JP3656448B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a laser printer and a digital copying machine.
[0002]
[Prior art]
As shown in FIG. 4, in the optical box 62 of the optical scanning device 60 that exposes the photosensitive member 10, that is, in a space that is substantially sealed with a seal glass 36 that seals the cover 20 and the emission port 64. Optical members (polygon mirror 24, cylinder mirror 34, etc.) are housed in a positional relationship.
[0003]
The optical box 62 is attached to the main body frame 18, and the optical scanning device 60 is partitioned from the image forming unit such as the photoreceptor 10 by the main body frame 18. The main body frame 18 is formed with an opening 66 only at a portion through which the laser beam passes, and the laser beam emitted from the emission port 38 that has penetrated the opening 66 passes through the opening 66 and passes through the photosensitive member. It converges to 10.
[0004]
On the other hand, an air intake duct 48 is provided on the lower surface of the main body frame 18 with the air inlet 48A facing the photosensitive member 10 side, and air is blown in by a fan (not shown) disposed on the front side of the paper surface. Air in the intake duct 48 flows in the direction of the arrow from the intake port 48A to the exhaust port 50A of the exhaust duct 50 that is sucked by a fan (not shown) disposed on the back side of the drawing.
[0005]
This arrow indicates the air flow in the vicinity of the photoconductor 10, and ozone generated when the photoconductor 10 is charged by the charger 12 is sent to an ozone filter provided in the exhaust duct 50 or generated during printing. The function is to send floating toner, discharge products, and the like to a filter provided at the exhaust port of the exhaust duct 50, thereby preventing the charger 12 and various sensors from being contaminated.
[0006]
By the way, since the sealing glass 36 is removed for cleaning, it is generally arranged in the vicinity of the photoreceptor 10. However, since toner and discharge products are floating around the photoconductor 10, the entrained air flow A near the photoconductor 10 hits the seal glass 36 and stains the seal glass 36. For this reason, there is a problem that the sealing glass 36 must be frequently cleaned.
[0007]
On the other hand, as shown in FIG. 5, toner or the like does not enter the optical box 72 from the exit port 70 by creating an air flow from the optical scanning device 68 toward the photoconductor 10 without using a shield glass. There is what I did.
[0008]
However, the air sucked out from the emission port 70 generates a negative pressure in the optical box 72. As a result, the outside air C is sucked in through the gap of the cover 20, and fine dust in the atmosphere contaminates the optical component, causing a reduction in the amount of light. For this reason, it is necessary to close the gap of the cover 20 with an elastic member such as urethane, and the assemblability is very poor, which causes a large cost increase.
[0009]
[Problems to be solved by the invention]
The present invention has been made to solve the above problems, and by controlling the air flow in the image forming apparatus, the optical components in the seal glass and the optical box are prevented from being contaminated, without frequent maintenance. It is an object to always obtain a good print image quality.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, a laser beam is emitted from an emission port of an optical scanning device attached to the main body frame, and the photosensitive member is exposed. Blowing means is arranged below the main body frame so that floating matter around the photosensitive member is blown out to the exhaust port.
[0011]
Due to the air flow generated between the blowing means and the exhaust port, a vortex or a negative pressure is generated between the emission port and the photosensitive member. By providing an air inflow passage through which air can flow, Air is sucked in front of the exit and no vortex or negative pressure is generated, and no air flow occurs in front of the exit.
[0012]
For this reason, when the exit port is sealed with the seal glass, the seal glass is not contaminated, and even if the exit port is open, the inside of the optical scanning device is not made negative. Therefore, the outside air containing dust does not enter the optical scanning device.
[0013]
The invention described in claim 2 is characterized in that the air inflow path is a duct whose inflow port is located between the exit port and the photosensitive member.
[0014]
According to a third aspect of the present invention, the air inflow path is a gap formed between the main body frame and the optical scanning device, and a gap opening of the gap is located between the emission port and the photoconductor. It is characterized by doing.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image forming apparatus according to an embodiment will be described with reference to the drawings.
(Schematic configuration of image forming apparatus)
As shown in FIG. 1, the photoconductor 10 that is the body to be scanned is charged by a charger 12. The charged photoconductor 10 has a characteristic of lowering the potential of the portion when irradiated with a laser beam. Utilizing this characteristic, the optical scanning device 14 irradiates the laser beam to the portion where the toner is adhered on the photoconductor 10.
[0016]
Then, the toner is attached only to the portion where the developing device has the potential of the photoreceptor 10 lowered. The toner is transferred to an image carrier such as paper by a transfer charger, and melted and fixed to the image carrier by a fixing device. The toner remaining on the photoconductor 10 is removed by a cleaner, and the photoconductor 10 is charged again and exposed with a laser beam.
[0017]
Next, an outline of the optical scanning device 14 will be described.
[0018]
The optical box 16 of the optical scanning device 14 is attached to the main body frame 18. The upper opening of the optical box 16 is substantially sealed with a cover 20, and optical components are accommodated in this sealed space.
[0019]
In the optical system constituted by this optical component, the laser beam emitted from the laser diode reaches the polygon mirror 24 through the collimator lens, the cylinder lens, and the like. The polygon mirror 24 is a polygonal column having a plurality of mirror surfaces on its side surface and is rotated at high speed by a scanner motor 26.
[0020]
The deflection of the polygon mirror 24 causes the laser beam to obtain a swing angle, and scans the photoreceptor 10 through the Fθ lenses 28 and 30, the plane mirror 32, the cylinder mirror 34, and the dust-proof seal glass 36. In the laser diode, the light emission amount and the light emission time are controlled by a laser diode driver substrate, and the laser diode is modulated in accordance with an image signal from the main body side to record an image on the photosensitive member 10.
[0021]
On the other hand, the bottom plate 40 of the optical box 16 is raised at a portion facing the opening 42 of the main body frame 18 through which the laser beam passes, and an emission port 38 is formed in this portion. The exit port 38 is covered with a seal glass 36.
[0022]
A crank-shaped inflow duct 44 is disposed on the right side of the opening 42, and the inlet 44 </ b> A faces a path connecting the emission port 38, the opening 42, and the photoconductor 10. An air filter 46 is attached to the suction port 44B of the inflow duct 44, and purified air flows from the inflow port 44A.
[0023]
Further, on the lower surface of the main body frame 18, an air intake duct 48 is provided on the left side of the photoconductor 10 with the air intake port 48A facing the photoconductor 10 side, and air is blown out by a fan (not shown). Further, an exhaust duct 50 is provided on the right side of the photoconductor 10 with the exhaust port 50A facing the intake port 48A. The exhaust duct 50 extends to the front and back surfaces of the paper, and applies a suction force to the exhaust port 50A by a fan (not shown) disposed on the back side.
[0024]
Then, the air blown out from the intake port 48A forms an air flow (indicated by an arrow) toward the exhaust port 50A, and floating toner or the like in the vicinity of the photoconductor 10 is flowed into the exhaust duct 50, and the charger 12 and sensors. Prevent dirt.
[0025]
On the other hand, due to the air flow created by the intake duct 48, an air flow is formed between the seal glass 36 and the photoconductor 10 in the direction along the optical path from the seal glass 36 to the photoconductor 10 . As a result, air is sucked from the inflow duct 44, air near the seal glass 36 is sucked, and no air flow is generated in front of the seal glass 36 .
[0026]
Accordingly, no dirt adheres to the seal glass 36, and the suction force in the gap of the seal glass 36 is extremely small. Therefore, outside air enters the optical scanning device 14 through the gap of the cover 20 and stains the optical components. There is nothing.
[0027]
In this embodiment, the exit port 38 is sealed with the sealing glass 36. However, if the size of the exit port 38 is made sufficiently smaller than the size of the inflow port 44A of the inflow duct 44, the flow rate resistance at the exit port 38 is reduced. Therefore, the flow of air to the optical scanning device 14 can be minimized. For this reason, the cylinder mirror 34 which is the final optical component is hardly soiled.
[0028]
Next, an image forming apparatus according to the second embodiment will be described.
[0029]
As shown in FIGS. 2 and 3, in the second embodiment, the optical box 16 is supported by the leg plate 54, and a gap 56 as an air inflow path is formed between the bottom plate 40 and the main body frame 18. . A gap port 56A (air inlet) of the gap 56 faces a path connecting the emission port 38, the opening 42, and the photosensitive member 10, and, as in the first embodiment, the air flow created by the intake duct 48 Air is sucked from the gap 56 and no air flows in the vicinity of the seal glass 36.
[0030]
For this reason, dirt does not adhere to the seal glass 36, and the outside air does not enter the optical scanning device 14 through the gap of the cover 20 to contaminate the optical components.
[0031]
Moreover, since the ratio of the air sucked out becomes larger when the gap 56 between the bottom plate 40 and the main body frame 18 is made as large as possible, a high effect can be expected. However, since the optical scanning device uses a laser beam, if the gap 56 is increased, an operator may be exposed to the laser beam during repair work.
[0032]
For this reason, for example, it is desirable that the gap is not large enough to insert a finger, for example, 12 mm or less. Also, in this embodiment, the example in which the seal glass is mounted has been described. However, as in the second embodiment, the seal glass is not required if the exit port is sufficiently large.
[0033]
Further, an electronic component such as the IC 58 can be cooled by creating an air flow in the gap.
[0034]
【The invention's effect】
Since the present invention has the above configuration, the air flow in the image forming apparatus is controlled. For this reason, it is possible to prevent the sealing glass and the optical components in the optical box from being stained, and it is possible to always obtain a good print image quality without frequent maintenance.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an image forming apparatus according to a first embodiment.
FIG. 2 is a side sectional view showing an image forming apparatus according to a second embodiment.
FIG. 3 is a perspective view showing a gap of an image forming apparatus according to a second embodiment.
FIG. 4 is a side sectional view showing a conventional image forming apparatus.
FIG. 5 is a side sectional view showing a conventional image forming apparatus.
[Explanation of symbols]
36 Seal glass 38 Outlet 44 Inflow duct (air inflow path)
56 Clearance (air inflow path)

Claims (3)

An optical scanning device attached to the main body frame, a photoconductor exposed by a laser beam emitted from the output port of the optical scanning device, and a blowout that blows out floating substances arranged below the main body frame around the photoconductor to the exhaust port An image forming apparatus comprising:
An air inflow path through which air can flow is provided between the emission port and the photosensitive member, and air in front of the emission port is sucked by an air flow generated between the blowing means and the exhaust port. An image forming apparatus.   The image forming apparatus according to claim 1, wherein the air inflow path is a duct having an inflow port positioned between the emission port and the photosensitive member.   2. The air inflow path is a gap formed between the main body frame and the optical scanning device, and a gap opening of the gap is located between the emission port and the photoconductor. The image forming apparatus described in 1.

Images