JPH11349181A - Paper sheet carrier device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suck and carry paper sheets of any size in a stable state without changing suction force generated in a through hole due to the size of the sheets to carry. SOLUTION: A paper sheet carrier device 14 is constituted by providing a plural number of through holes 23 on a carrier belt 22 suspended on a driving roller 20 and a driven roller 21 and providing fitting projections 24 to fit in these through holes 23 on the driving roller 20. A diameter of the driving roller 20 is formed larger than a diameter of the driven roller 21, and a sheet carrier roller is provided at a position facing against the driving roller 20 through a sheet carrier route. Suction force is generated when the fitting projections 24 come out of the through holes 23, and the sheets are sucked by this suction force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to two rollers,
The present invention relates to a paper transport device provided with a transport belt stretched by the rollers and transporting the paper on the paper mounting portion by suction.

[0002]

2. Description of the Related Art Conventionally, as a paper transporting device for transporting a paper by sucking it under a negative pressure, a paper transporting device having an endless transporting belt stretched over two rollers is known. A plurality of through holes are evenly formed in the whole, and a suction duct is provided between both rollers and the conveyor belt to suck air from the through holes, and the air is sucked through the suction duct. Suction fan was provided.
The suction fan sucks air in the vicinity thereof from the through hole of the conveyor belt, sucks the sheet to the conveyor belt, and conveys the sheet in a state where the sheet is sucked, that is, in a state where the sheet is sucked.

[0003] Japanese Unexamined Patent Publication No. 1-104560 discloses an apparatus based on the paper transport apparatus having such a structure.

The device disclosed in Japanese Patent Application Laid-Open No. 1-104560 controls the suction force of a suction fan in accordance with the size and quality of the paper. The number of rotations of the suction fan is changed, and the suction force is increased when small-sized paper is conveyed.

In Japanese Patent Application Laid-Open No. Hei 5-278894, the suction duct is divided into a small portion on the upstream side and a large portion on the downstream side in the paper transport direction, and a separate suction fan is provided for each portion. Is provided, it is possible to increase the suction force on the upstream side by such a configuration, even if the conveyed paper is curled,
This enabled stable transport of paper.

Japanese Unexamined Patent Application Publication No. 9-150987 has a position detecting means for detecting a position of a conveying belt and a sheet to be conveyed, and a position detecting means for detecting a position of a sheet conveyed through a through hole of the conveying belt. When the paper is placed on the area where the through-hole is formed, the position detecting means detects that the sheet is in a transport state requiring a suction force, and increases the suction force of the suction fan. As a result, the paper can be stably conveyed.

[0007] Japanese Patent Application Laid-Open No. Hei 5-278281 discloses a method for adsorbing paper without using a transport belt. In Japanese Patent Application Laid-Open No. 5-278281, a gap is provided between a paper feed roller and a platen, and a concave groove is provided on the outer periphery of the paper feed roller.
When the paper passes over the paper feed roller, the chamber formed at the lower part of the platen and the suction fan provided at the lower part of the chamber are driven to drive the paper to the platen through the gap between the paper feed roller and the platen and the groove of the paper feed roller. The paper has been sucked and conveyed.

[0008]

In the apparatus using the transport belt as described above, the sheet is sucked and transported by sucking the air on the front side of the transport belt from the through hole. Therefore, a suction fan for suction is required, which increases the size of the paper transport device, generates noise when air is taken in and exhausted, and if the paper size is different, especially if the paper size is small, the paper position Since the air flows in from a portion where the air resistance is not provided, that is, a portion where there is no air resistance, the suction force becomes insufficient for a small-sized sheet, and there is a possibility that conveyance failure may occur.

In Japanese Unexamined Patent Publication No. 1-104560 and Japanese Unexamined Patent Publication No. 5-278894, a plurality of suction fans are provided. In the case of transporting a sheet, since air flows in from a portion where the sheet is not located, that is, a portion where there is no air resistance, suction force is insufficient for a small-sized sheet, and there is a possibility that a transport failure may occur. .

In the device disclosed in Japanese Patent Application Laid-Open No. 9-150987, it is necessary to provide a through hole in accordance with the sheet positioned on the conveying belt, and the size of the sheet to be conveyed is limited.
There is a problem that paper of various sizes cannot be conveyed.

In Japanese Patent Application Laid-Open No. Hei 5-278281, a suction fan for suction is required, and the size of the paper transport device is increased, and the leading end or the trailing end of the paper is placed in the gap between the paper feed roller and the platen. At this time, if suction by the suction fan is performed, the paper is drawn into the chamber, and there is a problem that the paper may be wrapped around the paper feed roller to cause a jam.

The paper transport apparatus of the present invention has been made in view of the above problems, and has a through hole formed in a transport belt, and a fitting protrusion fitted in the through hole is formed on a roller for stretching the transport belt. It is an object of the present invention to adsorb and convey a sheet by a suction force generated when a fitting protrusion of the roller comes out of a through hole of a conveyance belt, thereby enabling adsorption and conveyance of a sheet without a suction fan. Things.

[0013]

According to a first aspect of the present invention, there is provided a sheet transport apparatus, comprising: two rollers; a roller stretched by the rollers; A plurality of through-holes are provided in the conveyor belt, and a roller closer to the paper mounting portion of the two rollers is formed to have a diameter larger than that of the other roller. A fitting projection for fitting is formed.

According to a second aspect of the present invention, there is provided a sheet transport apparatus including two rollers, and a transport belt stretched by the rollers and sucking and transporting the sheet on the sheet placement unit, and a plurality of through holes are formed in the transport belt. An inner belt stretched by two rollers having a shorter overall length than the transport belt is provided inside the transport belt, and a fitting protrusion that fits into a through hole of the transport belt is provided on a surface of the inner belt. Has formed.

According to a third aspect of the present invention, the through hole is formed except for both ends in the width direction of the conveyor belt.

According to a fourth aspect of the present invention, there is provided a sheet conveying apparatus, wherein a band region in which the through-hole is not formed is formed in the conveying direction of the conveying belt, and the belt region comes into contact with the band region of the conveying belt from the front side of the conveying belt. A contact roller is provided.

According to a fifth aspect of the present invention, in the paper transport apparatus, the two rollers are formed to have the same diameter, and both rollers are provided with fitting projections.
Two separation rollers are provided between the two rollers to contact the surface of the conveyance belt and press the conveyance belt inward to separate the conveyance belt from the sheet conveyance path. The developer image of the image forming unit of the image forming apparatus is provided between the separation rollers. A transfer device for transferring to paper is provided.

According to a sixth aspect of the present invention, there is provided a sheet transporting apparatus comprising two rollers, and a transport belt stretched by the rollers and sucking and transporting the sheet on the sheet receiving portion, wherein the transport belt has a plurality of bottomed holes. And a magnet is provided at the bottom of the bottomed hole, and an electromagnet for attracting the magnet at the bottom of the bottomed hole is provided inside the conveyor belt.

According to a seventh aspect of the present invention, the magnetic force of the electromagnet is controlled by the type of the sheet to be transported.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrophotographic copying machine using a paper conveying apparatus according to the present invention will be described with reference to FIG.

In the electrophotographic copying machine of the present invention, a document table 2 on which a document is placed is provided on an upper surface of a copying machine body 1, and a document reading section is provided above the copying machine body 1 and below the document table 2. An image forming unit as an image forming unit is provided below the document reading unit.

The original reading section comprises a light source 3 for irradiating the original with light, and reflection mirrors 5 and 6 for reflecting and reflecting the reflected light from the original to a photosensitive drum 4 of an image forming section described later. ing.

The image forming section is formed by irradiating the photosensitive drum 4, a charger 7 for uniformly charging the surface of the photosensitive drum 4, and reflecting light from the reflecting mirror 6 to the charged photosensitive drum 4. A developing unit 8 for developing the formed electrostatic latent image with toner to form a toner image, a transfer unit 9 for transferring the toner image on the photosensitive drum 4 to paper, and a static eliminator 10 for removing the potential of the photosensitive drum 4 It is composed of

A paper cassette 11 for accommodating paper P is provided on the side of the copying machine main body 1.
A pickup roller 12 for picking up the sheets one by one is provided, a pair of sheet conveyance rollers 13 is provided downstream of the pickup roller 12 in the sheet conveyance direction, and the sheet conveyance rollers 13 are transferred to a transfer portion where the toner image is transferred by the transfer device 9. A paper transport device 14 for sucking and transporting the paper transported by the printer, a pair of transport rollers 15 provided downstream of the transfer unit,
A fixing roller 16 for fixing the toner image transferred to the sheet is provided downstream of the conveying roller 15 and a pair of conveying rollers 17 are provided. A pair of discharge rollers 18 for discharging the sheet P after fixing is provided. An output tray 19 for stacking the stacked sheets P is provided.

FIG. 2 shows the first embodiment of the paper transport device 14.
4 to FIG. 4, the paper transport device 14 is provided with a drive roller 2 located below the transport path as shown in FIG.
A plurality of through-holes 23 are provided in the transport belt 22 stretched over the driven roller 21 and the driven roller 21. The drive roller 20 is provided on the upstream side in the sheet transport direction, and the diameter of the drive roller 20 is formed to be larger than the diameter of the driven roller 21, and is located at a position facing the drive roller 20 via the sheet transport path. A paper transport roller 25 is provided.

The operation of the above configuration will be described. When the leading end of the paper P picked up by the pickup roller 12 from the paper feed cassette 11 reaches the paper transport device 14,
The paper P is attracted to the transport belt 22 of the paper transport device 14 and transported to the transfer unit.

At this time, the drive roller 20 is set at the position a in FIG.
Is fitted into the through-hole 23 of the conveyor belt 22, and this state is continued up to the position b. At the position c, the fitting protrusion 24 comes out of the through-hole 23, so that a suction force is generated and the paper P is removed. Adsorb.

That is, as shown in FIG. 4, the fitting projection 24a of the driving roller 20 is fitted to the innermost part of the through hole 23 of the conveyor belt 22, and the driving roller 20 rotates to the left in the figure by rotation of the driving roller 20. 20 and the conveyor belt 22 move,
It starts to get out of the through hole 23 as shown by the fitting projection 24b, and comes out of the through hole 23 as shown by the fitting projection 24c. When the fitting protrusion 24b comes out of the through-hole 23 in this manner, the air on the surface side (paper P side) of the through-hole 23 is sucked into the through-hole 23, and the suction force on the surface side of the through-hole 23. Then, the sheet P is sucked by the suction force and is conveyed to the transfer section.

At this time, since the suction force is generated in each through-hole 23, the suction force generated in the through-hole 23 does not vary depending on the size of the paper P to be conveyed, and the paper P of any size is stable. In this state, it can be conveyed by suction.

FIG. 5 shows a second embodiment of the paper conveying apparatus of the present invention.
In other words, the through holes 23 are provided only in the area A except for the areas B1 and B2 at both ends of the conveyor belt 22 in the sheet conveying direction. At this time, the width of the area A of the transport belt 22 is formed to be the same as the maximum width of the transport paper, and the areas B1 and B2 are formed on both sides of the area A. An area C in which the fitting projections 24 are not formed on both sides of the drive roller 23 facing the areas B1 and B2 of the transport belt 22.
Is formed.

With such a configuration, the transport belt 22 has no through-holes 23 at both ends (regions B1 and B2). Therefore, by increasing the mechanical strength of both ends, consequently, The mechanical strength of the transport belt 22 can be increased.

FIG. 6 shows a third embodiment of the sheet conveying apparatus of the present invention.
To be more specific, the areas D1, E, and B between the areas B1 and A excluding the areas B1 and B2 at both ends of the conveyor belt 22 in the sheet conveyance direction and the area E at the center are described.
2, a through-hole 23 is provided in a portion of a region D2.
At this time, the width of the areas D1 and D2 of the transport belt 22 is formed to be the same as the maximum width of the transport paper, and the areas B1 and B2 are formed on both sides of the areas D1 and D2. Then, the driving roller 2 facing the areas B1, B2, and E of the transport belt 22
A region C in which the fitting protrusion 24 is not formed is formed on both sides and a center of 3.

Further, the conveying belt 22 is moved from the center of the conveying belt 22 in the conveying direction to the driven roller 21 side.
The belt is brought into contact with the surfaces B1, B2, E of
2, a paper pressing roller 26 is provided, and the paper pressing roller 26 is rotatably supported by a rotating shaft 27.

By adopting such a configuration, the transport belt 22 has both end portions and a central portion (regions B1, B2, E).
Since the through-holes 23 are not formed, the mechanical strength of the conveyor belt 22 can be increased by increasing the mechanical strength at both end portions and the central portion.
Since the paper P is pressed by the paper pressing roller 26, the adhesion between the transport belt 22 and the paper P can be further ensured, and the paper P can be transported in a more stable state.

FIG. 7 shows a fourth embodiment of the sheet conveying apparatus of the present invention.
8, the inner belt 29 is provided on the inner side of the transport belt 22 by being stretched between the driving roller 20 and the second driven roller 27 provided on the inner side of the transport belt 22. Side (conveyor belt 22
On the side), a fitting protrusion 30 that fits into the through hole 23 of the conveyor belt 22 is provided.

At this time, the driving roller 20 and the driven roller 21
Are formed to have the same diameter, and only the diameter of the second driven roller 28 is made smaller than the diameters of the other rollers.
Can escape (disengage).

By adopting such a configuration, the position at which the fitting projection 30 is separated from the through hole 23 (position at which the protrusion is started) and the completely separated position (the position at which the fitting protrusion 30 is completely removed).
, The suction force on the sheet P can be applied in a wide (long) working range, and the conveyance state of the sheet P can be stabilized.

FIG. 9 shows a fifth embodiment of the sheet conveying apparatus of the present invention.
To be more specific, a second drive roller 31 provided with a fitting protrusion having the same diameter as the drive roller 20 is provided downstream of the transfer device 9 in the paper transport direction, and is driven by the second drive roller 31 downstream of the paper transport direction. A roller 21 is provided, and the respective drive shafts of the drive roller 20 and the second drive roller 31 are connected by a drive belt 32 so that both rollers are interlocked.

Separation rollers 33 and 34 are provided on the upstream side and the downstream side of the transfer unit 9 in the sheet conveyance direction to contact the front side of the conveyance belt 22 to separate the conveyance belt 22 from the transfer unit 9.
Is provided.

With such a configuration, the fitting protrusions of the drive roller 20 and the second drive roller 31 are moved from the through-hole of the transport belt 22 at two locations on the upstream side and the downstream side of the transfer unit 9 in the paper transport direction. By adsorbing and transporting the paper P to the transport belt 22 with the suction force generated by the detachment, the toner image is not transferred onto the transport belt 22 by pressurization or heating on the transport belt 22, and the transfer of the toner image on the transport belt 22 is not performed. The deformation of the conveyor belt 22 (through-hole 23) due to pressure or heat can be prevented, and the deformation of the conveyor belt 22 (through-hole 23) lowers the suction force due to lower fitting accuracy between the through-hole 23 and the fitting protrusion. Can be prevented, and the paper P can be transported in a stable state.

Embodiment 6 of the sheet transporting apparatus of the present invention is shown in FIG.
11 and FIG. 11, the conveyor belt 22 is provided with a plurality of bottomed holes 35, and a magnet 3 is provided at the bottom of the bottomed hole 35.
6, an electromagnet 37 is disposed inside the conveyor belt 22, and a sheet pressing roller 25 that opposes the conveyor belt 22 via a sheet conveyance path and presses the sheet P against the conveyor belt 22.
Is provided. The drive roller 20 on which the transport belt 22 is stretched has no fitting projection.

With this configuration, the magnet provided in the bottomed hole 35 of the conveyor belt 22 is attracted toward the electromagnet 37 by the magnetic force of the electromagnet 37, and
2 is attracted to the electromagnet 37 side, so that a negative pressure is generated on the sheet P side, and the sheet P is attracted by the negative pressure.

At this time, the amount of power to the electromagnet 37 is controlled according to the type of the paper P to be conveyed, and the magnetic force of the electromagnet 37 is controlled, so that the force of the conveyor belt 22 attracted to the electromagnet 37 is controlled. By changing the negative pressure generated on the side of the paper P of the belt 22 in accordance with the type of the paper P, the paper P is stably maintained regardless of the type of the paper P.
Can be transported.

[0044]

According to the paper conveying apparatus of the first aspect,
When the fitting protrusion of the drive roller comes out of the through hole of the conveyor belt, the air on the surface side (paper side) of the through hole is moved into the inside of the through hole, and a suction force is generated on the surface side of the through hole. The paper is attracted by this suction force. As described above, since the suction force generated at this time is generated in the individual through-holes, the suction force generated in the through-hole does not differ depending on the size of the sheet to be conveyed, and stable regardless of the size of the sheet. It can be sucked and transported in the state. Further, since there is no need to provide a separate member for sucking the paper, the paper transport device can be downsized.

According to the second aspect of the present invention, since the inner belt is provided with the fitting projection which fits into the through-hole of the transport belt, the detachment start position of the fitting projection from the through-hole (the position at which the fitting projection comes out) is determined. The distance between the start position) and the completely detached position (the position where the sheet completely exits) can be increased, and a suction force can be applied to the sheet P in a wide (long) working range, so that the sheet conveyance state can be stabilized. Can be done.

According to the third aspect of the present invention, since the through holes are formed except for both ends of the conveyor belt,
By increasing the mechanical strength at both ends, the mechanical strength of the transport belt can be increased as a result.

According to the paper transport apparatus of the fourth aspect, by providing a belt area in which a through hole is not formed in the transport direction of the transport belt and providing a contact roller in contact with the belt area, The mechanical strength of the transport belt can be increased, and the paper can be pressed by the contact roller to ensure the adhesion between the transport belt and the paper, and the paper can be transported in a more stable state. be able to.

According to the fifth aspect of the present invention, two protrusions having the same diameter are provided on the two rollers of the same diameter which stretch the transport belt, and the transport belt is brought into contact with the front side of the transport belt so that the transport belt is moved. By providing a separation roller that separates the transfer roller from the transfer roller, and by providing a transfer unit of the image forming unit between the separation rollers, the sheet can be suctioned at two locations on the upstream side and the downstream side in the sheet conveyance direction of the transfer unit. The paper can be transported in a stable state, and the transfer of the developer image to the paper by pressing or heating is not performed on the transport belt. Can be prevented, and a decrease in suction force due to a decrease in fitting accuracy between the through hole and the fitting projection due to deformation of the transport belt can be prevented,
Paper can be transported in a stable state.

According to the paper conveying apparatus of the present invention, the magnet provided at the bottom of the bottomed hole of the conveying belt is attracted by the electromagnet to generate the attraction force for adsorbing the paper. Wear due to fitting and disengagement of the hole and the fitting projection can be eliminated, and a decrease in suction performance due to wear can be prevented.

According to the sheet conveying apparatus of the present invention, the magnetic force of the electromagnet is controlled according to the type of the sheet to be conveyed, so that the attraction force generated on the sheet side of the conveying belt is changed according to the type of the sheet. Therefore, the paper can be transported in a stable state regardless of the type of the paper.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electrophotographic copying machine using a sheet conveying device of the present invention.

FIG. 2 is a perspective view showing Embodiment 1 of the sheet conveying device of the present invention.

FIG. 3 is a sectional view of FIG. 2;

FIG. 4 is an enlarged sectional view of a main part of FIG. 2;

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

FIG. 6 is a perspective view illustrating a third embodiment of the paper transport apparatus of the present invention.

FIG. 7 is a cross-sectional view of Embodiment 4 of the sheet conveying device of the present invention.

FIG. 8 is an enlarged view of a main part of FIG. 7;

FIG. 9 is a cross-sectional view of Embodiment 5 of the sheet conveying device of the present invention.

FIG. 10 is a cross-sectional view of Embodiment 6 of the sheet conveying device of the present invention.

FIG. 11 is an enlarged view of a main part of FIG. 10;

[Explanation of symbols]

 14 20 Drive roller 21 Follower roller 22 Conveyor belt 23 Through hole 24 Fitting protrusion

Claims (7)

[Claims] 1. A paper transport device comprising: two rollers; and a transport belt stretched by the rollers and transporting a sheet on a sheet placement unit by suction, wherein a plurality of through holes are provided in the transport belt; A sheet conveying device, wherein a roller closer to a sheet mounting portion of two rollers is formed to have a diameter larger than that of the other roller, and a fitting protrusion is formed on a peripheral surface thereof so as to fit into the through hole. 2. A paper transport device comprising two rollers and a transport belt stretched by said rollers and sucking and transporting a sheet on a paper placement unit, wherein said transport belt is provided with a plurality of through holes, An inner belt stretched by two rollers having a shorter overall length than the conveyor belt is provided inside the conveyor belt, and a fitting projection is formed on a surface of the inner belt to fit into a through hole of the conveyor belt. A paper transport device characterized by the above-mentioned. 3. The sheet conveying device according to claim 1, wherein the through holes are formed except for both end portions in a width direction of the conveying belt. 4. A belt region in which the through-hole is not formed in the transport direction of the transport belt, and a contact roller that contacts the belt region of the transport belt from the front side of the transport belt is provided. 3. The sheet transport device according to claim 1, wherein 5. The two rollers are formed to have the same diameter, fitting projections are provided on both rollers, the two rollers are brought into contact with the surface of a transport belt, press the transport belt inward, and separate from the paper transport path. 2. The sheet conveying device according to claim 1, wherein two separating rollers are provided, and a transfer device for transferring a developer image of an image forming unit of the image forming apparatus to a sheet is provided between the separating rollers. 6. A paper transport device comprising two rollers and a transport belt stretched by said rollers and sucking and transporting a sheet on a paper placing section, wherein said transport belt is provided with a plurality of bottomed holes, A sheet conveying device, wherein a magnet is provided at the bottom of the bottomed hole, and an electromagnet for attracting the magnet at the bottom of the bottomed hole is provided inside the conveyor belt. 7. The sheet conveying apparatus according to claim 5, wherein the magnetic force of the electromagnet is controlled according to the type of the sheet to be conveyed.