JPH06118818A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the sticking of toner and paper powder to a guiding means and the occurrence of jamming by forming a layer having releasability on the guiding surface of the guiding means guiding a transfer material finished to pass a fixing means. CONSTITUTION:When a toner image T on the transfer material P is completed to pass a nip part formed by a fixing roller 31 and a pressure roller 33, the toner image T is heated, melted and fixed on the transfer material P. For the transfer material P finished to pass the nip part, a carrying path is determined by elected paper upper and lower guides 38 and 39. Ribs 38a and 39a are provided on the elected paper guides 38 and 39, respectively and the ejected paper guides 38 and 39 come into contact with the transfer material through the ribs 38a and 39a. Then, Teflon films 42 are stuck to the elected paper upper and lower guides 38 and 39 and the ribs 38a and 39a, respectively. At this time, the Teflon film has high releasability so that even if the transfer material P is abutted on the ribs 38a and 39a, the toner and paper powder hardly stick to the ribs 38a and 39a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having fixing means for heating and fixing an unfixed image on a transfer material.

[0002]

2. Description of the Related Art In image forming apparatuses such as copying machines and printers, a heat roller fixing method is widely used as a method for fixing a toner image on a recording material.

Further, recently, a film fixing system using a thermal head and a thin film has been proposed for the purpose of reducing the warm-up time (Japanese Patent Laid-Open No. 63-3131).
82, JP-A-2-157878).

In all of these methods, heat is used to melt the toner and fix the toner to the transfer material.
This heat may cause the transfer material to curl or generate wrinkles. It is also necessary that the transfer material be easily separated from the fixing roller, the film, the pressure roller and the like. Therefore, generally, a discharge guide is provided as a guide for the transfer material, following the heating unit.

[0005]

However, the above-mentioned conventional example has the following drawbacks. That is, the molten toner on the transfer material is not yet sufficiently cooled immediately after heating. Therefore, if the molten toner on the transfer material comes into contact with the discharge guide (paper discharge upper guide) at this point, the toner adheres to the discharge paper upper guide, and when the transfer material is conveyed. There was a problem that the adhered substances (paper powder, toner) were caught.

Therefore, a method has been devised in which ribs are set up on the paper discharge guide and only the ribs contact the transfer material. In this method, dust such as paper dust and toner is generally piled up and attached between the ribs of the discharge guide, so that the phenomenon of being caught during transfer material transfer is reduced. However, this time, paper powder and toner adhered to the ribs, causing problems such as scratches on the transfer material and catching of the transfer material.

[0007]

The present invention prevents toner and paper dust from adhering to the guide means for guiding the transfer material that has passed through the fixing means, and the transfer material is scratched by the paper dust and toner. The purpose is to prevent jamming.

The constitution of the present invention for achieving the above-mentioned object is to form a toner image on a transfer material, and to heat the transfer material on which an unfixed toner image is formed by the image forming means to heat the toner. An image formation characterized by having a fixing means for fixing an image and a guide means for guiding the transfer material that has passed through the fixing means, and forming a layer having releasability on the guide surface of the guide means. It is a device.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an image forming apparatus using a fixing device according to an embodiment of the present invention.

Reference numeral 1 denotes an original placing table made of a transparent member such as glass, which reciprocates in the direction of arrow a to scan the original. A short-focus small-diameter image-forming element array 2 is arranged immediately below the original document table 1, and an original image placed on the original document table 1 is illuminated by an illumination lamp 3, and a reflected light image thereof is formed by the array 2. Slit exposure is performed on the photosensitive drum 4. The photosensitive drum 4 rotates in the direction of arrow b. Further, 5 is a charger, for example, uniformly charging the photosensitive drum 4 coated with a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. On the photosensitive drum 4 uniformly charged by the charger 5, an electrostatic image formed by image exposure by the array 2 is formed. This electrostatic image (electrostatic latent image) is visualized by the developing device 6 using powder toner made of resin or the like that is softened and melted by heating. On the other hand, a transfer material P such as a recording paper stored in the cassette S is rotated in a vertically pressed state at a timing so as to be synchronized with the image on the feeding roller 7 and the photosensitive drum 4. It is sent onto the photosensitive drum 4 by the carrying roller 8. Then, the transfer discharger 9 transfers the toner image formed on the photosensitive drum 4 onto the recording material P. After that, the transfer material P separated from the photosensitive drum 4 by the known separation means is guided to the fixing device 11 by the conveyance guide 10, is heated and fixed, and is then discharged onto the tray 22. After the toner image T is transferred, the residual toner on the photosensitive drum 4 is removed by the cleaner 23.

FIG. 2 is a sectional view of the scanning apparatus according to the embodiment of the present invention. That is, the fixing roller 31 that has been heated by the fixing heater 32 and the pressure roller 33 rotate in the direction of the arrow, and heat and press the transfer material P to sandwich and convey it. The fixing roller 31 is controlled to a predetermined temperature by the temperature detecting element 20. As cleaning of the fixing roller 31,
A cleaning member 30 is arranged. The toner image T on the transfer material P is heated and melted when passing through the nip portion formed by the fixing roller 31 and the pressure roller 33,
The transfer material P is fixed.

The transfer material P that has passed through the nip portion has a conveyance path determined by an upper discharge guide 38 and a lower discharge guide 39. The paper discharge vertical guide also has an effect of preventing wrinkles and curls of the transfer material P. The paper is ejected by the paper ejection upper roller 36 and the paper ejection lower roller 37. The drive of the paper discharge roller is taken from gears 40 and 41 (FIG. 3,
(Fig. 4).

Ribs 38a and 39a are provided on the paper discharge guides 38 and 39, respectively, and the paper discharge guides come in contact with the transfer material P by the ribs. Originally, the same effect can be obtained even if the ribs are not provided, but when the ribs are present, the transfer material P is unlikely to be caught because the transfer material P is easily dropped between the ribs even if an adhered matter or the like is generated.

In this embodiment, a Teflon film 42 (PFA = polytetrafluoroethylene perfluoroalkyl ether copolymer) is attached to the upper discharge guide 38, the lower discharge guide 39 and the respective ribs 38a, 39a.

Due to the high releasability of the Teflon film 42, even if the transfer material P comes into contact with the ribs 38a and 39a, it is difficult for toner and paper dust to adhere to the ribs 38a and 39a, so that the image portion of the transfer material P is made. No scratches or scratches due to deposits during transportation.

It should be noted that the discharge guides 38 (ribs 38a) and 39 (ribs 39a) are both necessarily the release layer 42.
It is not necessary to provide, and the effect can be seen only on one side. For example, this embodiment is applied to the paper discharge upper guide 38 because the distance between the paper discharge and the heating nip is short, or the time when the transfer material passes is short, that is, the transfer material is guided to the paper discharge upper guide 38 before the toner T is sufficiently cooled. It was effective when P abuts. Further, it is particularly effective to apply this embodiment to the paper discharge lower guide 39 when many double-sided copies are made or a large amount of paper dusty paper is taken.

(Other Embodiment) FIGS. 5 to 9 show another embodiment of the present invention.

FIG. 5 shows a case where a Teflon tape 43 is used as a release layer instead of the Teflon film.

FIG. 6 shows a case where a release layer 44 is coated instead of the film or tape. That is, this is a case where heat-resistant polyimide is used for the paper ejection guides 38 and 39 and Teflon coating is performed. In this case, as Teflon, PTF
Coated with E (tetrafluoroethylene), PFA, FEP (tetrafluoroethylene-hexafluoropropylene copolymer) and the like. In addition to the above, when the paper discharge guides 38 and 39 are made of normal heat-resistant resin, epoxy-modified acrylic resin mixed with Teflon particles is applied, and then UV-cured to provide a release layer (UV The effect was recognized even with a coat). In this case, it is easy to carry out because the base resin has a normal heat resistance.

Further, in the release layer of the coat or film, resistance may be lowered, for example, carbon or the like may be dispersed in order to prevent electrostatic charging.

FIG. 7 shows still another embodiment. That is, this is a case where the release layer 42 Teflon film is provided only in the portion (rib portion 38a) in contact with the transfer material.

FIG. 8 shows another embodiment, in which the rib portion 3
This is the case where 8a is made of a different material and is later bonded to the paper ejection guide 38. . This is particularly easy to implement because the Teflon coat 44 requires high heat resistance only in the rib portion 38a.

FIG. 9 shows a case where the above-mentioned respective embodiments are applied to the film fixing method instead of the heat roller method. That is, a film 50, a driving roller 51, and a film guide plate 52 are provided instead of the fixing roller, a heater 53, a holder 54, and a stay 55 are provided instead of the heater 32, and a thermistor 56 is arranged. In each case, the desired effect was obtained.

The releasable layer may be formed by coating the guide with a releasable film.

[0026]

As described above, by providing a layer having excellent releasability on the rib surface of the discharge guide, toner and paper dust adhere to the rib portion of the discharge guide that contacts the transfer material. This has the effect of preventing this, and preventing the transfer material from being rubbed or caught during transportation.

[Brief description of drawings]

FIG. 1 is a sectional view of an image forming apparatus embodying the present invention.

FIG. 2 is a sectional view of an essential part of an image forming apparatus embodying the present invention.

FIG. 3 is a cross-sectional view of the guide means of the image forming apparatus embodying the present invention, cut away.

FIG. 4 is a cross-sectional view of the guide means of the image forming apparatus embodying the present invention, cut away.

FIG. 5 is a sectional view of another embodiment of the present invention.

FIG. 6 is a sectional view of another embodiment of the present invention.

FIG. 7 is a sectional view of another embodiment of the present invention.

FIG. 8 is a sectional view of another embodiment of the present invention.

FIG. 9 is a sectional view of another embodiment of the present invention.

[Explanation of symbols]

 31 Fixing Roller 32 Heater 33 Pressure Roller 34 Inlet Lower Guide 35 Inlet Upper Guide 36 Ejecting Upper Roller 37 Ejecting Lower Roller 38 Ejecting Upper Guide 39 Ejecting Lower Guide 40 Ejecting Upper Roller Driving Gear 41 Ejecting Lower Roller Driving Gear 42 Separation Mold layer (Teflon film) 43 Release layer (Teflon tape) 44 Release layer (Coat layer) 38a Paper ejection upper guide rib 39 Paper ejection lower guide rib 50 Fixing film 51 Drive roller 52 Film guide plate 53 Heater 54 Heater holder 55 Heater stay 56 Thermistor P Transfer material T Toner

Claims (6)

[Claims] 1. An image forming means for forming a toner image on a transfer material; a fixing means for heating the transfer material on which an unfixed toner image is formed by the image forming means to fix the toner image; An image forming apparatus comprising: a guide unit that guides the transfer material that has passed through the unit; and a layer having releasability formed on the guide surface of the guide unit. 2. The image forming apparatus according to claim 1, wherein the releasable layer is formed by attaching a film made of a releasable material to the guide surface. . 3. The image forming apparatus according to claim 1, wherein the releasable layer is formed by applying a tape made of a releasable material to the guide surface. . 4. The image forming apparatus according to claim 1, wherein the layer having releasability is formed by coating the guide surface with a material having releasability. 5. The image forming apparatus according to claim 1, wherein the guide unit has a plurality of ribs, and the guide surface is formed on the ribs. 6. The image forming apparatus according to claim 1, wherein the layer having releasability is a coating of a film having releasability on the guide surface.