JP4098125B2 - Paper transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet conveying device in an image forming apparatus such as a copying machine and a facsimile, and more particularly to noise prevention during sheet conveyance.
[0002]
[Prior art]
In recent years, there has been a strong demand for miniaturization of OA equipment, and it has been forced to arrange components so that a dead space is not formed inside the casing, and the paper conveyance path is often curved. On the other hand, the paper has a certain level of waist strength, and even when bent by a curved conveyance path, it tends to stretch due to its waist strength. As a result, there is a problem in that noise is generated at this time when the trailing edge of the sheet jumps and strikes the guide plate forming the conveying path at the moment when the trailing edge of the sheet comes off the conveying roller.
[0003]
As a noise countermeasure at the time of paper feeding, the first conventional technique sends the paper in the paper feeding cassette to a conveyance path curved in a U shape by a paper feeding roller, and delivers it to the registration roller. Then, the rear end of the paper removed from the paper feed roller is supported by a rotating body so that the rear end of the paper removed from the paper feed roller does not suddenly fall and hit the transport path (Patent Document). 1).
[0004]
The second prior art is a sheet conveying device that guides a sheet fed from a sheet feeding cassette by a sheet feeding roller by bending the sheet toward a registration roller by a curved guide member. A flat guide surface that slopes downward toward the upstream side of the paper is formed, and the rear end of the paper that has been removed from the paper cassette is collided with this wide flat guide surface. At this time, air is cushioned to generate noise. (Patent Document 2).
[0005]
In the third prior art, when a sheet fed from a sheet feeding cassette is guided to a registration roller by a curved conveyance path, an elastic thin plate is provided near the upstream side of the registration roller, and this elastic thin plate is brought into contact with the sheet. The leading edge of the paper is intended to be aligned with the nip portion of the registration roller while being bent more elastically (Patent Document 3).
[0006]
Further, according to the fourth prior art, when the sheet fed from the sheet feeding cassette is guided downstream by a curved conveyance path, the bending sheet and the leading end of the elastic thin plate are formed into a convex or concave shape to thereby reduce the noise of the sheet conveyance. (Patent Document 4).
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-255834 [Patent Document 2]
Japanese Patent Laid-Open No. 10-35946 [Patent Document 3]
JP-A-8-26526 [Patent Document 4]
JP 2000-355441 A
[Problems to be solved by the invention]
However, the first prior art described above cannot be effective unless the outer diameter of the rotating body that supports the trailing edge of the paper is increased to a certain extent, and increasing the outer diameter of the rotating body is a space for component placement. There was a limit from the point of view.
[0009]
Further, the second prior art has a problem that it is contrary to the demand for miniaturization because the effect cannot be expected unless the area of the plane guide surface supporting the trailing edge of the paper is increased to a certain extent.
[0010]
The elastic thin plate shown in the third prior art cannot be expected to prevent the occurrence of noise caused by the trailing edge of the paper that has come off the transport roller.
[0011]
The fourth prior art can absorb noise from the elastic member, but it is difficult to eliminate the step in the vicinity of the bonded portion between the elastic member and the curved guide plate. The bonded portion of the curved guide plate configured as described above has to have an acute angle, and there is a possibility that the curved guide plate may be lost during parts transportation or assembly. Moreover, since it has a sharp blade shape at the time of assembly, it is quite dangerous. Even in the case of a metal such as a sheet metal, the thickness of the sheet metal plate or the R portion at the tip is always required, and a step difference between the elastic member and the curved guide plate is necessarily generated. Then, a paper jumping sound is generated at the level difference of the bonded portion, and it cannot be said that it is complete.
[0012]
The same applies to the case where an elastic member is bonded to the paper guide plate upstream of the curved guide plate.
[0013]
An object of the present invention is to suppress the generation of noise caused by the trailing edge of a sheet passing through a curved conveyance path jumping up.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, a curved conveyance path that guides a sheet to be conveyed, a first sheet guide plate that is provided substantially in parallel so as to sandwich the sheet in the conveyance path, and a change in the conveyance direction of the sheet a second paper guide plate provided at a position, and the conveying direction leading the conveying direction trailing end to the first sheet guide plate is fixed is located in the conveying path, first it is in contact with the second paper guide plate A sheet conveying apparatus comprising: an elastic member; and a second elastic member having a conveyance direction rear end fixed to a second sheet guide plate and a conveyance direction front end positioned in the conveyance path. The front end in the transport direction of the plate is characterized in that the central portion in the transport path width direction is recessed with respect to the transport direction from both ends.
[0015]
According to the first aspect of the present invention, the fed paper is curved and conveyed by the curved conveyance path. An elastic member is fixed to the paper guide plate provided in the conveyance path. When the rear end of the paper comes off the paper guide plate, the elastic member is stretched by the strength of its own waist and presses the elastic member. At this time, since the central portion in the transport path width direction of the front end of the paper guide plate is recessed from the end portion, the center in the paper width direction is the earliest when the rear end of the paper leaves the paper guide plate. The sheet is pressed against the elastic member, and the sheet is pressed against the elastic member from the center in the width direction of the sheet toward the end in a manner that follows the pressure. In this way, since the paper gradually comes into pressure contact with the elastic member from the center in the width direction of the paper to the edge portion, the rear end of the paper jumps up at a stretch and does not hit the elastic member, and the paper jumps and is elastic. Energy generated when hitting the member can be attenuated more effectively. Therefore, it is possible to reduce the noise generated when the paper is bounced and hit.
[0016]
Invention according to claim 2, a conveying path curved to guide the sheet conveyed, a first paper guide plate arranged substantially parallel so as to sandwich the sheet in the conveying path, changing the conveying direction of the sheet a second paper guide plate provided at a position, and the conveying direction leading the conveying direction trailing end to the first sheet guide plate is fixed is located in the conveying path, first it is in contact with the second paper guide plate A sheet conveying apparatus comprising: an elastic member; and a second elastic member having a conveyance direction rear end fixed to a second sheet guide plate and a conveyance direction front end positioned in the conveyance path. The front end of the plate in the transport direction is characterized in that the central portion in the transport path width direction protrudes in the transport direction from both ends.
[0017]
In the second aspect of the present invention, the front end of the paper guide plate in the transport direction protrudes from the end in the transport path width direction, so that when the rear end of the paper leaves the paper guide plate, The end of the sheet in the width direction presses against the elastic member earliest, and the sheet presses against the elastic member from the end of the sheet toward the center so as to follow the end. As described above, since the sheet gradually comes into pressure contact with the elastic member from the end in the width direction of the sheet toward the center, the same effect as that of the first aspect of the invention can be obtained.
[0018]
According to a third aspect of the present invention, there is provided a curved conveyance path that guides a sheet to be conveyed, a first sheet guide plate that is provided substantially in parallel so as to sandwich the sheet in the conveyance path, and a change in the conveyance direction of the sheet. a second paper guide plate provided at a position, and the conveying direction leading the conveying direction trailing end to the first sheet guide plate is fixed is located in the conveying path, first it is in contact with the second paper guide plate A sheet conveying apparatus comprising: an elastic member; and a second elastic member having a conveyance direction rear end fixed to a second sheet guide plate and a conveyance direction front end positioned in the conveyance path. The front end of the plate in the transport direction is formed obliquely with respect to the line in the width direction of the transport path and perpendicular to the transport direction.
[0019]
In the third aspect of the invention, when the trailing edge of the paper leaves the paper guide plate, a part in the paper width direction presses the elastic member earliest, and the whole paper gradually presses the elastic member. The effect similar to that of the first aspect of the invention is achieved.
Further, as in the invention according to claim 4, in the paper transport device according to any one of claims 1 to 3, the leading end in the transport direction of the first paper guide plate is a curved transport path through which the paper is guided. The second paper guide plate is provided in the vicinity of the curved top portion of the curved conveyance path.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0021]
1 is an enlarged perspective view showing a portion (a) of FIG. 5, FIG. 2 is a sectional view around the curved guide plate of FIG. 1, and FIG. 3 is an enlarged perspective view showing a portion (b) of FIG. 4 is a cross-sectional view showing the conveyance guide plate of FIG. 3, FIG. 5 is a view showing a curved conveyance path, and FIG. 6 is a cross-sectional view schematically showing the entire image forming apparatus according to the first embodiment of the present invention. It is.
[0022]
As shown in FIG. 6, the paper transport apparatus 1 according to the first embodiment is applied to a tandem type color printer 100, and the color printer 100 includes a paper feed unit 3 that stores paper P, The image forming unit 5 for forming an image, the electrostatic latent image formed on the image carrier (photosensitive member) 13 is visualized, the transfer body 7 for sequentially transferring the visible image, and the sheet P is heated. And a fixing device 9 that performs pressurization, a paper discharge unit 11 that discharges the paper P after fixing, and the like.
[0023]
The image forming unit 5 is charged on the photosensitive member 13 by a charger, and the charged portion of the photosensitive member 13 is irradiated with light by the optical writing unit 10 to form an electrostatic latent image. To form a desired color (black, yellow, magenta, cyan) on the transfer body 7. The developed image is transferred to the paper P conveyed to the image forming unit 5, and then the unfixed image is fixed by the fixing device 9, and then conveyed to the paper discharge unit 11 and discharged outside the apparatus.
[0024]
The paper feed unit 3 includes two-stage paper feed trays 4 and 6 that can be pulled out. A pickup roller 21 that feeds the uppermost paper and a paper P that is sent out are formed above the paper feed trays 4 and 6. A paper feed roller 23 that feeds the paper toward the image unit 5 and a transport roller such as a grip roller 25 for turning the paper P upward are provided.
[0025]
A curved conveyance path 20 is provided between the paper feed roller 23 and the registration roller 17 located in front of the image forming unit 5, and guides the paper P to the registration roller 17.
[0026]
The curved conveyance path 20 includes a conveyance guide plate (paper P guide plate) 27 provided substantially parallel to sandwich the paper P, and a curved guide plate (paper guide plate) provided at a change position in the conveyance direction of the paper P. 29.
[0027]
A plate-like elastic member 33 such as polyethylene terephthalate is fixed to the leading end position in the transport direction of the transport guide plate 27, and the tip is in contact with the curved guide plate 29. Further, a step is formed between the leading end 28 of the transport guide plate 27 in the transport direction and the elastic member 33. When the rear end of the paper P passes through the step, the step of FIG. As shown by the alternate long and short dash line, it rebounds and comes into contact with the elastic member 33, and an impact sound is generated at this time. In the present embodiment, even if there is such a step, no impact sound is generated. That is, the conveyance direction front end 28 of the conveyance guide plate 27 is formed in a V shape such that the central portion in the conveyance path width direction is recessed with respect to the conveyance direction rather than the end portion.
[0028]
Further, the elastic member 31 similar to that attached to the conveyance guide plate 27 described above is fixed to the curved guide plate 29, and the tip thereof is located in the conveyance path. And the conveyance direction front-end | tip 30 of the curved guide plate 29 is formed in V shape that a center part is dented with respect to a conveyance direction rather than an edge part.
[0029]
Next, the operation of the present embodiment will be described based on the configuration described above. The paper P drawn from the paper feed tray 6 by the pickup roller 21 passes through the paper feed roller 23 and is guided into the curved conveyance path 20. The paper P guided into the curved conveyance path 20 is conveyed along the conveyance guide plate 27. Then, the sheet P is conveyed along the curved surface of the curved guide plate 29, the sheet P is guided to Regis Toro over La 17 direction.
[0030]
Here, when the trailing edge of the sheet P comes out of the conveyance guide plate 27 when the trailing edge of the sheet P comes to the stepped portion between the conveyance guide plate 27 and the elastic member 33, the sheet P is stretched by the strength of its own waist. The elastic member 33 is pressed. At this time, the conveyance direction front end 28 of the conveyance guide plate 27 has a center portion in the conveyance path width direction that is recessed from both ends, so that when the rear end of the sheet P leaves the conveyance guide plate 27, The center presses the elastic member 33 earliest, and the paper P presses the elastic member 33 from the center in the width direction of the paper P toward the end in a form following the press. In this way, since the paper P gradually comes into pressure contact with the elastic member 33 from the center in the width direction of the paper P toward the end portion, the rear end of the paper P jumps up at a stroke and does not hit the elastic member 33. The energy generated when the paper P bounces and hits the elastic member 33 can be attenuated more effectively. Accordingly, it is possible to reduce noise generated when the paper P hits the elastic member 33.
[0031]
Further, when the rear end of the paper P comes out of the curved guide plate 29 when the rear end of the paper P comes to the stepped portion between the curved guide plate 29 and the elastic member 31, it is stretched by the strength of its own waist and elastic. The member 31 is pressed. At this time, the leading end 30 in the conveyance direction of the curved guide plate 29 has a central portion in the conveyance path width direction that is recessed from the end, so that the trailing edge of the sheet P leaves the curved guide plate 29 as described above. In addition, the noise generated when the paper P hits the elastic member 31 can be reduced.
[0032]
Next, other embodiments will be described. In the description, parts having the same functions and effects as those described above are denoted by the same reference numerals, and detailed description thereof is omitted. In the second embodiment, the conveyance direction front end 28 of the conveyance guide plate 27 is formed in an inverted V shape so that the center in the conveyance path width direction protrudes from the end. In this case, when the rear end of the paper P leaves the conveyance guide plate 27, the end in the paper width direction comes into contact with the elastic member 33 earliest and follows the direction from the end of the paper P toward the center. P is in pressure contact with the elastic member 33. As described above, since the paper P gradually comes into pressure contact with the elastic member 33 from the end in the width direction of the paper P toward the center, noise generated when the paper P hits the elastic member 33 can be reduced.
[0033]
Similarly, the conveyance direction front end 30 of the curved guide plate 29 is also formed in an inverted V shape so that the center in the conveyance path width direction protrudes from the end. Also in this case, the noise generated when the paper P hits the elastic member 31 can be reduced.
[0034]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. In the above-described embodiment, the conveyance direction distal ends 28 and 30 of the conveyance guide plate 27 or the curved guide plate 29 are recessed in a V shape or projecting in an inverted V shape in the width direction of the conveyance path. However, the present invention is not limited thereto, and an arcuate recess or protrusion may be formed as shown in FIG. 9 or FIG. Moreover, the conveyance direction front ends 28 and 30 of the conveyance guide plate 27 or the curved guide plate 29 are linear or curved from one end in the conveyance path width direction to the other end as shown in FIGS. You may incline and form.
[0035]
In the above-described embodiment, the color image forming apparatus has been described. However, a monochrome image forming apparatus, a printer, a FAX, or the like may be used.
[0036]
【The invention's effect】
In the invention according to claim 1, since the paper gradually presses against the elastic member from the center in the width direction of the paper toward the edge portion, the rear end of the paper jumps up at a stretch and does not hit the elastic member. The energy generated when the paper bounces and hits the elastic member can be more effectively attenuated, and the noise generated when the paper bounces and hits can be reduced.
[0037]
According to the second aspect of the invention, since the paper gradually presses against the elastic member from the end in the width direction of the paper toward the center, the same effect as that of the first aspect of the invention can be achieved.
[0038]
In the invention according to claim 3, since the leading end of the paper guide plate in the transport direction is formed in an oblique direction with respect to the transport path width direction, when the rear end of the paper leaves the paper guide plate, the paper width direction Since a part of the sheet is pressed into contact with the elastic member earliest and the whole sheet is gradually pressed into contact with the elastic member, the same effect as that of the invention of claim 1 can be obtained.
[Brief description of the drawings]
FIG. 1 is an enlarged perspective view showing a portion (a) of FIG.
FIG. 2 is a cross-sectional view around the curved guide plate of FIG.
3 is an enlarged perspective view showing a portion (b) of FIG. 5. FIG.
4 is a cross-sectional view illustrating the conveyance guide plate of FIG. 3;
FIG. 5 is a diagram illustrating a curved conveyance path.
FIG. 6 is a cross-sectional view schematically showing the entire image forming apparatus according to the first embodiment of the present invention. FIG. 7 is a perspective view showing a connecting portion between the curved guide plate and the elastic member according to the second embodiment. is there.
FIG. 8 is a perspective view showing a connection portion between a conveyance guide plate and an elastic member according to a second embodiment.
FIG. 9 is a perspective view showing a connection portion between a conveyance guide plate and an elastic member according to a modification.
FIG. 10 is a perspective view showing a connection portion between a conveyance guide plate and an elastic member according to a modification.
FIG. 11 is a perspective view showing a connection portion between a conveyance guide plate and an elastic member according to a modification.
FIG. 12 is a perspective view showing a connection portion between a conveyance guide plate and an elastic member according to a modification.
FIG. 13 is a perspective view showing a connection portion between a conveyance guide plate and an elastic member according to a modification.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paper conveyance apparatus 20 Curved conveyance path 27 Conveyance guide board (paper guide board)
29 Curved guide plate (paper guide plate)
31, 33 Elastic member P Paper

Claims (4)

A curved conveyance path that guides the conveyed sheet, a first sheet guide plate that is provided substantially in parallel so as to sandwich the sheet in the conveyance path, and a first position that is provided at a change position in the conveyance direction of the sheet . and 2 paper guide plate, the transport direction rear end to the first sheet guide plate is fixed and the conveying direction leading end is positioned in the conveying path, a first elastic member that are in contact with the second paper guide plate, A paper transport device comprising: a second elastic member having a transport direction rear end fixed to the second paper guide plate and a transport direction front end positioned in the transport path ;
A sheet conveying apparatus characterized in that, at the leading ends in the conveying direction of the first and second sheet guide plates, the central portion in the conveying path width direction is recessed with respect to the conveying direction than both ends. A curved conveyance path that guides the conveyed sheet, a first sheet guide plate that is provided substantially in parallel so as to sandwich the sheet in the conveyance path, and a first position that is provided at a change position in the conveyance direction of the sheet . and 2 paper guide plate, the transport direction rear end to the first sheet guide plate is fixed and the conveying direction leading end is positioned in the conveying path, a first elastic member that are in contact with the second paper guide plate, A paper transport device comprising: a second elastic member having a transport direction rear end fixed to the second paper guide plate and a transport direction front end positioned in the transport path ;
A sheet conveying apparatus characterized in that, at the leading ends in the conveying direction of the first and second sheet guide plates, the central part in the conveying path width direction protrudes in the conveying direction from both ends. A conveying path curved to guide the sheet conveyed, a first paper guide plate arranged substantially parallel so as to sandwich the sheet into the conveying path, first provided in the transport direction of the change position of the paper and 2 paper guide plate, the transport direction rear end to the first sheet guide plate is fixed and the conveying direction leading end is positioned in the conveying path, a first elastic member that are in contact with the second paper guide plate, A paper transport device comprising: a second elastic member having a transport direction rear end fixed to the second paper guide plate and a transport direction front end positioned in the transport path ;
The sheet conveying apparatus according to claim 1, wherein the leading ends of the first and second sheet guide plates are formed obliquely with respect to a line perpendicular to the conveying direction in the width direction of the conveying path.   The front end of the first paper guide plate in the transport direction is provided near the entrance on the upstream side in the transport direction of the curved transport path where the paper is guided, and the front end of the second paper guide plate in the transport direction is the end of the curved transport path. The sheet conveying device according to claim 1, wherein the sheet conveying device is provided near the top of the curved portion.

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