JP2004053987A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which removal of an exterior cover is not necessary when attaching/detaching a fixing unit without bringing the cost up. <P>SOLUTION: In an image forming apparatus fixing a sheet carrying an unfixed image at a fixing unit 1 and ejecting to an ejecting part 4, the fixing unit 1 is constituted as a removable unit to the apparatus main body and a fixing cover 40 covering the attaching/detaching direction of the fixing unit 1 is constituted integrally to the fixing unit 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a printer for a computer, a copying machine, and a facsimile, and more particularly, to an image forming apparatus having a fixing unit for fixing an image.
[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. To develop a visible image. The developed image is transferred to a transfer material by a transfer device to carry the image on the transfer material, and the toner image on the transfer material is fixed by a fixing device using pressure, heat, or the like, and the fixed transfer material is It is discharged outside the device through the discharge path.
[0003]
In the fixing device, a heater and a pressure roller as fixing means are arranged. The toner image transferred sheet that has reached the fixing device enters the fixing nip of the heater and the pressure roller. While the sheet passes through the fixing nip, the transferred toner image is heated and pressed to be fixed on the sheet surface.
[0004]
Further, since the life of components such as the pressure roller of the fixing device is shorter than the life of the device main body, the fixing device is often configured as a fixing unit detachable from the device main body. Further, in order to facilitate a user's jam clearance in the vicinity of the fixing nip, the fixing device is often configured as a fixing unit detachable from the apparatus main body.
[0005]
Then, in order for the user to remove the fixing unit from the apparatus main body, first, the outer cover in the attaching / detaching direction of the fixing unit is removed, and then the fixing unit is removed.
[0006]
[Problems to be solved by the invention]
Therefore, in this type of conventional image forming apparatus, when the user attaches and detaches the fixing unit, the user must first remove the outer cover, which increases the user's actions when exchanging the fixing unit and when clearing a jam. There was a problem that the sex was not good. In addition, there is also a problem that after attaching the fixing unit, the user forgets to attach the outer cover, and the apparatus main body does not operate.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to eliminate the need for a user to remove an exterior cover when attaching and detaching a fixing unit without increasing the cost. It is intended to provide a high image forming apparatus.
[0008]
[Means for Solving the Problems]
A typical configuration according to the present invention for achieving the above object is an image forming apparatus in which a sheet carrying an unfixed image is fixed by a fixing unit and discharged to a discharge unit. The fixing unit is configured as a detachable unit, and an exterior cover that covers the attaching / detaching direction of the fixing unit is integrally formed with the fixing unit.
[0009]
In the above configuration, the exterior cover that covers the mounting / detaching direction of the fixing unit is integrated with the fixing unit, eliminating the need to remove the exterior cover before removing the fixing unit. , The detachability of the fixing unit is improved.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
<< Overall Configuration of Image Forming Apparatus >>
First, the overall configuration of the image forming apparatus will be briefly described with reference to FIG.
[0011]
When the recording 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).
[0012]
When the recording start signal is input, the sheets S stacked and stored in the cassette 32 are sequentially fed out from the uppermost sheet by the feeding 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.
[0013]
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.
[0014]
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.
[0015]
The sheet S to which the toner image has been transferred after passing through the transfer unit is sent to the on-demand type fixing unit 1. Then, the toner image being transferred is fixed on the sheet surface by being heated and pressed in the course of passing through the fixing unit 1. The sheet S that has undergone the fixing process that has passed through the fixing device 1 is discharged to the face-down tray 4 by the discharge roller 3 via the intermediate conveyance roller 2.
[0016]
｛Fusing unit｝
Here, the on-demand type fixing unit 1 as a fixing unit will be described with reference to FIG. A heater 5 and a pressure roller 6 as a fixing unit, and a conveying roller pair 7 are arranged in this order from the upstream side in the sheet conveying direction.
[0017]
The heater 5 has a plate shape. 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.
[0018]
The pressure roller 6 is attached at a position facing the heater 5. Drive from a main motor (not shown) is transmitted to the pressure roller 6, and the pressure roller 6 rotates counterclockwise. The cylindrical fixing film 8 is rotated by the rotation of the pressure roller 6 while being guided by the film guide 9.
[0019]
The toner image transferred sheet S that has reached the fixing unit 1 is guided by the guide 10 and enters 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 (transport unit) 7. The sheet S that has been subjected to the fixing process and discharged by the pair of conveying rollers 7 is sent to the face down tray 2 while being guided by the conveying guide (rib) 40a.
[0020]
Next, a configuration of a characteristic portion of the present embodiment will be described with reference to FIGS.
[0021]
3 and 4 are perspective explanatory views of the fixing unit 1. FIG. FIG. 5 is an explanatory view showing a state where the fixing unit 1 is removed from the apparatus main body, and FIG. 6 is an explanatory view showing a state where the cover is opened.
[0022]
In the figure, reference numeral 40 denotes a fixing cover which is an exterior cover integrally formed with the conveyance guide 40a, reference numeral 41 denotes a fixing lower cover which is an exterior cover that covers a lower side of the fixing unit 1, and reference numeral 42 denotes a top and bottom of the fixing cover 40. A lock lever that locks to the main body of the fixing unit 1 near the upper side of the intermediate position. As shown in FIG. 3, the fixing cover 40 and the lower fixing cover 41 are formed integrally with the fixing unit 1, and as shown in FIG. The fixing unit 1 is inserted into the apparatus main body, and is fixed to the apparatus main body by rotating the lock lever 42.
[0023]
As shown in FIG. 6, the fixing cover 40 is configured to be openable and closable around a lower side of the cover as a fulcrum (not shown). When the fixing cover 40 integrated with the conveyance guide 40a is opened, the conveyance path is opened. Thus, the user can access the intermediate conveyance roller 2 and the vicinity of the conveyance roller pair 7 and the jammed paper can be easily processed from the vicinity of the fixing nip to the vicinity of the intermediate conveyance roller 2. As shown in FIG. 4, when the fixing cover 40 is closed, the lock claw 40b is locked to the protrusion 43a of the fixing upper cover 43 of the fixing unit main body.
[0024]
FIGS. 7A and 7B are simplified explanatory diagrams showing the relationship between the lock claw 40b and the protrusion 43a. FIG. 7A shows a case where the fixing unit 1 is not mounted on the apparatus main body, and FIG. Shows the case where it is attached to. (C) shows a state in which the fixing unit 1 is mounted on the apparatus main body, and an upper end surface of the fixing cover 40 abuts against a contact portion 50 which is a step provided on the adjacent exterior cover 51. It is.
[0025]
When the fixing unit 1 is not mounted on the apparatus main body, as shown in FIG. 7A, there is a gap between the lock claw 40b and the protrusion 43a, and there is play in the rotation direction of the fixing cover 40.
[0026]
When the fixing unit 1 is mounted on the apparatus main body, the fixing cover 40 holds the outer cover 51 of the adjacent apparatus main body by the holding means. That is, as shown in FIG. 7B, the upper end surface 40c of the fixing cover 40 abuts against the abutting portion 50 of the apparatus main body, the arm 40b1 of the lock claw 40b is bent, and the lock claw 40b and the protrusion are formed. There is no gap between the portions 43a, and there is no play in the rotation direction of the fixing cover 40. Further, since the fixing cover 40 abuts against the abutting portion 50 of the main body, by providing the abutting portion 50 on the adjacent exterior cover 51, the step between the fixing cover 40 and the adjacent cover 51 can be minimized. it can.
[0027]
As described above, in the present embodiment, the fixing cover 40, which is an exterior cover that covers the attaching / detaching direction of the fixing unit 1, is formed integrally with the fixing unit 1, so that the fixing cover 40 is removed before the fixing unit 1 is removed. It is not necessary to remove the fixing unit, and the fixing cover 40 can be integrally attached to and detached from the fixing unit.
[0028]
Further, since the conveyance guide 40a is provided on the fixing cover 40 integrally formed with the fixing unit 1, the positional relationship between the conveyance guide 40a and the conveyance nip 7 immediately after fixing can be maintained with high accuracy. The transfer performance is improved.
[0029]
Further, since the fixing cover 40 integral with the fixing unit 1 is located at a position covering the intermediate conveyance roller 2, the intermediate conveyance roller 2 can be accessed by removing the fixing unit 1 or opening the openable cover. Accordingly, the jam removal property in the vicinity of the intermediate conveyance roller 2 is improved.
[0030]
Further, when the fixing cover 40, which can be opened and closed, has a holding means for holding a step with the adjacent cover 51 when the fixing cover 40 is closed, even if the fixing cover 40 is integrated with the fixing unit, the fixing device may be adjacent to the apparatus main body. The step with the cover 51 can be held.
[0031]
【The invention's effect】
Since the present invention is configured as described above, the outer cover covering the mounting / detaching direction of the fixing unit is integrally formed with the fixing unit, so that it is not necessary to remove the outer cover before removing the fixing unit. Since the unit can be detached integrally, the detachability of the fixing unit is improved.
[Brief description of the drawings]
FIG. 1 is an overall sectional explanatory view of an image forming apparatus.
FIG. 2 is an explanatory cross-sectional view of a fixing unit.
FIG. 3 is an explanatory perspective view of a fixing unit.
FIG. 4 is an explanatory perspective view of a fixing unit.
FIG. 5 is an explanatory diagram illustrating a state where the fixing unit is removed from the apparatus main body.
FIG. 6 is an explanatory diagram of a state where a cover is opened.
FIG. 7 is an explanatory view in which the relationship between a lock claw and a projection is simplified.
[Explanation of symbols]
S: Sheet 1: Fixing unit 2: Intermediate transport roller 3: Discharge roller 4: Face down tray 5: Heater 6: Pressure roller 7: Transport roller pair 8: Fixing film 9: Film guide 10: Guide 30: Laser scanner Reference Signs List 31 photoconductor drum 32 cassette 33 feed roller 34 transfer roller pair 36 registration roller pair 36 transfer roller 40 fixing cover 40a transfer guide 40b lock claw 40b1 arm 40c end surface 41 fixing lower cover 42 lock lever 43 fixing upper cover 43a projecting portion 50 abutment portion 51 exterior cover

Claims (7)

In an image forming apparatus that fixes a sheet carrying an unfixed image by a fixing unit and discharges the sheet to a discharge unit,
An image forming apparatus, wherein the fixing unit is configured as a unit that can be attached to and detached from the apparatus main body, and an exterior cover that covers the attaching / detaching direction of the fixing unit is integrally formed with the fixing unit. The image forming apparatus according to claim 1, wherein a guide unit that guides the sheet that has passed the fixing unit to the discharge unit is provided on the exterior cover. The image forming apparatus according to claim 2, wherein at least a part of the exterior cover is openable and closable with respect to the apparatus main body. 2. The image forming apparatus according to claim 1, wherein the sheet conveying path is exposed when the fixing unit is removed from the apparatus main body. 4. The image forming apparatus according to claim 3, wherein when at least a part of the exterior cover is opened with the fixing unit mounted on the apparatus main body, a sheet conveying path is exposed. 5. The exterior cover is openable and closable about a lower side of the exterior cover as a fulcrum. When the exterior cover is closed, the exterior cover is locked to the fixing unit near an upper side of the middle of the exterior cover, and the fixing unit is attached to the apparatus main body. 4. The image forming apparatus according to claim 3, further comprising: holding means for holding an abutting portion of the adjacent apparatus main body with the cover when the cover is closed. The holding means includes a lock mechanism including a lock claw provided on an openable / closable exterior cover and a member provided with a claw provided in the fixing unit, and a lock mechanism provided in the apparatus main body which abuts when the exterior cover is closed. 7. The locking claw according to claim 6, wherein the locking claw is bent when the fixing unit is mounted on the apparatus main body and the cover is closed. Image forming device.

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