JP5843473B2 - Color image forming apparatus - Google Patents

Description

The present invention is a copying machine, a color image forming apparatus including the optical scanning equipment such as a printer.

  In an image forming apparatus such as a laser beam printer, a configuration is known in which a photosensitive drum is exposed and scanned by a laser scanning device which is an exposure device to form an electrostatic latent image. In recent years, high-speed color printing has been demanded for image forming apparatuses, and a so-called tandem system that includes process units (four colors of yellow, magenta, cyan, and black (hereinafter referred to as YMCK)) including process units including a photosensitive drum. It is common to have a configuration. As a laser scanning device mounted on a tandem image forming apparatus, there is a laser scanning device having a so-called 2-in-1 method that emits scanning light of two colors and scans photosensitive drums of two colors of YMCK. Two laser scanning devices are mounted on one image forming apparatus. There is also a 1 in 1 type laser scanning device that emits scanning light of one color from one unit.

  In general, in a tandem image forming apparatus using four color process units, the irradiation position of the laser scanning device gradually shifts while the apparatus is continuously operated, and the shift amount is slightly different for each color. Therefore, there is a problem that color misregistration occurs. This is because the heat generated by the rotation of the polygon mirror and the heat from the fixing unit cause distortion in the housing of the laser scanning device, the posture of the mirror and lens in the housing changes, and the scanning line on the photosensitive drum changes. This is because a deviation occurs in the irradiation position. The shift includes a registration shift in which each scanning line is shifted in parallel to the sub-scanning direction, and an inclination shift in which each scanning line is not parallel in the sub-scanning direction. The following proposals have been made as a method for suppressing such color misregistration.

  For example, in Patent Document 1, in an image forming apparatus equipped with a common 2-in-1 laser scanning device, each laser scanning device is supported so as to be movable in a predetermined direction, and can be rotated around a predetermined rotation axis. A technique that can independently adjust the inclination of the scanning line is disclosed. In this technique, since the entire 2 in 1 laser scanning device is moved and adjusted, the adjustment mechanism itself becomes large. Furthermore, since all the scanning lines move simultaneously during adjustment, the adjustment becomes very complicated, and even if the initial state can be adjusted, it is not possible to cope with a tilt shift that changes every time during operation of the image forming apparatus. As a method of adjusting the changing inclination deviation, the inclination deviation amounts of the four colors are measured at regular time intervals during operation of the apparatus, and an imaging lens having a refractive power in the sub-scanning direction is used in accordance with the measurement, using an inclination correction motor. A method of aligning scanning lines by rotating around an optical axis is known.

Japanese Patent Laid-Open No. 10-181087

  When adjusting the inclination deviation of each scanning line by the above method, a method is generally used in which any one of the four colors is used as a reference color and the scanning lines of other colors are aligned with the scanning line of the reference color. In this method, since it is not necessary to correct the inclination shift of the reference color scanning line, it is not necessary to install an inclination correction motor for the reference color. As shown in FIG. 7, the inclination correction motor 23 is fixed inside the housing 1 as a component of the laser scanning device. Therefore, for example, if it is attempted to omit an inclination correction motor for a reference color which is not necessary in the above-described 2-in-1 laser scanning apparatus, there are the following problems. That is, the laser scanning device that emits the scanning light including the reference color and the laser scanning device that emits the scanning light of other colors must be manufactured as different laser scanning devices. The process becomes complicated. In order to avoid this, in order to make all the laser scanning devices to be mounted in common, it is necessary to mount an inclination correction motor on the laser scanning device for the reference color, which should not be necessary.

  Further, in a configuration that is often used in the past and that determines the posture of the imaging lens by adjusting the phase of the cam 22 by the tilt correction motor 23 as shown in FIG. 7, the phase of the cam 22 when the tilt correction motor 23 is not mounted. There was also a problem that was not fixed.

  The present invention has been made under such circumstances. In a tandem type image forming apparatus equipped with a plurality of optical scanning devices, optical scanning is performed regardless of whether the optical scanning device is for a reference color. The purpose is to share the equipment.

  In order to achieve the above object, the present invention has the following configuration.

(1) a first photosensitive member and the Oite the color image forming equipment having a second photoreceptor, first and second optical scanning device corresponding to each of the first and second photoconductor a light source for emitting a light beam for forming an electrostatic latent image on the photosensitive member corresponding to the deflection means for deflecting said light beam to scan on the photosensitive member in which the light beam corresponds, An optical member disposed on an optical path of the light beam between the deflecting unit and the corresponding photosensitive member, a housing to which the light source is attached, and housing the deflecting unit and the optical member therein, and the housing A support portion that supports the optical member inside the housing and a cam mechanism, and changes the posture or position of the optical member supported by the support portion according to the operation of the cam mechanism. adjustment mechanism is possible The has an opening which is provided at a position corresponding to the position of the cam mechanism, respectively, it has an external from attachable drive motor of the first and second optical scanning device of the housing, the first In the optical scanning device, a drive motor for supplying power to the cam mechanism is not attached to the first optical scanning device, the adjustment mechanism is fixed to the housing, and the optical member is The second optical scanning device is attached with a drive motor for supplying power to the cam mechanism by being fixedly held in the housing by an adjustment mechanism fixed to the housing. the cam mechanism before by the cam mechanism is rotated by receiving the power of the drive motor from the rotational axis passing through the opening, provided in the second optical scanning device is rotated Color image forming, wherein the adjustment mechanism is adjustable to the imaging position of the light beam in the second photoreceptor on by changing the attitude or position of the supported the optical member to the support section apparatus.

(2) a first photosensitive member and the Oite the color image forming equipment having a second photoconductor, an optical scanning apparatus, a for forming an electrostatic latent image on the first photoconductor on A first light source that emits one light beam, a second light source that emits a second light beam for forming an electrostatic latent image on the second photoconductor, and the first light beam. Scanning the first photoconductor, and deflecting means for deflecting the first light beam and the second light beam so that the second light beam scans the second photoconductor . A first optical member disposed on an optical path of the first light beam between the deflecting means and the first photoconductor; and the first optical member between the deflecting means and the second photoconductor. A second optical member disposed on an optical path of the second light beam, the first light source and the second light source, and the deflection unit. A housing that houses the first optical member and the second optical member, a first support portion that is attached to the housing and supports the first optical member inside the housing, and a first support portion 1st adjustment mechanism which can change the attitude | position or position of the said 1st optical member supported by the said 1st support part according to operation | movement of the said 1st cam mechanism. And a second support portion that is attached to the inside of the housing and supports the second optical member inside the housing, and a second cam mechanism, and the second cam mechanism is operated according to the operation of the second cam mechanism. A second adjustment mechanism capable of changing the posture or position of the second optical member supported by the second support portion, and a first adjustment mechanism provided at a position corresponding to the arrangement position of the first cam mechanism. 1 of the opening, the arrangement position of the second cam mechanism And a second opening provided in the corresponding positions, respectively, have external from attachable drive motor of the optical scanning device of the housing, the first cam mechanism of the first adjusting mechanism The drive motor for supplying power is not attached , the first adjustment mechanism is fixed to the housing, and the first optical member is fixed to the housing. held fixed in the housing by a mechanism, wherein the said second cam mechanism of the second adjustment mechanism is mounted a drive motor for powering the second cam mechanism rotating shaft that passes through the opening rotated by kicking receive the power of the drive motor from the position of the second of the adjusting mechanism is supported by the second supporting portion and the second optical member by the second cam mechanism is rotated Or changed position The color image forming apparatus can adjust the image-forming position of the light beam on the second photosensitive member .

  According to the present invention, in a tandem image forming apparatus equipped with a plurality of optical scanning devices, the optical scanning devices can be shared regardless of whether the optical scanning device is for the reference color.

Schematic of the image forming apparatus of the embodiment Main scanning sectional view and longitudinal sectional view of optical path of optical scanning device of embodiment The figure which shows the principle of inclination correction of the optical scanning device of an Example The figure which shows the inclination adjustment part and inclination correction motor of an Example The figure which shows the state before mounting | wearing of the inclination correction motor of an Example, and after mounting | wearing. The figure explaining the locking mechanism of the cam of an Example The figure which shows the internal structure of the optical scanning apparatus of a prior art example

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

[Configuration of Image Forming Apparatus]
FIG. 1 shows an example of a color image forming apparatus provided with a plurality of optical scanning devices of this embodiment. In the following description, a laser scanning device using a laser as a light source will be described as an optical scanning device. The image forming apparatus scans the photosensitive drum 10, which is an image carrier (photosensitive member) in the process unit 300, and a process unit 300 that forms a toner image with a laser beam. It has a laser scanning device 100 for forming an image. Further, the image forming apparatus includes an intermediate transfer belt 400 that collectively transfers toner images developed by the process unit 300 of four colors (multiple colors) onto a superposed paper, and a fixing unit 500 that fixes the toner images transferred onto the paper. The process unit 300 is provided for four colors of YMCK. Each of the process units 300 includes a photosensitive drum unit 310 and a developing unit 320. The developing unit 320 converts an electrostatic latent image formed on the photosensitive drum 10 by the laser scanning device 100. A toner image is formed by attaching toner. The laser scanning device 100 arranges two units emitting two systems of scanning light, and scans the photosensitive drum 10 of YM or CK, respectively. The toner images of the respective colors are superimposed on the intermediate transfer belt 400 at the first transfer portion where the photosensitive drum 10 and the intermediate transfer belt 400 are in contact with each other. The images are transferred all at once to the conveyed paper. The sheet on which the toner images of four colors are transferred is conveyed to the fixing unit 500, and is nipped by the fixing roller 510, and heat and pressure are applied to fix the toner image on the sheet.

[Configuration of laser exposure apparatus]
FIG. 2A is a diagram of a main scanning cross section in which the optical path of the 2-in-1 laser scanning apparatus of the present embodiment is developed on one plane. The main scanning section refers to a plane parallel to the scanning direction and perpendicular to the rotation axis of the polygon mirror 5. A plane that includes the optical axis and is perpendicular to the main scanning section is defined as a sub-scanning section. In FIG. 2A, the laser beam (light beam) emitted from the light source 2 is converted into parallel light by the collimator lens 3, and the sub-scanning direction (the scanning direction on the reflecting surface of the polygon mirror 5) is converted by the cylindrical lens 4 immediately after. In the orthogonal direction). Then, after being shaped into a predetermined shape by the diaphragm 15, a linear image is formed on the reflection surface of the polygon mirror 5. The collimator lens 3, the cylindrical lens 4, and the stop 15 constitute an imaging optical system. The laser beam imaged on the reflecting surface of the polygon mirror 5 is deflected by the rotation of the polygon mirror 5 and imaged on the photosensitive drum 10 (on the photosensitive member) by the fθ lens M (scanning optical system) and scanned at a constant speed. An electrostatic latent image is formed. That is, the fθ lens M is disposed on the optical path of the laser beam between the polygon mirror 5 and the photosensitive drum 10. The fθ lens M includes a first imaging lens 6 and a second imaging lens 7. Further, as shown in FIG. 2A, this optical system is composed of a first scanning path and a second scanning path symmetrically across the polygon mirror 5, and these scan different photosensitive drums 10. FIG. 2B is a longitudinal sectional view of a laser scanning device in which the optical system described in FIG. In FIG. 2A, the optical system has been described as being developed in a plane, but in reality, the laser exposure apparatus exposes and scans the photosensitive drum 10 through a three-dimensional path using a folding mirror as shown in FIG. 2B. doing. Specifically, for each of the first and second scanning paths, the first mirror 8 and the second imaging lens 7 are provided between the first imaging lens 6 and the second imaging lens 7 of the fθ lens M. After passing through, the second mirror 9 is provided. The scanning light is finally guided to the photosensitive drum 10 by a total of two turns.

[Tilt adjustment method]
FIG. 3A is a diagram showing a method for adjusting the tilt deviation. FIG. 3B is a view seen from the direction of the arrow A in FIG. The second imaging lens 7 of the fθ lens M is bonded and fixed to the lens support plate 20. The lens support plate 20 is urged to a surface perpendicular to the optical axis of the housing 1 by a fixing spring (not shown), and one end of the lens support plate 20 is supported by the rotation shaft 20a and the other end is adjusted in height. It is supported by the member 21. And it is rotatably supported according to the attitude | position of the height adjustment member 21 centering on the rotating shaft 20a, contacting the contact surface as a whole. The second imaging lens 7 is given a curvature in the sub-scan section as shown in FIG. 3C, and has a refractive power in the sub-scan direction. The height adjusting member 21 is supported like a seesaw, and the other abutting surface is in contact with the cam 22. The cam 22 has a gear on the outer periphery, and the gear is engaged with a gear of an inclination correction motor 23 (drive motor). Then, the phase changes of the cam 22 by the rotation of the tilt correction motor 23, the accompanying end height of the second imaging lens 7 which, Ru is adjusted attitude through the height adjusting member 21.

  When the second imaging lens 7 is rotated in such a configuration, the amount of movement of the second imaging lens 7 in the sub-scanning direction increases as the distance from the side closer to the rotation axis 20a increases. FIG. 3C is a diagram schematically showing the relationship between the position of the light beam passing through the second imaging lens 7 and refraction. The imaging lens has a refractive power in the sub-scanning direction, and the light beam A passing through the center of the lens travels straight to A ′, whereas the light beam B and the light beam C are farther from the center of the optical axis of the lens as lens characteristics. Since it tends to advance inward as it passes, the direction is changed to B ′ and C ′, respectively. Here, three light fluxes A to C are representatively described, but actually, the direction of the light flux continuously changes in accordance with the passing position of the lens. That is, if the amount of movement in the sub-scanning direction of the lens far from the rotation axis 20a is adjusted by rotating the second imaging lens 7, the image formation position of the light beam is accordingly farther from the side closer to the rotation axis 20a. It can be changed continuously toward the side. As a result, it is possible to adjust the inclination deviation of the scanning line on the photosensitive drum (on the image carrier).

[Configuration of tilt adjustment unit]
Next, the tilt adjustment unit of the laser scanning device 100 will be described in more detail. FIG. 4A shows a part of the laser scanning device, and is a cross-sectional view showing the positional relationship between the housing 1, the tilt adjustment unit, and the tilt correction motor 23. FIG. 4B shows only the inclination correction motor 23. Unlike the conventional laser scanning device, the inclination correction motor 23 can be attached to and detached from the housing 1 from the outside. FIG. 5 is a perspective view of the tilt adjusting unit viewed from the front and back directions with and without the tilt correction motor 23 mounted. Note that FIG. 3B described above is a diagram obtained by vertically inverting FIG. 4A. FIG. 5A is a view of the tilt adjustment unit to which the tilt correction motor 23 is not attached as viewed from the front side, and FIG. 5B is a view of the same from the back side. FIG. 5C is a view of the tilt adjustment unit to which the tilt correction motor 23 is attached as viewed from the front side, and FIG. 5D is a view of the same from the back side. As shown in FIG. 4 (a), the tilt adjusting unit including the height adjusting member 21, the cam 22, and the cam holder 24 is housed in the housing 1, whereas the tilt correcting motor 23 is used in the housing 1. It is attached outside. The correction motor 23 is detachable, and the power of the correction motor 23 adjusts the posture or position of the second imaging lens 7 through a positioning hole 1a (opening) provided in the housing 1. As shown in FIG. 4B, the tilt correction motor 23 has a motor gear 23b on the shaft and a projection 23c on the bottom of the shaft, and a lock release pin 23a is installed at a predetermined position. After passing the motor gear 23b through the positioning hole 1a provided in the housing 1 shown in FIG. 5B, the projection 23c is fitted and positioned with the positioning hole 1a, and is fixed to the housing 1 at two screws. (FIG. 5D).

[Cam locking mechanism]
Next, the locking mechanism of the cam 22 will be described with reference to FIG. In FIG. 6, a part of the cam 22 and the cam holder 24 is omitted for easy understanding of the mechanism. The cam 22 is pivotally supported by a cam holder 24, has a cam surface on the lower surface, a gear on the outer periphery, and a lock hole 22a on the inner peripheral side from the cam surface. The cam holder 24 is provided with a lock pin 24 a at a position facing the lock hole 22 a of the cam 22. When the tilt correction motor 23 is not attached to the housing 1, the lock pin 24 a and the lock hole 22 a are fitted, and the rotational phase of the cam 22 is locked at the initial position to restrain the cam 22. A slit is formed around the lock pin 24 a and can be elastically deformed with respect to the base portion of the cam holder 24. On the other hand, as described above, the tilt correction motor 23 is provided with the lock release pin 23a. When the tilt correction motor 23 is attached to the housing 1 from the outside, the lock release pin 23a pushes up the lock pin 24a and the cam 22 Is unlocked. At the same time, the motor gear 23 b of the inclination correction motor 23 and the outer peripheral gear shape of the cam 22 mesh with each other, and the unlocked cam 22 is in a state where it can be rotated by the power from the inclination correction motor 23.

  As described above, the inclination correction motor 23 is externally attached to the laser scanning device, thereby optimizing the number of the inclination correction motors 23 and making each laser scanning device common so that the manufacturing process and the component management process can be performed. Can be simplified. Even when the inclination correction motor 23 is not attached, the phase of the cam 22 can be fixedly held. That is, in an image forming apparatus having a plurality of laser scanning devices, a laser scanning device that emits scanning light of a reference color and a laser scanning device other than that (other than the optical scanning device) differ except for the inclination correction motor 23. It is not necessary to manufacture as a laser scanning device. In the laser scanning device that emits the scanning light of the reference color, all of the laser scanning devices that emit scanning light of colors other than the scanning light for the reference color without mounting the inclination correction motor 23 for the reference color. The inclination correction motor 23 for the other colors may be attached. When the inclination correction motor 23 for the reference color is not attached, the phase of the cam 22 is fixed by fitting the lock pin 24a and the lock hole 22a as described above.

  As described above, according to this embodiment, in a tandem type image forming apparatus having a plurality of optical scanning devices mounted thereon, a plurality of optical scanning devices can be shared regardless of whether or not the reference color optical scanning device is used. it can.

21 Height adjustment member 22 Cam 22a Lock hole 23 Tilt correction motor 23a Lock release pin

Claims (5)

Oite color image forming equipment having a first photoconductor and the second photoconductor,
A first and a second optical scanning device corresponding to the first and second photoconductors, respectively, and a light source that emits a light beam for forming an electrostatic latent image on the corresponding photoconductor; wherein a deflecting means for deflecting the light beam so as to scan the photosensitive member, an optical member disposed on an optical path of the light beam between the photosensitive member corresponding to said deflecting means for the light beam corresponding And a housing to which the light source is attached and which houses the deflection means and the optical member, and a support portion and a cam mechanism which are attached to the inside of the housing and support the optical member inside the housing, An adjustment mechanism capable of changing the posture or position of the optical member supported by the support portion according to the operation of the cam mechanism, and an opening provided at a position corresponding to the arrangement position of the cam mechanism. That A, has a first and second optical scanning devices can be attached to the drive motor from the outside of the housing,
In the first optical scanning device, a drive motor for supplying power to the cam mechanism is not attached to the first optical scanning device, the adjustment mechanism is fixed to the housing, and the optical The member is fixedly held in the housing by an adjustment mechanism fixed to the housing,
In the second optical scanning device, a drive motor for applying power to the cam mechanism is attached to the second optical scanning device, and the cam mechanism is driven by a rotating shaft passing through the opening. Rotate by receiving
When the cam mechanism provided in the second optical scanning device rotates, the adjustment mechanism changes the posture or position of the optical member supported by the support portion, whereby the second photosensitive member on the second photoconductor is changed. A color image forming apparatus capable of adjusting an imaging position of a light beam . Oite color image forming equipment having a first photoconductor and the second photoconductor,
An optical scanning apparatus, the first a first light source for emitting on the photoreceptor a first light beam for forming an electrostatic latent image, an electrostatic latent image on said second photosensitive body on A second light source that emits a second light beam for forming the first light beam, the first light beam scans on the first photoconductor , and the second light beam emits the second photoconductor And deflecting means for deflecting the first light beam and the second light beam so as to scan, and an optical path of the first light beam between the deflecting means and the first photoconductor. The first optical member , the second optical member disposed on the optical path of the second light beam between the deflecting means and the second photosensitive member, the first light source, and the A housing to which a second light source is attached and which houses the deflecting means, the first optical member, and the second optical member; A first support portion that is attached to the interior of the housing and supports the first optical member within the housing; and a first cam mechanism, wherein the first cam mechanism is operated according to an operation of the first cam mechanism. A first adjusting mechanism capable of changing a posture or a position of the first optical member supported by a support portion; and a first adjusting mechanism which is attached to the inside of the housing and supports the second optical member in the housing. And changing the posture or position of the second optical member supported by the second support unit according to the operation of the second cam mechanism. A second adjustment mechanism capable of operating, a first opening provided at a position corresponding to the arrangement position of the first cam mechanism, and a position corresponding to the arrangement position of the second cam mechanism. and a second opening, respectively, outside of the housing Has an optical scanning apparatus capable of mounting the drive motor from
A drive motor for supplying power is not attached to the first cam mechanism of the first adjustment mechanism, the first adjustment mechanism is fixed to the casing, and the first optical member Is fixedly held in the housing by the first adjusting mechanism fixed to the housing,
Wherein the second cam mechanism of the second adjustment mechanism is mounted a drive motor for powering the second cam mechanism that delivers receive the power of the drive motor from the rotational axis passing through the opening Rotated by
When the second cam mechanism rotates, the second adjustment mechanism changes the posture or position of the second optical member supported by the second support portion, thereby allowing the second photoconductor to move on the second photoconductor. A color image forming apparatus capable of adjusting an image forming position of the light beam in the apparatus. The optical member provided in the first optical scanning device and the optical member provided in the second optical scanning device are imaging lenses ,
The support portion provided in the first optical scanning device and the support portion provided in the second optical scanning device are each a support portion supported at one end rotatably by an axis,
In the first optical scanning device, the adjustment mechanism of the first optical scanning device is a lock pin that pivotally supports the cam mechanism of the first optical scanning device and fixes the cam mechanism so as not to rotate. It has a cam holder over with,
In the second optical scanning device, the adjustment mechanism of the second optical scanning device is a lock pin that pivotally supports the cam mechanism of the second optical scanning device and fixes the cam mechanism so as not to rotate. Having a cam holder having
The drive motor has a gear fixed to the rotary shaft of the drive motor meshing with the gear of the cam mechanism, and the lock release pin for releasing the fixing of the cam mechanism by the locking pin before Symbol cam holder, a,
The cam mechanism provided in the first optical scanning device is fixed by the lock pin of a cam holder provided in the first optical scanning device ,
The lock pin of the cam holder provided in the second optical scanning device is released by the lock release pin of the drive motor , and the cam mechanism provided in the second optical scanning device includes the cam 2. The color image forming apparatus according to claim 1 , wherein the color image forming apparatus is rotated by receiving power from the gear of the drive motor meshing with a gear of a mechanism . The first optical member and the second optical member are imaging lenses,
One end of each of the first support part and the second support part is rotatably supported by a shaft,
The first adjustment mechanism has a cam holder having a lock pin that pivotally supports the cam mechanism included in the first adjustment mechanism and fixes the cam mechanism so as not to rotate.
The second adjustment mechanism includes a cam holder having a lock pin that pivotally supports the cam mechanism included in the second adjustment mechanism and fixes the cam mechanism so as not to rotate.
The drive motor includes a gear that is fixed to a rotation shaft of the drive motor and meshes with a gear of the cam mechanism, and a lock release pin that releases the fixation of the cam mechanism by the lock pin of the cam holder,
The cam mechanism provided in the first adjustment mechanism is fixed by the lock pin of a cam holder provided in the first adjustment mechanism,
The lock pin of the cam holder provided in the second adjustment mechanism is released by the lock release pin of the drive motor, and the cam mechanism provided in the second adjustment mechanism is The color image forming apparatus according to claim 2, wherein the color image forming apparatus rotates by receiving power from the gear of the drive motor meshing with the gear. Before Kiyuizo lens, a color image forming apparatus according to claim 3 or 4, characterized in that a fθ lens.

Images