JPH0976554A - Optical scanning recorder - Google Patents

Abstract

(57) [Summary] [Object] In an optical scanning recording apparatus, image deterioration due to focal length variation of imaging optics, image deterioration due to deviation of laser beam irradiation position, occurrence of image deterioration due to reflected light, etc. Prevents and facilitates parts replacement and maintenance. [Structure] A plurality of imaging lenses 3 for imaging a laser beam
By adjusting the mounting member 49 of the first and second reflecting mirrors 35 and 36 that can be moved integrally with each other between 3 and 34, the variation in the focal length of the imaging lens is corrected and the laser beam having the required diameter is exposed. Images are formed on the body surface to prevent image deterioration. By adjusting a mounting member of the third reflecting mirror 37 capable of adjusting the irradiation of the laser beam at a predetermined position on the surface of the photoconductor 43, the occurrence of image deterioration due to the deviation of the irradiation position of the laser beam is prevented. Further, the lid 41 of the recording unit corresponding to the part 46 of the openable / closable bottom plate of the exposure optical system unit can be opened / closed to facilitate maintenance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning recording device used in copying machines, laser beam printers and the like.

[0002]

2. Description of the Related Art A copying machine and a laser beam printer are semiconductor lasers that generate a laser beam and shape the generated laser beam in order to scan and expose a charged photosensitive drum surface with a laser beam according to an image signal. The unit includes a unit, a rotation deflecting unit that scans the shaped laser beam, an image forming optical unit that forms an image on the surface of the photoconductor, and a synchronization detecting unit that sets the writing timing of the image signal. A semiconductor laser unit that generates this laser beam and shapes the generated laser beam, a rotation deflecting unit, and a latent image formed on the surface of the photosensitive drum that is uniformly charged through the image forming optical unit are used as normal toner. It is developed with a so-called powder substance and this toner image is transferred to paper, fixed in a fuser and finally printed out. At this time, writing of an image signal is started by detecting the laser beam by the synchronization detection means, and the laser beam is scanned and exposed on the surface of the photosensitive drum.

A conventional optical scanning recording device will be described below. 12, 13, 14, and 15 show the configuration of a conventional optical scanning recording apparatus, and FIG. 12 is a configuration diagram, FIG.
FIG. 3 is a front view of FIG. 12 showing an optical path of a laser beam applied to the surface of the photoconductor, FIG. 14 is an overall configuration of the copying machine, and FIG. 15 is a configuration of a semiconductor laser unit. FIG.
In 2 and 13, 81 is a semiconductor laser unit and 82
Is a polygon scanner, 83 is an fθ lens, 84 is a CY lens, 85 is a reflection mirror, 86 is a synchronization detection means, 87,
89 is a laser beam, 88 is a photoconductor, and in FIG.
Reference numeral 90 is a copying apparatus, 91 is an exposure optical system unit, 92 is an image forming mechanism, 93 is a recording unit, 94 in FIG. 15, 94 is a semiconductor laser, 95 is a collimator lens, 96 is an aperture, and 97 is a cylinder lens.

The operation of the optical scanning recording apparatus having the above structure will be described below. The laser beam emitted from the semiconductor laser 94 includes a collimator lens 95 and an aperture 9 provided in the semiconductor laser unit 81.
6, the laser beam parallel-shaped by the cylinder lens 97 and parallel-shaped by the polygon scanner 82 is deflected and scanned, and the laser beam in the image area is fθ lens 83, CY.
The beam diameter is narrowed by the lens 84, fθ scanning characteristics and surface tilt correction are given, reflected by the reflection mirror 85, and image-formed on the surface of the photoconductor 88. On the other hand, when the laser beam 87 is incident on the synchronization detection means 86, the writing timing of the image signal is set. In this way, the recording unit 9 configured to irradiate the laser beam
The laser beam of No. 3 is image-scanned on the photoconductor 88 in the image forming mechanism 92.

[0005]

However, in the above-described structure, a predetermined beam diameter is formed on the surface of the photosensitive member by the image forming optics of the fθ lens and the CY lens.
If there is variation in the focal length of the imaging optics of the lens and the CY lens, the laser beam is imaged at the focal point, that is, at a position other than the surface of the photoconductor, and as a result, the diameter of the laser beam becomes large on the surface of the photoconductor and the image of the image becomes large. It has a problem that deterioration occurs.

For example, as the imaging optics, an fθ lens, C
In the one using a Y lens and one reflection mirror (Japanese Patent Laid-Open No. 3-247541), an imaging optical lens and a mirror are fixed, and a laser beam is imaged on the surface of a photoconductor due to the presence of variations in focal length. Is a method of adjusting the focal length variation of the imaging lens with a collimator lens, that is, the collimator lens of the semiconductor laser unit is moved and adjusted along the optical axis according to the focal length variation, and a laser beam is formed on the surface of the photoconductor. Although there is a method of forming an image, this method adjusts according to the variation in the focal length of the imaging lens, so that the imaging lens and the semiconductor laser unit have a one-to-one correspondence.
Will be required. If the semiconductor laser fails, it becomes difficult to replace only the semiconductor laser unit due to the relationship between the semiconductor laser unit and the imaging lens, and the entire imaging optical system must be replaced.

Further, when the recording unit for emitting the laser beam is displaced from the mounting position with respect to the photosensitive member or the mounting angle of each component in the recording unit is displaced, the irradiation position of the laser beam is displaced. However, there is also a problem that image deterioration occurs.

Further, generally, as the rotation deflecting means, a polygon motor in which a mirror is attached to a motor, the polyhedral mirror is rotated, and a laser beam is deflected is used. As the synchronization detecting means, a pin photodiode having an excellent high speed response is used as an optical sensor. As described above, among the parts used in the optical scanning recording apparatus, the electric circuit parts are used for the semiconductor laser, the rotation deflection means, and the synchronization detection means. As an electric circuit part,
It is used in consideration of breakdowns, but if it breaks down unexpectedly, it will need to be replaced.

Further, in recent years, the printing speed has increased, and along with this, an air bearing excellent in high speed has come to be used in the polygon scanner, and the inside is hermetically sealed to prevent foreign matter from entering the bearing, and light such as a laser beam is emitted. Glass has come to be installed at a position where the glass passes through. As a result, the laser beam comes to be reflected on the glass surface, and the reflected light reaches the surface of the photoconductor, causing image deterioration.

The present invention solves the above-mentioned problems of the prior art. The image deterioration occurs due to the focal length variation of the imaging optics, the image deterioration occurs due to the deviation of the irradiation position of the laser beam, and the image deterioration occurs due to the reflected light. It is an object of the present invention to provide an optical scanning recording apparatus that prevents such problems and facilitates replacement and maintenance of parts.

[0011]

In order to achieve this object, an optical scanning recording apparatus according to the present invention has a rotary deflecting means for scanning a laser beam, a plurality of image forming lenses, and a plurality of reflecting mirrors. A reflecting mirror is integrally and movably arranged, and the moving point of the reflecting mirror adjusts the image forming point of the laser beam with which the surface of the photoconductor is irradiated. Further, a rotation deflecting means for scanning the laser beam, an fθ lens for forming an image of the scanned laser beam, first and second reflecting mirrors disposed integrally and movably, and reflected by the second reflecting mirror The CY lens for focusing the formed laser beam and a third reflecting mirror for irradiating the surface of the photoconductor with the laser beam are provided, and the angle of the third reflecting mirror is adjustable so that the irradiation position of the laser beam on the surface of the photoconductor can be adjusted. It is provided with a configuration arranged in. Further, an exposure optical system unit and a recording unit arranged below the exposure optical system unit are provided, and the exposure optical system unit has a platen glass on which an original is placed and which is detachably provided. And a part of the bottom plate is configured to be openable and closable, and the recording unit has a configuration in which a lid corresponding to the bottom plate configured to be openable and closable under the exposure optical system unit can be opened and closed. . Further, the recording unit is provided with a member for positioning the rotation deflecting means, a member for centering the rotation deflecting means, and a member for shielding the reflected light from the cover glass of the rotation deflecting means. It is equipped with.

[0012]

With this structure, the plurality of imaging lenses for imaging the laser beam, and the first and second reflecting mirrors disposed between the imaging lenses and integrally and movably are adjusted. As a result, it is possible to correct the focal length variation of the imaging lens, form a laser beam having a required diameter on the surface of the photoconductor, and prevent image deterioration from occurring.

Further, by disposing a reflecting mirror at a predetermined irradiation position on the surface of the photosensitive member so that the irradiation of the laser beam can be adjusted, deviation of the irradiation position of the laser beam and occurrence of image deterioration are prevented. be able to.

Further, the platen glass and a part of the bottom plate of the exposure optical system unit can be opened / closed, and the recording unit arranged below the exposure optical system unit is constructed to be opened / closed below the exposure optical system unit. The maintenance can be facilitated by opening and closing the lid corresponding to the bottom plate.

Further, by positioning and centering the rotary deflecting means and blocking the reflected light from the cover glass of the rotary deflecting means, it is possible to prevent image deterioration.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a copying machine having a structure according to the present invention. An exposure optical system 1 and a recording mechanism 2 for exchanging an exposure image of the exposure optical system 1 with a digital signal for recording. An image forming mechanism 3 that forms a toner image and transfers it to a sheet, and a sheet feeding mechanism 4 that feeds the sheet to the image forming mechanism 3.
And more. These exposure optical system 1, recording mechanism 2,
The image forming mechanism 3 and the paper feeding mechanism 4 may be configured integrally or separately. In particular, the paper feed mechanism 4 has a configuration in which a plurality of separate paper feed units 4a, 4b, 4n are stacked for each paper size.

The exposure optical system 1 moves under the platen glass 45 to scan the original and the lamp 6 and the first reflecting mirror 7 and the second reflecting mirror which moves at a speed ratio of 1/2 with the first reflecting mirror 7. A mirror 8, a lens 9, and a photoelectric conversion element 10 such as a CCD for converting an exposure image into a digital signal are provided.

The recording mechanism 2 controls the emission of a laser beam by a signal from the photoelectric conversion element 10, and scans and records through the polygon mirror 11, a lens and a reflecting mirror.

The image forming mechanism 3 includes a photoconductor 43, a charging means 13 arranged around the photoconductor 43, a developing device 14, a transfer means 15,
It has a cleaning unit 16 and the like, and forms a toner image corresponding to the original image to be exposed on the photoconductor 43 by a general electrophotographic method and transfers it to the fed paper. In front of the transfer unit where the photoconductor and the transfer unit are opposed to each other, there is provided a paper feed transport path 17 for feeding the paper received from the paper feed mechanism 4 to the transfer unit.
A pair of timing rollers 18 for aligning the leading ends and adjusting the feeding timing are provided. Further, behind the transfer section, a transfer unit 1 for transferring the transferred sheet.
9. A fixing device 20 that performs a fixing process on the sheet conveyed by the conveying unit 19, and a pair of discharge rollers 21 that discharge the sheet sent from the fixing device 20 are provided.

The paper feeding mechanism 4 is provided with papers 22 of different sizes.
And a paper feeding unit including a paper path 24. The sheet feeding units are stacked for each sheet size to enable sheet feeding corresponding to each size.

Reference numerals 25 and 26 denote cooling fans for cooling the inside of the machine, and 27 is a tray for manual feeding.
28 is a paper discharge tray.

FIGS. 2 and 3 are overall structural views of an embodiment of the optical scanning recording apparatus according to the present invention, and FIG. 3 is a plan view of FIG. 4 and 5 show the essential parts of the reflecting mirror which is integrally and movably arranged, and FIG. 6 shows the essential parts of the reflecting mirror which is arranged so as to be adjustable. 7 and 8 are configuration diagrams of the rotation deflecting means, FIGS. 9 and 10 show attachment configurations of the rotation deflecting means, and FIG. 10 is a sectional view taken along line AA. FIG. 11 shows the relationship between the focal length and the distance between lenses.

In these figures, 31 is a semiconductor laser unit, 32 is a rotary deflection means, 33 is an fθ lens, and 3
4 is a CY lens, 35 is a first reflecting mirror, 36 is a second reflecting mirror, 37 is a third reflecting mirror, 38 is a dust-proof transmission plate, 39 is a laser beam (shown by a solid line), 40 is an optical frame, 41 is an opening / closing A lid, 42 is a cover, 43 is a photoconductor, 44 is a synchronization detecting means, 45 is platen glass, 46 is a bottom plate opening / closing plate, and 47.
Is a fastening member, 48 is an exposure optical system unit frame, 49
Is a moving member for attaching the first and second reflecting mirrors, 50 is a fastening member (2 places), 51 is a movable hole (2 places), 52 is a third
A reflector mounting member, 53 is a screw adjusting tool, 54 is an elastic member, 55 is a rotation deflecting means cover glass, 56 is light reflected from the rotation deflecting means cover glass, 57 is an antireflection member,
Reference numeral 58 is a lower case of the rotation deflecting means, and 59 is a centering member. Here, the first reflecting mirror 35 and the second reflecting mirror 36 are the first,
The second reflecting mirror mounting moving member 49 is integrally arranged,
It is arranged so as to be movable by the movable hole 51 and the fastening member 50. The angle of the third reflecting mirror 37 is adjusted by moving the screw adjusting tool 53 in and out. The opening / closing lid 41 and the bottom plate opening / closing plate 46 can be attached and detached by a fastening member 47. The rotation deflecting means 32 is centered by the centering member 59, and is attached and positioned by the flat surface portion B of the rotation deflecting means 32.

The optical scanning recording apparatus having the above structure will be described. The laser beam 39 parallel-shaped by the semiconductor laser unit 31 is deflected and scanned by the rotary deflection means 32 such as a polygon scanner,
The beam diameter is narrowed by the image forming optical system of the fθ lens 33 and the CY lens 34, and the fθ scanning characteristics and surface tilt correction are given, reflected by the reflecting mirrors 35, 36 and 37, and image-formed on the surface of the photoconductor 43. At the same time, the laser beam 39 is incident on the synchronization detecting means 44 and the writing timing of the image signal is set.

At this time, the focal length of the lens is the distance from the principal point of the lens to the focal point (imaging point), and if there is variation in the focal length, the focal point, that is, the imaging point shifts. Here, as shown in FIG. 11, assuming that the fθ lens and the CY lens are one imaging lens, the distance between the lenses is tc,
As for the relationship between the distance between the lenses and the focal length f, when the curvature of the fθ lens is r1, the curvature of the CY lens is r2, and the refractive index is n,

[0027]

[Equation 1]

From the relational expression (3), when the focal length f is increased by Δf due to the variation, it suffices to reduce tc, that is, the distance between the lenses.

Therefore, the interval of tc is moved according to the variation of the focal length f as in the present invention.

That is, by moving the first and second reflecting mirrors arranged between the imaging lenses, tc changes, so that the focal point is formed.

It is obvious that a plurality of reflecting mirrors are inappropriate because a single reflecting mirror changes the optical path.

If the positional relationship between the fθ lens and the polygon scanner, and the CY lens and the image forming point is changed, the fθ characteristic of the lens and the optical position characteristic of the surface tilt correction are affected, which is not preferable.

Further, the focal length variation of the imaging lens can be corrected on the imaging lens side, and it can be separated from the semiconductor laser unit.

When the actual image formation is investigated with the above configuration,
If there is variation in the focal length and the movement of the reflecting mirror is not corrected, a 1 mm image position deviation occurs. At this time, the laser beam diameter on the surface of the photoconductor is smaller than the regular laser beam diameter. The laser beam diameter was increased by 20%. However, the correction has made it possible to irradiate the surface of the photoconductor with a regular laser beam diameter. As a result, the occurrence of image deterioration could be improved.

Next, the laser beam 39 parallel-shaped by the semiconductor laser unit 31 is used as the polygon scanner 3
2, the laser beam is deflected and scanned, and the fθ lens 33,
The beam diameter is narrowed by the image forming optical system of the CY lens 34, fθ scanning characteristics and surface tilt correction are given, reflected by the reflecting mirrors 35, 36 and 37, and image-formed on the surface of the photoconductor 43.

At this time, if a displacement occurs between the photoconductor inside the image forming mechanism 3 and the mounting position of the recording mechanism, that is, the optical frame 40, a displacement from the regular irradiation position occurs, resulting in a print printing displacement. Occurs. At the same time, since the photosensitive member is drum-shaped, the positional deviation causes the shape of the laser beam diameter to change at the irradiation point of the photosensitive member even if the regular laser beam diameter is emitted from the recording mechanism. In addition, the displacement of the position occurs due to the mounting of each mirror and the variation in the accuracy of each component, which causes a change in the optical path and causes the displacement of the irradiation position.

Here, if the angles of the first and second reflecting mirrors are adjusted, there is a risk that they will deviate from the lens effective range of the CY lens. Therefore, the angle adjustment of the first and second reflecting mirrors is inappropriate due to the relationship with the CY lens. is there.

Therefore, as in the present invention, the irradiation position can be changed by adjusting the angle of the third reflecting mirror, and the irradiation of the laser beam onto the irradiation position on the surface of the photosensitive member can be performed, resulting in print printing deviation and The deviation of the laser beam diameter can be prevented, and the occurrence of image deterioration can be prevented.

Next, the platen glass and a part of the bottom plate of the exposure optical system unit can be opened / closed, and the recording unit arranged below the exposure optical system unit can be opened / closed below the exposure optical system unit. The lid corresponding to the opened bottom plate can be opened and closed, and as shown in FIG. 3, the semiconductor laser unit equipped with a polygon scanner and a semiconductor laser and the electric circuit parts of the synchronization detecting means correspond to the lid that can be opened and closed. If the component fails, the exposure optical system unit will be removed as in the past, then the recording mechanism unit will be removed from the main unit and replaced, and the work will be reversed. Is reduced, and replacement maintenance can be easily performed without removing the exposure optical system unit and the recording mechanism unit.

Next, in general, the dimensional tolerance of the laser incident angle from the semiconductor laser unit and the relative position of the polygon scanner and the imaging lens is required to be ± 0.05 to ± 0.03 mm. At this time, if the processing accuracy of the frame is pursued at the polygon scanner mounting portion of the optical frame, the accuracy can be easily obtained by holding it at three points as shown in FIGS. Also, since there is a relief except for three-point support, it is easy to process.

Further, when the reflected light from the cover glass surface of the polygon scanner is incident on the surface of the photosensitive member, the image becomes uneven. However, as shown in FIG. 8, the cover glass surface of the polygon scanner is secured at a fixed position by restricting the flat surface portion B. At this time, if the fixed position is not secured, the positional relationship of the reflected light may fluctuate and may enter the photoconductor through the optical path 56, but the position of the glass is forcibly secured at the fixed position. By doing so, it is possible to irradiate the light reflected from the glass surface to a fixed position (optical path 57), and furthermore, by installing an antireflection member at the irradiated position, the irradiation laser beam is positively activated. Moreover, it can be reliably removed.

[0042]

As described above, according to the present invention, a plurality of reflecting mirrors which are integrally and movably arranged are arranged between the image forming lenses, and the plurality of reflecting mirrors are moved to form the image forming lens. Even if there is a variation in the focal length, it can be corrected in accordance with the variation in the focal length, so that a laser beam can be imaged on the surface of the photoconductor, and an excellent device that can prevent image deterioration from occurring. Can be realized.

Further, since the third reflecting mirror can adjust the irradiation position of the laser beam on the surface of the photosensitive member, it can be adjusted according to the deviation of the relative position of each unit and each component, so that the print printing deviation and the laser It is possible to realize an excellent apparatus capable of preventing the image deterioration due to the beam diameter deviation.

Further, by making the platen glass, a part of the bottom plate of the exposure optical system unit, and the lid of the recording unit openable and closable, it is possible to realize an excellent apparatus in which each unit can be easily maintained.

Further, the centering position of the rotary deflecting means and the position of the reflected light from the cover glass are made constant so that the reflected light can be shielded, so that the image forming lens, the semiconductor laser unit and the rotary deflecting means are arranged. It is possible to realize an excellent device that can secure the relative positional relationship, prevent the reflected light from the cover glass of the rotation deflecting means from entering the surface of the photoconductor, and prevent the occurrence of image deterioration.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the overall configuration showing an embodiment of an optical scanning recording apparatus of the present invention.

FIG. 2 is an overall configuration diagram showing an embodiment of an optical scanning recording apparatus of the present invention.

FIG. 3 is an overall configuration diagram showing an embodiment of an optical scanning recording apparatus of the present invention, showing the plane of FIG.

FIG. 4 is an explanatory diagram of a main part of a movable reflecting mirror of the optical scanning recording device.

5 is a diagram showing a plane of FIG. 4 for explaining a main part of a movable reflecting mirror of the optical scanning recording apparatus.

FIG. 6 is an explanatory diagram of a main part of an adjustable reflecting mirror of the optical scanning recording apparatus.

FIG. 7 is an explanatory view of a rotation deflection unit of the optical scanning recording device,
Explanatory drawing of main part of laser beam optical path

FIG. 8 is an explanatory view of a rotation deflecting unit of the optical scanning recording device,
The figure which showed the plane of FIG. 7 in the explanatory view of the principal part of a laser beam optical path.

FIG. 9 is an explanatory diagram of a mounting portion of a rotation deflection unit of the optical scanning recording apparatus.

FIG. 10 is an explanatory view of a mounting portion of a rotation deflection unit of the optical scanning recording device, showing a cross section taken along line AA of FIG. 9;

FIG. 11 is a relationship diagram between a focal length and a distance between lenses

FIG. 12 is an explanatory diagram of a configuration of a conventional optical scanning recording device.

FIG. 13 is an explanatory diagram of a main part of a conventional optical scanning recording device.

FIG. 14 is an overall configuration diagram of a conventional copying machine.

FIG. 15 is a configuration diagram of a semiconductor laser unit.

[Explanation of symbols]

 31 semiconductor laser unit 32 rotation deflection means 33 fθ lens 34 CY lens 35 first reflecting mirror 36 second reflecting mirror 37 third reflecting mirror 41 open / close lid 43 photoconductor 45 platen glass 46 bottom plate opening / closing plate 55 cover glass 57 antireflection member 59 Centering member

Claims (4)

[Claims] 1. A rotary deflection means for scanning a laser beam, a plurality of image forming lenses for forming an image of the scanned laser beam, and a plurality of integrally arranged movable lenses between the image forming lenses. The optical scanning recording apparatus is characterized in that the image forming point of the laser beam with which the surface of the photoconductor is irradiated is adjusted by moving the reflecting mirror. 2. A rotation deflection means for scanning a laser beam, and an fθ lens for forming an image of the scanned laser beam,
First and second reflecting mirrors integrally and movably arranged, and C for focusing the laser beam reflected by the second reflecting mirror
Third lens for irradiating the surface of the photoconductor with the Y lens and the laser beam
An optical scanning recording apparatus, comprising: a reflecting mirror, wherein the third reflecting mirror is arranged so that an angle of the laser beam can be adjusted on the photosensitive member surface. 3. An exposure optical system unit, and a recording unit disposed below the exposure optical system unit, wherein the exposure optical system unit is provided so that a document is placed on the upper portion thereof and is detachably attached. The platen glass and a part of the bottom plate are configured to be openable and closable, and the recording unit is configured to open and close a lid of a portion corresponding to the openable and closable bottom plate under the exposure optical system unit. Optical scanning recording device. 4. A recording unit, a positioning portion for positioning the rotation deflecting means, a centering portion for centering the rotation deflecting means, and an antireflection member for shielding reflected light from the cover glass of the rotation deflecting means. An optical scanning recording apparatus comprising a recording unit.