JPH01276183A - Fixing device - Google Patents

Abstract

PURPOSE:To send a form correctly even if the form varies in thickness, rigidity, etc., by winding a form conveyor belt around one of two rolls which are pressed against each other. CONSTITUTION:The heat roll 10 and pressure roll 11 are pressed against each other to form a fixing unit. This roll 11 is wound with the form conveyor belt 13, which extends to the exit-side roll 16 and tension roll 17 of a transfer part 15 for a photosensitive material 14 and is driven and rotated in synchronism with the rolls 10 and 11. Consequently, the form 20 where an unfixed toner image 19 is formed is carried by the belt 13 and sent to the nip part 12a between the rolls 10 and 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fixing device that is used in electrophotographic copying machines and the like and is composed of two rolls, such as a heating roll and a pressure roll.

[Conventional technology]

For example, the fixing device shown in FIG. 3 is known as a fixing device formed by pressing two rolls into contact with each other.

That is, as shown in FIG. 3, a fixing device 3 is known which includes a heating roll 1 and a pressure roll 2, and this fixing device 3 is disposed facing a transfer section 5 of a photosensitive material 4. The paper 7 on which the unfixed toner image 6 has been formed in the transfer section 5 is sent to the nip section 3a from the conveyance guide 9 through a conveyance path 8 such as a vacuum transport, and as it passes through the nip section 3a, the unfixed toner image is removed. , the toner image 6 is heated and pressurized to fix it.

In the fixing device 3 consisting of the heating roll 1 and the pressure roll 2, it is necessary to feed the paper 7 into the nip part 3a in the correct posture. The paper 7 is disposed facing upward, and the paper 7 that has passed through the conveyance guide 9 is fed straight into the nip 3a by hanging down.

[Problem to be solved by the invention]

In such a fixing device, the paper 7 is correctly fed into the nip portion 3a by the transport guide 9 as described above, but the thickness and stiffness of the paper 7 may change, or the transport guide 9 may change. If there is a placement error, the paper 7 should be moved to the nip section 3.
Since the paper may not be fed in the correct orientation and wrinkles may occur, it may result in poor fixing.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fixing device that can correctly feed paper even if the thickness, stiffness, etc. of the paper change.

[Means and operations for solving the problem] A paper conveyance belt is wound around one of the two rolls that are pressed into contact with each other, so that the paper can be reliably fed into the nip portion by this paper conveyance belt. .

〔Example〕

As shown in FIG. 1, a heating roll 10 and a pressure roll 11
are pressed against each other to form a fixing device 12, and a paper conveyance belt 13 is wound around this pressure roll 11, and this paper conveyance belt 13 is disposed on the exit side of the transfer section 15 of the photosensitive material 14. It is wound around the roll 16 and the tension roll 17, and is configured to rotate in synchronization with the heating roll 10 and the pressure roll 11.

The heating roll 10 has a heater 10b disposed inside a metal cylindrical roll lOa, and is connected to a drive source (not shown), and the pressure roll 11 has a metal core material 1.
A rubber layer 11b made of heat-resistant fluororubber, silicone rubber, etc. is attached to the surface of the paper transport belt 1a, and the paper conveyance belt 13 has approximately the same width as the heating rolls 10 and 11. is pulled in the belt tension direction by a spring 18 to apply tension to the paper conveyance belt 13.

Note that the heating roll 10 and the pressure roll 11 may be arranged upside down and the paper conveyance belt 13 may be wrapped around the heating roll 10, or the pressure roll 11 may have a built-in heater. .

As such, the paper 20 on which the unfixed toner image 19 has been formed after passing through the transfer section 15 of the photosensitive material 14 is conveyed by the paper conveyance belt 13 and fed into the nip section 12a between the heating roll 10 and the pressure roll 11. It will be done.

Therefore, even if the paper thickness and stiffness are different, the paper 2
0 can be reliably fed into the nip portion 12a without causing wrinkles.

Further, when the paper conveyance belt 13 passes through the nip portion 12a, it receives heat from the heating roll 10 and is heated and mixed.
Since the paper 20 that has passed through the transfer section 15 can be heated when it is conveyed to the nip section 12a, the fixing operation can be performed reliably.

That is, during the fixing operation, the unfixed toner image 19 is heated and the entire paper 20 is heated at the same time, and a large amount of heat is consumed in heating the paper, making the fixing operation unstable. Nip part 12 with 20 heated.
If the sheet is fed to the position H, the heat required to heat the sheet 20 is reduced, and the fixing operation can be performed stably and reliably.

Incidentally, in order to heat the paper 20, an auxiliary heater 21 may be provided as shown in FIG.

It can also be applied to a fixing device that applies pressure and fixes by pressing two rolls together and passing through a nip between the rolls.

〔Effect of the invention〕

Since the paper conveyance belt 13 rotates through the nip between the two rolls, the paper 20 can be fed into the nip by the paper conveyance belt 13, and sheets of different thickness and stiffness can be delivered straight into the nip. The fixing operation can be ensured because it can be fed in the correct posture without causing creases.

In addition, when the heating roll 10 is used, the paper conveyance belt 13 is heated when passing through the nip, so the nip portion 1
Since the paper fed to 2a can be heated, a stable fixing operation can be performed.

[Brief explanation of the drawing]

FIG. 1 is an overall explanatory diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of an applied example, and FIG. 3 is an explanatory diagram of a conventional example. 10 is a heating roll, 11 is a pressure roll, 12 is a fixing device,
12a is a nip portion, and 13 is a paper conveyance belt.

Claims (2)

[Claims] (1) A fixing device in which two rolls are pressed into contact with each other, and a paper conveyance belt 13 is wound around one of the rolls. (2) A heating roll 10 and a pressure roll 11 are brought into pressure contact to form a fixing device 12, and a paper conveyance belt 13 is wound around either the heating roll 10 or the pressure roll 11. Fusing device.