JP2001312200A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that failure such as the flocculation and the blocking of recovered toner in a recovered toner container by the influence of heat from a fixing means is caused in an image forming device where the fixing means and the recovered toner container are set to be near, and further temperature irregularity is caused on a heat roller when the inside of the device is cooled by a fan in order to eliminate the failure. SOLUTION: This image forming device is provided with the fixing means, the fan for cooling the inside of a machine, and the recovered toner container. The plural stages of plural ventilating channels communicating with each other are provided between the recovered toner container and the fixing means, and the flow of the air formed by the fan for cooling the inside of the machine is set from the recovered toner container side to the fixing means side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a laser printer, a facsimile, and the like, and more particularly to an apparatus using an electrophotographic image forming technique. The present invention relates to an image forming apparatus having an in-machine cooling fan.

[0002]

2. Description of the Related Art A conventional laser printer using an electrophotographic technique will be described with reference to FIG. In the drawing, each component will be described first.

[0003] The prior art printer comprises a printer body 1,
It is composed of a sheet feeding / conveying unit 2, an image forming unit 3, a laser optical system 4, a fixing unit 5, a discharge tray 61, and the like. As can be seen from this figure, the collected toner container 37 and the fixing unit 5 may be designed very close depending on the layout of the components due to the demand for space saving for saving the installation conditions of the printer.

However, the fixing means 5 and the collected toner container 37
Are close to each other, the toner in the collected toner container 37 is heated to a glass transition temperature (55 to 75 ° C.) by the heat of the fixing unit 5.
And problems such as aggregation and blocking occurred.

In order to solve such a problem, it is conceivable to sufficiently cool the inside of the apparatus by strengthening the cooling fan inside the apparatus. A roller is used, and the temperature of the heat roller on the side of the cooling fan of the heat roller becomes lower than a predetermined temperature, thereby causing temperature unevenness due to cold outside air generated by the cooling fan inside the device.

[0006]

As described above, there is a demand for a technique for lowering the ambient temperature around the fixing means without causing the temperature of the recovered toner container to be easily heated by the fixing means and causing unevenness in the temperature of the heat roller of the fixing means. It is rare.

[0007]

In order to solve the above-mentioned problems, the present invention provides, as a first invention, an image forming apparatus having a fixing means, an internal cooling fan, and a collected toner container. An image forming apparatus, wherein a plurality of air passages are provided between a plurality of fixing means and communicate with each other, and a flow of air generated by the in-machine cooling fan is from a collected toner container side to a fixing means side. Is used.

According to a second aspect of the present invention, the ventilation flow path includes a duct provided between the collected toner container and the fixing means, and a space above the fixing means in a direction crossing the upper surface of the fixing means in a conveying direction. A first space and a second space formed by a shielding plate provided in the fixing device. A vent is provided on an upper surface of the fixing unit facing the second space. The flow of air produced by the fan is determined from the intake port, the duct, the first space, and the second space from the upstream side.
The image forming apparatus according to the first aspect of the present invention uses the space and the exhaust port.

[0009]

By laying out the collected toner container on the upstream side of the flow of air created by the cooling fan in the apparatus and the fixing means on the downstream side, heat from the fixing means is less likely to be transmitted to the collected toner container and further sent to the fixing means. The heated air is heated to some extent in the first space above the fixing means and then sent to the second space for removing the heat of the heat roller, so that the temperature unevenness of the heat roller hardly occurs.

[0010]

FIG. 2 shows an embodiment of a printer adopting the present invention.
It will be described based on. Thick arrow, arrow front symbol,
Although the back symbol of the arrow indicates the flow of the wind, the details of the flow of the wind will be described with reference to another drawing. In the drawing, each component will be described first.

The printer of the present invention comprises a printer main body 1, paper feeding and conveying means 2, an image forming section 3, a laser optical system 4, a fixing means 5, a discharge tray 61 and the like.

The paper feeding and conveying means 2 includes a paper feeding cassette 21,
Paper feed roller 22, transport path (23, 25, 27), registration roller pair (24a, 24b), transport roller pair (26
a, 26b) and a discharge roller pair (28a, 28b). The paper feed cassette 21 can be pulled out to the right side in the drawing, and the transport path 23 is formed by a part of the housing of the cassette and the printer main body. The paper cassette 2
1 has a sheet stacking plate 211 on which a plurality of sheets are stacked, and the sheet stacking plate 211 is moved to the paper feed roller 22 by the top sheet of the sheets stacked by a spring or a lift motor. Energize to touch. The registration roller pair (24a, 24b) stops the sheet once to adjust the timing of transferring the toner image on the photosensitive drum 32 of the image forming unit 3 to the conveyed sheet and to adjust the leading end of the sheet. Has a role of transporting the paper from the printer to the image forming means 3. The transport roller pair (26a, 26
b) The necessary number of the discharge roller pairs (28a, 28b) are laid out in the printer as needed to convey the paper.

The image forming means 3 comprises a unit body 31,
It comprises a photosensitive drum 32, a main charger 33, a developing unit 35, a transfer unit 36, a cleaning unit 37, and a toner cartridge 38. The main charger 33 is 50-1 in a shield case opened toward the photosensitive drum.
A thin tungsten wire of 00 μm is stretched in the longitudinal direction of the photosensitive drum, and the photosensitive drum 32 is positively charged by applying a high voltage of about +5 KV thereto. When the LSU 4 irradiates the charged surface of the photosensitive drum 32 with a laser beam corresponding to image information through the exposure port 34, an electrostatic latent image is formed on the surface of the drum. A laser image is formed by applying the bias voltage of the developing roller and the potential of the surface of the photosensitive drum to the positively charged toner which is agitated in the developing unit 35 on the portion of the photosensitive drum 32 irradiated with the laser, thereby forming a toner image. To the transfer means 36
To the paper conveyed to the nip. In the present embodiment, the transfer unit 36 uses a transfer roller, and a high voltage having a polarity opposite to that of the photosensitive drum 32 is applied.
The untransferred toner on the photosensitive drum is scraped off by the rubber blade 372 of the cleaning means 37 in the next process, and is discharged by a discharge lamp (not shown) in order to make the residual potential on the surface uniform. And then prepare for the next series of processes.

The inside of the cleaning means 37 is a collected toner container 371, and the toner scraped off by the rubber blade is accumulated there.

Particularly, in the image forming section 3, the imaging unit main body 31, the photosensitive drum 32, the main charger 3
3, the developing means 35, the cleaning means 37, and the toner cartridge 38 are unitized, and can be attached to and detached from the printer main body by opening the upper lid 62 and the right lid 63 as shown in FIG. The toner cartridge 38 itself can be replaced when the toner runs out.

The fixing means 5 includes a heat roller 52, a heater 53 therein, a pressure roller 54, and a fixing discharge roller pair (55).
a, 55b) and the like. More specifically, the heat roller 52 is made of a material such as aluminum having good thermal conductivity and coated with fluorine, and has a built-in heater 53 to control the temperature to a predetermined temperature required for fixing. The heat roller 5
The driving of No. 3 may be driven by the contact of the pressure roller 54, but it is preferable that the driving of the roller 3 is driven by the pressure roller 54 by meshing with each other by a helical gear or the like in order to eliminate the fear of slip. The heat roller 52 is opposed to the pressure roller 54 at an appropriate pressure, and is driven by driving means (not shown). The base of the pressure roller 54 is made of an aluminum roller having good heat conductivity, and its periphery is covered with an elastic layer in order to secure a fixing nip width. Although not shown, each roller is provided with a claw member for peeling off the sheet, and a roller or web for cleaning.

These components are unitized and housed in the fixing housing 51, and a shielding plate 561 that partitions a space above the fixing means 5 is provided on the upper portion of the fixing housing 51. In the figure, the right side is the first space 562, and the left side is the second space. Fixing housing 51 and shielding plate 5
Reference numeral 61 is made of a member such as a sheet metal having a large heat capacity. On the upper surface of the fixing housing 51 facing the second space, a plurality of openings 51 for preventing heat from being stored in the fixing means 5.
1 is provided to allow heat to escape therefrom.

The paper discharge tray 61 is provided on the upper part of the printer main body 1 and is also used as an exterior of the printer main body 1.

The operation of the printer will be described with reference to FIG. First, the sheets stacked on the sheet stacking plate 211 are fed one by one to the sheet feeding roller 22 and are fed to the conveyance path 2.
3 and temporarily sent to the registration roller pair (23a, 23a).
At the predetermined timing, the toner is fed to the nip formed by the photosensitive drum 32 and the transfer means 36 of the image forming means 3 and the unfixed toner is transferred to the upper surface of the sheet in the drawing. The sheet having the unfixed toner transferred to the upper surface is sent to the fixing unit 5 via the transport path 25. Here, the toner image is fixed on the paper by being nipped and heated by the nip formed by the heat roller 52 and the pressure roller 54.
Thereafter, the sheet passes through the conveyance path 27 and is discharged from the discharge tray 61.
Is discharged face down.

The structure of the fixing means 5, the collected toner container 371 and its peripheral parts, and the flow of air, which are the characteristic parts of the present invention, will be described with reference to FIGS. FIG. 4 shows the X shown in FIG.
It is sectional drawing of -X.

In FIG. 3, the duct 72 is located between the fixing means 5 and the collected toner container 371, has a ventilation space 722 therein, the intake port 721 opens toward the intake fan 71, and the fixing means side wall 723. A vent 725 is provided at a position opposite to the intake port 721. Since the duct 72 is made of a resin having poor heat conductivity, heat from the fixing unit 5 is not easily transmitted to the collected toner container 371.

Next, the flow of air in the fixing means 5, the collected toner container 371, and the surrounding area will be described in detail with reference to FIG. External air sucked from the intake fan 71 is sent into the duct 72 from the intake port 721 and passes downward through the ventilation space 722 in the figure. At this time, the collected toner container side wall 724 on the side of the collected toner container 371 is cooled by air near room temperature from the outside. This air flows into the first space 562 above the fixing unit 5 through the ventilation port 725, turns back, and flows upward in the drawing. At this time, the outside room temperature air flows while being heated by removing the heat of the upper surface of the fixing means 5 and the shielding plate 561. Subsequently, the first space 5 is formed at a location where the shielding plate
62 and the second space 563 communicate with each other, from which air flows into the second space 563. The air in the second space 563 flows from the upper side in the drawing toward the exhaust port 564 while depriving the heat of the fixing housing 51 and the heat rising from the opening 511,
It is taken out by the exhaust fan 73.

As described above, since the air sent to the fixing means 5 does not directly blow the outside air, the air of the fixing means 5 can be discharged to the outside without the heat roller 52 being excessively cooled.

In this embodiment, two fans, the intake fan 71 and the exhaust fan, are provided, but the same effect can be obtained by providing any one fan. Although the fixing member side wall portion 723 and the collected toner container side wall portion 724 of the duct 72 are made of the same member, the fixing member side wall portion 72 is made of a different material.
3 is made of a material having a large heat capacity and the side wall 7 of the collected toner container.
24 may be used as it is as a member having a heat insulating effect. In addition, although the plurality of openings 511 of the fixing means 5 are uniformly arranged in the same size, the number of openings 511 in the direction in which relatively cool air enters (upward in FIG. 4) is reduced or reduced. By increasing or increasing the number of openings 511 in the exhaust direction (downward in FIG. 4), the unevenness in the temperature of the heat roller 53 can be further improved.

[0025]

According to the present invention, since the heat from the fixing means does not go to the collected toner container, the problem that the collected toner hardens does not occur. Further, since too cold air does not go to the fixing means, temperature unevenness of the heat roller hardly occurs.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a prior art printer.

FIG. 2 is a schematic view of a printer adopting the present invention.

FIG. 3 is a schematic view of the vicinity of a fixing unit and a collected toner container according to the present invention.

FIG. 4 is a cross-sectional view illustrating a flow of air around a fixing unit and a collected toner container according to the present invention.

[Explanation of symbols]

 Reference Signs List 1: printer main body 31; imaging unit 371; collected toner container 5; fixing means 511; opening 561; shielding plate 562; first space 563; second space 564; Inlet 722; vent space 723; fixing means side wall 724; collected toner container side wall 725; vent 73; exhaust fan

Claims (2)

[Claims] An image forming apparatus having a fixing unit, an in-machine cooling fan, and a collected toner container, wherein a plurality of stages of communication with each other are provided between the collected toner container and the fixing unit; The image forming apparatus according to claim 1, wherein the flow of air generated by the cooling fan in the apparatus is from the side of the collected toner container to the side of the fixing unit. 2. A ventilation plate according to claim 1, wherein said ventilation passage is provided with a duct provided between the collected toner container and the fixing means, and a shielding plate provided on a top surface of the fixing means in a direction transverse to the conveying direction. 2 of the first space and the second space formed by
A vent is provided on the upper surface of the fixing means facing the second space, and the flow of air generated by the in-machine cooling fan flows from the intake port, the duct, the first The image forming apparatus according to claim 1, wherein the image forming apparatus includes a space, the second space, and an exhaust port.