JPH0517661U - Fixing unit - Google Patents

Abstract

(57) [Abstract] [Purpose] With respect to the structure of a fixing unit of an electrophotographic recording apparatus, an object thereof is to improve transfer reliability. In a fixing unit in which a sheet on which a toner image on an image carrier is transferred is pressed against a heat roller to be heat-fixed, a heat roller side from a plane connecting a surface of the image carrier and the surface of the heat roller. It is configured to have a protrusion that protrudes to guide the sheet to the heat roller.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the structure of a fixing unit of an electrophotographic recording device. Recently, with the expansion of office automation (OA), plain paper can be used, and output devices with high printing quality have come to be used.

Therefore, a copying machine and a facsimile machine using the electrophotographic recording method have been realized. In these devices, it is important that the toner image transferred onto the paper can be fixed with high quality.

[0003]

[Prior Art]

 As shown in the schematic view of FIG. 2, the electrophotographic recording apparatus to which the present invention is applied includes a photosensitive drum 1 which is an image bearing member having a photosensitive layer on the surface of which the conductivity changes in response to light, and the photosensitive drum 1. Developing device 2 for adhering toner to the drum surface due to the potential difference from the surface of the photosensitive drum 1, charger 3 for uniformly charging the surface of the photosensitive drum 1, and changing the charge amount on the photosensitive drum 1 by scanning the laser beam. An optical system 4 for forming an electrostatic latent image on the photosensitive drum 1, a transfer device 6 for transferring the toner image on the photosensitive drum 1 to the paper 5, and a halogen lamp for heating and fixing the toner image transferred on the paper 5. The fixing unit 7 and the like are provided.

The fixing unit 7 includes a heat roller 8 and a pressure roller 9 for pressing the paper 5 against the heat roller 8 as shown in the side view of FIG. The pressure roller 9 is separable.

That is, the heat roller 8 is rotatably attached to the fixed frame 10 and the pressure roller 9 is rotatably attached to the upper frame 11, and the upper frame 11 is rotatable about the fulcrum 12 in the arrow A direction. .

The sheet 5 to which the toner image on the photosensitive drum 1 has been transferred by the transfer device 6 moves on a plane connecting the surface of the photosensitive drum 1 and the surface of the heat roller 8, and is pressed by the pressure roller 9. Is pressed against the heater 8 and heated by the heat roller 8 to fix the toner image on the sheet 5.

[0007]

[Problems to be solved by the device]

 The sheet on which the toner image has been transferred as described above moves on a plane connecting the surface of the photosensitive drum and the surface of the heat roller, but the movement does not always pass through this surface, and the sheet does not necessarily move. If the tip of the paper hits the pressure roller, the paper will not be fed normally due to the friction with the rubber on the surface of the pressure roller, and the transfer will be disturbed at the transfer part, or the adhesion between the paper and the photosensitive drum will deteriorate and the transfer omission will occur. There was a problem that occurred.

The present invention aims to improve the reliability of transfer.

[0009]

[Means for Solving the Problems]

 In the present invention, as shown in the side view of FIG. 1, the sheet 5 is guided to the heat roller 8 by protruding from the plane connecting the surface of the image carrier 1 and the surface of the heat roller 8 to the heat roller side. The projection 13 is provided.

[0010]

[Action]

 Since the paper that has left the photosensitive drum is pressed by the protrusion and guided in the heat roller direction, it does not contact the pressure roller first.

[0011]

【Example】

 In the present invention, as shown in the side view of FIG. 1, the paper 5 is projected into the heat roller 8 by protruding from the plane connecting the surface of the photosensitive drum 1 and the surface of the heat roller 8 to the heat roller side. The projection 13 is provided.

The protrusion 13 is provided in the paper insertion opening of the upper frame 11 in, for example, an L shape. By doing so, the sheet 5 that has left the photosensitive drum 1 is pressed by the protrusion 13 and guided in the direction of the heat roller 8 as shown in the figure.

For this reason, the sheet 5 does not come into contact with the pressure roller 9 first, and it is possible to prevent the transfer disturbance and the transfer omission as in the prior art.

[0014]

[Effect of the device]

 According to the present invention, the sheet is reliably transferred to the fixing roller, and the transfer disorder and the transfer omission in the transfer section can be prevented, which is a great industrial effect.

[Brief description of drawings]

FIG. 1 is a side view of a fixing unit of the present invention,

FIG. 2 is a schematic view of an electrophotographic recording device to which the present invention is applied,

FIG. 3 is a side view of a conventional fixing unit,

[Explanation of symbols]

 1 image carrier (photosensitive drum), 5 paper, 6 transfer device, 8 heat roller, 9 pressure roller, 10 fixed frame, 11 upper frame, 13 protrusion,

Claims (1)

[Scope of utility model registration request] 1. A sheet on which a toner image on an image carrier (1) is transferred.
In a fixing unit that heat-fixes (5) to a heat roller (8) by pressure, from the plane connecting the surface of the image carrier (1) and the surface of the heat roller (8), A fixing unit comprising a protrusion (13) protruding to the side to guide the sheet (5) to the heat roller (8).