JPH11194683A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always form a stable image and to improve quality by providing an air curtain for preventing the mutual mixture of air on the side of a process cartridge and that on the side of a fixing device on a carrying path on which recording material is carried. SOLUTION: A duct 3 is allowed to pass in a recording material width direction to a side (side of a driving side plate 6) opposite to a fan 5 under an optical box 2, and it is allowed to pass to the upper surface of the box 2 on the side of the plate 6. By boring plural slots on a part of the base of the duct 3, a part of the air taken in from the fan 5 falls down from the slot so as to form the air curtain, and heat or vapor outgoing from the fixing device 4 is prevented from flowing to the side of the cartridge. As for the shape of the slot at a part of the base of the duct 3; the slot is formed so that its side of the fan 5 where wind pressure is high may be thin and its width may be larger as it goes away from the fan 5, whereby the flow of the air outgoing from the slot is kept constant in width, right and left, as shown by an arrow. Furthermore, by making the slot in mesh shape, dust is prevented from advancing into the inner part of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a recording material, such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art FIG. 6 shows a laser printer equipped with a process cartridge as a specific example of a conventional image forming apparatus.

FIG. 6 is a sectional view of a laser printer. The laser printer mounts a process cartridge 101, forms an image by an electrophotographic method, and records the image on a recording material.

In the process cartridge 101, a photosensitive drum 102 serving as an image carrier is rotatably provided in a frame, and charging means for uniformly charging the surface of the photosensitive drum 102 around the photosensitive drum 102, Charged photosensitive drum 10
Developing means for developing a latent image formed by irradiating a light image corresponding to the image information with a developer (hereinafter, referred to as toner) to visualize the toner image as a toner image, and recording the toner image A cleaning unit is provided for removing toner remaining on the surface of the photosensitive drum 102 after transfer to the material P.

These are integrated into a cartridge by a frame.

Incidentally, the laser printer has a mounting means for mounting the process cartridge 101 in the apparatus main body.

On the other hand, an optical system 103 for irradiating the photosensitive drum 102 with a light image corresponding to image information is provided at an upper portion in the apparatus main body.

The recording material P stored in the paper feed cassette 104 is fed by a paper feed roller 105 and a separation claw 10 operated by a print signal from a host computer (not shown).
6, the sheets are separated and fed one by one.

The recording material P is conveyed after being turned upside down through a paper feed reversing section composed of a conveying roller 107, a first roller 108, a second roller 109, and a third roller 110, and is rearward in the apparatus main body (FIG. 6 left).

The recording material P is transferred to a transfer guide 111.
And is conveyed to a pressure nip between the photosensitive drum 102 and the transfer roller 112.

On the other hand, image information from a host computer (not shown) is irradiated as an optical image from the optical system 103 onto the photosensitive drum 102 in the process cartridge 101 to form a latent image on the photosensitive drum 102 in accordance with the image information. The latent image is developed by toner and visualized.

The transfer material P is conveyed at a timing corresponding to the image information developed as a toner image, and is applied to the transfer roller 112 by applying a voltage having a polarity opposite to that of the toner image formed on the photosensitive drum 102 to a pressure contact. In the nip portion, the toner image on the photosensitive drum 102 is transferred to the recording material P.

Immediately after passing through the transfer section, the recording material P having received the transfer of the toner image passes right above a static elimination needle (not shown) and a static elimination needle holder 113 which guides the static elimination needle. Is conveyed to a fixing device 118 through a conveying path 115 provided in the fixing device 118, and the fixing film 1 of the fixing device 118 is
The toner image is fixed by passing through a pressure nip portion between the pressure roller 16 and the pressure roller 117.

The recording material P that has passed through the fixing device 118
Is again turned upside down through the rear part of the apparatus main body behind the fixing device 118, and is discharged onto a discharge tray 119 provided at the upper part of the apparatus main body by a discharge roller.

[0015]

In the prior art, the fixing device 1 is used.
The heat and water vapor of No. 18 reached the process cartridge 101 through the transport path 115, causing troubles such as image defects and toner adhesion.

Further, particularly when used in a high-temperature and high-humidity area, image defects are likely to occur.

Further, when a circuit is designed for high temperature and high humidity, there is a problem in terms of cost because a substrate for high temperature and high humidity is newly manufactured in the prior art.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image forming apparatus which always forms a stable image and has excellent quality. .

[0019]

According to the present invention, there is provided a process cartridge for transferring an image to a recording material, and a fixing device for fixing an unfixed image on the recording material. An image forming apparatus, wherein an air curtain is provided on a transport path for transporting a recording material from the process cartridge to the fixing device to prevent air from being mixed between the process cartridge and the fixing device. I do.

Therefore, it is possible to prevent heat and water vapor from the fixing device from flowing into the process cartridge, and to form a stable image.

A duct extending in the width direction of the recording material is provided, the duct is provided with a blowing means for blowing air, and the air curtain is provided with a plurality of slots in the width direction of the recording material.
Preferably, it is formed by air blown from the plurality of slots.

Thus, the air curtain can be formed by a part of the air taken into the duct.

An optical box for irradiating the image carrier with a light image corresponding to image information has through holes in upper and lower wall surfaces in part.
It is preferable that the duct connected to the through hole is provided below the optical box.

Thus, unnecessary space in the optical box can be effectively used.

[0025] It is preferable that the plurality of long holes are provided such that the long holes on the side of the blowing means are provided small, and the long holes are provided as the distance from the blowing means increases.

Thus, the blowing pressure of the air curtain can be made uniform in the width direction of the recording material, and a more uniform air curtain can be formed.

[0027] It is preferable that a partition plate for controlling a blowing direction of the air curtain is provided.

Thus, the air curtain can be formed in a predetermined direction.

It is preferable that the partition plate swings in conjunction with the attachment / detachment of the process cartridge.

Thus, even if process cartridges having different sizes are mounted, the air curtain can be formed in a predetermined direction.

It is preferable that a power supply sequence to the process cartridge is determined by a sensor for detecting the swing of the partition plate.

[0032]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) In FIGS. 1, 2 and 3, reference numeral 1 denotes a main body frame, and 2 denotes an optical element for irradiating a photosensitive drum 10 as an image carrier with a light image corresponding to image information. Box 3, a ventilation duct attached to the lower side of the optical box,
Reference numeral 4 denotes a fixing unit that applies temperature-controlled heat to the transferred recording material P, 5 denotes a fan as a blowing unit for taking in outside air into the main body, 6 denotes a driving side plate for fixing a driving gear,
7 is a cassette for storing the recording material before transfer, 8
Is an upper cover also serving as a paper discharge tray, 9 is a process cartridge for transferring image information to a recording material, 10 is a photosensitive drum for forming image information from the optical box 2 as a toner image, and 11 is an electronic component. It is an electrical board.

With such a configuration, the recording material stored in the cassette 7 is separated and fed one by one by a paper feed roller and a separation claw 106 operated by a print signal from a host computer.

The recording material is conveyed after being turned upside down and conveyed through a paper feed reversing section composed of a conveying roller, a first roller, a second roller, and a third roller, and is guided by a transfer guide and transferred to the photosensitive drum 10. It is conveyed to the pressure nip portion with the roller.

On the other hand, image information from a host computer (not shown) is radiated as an optical image from the optical box 2 to the photosensitive drum 10 in the process cartridge 9 so that the photosensitive drum 10
A latent image corresponding to the image information is formed, and the latent image is developed with toner and visualized.

The transfer material is conveyed at a timing corresponding to the image information developed as a toner image, and is applied to the transfer roller by applying a voltage having a polarity opposite to that of the toner image formed on the photosensitive drum 10 to the pressing nip portion. At this time, the toner image on the photosensitive drum 10 is transferred to the recording material.

Immediately after passing through the transfer section, the recording material to which the toner image has been transferred passes right above a static elimination needle (not shown) and a static elimination needle holder that guides the static elimination needle, and is provided on the electrical unit. Then, the toner image is conveyed to the fixing device 4 through the conveying path, and passes through the fixing nip portion of the fixing film and the pressure roller of the fixing device 4 to receive the fixation of the toner image.

Here, a fan 5 is provided below the optical box 2.
To the other side (drive side plate 6 side) in the width direction of the recording material
Then, on the drive side plate 6 side, the duct 3 is further passed to the upper surface of the optical box 2.

By making a plurality of long holes in a part of the bottom surface of the duct 3 (in the width direction of the recording material), a part of the air taken in from the fan 5 descends from the long holes to form an air curtain, and a fixing device is formed. The heat and water vapor coming out of 4 are prevented from flowing to the cartridge 9 side.

Also, as shown in FIG. 1 (a), the shape of a part of the oblong hole on the bottom surface of the duct 3 is made thinner on the side of the fan 5 where the wind pressure is high, and wider as the distance from the fan 5 increases. As shown by the arrow in FIG. 1B, the flow of air flowing out of the elongated hole is kept constant in the left-right width.

Further, by forming the elongated holes in a mesh shape, it is possible to prevent the air flowing in the duct from being reduced more than necessary, and to prevent dust from entering the inside of the device.

Incidentally, the plurality of long holes in a part of the bottom surface of the duct 3 (in the width direction of the recording material) may have a fixed long hole shape as shown in FIG. 2, but are not limited to these.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. FIG. 4 is a longitudinal sectional view of a laser beam printer which is an image forming apparatus according to the second embodiment.

Since the basic structure of the main body in this embodiment is the same as that of the first embodiment, in FIG. 4, the same elements as those shown in FIGS. In the following, description thereof will be omitted.
Reference numeral 12 denotes a partition plate that swings in conjunction with the attachment and detachment of the process cartridge 9.

The basic structure of the optical box 2 is the same as that of the first embodiment, but a spring-biased partition plate 12 is mounted around a long hole formed in the bottom surface (main scanning direction) of the duct. .

The partition plate 12 swings in conjunction with the mounting and dismounting of the process cartridge 9 and is lowered only when the process cartridge 9 is mounted. Therefore, the hand is not hurt by the partition plate 12 during the jam processing.

Further, the angle of the partition plate 12 changes depending on the type and size of the process cartridge 9 to be mounted, so that the wind can always be sent in the direction of the photosensitive drum. Wind can be sent around the drum. The temperature around the photosensitive drum can be reduced.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a longitudinal sectional view of a laser beam printer which is an image forming apparatus according to the third embodiment.

Since the basic configuration of the main body in this embodiment is the same as that of the first embodiment, in FIG. 5, the same elements as those shown in FIGS. In the following, description thereof will be omitted.

Reference numeral 13 denotes a sensor flag which rotates in conjunction with the partition plate 12, and reference numeral 14 denotes a photomicrosensor for switching the sequence.

The basic configuration of the optical box 2 is the same as that of the second embodiment, except that a sensor flag 13 linked to the partition plate 12 is attached, and a photomicrosensor 14 corresponding to the sensor flag 13 is installed.

The sensor flag 13 attached to the other end of the partition plate 12 rotates in accordance with the attachment / detachment of the process cartridge 9.

As in the second embodiment, a process cartridge 9 having a different shape from that of a general container and a shape of a container adjusted for a high-temperature and high-humidity environment, for example, is prepared. Partition plate 12
And the position of the sensor flag 13 is changed.

Only when the process cartridge 9 for high temperature and high humidity is inserted, the sensor flag 13 turns off the photomicrosensor 14, and a sequence for high temperature and high humidity on a circuit is set.

As described above, by detecting the difference between the movements of the sensor flag 13 and switching the sequence, it is not necessary to produce two types of substrates, and the cost can be reduced.
Even when environmental conditions change, stable image quality is always achieved.

[0057]

According to the present invention, an air curtain is provided on a conveyance path for conveying a recording material from a process cartridge to a fixing device to prevent air from being intermingled between the process cartridge and the fixing device. Heat and water vapor can be prevented from flowing into the process cartridge, and a stable image can be formed.

A duct extending in the width direction of the recording material is provided, the duct is provided with air blowing means for blowing air, a plurality of long holes are provided in the width direction of the recording material, and the air curtain is provided with air blown from the plurality of long holes. The air curtain can be formed by a part of the air taken into the duct.

An optical box for irradiating the image carrier with a light image corresponding to the image information has through holes in upper and lower wall surfaces in part.
By providing the duct connected to the through hole below the optical box, an unnecessary space of the optical box can be effectively used.

The plurality of elongated holes are provided with a small elongated hole on the side of the air blowing means, and provided with a large elongated hole farther from the air blowing means, so that the blowing pressure of the air curtain can be made uniform in the width direction of the recording material. And a more uniform air curtain can be formed.

The provision of the partition plate for controlling the air blowing direction of the air curtain allows the air curtain to be formed in a predetermined direction.

Since the partition plate swings in conjunction with the mounting and dismounting of the process cartridge, an air curtain can be formed in a predetermined direction even when process cartridges of different sizes are mounted.

By determining the power supply sequence to the process cartridge by the sensor for detecting the swing of the partition plate, it is not necessary to produce a substrate or the like for use in a high-temperature and high-humidity area, thereby reducing the cost. it can.

[Brief description of the drawings]

FIG. 1A is a partially cutaway perspective view showing an image forming apparatus according to a first embodiment of the present invention.
(B) is a cross-sectional view.

FIG. 2A is a partially cutaway perspective view showing the image forming apparatus according to the first embodiment of the present invention, and FIG.
(B) is a cross-sectional view.

FIG. 3 is a longitudinal sectional view showing the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing an image forming apparatus according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing an image forming apparatus according to a third embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing an image forming apparatus according to the related art.

[Explanation of symbols]

 Reference Signs List 1 frame 2 scanner optical box 3 duct 4 fixing device 5 fan 6 drive side plate 7 cassette 8 upper cover 9 cartridge 10 photosensitive drum 11 electrical board 12 partition plate 13 sensor flag 14 photo micro sensor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Susumu Ikuma 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shuji Nishitani 3- 30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the corporation

Claims (7)

[Claims] 1. A process cartridge for transferring an image to a recording material, a fixing device for fixing an unfixed image on the recording material,
An image forming apparatus comprising: an air curtain provided on a conveyance path for conveying a recording material from the process cartridge to the fixing device, for preventing air from being intermingled between the process cartridge and the fixing device. Characteristic image forming apparatus. 2. A duct extending in the width direction of the recording material is provided, the duct is provided with a blowing means for blowing air, and is provided with a plurality of slots in the width direction of the recording material. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed by air blown from a hole. 3. An optical box for irradiating the image carrier with a light image corresponding to image information has a through hole in a part of upper and lower wall surfaces, and the duct connected to the through hole is provided below the optical box. The image forming apparatus according to claim 2, wherein the image forming apparatus is provided. 4. The image forming apparatus according to claim 2, wherein the plurality of long holes are provided such that the long holes on the side of the blower are smaller and the longer holes are provided farther from the blower. apparatus. 5. The image forming apparatus according to claim 1, further comprising a partition plate for controlling a blowing direction of the air curtain. 6. The image forming apparatus according to claim 5, wherein the partition plate swings in conjunction with attachment and detachment of the process cartridge. 7. The image forming apparatus according to claim 6, wherein a power supply sequence to the process cartridge is determined by a sensor that detects the swing of the partition plate.