JPH0934323A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device preventing air inside the device containing ozone produced inside the device from being directly discharged to the outside of the device, and preventing toner from sticking to a carrying roller or sheet materials where an image is formed from being stuck each other after the toner is fixed on the sheet material. SOLUTION: This image forming device is provided with an image forming part forming the image on the sheet material, a fixing and paper ejecting part 7 thermally fixing the formed image on the sheet material and ejecting the sheet material to the outside of the device, and a cooling fan 91 (cooling means) blowing off and cooling the image forming surface side of the sheet material carried from the image forming part with the air inside the device at the part 7; and the cooling fan 91 is provided with an ozone filter 92.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an image forming apparatus such as a copying machine or a printer which can form an image on a sheet material by an image forming means such as an electrophotographic system, and discharges the sheet material on which the image is formed. The present invention relates to a device provided with a cooling means for sometimes cooling.

[0002]

2. Description of the Related Art In recent years, as an image forming apparatus, for example, a color image forming apparatus capable of high-speed output of 30 sheets or more per minute has begun to be put into practical use. In such an apparatus, for example, a system of forming a full-color image by superposing toners of four colors of yellow, magenta, cyan, and black and melting and mixing the colors by a heat roller fixing device is adopted. Further, in order to completely mix the four color toners, a large amount of heat is applied in a short time during fixing.

One example is shown in FIG. The apparatus of FIG. 6 is a full-color image forming apparatus, 201 is a main body, and includes the following main components. A reader unit 202 reads a document to be copied. 203a, 203b, 20
Reference numerals 3c and 203d denote image recording units that form yellow, magenta, cyan, and black toner images, respectively.
A transfer unit 204 moves the sheet material to each of the image recording units 203a to 203d and performs a transfer operation.

Further, 205 is a cassette for accommodating the sheet material in the main body, and 206 is a cassette 205 from the transfer unit 20.
4 is a sheet material conveying section for conveying the sheet material. 207
Is a fixing and discharging unit. Reference numeral 208 is a reverse / double-sided conveyance unit, and reference numeral 209 is an intermediate tray for temporarily storing the reversed sheet material.

Reference numeral 210 denotes a paper feeding device externally attached to the main body 201. This paper feeding device 201 is provided with a main body 201 by an engaging means such as a combination of a positioning pin and a hook.
It is positioned and fixed with respect to. Further, reference numeral 301 is an exhaust heat fan for preventing a temperature rise around the fixing device.

The image forming operation of this apparatus is basically as follows.

When the image is read by the reader unit 202, the signal is digitized and sent to the image forming unit 203. Then, the signal is transmitted by the laser beam to the image recording unit 2
A latent image is recorded on the photosensitive drums 03a to 203d and toner is placed by the developing device to form a visible image. The photosensitive drum is charged by a corona charger or the like before being irradiated with laser light.

On the other hand, the sheet material S'is sent from any one of the cassette 205, the sheet feeding device 210, and the manual feed section 212 at the image forming timing of the image recording section, and is visible on the photosensitive drum at the transfer section 204. The image is transferred to the fixing unit 207.
Is heated and fixed.

However, in such an apparatus, the melted toner on the sheet material, which has been heat-fixed, is conveyed by the transport rollers 304, 30 disposed downstream of the fixing section 207.
Since it is not completely solidified by the time it reaches 5, toner may adhere to the rollers while passing through the transport rollers 304 and 305.

Further, in an apparatus capable of high-speed output, even after the sheet material is discharged to the outside of the apparatus, the sheet material accompanied by the fixing toner having a high temperature is stacked on the tray 306 or the like, and is discharged later. There is a phenomenon in which a toner image is attached to the back surface of the sheet material or the sheet materials stick to each other.

For this reason, a method of cooling the sheet material after fixing the sheet material before being nipped and conveyed by the conveying rollers 304 and 305 is adopted. As a configuration for realizing this method, the side wall portion of the main body 201 is provided. There is a fan (not shown) that applies external air to the image forming surface side or the back surface side of the sheet material after fixing, and a device that applies air to the image forming surface side or the back surface side of the sheet material inside the main body 201. there were.

[0012]

However, the conventional image forming apparatus as described above has the following problems.

First, when external air is taken into the main body 201 to cool the sheet material, the temperature of the external air is much lower than the temperature of the sheet material after fixing, so that the sheet material is rapidly cooled. As a result, the curl in the direction of denting the image forming surface of the sheet material, which is generated due to the solidification property of the toner, may be increased, and the sheet material may be clogged at the conveying roller portion and the stackability after discharging may be deteriorated. .

Further, when the air inside the apparatus is applied to the image forming side or the back side of the sheet material, the temperature difference between the sheet material and the air inside the apparatus that hits the sheet material is reduced, and the curl is prevented from increasing. The cooling air inside the apparatus is directly exhausted to the outside of the apparatus from the discharge unit 303 that discharges the sheet material. Therefore, in a device using high-pressure discharge such as a corona charger, ozone generated inside the device is also directly discharged from the inside of the device to the outside.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to prevent the curling of an image-formed sheet material from increasing due to supercooling and to provide an apparatus. This does not directly discharge the air inside the device, which contains ozone generated inside, to the outside of the device.It adheres the toner to the transport roller after fixing the toner on the image-formed sheet material and sticks the sheet materials together. An object of the present invention is to provide an image forming apparatus capable of preventing the above.

[0016]

In order to achieve the above object, according to the present invention, an image forming portion for forming an image on a sheet material and a fixing / discharging device for heating and fixing the formed image to the outside of the apparatus. An image forming apparatus, comprising: a paper unit; and a cooling unit that applies cooling air to the image forming surface side of a sheet material conveyed from the image forming unit in the fixing unit and the paper ejecting unit by applying internal air to the device. The cooling means is equipped with an ozone filter.

Further, an air flow direction plate which guides a part of the internal air of the apparatus conveyed by the cooling means to the fixing / sheet discharging section,
It is also preferable to provide an air flow path for cooling the sheet material before the discharge port for discharging the sheet material to the outside of the apparatus for the internal air guided to the fixing / sheet discharging portion.

Further, the internal air guided to the fixing / sheet discharging portion is blown out of the apparatus through an outlet for discharging the sheet material to the outside of the apparatus to cool the sheet material, and the discharged sheet material is placed. It is also preferable to provide an air flow path that biases the mounting means toward the mounting means.

Therefore, since the internal air of the apparatus is blown to the position where the sheet material is cooled after passing through the ozone filter, the sheet material is cooled at a temperature that does not increase the curl of the sheet material and, at the same time, discharged to the outside of the apparatus. Even if this happens, ozone is prevented from being directly discharged to the outside of the device.

By means of the wind direction plate, the internal air of the apparatus, which has passed through the ozone filter effectively, is supplied to the fixing and discharging section.

Further, the internal air of the apparatus, which has passed through the ozone filter from the outlet for discharging the sheet material to the outside of the apparatus, spreads inside and outside the apparatus and cools the sheet material. Further, since the air blown out of the apparatus is urged toward the placing means for placing the discharged sheet material, it is prevented from descending from above the placing means at the time of discharging the sheet material, and the consistency of the sheet material is improved. good.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The configuration of a first embodiment of an image forming apparatus according to the present invention will be described with reference to FIG.

Reference numeral 1 is a main body, and 2 is a reader unit for reading a document to be copied. 2a is a light source for illuminating an original, 2b
Is a CC that receives the reflected light from the document and converts it into an electrical signal.
D, 2c, and 2d are a mirror unit and a lens unit that guide the reflected light from the document to the CCD. Also, 2e
Is a document table on which a document is set.

Reference numeral 3 designates a cassette portion for accommodating a sheet material, and 3
Reference numeral a is a manual sheet feeding section for manually feeding the sheet material, and reference numeral 4 is a sheet material conveying section for feeding the sheet material from the cassette section to a transfer section described later. Further, 4a is a registration roller for adjusting the sheet feeding timing, and 4b is a sheet feeding roller for feeding the sheet material from the manual feed section 3a.

Reference numeral 40 denotes a sheet feeding device which is detachably attached to the main body 1, and 5a, 5b, 5c and 5d are image recording sections using an electrophotographic system, and subscripts a, b, c and d are. The images correspond to yellow, magenta, cyan, and black images, respectively. Reference numeral 50 denotes a polygon mirror for scanning laser light from a laser light emitting device (not shown), 51a, 51b,
Reference numerals 51c and 51d denote mirror units for guiding laser light from the polygon mirror to a photosensitive drum, which will be described later, and 52a and 52d.
b, 52c and 52d are primary chargers that perform corona discharge,
53a, 53b, 53c, 53d are photosensitive drums, 54
a, 54b, 54c, 54d are developing devices for visualizing the latent image on the photosensitive drum with toner, 55a, 55b, 55c, 5
5d is a cleaner.

Reference numeral 6 denotes a transfer portion, 61 is a transfer belt for adsorbing and conveying a sheet material, 62 is a drive roller for driving the transfer belt 61, 63 is a charger for charging the transfer belt 61, 64a, 64b, 64c, 64d, 65a, 65
Reference characters b, 65c, and 65d are a backup member that transfers the toner image on the photosensitive drum onto a sheet material, and a transfer charger.

Reference numeral 7 denotes a fixing / discharging portion for discharging the toner image after fixing the toner image on the sheet material, and 71 denotes a guide member for guiding the sheet material to a nip portion of a fixing roller pair described later.
72 is an upper roller, and 73 is a lower roller, and the fixing operation is performed in the nip portion where they are in pressure contact with each other. Further, 74a is a post-fixing sensor that detects that the sheet material is discharged from the fixing device 7. 75 is a paper output unit, and 76
Is a pair of paper discharge rollers, 77 is a paper discharge tray, and 78 is a flapper, which switches the destination of the sheet material between the paper discharge direction and the direction of the reversal portion described later. Further, 79 is a curl removing roller for correcting the curl of the sheet material after fixing. Furthermore, 74b
Is a paper discharge sensor that detects that the sheet material has been discharged to the outside of the machine.

Reference numeral 8 is a reversing path, 81a and 81b are conveying roller pairs, and 82 is a reversing roller whose rotation direction is forward / reverse. 81c, 81d, 81e, 81f and 81g are
The conveying roller pair 83 is an intermediate tray for temporarily storing the sheet material on which images are formed only on the front surface during double-sided image formation,
Numerals 84 and 85 are flappers for accommodating each size in the intermediate tray.

Reference numeral 91 is a cooling fan as a cooling means for preventing the fixing / discharging portion 7 from excessively rising in temperature and for cooling the toner surface of the sheet material. Except for a part described later, the cooling fan 91 has front and rear regions separated by an isolation wall such as an inner wall of the device (not shown).

Reference numeral 92 denotes an ozone filter, which dilutes ozone generated from the primary charger 53a, 53b, 53c, 53d for corona discharge when it is discharged to the outside of the apparatus by the cooling fan 91. Furthermore 93 is
This is a wind direction plate for effectively applying a part of the air inside the apparatus conveyed by the cooling fan 91 to the image forming surface (upper surface) of the sheet material to lower the temperature.

Next, a state in which the cooling fan 92 having this structure operates to convey the cooling air to the sheet material will be described with reference to FIG. The cooling air to be blown is indicated by an arrow. Further, components having the same functions as those in FIG. 1 and having the same function are designated by the same reference numerals, and the description regarding these components will be omitted unless particularly necessary.

The cooling fan 91 always operates to prevent excessive temperature rise in the vicinity of the fixing / discharging portion 7 inside the apparatus when the apparatus is operating. As described above, the air inside the apparatus contains a large amount of ozone generated by the primary charger and the like, so that the ozone is removed by passing through the ozone filter 92 and then discharged to the outside of the apparatus. It Further, a part of the wind is regulated in direction by the wind direction plate 93, and is blown in the vicinity of the paper discharge roller pair 76 along the inner wall 94 of the apparatus.

After the sheet material S is fixed by the pair of fixing rollers 72 and 73, the sheet material S passes between the flapper 78 and the guide plate 78a, and is cooled by the wind from above in the vicinity of the pair of discharge rollers 76. However, the guide plate 78a has a shape in which a large number of small holes for passing air are provided, and the cooling air blown through the air flow path for cooling the sheet material before the discharge port through which the sheet material S discharges the sheet material to the outside of the apparatus. It is directly cooled by A1. In addition, a part of the cooling air A2 is blown through the air flow path blown out of the apparatus through the opening 75a of the paper discharge unit, so that the cooling air A2 is generated inside the apparatus.
The sheet material S cooled by 1 can be recooled.

Further, the cooling air A2 blown toward the outside of the apparatus urges the sheet material S in the direction of pressing it onto the sheet discharge tray 77, so that an air layer existing between the sheet material S and the sheet discharge tray 77 causes the sheet material S to press. Since the sheet material S is prevented from swinging back and forth and left and right, the sheet material S during loading is prevented.
It is also possible to improve the consistency of the.

(Second Embodiment) FIG. 3 shows a second embodiment. In this embodiment, the fan 91a and the ozone filter 92a are attached to be inclined in the apparatus. According to this configuration, the loss of the ventilation efficiency of the exhaust portion is minimized, and at the same time, the cooling air regulated by the wind direction plate 93 is effectively conveyed to the fixing / discharging portion 7.

Further, as shown in FIG. 4, by tilting only the ozone filter 92b to form the duct 94 between the cooling fan 91b and the cooling fan 91b, the same action and effect as described above can be obtained.

Further, in order to improve the cooling efficiency upstream of the discharge roller pair 76, as shown in FIG. 5, a comb tooth-shaped guide 78b is provided at a position facing the flapper 78 or upstream of the discharge roller pair 76. By arranging the sheet material S at a predetermined position, the sheet material S is cooled even after the direction of the cooling air A1 hits the sheet material S to become the cooling air A1a.

[0039]

According to the present invention, since the internal air of the apparatus is blown to the position where the sheet material is cooled after passing through the ozone filter, the sheet material is cooled at a temperature that does not increase the curl of the sheet material, and at the same time, Even if it is subsequently discharged to the outside of the device, ozone is prevented from being directly discharged to the outside of the device.

By means of the wind direction plate, the internal air of the apparatus, which has passed through the ozone filter effectively, is supplied to the fixing and discharging section.

Further, the sheet material is cooled from the inside of the apparatus to the outside of the apparatus by blowing the internal air of the apparatus passing through the ozone filter from the outlet for discharging the sheet material to the outside of the apparatus to cool the sheet material. It will be.

Further, since the air blown to the outside of the apparatus is urged toward the placing means for placing the discharged sheet material, it is prevented from falling down from above the placing means at the time of discharging the sheet material, It becomes possible to maintain consistency.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of an image forming apparatus to which the present invention has been applied.

FIG. 2 is a fixing / discharging unit in the image forming apparatus according to the first embodiment.

FIG. 3 is a fixing / ejecting unit in the image forming apparatus according to the second embodiment.

FIG. 4 is a fixing / discharging unit in the image forming apparatus according to the second embodiment.

FIG. 5 is a fixing / discharging unit in the image forming apparatus according to the second embodiment.

FIG. 6 is an image forming apparatus in the related art.

[Explanation of symbols]

 1 main body 2 leader section 3 cassette section 4 sheet material conveying section 4c paper thickness detection sensor 4d environment sensor 5a, 5b, 5c, 5d image forming section 6 transfer section 7 fixing / discharging section 8 reversing path 40 paper feeding apparatus 91 cooling fan ( Cooling means) 92 Ozone filter 93 Wind vane

Claims (3)

[Claims] 1. An image forming unit for forming an image on a sheet material, a fixing / paper discharging unit for heating and fixing the formed image and discharging the image to the outside of the apparatus, and the fixing / paper discharging unit conveying the image from the image forming unit. An image forming apparatus comprising a cooling means for cooling the sheet material by applying internal air to the image forming surface side of the sheet material, wherein the cooling means is provided with an ozone filter. 2. A sheet material is used as a sheet material for a wind vane that guides a part of the internal air of the device conveyed by the cooling means to the fixing / paper discharging unit, and the internal air guided to the fixing / paper discharging unit. The image forming apparatus according to claim 1, further comprising an air flow path that cools the sheet material before a discharge port that discharges the sheet material to the outside. 3. The internal air guided to the fixing / paper discharging unit is blown out of the apparatus from an outlet for discharging the sheet material to the outside of the apparatus to cool the sheet material, and the discharged sheet material is placed. The image forming apparatus according to claim 1 or 2, further comprising an air flow path that urges the mounting means toward the mounting means.