JPS5994772A - Dry type fixing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a pair of fixing rollers that nip and convey a transfer material carrying an unfixed toner image for fixing, and a means for supplying an anti-offset agent to at least one of the rollers. The present invention relates to a dry fixing device that includes a fixing port nib and a guide plate that guides the peeled transfer material to a discharge section on the downstream side of the fixing position.

Most of the conventional heat roller type fixing devices coat the heat roller with an anti-offset agent (hereinafter referred to as oil) such as silicone oil to prevent offset and improve the Lj type property. For this reason, oil accumulates at the tip of the peeling claw, which is provided downstream of the fixing position so that the tip touches the roller in order to separate the transfer material after fixing, and every time the transfer material passes, oil adheres to it and contaminates it. There were drawbacks. As a countermeasure for this,
Attempts have been made to prevent oil from accumulating on the tip of the pawl by providing a recess at the tip of the pawl, or by moving the pawl onto a roller.

However, the method of creating indentations in the pawl cannot prevent oil from accumulating between the pawl and the roller at the contact point due to the surface tension of the oil, and the method of moving the pawl onto the roller causes scratches on the roller. There are concerns that

OBJECTS It is an object of the present invention to provide a fixing device which eliminates the above-mentioned drawbacks of the conventional dry fixing device of the above type and which does not stain copies with oil accumulated at the tips of the nails.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail based on drawings showing embodiments thereof. In the embodiment shown in FIG. 1, a pressure roller 3 is pressed against a heating roller 1 containing a heat source 2 with an appropriate pressing force. The oil stored in the anti-offset liquid reservoir 4 is sucked up by the coating felt 5, and an appropriate amount is applied to the surface of the heating roller 1 via the coating roller 6.7.

This amount is selected to be suitable for preventing offset and releasability from paper.

Both rollers 1. Peeling claws 8 whose tips are in contact with B,
9 are provided rotatably about fulcrums 15 and 15', respectively. The peeling claws 8 and 9 are biased by springs 18 and 18' in a direction in which the tips of the claws come into pressure contact with the rollers 1 and 6.
Further, as shown in FIG. 6 (FIG. 6 shows only the separation claw 8. The same applies to the separation claw 9), the solenoid 1
9 engages with an engaging pin 22 provided at one end of a lever 20 that rotates about a shaft 21, so that the toe of the peeling claw 8 is retracted from the roller 1 when the solenoid is energized.

Conveyance guide plates 11 and 13 are provided facing the paper discharge rollers 16 and 17 across the path of the paper to be separated by the separation claws 8 and 9. Conveyance guide plate 1 facing the tip of the peeling claw 8
As shown in detail in FIG. 2, the felt 12 has a cutout at a portion corresponding to the peeling claw 8, and a felt 12 is installed on the back side of the conveyance guide plate 11, and is visible through the cutout. Similarly, the guide plate 16 facing the peeling claw 9 also has a peeling claw 9.
A cutout is provided in a portion corresponding to the cutout, and the felt 14 (FIG. 1) provided on the back side of the cutout is visible. As mentioned above, the peeling claw 8 is in the position retracted from the roller by the solenoid.
, 9 are in contact with the ferrules 12 and 14 (see Figure 2).

Since this device is configured as described above, the fixed transfer paper is separated and conveyed from the roller 1 or 6 by the peeling claw 8 or 9, and when the trailing edge has finished passing through the fixing section, the peeling claw 8
, 9 rotates around the fulcrum 15.15', and the tip of the toe contacts the felt (12.14), and the oil accumulated on the tip of the toe is absorbed and wiped off by the felt (12.14).

When the next transfer material comes into contact with the fixing roller, the solenoid 19 is turned off and the peeling claws 8 and 9 are returned to the position where their tips touch the rollers 1 and 6, but the tips of the peeling claws 8 and 9 are covered with oil. Since the transfer material has been removed, □ the transfer material is conveyed to the paper ejection rollers 16 and 17 without being contaminated.

When the transfer material 10 passes, the peeling claws 8 and 9 are moved by the spring 18 to the roller 1. Being pressured by Party B.

When the release signal enters the solenoid 19, the solenoid turns on and the tips of the peeling claws 8 and 9 retreat from the 0-ra 1 and 3.
Fell) 12. The oil that collects on the toe in contact with 14 is absorbed by this.

When the next transfer material comes to the fixing position, the solenoid is turned off, and the peeling claws 8 and 9 are moved again to the roller 1. Self (-to come into contact with.

The timing for releasing the pressure between the peeling claws 8 and 9 is such that the pressure is released until the transfer material comes into contact with the fixing roller.
The peeling claw may come into contact with the roller only when the transfer material passes through the fixing position 1a, and the peeling claw may be released again when the transfer material passes.

However, if the peeling claw comes into contact with the fixing roller while it is rotating, there is a risk of scratches on the roller surface.
The release signal for the peeling claw is input just before the rotation stop signal for the roller is input, and the peeling claw is held in the released state until the rotation of the fixing roller has completely stopped. After the fixing roller has completely stopped, the release claw is It is recommended that the roller be in contact with the roller.

If the release signal is input not just before the fixing roller rotation stop signal, but before that, the peeling claw must come into contact with the fixing roller while it is rotating. In other words, if the cancel signal is input immediately before, even if the copy start signal is turned on during that time, the copy start signal is canceled. This prevents oil from adhering to the transfer paper and staining it, and also prevents toner from adhering to the tip of the peeling claw, which hardens and causes scratches on the roller.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a side view illustrating displacement of a peeling claw in the embodiment, and FIG. 3 is a side view showing an example of a releasing mechanism for the peeling claw. . 1.6...Fixing roller pairs 4-7...Offset prevention agent supply means 8.9...Peeling claw 10...Transfer material 11.16...Guide plate 12.14...Offset prevention Agent for agent-absorbing materials Patent attorney Takehisa Ito

Claims (4)

[Claims] (1) A pair of constant speed rollers that nip and convey a transfer material carrying an undetermined bird toner image and perform fixing, a means for supplying an anti-offset agent to at least one of the rollers, and at least a pair of rollers on the downstream side of the fixing position. In a fixing device having a peeling pawl whose tip is in contact with one of the rollers, and a guide plate that guides the peeled and fixed transfer material to the discharge section, the peeling pawl can be brought into contact with and separated from the roller. At the same time, an anti-offset agent absorbing member is provided on the back side of the guide surface of the guide plate so that it can be seen from the guide surface, so that when the stripping claw A is separated from the roller, the tip of the stripping agent claw comes into contact with the absorbing member. A fixing device characterized by: (2) As set forth in claim 1, wherein two peeling claws are provided at different positions so as to be able to approach and separate from both rollers of the pair of fixing rollers, and an agent absorbing member thereof is provided. fixing device. (3) The above-mentioned peeling claw is characterized in that the tip of the peeling claw contacts the fixing roller only when the transfer material contacts the fixing roller in synchronization with the movement of the transfer material. The fixing device according to item 2. (4) The above-mentioned peeling claw is displaced to a position where its tip contacts the above-mentioned absorbing member (=displaced) slightly before the fixing roller rotation stop signal is input, and after the fixing roller rotation stops, it is returned to a position where it contacts the fixing roller, and during that time The fixing device according to claim 1 or 2, wherein the fixing roller rotation start signal is not input.