent the sheet material S from being stably transported and to prevent the sheet material S from being damaged.

When the guide portion 3d1 is disposed on the side of the center of the sheet material S being conveyed, the possibility that the end Sa of the sheet material S will interfere with the end surface of the guide portion 3d1 increases.
It is preferable to adopt the arrangement shown in FIGS.

(Embodiment 2) Next, a second embodiment will be described with reference to FIG. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

As a characteristic configuration of the second embodiment, the position of the guide portion 3d2 is separated from the surface of the nip portion 3c by a distance D2 below.

In the first embodiment, the guide 3d
Since the position of No. 1 is separated from the nip portion 3c surface upward by a distance of D1, the sheet material S conveyed from the fixing portion is curled such that the upper surface is depressed as shown in FIG. In this case, as described above, although it has a function as a guide, it has no or little effect on the curl correction of the sheet material S.

On the other hand, the guide 3d shown in FIG.
In No. 2, it is arranged so as to protrude downward from the upper surface of the nip portion 3c by a distance of D2. With this configuration, as shown in FIG. 4B, when the end Sa of the sheet material S on which the curl is formed such that the upper surface is depressed is positioned in the gap between the two inner discharge rollers 3a. The curl can be corrected.

(Embodiment 3) FIG. 5 is an explanatory sectional view of the configuration of an image forming apparatus 200 provided with a sheet conveying apparatus to which the present invention is applied. Hereinafter, the configuration of the image forming apparatus 200 will be briefly described with reference to FIG. Image forming apparatus 20
0, a photosensitive drum 205 is provided at the center thereof, and a pre-exposure lamp 20 is provided on the outer periphery of the photosensitive drum 205.
1. A photosensitive drum charger 202, an exposure device 203, a developing device 204, a transfer charger 207, and a cleaner 208 are provided.

A transfer belt 206 is provided adjacent to the photosensitive drum 205, and the toner image formed on the photosensitive drum 205 is transferred by the transfer charger 207 to the transfer belt 206.
The image is transferred onto the sheet material S carried / conveyed thereon.

The sheet material S to which the toner image has been transferred is fixed in the fixing unit 209 by heating and pressing to fix the toner image.
The recording image is discharged out of the apparatus.

In the exposure device 203, a rotating polygon mirror scans a laser beam emitted from a light source device (not shown) provided in the upper part of the device body, and the light beam of the scanning light is changed by a reflection mirror, and is changed by an fθ lens. Photosensitive drum 2
A latent image corresponding to an image signal is formed on the photosensitive drum 205 by condensing and exposing on the generating line 05.

The developing device 204 is filled with a predetermined amount of toner by a toner supply device (not shown), and the latent image on the photosensitive drum 205 is developed to be visualized as a toner image.

The sheet material S is supplied from a sheet material cassette 221 (or a manual sheet feeding tray 222 for manual sheet feeding) provided in a sheet feeding device 220 disposed at a lower portion of the apparatus main body to a sheet feeding roller 223 and a separation roller pair 224. Is supplied to the transfer belt 206 through a plurality of pairs of transport rollers 225 and 226 and a pair of registration rollers 213, and is sequentially transported by the transfer belt 206 to a transfer unit facing the photosensitive drum 205.

In the image formation, when the transfer belt 206 is rotated by the drive roller 211 and reaches a certain speed, one sheet material S separated and fed from the sheet material cassette 221 is conveyed by the registration roller pair 213 in the conveying posture and timing. Are fed to the transfer belt 206 and the sheet material S is conveyed toward the transfer unit.

In synchronization with this, the image writing signal is turned ON, and an image is formed on the photosensitive drum 205 at a predetermined timing based on the signal.

Then, the toner image formed on the photosensitive drum 205 is transferred to the sheet material S by the transfer charger 207 applying an electric field or electric charge at the lower transfer portion of the photosensitive drum 205. The sheet material S is a registration roller pair 21
3 is transferred onto the transfer belt 206, and is immediately held electrostatically on the transfer belt 206 by being held together with the transfer belt 206 by the attraction charger 214 and the attraction roller 215 facing the attraction charger and applied with an electric field or charge. Conveyed.

Next, the sheet material S on which the toner image has been transferred by the transfer charger 207 is discharged by the separation charger 216 downstream of the transfer belt 206 in the transport direction, and the electrostatic attraction force is attenuated. It leaves from the end of 206.

Sheet material S detached from transfer belt 206
Is transported to the fixing device 209. The fixing device 209 includes a fixing roller, a pressure roller, a heat-resistant cleaning member that cleans each of the rollers, a heater installed in each roller, and an application roller that applies a release agent oil such as dimethyl silicone oil to the fixing roller. And a thermistor that detects the surface temperature of the pressure roller and controls the fixing temperature.

The sheet material S on which the toner image is formed is fixed to the sheet material S by fixing, a copy image is formed, and the copy image is discharged to the paper discharge tray via the paper discharge unit 230.

On the other hand, the photosensitive drum 205 on which the transfer is completed is cleaned and removed of the transfer residual toner by the cleaner 208, and is ready for the next latent image formation.

Further, the transfer belt 206 after the sheet material S is separated is brought into contact with the conductive fur brush 210 installed on the sheet material carrying side and the drive roller 211 which is grounded as opposed to the conductive fur brush 210, so that the transfer belt 206 is placed on the transfer belt 206. The toner and other foreign matters remaining in the toner are cleaned, and the accumulated charge is removed (static elimination). As the conductive fur brush, a conductive web (nonwoven fabric) can be used.

In the sheet discharging section 230, when an instruction to form an image on both sides of the sheet material S is issued, the sheet S is sent to the image forming section via the reverse conveying path 231 and the re-conveying path 232. The sheet material S on which an image is formed on one side is fed.

The reverse transport path 231 and the re-transport path 232 are appropriately provided with path switching members 233 and 234, a plurality of transport roller pairs 235, and the like.

In the image forming apparatus 200, the roller pair 3 and the guide member 4 described in the first and second embodiments are provided in a paper discharge unit 230 disposed downstream of the fixing device 209. However, the present invention is not limited to this, and it is needless to say that the present invention can be applied to other transport rollers and transport roller pairs.

[0060]

As described above, it is possible to prevent deterioration of sheet material transportability and breakage of a sheet material in an apparatus provided with a rotary conveying member that conveys a sheet material exposed from an opening of a guide member. It becomes possible.

Further, it is possible to remove the curl of the sheet material conveyed by the guide member.

Further, it is possible to reduce restrictions on the arrangement of the rotary conveying member with respect to the guide member.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a characteristic configuration of a sheet material conveying device according to a first embodiment.

FIG. 2 is a sectional view taken along line V4-V4 of FIG.

FIG. 3 is a diagram showing a characteristic configuration of a sheet material conveying device according to a second embodiment.

FIG. 4 is a diagram illustrating curling of a sheet material.

FIG. 5 illustrates an image forming apparatus.

FIG. 6 is a perspective view illustrating the configuration of a paper discharge unit of a conventional sheet material conveying device.

FIG. 7 is a sectional view taken along line V1-V1 of FIG. 6;

FIG. 8 is an enlarged view of a portion D1 in FIG. 7;

FIG. 9 is a perspective view illustrating a configuration of a conventional guide member and a roller pair.

FIG. 10 is a sectional view taken along line V2-V2 of FIG. 9;

FIG. 11 is a perspective view illustrating the configuration of a conventional guide member and roller pair.

FIG. 12 is a sectional view taken along line V3-V3 of FIG. 11;

[Explanation of symbols]

 3 Roller pair 3a Internal discharge roller (first rotary transport member) 3b Internal discharge roller (second rotary transport member) 3c Nip portion 3d Bracket (holding member) 3d1 Guide portion 3e Fixed portion 3f Rotating shaft 3g Spring 4 Guide member 4a Upper guide 4b Lower guide 4a1 Opening 4b1 Opening K transport path S Sheet material Sa end

Claims (6)

[Claims] A guide member forming a sheet material conveyance path and having an opening formed therein; a rotation conveyance member exposed to the conveyance path from the opening of the guide member; and a holding member for holding the rotation conveyance member. And a member, wherein the holding member has a guide portion located in a gap between an opening of the guide member and a rotary conveyance member. . 2. The sheet conveying apparatus according to claim 1, wherein a plurality of rotary conveying members are coaxially arranged at predetermined openings in the opening of the guide member. 3. A rotary conveying member, comprising:
A guide portion of the holding member, the rotation transfer member and the second
Than the nip surface formed by the rotary conveyance member
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is disposed on the side of the rotary conveying member and abuts against the conveyed sheet to correct the curl. 4. The holding member according to claim 1, wherein the guide portion of the holding member is disposed outside the conveyance center of the sheet material on the conveyance path with respect to the rotary conveyance member. The sheet material conveying device according to the item. 5. The guide part of the holding member has an inclined surface for guiding a sheet material to be conveyed to a predetermined position in a thickness direction of a conveyance path.
The sheet material conveying device according to the item. 6. A sheet material transport device according to claim 1, further comprising: an image forming unit configured to form an image on a sheet material transported by the sheet material transport device. Image forming apparatus.