JPH0645978Y2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an image forming apparatus including a fixing device having a pair of fixing rollers.

[Prior Art] Conventionally, an image forming apparatus having a structure in which a main body is divided into an upper unit and a lower unit at the time of paper jam, maintenance, and attachment / detachment of a process cartridge, and the upper unit can be opened with respect to the lower unit. Are known. Further, in such an image forming apparatus, a fixing unit composed of a pair of upper and lower rollers is provided, and in order to facilitate the removal of the transfer paper accumulated between the upper and lower rollers, the upper and lower rollers of the fixing unit are Some are equipped with a mechanism for releasing the pressure. As this pressure release mechanism, when the above unit is released, the pressure of the fixing unit is released in conjunction with this (Fig. 6), and a paper discharge door is provided on the paper discharge side of the apparatus, and this is opened. There is one that releases the pressure of the fixing unit in conjunction with.

However, such a pressure releasing mechanism holds the upper and lower rollers of the fixing unit in separate frames, and applies a contact pressure to the upper and lower rollers through this frame, which inevitably complicates the structure of the fixing unit. . Further, holding each of the upper and lower rollers on a separate frame has a problem in suppressing the positional relationship between the upper and lower rollers in terms of accuracy.

On the other hand, it takes a considerable amount of labor to remove the paper that is sandwiched between the upper and lower rollers without releasing the force, and the paper contacts the nip portion of the upper and lower rollers when the rollers are in pressure contact. However, since it is pulled out, there is a problem with dirt and wear of the roller.

[Purpose of device]

An object of the present invention is to provide an image forming apparatus capable of easily taking out the paper accumulated between the pair of fixing rollers without releasing the pressure of the pair of fixing rollers of the fixing unit and simplifying the main body structure. To provide.

[Outline of device]

The present invention for achieving the above object is an image forming apparatus having a main body that can be divided into two housings and a paper discharge door that can be opened and closed on the paper discharge side, and a fixing unit having a pair of fixing rollers. , The driving means for driving the fixing roller and the pressing operation of the pair of fixing rollers are held, and at least one of the dividing operation of the casing or the opening / closing operation of the discharge door is linked to at least one operation. And a means for releasing the drive from the driving means to the fixing roller. According to this, since the drive transmission from the driving means for driving the fixing roller is released, the fixing roller can be rotated when the paper is pulled out from between the fixing rollers and removed, thereby facilitating the paper jam processing. .

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall sectional view showing an embodiment of the image forming apparatus of the present invention. In the figure, reference numerals 1a and 1b respectively denote an upper unit and a lower unit which can be separated from each other, and form a casing of the main body device. The upper unit 1a can be opened upward with respect to the lower unit 1b about the axis. The upper unit 1a can be opened when the original table 5 is moved to the left as shown in the drawing. Also, the upper unit
1a has a minimum necessary size that enables paper jam processing and attachment / detachment of the well-known process cartridge 2. Further, for paper jam processing from the pair of fixing rollers 30 of the fixing device 3 to the paper discharge port, a paper discharge door 4 which can be opened and closed is provided at the paper discharge port and is opened in the arrow direction to remove the paper. is there. 40 is a paper discharge roller. Further, in the present invention, a mechanism for releasing the drive of the fixing device 3 to the pair of fixing rollers 30 is provided in association with at least one of the opening / closing operation of the upper unit 1 and the opening / closing operation of the paper discharge door 4. , Makes it easy to remove the paper accumulated between the rollers.

Next, an embodiment of this drive release mechanism will be described with reference to FIG.

6 is a drive gear for the fixing roller 30, 7 is an idler gear for transmitting drive, 8 is a gear for transmitting drive from the main body drive gear 9, and gears 7 and 8 are gear holding members 11 rotatable about a support shaft 10. It is installed. The main body drive gear 9 is a gear that is driven by a motor (not shown). Gear holding member
A spring 12 is attached to 11 and the other end of the spring 12 is a fixed end. At this time, the rotatable gear holding member 11 is a spring.
The gear 8 is biased by 12 so that the gear 8 meshes with the main body drive gear 9 about the support shaft 10. The drive transmission at this time is motor → gear 9 → gear 8 → gear 7 → gear 6, which is not shown, and the drive is transmitted to the fixing roller.

Here, the drive release levers 13, 14 are provided near the gear holding member 11.
Two are provided. The lever 13 forms a cam mechanism with a part of the upper unit 1a, and rotates in conjunction with the opening / closing operation of the upper unit 1a to swing the gear holding member 11. When the upper unit 1a is opened, the lever 13 rotates in the direction of A in FIG. 3 and a part of the gear holding member 11 (for example, the cut-and-raised portion 11a) is pushed to cause the gear holding member 11 to move.
3 rotates in the direction of B in FIG. 3, the gear 8 is separated from the main body drive gear 9, and the drive to the fixing roller is released. On the contrary, when the upper unit 1a is closed, the spring 12 automatically returns to the state shown in FIG.

On the other hand, the lever 14 forms a cam mechanism with a part of the paper discharge door 4, and the fixed shaft 14a engages with the elongated hole of the lever 14 so that the lever 14 can move. The lever 14 swings the gear 3 holding member 11 in conjunction with the opening / closing operation of the paper discharge door 4. As shown in FIG. 4, when opening the discharge door 4,
The lever 14 moves in the direction C, and a part 11b of the gear holding member 11
By pressing, the gear holding member 11 moves in the B direction, the gear 8 is separated from the main body drive gear 9 as in FIG. 3, and the drive to the fixing roller is released.

The levers 13 and 14 may be, for example, a lever 13 'that simply rotates as shown in FIG. 5 without forming a cam mechanism.

In any case, even if the fixing roller is still under pressure, the drive transmission to the fixing roller is linked with the operation of either the upper unit opening or the paper discharge door opening. Since it is released, the paper jam processing becomes easy.

[Effect of device]

As described above, according to the present invention, the paper jam processing can be performed only by releasing the driving without releasing the pressure of the pair of fixing rollers, so that the pressure releasing mechanism is not required, so that the structure is simplified and compact. Can be converted.

The risk that the user touches the area around the fixing roller is reduced and safety is increased.

Such an effect can be obtained.

[Brief description of drawings]

FIG. 1 is an overall cross-sectional view of an image forming apparatus according to an embodiment of the present invention,
FIG. 2 is a schematic view showing an embodiment of a drive releasing mechanism of the fixing device of the present invention, FIG. 3 is a schematic view showing a gear connecting portion when the upper unit is opened in FIG. 2, and FIG. FIG. 5 is a schematic view showing the gear connecting portion when the paper discharge door is opened in FIG. 2;
FIG. 6 is a schematic view showing another embodiment of a release lever not forming a cam mechanism, and FIG. 6 is a schematic view showing a state where the upper unit is opened to release the pressure of the upper and lower rollers of the fixing device. In the figure, 1a is an upper unit, 1b is a lower unit, 3
Is a fixing device, 4 is a sheet discharge door, 6 is a driving gear of a fixing roller, 7,
Reference numeral 8 is a gear, 9 is a main body drive gear, 11 is a gear holding member, 12 is a spring, 13 and 14 are drive release levers, and 30 is a pair of fixing rollers.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinji Kanemitsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Morichikazu Mizutani 3-30-2 Shimomaruko, Ota-ku, Tokyo Kiya Non-Co. Ltd. (56) Reference JP 60-166962 (JP, A) JP 60-32066 (JP, A) JP 60-102673 (JP, A) JP 62-47678 (JP , A)

Claims (1)

[Scope of utility model registration request] 1. An image forming apparatus having a main body that can be divided into two housings and having a paper discharge door that can be opened and closed on the paper discharge side, and a fixing unit having a pair of fixing rollers, and the fixing roller. And a drive means for driving the drive means and the drive means in association with at least one operation of the division operation of the casing or the opening / closing operation of the paper discharge door while maintaining the pressurization state of the pair of fixing rollers. And a means for releasing the drive from the fixing roller to the fixing roller.