JPH0451262A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the rising of a temp. inside a machine by means of a thermal fixing device and simultaneously to easily carry out the processing of paper jamming in a paper ejecting device by arranging an exhaust duct on the upper part of the thermal fixing device, and providing a shielding plate capable of turning on the lower side of the exhaust duct and between the thermal fixing device and the paper ejecting device. CONSTITUTION:Hot air emitted from the thermal fixing device 21 and air incorporating ozone blown off from the vicinity of a transfer charger 20 by an air intake fan 34 are mainly sucked from an air intake hole 49 to the exhaust duct 44. On the other hand, the air incorporating the ozone in the vicinity of an electrifying charger 17 is mainly sucked from an air intake hole 50 into the exhaust duct 44, and forcibly exhausted outside the machine by an exhaust fan 48. At this time, the ozone is removed from a filter 47. Thus, the shielding plate 45 shields an air flowing path leading to the paper ejecting device 22, during exhausting, so that the exhausting of the hot air and an ozone removing action do not deteriorate by the sucking of outside air from the exhaust hole. When a sheet is jammed in the paper ejecting device, an upper part unit 10a is released, the shielding plate 45 is turned, and the sheet 14 is easily taken out between a paper ejecting guide 25 and a rib.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic image forming apparatuses such as laser printers, laser copying machines, and laser facsimiles, and particularly to internal air exhaust structures therein.

For example, Japanese Patent Application Laid-Open No. 63-66583 discloses an image forming apparatus in which a sheet on which a toner image is thermally fixed is discharged to a stack section at the top of the main body by a sheet discharge device. In order to suppress the rise in temperature inside the machine, a paper discharge guide member of a paper discharge device is provided with a large number of holes that allow air to flow to the heat fixing device.

On the other hand, Japanese Utility Model Application Publication No. 62-43360 discloses an image forming apparatus in which the upper unit of the main body is rotatable with respect to the lower unit of the main unit about the fulcrum of the upper and lower units, and in which the paper ejection port of the upper unit of the main unit is arranged from the paper stacking section. Also described is one provided on the fulcrum side of the upper and lower units.

Problems to be Solved by the Invention However, in the method disclosed in Japanese Unexamined Patent Publication No. 63-66583, even if a fan is provided for forced exhaust, air is taken in through the many holes in the paper ejection guide member. ,
High temperature air near the heat fixing device is not exhausted, making it impossible to create an efficient air flow for exhausting hot air.

On the other hand, in the device disclosed in Japanese Utility Model Application No. 62-43360, the temperature rise near the heat fixing device can be prevented by a fan, but when a paper jam occurs, the guide member of the paper ejection device remains fixed even if the upper unit of the main body is opened. Therefore, it is difficult to remove jammed paper.

An object of the present invention is to solve the above-mentioned problems, effectively prevent the temperature rise inside the machine due to the heat fixing device, and
An object of the present invention is to provide an image forming apparatus that can easily handle paper jams in a paper discharge device leading to a paper discharge port.

Means for Solving the Problems The present invention transfers a toner image formed on a photoreceptor onto a sheet of paper, fixes it with a thermal fixing device, transports the sheet with a paper ejecting device, and transfers the toner image formed on a photoconductor onto a sheet of paper, then transports the sheet with a paper ejecting device and places the toner image on an openable upper part of the main body. In an image forming apparatus that ejects paper from a paper ejection port provided therein, an exhaust duct is arranged above the heat fixing device, and a shielding plate is rotated below the exhaust duct and between the heat fixing device and the paper ejection device. It is characterized by being movable.

The hot air near the thermal fixing device is exhausted through the exhaust duct. Even if the exhaust is forced by a fan, the shielding plate prevents outside air from being sucked in through the paper discharge port, and the hot air is efficiently discharged.

Since the shielding plate is rotatable, it is easy to clear a paper jam.

Example Next, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall internal configuration diagram of a laser printer according to the present invention. In the figure, 10 is a printer main body divided into an upper unit 10a and a lower unit 10b, and the upper unit 10a is pivotably pivoted (openable) about a pin 11 with respect to the lower unit 10b by a bracket (not shown) provided thereon. It is worn. Reference numeral 12 denotes a paper feed cassette that is removably loaded in the lower part of the printer main body 10. The paper 14 fed from the paper feed cassette 12 by the paper feed roller 13 is conveyed to the lower side of the belt-shaped photoreceptor 16 by a pair of registration rollers 15 with timing. The photoreceptor 16 is rotationally driven in the direction of the arrow,
At this time, the surface of the photoreceptor 1 is uniformly charged by the IT charger 17, and the photoreceptor 1 is charged based on the optical signal from the optical unit 18.
An electrostatic latent image is formed on 6. This latent image is a developing device! 1
At step 9, the toner is used to make a visible image, and this visible image is transferred by the transfer charger 20 onto the paper 14 that has been conveyed. The paper 14 is conveyed to a thermal fixing device 121 and a visible image is fixed thereon. Then, the paper 14 that has exited the heat fixing device 1121 is transferred to the lower paper ejection roller pair 2 of the paper ejection device 11f22.
Immediately after the paper has passed between 3 and 3, the switching claw 24 switches the paper ejection direction up and down. and.

When the paper is switched upward, it is guided by the paper ejection guides 25 and 26, and is transported from the upper paper ejection port 29 by the upper paper ejection roller 27 and the pinch roller 28 to the stack section 30 on the upper surface of the upper unit 10a with the image side facing down. be discharged. Further, when the switch is made downward, the paper 14 is ejected backward from the lower paper ejection port 31 by the lower paper ejection roller 23 with the image side facing up. One roller of the pair of lower paper discharge rollers 23 and the upper paper discharge roller 27 are mounted between the ribs 25a of the paper discharge guide 25, as shown in FIG.

On the other hand, after the visible image has been transferred, the photoreceptor 16 is cleaned of residual toner by a cleaning device 132, and is further neutralized by light from a static eliminator 33 in preparation for the first image forming cycle.

An intake fan 34 is disposed below the transfer charger 20, and after cooling the power supply unit 36 with air sucked in from an intake port 35 provided at the bottom of the lower unit 10b, the air is blown around the transfer charger 20. Ozone is discharged outside the machine as described below.

FIG. 2 is a schematic diagram of the interior of the upper unit 10a in an open state, and FIG. 3 is a perspective view of its exterior. Photoreceptor 16 and cleaning device! 32 is unitized and can be attached to and detached from the upper unit 10a. The optical unit 18, the static eliminator Wt33, and the charger 17 also include
It is attached to the upper unit 10a side. On the other hand, an operation panel 3 is provided on the upper cover 37 on the lower unit 10b side.
8, and a front door 39 is hinged to the lower side thereof so as to be openable and closable. The front door 39 is provided with a paper feed port 40 for manual feed and an optional paper feed tray.
A paper feed guide 41 for guiding the paper 14 fed by the paper feed roller 13 is provided on the inner surface of the paper feed guide 41 . Developing device f19
, open the front door 39 and replace it. 42 in Figure 3
43 is a controller, and 43 is a card insertion slot for inserting an IC card.

Further, an exhaust duct 44 is provided on the upper unit 10a side. A shielding plate (flap) 45 is rotatably attached to the lower side edge of the exhaust duct 44 by a shaft 46 . When the upper unit 10a is closed as shown in FIG. 1, the exhaust duct 44 is located above the heat fixing device [t21]. The shielding plate 45 hangs down from the exhaust duct 44 and is connected to the heat fixing device! 121 and the heat fixing device! 21 and the paper discharge guide 25.

FIG. 5 shows the exhaust duct 44 in detail. Exhaust duct 4
One end of 4 is connected to the exhaust fan 4 via an ozone filter 47.
It is connected to 8. A large number of intake holes 49 and 50 are provided at the bottom and side portions of the exhaust duct 44. These intake holes 49 and 50 become larger as they move away from the exhaust fan 48 so that air can be efficiently sucked into the exhaust duct 44.

Therefore, the hot air emitted from the heat fixing device 21 and the ozone-containing air blown from the vicinity of the transfer charger 20 by the intake fan 34 are mainly sucked into the exhaust duct 44 through the intake hole 49, and the ozone near the charger 17 is also absorbed. The air contained therein is mainly drawn into the exhaust duct 44 through the intake hole 50 and is forcibly discharged to the outside of the machine by the exhaust fan 48. At that time, ozone is filtered through ozone filter 4.
removed by 7. During such exhaustion, the shielding plate 45
The exhaust duct 44 and the heat fixing device m! Since the air flow path leading to the paper discharge device 22 is blocked between the upper unit 10a and the upper unit 10a, the air flow path leading to the paper discharge device 22 is blocked, so that outside air is When inhaled, the hot air exhaust and ozone removal effects described above will not be diminished.

If a paper jam occurs in the paper output bag [22, remove the upper unit 1
0a as shown in FIG. 2 and rotate the shielding plate 45 in the direction of the arrow, the paper 14 can be easily removed by inserting a finger between the ribs 25a of the paper discharge guide 25.

FIG. 6 shows another embodiment of the exhaust duct 44 and the shielding plate 45,
The shielding plate 45 is integrally molded with resin and the exhaust duct 44, and is configured to be bent and rotated in a cut-shaped groove 51.

FIG. 7 shows yet another embodiment, in which two ribs 53 are integrally provided vertically on the lower surface of the frame 52 of the optical unit 18, and a cover plate 54 is attached to the lower side of the ribs 53 to form an exhaust duct 44. A large number of intake holes 49 and 5o are provided in the lid plate 54 and one rib 53, and a shielding plate 45 is vertically mounted on the frame 52 so as to be freely rotatable around a shaft 46.

Hoho! According to the present invention, a shielding plate is provided below the exhaust duct between the heat fixing device and the paper discharge device, so that outside air is not drawn in from the paper discharge port or the exhaust hole of the cover. Hot air and ozone inside the machine can be reliably guided to the exhaust duct, preventing temperature rise inside the machine and removing ozone accurately.

Furthermore, since the shielding plate is made rotatable, it is easy to observe and remove jammed paper generated in the paper ejection device leading to the paper ejection port.

[Brief explanation of the drawing]

FIG. 1 is an overall internal configuration diagram of a laser printer that is an embodiment of the present invention, FIG. 2 is a schematic diagram of the interior of the printer main body when the upper unit is opened, and FIG. 3 is an external perspective view of the printer.
Figure 4 is a partial perspective view of the paper ejection guide, Figure 5 is a partially cutaway perspective view of the exhaust duct and shielding plate, and Figures 6 and 7 are perspective views and sectional views showing other examples, respectively. be. 10...Printer main body, 10a...
...Upper unit, 16...Photoreceptor, 21...Heat fixing device, 22...
... Paper discharge device, 29 ... Paper discharge port,
44...Exhaust duct, 45...
···Shield. Figure +2 Figure

Claims (1)

[Claims] Image formation involves transferring the toner image formed on the photoreceptor onto paper, fixing it with a thermal fixing device, and then conveying the paper with a paper ejection device and ejecting it from the paper ejection port provided at the top of the main body, which can be opened. The apparatus is characterized in that an exhaust duct is arranged above the heat fixing device, and a shielding plate is rotatably provided below the exhaust duct and between the heat fixing device and the paper ejecting device. An image forming apparatus.