JP2003094723A - Writing optical system unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a writing optical system unit in which the optical path of laser light can be adjusted readily and automatically without relying upon manual work, e.g. untightening a screw, and without requiring a troublesome work, e.g. removing the contact glass of a scanner. SOLUTION: In the writing optical system unit comprising a laser light source and irradiating the surface of a photosensitive drum with light from the light source through a reflector, a unit frame incorporating the laser light source and the reflector is held in an imaging apparatus rotatably in a plane parallel with the axial direction of the photosensitive drum and rotation of the frame unit is controlled by means a motor driven cam, and a resilient member for urging the unit frame against the cam face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital copying machine,
The present invention relates to a writing optical system unit (LSU) used in an image forming apparatus such as a printer or a facsimile.

[0002]

2. Description of the Related Art In the above-mentioned image forming apparatus utilizing electrophotography, the surface of a photosensitive drum is uniformly charged, and the charged surface of the photosensitive drum is irradiated with light based on certain image information. Thereby forming an electrostatic latent image (charge image), developing the electrostatic latent image using a developer containing toner charged to a predetermined polarity, and transferring the obtained toner image to a transfer sheet such as paper or OHP film. By transferring to the surface and thermally fixing the transferred toner image with a heat roller (fixing roller),
Image formation is performed. In such an image forming process, formation of an electrostatic latent image by irradiation of light on the surface of a charged photosensitive drum, that is, writing of image information is performed by so-called LS.
It is done by a writing unit called U.

The LSU is provided with a laser light source such as a laser diode, and the laser light is passed through an optical system such as a polygon mirror based on image information from an information processing device such as a scanner (reading optical system) or a computer. The structure is such that the surface of the photosensitive drum is irradiated. As such an LSU, a type in which laser light is reflected by a reflection mirror and is incident on the surface of the photosensitive drum is known.

By the way, in the LSU, it is necessary to irradiate the surface of the photosensitive drum with the laser beam so that the beam width thereof is parallel to the axial direction of the photosensitive drum. This is because, when the light beam width is inclined and irradiated, a transfer image is obliquely formed on a transfer sheet such as paper. Therefore, in the LSU of the type using the reflection mirror as described above, the unit frame is rotatably held in a plane parallel to the axial direction of the photosensitive drum in the image forming apparatus, and is formed on the unit frame. By screwing a screw etc. through the slotted hole,
The unit frame is fixed in the image forming apparatus. That is, by loosening the screw and rotating the unit frame, the optical path (irradiation line inclination) of the laser light emitted by reflection on the reflection mirror is adjusted.

[0005]

However, when the LSU is attached to the image forming apparatus by the above means,
The adjustment of the optical path of the laser light has to be performed manually, which makes maintenance extremely troublesome. Further, in a digital copying machine or the like, since the scanner is mounted on the upper part of the LSU, in order to loosen the screw fixing the unit frame of the LSU, the contact glass of the scanner has to be removed, which is extremely troublesome. It requires work. Moreover, when the contact glass is removed, dust and the like enter the inside of the scanner, which causes image defects such as black streaks.

Therefore, an object of the present invention is to automatically and easily adjust the optical path of a laser beam without resorting to manual work such as loosening a screw, and without performing a troublesome work such as removing a contact glass of a scanner. The present invention is to provide a writing optical system unit (LSU) capable of performing the above.

[0007]

According to the present invention, there is provided a writing optical system unit which comprises a laser light source and irradiates the light from the light source onto the surface of the photosensitive drum through the reflection mirror, wherein the laser light source and the reflection mirror are provided. The unit frame containing the is rotatably held in the image forming apparatus in a plane parallel to the axial direction of the photoconductor drum, and the rotation of the unit frame includes a cam rotated by a motor drive. A writing optical system unit in an image forming apparatus is provided, which is controlled by an elastic member that biases the unit frame to a cam surface.

That is, in the writing optical system unit (hereinafter referred to as LSU) of the present invention, the unit frame is rotated in a plane parallel to the axial direction of the photosensitive drum by rotating the cam by driving the motor. Can be made. Therefore, the optical path of the laser beam can be easily adjusted automatically by controlling the motor, and it is not necessary to perform manual work such as loosening the screw. Further, when this LSU is applied to a digital copying machine, it is not necessary to remove the contact glass of the scanner for adjusting the optical path.

In the present invention, it is preferable to provide a pair of sensors for detecting a potential decrease on the surface of the photosensitive drum in the vicinity of the axial end surface of the photosensitive drum mounted in the image forming apparatus. . That is, the surface of the photosensitive drum is irradiated with laser light by using LSU, the potential of the surface of the photosensitive drum is detected by the pair of sensors, and the cam is rotated by the motor based on the detection signal to rotate the cam of the unit frame. By adjusting the position, it is possible to adjust the optical path of the laser light so that the laser light from the laser light source via the reflection mirror is irradiated in parallel to the axial direction of the photosensitive drum.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A case where the LSU of the present invention is applied to a digital copying machine will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view showing the entire structure of a digital copying machine equipped with the LSU of the present invention, FIG. 2 is a schematic top view showing the LSU of the present invention, and FIG. 3 is a main part of the present invention. FIG. 4 is an enlarged view of the cam mechanism, which is FIG.
2 is a perspective view showing the arrangement of potential sensors provided in the digital copying machine of FIG.

In FIG. 1, which schematically shows the overall structure of a digital copying machine, which is a typical example of an electrophotographic image forming apparatus, a photosensitive drum 1 is rotatably mounted in the copying machine. Around the drum 1, a main charging device 2, a developing device 3, a transfer and paper separating device 4 and a cleaning device 5 are provided along the rotation direction thereof. Further, although not shown, a static eliminator is provided between the transfer / paper separation device 4 and the cleaning device 5 or between the cleaning device 5 and the main charging device 2. That is, the surface of the photosensitive drum 1 is uniformly charged with a predetermined polarity by the main charging device 2, and then an electrostatic image is formed by light irradiation (the optical path is indicated by L) based on predetermined image information. . The electrostatic latent image formed on the surface of the photoconductor is developed by the developing device 3, whereby a toner image corresponding to image information is formed. The toner image is transferred onto a transfer sheet (not shown) such as paper that has been conveyed between the photosensitive drum and the transfer / paper separation device 4, and the transfer toner image is formed on the surface of the transfer sheet. Is supplied to a fixing device (not shown), the toner image is fixed on the transfer sheet by heat, pressure, etc., and the transfer sheet on which the toner image is fixed is discharged to the outside of the device. After the toner image is transferred, the cleaning device 5 cleans the residual toner on the surface of the photosensitive drum 1, and the charge is further removed, thereby completing one cycle of image formation.

On the other hand, a scanner 10 for obtaining the above-described image information is provided above, and below the scanner (reading optical system) 10, the surface of the photosensitive drum 1 is irradiated with light based on the image information. LSU (writing optical system unit) 12 is arranged for this purpose. Although not shown, an openable and closable cover is attached to the top of the scanner 10, and an automatic document feeder is provided on this cover.

An outline of the scanner 10 will be described. A contact glass for mounting a document is attached to the upper surface of the scanner 10, and an optical source such as a light source, a mirror, a lens, etc., provided under the contact glass so as to be scannable. The system and CCD elements are housed. That is, the light source irradiates an original document placed on the contact glass or passing through the contact glass, and the reflected light from the original document is received by the CCD element through an optical system such as a lens, and image information of the original document is obtained. It is structured so that it can be read.

Based on the image information read by the CCD device as described above, the surface of the photosensitive drum 1 is irradiated with the laser light by the LSU 12, and the image is formed according to the above-mentioned image process. This LSU1
2 includes a laser light source 12a such as a laser diode, a polygon mirror 12b, and a reflection mirror 12c,
Laser light based on the above image information is applied to the surface of the photosensitive drum 1 via the reflection mirror 12c. In Figure 1,
The optical path of such laser light is indicated by L.

When a laser beam is applied to the surface of the photosensitive drum 1, that is, writing is performed by using the LSU 12 as described above, the inclination of the beam of the laser beam is parallel to the axial direction of the photosensitive drum. First, the surface of the drum 1 must be illuminated. This is because, as already described, when the light rays are obliquely applied, a transfer image is obliquely formed on a transfer sheet such as paper. In the present invention, the means described below are adopted in order to easily adjust the optical path of such a laser beam.

In FIG. 2 showing the upper surface of the LSU 12 described above, the unit frame has a box shape as a whole, and one peripheral edge portion (upper peripheral edge portion in FIG. 2) thereof.
Are rotatably held inside the device by these screws or pins 22. Further, elongated holes 23, 23 are provided along the circumference with the screw or pin 22 as a fulcrum,
By inserting the anti-floating pin through this long hole, LSU1
Reference numeral 2 is held by the device body mounting plate. That is, the LSU 12 is rotatable in the plane parallel to the axial direction of the photoconductor drum 1 with the screw or pin 22 as a fulcrum.

In the present invention, the cam 25 provided on the apparatus body mounting plate is in contact with the corner portion of the unit frame, and the elastic member 27 is provided between the other corner portion and the apparatus side plate 30. It is provided. That is, the elastic member 27
Thus, the LSU 12 is biased to come into contact with the cam surface of the cam 25. In addition, referring to FIG. 3 showing an enlarged view of a cam mechanism that is a main part of the present invention, the cam 25 is a motor of the motor M provided on the apparatus body mounting plate via a drive transmission member 26 such as a gear. It is provided so as to rotate when driven.

As can be understood from FIG. 2 described above, according to the present invention, the cam 25 is rotated by driving the motor M, and the unit frame (LSU 12) is rotated about the screws or the pins 22 as a fulcrum. Therefore, by adjusting the drive rotation of the motor M, it becomes possible to rotate the LSU 12 and adjust the optical path of the laser light.

Further, in the present invention, the optical path of the laser beam can be easily adjusted by rotating the LSU 12 in the plane parallel to the axial direction of the drum 1 as described above. For such optical path adjustment, as shown in FIGS. 1 and 4, a pair of potential sensors 30, 30 are arranged near the surface of the photosensitive drum 1. That is, as is apparent from FIG. 4, this potential sensor 3
0 and 30 are arranged at both ends of the photoconductor drum 1 so as to be parallel to the axis 1a thereof. Using such potential sensors 30 and 30, laser light is emitted from the LSU 12 while rotating the photoconductor drum 1 to detect a potential drop at both ends of the surface of the photoconductor drum 1, and the ray width of the optical path L is the axis line. A check is made to see if it is parallel to 1a. Therefore, in this inspection, when the light beam width 1a is inclined with respect to the axis 1a, the motor M and the cam 2 are driven.
The optical path can be adjusted by rotating the LSU 12 with the rotation of 5.

In the example of FIG. 2 described above, the unit frame of the LSU 12 is rotatably held, and the screws or pins 22 serving as the fulcrum of rotation are arranged at the peripheral portion on one side of the unit frame, and The cam 25 and the elastic member 27 have a structure arranged near both corners of the peripheral edge on the other side of the unit frame, but the present invention is not limited to such a structure, and the cam 25 Rotation of the LSU
These members can be arranged at arbitrary positions as long as 12 can rotate smoothly around the screws or pins 22 as fulcrums.

Further, in FIGS. 1 to 4, the LSU of the present invention is used.
Although an example in which 12 is applied to a digital copying machine is shown, it is obvious to those skilled in the art that such an LSU 12 can be applied to an image forming apparatus other than the digital copying machine, such as a facsimile or a printer. Ah

[0022]

The writing optical system unit (LS of the present invention
According to U), the optical path adjustment of the laser light by rotating the unit (adjusting the optical path so as to be parallel to the axial direction of the photoconductor drum) does not depend on an operation such as manually rotating a screw, For example, it can be easily performed by automatic operation using a motor drive switch or the like provided on the operation panel of the image forming apparatus. Therefore, the optical path adjustment work accompanying the work such as LSU replacement becomes extremely easy, which is extremely advantageous in maintenance and the like. Further, when this LSU is used in a digital copying machine, a facsimile, etc., the troublesome work of removing the contact glass of the scanner at the time of the optical path adjustment work is unnecessary, and the image defect due to the intrusion of dust etc. due to the removal of the contact glass can be avoided. Trouble can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall structure of a digital copying machine equipped with an LSU of the present invention.

FIG. 2 is a schematic bottom view showing an LSU of the present invention.

FIG. 3 is an enlarged view showing a cam mechanism which is a main part of the present invention.

FIG. 4 is a perspective view showing the arrangement of potential sensors provided in the digital copying machine of FIG.

[Explanation of symbols]

1: photoconductor drum 12: LSU 22: Screw or pin 25: Cam 27: Elastic member 30: Potential sensor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshihide Hozono             Kyocera 1-22-28 Tamatsukuri, Chuo-ku, Osaka-shi             Within Mita Co., Ltd. (72) Inventor Atsushi Ishizaki             Kyocera 1-22-28 Tamatsukuri, Chuo-ku, Osaka-shi             Within Mita Co., Ltd. F-term (reference) 2C362 AA43 AA45 AA48 BA82 BA90                       DA04                 2H045 DA01 DA04 DA41                 2H076 AB05 AB18 AB73 EA15 EA24                 5C051 AA02 CA07 DB02 DB22 DB24                       DB30 DC04 DC07 DE09                 5C072 AA03 BA02 HA02 HA13 HB08                       XA01 XA05

Claims (2)

[Claims] 1. A writing optical system unit comprising a laser light source, and irradiating light from the light source onto a surface of a photoconductor drum via a reflection mirror, wherein a unit frame containing the laser light source and the reflection mirror is a photoconductor drum. Is held in the image forming apparatus so as to be rotatable in a plane parallel to the axial direction of the unit frame, and the rotation of the unit frame is driven by a motor, and the unit frame is biased to the cam surface. And a writing optical system unit in an image forming apparatus, the writing optical system unit being controlled by the elastic member. 2. A pair of sensors for detecting the potential of the surface of the photosensitive drum is provided near the surface of both ends of the photosensitive drum mounted in the image forming apparatus in the axial direction,
The position of the unit frame is such that the rotation of the cam based on the detection signal of the sensor irradiates the laser light from the laser light source so that the beam width thereof is parallel to the axial direction of the photosensitive drum. The writing optical system unit according to claim 1, wherein adjustment is performed.