JPH0293675A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent a backup roll from being damaged even while disposing a separation claw which peels off recording paper stucked on the backup roll by providing the separation claw. CONSTITUTION:The recording paper 12 which is heated and pressed is apt to stick on a backup roll 13, but the recording paper 12 is peeled off by the part of a projection part 16a as a separating piece which projects from the surface of the backup roll and carried along a guide plate 16. The recording paper 12 is further carried by a backup roll 14, where the paper is heated, pressed, and discharged. At this time, the discharged recording paper is peeled off by the part of the projection part 16b being separating piece which projects from the surface of the backup roller. Thus, the recording paper 12 is fixed without sticking on the backup rolls 13 nor 14 and neither the backup roll is damaged by the separation claw.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a dry developer fixing device used in electrophotographic recording devices and the like.

2. Description of the Related Art A conventional fixing device is constructed as shown in FIGS. 3 and 4, in which 1 is a toner, 2 is a recording paper to which the toner 1 is attached in an unfixed state, and 3 is a halogen lamp inside. (not shown), the surface of which has been treated with fluororesin, and is configured to rotate in the A direction. Numeral 4 is a cleaner that removes toner adhering to the heat roller 3, and 5 is a backup roller that presses the recording paper 2 against the heat roller 3 and provides a conveyance force, which rotates in the B direction. 6a and 6b are separation claw units that peel off the recording paper 2 in case it sticks to the roller; 7;
A discharge roller is used to discharge the recording paper 2 in the C direction.

The operation of the fixing device configured as described above will be described below.

The recording paper 2 to which toner has been adhered in the previous process is conveyed to the fixing device. The recording paper 2 is pressed against the heat roller 3 by a backup roller 5. The heat roller 3 melts the toner 1 on the recording paper 2 and fixes it on the recording paper 2. The fixed recording paper 2 is conveyed to a backup roller 5, and is further discharged in the C direction by a discharge roller 7.

In the unlikely event that the recording paper 2 sticks to the heat roller 3 or backup roller 5, the separation claws 6a, 6
A plurality of separation claws provided at b peel off the recording paper 2, and a discharge roller 7 discharges it.

Problems to be Solved by the Invention The above-mentioned fixing device is provided with a separation claw in case the recording paper gets wrapped around the heat roller or back anoflora, and this separation claw is always in contact with the roller. For,
The claws gradually cause scratches on the roller, and toner gets in there and causes image stains, or if the recording paper is not pressed, the roller must be replaced sooner due to these scratches rather than wear. There was a problem.

This was especially noticeable with the backup rollers made of soft silicone rubber.

The above problem arises for the following reasons.

The above-mentioned fixing device uses heat to melt the toner and fix it on the recording paper. When the recording paper wraps around the heat roller and back-up roller, it heats up, emitting smoke or carbonizing, which can lead to a fire. There is a risk of Therefore, a separation claw is provided in contact with the roller in order to prevent this winding.

However, the toner does not melt unless it is in close contact with the heat roller for a certain period of time when it is heated.

Therefore, the heat roller and the backup roller must be in contact with each other with a certain nip width, and therefore, soft silicone rubber is used as a material for the backup roller that comes into contact with the relatively hard heat roller.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a fixing device that is equipped with a separation claw that prevents recording paper from becoming entangled, but in which the separation claw does not damage the backup row 2. do.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention consists of two backup rollers, and the two rollers have separation grooves for separation claws that are offset from each other in the longitudinal direction of the rollers. The separation groove is provided with separation claws that intersect with the outer circumferential circle of the roller.

Function According to the present invention, with the above-described configuration, the tip of the separation claw does not come into contact with the backup roller, so the separation grooves are shifted from each other in the longitudinal direction of the roller without damaging it, so that uneven fixing does not occur.

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

FIG. 1 is a side view showing one embodiment of the present invention, and FIG.
The figure is a perspective view showing the configuration of a backup roller and a separating claw. In these figures, 8 is a guide plate that guides the recording paper, 9 is driven in the E direction by a drive source (not shown), and is a heat source...a heat port containing a rogen lamp (not shown); Reference numeral 10 denotes a separation claw that comes into contact with the heat roller 9, 11 a cleaner that removes toner adhering to the heat roller 9, and 12 a recording sheet to be fixed, which is conveyed in the D direction. Reference numeral 13 designates a backup roller on the document entry side, and is provided with a separation groove 13a. 14 is a bank up roller on the document ejection side, and is provided with a separation groove 14a. 15 is a side plate that fixes the bank up rollers 13 and 14. 16 is Bank Anopuro, 713.
A guide plate 16 that guides the recording paper 12 between 14 and 14 has a convex part, which is a separation piece corresponding to a conventional separation claw, as 16a on the document entry side and as 16b on the document ejection side, which are difficult to separate into separation grooves 13B and 14a, respectively. It is fully equipped.

The operation of the fixing device configured as described above will be described below.

When the recording paper 12 to which the toner is attached in an unfixed state is guided by the guide plate 8 and the backup roller 13, the recording paper 12 is moved to the backup roller 13, which rotates as the heat roller 9 rotates in the E direction. The sheet is further conveyed to the contact portion between the heat roller 9 and the back-up roller 130, where it is heated, pressed, and discharged. The recording paper 12 discharged at this time is transferred to the backup roller 13
Even if the sheet tries to stick to the sheet, it is peeled off by the portion of the convex portion 16a, which is a separation piece, that protrudes from the surface of the backup roller, and is conveyed along the guide plate 16. The recording paper 12 is
It is further conveyed to a backup roller 14, where it is further heated and pressed, and then discharged. Even if the ejected recording paper tries to stick to the heat roller 9, the separation claw 1
0, and even if the backup roller 14 tries to put it on, it will be peeled off at the part of the convex portion 16b, which is a separation piece, that protrudes beyond the surface of the backup roller. In this way, the recording paper 12 is fixed without sticking to the backup rollers 13, 14.

Note that the separation groove 13a and the separation groove 14a are provided at positions shifted from each other in the longitudinal direction of the roller.
The portion not pressed by a is backed up by the backup roller 1.
4, uneven fixing will not occur.

In addition, in this embodiment, the separation claw is the guide plate 1
6, but it need not be taken as part of this and may be provided separately.

Effects of the Invention As is clear from the above description, the present invention comprises two backup rollers, separation grooves are provided in the two backup rollers at positions shifted from each other in the longitudinal direction of the rollers, and the separation grooves are By providing a separation claw for peeling off the recording paper stuck to the backup roller, the separation claw does not come into contact with the bank unroller, so it has the effect of not damaging the backup roller, even though the separation claw is provided. It is something.

[Brief explanation of the drawing]

FIG. 1 is a side view of a fixing device showing an embodiment of the present invention;
FIG. 2 is a perspective view showing the structure of a bank up roller and separation claw showing an embodiment of the present invention, FIG. 3 is a side view showing a conventional fixing device, and FIG. 4 is a perspective view showing a conventional fixing device. FIG. 9... Heat roller, 13. 14...Backup roller, 13a, 14a-separation groove, 15-...
Side plates, 16a, 16b - separation claws. Figure 3

Claims (1)

[Claims] A heat roller equipped with a driving source and having a heating element; a means for separating the heat roller and the recording medium provided on the downstream side in the direction in which the recording medium advances; two backup rollers that abut the heat roller; a plurality of separation grooves provided in each of the two backup rollers at positions shifted from each other in the longitudinal direction of the roller; a separation piece provided in the separation groove and intersecting the outer circumferential circle of the roller on the downstream side in the recording medium traveling direction; A fixing device including a holding member that holds two backup rollers.