JP2004262583A - Sheet delivery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent gross unevenness of a sheet by a pair of feeding rollers for feeding the sheet just after passing a fixing nip. <P>SOLUTION: This sheet delivery device is provided with a pair of the feeding rollers 7 for fastening and feeding the sheet S just after a heating heater 5 and a pressure roller 6, a swinging arm 18 for rotatably supporting a roller 12 which is a rotating body of one of the pair of the feeding rollers and supporting the roller to be swung along the approaching and separating direction with respect to a feeding roller 11 which is the other rolling body, a tensile spring 20 for energizing and press-contacting the roller to the feeding roller 11, and an openable and closable face up tray 2 for delivering the sheet S passing the pair of the feeding rollers 7 while the sheet surface is faced up. When the face up tray 2 is opened, the face up tray 2 is abutted with the swinging arm 18, the swinging arm 18 is swung against the energizing force of the tensile spring 20, and press-contact of the pair of the feeding rollers 7 is released. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet discharge device that conveys a sheet immediately after a fixing unit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic method, for example, forms an electrostatic latent image on a surface of a photosensitive drum as an image carrier, and transfers the electrostatic latent image on the photosensitive drum to a toner such as a developer. Then, the developed image is transferred to a sheet by a transfer device, and the toner image on the sheet is fixed by a fixing device using pressure, heat, or the like. And is discharged out of the apparatus.
[0003]
For example, in the conventional fixing device, a heater and a pressure roller as a fixing unit, and a pair of conveyance rollers including a conveyance roller and a roller are sequentially arranged from the upstream side in the sheet conveyance direction.
[0004]
The toner image transferred sheet that has reached the fixing device enters the fixing nip of the heater and the pressure roller. Then, while the sheet passes through the fixing nip, the transferred toner image is heated and pressed, and is fixed on the sheet surface.
[0005]
The sheet that has passed through the fixing device and has been subjected to the fixing process is placed in a face-up tray or a face-down tray in a state where the surface of the sheet faces upward (face-up) or faces downward (face-down). Emitted to either. When discharging the sheet face-up, the user opens the closed face-up tray with respect to the apparatus main body, and when discharging the sheet face-down, the user closes the open face-up tray.
[0006]
[Problems to be solved by the invention]
When the toner image fixed on the sheet surface is uniformly cooled, the gloss value (degree of gloss) of the image is also uniform. However, in the above-described conventional fixing device, immediately after the sheet passes through the fixing nip, Since there is a pair of transport rollers having a transport nip, the sheet that has passed through the fixing nip passes through the transport nip in a high temperature state. Therefore, when the user uses a sheet having a high gloss such as gloss paper or a gloss film, the portion of the sheet sandwiched between the pair of transport rollers having the transport nip immediately after the fixing nip is the other portion of the sheet. The gross value is different because of the rapid cooling compared to the above. For this reason, the band-shaped range pinched by the pair of conveying rollers on the image has a different gloss value from the portion of the sheet not pinched by the pair of conveying rollers, causing gloss unevenness that looks like roller marks. was there.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to prevent a sheet from being unevenly glossed by a pair of conveying rollers that convey a sheet immediately after passing through a fixing nip.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a typical configuration of the present invention includes a pair of transport rotators that sandwich and transport a sheet immediately after a fixing unit, and rotatably support one of the transport rotators. A swinging member that supports the one rotating body so as to swing toward and away from the other rotating body, and biases one rotating body of the transport rotating body toward the other rotating body. And an openable and closable loading tray for face-up discharge that discharges the sheet that has passed through the transport rotating body with the sheet surface facing upward, and when the loading tray is opened. The loading tray abuts on the swing member, the swing member swings against the urging force of the urging member, and the pressure contact of the transport rotating body is released.
[0009]
According to the above configuration, for example, when the user uses a sheet having a high gloss such as gloss paper or a gloss film, the stacking tray for face-up discharge is opened, and the pressure contact of the transport rotating body is released. Since the sheet that has passed through the fixing unit is stacked on the stacking tray for face-up discharge without being pinched by the conveyance rotating body immediately after the fixing unit, it is possible to prevent the occurrence of gloss unevenness in an image. .
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are to be appropriately changed depending on the configuration and various conditions of the apparatus to which the present invention is applied, and It is not intended to limit the scope of the invention to them only, unless specifically stated.
[0011]
[First Embodiment]
With reference to FIGS. 1 to 3, an image forming apparatus provided with a sheet discharge device according to an embodiment of the present invention will be described in detail. 1 to 3 show an image forming apparatus provided with a sheet discharging device according to an embodiment of the present invention.
[0012]
First, the overall configuration of the image forming apparatus according to the present embodiment will be briefly described with reference to FIG.
[0013]
When the image formation start signal is input, the laser scanner 30 irradiates a laser beam corresponding to the image information onto the photosensitive drum 31 rotating clockwise. As a result, an electrostatic latent image is formed on the photosensitive drum 31, and the electrostatic latent image is developed with toner by a developing device (not shown).
[0014]
When the image formation start signal is input, the sheets S stacked and stored in the cassette 32 are sequentially fed out from the uppermost sheet by the feed roller 33 rotating in the counterclockwise direction. The fed sheet S is sent to the registration roller pair 35 in the rotation stopped state by the conveyance roller pair 34.
[0015]
The sheet S sent to the registration roller pair 35 stops moving when a predetermined amount of loop is formed by the leading end of the sheet abutting the nip of the registration roller pair 35. By forming this loop, the skew state of the sheet S is corrected.
[0016]
The sheet S whose skew state has been corrected is transferred to a transfer section between the photosensitive drum 31 and the transfer roller 36 by a pair of registration rollers 35 that starts rotating at a predetermined timing with respect to the toner image on the photosensitive drum 31. Sent in. The toner image on the photosensitive drum 31 is transferred to the sheet S passing through the transfer section by the transfer roller 36.
[0017]
The sheet S on which the toner image has been transferred after passing through the transfer section is sent to the fixing device 1. Then, the toner image being transferred is fixed on the sheet surface by being heated and pressed in the process of passing through the fixing device 1.
[0018]
The fixed sheet S that has passed through the fixing device 1 is discharged to the discharge destination selected by the user. That is, when the sheet S is discharged with the surface of the sheet S facing upward, the sheet S can be discharged to the face-up tray 2, which is an openable and closable stacking tray for face-up discharge. On the other hand, when the sheet S is discharged with the front surface facing downward, the sheet S can be discharged to the face-down tray 3 at the top of the apparatus, which is a stacking unit for face-down discharge.
[0019]
The face-up tray 2 is provided to be openable and closable with respect to the apparatus main body. FIG. 1 shows a case where the face-up tray 2 is closed and the face-down tray 3 is selected as a discharge destination. It is discharged to 3.
[0020]
Here, as shown in FIG. 2, the fixing device 1 as a fixing unit includes a heater 5 and a pressure roller 6 as a fixing unit, and a pair of conveying rollers 7 as a pair of conveying rotating members. They are arranged in order from the side and are provided integrally.
[0021]
The heater 5 has a plate shape in which a heating element is formed on a ceramic substrate. The plate-shaped heater 5 is fixed to a flat portion (a portion facing the pressure roller 6) of a film guide 9 for guiding rotation (inner surface guide) of the cylindrical fixing film 8. I have. The film guide 9 is fixed at a predetermined position.
[0022]
The pressure roller 6 is rotatably provided at a position facing the heater 5. The driving force from a driving source such as a motor is transmitted to the pressure roller 6 to rotate in the counterclockwise direction in the drawing. As the pressure roller 6 rotates, the cylindrical fixing film 8 is driven to rotate while being guided by the film guide 9.
[0023]
The sheet S onto which the toner image has been transferred, which has reached the fixing device 1, is guided by the guide 10 and is guided to the fixing nip of the heater 5 and the pressure roller 6. While the sheet S passes through the fixing nip, the transferred toner image is heated and pressed, and is fixed on the sheet surface. The sheet S that has passed through the fixing nip enters the transport nip of the transport roller pair 7. The sheet S having undergone the fixing process by the pair of conveying rollers 7 is conveyed toward the pair of discharging rollers 4 while being guided by the conveying guide 37 shown in FIG. 1, and is discharged to the face-down tray 3 by the pair of discharging rollers 4. You.
[0024]
Next, a configuration of a characteristic portion of the present embodiment will be described with reference to FIGS. FIG. 2 shows a case where face-up ejection is selected by the user and the face-up tray 2 is opened. FIG. 3 schematically shows a state of the conveying roller pair 7 constituting the sheet discharging device in the longitudinal direction.
[0025]
In the figure, a transport roller pair 7 includes a transport roller 11 (the other rotating body) and a roller 12 (one rotating body) that can sandwich and transport the sheet S. The transport roller 11 is pressed into a transport roller shaft 13, and the transport roller shaft 13 is rotatably supported on a side plate 15 of the fixing device via a bearing 14. A gear 16 is attached to the transport roller shaft 13, and is driven to rotate by transmitting a driving force from a drive source of the apparatus main body. The roller 12 is rotatably mounted on a roller shaft 17, and the roller shaft 17 is mounted on one end of a substantially L-shaped swing arm 18. The swing arm 18 as a swing member is swingable about the rotation shaft 19 in the direction in which the transport roller pair 7 comes into contact with and separates from the transport roller pair 7. When the face-up tray 2 is closed, a tension spring as an urging member is used. Due to the tension of 20, the roller 12 as one rotating body comes into contact with the transport roller 11 as the other rotating body. The face-up tray 2 is opened and closed around a rotation shaft 21, and when the face-up tray 2 is opened, an operation shaft 22 provided near the rotation shaft 21 of the face-up tray 2 is moved to the other end of the swing arm 18. The swing arm 18 rotates counterclockwise against the urging force of the tension spring 20 and, as shown in FIG. The rollers 12, which are the rotating bodies of, are separated.
[0026]
Therefore, when the face-up discharge is selected and the face-up tray 2 is opened, the conveyance roller 11 and the roller 12 are separated from each other in conjunction with the opening operation of the face-up tray 2, and the sheet S passing through the fixing nip is conveyed. The paper passes through the space between the roller 11 and the roller 12 and is sent to the face-up tray 2.
[0027]
As described above, according to the present embodiment, when the user uses a sheet having a high gloss such as gloss paper or a gloss film, the face is a release mechanism that releases the contact pressure of the transport nip of the transport roller pair 7. By opening the up tray 2, the contact pressure of the transport nip is released, and the sheet that has passed through the fixing nip is kept at a high temperature without being pinched by the transport roller pair 7 having the transport nip immediately after the fixing nip. Since the image is directly stacked on the face-up tray 2, it is possible to prevent the occurrence of gloss unevenness in the image.
[0028]
[Other embodiments]
In the above-described embodiment, when the face-up tray 2 is opened and the swing arm 18 rotates against the urging force of the extension spring 20, the other rotating body is the one rotating body from the transport roller 11. Although the configuration in which the rollers 12 are separated from each other has been illustrated, the present invention is not limited to this, and the configuration may be such that the pressure contact of the transport roller pair 7 is released to the extent that gloss unevenness does not occur in the image.
[0029]
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, other image forming apparatuses such as a copying machine and a facsimile apparatus, or a combination of these functions may be used. Using another image forming apparatus such as a multifunction machine or a transfer material carrier for carrying a transfer material such as a sheet, the toner images of the respective colors are sequentially superimposed and transferred onto the transfer material carried on the transfer material carrier. An image forming apparatus or an image forming apparatus that uses an intermediate transfer body, sequentially transfers toner images of respective colors onto the intermediate transfer body in a superimposed manner, and collectively transfers the toner images carried on the intermediate transfer body onto a transfer material. The same effect can be obtained by applying the present invention to a fixing device used in the image forming apparatus.
[0030]
In the above-described embodiment, an image forming apparatus capable of forming a monochrome image has been described as an example of the image forming apparatus. However, the present invention is not limited to this. For example, an image forming apparatus capable of forming a color image may be used. Similarly, in the image forming apparatus, when a sheet having a high gloss such as gloss paper or a gloss film is used, it is possible to prevent the image from having uneven gloss.
[0031]
Although various embodiments of the present invention have been shown and described, the spirit and scope of the present invention are not limited to the specific description and drawings in this specification. Hereinafter, examples of embodiments of the present invention will be listed.
[0032]
[Embodiment 1]
A pair of transport rotators for nipping and transporting the sheet immediately after the fixing unit, and rotatably supporting one of the transport rotators, and the one rotary member relative to the other rotary member. A swing member that swingably supports in the direction of contact and separation, a biasing member that biases one rotating body of the transport rotating body against the other rotating body and presses the rotating body, and a sheet that has passed through the transport rotating body. A stackable tray for face-up discharge that discharges the sheet surface upward, and when the stacking tray is opened, the stacking tray comes into contact with the swinging member and A sheet discharging device, wherein a moving member swings against the urging force of the urging member, and the pressure contact of the transport rotating body is released.
[0033]
[Embodiment 2]
In addition to the stacking tray for face-up discharge, the stacking unit for face-down discharge that discharges the sheet with the surface of the sheet facing downward, and in a state where the stacking tray is closed, the sheet is a member of the urging member. 2. The sheet discharging apparatus according to claim 1, wherein the sheet is nipped and conveyed by the conveying rotating body in a pressing state by an urging force, and is discharged to the face-down discharging stacking unit.
[0034]
[Embodiment 3]
3. The sheet discharging apparatus according to claim 1, wherein the transport rotator is provided integrally with a fixing unit having a fixing unit that fixes a toner image on a sheet.
[0035]
[Embodiment 4]
In an image forming apparatus having a fixing unit for fixing a toner image on a sheet, the sheet discharging device according to any one of the first to third embodiments is provided as a conveying unit for nipping and conveying the sheet immediately after the fixing unit. An image forming apparatus comprising:
[0036]
【The invention's effect】
As described above, according to the present invention, for example, when a user uses a sheet having a high gloss such as gloss paper or a gloss film, the stacking tray for face-up discharge is opened, and the press-contact of the transport rotating body is performed. Is released, the sheet that has passed through the fixing unit is stacked on the stacking tray for face-up discharge without being pinched by the transport rotating body immediately after the fixing unit. Can be prevented.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an image forming apparatus. FIG. 2 is a detailed view around a fixing device in the image forming apparatus. FIG. 3 is a detailed view around a conveying roller pair in the fixing apparatus.
S ... sheet 1 ... fixing device (fixing unit)
2… Face up tray (loading tray for face up)
3. Face down tray (loading section for face down)
4 ... discharge roller pair 5 ... heater 6 ... pressure roller 7 ... transport roller pair (transport rotating body)
8 fixing film 9 film guide 10 guide 11 conveying roller (the other rotating body)
12 ... Roller (one rotating body)
13: conveying roller shaft 14: bearing 15: side plate 16: gear 17: roller shaft 18: swing arm (swing member)
19 ... rotating shaft 20 ... tension spring (biasing member)
21 ... rotating shaft 22 ... working shaft 30 ... laser scanner 31 ... photosensitive drum 32 ... cassette 33 ... feeding roller 34 ... transport roller pair 35 ... registration roller pair 36 ... transfer roller 37 ... transport guide

Claims (1)

A pair of transport rotators that sandwich and transport the sheet immediately after the fixing unit;
A swinging member that rotatably supports one of the rotating bodies of the transport rotating body, and that swingably supports the one rotating body in the direction of contact and separation with respect to the other rotating body;
An urging member that urges one of the rotating members of the transport rotating member against the other rotating member and presses against the rotating member,
An openable and closable loading tray for face-up discharge, which discharges the sheet having passed through the transport rotating body with the sheet surface facing upward,
Has,
When the stacking tray is opened, the stacking tray comes into contact with the swing member, the swing member swings against the urging force of the urging member, and the pressure contact of the transport rotating body is released. A sheet discharging device characterized by the above-mentioned.

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