JPH07261585A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the waterdrops on a paper discharge guide from sticking to the paper regardless of the dew condensation on the paper discharge guide due to the moisture generated from the paper, prevent a paper jam and the irregular alignment and a stain of the paper, and improve reliability by holding a space section, and covering the slide section of a guiding means with the paper. CONSTITUTION:A paper discharge guide 37 made of a plate metal and serving as a guiding means supporting and guiding the paper P is provided between a fixing roller 33 and a paper discharge roller 34. A guide cover 38 made of Mylar, rising from the side face of the fixing roller 33 side, and serving as a covering means covering a guide face 37a is provided on the flat guide face 37a serving as a slide section of the paper discharge guide 37 with the paper P. The guide cover 38 is mounted on the guide face 37a via a rib 38a, and a space section 40 is provided between the guide face 37a and guide cover 38. The temperature of the guide face 37a is not transmitted directly to the guide cover 38, and no waterdrop is stuck to the guide cover 38 even when the ambient temperature is low.

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 such as an electrophotographic apparatus which performs fixing by a pair of fixing rollers having a heating roller.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a copying machine, a paper discharge guide including a sheet metal part for guiding the paper to the paper discharge roller is provided in a paper conveyance path from a fixing roller to a paper discharge section. There is.

On the other hand, in the fixing roller, the moisture contained in the paper evaporates at the time of heat fixing, but the environment temperature is low such as in cold regions and early morning in winter, and the devices around the fixing roller are cold. Then, the evaporated water was condensed as dew on peripheral devices such as a paper ejection guide to generate water droplets.

[0004]

Conventionally, the sheet is guided and supported from the fixing roller to the sheet discharge section by the sheet discharge guide composed of sheet metal parts. Therefore, in a low-temperature environment, the moisture contained in the paper evaporates at the time of heat fixing.However, when water droplets condense on the cooled paper ejection guide and become condensed, and these water droplets adhere to the paper passing through the paper ejection guide, There are problems such as paper jams and uneven discharge of paper, and the paper becomes dirty and wavy.

Therefore, the present invention eliminates the above-mentioned problems, and when the paper is supported and guided by the paper ejection guide regardless of the condensation of water generated from the paper on the paper ejection guide,
An object of the present invention is to provide a highly reliable image forming apparatus that prevents water droplets on the paper discharge guide from adhering to paper and does not cause paper jams, paper irregularities, and paper stains.

[0006]

In order to solve the above problems, the present invention provides an image forming means for forming a developer image on a sheet in a main body of an apparatus, and an image forming means for forming a developer image on the sheet while sandwiching and conveying the sheet. Fixing means for heating and fixing the developer image, discharging means for discharging the sheet fixed by the fixing means to the discharging section of the apparatus main body, and supporting and guiding the sheet after the heat fixing in the discharging means direction. A flat plate-shaped guide means and a covering means for covering the sliding contact portion of the guide means with the sheet while holding the space portion are provided.

In order to solve the above-mentioned problems, the present invention further comprises an image forming means for forming a developer image on a sheet in the main body of the apparatus, and heating the developer image on the sheet while sandwiching and conveying the sheet. A fixing means for fixing, a discharging means for discharging the sheet fixed by the fixing means to a discharging section of the apparatus main body, and a sheet metal part having a flat plate shape for supporting the sheet after the heat fixing in the discharging means direction. Guidance means to guide,
Covering means, which is made of a material having a lower thermal conductivity than that of the guiding means, is provided to cover the sliding contact portion of the guiding means with the sheet while holding the space portion.

Further, in order to solve the above problems, the present invention provides
An image forming unit that forms a developer image on a sheet in the main body of the apparatus, a fixing unit that heats and fixes the developer image on the sheet while nipping and conveying the sheet, and the sheet fixed by the fixing unit. Discharging means for discharging the sheet to the discharging section of the apparatus main body, and guide means for supporting and guiding the sheet after completion of heat fixing in the discharging means direction, which is composed of a flat plate-shaped metal plate part
Covering means, which is made of a material having excellent heat resistance and a lower thermal conductivity than that of the guide means, is attached to a sliding contact portion of the guide means with the sheet via a rib.

[0009]

According to the present invention, by the above-mentioned means, the covering means covers the sliding contact portion of the guide means with the paper, and the space portion is held between the covering means and the guide means, and the paper is supported and guided by the covering means. As a result, even if water droplets adhere to the guide means, the water droplet adhered portion is covered by the covering means, so that it is possible to prevent the water droplets from adhering to the paper. This prevents paper jams due to water wetting of the paper, unevenness of the paper at the time of paper discharge, and prevention of stains such as dirt and undulation on the paper.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic explanatory view of an image forming apparatus. An image forming unit 2 for performing charging, exposure, development, transfer, peeling, cleaning, charge removal, fixing, etc. is built in the apparatus main body 1, and the apparatus main body 1 includes A document table 3 that supports the document D is provided on the upper surface. Reference numeral 4 denotes a document table cover that covers the document table 3.

A front loading type sheet feeding cassette device 10 for accommodating sheets to be supplied to the image forming means 2 is detachably attached to the lower part of the apparatus main body 1, and on the right side of the apparatus main body 1. A paper feed tray 11 for manually feeding the paper P is provided. 30a, 30b
Are first and second pick-up rollers for taking out the paper P from the paper feed cassette device 10 or the paper feed tray 11.

The image forming means 2 has the following structure. That is, the photoconductor drum 20 is arranged substantially in the center of the apparatus main body 1, and around the photoconductor drum 20,
The charging charger 21, the exposure unit 22a of the exposure device 22, the developing device 23, the transfer charger 25, the peeling charger 26, and the cleaning device 2 which are well known in the related art along the rotation direction thereof.
7 and the static eliminator 28 are sequentially arranged.

Further, the photosensitive drum 20 in the apparatus main body 1
On the upstream side, a first sheet-feeding cassette device 10 or a sheet-feeding tray 11 is provided to prevent the double picking of the sheets P from being fed.
Further, the second separation / conveyance rollers 31a and 31b, the guide roller 35, and the registration roller 32 that conveys the sheet while aligning the leading ends of the sheet P and synchronizing the developer image formed on the photosensitive drum 20 are arranged. On the downstream side, a conveyor belt 36, a pair of fixing rollers 33 as fixing means, and a discharge roller 34 as discharge means for discharging the paper P from the fixing roller 33 to the discharge tray 12 as discharge section are arranged. There is.

The fixing roller 33 has a heater 33a.
And a pressure roller 33c that is pressed against the heat roller 33b by a pressure spring (not shown). The heating roller 33b is rotated by a drive motor (not shown), and the pressure roller 33c is rotated.
Is pressed against this and is driven to rotate. 5 more
Reference numeral 3 denotes a peeling claw, and 54 is a cleaner for slidingly contacting the heating roller 33b.
This is a cleaning device having a Ning felt 54a.

From the fixing roller 33 to the paper discharge roller 34
During the period of reaching, the paper discharge guide 37 which is a guide means for supporting and guiding the paper P and is made of a sheet metal is provided. A flat guide surface 37 that is a sliding contact portion of the paper ejection guide 37 with the paper.
A guide cover 38, which is made of mylar, is a covering means that rises from the side surface on the fixing roller 33 side and covers the guide surface 37a. This guide cover 3
8 is placed on the guide surface 37a via the rib 38a, whereby a space portion 40 is interposed between the guide surface 37a and the guide cover 38.

Next, the copy operation of the apparatus main body 1 will be described. When the power source (not shown) is turned on, the heater 33a in the apparatus main body 1 is turned on and the fixing roller 33 starts warming up. After the warm-up is completed, after the apparatus main body 1 is in the ready state, the document D is set on the document table 3 and the copy conditions such as the number of copies and the paper size are set by a numeric keypad or the like on the operation panel (not shown). Then, a copy key (not shown) is turned on to start the copy operation. By the start of this copying operation, the photosensitive drum 20 is sequentially subjected to the steps of charging, exposure and development by the image forming means 2 in accordance with the rotation thereof to form a developer image.

On the other hand, in the paper feed cassette device 10 or the paper feed tray 11, the paper P taken out by any one of the pickup rollers 30a, 30b is separated one by one by the separating / conveying means 31a, 31b, and is registred. To the transfer charger 25 of the photoconductor drum 20 in synchronism with the developer image on the photoconductor drum 20 by the image forming means 2 and the developer on the photoconductor drum 20. The image is transferred.

Further, the sheet on which the developer image is transferred is peeled from the photosensitive drum 20 by the peeling charger 26, and is conveyed to the fixing roller 33 by the conveying belt 36 and inserted between the heating roller 33b and the pressure roller 33c. Then, the image is heated and pressure-fixed, and is discharged toward the paper discharge tray 12.
On the other hand, after the transfer is completed, the photosensitive drum 20 follows the rotation thereof,
The cleaning device 27 removes the residual toner, and the static eliminator 2
The electricity is removed at 8 and the next copy is made possible. Then, the above copy operation is repeated to obtain the required number of copies.

During this time, the fixing roller 33 repeats the heating and fixing of the toner image on the paper P, but at the time of fixing, the water contained in the paper P evaporates from the heated paper P. When the environment temperature around the fixing roller 33 is low, such as in a cold region or early morning in winter, and the discharge guide 37 is still cold immediately after the power is turned on, the fixing roller 33 is fixed.
The water evaporated from the paper is cooled by the paper discharge guide 37 and adheres as water drops. The number of places where the water drops are generated is particularly large on the side close to the fixing roller 33.

However, regardless of the dew condensation on the paper ejection guide 37, the guide surface 37a of the paper ejection guide 37 is covered with a guide cover 38 made of Myra having a low thermal conductivity, and the guide surface 37a and the guide cover 38 are formed. Since the space 40 is provided between the guide cover 38 and the temperature of the guide surface 37a is not directly transmitted to the guide cover 38, water droplets do not adhere to the guide cover 38 even if the environmental temperature is low, and the space under the The layer 40 is in a state where water droplets attached to the paper ejection guide 37 are accumulated.

Therefore, after the fixing is completed, the sheet P separated from the fixing roller 33 reaches the sheet discharge roller 34 by being guided and guided on the guide cover 38 having no water droplets attached thereto.
The sheet is discharged onto the sheet discharge tray 12, and the copy operation is completed.

After that, copying is performed in the same manner, but during that time, when the temperature of the peripheral device is raised by the heat generated from the heating roller 33b, regardless of the generation of water from the paper P during fixing, No water droplets adhere to the paper ejection guide 37, and the water droplets adhered to the transport guide immediately after the power is turned on are also evaporated.

According to this structure, the water evaporated from the sheet at the time of fixing is attached to the discharge guide 37 as water droplets, but the guide surface 37a with which the sheet P is slidably contacted does not have the droplets attached thereto. 38, the paper P is supported and guided on the guide cover 38. Therefore, unlike in the conventional case, water drops will not adhere to the back surface of the paper P, which will not cause paper jams due to poor conveyance and unevenness during paper discharge. Also, stains and distortion of the paper P due to water wetting can be prevented and ensured. The paper P can be conveyed, and the reliability of the device can be improved.
Incidentally, the present invention is not limited to the above-mentioned embodiment, and can be modified within a range that does not change the gist of the invention. In addition to having a low conductivity, it has a small friction coefficient in order to smoothly convey the paper P, and further, since it is heated to a high temperature by the fixing means, it may have excellent heat resistance. . Further, the shapes of the guide means and the covering means, the space between the both means, and the like are arbitrary as long as they do not impair the transportability of the sheet, and in the embodiment, the height of the rib 38a is adjusted. It is also possible to adjust the thickness of the space.

[0024]

As described above, according to the present invention, even if the water generated during fixing adheres to the guide means as water droplets, the sheet does not directly touch the guide means after the fixing is completed. The back surface is supported by the covering means and is guided toward the discharge portion. Therefore, water droplets that have condensed on the guide means will not be attached to the paper, and it is possible to reliably prevent paper jams and paper misalignment that occur due to poor conveyance caused by water wetting of the paper, and reliability of the device. Is improved,
It also prevents the paper from being soiled due to water getting wet.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a device body of an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a conveyance guide and a guide cover according to an embodiment of the present invention.

FIG. 3 is a side view showing a conveyance guide and a guide cover according to an embodiment of the present invention as seen from the arrow B side in FIG.

FIG. 4 is a side view showing a conveyance guide and a guide cover according to an embodiment of the present invention as viewed from the arrow C side in FIG.

[Explanation of symbols]

 1 ... Device body 33 ... Fixing roller 37 ... Paper ejection guide 38 ... Guide cover 40 ... Space section

Claims (3)

[Claims] 1. An image forming unit for forming a developer image on a sheet in a main body of the apparatus, a fixing unit for heating and fixing the developer image on the sheet while nipping and conveying the sheet, and a fixing unit. Discharge means for discharging the fixed paper to the discharge portion of the apparatus main body, flat guide means for supporting and guiding the paper after the heat fixing in the discharge means direction, and the paper of the guide means. An image forming apparatus comprising: a covering unit that covers the sliding contact portion while holding the space portion. 2. An image forming means for forming a developer image on a sheet in a main body of the apparatus, a fixing means for heating and fixing the developer image on the sheet while nipping and transporting the sheet, and a fixing means. Discharging means for discharging the fixed sheet to the discharging section of the apparatus main body, guide means for supporting and guiding the sheet in the discharging means direction after completion of heating and fixing, which is composed of a flat sheet metal part. An image forming apparatus comprising: a covering member made of a material having a lower thermal conductivity than the guide member and covering a sliding contact portion of the guide member with the sheet while holding a space. 3. An image forming means for forming a developer image on a sheet in a main body of the apparatus, a fixing means for heating and fixing the developer image on the sheet while nipping and conveying the sheet, and a fixing means. Ejection means for ejecting the fixed paper to the ejection part of the apparatus main body, guide means for supporting and guiding the paper after the heat fixing in the ejection means direction, which is composed of a flat sheet metal part, and has excellent heat resistance. An image forming apparatus comprising: a covering member which is made of a material having a lower thermal conductivity than that of the guiding member and which is attached to a sliding contact portion of the guiding member with the sheet via a rib.