JPS6298367A - Image forming device - Google Patents

Abstract

PURPOSE:To positively prevent toner from sticking on an electrostatic charger, discharger, or image formation optical system, etc., by allowing an air flow to run in a peripheral space extending from the downstream side of a cleaning member to the upstream side of a developing device in the rotating direction of an image carrier. CONSTITUTION:When a fan 26 rotates, scattered toner produced in a developing device 2 and magnetic toner suspended nearby pass a space position opposite a photosensitive drum 1 together with the air flow because of the suctional force of the fan. In this case, they are attracted by a magnet body 20 and then only air is sucked into a unit body 4. Part of the air sucked into the unit body 4 passes through the grid part 6a and discharge wire 6b in the charger 6 to clean up them and is then discharged from the unit body 4 through a discharge hole 18. The remaining air passes through the periphery of a photoconductor 5 and discharged from the unit body 4 through a discharge hole 18. A discharging lamp 17, on the other hand, is cleaned up with the cleaning air which is right after being discharged through the discharge hole 18. A magnet body 16 catches toner fallen by a cleaning blade 13 and prevents it from scattering out.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Application in Industry-1-" The present invention uses magnetic toner to convert an electrostatic latent image formed on a photoreceptor drum or other image IX1 in a copier, printer, facsimile, etc. This relates to an image forming apparatus that uses a magnetic toner to efficiently capture magnetic toner scattered or scattered around a photoreceptor, and to reduce image clarity caused by adhesion of the magnetic toner. 1--Regarding an image forming apparatus capable of preventing

"Conventional technology" Conventionally, there has been a
Image forming apparatuses that are equipped with an imaging optical system, a developing device, a transfer device, a cleaning member, a static eliminator, and an i7 electric device and that transfer and form a predetermined image onto a recording medium by an electrophotographic process are known. In order to improve tonality and image clarity, toner with extremely fine particles (5 to 30wII+), especially magnetic toner, is generally used, but when such a toner with 411 particles is used, it may cause problems during development and When cleaning the toner remaining on the photoreceptor drum after transfer, the toner scatters and adheres to the various peripheral devices as the float moves around the photoreceptor drum along the airflow in the device, Toner contamination may occur.

In particular, if toner adheres to the imaging optical system, charger, or static eliminator, it will immediately lead to low image brightness, unstable images, and even more complicated maintenance. The functions 1-, 19, and 19 cannot be performed, and since both of them are opened on the circumferential side of the photoreceptor drum,
No. 1111, it is completely defenseless against the adhesion of floating toner.

However, since the floating toner generally has an electrostatic charge;
2Electric parts such as electric appliances and static eliminators, and also the above]・ner and;i?
It is easy to adhere to the imaging optical system, the emission surface of the eraser, etc., which are made of materials located on the surface of the electronic system 111.

Therefore, it is extremely important to prevent toner from adhering to such parts.

However, conventional technology requires floating ML for all of the above parts.
There is no technology that completely prevents the adhesion of toner, but it is possible to eliminate the source of toner scattering by placing a toner capture member near the developing device and cleaning member that cause floating toner. ('2) In addition, while allowing the generation of floating toner, toner adhesion has a large effect on image formation, especially on the imaging optical system. ``The only technology that attempts to prevent toner adhesion (hereinafter referred to as toner adhesion prevention technology) exists.

Among the techniques adopting the former configuration, techniques similar to the present invention include, for example, the inlet and outlet portions (1-stream side and r-stream side) of the phenomenon container housing on the side facing the photoreceptor drum.
A sealing magnet is provided on the surface of the developer container to prevent toner from scattering outside the developer container (Utility Model Application No. 58-133157), and the cleaning member and receiver that come into contact with the surface of the photoreceptor drum are placed below the sheet. A magnet body is arranged so as to face the cleaning member etc. and maintain a substantially horizontal state, and the magnet body is configured to catch residual toner that has fallen from the cleaning member etc. (actual opening/closing 58). -10
463';) hJ- is present.

"Problems to be Solved by the Invention" However, all of the above-mentioned prior art attempts to cause the magnetic body to absorb and trap toner that scatters or falls outside from the toner accumulation area.-11- Toner that is scattered outside or inside the device when replacing toner or transferring to a recording medium is captured as a collateral! However, it is not possible to completely eliminate the above-mentioned problems.

In addition, as a technique for replacing toner (1), a corona emitting device is placed near the exit surface of the imaging optical system to prevent contamination of the end surface, and the ion flow generated from the discharge device is placed at 1, 1. , which repels floating toner near the exit surface side and prevents toner adhesion (IF) (Utility Model No. 56-110450-
;-) etc., but since such technology uses a corona discharger, it cannot be used for anything other than optical systems, and it is impossible to use toner in various individual devices. Adding a means
19 becomes 11, which goes against the demand for miniaturization.

The present invention focuses on the primary yellow R where toner adhesion affects image formation.
The side facing the photoreceptor drum of the R product, that is, the exit surface of the optical system (17) (Ensures technology that completely prevents floating toner from adhering to the electrode part of the electric appliance). do.

``Summary of the Invention'' The present invention is configured so that an air current can pass through the surrounding space extending from the cleaning member to the developing device to the downstream side along the rotational direction of the image 11i. Point 1,? ) A magnet is arranged at the inlet end where the airflow is introduced into the surrounding space.

As a result, when an air flow containing floating magnetic toner is introduced into the surrounding space, the floating toner is attracted by the magnetic body, and only 41 clean air flows into the surrounding space. be done.

Then, the clean air passes around the charger and static eliminator installed in the surrounding space, and removes the dust attached to these and the slight floating particles that accidentally adhered to the toner, and discharges the dust to the outside. do.

Since the cleaning function is always activated by the clean air flow, the clean state of the various devices is always maintained.

Note that when the present invention is applied to a copying machine, the old toner 71 is likely to form an image in the surrounding space, causing a problem in static elimination! :
(2) It is preferable to accommodate a focusing optical system for forming a latent image on the image carrier, and when the present invention is applied to a laser printer, the latent image is formed on the image carrier. Since the imaging lens system that forms an image is generally arranged in a hermetically sealed manner within the optical scanning unit, a static eliminator, a charger, and the like may be housed in the surrounding space.

Therefore, the J%C side on the developing device described in the above essential component (2) does not necessarily refer to the area between the latent image forming position and the developing position, but also to the position further from the latent image forming position on the A12 electric side. include.

In addition, the entrance end where the magnet is placed is located at the image 1 as shown in the example below.
! 1. It is not necessary to form it at a position facing the holder, but it may be formed at a space above it.

Furthermore, the surrounding space does not refer only to a closed space surrounded by a frame, but may also be an open space as long as the airflow flows in one direction.

In a preferred embodiment of the present invention, a second magnet is disposed on the downstream side of the cleaning member so as to face the image carrier, thereby extracting the toner that has fallen from the cleaning member and removing the scattered toner. It can be actively captured.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. It's nothing more than that.

FIG. 1 shows a sectional view of essential parts of a laser printer to which the present invention is applied.

In the figure, reference numeral 1 denotes a photoconductor drum l that rotates in the direction of the arrow, and around it, a developing device 2, a transfer device 3, a cleaning device 9, a photoconductor for static elimination 5, a band TL device 6, etc. are arranged in order along the rotation direction. A unit body 4 is disposed in which a unit body 4 is integrally assembled, and an optical scanning unit 4 fixed at a predetermined position by a support wall 7 is provided in a two-way space between the belt unit 6 and the developing unit 2. A unit 8 is disposed, and the laser beam emitted from the optical scanning unit 8 is imaged on the photoreceptor drum lJZ to form an electrostatic latent image.
; After forming an L image, it is transferred to recording paper and image formation is performed based on a known electrophotographic process. Note that IO is a transfer paper conveyance path, and 11 is a registration roller.

The second body 4 includes a substantially U-shaped housing 12 with an opening on the side facing the photoreceptor drum 1, and a cleaning device housed in the housing 2; n9. It consists of a main light guide 5 and a charger 6.

The cleaning device 9 includes a cleaning blade 13 which is made of a plate-shaped rubber member and whose tip is brought into contact with the photoreceptor drum l, and which is disposed below the blade 13 and removes residual toner scraped off by the cleaning blade 13. It is composed of a storage section 14 in which the liquid is stored quietly, and a conveying screw portion 15 disposed within the storage section 14 in parallel with one axis of the photoreceptor drum.

A thin plate-like magnet 16 is fixed on the opposite side of the storage section 14 to the population side of the housing 12 facing the photoreceptor drum l.

The magnet body 16 is formed of a rubber magnet plate with a wall thickness of about 11 mm, and has a magnetic flux density of about 300 to 1000 Gauss with N-3 poles sequentially arranged along the long hair direction on the side facing the photosensitive drum l. A multi-pole magnetized surface with 12, while the housing 12 is tilted and 33 is! /I Make the back side in contact with the non-cyelamagnetic surface.

As shown in FIG. 2, the magnet body 16 described in 1i② has an internal angle α of 20 to 301 It is installed at a predetermined angle #l so that it falls within the range of (2), and the facing distance between the tip position closest to the photoreceptor drum l on the tip side of the magnet 1G and the circumferential surface of the drum 1 is 0.5 to 1.0.
Set to a range of 1.

The light guide 5 for static elimination is formed of an acrylic plate, and the light guide 5 is made of an acrylic plate.
The distal end thereof faces the photoreceptor drum 1, and the proximal end thereof extends to the rear position of the housing 12, and faces the static elimination lamp 17 disposed at the rear position.

As a result, the light source from the charge removal lamp 17 is focused by the charge removal light guide 5 and guided to the photoreceptor drum 1 position, allowing efficient charge removal to be performed.

Further, an exhaust hole 18 is formed in the housing 12 around the base end side of the light guide 5 facing the static elimination lamp 17, so that the airflow introduced into the unit body 4 can be exhausted to the outside.

・11? The electric appliance B has a slint hole 19 formed in the inner part of the partition wall on the side of the static eliminating circumferential optical conductor 5, and the airflow introduced into the unit body 4 is connected to the grid part 6a in the charger 6 and the discharge wire 6.
While passing through b +iiij pickpocket 5. It is constructed so that it is led out from the hole 19 toward the static elimination circumferential optical conductor 5 side.

(1) A slit-shaped entrance hole 29 is formed on the upper surface of the housing 12 adjacent to the electric appliance 6 to guide the laser beam emitted from the optical scanning unit 8 onto the photosensitive drum 11J line.

Further, the end side of the housing 12 located on the flow side of the developing device 2 is
It is sailed downward along the beam emission direction, is bent toward the developing unit 2 at a position close to the circumferential surface of the photoreceptor drum 1, and its free end side extends along a substantially tangential direction of the photoreceptor drum 1. Set up

A flat magnet body 20 made of an anisotropic magnet is fixed on the free end side facing the photoconductor drum 1, and the facing distance between the magnet body 20 and the photoconductor drum 1 is set. , is set so that it is about 0.5 to 2 ff1m at the closest position.

Note that the magnet body 20 does not necessarily have to be formed into a flat plate shape, and may be formed into a curved shape concentrically with the photoreceptor tram 1.

Incidentally, the upper end portions of the housing 12 on both left and right sides are provided with protrusions 23 that can be fitted into guide portions 21 and 22 attached to the support wall 7.
and four portions 24 are formed, and the unit body 4 is configured to be movable along the guide portions 21 and 22 in the axial direction of the photosensitive drum, thereby facilitating replacement and positioning of the unit body 4.

Further, the guide portion 21 on the developing device side is connected to the unit body 4 and the support wall 7.
It also functions as a door closing plate that integrally connects the magnet body 2.
The airflow is introduced into the unit body 4 only by the facing distance between the unit body 4 and the photosensitive drum 1.

On the other hand, a support wall 7 located on the rear side of the unit body 4 is integrally fixed to the body, and an ozone removal filter 25 is disposed at a position behind the static elimination lamp 17.

Further, a fan 26 is attached to the wall surface of the body on the optical scanning unit 8 side behind the ozone removal filter 25.

Next, the operation of this embodiment will be explained.

+iii When the fan 2B rotates, its suction force causes the scattered toner generated from the developing device 2 and its vicinity to be contaminated with I'7.
'The magnetic I/N is exposed to the photoreceptor along with the airflow).
After being attracted by the magnet 201 when passing through a position facing the ram 1, only the airflow is sucked into the unit body 4.

A part of the airflow sucked into the unit body 4 is...
;;7 After passing through the grid portion 6a and the discharge wire 0b in the electric appliance 6 and cleaning them, the discharged air is exhausted to the outside of the unit 71' through the exhaust hole 18.

Further, other air currents are similarly exhausted to the outside of the unit body 4 through the JJI pores 18 while passing through the light guides 5J,',l.

- Since the square static elimination lamp 17 is disposed facing the exhaust hole 18, it is depleted by clean air immediately after being discharged from the υ1 pore 18, so that a clean state can always be maintained.

The exhaust air after passing through the exhaust pump 17 passes through an ozone filter 25 and is extracted from the apparatus by a fan 2G.

Now, the magnet body 16 disposed on the end side of the housing 12 on the side of the cleaning device 9 is connected to the cleaning blade 13.
It is possible to capture more fallen toner and actively capture scattered toner to the outside.

That is, a part of the residual toner scraped off by the cleaning blade 13 enters the space between the magnet 16 and the photoreceptor drum 1, but is attracted by the magnet IG, and the stone body 1a is attached to the photoreceptor drum. Since the internal angle α formed by the tangents Vj and B-8 of 1 is set in the range of 20 to 30 degrees, the toner spikes do not fall downward, and the toner spikes do not fall between the magnet 16 and the photoreceptor drum 1. While forming, the toner slides along the rotation of the photosensitive drum 1, slides down into the toner storage section 14 along the kite 31, and forms a base that is collected in the toner container via the conveyance screen 5. .

"Effects of the Invention" As described above, according to the present invention, it is possible to actively prevent toner from adhering to the charger, static eliminator, or imaging optical system, etc., where toner adhesion poses a particular problem in image formation. (In addition, even if toner or dust accidentally lands on the various devices, it can be removed.) As a result, image clarity may be reduced, instability may occur, and maintenance may become complicated due to toner adhesion. It has various effects such as being able to avoid it.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the main structure of a laser printer according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing the arrangement of a second magnet body disposed on the cleaning blade side. Patent applicant: Kyocera Corporation −. 2"' Agent: Patent attorney Takahashi Hass',

Claims (1)

[Scope of Claims] 1) In an apparatus that performs image formation by an electrophotographic process using magnetic toner, an air current passes through a surrounding space from the downstream side of a cleaning member to the upstream side of a developing device along the rotational direction of an image carrier. 2) A second image forming apparatus that is arranged downstream of the cleaning member and facing the image carrier. An image forming apparatus according to claim 1, in which a magnet body is arranged.