JP3556152B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL 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, in which a collected toner container is laid out near a fixing unit, and an image having a cooling fan inside the machine. The present invention relates to a forming apparatus.
[0002]
[Prior art]
A laser printer using a conventional electrophotographic technique will be described with reference to FIG. In the drawing, each component will be described first.
[0003]
The conventional printer includes a printer main body 1, a sheet feeding and 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 means 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.
[0004]
However, when the fixing unit 5 and the collected toner container 37 are close to each other, the toner in the collected toner container 37 exceeds the glass transition temperature (55 to 75 ° C.) due to the heat of the fixing unit 5, causing problems such as aggregation and blocking. Had occurred.
[0005]
In order to solve such problems, it is conceivable to cool the inside of the machine sufficiently by strengthening the cooling fan inside the machine.However, fixing means such as small printers use small heat rollers with small heat capacity so that printing can be started immediately. Accordingly, temperature unevenness occurs such that the temperature of the heat roller on the side of the cooling fan inside the machine becomes equal to or lower than a predetermined temperature due to the cold outside air generated by the cooling fan inside the machine.
[0006]
[Problems to be solved by the invention]
As described above, there is a demand for a technique in which the recovered toner container is hardly heated by the fixing unit and the ambient temperature around the fixing unit is reduced without causing temperature unevenness in the heat roller of the fixing unit.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides, as a first invention , a fixing unit, a collected toner container, a duct laid out between the fixing unit and the collected toner container, and a flow of air to the duct. An image forming apparatus having an in-machine cooling fan for forming an image, wherein an inlet is provided on one side of the duct, and a vent is provided on a wall on the opposite side of the fixing means, and an image which has entered through the inlet is provided. Air outside the forming apparatus moves in the duct, flows into the upper part of the fixing unit through a vent provided on the wall of the fixing unit on the side opposite to the intake port, and generates heat from the fixing housing and the fixing unit. An image forming apparatus characterized in that heat rising from an opening formed in a housing is discharged to the outside of the image forming apparatus.
[0008]
According to a second aspect of the present invention, the wall of the duct on the fixing means side is made of a material having good heat conductivity , and the side wall surface of the collection container of the duct is made of a material having poor heat conductivity. An image forming apparatus according to claim 1 is used.
[0009]
[Action]
By laying out the recovered toner container on the upstream side of the air flow created by the internal cooling fan and the fixing unit on the downstream side, heat from the fixing unit is less likely to be transmitted to the collected toner container, and the air sent to the fixing unit is Since the duct is heated to some extent, the heat roller hardly generates temperature unevenness.
[0010]
【Example】
An embodiment of a printer adopting the present invention will be described with reference to FIG. In the drawing, each component will be described first.
[0011]
The printer according to the present embodiment includes a printer main body 1, paper feeding and conveying means 2, an image forming unit 3, a laser optical system 4, a fixing means 5, a discharge tray 61, and the like.
[0012]
The sheet feeding and conveying means 2 includes a sheet feeding cassette 21, a sheet feeding roller 22, a conveying path (23, 25, 27), a pair of registration rollers (24a, 24b), a pair of conveying rollers (26a, 26b), and a pair of discharge rollers (28a , 28b). The paper feed cassette 21 can be pulled out to the right side in the figure, and a part of the casing of the cassette and the printer main body form the transport path 23. The sheet cassette 21 has a sheet stacking plate 211 on which a plurality of sheets are stacked. The sheet stacking plate 211 is loaded with the uppermost sheet by a spring or a lift motor. It is urged to contact the paper roller 22. 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 edge of the sheet. Has a role of transporting the paper from the printer to the image forming means 3. The necessary number of the transport roller pairs (26a, 26b) and the discharge roller pairs (28a, 28b) are laid out in the printer as needed to transport the paper.
[0013]
The image forming unit 3 includes a unit main body 31, 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 stretches a thin tungsten wire of 50 to 100 μm in the longitudinal direction of the photosensitive drum 32 in a shield case opened toward the photosensitive drum 32, and applies a high voltage of about +5 KV to the photosensitive drum 32 to apply the photosensitive drum. The body drum 32 is positively charged. 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 toner image is formed by applying the bias voltage of the developing roller and the potential of the surface of the photosensitive drum to the laser-irradiated portion of the photosensitive drum 32 which is agitated in the developing unit 35 and is positively charged, thereby forming a toner image. Is transferred to the paper conveyed to the nip with the transfer means 36. 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) so as to make the residual potential on the surface uniform. And then prepare for the next series of processes.
[0014]
The inside of the cleaning unit 37 is a collection toner container 371, and the toner scraped off by the rubber blade is accumulated here.
[0015]
In particular, in the image forming section 3, the imaging unit main body 31, the photosensitive drum 32, the main charger 33, the developing means 35, the cleaning means 37, and the toner cartridge 38 are unitized, and as shown in FIG. By opening the right cover 63 and the right cover 63, the printer can be attached to and detached from the printer. The toner cartridge 38 itself can be replaced when the toner runs out.
[0016]
The fixing unit 5 includes a heat roller 52, a heater 53 inside the heat roller 52, a pressure roller 54, a fixing discharge roller pair (55a, 55b), and the like. More specifically, the heat roller 52 is formed by applying a fluorine coat to aluminum or the like having good heat conductivity, and the temperature is controlled to a predetermined temperature required for fixing by incorporating the heater 53 therein. The drive of the heat roller 53 may be driven by the contact from the pressure roller 54, but it is preferable that the heat roller 53 is driven by the pressure roller 54 by meshing with 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 thermal 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.
[0017]
These constituent members are unitized and housed in the fixing housing 51, and a plurality of openings 511 for preventing heat from being stored in the fixing unit 5 are provided at an upper portion of the fixing housing 51. Heat is escaping from here.
[0018]
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.
[0019]
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 feed roller 22 and sent to the conveyance path 23, where the sheets are temporarily stopped by the pair of registration rollers (23a, 23b) and then stopped at a predetermined timing. Then, the unfixed toner is transferred to the nip formed by the photosensitive drum 32 and the transfer means 36 of the image forming means 3 and 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 through the transport path 25. Here, the toner image is fixed on the sheet by being nipped and heated by the nip formed by the heat roller 52 and the pressure roller 54. Thereafter, the sheet is discharged face-down to the discharge tray 61 via the transport path 27.
[0020]
The configuration of the fixing unit 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 is a sectional view taken along line XX shown in FIG.
[0021]
In FIG. 3, the duct 72 is located between the fixing unit 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 intake port of the fixing unit side wall portion 723. A plurality of ventilation holes 725 are provided at a position opposite to the opening 721. The fixing means side wall 723 is made of a sheet metal or the like having good heat conductivity, and is heated by being in contact with the fixing housing 51 of the fixing means 5. On the other hand, the recovered toner container side wall portion 724 is made of a resin having poor thermal conductivity.
[0022]
Next, the flow of air in the fixing unit 5, the collected toner container 371, and the surrounding area will be described 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 outside room temperature air flows while being heated by depriving the fixing unit side wall portion 723 of heat. This air flows into the upper part of the fixing means 5 through the vent 725, flows upward in the drawing while depriving the heat of the fixing housing 51 and the heat rising from the opening 511, and is discharged outside by the exhaust fan 73.
[0023]
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.
[0024]
In this embodiment, two intake fans 71 and one exhaust fan are provided, but the same effect can be obtained by providing any one fan. Although the fixing unit side wall 723 and the collected toner container side wall 724 are formed as separate members, the fixing unit side wall 723 may be made thicker and the collected toner container side wall 724 may be made thinner with the same material. In addition, the plurality of openings 511 of the fixing unit 5 are uniformly arranged in the same size, but the number of openings 511 in the direction in which cold air enters (downward in FIG. 4) is reduced or reduced. If the number of openings 511 in the exhaust direction (upward in FIG. 4) is increased or the number is increased, the unevenness of the temperature of the heat roller 52 is further improved.
[0025]
【The invention's effect】
According to the present invention, since the heat from the fixing unit 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]
1, Printer main body 31; Imaging unit 371; Recovered toner container 5; Fixing means 511; Opening 71; Intake fan 72; Duct 721; Intake port 722; Ventilation space 723; ; Vent 73; exhaust fan

Claims (3)

A fixing unit, a collected toner container, a duct laid out between the fixing unit and the collected toner container, and an image forming apparatus having an in-machine cooling fan that forms a flow of air in the duct.
An air inlet is provided on one side of the duct, and a vent is provided on the opposite side of the wall on the fixing unit side.Air outside the image forming apparatus that has entered from the air inlet moves in the duct, The heat of the fixing casing and the heat rising from the opening formed in the fixing casing flow into the upper part of the fixing means through an air vent provided on the wall of the fixing means on the side opposite to the intake port, and the image is heated. An image forming apparatus, wherein the image is discharged outside the forming apparatus. 2. The image forming apparatus according to claim 1, wherein a wall of the duct on the fixing unit side is made of a material having good heat conductivity, and a side wall surface of the collection container of the duct is made of a material having poor heat conductivity. apparatus. The image forming apparatus according to claim 1, further comprising an exhaust port adjacent to the intake port, wherein the air that flows into the upper portion of the fixing unit through the exhaust port is discharged from the exhaust port.

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