JPH1077149A - Sheet conveying apparatus and image forming apparatus having the same - Google Patents

Abstract

(57) Abstract: An object of the present invention is to prevent an OHP sheet or the like from closely adhering to a curved sheet guide surface of a sheet guide in an image forming apparatus, thereby preventing a sheet jam or the like from occurring. SOLUTION: A plurality of guide members 35 integrally provided with a curved sheet guide surface 36, and a transport roller 30 for guiding a sheet to the plurality of guide members are provided, and a sheet transport direction of the transport rollers is controlled by the plurality of guide members. Thus, in a sheet conveying device that performs sheet conveyance by inverting the sheet by a predetermined angle, the sheet guide surface of the guide member includes:
Notches 37 and 38 are provided so that the sheet being conveyed is in non-contact, so that the sheet can be conveyed while preventing close contact with the sheet guide surface.

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 for conveying a sheet along a plurality of curved guide ribs, and an image forming apparatus provided with the sheet conveying apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a printer includes a paper feed tray 3 at a lower portion of an apparatus main body 2 as shown in FIG. In some cases, the installation area is reduced as much as possible.

[0003] Sheet conveyance in this image forming apparatus is as follows.
The sheet feeding unit 4 and the sheet discharging unit 6 are provided with curved conveying paths, and are configured so that the sheet draws an S-shape in the process from sheet feeding to sheet discharging. The sheet discharge unit 6 includes a sheet guide 34 and an inner guide 29 on the outside and inside of the curved portion of the conveyance path. Here, since the image surface of the sheet faces the inside of the curve, the sheet conveyance speed of the conveyance roller 30 is slightly faster than that of the discharge roller 32 so that the image surface is not rubbed against the inner guide,
The back surface of the sheet slides with the sheet guide 34 outside the conveyance path. Further, the sheet guide 34 has a conveying surface formed by a plurality of curved guide ribs 35 made of a resin material or the like. 10 and 11
As shown in (1), the sheet guide surface 36 of the guide rib 35 is formed so as to have a smooth surface as much as possible so that the leading edge of the sheet is not caught and the sheet can be smoothly conveyed.

[0004]

However, in the above-mentioned conventional example, when a sheet such as an OHP sheet having a very smooth sheet surface is conveyed along the curved sheet guide surface 36, the sheet may be in the vicinity of the curved portion of the rib. When the sheet is strongly pressed against the sheet guide surface 36, a sheet jam as shown in FIG. 11 may occur. Further, even when an image is further formed on the front surface of a sheet on which an image has been formed on the back surface (during double-sided printing), an abnormal sliding noise is generated because the toner-fixed portion on the back surface easily adheres to the rib surface. There was something to do.

Therefore, a first object of the present invention is to provide a notch in the sheet guide surface of the guide rib to reduce the contact area between the sheet guide surface and the sheet surface, thereby preventing the occurrence of sheet jam and sliding noise. An object of the present invention is to provide a transport device and an image forming apparatus provided with the transport device.

A second object of the present invention is to provide a fine uneven pattern on the -sheet guide surface of the guide rib, reduce the contact area between the guide surface and the sheet surface, and prevent the occurrence of sheet jam and sliding noise. An object of the present invention is to provide a sheet conveying device and an image forming apparatus provided with the same.

A third object of the present invention is to provide a guide roller in the middle of a guide rib so that a circumferential portion of the guide roller becomes a part of a sheet guide surface to reduce sheet jam and sliding noise. An object of the present invention is to provide a sheet conveying apparatus capable of preventing occurrence of the sheet and an image forming apparatus including the same.

[0008]

In order to achieve the above object, a sheet conveying apparatus according to a first aspect of the present invention includes a plurality of guide members integrally having a curved sheet guide surface;
A conveying roller for guiding a sheet to the plurality of guide members, wherein the sheet conveying direction by the plurality of guide members is reversed by a predetermined angle by the plurality of guide members to convey the sheet. A notch is provided on the sheet guide surface so that the sheet being conveyed is out of contact.

A sheet conveying apparatus according to a second aspect of the present invention includes a plurality of guide members integrally having a curved sheet guide surface, and a conveying roller for guiding a sheet to the plurality of guide members. In a sheet conveying apparatus that conveys a sheet by reversing the sheet conveying direction by a predetermined angle by the plurality of guide members, a fine uneven pattern is provided on the surface of a sheet guide surface of the guide member, and The height is 30 μm or more and 500 μm or less.

A sheet conveying apparatus according to a third aspect of the present invention includes a plurality of guide members integrally having a curved sheet guide surface, and a conveying roller for guiding a sheet to the plurality of guide members. A sheet conveying device that conveys a sheet by reversing the sheet conveying direction by a predetermined angle by the plurality of guide members, including a guide roller rotatable in the sheet conveying direction in the middle of a sheet passage area of the guide member. The circumferential portion of the guide roller protrudes inwardly of the curve from the guide surface, and is configured to be a part of the sheet guide surface.

According to a fourth aspect of the present invention, there is provided a sheet conveying apparatus according to any one of the first to third aspects, wherein each of the guide members comprises a plate-like member, and a plurality of parallel guide members are curved. The sheet guide surface forms one plane perpendicular to the sheet conveying direction.

According to a fifth aspect of the present invention, there is provided a sheet conveying apparatus according to any one of the first to third aspects, wherein the conveying roller is provided below a guide member, and the sheet conveyed by the conveying roller is The guide member is inverted by a predetermined angle while being guided upward from below the sheet guide surface of the guide member.

According to a sixth aspect of the present invention, an image forming apparatus includes the sheet conveying apparatus according to any one of the first to fifth aspects, and an image forming means for forming an image on a sheet.

A plurality of guide members provided integrally with each other, and a transport roller for guiding a sheet to the plurality of guide members. The sheet transport direction of the transport rollers is reversed by a predetermined angle by the plurality of guide members. In the sheet conveying apparatus for conveying a sheet, a notch portion in which a sheet being conveyed is not in contact is provided on a sheet guide surface of the guide member.

According to a second aspect of the present invention, a plurality of guide members integrally having a curved sheet guide surface, and a conveying roller for guiding a sheet to the plurality of guide members are provided. In a sheet conveying apparatus that conveys a sheet by reversing a conveying direction by a predetermined angle by the plurality of guide members, a fine irregular pattern is provided on a surface of a sheet guide surface of the guide member, and a height of the irregularities is provided. Is not less than 30 μm and not more than 500 μm.

According to a third aspect of the present invention, there is provided a plurality of guide members integrally provided with a curved sheet guide surface, and a transport roller for guiding a sheet to the plurality of guide members. In the sheet conveying apparatus that conveys a sheet by reversing a conveying direction by a predetermined angle by the plurality of guide members, a guide roller rotatable in a sheet conveying direction is provided in the middle of a sheet passage area of the guide member, The sheet conveying device is characterized in that a circumferential portion of the guide roller protrudes inward of the curve from the guide surface and becomes a part of the sheet guide surface. According to a fourth aspect of the present invention, there is provided an image forming apparatus including the sheet conveying device according to any one of claims 1 to 3 and an image forming unit that forms an image on a sheet.

[0017]

Based on the above means, when a sheet such as an OHP sheet having a very smooth sheet surface or a sheet having an image formed on the back surface is conveyed along a curved guide rib, the contact area between the sheet and the rib surface is reduced. The sheet is reduced and the contact is intermittent, so that the sheet hardly adheres to the rib surface, thereby preventing the occurrence of sheet jam and abnormal sliding noise.

Further, since the rib surface is formed with fine irregularities, the sheet and the rib surface are not in surface contact, and the sheet is less likely to adhere to the rib surface, thereby preventing the occurrence of sheet jam and abnormal sliding noise. You.

Further, since the guide roller is a part of the sheet guide surface, sliding of the sheet and the rib surface at the guide roller portion is eliminated, and sheet jam and abnormal sliding noise due to the sheet coming into close contact with the rib surface are eliminated. The occurrence is prevented.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) An embodiment according to the present invention will be described below with reference to the drawings.

In this description, a laser beam printer as shown in FIG. 3 will be described as an example of an image forming apparatus having a sheet conveying device. The printer 1 includes a sheet cassette 3, a sheet feeding unit 4, an image forming unit 5, and a sheet discharging unit 6 serving as a sheet conveying device, which are detachably attached to a lower portion of the apparatus main body 2. Is formed with a sheet stacking section 7 for stacking the discharged and formed sheets.

The image forming section 5 includes a laser scanner 11, a reflection mirror 12, a process cartridge 13, a transfer roller 14, a carrier 15, and a fixing device 16.

Inside the process cartridge 13, a developing device 18, a charging roller 19, a cleaner 20 and the like are provided around a photosensitive drum 17, and the light emitted from the laser scanner 11 is reflected by the reflecting mirror 12 and is exposed to light. A latent image is formed by scanning on the drum 17, and a toner image is formed by toner supplied from the developing device 18, and is transferred onto a sheet by the transfer roller 14. The sheet after the transfer is sent to the fixing device 16 along the conveyor 15, and the toner is fixed by the fixing roller 21 and the pressure roller 22.

As shown in FIGS. 1 and 2, the sheet discharge section 6 includes a transport roller 30, a sheet guide 34, an inner guide 29, and a discharge roller 32.
0, the discharge roller 32 has a transport roller 31 and a discharge roller 33 that are driven to face each other. The sheet guide 34 is integrally formed of a resin material, and includes a plurality of guide ribs 35 having a curved sheet guide surface 36. Each of the guide ribs 35 is provided with notches 37 and 38 having a stepped shape. As shown in FIG. 2, the notch portion is formed by a surface that is steeply inclined with respect to the curved sheet guide surface 36 and gentle inclined surfaces 39 and 40 that are directed from the innermost end of the steeply inclined surface to the guide surface. However, the steeply inclined surface can be gently inclined as long as the front contact between the sheet and the sheet guide surface is avoided.

Here, the operation of the above embodiment will be described.

The uppermost one of the sheets S in the sheet cassette 3 is taken out by a sheet feeding roller 23 and
4. The toner image is transferred to the image forming unit 5 along the guide 26 by the roller 25, and the toner image is transferred and fixed. The sheet on which an image is formed on the upper surface is sent to the sheet discharge unit 6, and is guided to the sheet guide 34 by the transport roller 30 and the transport roller 31. The upstream end of the sheet changes its traveling direction upward along the curved sheet guide surface 36 of the guide rib 35 and reaches the notches 37 and 38. The front end of the sheet once falls into the cutouts at the cutouts 37, 38, but the front ends contact the slopes 39, 40, which have a small difference in angle with respect to the traveling direction, so that the cutouts are smoothly formed without being caught. Pass through 37 and 38. In the vicinity of the notches 37 and 38, the contact length between the sheet surface and the sheet guide surface 36 is reduced, so that the sheet does not come into close contact with the sheet guide surface 36, but is guided above the sheet guide 34, and is bent. The sheet is discharged and stacked on the sheet stacking section 7 in the upper portion of the apparatus by the discharge roller 32 and the discharge roller 33 while changing the traveling direction along the line.

Since the notches 37, 38 are provided in a part of the guide rib 35, the contact between the sheet and the sheet guide surface 36 of the guide rib 35 is intermittent, and the sliding resistance is reduced. Even a sheet such as a sheet having a smooth surface and easily adhering to the sheet guide surface 36 can be smoothly conveyed.

The notch 36 of the guide rib 35,
As shown in FIG. 4, 37 may be adjacent guide ribs to shift the position in the sheet conveying direction. By doing so, the rear end of the sheet does not fall into a plurality of adjacent notches at the same time, and the effect of reducing the splash sound at the time of dropping is produced.

In the above example, the number of cutouts of each guide rib is two, but the number of cutouts may be one as shown in FIG. 4 or many as described later. (Second Embodiment) Next, an embodiment in which a part of the previous embodiment is changed will be described.

As shown in FIG. 5, a plurality of grooves 40 thinner than the thickness of the guide rib 35 are provided on each of the sheet guide surfaces 36 of the guide rib 35. Similarly to the notches 37 and 38 of the previous embodiment, the upstream side of the groove 40 is gently inclined so that the leading end of the sheet is not easily caught, and the grooves 40 are continuously arranged at predetermined intervals. I do.

With the above structure, the contact between the sheet and the sheet guide surface 36 is intermittent as in the previous embodiment, so that the sliding resistance is reduced, and the sheet does not adhere to the sheet guide surface 36 smoothly. Transport is possible.

(Third Embodiment) Next, an embodiment in which a part of the above embodiment is further modified will be described.

As shown in FIG. 6, a fine uneven pattern 50 having a grain shape is integrally formed on the surface of the sheet guide surface 36 of the guide rib 35. 50-100μ so that it does not get caught
m, and the tip of the projection has a spherical shape so that the sheet slides smoothly.

By configuring the sheet guide 35 in this manner, the sheet and the sheet guide surface 36 come into contact with each other on a fine uneven surface, so that they can be smoothly conveyed without being in close contact with each other.

(Fourth Embodiment) Next, another embodiment will be described with reference to FIGS. The same parts as those in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 7 and 8, a guide roller 60 is provided on the sheet guide 34. The center axis 61 of the guide roller 60 is rotatably supported at both ends by a main body (not shown). By providing an escape groove 63 in each guide rib 35, the center axis 61 is positioned inside the sheet guide surface 36. ing. A plurality of rollers 62 are fitted or formed integrally with the central shaft 61, and the outer edge of the rollers 62 is configured to project slightly inward from the sheet guide surface 36 of the guide rib 35.

The guide roller 60 is driven to rotate by the image-formed sheet being conveyed along the sheet guide surface 36 and coming into contact with the outer edge of the roller.

As described above, by providing the sheet guide 35 with the guide roller 60 that rotates following the sheet, the outer edge of the guide roller 60 becomes a part of the sheet guide surface, and the sheet is formed in the guide roller 60 and the vicinity thereof. Since there is no contact with the sheet guide surface 36 and the sliding resistance is reduced, it is possible to smoothly convey even a sheet having a smooth surface such as an OHP sheet and easily adhering to the rib surface.

In the illustrated example, the guide rollers 60 are provided below the sheet guide surface 36. However, the guide rollers 60 may be provided above this, or may be increased to two or more than one in the illustrated example.

[0040]

As described above, according to the present invention,
When an OHP sheet with a smooth surface or a sheet with an image formed on the back side is conveyed along a curved guide rib, the contact area between the sheet and the sheet guide surface decreases, and the contact becomes intermittent. Is difficult to adhere to the sheet guide surface, and the occurrence of sheet jam and abnormal sliding noise is prevented.

In addition, since the sheet guide surface is formed with fine irregularities, the sheet and the sheet guide surface are not in surface contact, and the sheet is less likely to be in close contact with the sheet guide surface, and sheet jams and abnormal sliding noise are generated. Is prevented.

Further, since the guide roller is a part of the sheet guide surface, the sheet does not slide between the sheet and the sheet guide surface at the guide roller portion, and sheet jam or abnormal sliding due to the sheet coming into close contact with the sheet guide surface. The generation of sound is prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sheet conveying apparatus according to a first embodiment of the present invention.

FIG. 2 is a front sectional view of the sheet conveying apparatus according to the first embodiment of the present invention.

FIG. 3 is a front sectional view of an image forming apparatus including the sheet conveying device according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a partially modified sheet conveying apparatus according to the first embodiment.

FIG. 5 is a perspective view of a guide sheet guide according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a guide sheet guide according to a third embodiment of the present invention.

FIG. 7 is a perspective view of a sheet conveying apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a front sectional view of a sheet conveying apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a front sectional view of a conventional image forming apparatus.

FIG. 10 is a perspective view of a conventional sheet conveying device.

FIG. 11 is a front sectional view of a conventional sheet conveying apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printer 2 ... Device main body 5 ... Image forming part 6 ... Sheet discharge part 30 ... Conveyance roller 32 ... Discharge roller 34 ... Sheet guide 35 ... Guide rib 36 ... Sheet guide surface 37, 38 ... Notch part 40 ... Groove 50 ... Unevenness Pattern 60: Guide roller 61: Shaft S: Sheet

Claims (6)

[Claims] A plurality of guide members provided integrally with a curved sheet guide surface; and a transport roller for guiding a sheet to the plurality of guide members, wherein a sheet transport direction of the transport roller is controlled by the plurality of guide members. A sheet conveying apparatus for conveying a sheet by inverting a sheet by a predetermined angle, wherein a notch portion is provided on a sheet guide surface of the guide member so that a sheet being conveyed is not in contact with the sheet. A plurality of guide members provided integrally with a curved sheet guide surface; and a transport roller for guiding a sheet to the plurality of guide members, wherein a sheet transport direction by the transport roller is controlled by the plurality of guide members. In a sheet conveying apparatus that conveys a sheet by being inverted by a predetermined angle, a fine uneven pattern is provided on the surface of the sheet guide surface of the guide member, and the height of the unevenness is 30 μm or more.
A sheet conveying device having a thickness of 0 μm or less. A plurality of guide members provided integrally with a curved sheet guide surface; and a transport roller for guiding a sheet to the plurality of guide members, wherein a sheet transport direction of the transport roller is controlled by the plurality of guide members. In a sheet conveyance device that performs sheet conveyance by inverting the sheet by a predetermined angle, a guide roller rotatable in a sheet conveyance direction is provided in the middle of a sheet passage area of the guide member, and a circumferential portion of the guide roller has the guide surface. A sheet conveyance device configured to protrude inward in a more curved direction and to be a part of a sheet guide surface. 4. Each of the guide members is formed of a plate-like member, and a curved sheet guide surface of a plurality of guide members arranged in parallel forms a plane perpendicular to a sheet conveying direction. Item 4. The sheet conveying device according to any one of Items 1 to 3. 5. The conveyance roller is provided below a guide member, and a sheet conveyed by the conveyance roller is
4. The sheet conveying device according to claim 1, wherein the sheet is inverted by a predetermined angle while being guided upward from below the sheet guide surface of the guide member. 6. An image forming apparatus comprising: the sheet conveying device according to claim 1; and an image forming unit that forms an image on a sheet.