JPH11296009A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of surely exchanging a fixing device, minimizing the device, and preventing a misoperation when a user exchanges the fixing device. SOLUTION: A front cover 21 is rotatably provided in a main body frame 30 of the image forming device. When the front cover 21 is opened to exchange a fixing unit 11 for instance, an arm 31 keeps the fixed position of the front cover 21. In the case where the fixing unit 11 is exchanged, the front cover 21 is opened, a fixing locking lever 23 is lowered and the fixing unit 11 is pulled, to easily remove it. When the fixing unit 11 is pulled, a fixing device projection 11a is separated from a shield plate 34 and it is turned by gravity and fixed by a stopper 30c. In this state, even if the user tries to close the front cover 21, the shield plate 34 hits against the top end 31a of the arm, not to release interlocking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser printer, a copying machine, a facsimile, etc., having a detachable fixing unit. The present invention relates to an image forming apparatus having a prevention mechanism.

[0002]

2. Description of the Related Art Generally, the life of a laser printer or the like is 600K to 1000K, whereas the life of a fixing device is deteriorated by heat of a fixing roller or a pressure roller, paper dust, paper dust, or the like. Due to the decrease in the fixing property due to the toner adhesion, the number of sheets becomes about 100K sheets, and if the life of the fixing device is increased, the cost increases. for that reason,
During the life of the fixing device, the replacement of the fixing device by a service engineer will occur.However, with recent laser printers, etc., due to the increase in the number of units sold due to downsizing and personalization of the user, it is difficult for service personnel alone to respond. Is coming. For this reason, in recent years, instead of the conventional maintenance performed by a service person, there is an increasing number of users who perform maintenance by themselves.

For this reason, it is desired that the configuration of the fixing device be easily replaced in units of units in consideration of maintenance by a user (for example, see Japanese Patent Application Laid-Open No.
In such a case, if the unit is to be housed in the apparatus body as a unit, the entire apparatus tends to be large in size. The setting place has to be considered.

SUMMARY OF THE INVENTION In view of the above problems, the present invention ensures the exchangeability of a fixing device, minimizes the number of fixing devices in which a user can replace the fixing device, and replaces the fixing device with a user. It is an object of the present invention to provide an image forming apparatus capable of preventing an erroneous operation at the time.

According to the image forming apparatus of the present invention, in order to achieve the above object, the locus is regulated by a fixing unit which can be replaced by a user and a guide hole provided in a frame of the apparatus main body. An image forming apparatus comprising: a front cover provided with an arm; and an interlock means for identifying whether the front cover of the apparatus main body is opened or closed by the arm, wherein the arm inhibits the operation of the arm in conjunction with the fixing unit. It is characterized by having an operation preventing means.

According to a second aspect of the present invention, the arm operation preventing means does not prevent the operation of the arm when the fixing unit is mounted on the apparatus main body, and the fixing unit is connected to the apparatus main body. When the arm is not mounted, the arm is prevented from operating, and display means is provided for indicating that the fixing unit is not mounted on the apparatus main body.

According to a third aspect of the present invention, the interlock means turns on the interlock switch by pressing the arm, and always turns off the interlock switch when it is not pressed by the arm. And a rotatable cam.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view conceptually showing the overall structure of a laser printer which is an image forming apparatus utilizing an electrophotographic process. In this apparatus, a photoconductor 2 is provided at a substantially central portion in a main body case 1, and a charger 3, a developing device 4, a transfer device 5, a cleaning device 6 are provided around the photoconductor 2.
Etc. are arranged. Further, below the photosensitive member 2 and the like, a paper feed roller 9 for feeding the recording paper stored on the bottom plate 8 of the paper feed tray 7 one by one, and the fed recording paper is transferred to the transfer device 5 at a predetermined timing. There is provided a registration roller 10 and the like for sending out the sheet. Further, a fixing unit 1 for fixing the image transferred to the recording paper in the transfer device 5 is provided above the photoconductor 2 and the like.
1 and a paper discharge roller 12 for discharging the recording paper on which the image has been fixed.

A stacker unit 13 for discharging recording paper on which an image has been formed is formed on the upper surface of the main body cover 1a which is a part of the main body case 1. This stacker unit 13
The electrical component 15 is housed in a metal case 14 below the box. The electrical unit 15 includes a controller board 16 and various adjustment switches and control units (not shown) mounted on the control board 16. Further, a power supply 17 and an electrical board 18 are housed in the metal case 14, and an optical device 20 for writing an image on the photoconductor 2 is provided above the power supply 17 and the electrical board 18.

A front cover 21 is provided on a part (right side in the figure) of the main body case 1. A transfer device 5 and a neutralizing brush (separating means) 22 are attached to the front cover 21 and can rotate about a part of the main body case 1 as a fulcrum. It is configured so that processing at the time of paper jam or the like can be performed.

FIG. 2 is an enlarged sectional view showing the entire structure of one embodiment of the present invention. The reference shafts 11 b and 11 c of the fixing unit 11 enter the reference portions of the main body frame (side plate) 30, and the fixing unit 11 is fixed to the main body frame 30 by the fixing lock lever 23. Body frame 30
Is provided with a fulcrum of the front cover 21 described above, and the front cover 21 is rotatable.
1 is provided with a rotation fulcrum of the arm 31.

The end of the arm 31 is inserted into a guide hole 30a of the main body frame 30, and its trajectory is regulated by the guide hole 30a. That is, when the front cover 21 is closed, the arm tip 31a pushes the projection 32a of the interlock cam 32, so that the interlock cam 32 rotates in the direction of the arrow in FIG. I have to. A shielding plate 34 is provided on the main body frame 30, and when the fixing unit 11 is fixed, the shielding plate 34 is pushed by the fixing device projection 11 a and takes a position that does not interfere with the arm 31. . In the figure, 30b is a shielding plate 34
Is an interlock switch arm.

FIG. 3 is an enlarged sectional view showing a state in which the operation of the arm 31 is blocked in conjunction with the fixing unit 11. When the front cover 21 is opened (jam clearing, supply replacement, replacement of the fixing unit 11, etc.), the arm 31
It also has the function of maintaining (supporting) the fixed position of. When replacing the fixing unit 11, the front cover 21 is rotated and opened in the direction of arrow A shown in the figure, the fixing lock lever 23 is lowered in the direction of arrow C in the figure, and the fixing unit 11 is pulled in the direction of arrow B in the figure. Can be easily removed. When the fixing unit 11 is pulled in the direction of arrow B, the fixing device projection 11a is separated from the shielding plate 34, and the shielding plate 34
Rotate in the direction (rotation by its own weight). And the shielding plate 34
Is fixed at a position shown in the figure by a stopper 30c. When the front cover 21 is closed without the fixing unit 11, the interlock cannot be turned on because the shielding plate 34 and the arm tip 31a hit.

FIG. 4 is an enlarged sectional view showing a state in which the operation of the arm 31 is blocked and a message indicating that the fixing unit 11 is not mounted is displayed. The filler 34a formed integrally with the shielding plate 34 turns off (or turns on) the photo-interrupter 35 provided on the main body frame 30 when the fixing unit 11 is not mounted. LCD
A warning is displayed (or an LED is turned on). This notifies the user that the fixing unit 11 is not mounted.

FIG. 5 is an enlarged sectional view showing details of the operation of the interlock means. As the front cover 21 is opened, the arm 31 also moves rightward in the drawing. As the arm tip 31a moves away from the interlock cam projection 32a, the interlock cam 32 is moved by the force of the interlock switch arm 33a (a normal microswitch or the like has a return force of about 150 gf) in the direction of arrow E in the figure. At the position of the stopper 30c, and the interlock switch 33 has already been turned off at this time. As shown in FIG. 2, when the arm tip 31a is pressed by the arm tip 31a, the arm tip 31a and the interlock cam projection 32a are in a parallel state. The position does not change, interlock switch 3
3 can be turned on at a stable position without causing a load and component damage. Further, since the interlock cam 32 is rotated by the pressing force of the interlock switch arm 33a, even if the arm tip 31a is damaged, the interlock switch 33 is always turned off, and safety can be ensured. Although a configuration in which the interlock switch arm 33a is directly pressed by an arm or the like is also conceivable, it is necessary to consider that a state such as breakage of a component or a state in which a switch is not turned on may occur depending on a pressing position and a pressing amount due to variation in components.

[0016]

As described above, the image forming apparatus according to the first aspect has a front cover including a fixing unit that can be replaced by a user and an arm whose trajectory is regulated by a guide hole provided in a frame of the apparatus main body. Since the arm has interlock means for identifying the open / closed state of the front cover of the apparatus main body and the arm operation inhibiting means for interlocking with the fixing unit to prevent the operation of the arm, By preventing the user from erroneous operation due to the absence of the unit, the exchangeability of the fixing unit is ensured, and the simple configuration is sufficient, so that the apparatus can be minimized in a configuration in which the user can replace the fixing unit. effective.

In the image forming apparatus according to the second aspect, as described above, the arm operation preventing means does not prevent the operation of the arm when the fixing unit is mounted on the apparatus main body. Since the operation of the arm is prevented when the fixing unit is not attached to the main body, and a display unit indicating that the fixing unit is not attached to the apparatus main body is provided. There is an effect that the user is informed in advance that there is no such information, a visual sense of security is provided, and unnecessary operations are not performed.

In the image forming apparatus according to the third aspect, as described above, the interlock means turns on the interlock switch by pressing the arm, and always interlocks when the arm is not pressed by the arm. Since there is a rotatable cam for turning off the switch, in addition to the above-mentioned common effects, there is an effect that the safety of the interlock means is enhanced and the safety of the user is also enhanced.

[Brief description of the drawings]

FIG. 1 is a sectional view conceptually showing the overall structure of a laser printer which is an image forming apparatus using an electrophotographic process.

FIG. 2 is an enlarged cross-sectional view showing the overall configuration of one embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing a state in which the operation of an arm is blocked in conjunction with a fixing unit in the embodiment of FIG. 2;

FIG. 4 is an enlarged cross-sectional view showing a state in which the operation of the arm is blocked in the embodiment of FIG. 2 and a message that the fixing unit is not mounted is displayed.

FIG. 5 is an enlarged sectional view showing details of an operation of an interlock means in the embodiment of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body case 1a Main body cover 2 Photoreceptor 3 Charger 4 Developing device 5 Transfer device 6 Cleaning device 7 Feed tray 8 Bottom plate 9 Feed roller 10 Registration roller 11 Fixing unit 11a Fixing device protrusion 11b, 11c Reference shaft of fixing unit 12 Discharge roller 13 Stacker unit 14 Metal case 15 Electrical unit 16 Controller board 17 Power supply 18 Electrical board 20 Optical device 21 Front cover 22 Static elimination brush (separation means) 23 Fixing lock lever 30 Main frame (side plate) 30a Guide for main frame Holes 30b, 30c Stopper 31 Arm 31a Arm tip 32 Interlock cam 32a Interlock cam projection 33 Interlock switch 34 Shielding plate 33a Interlock switch arm 34a Filler 35 Photo interrupter

Claims (3)

[Claims] 1. A fixing unit having a user-replaceable fixing unit and a front cover having an arm whose locus is regulated by a guide hole provided in a frame of the apparatus main body, wherein the front cover of the apparatus main body is opened and closed by the arm. An image forming apparatus provided with an interlock means for identifying the image forming apparatus, wherein the image forming apparatus further comprises an arm operation preventing means for preventing the operation of the arm in conjunction with the fixing unit. 2. The arm operation preventing means does not prevent the operation of the arm when the fixing unit is mounted on the apparatus main body, and when the fixing unit is not mounted on the apparatus main body. 2. The image forming apparatus according to claim 1, further comprising a display unit that prevents the operation of the fixing unit and that the fixing unit is not mounted on the apparatus main body. 3. The interlock means turns on an interlock switch by pressing the arm,
3. The image forming apparatus according to claim 1, further comprising a rotatable cam that always turns off said interlock switch when not pressed by said arm.