JPS6255151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device used in an image forming apparatus.

An explanation will be given below using an electrophotographic copying machine as an example.

[Prior art and its problems]

As a fixing device for an electrophotographic copying machine, a roll fixing device is well known, which heats and fixes a toner image on copy paper by passing the copying machine between a pair of rolls. The method of separating the copy paper from the roll includes a method of separating the copy paper by jetting an air flow between the roll and the copy paper, a method of separating the copy paper by suction,
Alternatively, a method of separating using separation claws has been proposed. However, among these methods, the method of separating using separation claws has the simplest structure and can reliably separate the copy paper from the roll.

By the way, the above-mentioned fixing device is normally located just before the copy paper processed in the electrophotographic copying machine is discharged from the copying machine due to its configuration and usage. Therefore, in addition to paper jams due to poor separation in the fixing device itself, paper jams in the fixing device can also occur due to troubles in the feeding, transfer, and conveyance paths of the copy paper, or problems with the copy paper. As described above, paper jams often occur in the fixing device, and therefore, the jam processing (jam processing) is frequently performed.

Here, an example of a conventional fixing device is shown in FIG. 1 and will be described.

In the figure, a heating roll 1 is placed on the copy paper conveyance exit side.
A conveying paper guide 7 is provided in close proximity to a separating claw 4 that is in pressure contact with and is rotatable around a fixed shaft 5, and a pressure roll 3. 2 is an infrared heater that heats the heating roll 1. Furthermore, the separating claw 4 is required to have good heat resistance, abrasion resistance, and sliding properties, and generally, the tip of the claw is thin and sharp in order to separate the copy paper that is trying to adhere to the heating roll. ing. Note that 7, 8, and 9 are paper guides, and 10 is a discharge roll. Here, paper jams in the fixing device occur when the copy paper wraps around the heating roll 1 that is in contact with the sticky toner image on the copy paper, or when the copy paper is pinched between the separation claw 4 and the heating roll 1 and presses the separation claw 4. The state will be as follows.

Therefore, conventionally, as shown in FIG. 1, the separating claws 4 are held rotatably with respect to the axial direction of the heating roll 1, and when paper is pressed during a paper jam, the separating claws 4
Some devices are configured to rotate around the fixed shaft 5 to avoid the pressure. This configuration is effective in protecting the separating claws in the event of a paper jam. However, when dealing with a paper jam, the separation claw 4 is present in the paper jam disposal area and becomes an obstacle to paper jam disposal. Furthermore, since the fixing device itself is heated to a high temperature due to preheating of the heating roll 1, it is difficult to dispose of paper jams, and the separating claws are often damaged or deformed, causing new paper jams.

[Object of the present invention]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a fixing device which eliminates the problems of the conventional apparatus, does not damage the separating claw during jam processing, and is easy to perform jam processing.

[Configuration of the present invention]

That is, to briefly describe the first and second inventions of the present invention that achieve the above object, both the first invention and the second invention include a pair of fixing rolls, a separation claw, and a sheet material that has passed through the pair of rolls between them. The fixing device has an upper conveying section and a lower conveying section, and the main point of the first invention is that there is a cover that can be opened and closed by rotating around a hinge, and that the separating claw and the upper conveying section are connected to this cover. The cover is supported by the separating claw and the upper conveyance part and is rotated to open and close around the hinge.The main point of the second invention is that the separating claw can be rotated about the rotation axis. The rotating shaft is supported by the cover, and therefore the separating claw also rotates as the cover rotates open and close about the hinge, but in the second invention, the cover further rotates. The present invention has a separating claw displacement means that rotates the separating claw around the rotation axis to bring the separating claw into contact with and away from the roll surface when the roller is opened and closed.

[Example of the present invention]

Embodiments of the present invention will be described below with reference to FIGS. 2, 3, and 4.

FIG. 2 is a sectional view of a fixing device to which an embodiment of the present invention is applied.

In the figure, an infrared lamp 1 for heating inside
1 and a pressure roller 13, which presses against the roller 12 and forms a nip, rotate in the direction of the arrow to fix the toner image on the copy paper.
A separation claw 1 is provided on the copy paper delivery side of this heating roller 12.
A plurality of rollers 4 are rotatably disposed on a shaft 15 and pressed against the surface of the heating roll 12 by a spring 16. The copy paper separated by the separation claw 14 passes between the upper and lower transport sections 17 and 18 and is stored in the tray 24. The shaft 15 and the upper conveyance section 17 are fixed to a cover 19 which also serves as heat insulation, and the cover 19 is rotatable around a hinge 20. In addition, in the figure, 18' is a guide.

Further, using FIG. 3, explanation will be given on handling paper jams.

First, when the handle 21 provided on the cover 19 is pulled in the direction of the arrow, the shaft 21 fixed on the cover 19
The handle 21 rotates around . Therefore, the handle 21 is released from the fixing dowel 23 on the fuser main body, and
The cover 19 is rotatable around the hinge 20.

Here, since the handle 21 is connected to the separation claw 14, the rotation of the handle 21 in the direction of the arrow causes the separation claw 14 to rotate around the shaft 15 and separate from the surface of the heating roll 12 as shown in FIG. Separate. Next cover 1
When the cover 19 is rotated around the hinge 20 and opened, the cover 19 supports the shaft 15 that supports the separation claw 14 and the upper conveyance section 17. Cover 19 in the center
Rotate and move with the In other words, as shown in FIG. 4, the separating claw 14 is in contact with the heating roll 12 at a position separated from the separating position where the copy paper is separated from the heating roll 12. This provides sufficient space for clearing paper jams by moving to a position away from the copy paper conveyance position opposite to the copy paper transport position. Therefore, not only is it easy to perform jamming, but also there is no risk of damaging the separating claws during the jamming operation since there are no separation claws in the jamming area.

Further, as described above, when opening the cover 19, the separating claws 14 are rotated around the shaft 15 to separate them from the surface of the heating roll 12, and then the separating claws 14 are moved away from the cover 19.
Since the copy paper is rotated around the hinge 20, the copy paper is separated between the heating roll 12 and the separating claw 1.
Even in a state where the paper is jammed and an excessive force is applied to the separation claw 14, the separation is easier than when the separation claw 14 is suddenly rotated around the hinge 20 and moved. The load on the claws 14 is reduced, and deformation and damage to the separation claws 14 can be further prevented.

Next, after the jamming process, the cover 19 is returned to its original position, and the handle 21 is rotated in the opposite direction to lock into the dowel 23. Here, when the cover 19 is closed, the separating claw 14 rotates around the hinge 20, and instead of suddenly returning to the position where it contacts the roll 12, it temporarily separates from the roll 12 as shown in FIG. It rotates around the hinge 20 and returns to the position, and then rotates around the shaft 15 in conjunction with the action of locking the handle 21 to the dowel 23 and moves the roll 12
, the separation claw 14 rotates vigorously around the hinge 20 and collides with the roll 12, causing damage.
It can prevent deformation.

In the embodiment described above, the separation claw displacement means rotates the separation claw 14 about the shaft 15 in connection with the opening/closing operation of the cover 19 to contact and separate the separation claw from the heating roll 12. Although this is done in conjunction with the locking mechanism of the cover, it may also be done in conjunction with the opening/closing operation of the cover using a link mechanism, solenoid, or the like.

〔Effect of the invention〕

As can be seen from the above description, in the first invention, sufficient space for jam processing can be obtained by rotating the separating claw and the upper conveyance section together with the cover, so that the operability of jam processing is improved, and There is no fear of damaging the separation claw during jam processing.

Further, in the second invention, in addition to the effects of the first invention, when opening and closing the cover, the separation claw is rotated around the separation claw rotating shaft supported by the cover to contact and separate from the roll. This has the effect of further preventing breakage and deformation of the separation claw during the process.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional fixing device, and FIGS. 2, 3, and 4 are sectional views of a fixing device to which the present invention is applied. In the figure, 1... heating roll, 2... infrared heater, 3... pressure roll, 4... separating claw, 5...
Fixed shaft, 6... Spring, 7, 8, 9... Conveying paper guide, 10... Carrying out roll, 11'... Copying paper, 1
1... Infrared heater, 12... Heating roll, 13...
... Pressure roll, 14 ... Separation claw, 15 ... Fixed shaft, 16 ... Spring, 17, 18 ... Conveyance section, 19
...Cover, 20...Hinge, 21...Handle, 2
2... shaft, 23... dowel, 24... tray.

Claims (1)

[Claims] 1. A pair of rolls that rotate in pressure contact with each other, a separation claw provided on the upper roll of this pair of rolls to separate the sheet material from the roll surface, and a separation claw that separates the sheet material that has passed through the pair of rolls. A fixing device that has an upper and a lower conveyor section that convey the sheet material between the pair of rolls, and fixes the toner image on the sheet material by passing the sheet material between the pair of rolls, a shaft that supports the separating claw, and an upper conveyor section. and a cover that can be opened and closed by rotating around a hinge while supporting the shaft supporting the separation claw and the upper conveyance section, and when the cover is closed, the separation claw is located in a separation position where it abuts the roll surface, and the upper conveyance section is located in a conveyance position opposite the lower conveyance section, and when the cover is opened, the separation claw and the upper conveyance section engage the hinge. The fixing device is characterized in that the fixing device rotates together with the cover at the center and moves to positions separated from the separation position and the conveyance position, respectively. 2. A pair of rolls that rotate in pressure contact with each other, a separation claw that is provided on the upper roll of this pair of rolls and that separates the sheet material from the roll surface, and an upper part that transports the sheet material that has passed through this pair of rolls between them. a lower conveyance section, a fixing device that fixes the toner image on the sheet material by passing the sheet material between the pair of rolls; a separation claw rotating shaft that rotatably supports the separation claw; a cover that supports the separation claw rotating shaft and the upper conveyance section and can be opened and closed by rotating around a hinge while supporting the separation claw rotation shaft and the upper transfer section; When the cover is opened and closed, the separation claw is rotated about the separation claw rotating shaft to separate it from the roll surface, and when the cover is closed, the separation claw is rotated about the separation claw rotation axis in connection with the opening and closing operation of the cover. separation claw displacement means for rotating the claw around the separation claw rotating shaft and bringing the claw into contact with the roll surface, and when the cover is closed, the separation claw comes into contact with the roll surface. The upper conveying section is located in a separating position facing the lower conveying section, and when the cover is opened, the separating claw and the upper side are separated from the roll surface by the separating claw displacement means. The fixing device is characterized in that the conveyance section rotates together with the cover about the hinge and moves to a position separated from the separation position and the conveyance position, respectively.