JPH11130311A - Sheet material carrier device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of strange sound of a sheet material and exfoliation of images caused by sliding rubbing of the sheet material and a carrier guide by arranging an auxiliary guide member for reducing sliding rubbing with the sheet material at a part of at least a guide means. SOLUTION: A carrier guide 19 as a guide means forming a curved carrier path 18 is used also as the carrier guide of a face-up tray 10 in a state that the face-up tray 10 is opened. At a part of the carrier guide 19 of this curved carrier path 18, an auxiliary guide 21 formed by materials of POM and PFA reducing sliding rubbing with a sheet material S is locked. Three auxiliary guides 21 for reducing sliding rubbing of the sheet material S and the carrier guide 19 are mounted at prescribed intervals in the direction which is orthogonally crossed with the carrier direction of the carrier guide 19. Thus, sliding rubbing of the carrier guide 19 forming the curved carrier path 18 and the sheet material S is reduced, and strange sound and exfoliation of images due to chattering of the sheet material S caused by sliding rubbing can be prevented.

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 having guide means for forming a conveying path for guiding a sheet, and more particularly to an electrophotographic image forming apparatus such as a printer or a copying machine. The present invention relates to a sheet conveying device to be used.

[0002]

2. Description of the Related Art A schematic configuration of a conventional image forming apparatus is described as follows.
A description will be given along the flow of the sheet material with reference to FIG. The sheet material S stacked and stored in the cassette 101 is sequentially fed out from the uppermost sheet material by a sheet feeding roller 102 rotating counterclockwise in FIG.
Is sent to the image forming unit 105.

On the other hand, in an image forming unit 105, a laser beam corresponding to the image information is irradiated by a laser scanner 106 onto a photosensitive drum 107 rotating clockwise in the figure to form an electrostatic latent image. The electrostatic latent image is transferred to the photosensitive drum 10
Developing means (not shown) as process means acting on 7
The image is visualized (toner image).

The toner image on the photosensitive drum 107 is transferred by the transfer roller 108 to the sheet material S sent to the image forming unit 107 by the pair of conveying rollers 103 and 104 at the same timing as the image forming operation. . Thereafter, the sheet material S is heated and pressed while passing through the fixing device 109, so that the toner image is fixed.

The sheet material S which has passed through the fixing device 109 and has been subjected to the fixing process is discharged to either the face-up tray 110 or the face-down tray 111. The discharge destination is determined by the operator selecting whether to discharge the sheet material S face-up or face-down.

In other words, when the paper is to be discharged face-up, the operator rotates the face-up tray 110 rotatable about the support shaft 112 from the solid line position in the drawing to the broken line position in the drawing. Then, this face-up tray 110
The flapper at the position indicated by the solid line in the figure
113 rotates around the support shaft 114 in the counterclockwise direction in the figure,
Move to the broken line position in the figure. As a result, the sheet material S that has been subjected to the fixing process as described above is guided by the flapper 113 at the position indicated by the broken line in the figure and is discharged onto the face-up tray 110.

When the face-up sheet is discharged face-down, when the operator closes the face-up tray 110, which is open at the position indicated by the broken line in FIG. The flapper 113 rotates clockwise in the drawing around the support shaft 114, and moves to the solid line position in the drawing. As a result, the sheet material S on which the fixing process has been performed as described above is guided by the flapper 113 and the conveyance guide 116 forming the curved conveyance path 115 at the solid line position in the figure, and is guided by the discharge roller pair 117 onto the face-down tray 111. Is discharged to

The flapper 113 is configured to interlock with the opening / closing operation of the face-up tray 110 via an interlocking lever 118 fixed to one end of a support shaft 114.

[0009]

However, in recent years,
In order to reduce the size of the apparatus, the curvature of the curved conveyance path 115 between the fixing device 109 and the pair of paper discharge rollers 117 tends to be small. For this reason, the sheet material S that has passed through the fixing device 109 swells outward greatly when nipping the sheet discharge roller pair 117, and strongly rubs against the transport guide 116 that forms the transport path 115, and the sheet material is rubbed by the rubbing. There was a possibility that chattering and abnormal sound would occur.

For example, when the conventional apparatus as described above is provided with a re-feeding path so that images can be formed on both sides (front and back) of the sheet material, the sheet material on which images are formed on both sides is Since the toner formed in the image formed on the surface on the side of the conveyance guide 116 is in a semi-molten state immediately after passing through the fixing device, the sheet material chatters due to the rubbing with the conveyance guide 116 as described above, and the noise is generated. There was a risk of doing. In particular, when the sheet material is thick or when an image having a high printing ratio such as a photographic image is provided on the side of the conveyance guide 116, the sliding friction with the conveyance guide 116 is strong, so that the above-described noise generation opportunity may occur. Increase.

Further, even in an apparatus capable of forming an image on one side of a sheet material, in the case of an apparatus configured to form an image on the side of the conveyance guide 116, the same problem occurs even when printing on one side.

[0012] For a place where the friction between the sheet material and the sheet material causing the sound generation is strong, a method of making the entire conveyance guide a member for reducing the friction can be considered. There was a problem in such points.

When a low-melting-point toner is used for the purpose of speeding up the apparatus, the temperature of the fixed toner image on the sheet material immediately after passing through the fixing device has not been lowered.
If the transfer toner is strongly rubbed with the transport guide 116, the fixed toner image may be peeled off from the sheet material.

SUMMARY OF THE INVENTION An object of the present invention is to prevent the sheet material from being distorted and the image from being peeled off due to friction between the sheet material and the conveyance guide.

[0015]

According to the present invention, there is provided a sheet conveying apparatus having guide means for forming a conveying path for guiding a sheet material. An auxiliary guide member for reducing rubbing with a sheet material is arranged at least in a part of the guide means.

In order to achieve the above object, a representative image forming apparatus according to the present invention comprises an image forming apparatus having an image forming means for forming an image on a sheet material, wherein an image is formed by the image forming means. An auxiliary guide member for reducing rubbing of the sheet material with an image is arranged at least in a part of a guide unit that forms a conveyance path for guiding the sheet material.

The auxiliary guide member is made of a material such as POM and PFA that reduces sliding friction.

The auxiliary guide member is a rotatable rotating body.

[0019] The auxiliary guide member is characterized in that it projects to the sheet material side from the sheet material guide surface of the guide means.

[0020] The auxiliary guide member is arranged at least in a part of guide means forming a curved conveyance path.

According to the above configuration, for example, POM, PF
The sliding friction between the guide means and the sheet material is reduced by an auxiliary guide member made of a material such as A or the like, or a rotatable rotating body as the auxiliary guide member. Therefore, it is possible to prevent the noise and the peeling of the image due to the chatter of the sheet material caused by the above.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a sheet conveying apparatus and an image forming apparatus to which the present invention is applied will be specifically described below with reference to the drawings. In the following embodiments, an image forming apparatus having a sheet conveying device to which the present invention is applied will be described as an example.

[First Embodiment] An image forming apparatus according to a first embodiment will be described in detail with reference to the drawings. FIG. 1 shows an overall schematic configuration of an image forming apparatus to which the present invention is applied.

First, in the image forming apparatus shown in FIG. 1, when a print start signal is inputted, a laser scanner 1 rotates a laser beam corresponding to image information in an image forming section 2 in a clockwise direction in the figure. Irradiates on the photoreceptor drum 3 which is present. As a result, an electrostatic latent image is formed on the photosensitive drum 3 whose surface is uniformly charged by a charging unit (not shown), and this electrostatic latent image is visualized by a developing unit (not shown). (Toner image).

On the other hand, when a print start signal is issued, the sheet materials S stacked and stored in the cassette 4 are sequentially fed out from the uppermost sheet material S by the sheet feeding roller 5 rotating counterclockwise in the drawing. Then, the sheet is sent to the pair of registration rollers 7 in a rotation stopped state by the pair of conveying rollers 6. The sheet material S sent to the registration roller pair 7 stops when its leading end abuts the nip of the registration roller pair 7 to form a predetermined amount of loop. By this loop formation, the skew state of the sheet material is corrected.

The sheet material S whose skew has been corrected is rotated by the registration roller pair 7 which starts rotating at a predetermined timing with the image forming operation as described above.
And is transferred to a transfer section between the transfer roller 8 and And
When the sheet material S passes through the transfer section, the toner image formed on the photosensitive drum 3 is transferred by the transfer roller 8.

The sheet material S that has passed through the transfer section is transferred to the fixing device 9.
The toner image is heated and pressurized while passing through the fixing device 9 to fix the transferred toner image. The sheet material S that has passed through the fixing device 9 is discharged to a discharge destination (the face-up tray 10 or the face-down tray 11) selected by the operator.

In FIG. 1, reference numeral 12 denotes a flapper for switching the conveying direction of the sheet material S which has been subjected to the fixing process, which is interlocked with the opening / closing operation of the face-up tray 10 via an interlocking lever 14 fixed to one end of a support shaft 13. It is configured to be. Therefore, the selection of the discharge destination by the operator is performed by the opening / closing operation of the face-up tray 10.

That is, a face-up tray is used as a discharge destination.
When selecting 10, the operator rotates the face-up tray 10 rotatable about the support shaft 15 from the solid line position in the drawing to the broken line position in the drawing. Then, in conjunction with the turning operation of the face-up tray 10, the flapper 12 located at the solid line position in the figure rotates counterclockwise around the support shaft 13 and moves to the broken line position in the figure. . As a result, the flapper 12 opens the passage 16 to the face-up tray 10 and closes the passage 17 to the face-down tray 11.
Therefore, the sheet material S that has been subjected to the fixing process as described above is
The face-up tray 10 at the position indicated by the broken line in FIG.
The paper is ejected on top.

Also, a face-down tray is used as a discharge destination.
In the case of selecting 11, the operator closes the face-up tray 10 opened at the broken line position in the figure to the solid line position in the figure,
The reference numeral 12 rotates around the support shaft 13 in the clockwise direction in the figure and moves to the position indicated by the solid line in the figure. As a result, the flapper 12 closes the passage 16 to the face-up tray 10 and opens the passage 17 to the face-down tray 11. Accordingly, the sheet material S that has been subjected to the fixing process as described above is transported by a transport guide 19 as a guide unit that forms a curved transport path 18 through the path 17.
And the paper is discharged onto the face-down tray 11 by the paper discharge roller pair 20.

The sheet conveying speed Vf of the fixing device 9 and the sheet conveying speed Vo of the discharge roller pair 20 are set so that the relationship between them becomes Vo> Vf. ing.

In this embodiment, the conveyance guide 19 as a guide means for forming the curved conveyance path 18 also functions as a conveyance guide for the face-up tray 10 when the face-up tray 10 is opened.

As shown in FIGS. 2 and 3, an auxiliary guide 21 made of POM or PFA material for reducing rubbing with a sheet material is provided on a part of the transport guide 19 of the curved transport path 18. Is locked. FIG. 2 is an explanatory view of the configuration of the transport guide portion, and FIG. 3 is a view taken in the direction of arrow B in FIG.

As shown in FIGS. 2A and 2C, the sheet conveying surface 21a of the auxiliary guide 21 is slightly larger than the sheet conveying surface 19a of the conveying guide 19 (the length t in the present embodiment).
Only) It protrudes to the transport path side.

As shown in FIG. 2B, the auxiliary guide 21 is attached to the transport guide 19 by first attaching a substantially L-shaped portion 21b at one end of the auxiliary guide 21 to a predetermined position of the transport guide 19. It is inserted into the square hole 19b provided at the position. At this time, the substantially L-shaped portion 21b at one end of the auxiliary guide 21 is brought into contact with the surface 19c of the transport guide 19.
Insert so that it goes around. After that, the auxiliary guide 21
The positioning boss 21c provided substantially at the center of the
Is rotated in the direction of the arrow in the figure so as to engage with the hole 19d provided at a predetermined position of the auxiliary guide 21.
21d is locked by the rib 19e of the transport guide 19 shown in FIG. FIG. 2C is a sectional view taken along line AA of FIG.

In this embodiment, as shown in FIG.
Three auxiliary guides 21 for reducing friction between the sheet material S and the transport guide 19 are attached at predetermined intervals in a direction orthogonal to the transport direction of the transport guide 19.

As described above, according to the present embodiment, for example, the auxiliary guide 21 formed of a material such as POM, PFA, etc., which reduces the friction between the sheet and the transport guide 19 which forms the curved transport path 18 and the sheet. As the friction with the material is reduced,
It is possible to prevent noise and image peeling due to chatter of the sheet material caused by the rubbing.

[Second Embodiment] An image forming apparatus according to a second embodiment will be described with reference to FIGS. FIG.
FIG. 5 is an explanatory diagram of a transport guide unit that forms a curved transport path in the image forming apparatus according to the second embodiment, and FIG. 5 is a cross-sectional view taken along line CC in FIG.

Since the schematic configuration of the image forming apparatus is substantially the same as that of the above-described embodiment, a detailed description is omitted here.

In this embodiment, a rotatable rotating body is provided as an auxiliary guide member for reducing the friction between the sheet material and the conveyance guide. 4 and 5, reference numeral 22 denotes a rotating roller as a rotating body, and a rotating shaft 22a of the rotating roller 22 has a transport guide 23 as a guide means.
The U-groove 23a is supported by the U-groove 23a provided
23a is always urged from the opening side to the closing side. The sheet material transport surface 22b of the rotating roller 22 slightly protrudes (by the length t in the present embodiment) from the sheet material transport surface 23b of the transport guide 23 toward the transport path.

In this embodiment, as shown in FIG.
Two rotating rollers 22 for reducing friction between the sheet material S and the transport guide 19 are attached at a predetermined interval in a direction orthogonal to the transport direction of the transport guide 19.

As described above, according to the present embodiment,
As in the above-described embodiment, the rubbing between the sheet guide and the conveyance guide 23 forming the curved conveyance path is reduced by the rotatable rotating rollers 22, so that the sheet material caused by the rubbing is reduced. It is possible to prevent sound distortion and peeling of an image due to chatter.

For example, even when a thick sheet material passes while rubbing with the transport guide 23, the rotatable rotary roller 22 is rubbed with the sheet material in the direction of the arrow (counterclockwise) in FIG. As the sheet rotates, the friction between the sheet material and the conveyance guide is reduced, so that the noise caused by the friction and the peeling of the image can be prevented.

Third Embodiment An image forming apparatus according to a third embodiment will be described with reference to FIG. FIG. 6 is a schematic sectional view illustrating a schematic configuration of the image forming apparatus according to the third embodiment.

The image forming apparatus according to the present embodiment has a configuration in which a re-feeding device is detachably provided for forming images on both sides of a sheet material. Since the configuration is substantially the same as that of the embodiment, members having the same functions are denoted by the same reference numerals, and detailed description is omitted.

As shown in FIG. 6, a re-feeding device 32 is detachably attached to the image forming apparatus main body 31. The single-sided / double-sided automatic switching means 34 in the re-feeding device 32 includes a support shaft 35a.
And a plunger (solenoid) 36 that can swing about the
A cam follower 35b is formed to abut the interlocking lever 14 fixed to the twelve support shafts 13, and a plunger 36 is connected to the other end.

The re-feeding device 32 is a main body of the image forming apparatus.
A conveyance guide 37 serving as a guide unit for introducing the sheet material S discharged from the sheet feeding device 31 into the re-feeding device 32;
Guide 38 as an auxiliary guide member for reducing the sliding of the image on the sheet material S, a pair of switchback rollers 39 capable of normal and reverse rotation for performing switchback, and paper for detecting the presence or absence of the sheet material S. The presence / absence detection means 40, transport paths 41 and 42 for transporting the switched back sheet material S into the image forming apparatus main body 31, and pairs of transport rollers 43 and 44 are provided.

A double-sided image forming operation of the image forming apparatus according to the present embodiment based on the above configuration will be described. In the automatic double-sided printing mode, the face-up tray 33 is closed as shown in the figure. Further, the plunger 36 is pulled in the direction of the arrow, and the switching lever 35 rotates clockwise in the figure around the support shaft 35a, and a cam follower 35 at one end of the switching lever 35 is provided.
b presses the interlocking lever 14, and the flapper 12 rotates counterclockwise in FIG.
Is formed.

Accordingly, the sheet material S which has passed through the fixing device 9 and has been subjected to the fixing process is transferred to the conveying path formed as described above.
It is introduced through 45 into the refeeding device 32. The curved transport path 46 leading to the switchback roller pair 39
Then, since the sheet material S is guided by the auxiliary guide 38 disposed on the conveyance guide 37, the rubbing between the image of the sheet material S and the conveyance guide 37 is reduced, and the noise of the sheet material generated by the rubbing is reduced. And peeling of images can be prevented.

The sheet material S that has passed through the transport guide 37 as described above passes through the paper presence / absence detecting means 40 and is transported to the transport path 47 by the switchback roller pair 39. At this time, when the paper presence / absence detection means 40 detects that the rear end of the sheet material S has passed the paper presence / absence detection means 40, the switchback roller pair 39 is driven to rotate in the reverse direction, and the sheet material S is conveyed to the transport paths 41 and 42.
The main body of the image forming apparatus by the pair of conveying rollers 43 and 44 via
It is introduced into a transport path 48 in 31.

Thereafter, the sheet S is sent to the image forming section 2 again from the rear end with a surface opposite to the surface on which the image is formed first,
After the image is formed, the sheet passes through the fixing device 9 and is ejected onto the face-down tray 11 by the sheet ejection roller pair 20.

As described above, according to the present embodiment,
In the same manner as in the above-described embodiment, in the curved conveyance path in the re-feeding device, the curved conveyance path is formed by an auxiliary guide 38 formed of a material such as POM, PFA or the like that reduces rubbing.
Since the rubbing between the sheet guide S and the conveyance guide 37 forming the sheet 46 is reduced, it is possible to prevent the noise and the peeling of the image due to the chattering of the sheet material caused by the rubbing.

[Other Embodiments] In the above embodiment,
As an auxiliary guide member for reducing the rubbing between the transport guide and the sheet material, the configuration in which the auxiliary guide 21 is arranged at three places of the transport guide or the rotating rollers 22 are arranged at two places of the transport guide has been exemplified. However, the present invention is not limited to this, and the arrangement position, number, shape, and the like of the auxiliary guide members may be appropriately set as needed.

As the guide means, a conveyance guide forming a curved conveyance path on the downstream side of the fixing device or a conveyance guide forming a curved conveyance path in the re-feeding device is exemplified, but the present invention is not limited to this. If the sheet material rubs and causes noise or peeling of the image,
For example, the same effect can be obtained by arranging the auxiliary guide member as described above in a conveyance guide forming another conveyance path or a conveyance guide forming a substantially straight conveyance path.

In the above-described embodiment, a printer is exemplified as an image forming apparatus. However, the present invention is not limited to this. For example, another image forming apparatus such as a copying machine or a facsimile apparatus may be used. The same effect can be obtained by applying the present invention to the image forming apparatus.

Further, in the above-described embodiment, the electrophotographic method is exemplified as the recording method, but the recording method is not limited to this, and another recording method such as an ink jet method may be used.

[0057]

As described above, according to the present invention,
At least a part of the guide means for guiding the sheet material is provided with an auxiliary guide member for reducing rubbing with the sheet material, so that rubbing between the guide means and the sheet material is reduced. Distortion due to chatter of the sheet material and peeling of the image are prevented.

For example, in an image forming apparatus such as a printer, by arranging the auxiliary guide member on at least a part of the guide means for rubbing the image on the sheet material, the rubbing between the image on the sheet material and the guide means is achieved. Is reduced,
It is possible to prevent noise generated due to rubbing between the image on the sheet material and the guide means, and also prevent peeling of the image from the sheet material due to the rubbing. In particular, the present invention is effective for an image forming apparatus that can be reduced in size and speed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an overall configuration of an image forming apparatus according to a first embodiment.

FIG. 2 is a cross-sectional view of a conveyance guide unit that forms a curved conveyance path in the image forming apparatus.

FIG. 3 is a view taken in the direction of arrow B in FIG.

FIG. 4 is an explanatory diagram of a conveyance guide unit that forms a curved conveyance path in the image forming apparatus according to the second embodiment.

5 is a sectional view taken along the line CC of FIG.

FIG. 6 is a schematic cross-sectional view illustrating an overall configuration of an image forming apparatus according to a third embodiment.

FIG. 7 is an explanatory diagram of a conventional image forming apparatus.

[Explanation of symbols]

 S: Sheet material 1 ... Laser scanner 2 ... Image forming unit 3 ... Photoconductor drum 4 ... Cassette 5 ... Paper feed roller 6 ... Transport roller pair 7 ... Registration roller pair 8 ... Transfer roller 9 ... Fixing device 10 ... Face-up tray 11 … Face down tray 12… Flapper 13… Spindle 14… Interlocking lever 15… Spindle 16… Path 17… Path 18… Transport path 19… Transport guide 19a… Sheet transfer surface 19b… Square hole 19c… Side 19d… Hole 19e … Rib 20… Discharge roller pair 21… Auxiliary guide 21a… Sheet conveying surface 21b… Large end portion 21c… Boss 21d… Locking portion 22… Rotating roller 22a… Rotating shaft 22b… Sheet conveying surface 23… Conveying guide 23a ... U groove 23b ... sheet material conveying surface 24 ... urging means 31 ... image forming apparatus main body 32 ... refeeding device 33 ... face-up tray 34 ... switching means 35 ... switching lever 35a ... support shaft 36 ... plastic Ja 37 ... conveying guide 38 ... auxiliary guide 39 ... switchback roller pair 40 ... sheet presence detection means 41, 42 ... conveying path 43, 44 ... conveying roller pair 45 ... conveying path 46 ... conveying path 47 ... conveying path 48 ... conveying path

Claims (10)

[Claims] 1. A sheet material transporting apparatus having a guide means for forming a transport path for guiding a sheet material, wherein an auxiliary guide member for reducing rubbing with the sheet material is arranged at least in a part of the guide means. A sheet material conveying device characterized in that: 2. The method according to claim 1, wherein the auxiliary guide member is a POM or PFA.
The sheet conveying device according to claim 1, wherein the sheet conveying device is formed of a material that reduces rubbing, such as. 3. The sheet conveying apparatus according to claim 1, wherein the auxiliary guide member is a rotatable rotating body. 4. The sheet material transport according to claim 1, wherein the auxiliary guide member protrudes toward the sheet material side of the sheet material guide surface of the guide means. apparatus. 5. The sheet according to claim 1, wherein the auxiliary guide member is disposed on at least a part of a guide unit that forms a curved conveyance path. Material transfer device. 6. An image forming apparatus having image forming means for forming an image on a sheet material, wherein at least a part of a guide means for forming a conveying path for guiding the sheet material on which an image is formed by the image forming means, An image forming apparatus, comprising an auxiliary guide member for reducing rubbing with the sheet material. 7. The auxiliary guide member includes POM, PFA.
The image forming apparatus according to claim 6, wherein the image forming apparatus is formed of a material that reduces rubbing, such as. 8. The image forming apparatus according to claim 6, wherein the auxiliary guide member is a rotatable rotating body. 9. The image forming apparatus according to claim 6, wherein the auxiliary guide member protrudes toward a sheet material side of the sheet material guide surface of the guide unit. . 10. The apparatus according to claim 6, wherein the auxiliary guide member is disposed on at least a part of guide means forming a curved conveyance path.
Item 10. The image forming apparatus according to item 1.