JP2000255105A - Image-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a seal glass and optical parts in an optical box from being stained and obtain a good print image quality at all times without frequent maintenance by controlling an air flow in an image-forming apparatus. SOLUTION: An air flow (shown by an arrow) formed between a supply air opening 48A of a supply air duct 48 and an exhaust air opening 50A of an exhaust air duct 50 generates a vortex or negative pressure between a seal glass 36 and a photosensitive body 10. The air is sucked in front of the seal glass 36 by setting an inflow opening 44A of an inflow duct 44 to which the air can flow in, whereby generation of the vortex or negative pressure is prevented. A flow of the air is accordingly prevented from being formed in front of the seal glass 36. Stain is prevented from adhering to the seal glass 36. Even when a projection opening 38 is open, no negative pressure is generated in an optical scanning apparatus and therefore the outside air including dust is prevented from invading the optical scanning apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus such as a laser printer and a digital copier.

[0002]

2. Description of the Related Art As shown in FIG. 4, a sealing glass 36 for sealing a cover 20 and an emission port 64 is provided in an optical box 62 of an optical scanning device 60 for exposing a photoreceptor 10 to light.
The optical members (the polygon mirror 24, the cylinder mirror 34, etc.) are housed in a space substantially enclosed by and while maintaining the positional relationship.

[0003] The optical box 62 is mounted on the main body frame 18, and the optical scanning device 60 is mounted on the main body frame 18.
Is separated from an image forming unit such as the photoconductor 10. An opening 66 is formed in the main body frame 18 only at a portion through which the laser beam passes, and the laser beam emitted from the emission port 38 penetrating the opening 66 passes through the opening 66 so that the photosensitive member It converges to 10.

On the other hand, on the lower surface of the main body frame 18, there is provided an intake duct 48 with an intake port 48A directed toward the photoreceptor 10, and air is blown in by a fan (not shown) arranged on the front side of the drawing. It is. The 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 which is sucked by a fan (not shown) arranged on the back side of the drawing.

[0005] The arrows indicate the air flow in the vicinity of the photoreceptor 10, and the ozone generated when the photoreceptor 10 is charged by the charger 12 is sent to an ozone filter provided in the exhaust duct 50. It functions to send floating toner, discharge products, and the like generated at the time of printing to a filter provided at the exhaust port of the exhaust duct 50, and thereby, the charger 1
2 and various sensors are prevented from being stained.

Incidentally, since the seal glass 36 is removed for cleaning, it is generally arranged near the photoconductor 10. However, since the toner and the discharge products are floating around the photoconductor 10, the entrained airflow A near the photoconductor 10 hits the seal glass 36, and contaminates the seal glass 36. Therefore, there is a problem that the seal glass 36 must be frequently cleaned.

On the other hand, as shown in FIG. 5, by using an air flow from the optical scanning device 68 to the photoreceptor 10 without using a shield glass, toner or the like enters the optical box 72 from the exit port 70. There are things that I tried not to do.

[0008] However, the air sucked from the exit 70 generates a negative pressure in the optical box 72. As a result, the outside air C is sucked through the gap between the covers 20, and fine dust in the air contaminates the optical components, 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 assembling property is extremely poor, which causes a large cost increase.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problem. The present invention controls air flow in an image forming apparatus to remove dirt on seal glass and optical components in an optical box. An object of the present invention is to prevent the occurrence of frequent maintenance and obtain good print quality without frequent maintenance.

[0010]

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 a main body frame, and a photosensitive member is exposed. Blowing means is disposed below the main body frame, and blows floating matters around the photoconductor to an exhaust port.

The air flow generated between the blowing means and the exhaust port causes a vortex or a negative pressure between the output port and the photosensitive member. An air inflow path through which air can flow is provided. Thus, the air is sucked in front of the outlet and no vortex or negative pressure is generated, and no air flow occurs in front of the outlet.

For this reason, when the exit port is sealed with the seal glass, no dirt adheres to the seal glass, and even when the exit port is open, the inside of the optical scanning device is set to a negative pressure. Therefore, 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 output port and the photoconductor.

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 of the gap is formed between the emission port and the photosensitive member. It is characterized by being located between.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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.
The charged photoconductor 10 has a characteristic of lowering the potential of that portion when irradiated with a laser beam. Utilizing this characteristic, the optical scanning device 14 irradiates a laser beam to a portion where toner is to be attached on the photoconductor 10.

Then, the developing device causes the toner to adhere only to the portion where the potential of the photoconductor 10 is lowered. The toner is transferred to an image carrier such as paper by a transfer charger, and is 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 to a laser beam.

Next, an outline of the optical scanning device 14 will be described.

The optical box 16 of the optical scanning device 14 is mounted on a main body frame 18. The upper opening of the optical box 16 is substantially closed by a cover 20, and optical components are stored in the closed space.

In the optical system constituted by this optical component, a laser beam emitted from a laser diode passes through a collimator lens, a cylinder lens, and the like, and passes through a polygon mirror 2.
Reach 4 The polygon mirror 24 is a polygonal prism having a plurality of mirror surfaces on a side surface, and is rotated at high speed by a scanner motor 26.

The deflection of the polygon mirror 24 causes the laser beam to obtain a swing angle, and the Fθ lenses 28, 3
0, the light passes through the plane mirror 32, the cylinder mirror 34, and the dustproof seal glass 36, and scans the photosensitive member 10. The laser diode driver board controls the light emission amount and the light emission time by a laser diode driver substrate, modulates the laser diode according to an image signal from the main body, and records an image on the photoreceptor 10.

On the other hand, the bottom plate 40 of the optical box 16 has a raised 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. This emission port 38 is covered with a seal glass 36.

On the right side of the opening 42, a crank-shaped inflow duct 44 is disposed.
It faces a path connecting the light exit 38, the opening 42, and the photoconductor 10. An air filter 46 is attached to a suction port 44B of the inflow duct 44, and clean air flows in from an inflow port 44A.

Further, on the lower surface of the main body frame 18, on the left side of the photoreceptor 10, there is provided an intake duct 48 with an intake port 48A directed toward the photoreceptor 10, and air is blown out by a fan (not shown). You. An exhaust duct 50 is provided on the right side of the photoconductor 10 with the exhaust port 50A facing the intake port 48A. This exhaust duct 50
The fan extends to the front and back sides of the paper, and a suction force is applied to the exhaust port 50 </ b> A by a fan (not shown) arranged on the back side.

The air blown out from the suction port 48A forms an airflow (indicated by an arrow) toward the discharge port 50A, and removes floating toner and the like near the photoreceptor 10 from the discharge duct 50A.
To prevent contamination of the charger 12 and sensors.

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 a direction along the optical path from the seal glass 36 to the photoconductor 10. However, by setting the flow rate of the inflow duct 44 to be larger than the flow rate of the intake duct 48, air is sucked from the inflow duct 44, and no air flow occurs near the seal glass 36.

Therefore, no dirt adheres to the seal glass 36 and the suction force in the gap between the seal glasses 36 is very small. It does not contaminate parts.

In this embodiment, the outlet 38 is sealed with the sealing glass 36. However, if the size of the outlet 38 is made sufficiently smaller than the size of the inlet 44A of the inflow duct 44, the outlet 38 can be used. Therefore, the flow resistance increases, so that the flow of air to the optical scanning device 14 can be minimized. Therefore, the cylinder mirror 3 which is the final optical component
4 is hardly stained.

Next, an image forming apparatus according to a second embodiment will be described.

As shown in FIGS. 2 and 3, in the second embodiment, the optical box 16 is supported by the leg plate 54 and the bottom plate 40.
A gap 56 as an air inflow passage is formed between the main body frame 18 and the main body frame 18. The gap 56A of this gap 56
The (air inlet) faces a path connecting the emission port 38, the opening 42, and the photoreceptor 10, and the air is sucked from the gap 56 by the air flow created by the intake duct 48, as in the first embodiment. In the vicinity of the seal glass 36, no air flow occurs.

Therefore, dirt does not adhere to the seal glass 36, and outside air does not enter the optical scanning device 14 from the gap of the cover 20 to stain the optical components.

Further, the larger the gap 56 between the bottom plate 40 and the main body frame 18 is, the higher the ratio of the sucked air becomes. However, since the optical scanning device uses a laser beam,
If the gap 56 is increased, the worker may be exposed to the laser beam during repair work.

For this reason, for example, the gap is desirably a size that does not allow a finger to be inserted, for example, 12 mm or less. Also in this embodiment, an example in which a seal glass is mounted has been described. However, as in the case of the second embodiment, the seal glass is not required as long as the emission port is sufficiently large.

Also, by creating an air flow in the gap, the IC5
Electronic components such as 8 can also be cooled.

[0034]

According to the present invention, the air flow in the image forming apparatus is controlled. For this reason, it is possible to prevent contamination of the seal glass and optical components in the optical box, and it is possible to always obtain 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 illustrating 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 Outgoing port 44 Inflow duct (air inflow path) 56 Crevice (air inflow path)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C362 DA14 EA17 2H071 DA02 DA05 DA15 EA04 EA10 5C062 AA05 AB35 5C072 AA03 BA20 CA10 DA01 HA02 HA12 XA05

Claims (3)

[Claims] 1. An optical scanning device attached to a main body frame, a photoconductor exposed by a laser beam emitted from an emission port of the optical scanning device, and a floating substance arranged below the main body frame and surrounding the photoconductor. An image forming apparatus, comprising: a blowing unit that blows air to an exhaust port, wherein an air inflow path through which air can flow is provided between the emission port and the photoconductor. 2. The image forming apparatus according to claim 1, wherein the air inflow path is a duct having an inflow port located between the emission port and the photoconductor. 3. The air inlet 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 according to claim 1.