JP2003315718A - Optical writing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital optical writing device which can prevent a dustproof glass from being left unmounted in order to normally operate a dustproof mechanism in an optical unit. <P>SOLUTION: In the optical writing device, the dustproof glass 10 is arranged in a manner such that it can be removed from a position in the optical path of a laser beam from an optical unit 9 to a photoreceptor drum 7 being an image carrier, the mounting of the dustproof glass 10 is detected by blocking the optical path of light to a synchronous detection sensor 8 by a shutter 13 when the dustproof glass 10 is removed. This optical writing device can prevent the dustproof glass from being left unmounted by simple constitution and control without arranging any special device. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital type optical writing apparatus, in order to normally operate the dustproof mechanism in the optical unit, without installing a special device, forgetting to attach the dustproof glass with a simple structure and control. The present invention relates to an optical writing device capable of preventing the above.

[0002]

2. Description of the Related Art Optical writing devices such as printers, copiers, and facsimiles often use an electrophotographic system. The general structure of the electrophotographic system is to uniformly charge light from optical means. Exposed on the photosensitive drum to form an electrostatic latent image,
This is adhered to toner to form a toner image, and the toner image is transferred and fixed on a transfer paper to fix the image.

In such an optical writing device, when the optical elements such as lenses and mirrors are contaminated by scattered toner in the machine, dust in the air, and the like, unevenness such as white stripes occurs on the formed image. Since the image quality remarkably deteriorates, the optical unit has a closed structure so that the optical elements are not contaminated, and is formed separately from the image forming unit having a photoconductor or the like. However,
Since the imaging light flux (laser light) from the optical unit must be introduced into the image forming unit, the optical unit and the image forming unit are connected by an optical path, and the laser light is transmitted to this optical path by using transparent dust-proof glass. It is transparent. Therefore, the laser light can pass from the optical unit to the image forming unit, but the scattered toner, dust in the air, etc. generated by the image forming operation cannot enter the optical unit.

In this case, since the surface of the dustproof glass on the side of the image forming unit is gradually soiled by the scattered toner in the image forming unit, it is necessary to periodically remove and clean the dustproof glass. However, if you remove the dust-proof glass and clean it, you may forget to mount it and then perform the image forming operation.In that case, scattered toner from the image forming unit may enter the optical unit and Was supposed to be badly soiled.

As a solution to this problem,
"Optical writing device" described in Japanese Patent Laid-Open No. 10-58750
However, the present invention relates to an optical writing device,
Dustproof glass is provided so that it can be retracted from the position where it blocks the optical path,
A shutter is provided to close the dust-proof glass when the dust-proof glass is retracted from the light path, and prevents the dust-proof glass from being forgotten to be attached. Specifically, an optical sensor is provided outside the image range of the image forming unit, and when the optical sensor does not detect light, the optical writing device is not operated or the light source side is outside the image range inside the optical unit. By providing the mirror and providing the synchronization detection sensor at the position where the reflected light from the light source side mirror is incident, the above-mentioned effect is obtained.

[0006]

However, in the former case, an optical sensor must be additionally provided, and this optical sensor is liable to be contaminated by scattered toner or the like in the image forming unit. Also, in the latter, since a synchronous detection sensor that measures the timing of writing is used, no special sensor is required, but when the dustproof glass is forgotten to be attached, the synchronous detection sensor detects light by entering twice. Therefore, control is needed for that, and
Since the shutter is movable, there is a problem that it is difficult to secure the angle accuracy with respect to the light flux of the mirror on the shutter.

Therefore, the present invention has been made in view of the above problems, and it is possible to prevent forgetting to attach the dustproof glass in the optical unit with a simple structure and control without providing a special device or control mechanism. An object is to provide an optical writing device.

[0008]

The optical writing apparatus according to the present invention comprises:
Video signal generating means for generating image data, laser beam generating means for generating a laser beam modulated by the video signal, deflecting means for deflecting and scanning the laser beam in the longitudinal direction of the image carrier are deflected. An image forming unit for focusing a laser beam on the image carrier to a predetermined diameter, an optical sensor for writing timing outside a range of a light beam required for image formation, and a housing member for holding these. An optical writing device having a dustproof glass detachable from the housing member in a laser beam optical path, comprising a shutter for blocking an optical path entering the optical sensor when the dustproof glass is removed. Is.

With such a structure, it is possible to prevent forgetting to attach the dustproof glass with a simple structure and control without providing a special device. In the present invention, the dustproof glass is a transparent one that does not block the optical path of the laser because the laser for writing from the optical unit to the image forming unit passes through it. Further, the shutter does not block the optical path through which light enters the optical sensor when the dust-proof glass is attached to the housing, and does not matter as long as it blocks the optical path when the dust-proof glass is removed. . further,
The optical sensor provided outside the image range of the image forming unit is a synchronous detection sensor for timing writing,
This is also used as a sensor for detecting whether or not the dustproof glass is attached. When the shutter blocks the optical path to the optical sensor, the optical sensor stops detecting light and detects that the dustproof glass is not attached.

Here, the shutter may be pressed against the dustproof glass by the spring means, and when the dustproof glass is removed, the shutter is moved by the spring means to close the optical path. With such a structure, if the dustproof glass is attached, the shutter is pressed against the dustproof glass and does not block the optical path, but when the dustproof glass is removed, the spring means works to move the shutter to move the optical path. Since the dustproof glass is closed, the act of removing the dustproof glass automatically closes the optical path, and it is possible to reliably know whether or not the dustproof glass is attached.

If the optical sensor does not detect light, the optical writing device may not be operated and an error may be notified to the user. If you do this,
When the dustproof glass is removed, the optical writing device itself does not operate, and it is announced that there is an error to that effect, so that it can be immediately recognized as an error due to the dustproof glass.

Further, it is possible to have a mechanical cover which can be opened and closed to cover the dustproof glass, and which is provided with a control mechanism for causing the optical writing device to perform an initialization operation when the mechanical cover is closed. It is also possible to adopt a configuration in which the error recognition and error notification of the optical sensor are performed during the initialization operation. With these, it is possible to immediately prepare for the operation of the optical writing device after the maintenance work is completed.
Further, it is possible to recognize an error caused by not mounting the dustproof glass.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical writing device of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a conventional optical writing device, and FIG. 2 is a diagram showing an example of the optical writing device of the present invention. Since the basic configurations in FIGS. 1 and 2 are common, the configurations of the optical writing devices in FIGS. 1 and 2 will be described below in comparison.

The beam emitted from the LD unit 1 is
The collimator lens 2 and the cylindrical lens 3 are focused so as to form an image on the reflection surface of the polygon scanner 4, and are deflected by the polygon scanner 4 at a constant angular velocity in the main scanning direction. The beam reflected by the polygon scanner 4 is fθ
The lens 5 corrects the surface of the photosensitive drum 7 so that the surface is deflected at a constant speed in the main scanning direction. Then, in order to detect the cue of the beam and the scanning speed (time), the synchronization detection sensor 8 is provided outside the image area in the main scanning direction.

In the optical writing device, the optical unit 9 has a hermetically sealed structure so as to prevent dirt on the optical elements such as lenses and mirrors due to scattered toner in the machine, dust and dirt in the air, and the like. The image forming unit is formed separately. However, the imaging light flux (laser light) from the optical unit 9 must be introduced into the image forming unit, and the optical unit 9 and the image forming unit are connected by an optical path. Then, this optical path is sealed with a transparent dustproof glass 10 so that scattered toner, dust and the like from the image forming unit do not enter the optical unit 9.

However, since the surface of the dustproof glass 10 is gradually soiled by scattered toner and the like in the image forming unit, it is necessary to periodically remove and clean the dustproof glass 10. Therefore, the dustproof glass 10 can be removed from the optical unit 9 by inserting and removing it in the longitudinal direction of the dustproof glass 10.

In the conventional optical writing device, if the dust-proof glass 10 is removed and cleaned, and then the image forming operation is performed without forgetting to mount it again, the scattered toner of the image forming unit enters the optical unit 9. And the optical elements are badly soiled,
In the present invention, control is provided so that an error occurs when the synchronization detection sensor 8 does not detect light, and the shutter mechanism 13 that blocks the light flux 14 entering the synchronization detection sensor 8 is provided. If the synchronization detection sensor 8 does not detect light, the optical writing device interrupts the image forming operation,
It is possible to immediately know that the dustproof glass 10 has not been attached.

Next, the operation of the shutter mechanism 13 will be described with reference to FIG. FIG. 3 is a diagram showing the operation of the shutter 13 from the left side of the front view of FIG. Figure 3
(A) is a diagram when the dustproof glass 10 is mounted, and at this time, the optical unit 9 is sealed, and the shutter 13 is movable in the longitudinal direction of the dustproof glass 10. It is pressed against the dustproof glass 10 by the spring means. Therefore, the synchronization detection sensor 8
The optical writing device operates normally without blocking the light flux 14 entering the optical writing device. Then, when the dustproof glass 10 is removed from the optical unit 9, the shutter 13 automatically moves in the direction of the arrow by the extension force of the spring, as shown in FIG. 3B. As a result, the projection of the shutter 13 blocks the light flux 14 entering the synchronization detection sensor 8. Even if an attempt is made to operate the optical writing device in this state, the optical writing device does not operate because the dustproof glass is not attached, and the user is notified of the error.

Next, the timing of error detection will be described with reference to FIG. FIG. 4 is a flowchart briefly explaining the error detection timing. In FIG. 4, after the polygon scanner 4 is started with the mechanical cover closed, the LD unit 1 is turned on to emit a beam and the polygon scanner 4 deflects the light beam. If the synchronization detection sensor 8 does not detect light for a predetermined time (for example, t seconds) after the light flux is deflected, the image forming operation is interrupted and an error is displayed on the machine operation panel. Here, the time during which the synchronization detection sensor 8 does not detect light can be set arbitrarily, and the error detection is controlled to be performed during initialization immediately after the cover is closed.

[0020]

As described above, according to the present invention, the optical writing device has the dustproof glass which can be detached from the housing member, and blocks the light path entering the synchronization detection sensor when the dustproof glass is removed. It is characterized in that a shutter is provided. This makes it possible to detect whether or not the dustproof glass is attached by using the synchronization detection sensor that has been used in the past, so you can forget to attach the dustproof glass with a simple configuration and control without installing a special device. It can be prevented. Therefore, if the dust-proof glass is not attached, the toner, dust, paper dust, etc. generated during the image forming operation will enter the inside of the optical unit. It is possible to prevent the work from being performed, and it is possible to prevent the optical elements inside the optical unit from becoming dirty.

Here, the shutter is brought into pressure contact with the dustproof glass by the spring means, and when the dustproof glass is removed, the shutter is moved by the spring means to block the optical path entering the synchronization detection sensor, whereby the shutter automatically moves. Since it is possible to detect that the dustproof glass is not attached due to the shutter, it is possible to reliably prevent forgetting to attach the dustproof glass. If the optical sensor does not detect light, the optical writing device is not operated and an error is notified to the user, so that it is possible to prevent work without attaching the dustproof glass. further,
If the optical sensor error recognition and error notification are performed during initialization immediately after the machine cover is closed, it means that the dust-proof glass is not attached immediately after the maintenance work is completed, so the unattached state is the minimum required. Can be on time. As a result, it is possible to minimize the entry of dust, dust, etc. into the optical unit.

[Brief description of drawings]

FIG. 1 is a schematic view of an optical unit and an image forming unit in a conventional optical writing device, (a) is a plan view and (b) is a front view.

2A and 2B are schematic views of an optical unit and an image forming unit in the optical writing device of the present invention, FIG. 2A is a plan view, and FIG. 2B is a front view.

FIG. 3 is a diagram showing the operation of the shutter of the optical writing device according to the present invention. FIG.
(B) shows the case where the dustproof glass is removed.

FIG. 4 is a flowchart of an error detection process of the optical writing device according to the present invention.

[Explanation of symbols]

1 LD unit 2 Collimating lens 3 Cylindrical lens 4 polygon scanner 5 fθ lens 6 toroidal lens 7 Photosensitive drum 8 synchronization detection sensor 9 Optical unit 10 dust-proof glass 11 folding mirror 12 Folding mirror for synchronization detection 13 Shutter 14 Sync detection sensor Incident light flux

Claims (5)

[Claims] 1. A video signal generating means for generating image data, a laser beam generating means for generating a laser beam modulated by the video signal, and a deflecting means for deflecting and scanning the laser beam in a longitudinal direction of an image carrier. An image forming means for focusing the deflected laser beam on the image carrier to a predetermined diameter, an optical sensor for taking a writing timing out of the range of a light beam necessary for image formation, and for holding these. Of the housing member and a dustproof glass removable from the housing member in the optical path of the laser beam, the shutter having a shutter for blocking the light path entering the optical sensor when the dustproof glass is removed. An optical writing device characterized by: 2. The shutter is pressed against the dust-proof glass by spring means, and is moved by the spring means when the dust-proof glass is removed so as to close an optical path entering the optical sensor. The optical writing device according to claim 1, wherein the optical writing device is an optical writing device. 3. The optical writing device according to claim 1, wherein when the optical sensor does not detect light, the optical writing device is not operated and an error is notified to a user. 4. A mechanical cover that can be opened and closed to cover the dustproof glass, and the optical writing device performs an initialization operation when the mechanical cover is closed. An optical writing device according to item. 5. The optical writing device according to claim 4, wherein an error is recognized by the optical sensor during the initialization operation, and the error is notified to a user.