JPH0472228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field) The present invention relates to a recording apparatus having a heat fixing means for fixing an image to a recording material. Typical examples of this device include printing presses, copying machines, facsimile machines, and laser printers.

(Prior art) Generally, heat fixing devices use radiation (non-contact method).
Although heating is also in practical use, roller fixing is mainly used. As this fixing method, the one shown in FIG. 5 is generally used.

Here, explanation will be given using a copying machine as an example. As is generally known, in the copying process system, copy paper on which the original image is visualized by a developer is
The sheet is conveyed to a fixing device by a sheet conveying means disposed within the apparatus, undergoes a fixing process, and is discharged to an output tray outside the apparatus.

The fixing process is shown in FIG.
The pre-fixing guides 10-1, 10-
2 into the fixing device 1. The fixing device 1 is
Consists of a heating roller 2, a pressure roller 3, a cleaning member 4, separation upper and lower claws 7, 6,
The developer material on the unfixed paper is fixed to the paper by heat and pressure, separated from the rollers by separation claws 6 and 7, and after fixing, is passed along guides 111 and 112 by paper discharge rollers 8 and 9. The paper is ejected to a paper output tray, etc. The pressure is applied by fixing inner springs 5, and two are usually used on both sides, one in the front and one in the back.

However, in general, the fixing process for fixing the developed image onto a sheet as a recording material is performed by a fixing device 1 having a combination of a heating roller 2 and a pressure roller 3, as shown in FIG. 5, and the heating temperature is also approximately 200°C.
A very high temperature condition is set up, which is very different from the outside air environment condition. For this reason, if there is a significant temperature difference between the fixing temperature and the outside temperature, dew condensation will occur on parts around the fuser, and especially if dew condensation appears on the conveyance guides before and after the fuser, which is the sheet conveyance means.
The water droplets adhere to the conveyed sheet, making the copy paper wet with water, and in the worst case, the original image on the copy paper blurs and becomes difficult to read. To prevent this, Japanese Patent Application Laid-Open No. 51-68836
As described in Japanese Patent Laid-Open No. 54-96049, it has been proposed to make the guide immediately after the fixing roller smaller to reduce the contact area with the paper and to increase the water vapor diffusion effect. Further, water vapor generated from paper has been diffused between the pair of fixing rollers and the paper ejection roller since before these publications.

On the other hand, in a device that performs double-sided copying or multiple copying as described in Japanese Patent Application Laid-open No. 51-68836, recording materials are transported directly to the outside.
It is provided that this is accomplished by both switching in a given direction (circular path) within the device.

However, in such an apparatus in which the paper after heat-fixing is conveyed in a predetermined direction within the apparatus, the paper must be moved through a long conveyance path after passing through the above-mentioned guide area. As a result, a new problem has arisen in that, although there is sufficient water vapor diffusion in the guide section, water vapor that is partially or locally concentrated in the long conveyance path becomes dew-condensed. Since the water droplets due to dew condensation are non-uniform within the conveyance path, the conveyance resistance varies greatly depending on the area, causing oblique conveyance. This skew is so great that it causes a jam in which the recording material stops in the conveyance path.

In particular, this phenomenon is fatal for multiple recording or double-sided recording, and it is not easy to remove the jam.

In addition, if a long conveyance path is close to an outer wall such as the outer cover of the device, there will be a large amount of dew condensation, and even if the water vapor is diffused by the guide section as proposed above, the conveyance will be affected by the low temperature range from the outer wall. This problem could not be solved because it created a temperature distribution with large variations along the road.

Particularly in continuous multiplex recording and continuous double-sided recording, as the number of sheets increases, the jam occurrence rate also increases, halving the merits of the product.

(Objectives and Summary of the Invention) The present invention aims to solve the above-mentioned objects, and provides a recording device that can significantly reduce the jam occurrence rate and reliably perform multiple recordings on a recording material.

The present invention, which achieves the above object, includes: a heat fixing means for heat fixing an unfixed image on a recording material; a first guide means for ejecting the recording material heat-fixed by the heat fixing means to the outside of the apparatus; In the recording apparatus, the recording apparatus includes a second guide means for conveying the recording material into the apparatus in order to form an unfixed image again on the recording material that has been heat-fixed by the heat-fixing means, and an exterior cover of the apparatus. The second guide means guides the recording material immediately after being heat-fixed by the heat fixing means along the exterior cover which is a side wall of the apparatus, and the second guide means;
The present invention is characterized in that a plurality of openings are provided in the exterior cover that is close to and faces the second guide means.

(Embodiment) In describing the embodiment, please refer to the device described in Japanese Patent Application Laid-open No. 51-68836 for the conventionally known configuration, and only the main parts will be described below.

In the present invention, a plurality of holes are made in the double-sided (multiple) conveyance guide surface immediately after fixing, and a plurality of holes are also made in the exterior cover, so that a state close to the outside air environment is constantly created in the sheet conveyance path inside the device. This prevents condensation and improves reliable paper feeding and copy paper quality.

Immediately after the fixing device 1, a single-sided/double-sided (multiplex) copying mode switching means 17 is provided, and the switching means 17 is switched according to the purpose of the operator, and in the double-sided (multiplex) copying mode, 17 is located at the solid line position in the figure. The sheet is carried into a double-sided conveyance path formed by road walls 112 and 113.

When conveying the recording material to the outside of the apparatus, the switching means 17 is used.
is located below as shown by the broken line, and when the paper is ejected by the guide 111 and the pair of ejection rollers 8 and 9 and conveyed into the inside of the apparatus, the switching means 17 is located above as shown as the solid line. The conveyance path 20 is close to the exterior cover 14, which is a side wall of the apparatus, is a substantially parallel portion, and extends vertically downward, guiding the recording material to a predetermined portion (not shown).

The conveyance path 20 has cutout openings b and c as a plurality of openings having a characteristic configuration of the present invention.
This allows air to flow into the interior. The water vapor generated in the transport path 20 is diffused by the openings b and c, and at the same time, the recording material is air-cooled, so that the generation of water vapor is suppressed. As a result, the area in which the openings b and c are provided can be made small, and the heat dissipation area of the recording material can also be made small.

In the present invention, in order to enhance this effect, the conveyance path 2
The cover 14 facing 0 is also provided with a plurality of openings e, and in this example, the opening e is smaller than the openings b and c. This opening e allows the atmosphere outside the apparatus to easily and quickly flow into the conveyance path 20.

Further, in this embodiment, an opening a is formed in the transport guide 111 and a part of the corresponding road wall 113 (which may be considered as one end of the transport guide pair), and an opening a is formed in the cover 13 located above the transport guide 111. opening d
There are several of each. This allows the air inside the device and the outside air to flow freely into or out of the device through these notches, removing hot air from the fuser and moist air from evaporated oil and moisture during fusing. Air flows out. Therefore, the temperature difference between the outside temperature and the temperature around the fixing device is alleviated, and dew condensation on the guide plate surface can be prevented.
Furthermore, the presence of notches in the guide plate itself reduces the area on which water droplets adhere, significantly reducing water droplets compared to a guide plate without notches. In addition, as is clear from FIG. 2, the notch openings a, b, and c of the embodiment of the present invention are in the shape of round elongated holes centered on the axis tilted by ±0 with respect to the direction of the arrow in the paper advancing direction. The center where the plus and minus signs change is located approximately at the center of the paper width. Further, the value of θ can be any value between 0° and 30°. However, the closer the angle is to 0°, the further away from the edge of the paper the notch should be. In addition, the shape of the notch can be a variety of shapes such as a round hole, a triangle, a base shape, and a teardrop shape (Fig. 4 a, b, c), which prevents paper from sticking into the notch. If the diaphragm shape is made perfect (e in the A-A cross section in Figure 4 d and d), paper feeding reliability can be further improved. Regarding the notches d and e of the exterior cover, the shape should be determined from a design point of view, and there is no one that is better than the other.

Further, as a means of ventilation near the guide plate, a fan or the like may be used forcibly. Furthermore, the same effect as described above can be obtained by using a guide plate shaped like a net or made of wire.

Furthermore, although an example has been given in which the conveyance path is formed by the two road walls 112 and 113, the conveyance path may be formed by the exterior cover 14 and one of the road walls 112 and 113.
It may be formed with a rib guide (or a rib guide with a notch opening f) as shown in the side and perspective views of FIGS. 6 and 7. Furthermore, it is preferable that the rib guide 141 is integrated with the exterior cover (it is even better if it has a notch opening g), since the strength is improved and the air flow becomes more reliable.

From what has been described above, the sheet conveyance means seen in the embodiments of the present invention prevents dew condensation, reduces the contact resistance between the sheet conveyance guide and the paper (the contact area with the paper is also reduced by the cutouts), and achieves high reliability. A certain paper feeding means can be provided.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are explanatory diagrams of embodiments of the present invention, respectively.
FIG. 3 is a layout diagram of the guide plate notches of the present invention, FIGS. 4 a, b, c, d, and e are explanatory diagrams of other notch shapes, and FIG. 5 is a schematic diagram of the vicinity of the fixing device of the conventional example. 6th
7 are a sectional view and a perspective view of another embodiment, respectively. 1 is a fixing device, 2 is a heating roller, 3 is a pressure roller, 13 and 14 are exterior covers, 20 is a conveyance path, 1
12, 113 are road walls, a, b, c, d, e, f,
g is the notch opening.

Claims (1)

[Scope of Claims] 1. A heat fixing means for heat fixing an unfixed image on a recording material, a first guide means for discharging the recording material heat-fixed by the heat fixing means to the outside of the apparatus, and a heat fixing means. A recording device comprising: a second guide means for conveying a recording material into the device in order to form an unfixed image again on the recording material that has been heat-fixed by the device; and an exterior cover of the device; The guide means guides the recording material immediately after heat fixing by the heat fixing means along the exterior cover which is a side wall of the apparatus, and the second guide means and the second
A recording device characterized in that a plurality of openings are provided in an exterior cover that faces the guide means in close proximity.