JP2001282061A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing an optical sensor from being soiled by scattered toner and powder dust caused in a developing means or the like, especially, effectively preventing the optical sensor from being soiled because the scattered toner and the powder dust flow in the axial direction of a photoreceptor. SOLUTION: This image forming device is provided with a photoreceptor, the developing means for developing a latent image on the photoreceptor, the optical sensor and a ventilating means for sending air to the optical sensor. In the device, the optical sensor is prevented from being soiled by the toner scattered from the photoreceptor or the developing means or the like with the air sent to the optical sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copier, a facsimile,
The present invention relates to an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art A conventional image forming apparatus as described above includes an apparatus as shown in FIGS. 1 and 2 to which the present invention is applied. The apparatus includes a developing unit 2 for developing a latent image, an optical sensor 3 including a density sensor for detecting the image density of the photoreceptor 1, a blowing unit 4 including a charging fan for blowing the optical sensor 3, and a duct 5. . Reference numeral 6 denotes a cleaning unit for the photoconductor 1, reference numeral 7 denotes an intermediate transfer belt, reference numeral 8 denotes a transfer unit, reference numeral 9 denotes a charger,
Is the detection window, 41 is the scanner cooling fan, 42 is the fixing fan,
Reference numeral 43 denotes a rear fan, 44 denotes a scanner exhaust fan, 45 denotes a sirocco exhaust fan, 46 denotes a transport fan, and arrows indicate air flows.

In such an image formation, scattered toner or dust from the developing means 2 due to use over time causes
There is a problem that the optical sensor 3 becomes dirty and it is difficult to accurately detect the image density, and a density detection error occurs. Therefore, in order to solve the above-mentioned problem, as shown in FIGS. 9 and 10, the optical sensor 3 and the charging charger 9 are blown from the front side or the back side of the image forming apparatus main body by the blowing unit 4 through the duct 5. To this end, an image forming apparatus has been proposed in which air is blown in the directions indicated by arrows 51 and 52 to remove dirt.

[0004]

However, in such an image forming apparatus, as shown in FIG. 9, the airflow in the portion other than the blower moves along the rotation direction of the photoconductor 1, so that the The scattered toner T generated in the means 2 flows downstream of the photosensitive member 1 in the rotation direction,
The accumulated toner T accumulates on the detection window 10 provided in the duct 5 above the optical sensor 3, and the accumulated toner T is blown onto the optical sensor 3 by the air flow, or is broken, thereby contaminating the detection window 10. In addition, there is a problem that the toner drops on the transfer paper and causes toner to drop on the image.

Accordingly, an object of the present invention is to solve the above-described problems of the image forming apparatus, and to prevent the optical sensor from being stained by scattered toner and dust generated in the developing means and the like. It is an object of the present invention to provide an image forming apparatus capable of effectively preventing dust or the like from flowing in the axial direction of a photoconductor and generating stain on an optical sensor.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a photosensitive member, a developing means for developing a latent image on the photosensitive member, an optical sensor, and a blower for blowing air to the optical sensor. 2. An image forming apparatus comprising:
The invention described in (1) is characterized in that the optical sensor is prevented from being contaminated by the toner scattered from the photoconductor or the developing means by the wind blown to the optical sensor.

According to a second aspect of the present invention, the optical sensor comprises:
A blow-off gap is formed between the blower duct and the blower outlet, and the blower gap is provided in the blower duct. It is formed on the downstream side in the rotation direction.

According to a fourth aspect of the present invention, the edge of the outlet of the blower duct is located upstream and downstream in the rotation direction of the photosensitive member.
A partition extending in the longitudinal direction of the photoreceptor is provided so as to protrude, and the invention according to claim 5 is further characterized in that the tip of the downstream partition is larger than the tip of the upstream partition. Are also characterized by being close to the photoreceptor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiments of the present invention shown in the drawings, the same reference numerals are given to the same parts in the conventional example and the embodiments, and the description will be omitted, and different parts will be mainly described. .

FIGS. 3 and 4 show a first embodiment of the present invention. In this embodiment, an optical sensor 3 is provided at an outlet 11 of an air duct 5 with an outlet gap 12 formed. In this embodiment, the airflow sent through the air duct 5 as indicated by the arrow is blocked by the shielding wall 14 provided in the air duct 5, and the air gap is indicated by the arrows 31 and 32.
The toner T that is blown onto the surface of the photoconductor 1 from the air outlet 11 through the air outlets 12 and 13, and the toner T around the air outlet 11 above the optical sensor 3 is diffused by the photoconductor 1 and flows above the optical sensor 3. It is prevented from being soiled or deposited.

The second embodiment shown in FIG.
Is formed only on the downstream side in the rotation direction of the photoreceptor 1, and the airflow flows only in the direction of the developing means 2 on the upstream side in the rotation direction of the photoreceptor 1, as shown by an arrow 32. However, such a difference can effectively prevent the scattering toner generated by the developing unit 2 from flying to the optical sensor 3.

In the third embodiment shown in FIGS. 6 and 7, the edge of the air outlet 11 of the blower duct 5 is located upstream and downstream in the rotation direction of the photoconductor 1 in the longitudinal direction of the photoconductor 1. Extended partition 1
6, 17 are protruding. In such a case, as in the first embodiment, the airflow is blown to the surface of the photoreceptor 1 from the outlet 11 through the blowing gap 12 as shown by arrows 21 and 22. The flow is prevented from flowing on the surface of the photoreceptor 1 in the circumferential direction by the arrow.
As shown in 33 and 34, it flows in the axial direction of the photoconductor 1 and does not flow to the photoconductor 1 and the intermediate transfer belt 7 side.
It is possible to effectively prevent flying toner from flying to the optical sensor 3.

A fourth embodiment shown in FIG. 8 has a downstream partition.
The tip of the partition 17 is closer to the photosensitive member 1 than the tip of the partition 16 on the upstream side, and the distance L,
1 is different from the third embodiment in that L> l. Due to such a difference, the airflow indicated by the arrow 33 to the developing means 2 side is reduced by the airflow indicated by the arrow 22 to the opposite side. The flow rate can be made larger than the air volume, so that flying toner generated by the developing means 2 can be reliably prevented from flying to the optical sensor 3.

[0014]

The present invention is as described above. According to the first aspect of the present invention, the air blown to the optical sensor is
By the toner scattered from the photoreceptor or the developing means,
According to the second aspect of the present invention, the optical sensor forms a blowout gap between the optical sensor and an outlet of the blower duct, and is provided in the blower duct. Has an effect that the periphery of the optical sensor can be prevented from being stained by the scattered toner by spraying in the direction of the developing means by colliding with the surface of the photoconductor.

According to a third aspect of the present invention, the blowing gap is formed on the downstream side in the rotation direction of the photoreceptor, and the fourth aspect of the invention is directed to the photoreceptor at the edge of the outlet of the blower duct. A partition extending in the longitudinal direction of the photoreceptor is provided on the upstream side and the downstream side in the rotational direction of the photoreceptor, so that the blown air flows over the entire longitudinal direction of the photoreceptor and scatters around the optical sensor. There is an effect that contamination by toner can be prevented.

According to the fifth aspect of the present invention, since the leading end of the downstream partition is closer to the photosensitive member than the leading end of the upstream partition, the blown airflow is more upstream in the rotation direction of the photosensitive member. Since it flows, there is an effect that the periphery of the optical sensor can be prevented from being stained by the scattered toner.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is an explanatory diagram of a schematic schematic configuration of the above.

FIG. 3 is a front view of a main part of the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of the same.

FIG. 5 is a sectional view of a portion similar to FIG. 4 of a second embodiment of the present invention.

FIG. 6 is a front view of a main part according to a third embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of the same.

FIG. 8 is a sectional view of a portion similar to FIG. 7 of a fourth embodiment of the present invention.

FIG. 9 is a front view of a main part similar to FIG. 3 of a conventional example of the same kind as the present invention.

FIG. 10 is a partial cross-sectional view of the same.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 Developing means 3 Optical sensor 4 Blowing means 5 Blowing duct 6 Cleaning means 7 Intermediate transfer belt 8 Transfer part 9 Charger 10 Detection window 11 Blow-out 12 Blow-out gap 13 Blow-out gap 14 Shield 16 Partition 17 Partition

Claims (6)

[Claims] In an image forming apparatus including a photoconductor, a developing unit that develops a latent image on the photoconductor, an optical sensor, and a blowing unit that blows air to the optical sensor, the image forming apparatus includes: An image forming apparatus wherein an optical sensor is prevented from being stained by toner scattered from a body or a developing unit. 2. The image forming apparatus according to claim 1, wherein the optical sensor is provided in the air duct such that an air gap is formed between the optical sensor and the air outlet of the air duct. 3. The image forming apparatus according to claim 2, wherein the blowing gap is formed on the downstream side in the rotation direction of the photoconductor. 4. The photoreceptor according to claim 1, wherein a partition extending in the longitudinal direction of the photoconductor is protrudedly provided on an upstream side and a downstream side in the rotation direction of the photoconductor at the edge of the outlet of the air duct. Item 4. The image forming apparatus according to any one of Items 1 to 3. 5. The image forming apparatus according to claim 4, wherein a front end of the downstream partition is closer to the photosensitive member than a front end of the upstream partition. 6. The image forming apparatus according to claim 1, wherein the optical sensor is a density detection sensor that detects an image formed on the surface of the latent image carrier.