Patent Grant
7230638
The present invention relates to an image forming apparatus having a plurality of laser scanner units, such as a color copying machine or a color printer.
As a color copying machine, a color printer or the like using electrophotography, there is available one in which four photosensitive members are arranged in tandem. A tandem-type image forming apparatus is advantageous in that it allows the use of relatively many types of recording media and that it has high recording speed, and the tandem-type image forming apparatus is becoming mainstream as a recent color image forming apparatus.
As a form of such a tandem-type image forming apparatus, Japanese Patent Application Laid-Open No. 2003-279875 and Japanese patent Application Laid-Open No. H10-221617 disclose apparatuses in which two laser scanner units are provided for four photosensitive members (2-box type). In each of the laser scanner units mounted in this type of image forming apparatus, one polygon mirror is used for two optical systems (common use), thereby achieving a reduction in the size and cost of the image forming apparatus.
In some tandem-type image forming apparatuses, the four photosensitive members are not arranged in a straight line. Japanese Patent Application Laid-Open No. 2001-42595 discloses a construction in which, of the first through fourth photosensitive members, the second and third photosensitive members protrude toward the transfer belt by approximately 1 mm. In the apparatus as disclosed in the above-mentioned publication, in the full color printing mode, the transfer belt for conveying recording sheets is in contact with all the four photosensitive members, whereas, in the monochrome printing mode, the transfer belt is separated from the three photosensitive members other than the photosensitive member for black. Since the second and third photosensitive members protrude toward the transfer belt by approximately 1 mm, the recording sheet carrying surface of the transfer belt is flat at the time of monochrome printing while maintaining an appropriate contact state of the transfer belt with respect to each photosensitive member at the time of full color printing, so that it is possible to prevent the recording sheet from being separated from the transfer belt.
In the apparatus disclosed in this publication, the laser scanner units corresponding to the four photosensitive members constructed of four separate units (4-box type), so it is possible to realize an optically appropriate layout by shifting the second and third laser scanner units, which are of the same construction, in parallel toward the transfer belt by the same distance by which the second and third photosensitive members protrude toward the transfer belt (which, in this case, is 1 mm).
However, when applying a 2-box type laser scanner unit, which is advantageous from the viewpoint of achieving a reduction in size and cost, to an apparatus in which the four photosensitive members are not arranged in a straight line, the following problem is involved.
For example, in the image forming apparatus shown in
The present invention has been made in view of the above problem in the prior art. It is an object of the present invention to provide an image forming apparatus which helps to achieve a reduction in cost.
Another object of the present invention is to provide an image forming apparatus in which the optical characteristics of optical elements mounted in a first laser scanner unit can be made the same as those of optical elements mounted in a second laser scanner unit.
Further another object of the present invention is to provide an image forming apparatus including:
a first laser scanner unit for emitting a first laser beam and a second laser beam, which has a first laser source for generating the first laser beam, a second laser source for generating the second laser beam, and a first rotary mirror for deflecting the first laser beam and the second laser beam generated from the first laser source and the second laser source;
a second laser scanner unit for emitting a third laser beam and a fourth laser beam, which has a third laser source for generating the third laser beam, a fourth laser source for generating the fourth laser beam, and a second rotary mirror for deflecting the third laser beam and the fourth laser beam generated from the third laser source and the fourth laser source;
a first photosensitive member irradiated with the first laser beam;
a second photosensitive member irradiated with the second laser beam;
a third photosensitive member irradiated with the third laser beam; and
a fourth photosensitive member irradiated with the fourth laser beam, characterized in that:
an optical path configuration for the third laser beam from the third laser source to the third photosensitive member is substantially the same as an optical path configuration for the first laser beam from the first laser source to the first photosensitive member;
an optical path configuration for the fourth laser beam from the fourth laser source to the fourth photosensitive member is substantially the same as an optical path configuration for the fourth laser beam from the second laser source to the second photosensitive member; and
a second virtual line connecting a rotation center of the third photosensitive member and a rotation center of the fourth photosensitive member is inclined with respect to a first virtual line connecting a rotation center of the first photosensitive member and a rotation center of the second photosensitive member, and an angle made by a rotation axis of the second rotary mirror and the second virtual line being the same as an angle made by a rotation axis of the first rotary mirror and the first virtual line.
Further another object of the present invention is to provide an image forming apparatus including:
a first laser scanner unit for emitting a first laser beam and a second laser beam, which has a first laser source for generating the first laser beam, a second laser source for generating the second laser beam, and a first rotary mirror for deflecting the first laser beam and the second laser beam generated from the first laser source and the second laser source;
a second laser scanner unit for emitting a third laser beam and the fourth laser beam, which has a third laser source for generating the third laser beam, a fourth laser source for generating the fourth laser beam, and a second rotary mirror for deflecting the third laser beam and the fourth laser beam generated from the third laser source and the fourth laser source;
a first photosensitive member irradiated with the first laser beam;
a second photosensitive member irradiated with the second laser beam;
a third photosensitive member irradiated with the third laser beam; and
a fourth photosensitive member irradiated with the fourth laser beam, characterized in that:
an optical path configuration for the third laser beam from the third laser source to the third photosensitive member is substantially the same as an optical path configuration for the second laser beam from the second laser source to the second photosensitive member;
an optical path configuration for the fourth laser beam from the fourth laser source to the fourth photosensitive member is substantially the same as an optical path configuration for the first laser beam from the first laser source to the first photosensitive member; and
a second virtual line connecting a rotation center of the third photosensitive member and the rotation center of the fourth photosensitive member is inclined with respect to a first virtual line connecting a rotation center of the first photosensitive member and a rotation center of the second photosensitive member, and an angle made by a rotation axis of the second rotary mirror and the second virtual line being the same as an angle made by a rotation axis of the first rotary mirror and the first virtual line.
Further another object of the present invention is to provide an image forming apparatus including:
a first laser scanner unit for emitting a first laser beam and a second laser beam, which has a first laser source for generating the first laser beam, a second laser source for generating the second laser beam, and a first rotary mirror for deflecting the first laser beam and the second laser beam generated from the first laser source and the second laser source;
a second laser scanner unit for emitting a third laser beam and a fourth laser beam, which has a third laser source for generating the third laser beam, a fourth laser source for generating the fourth laser beam, and a second rotary mirror for deflecting the third laser beam and the fourth laser beam generated from the third laser source and the fourth laser source;
a first photosensitive member irradiated with the first laser beam;
a second photosensitive member irradiated with the second laser beam;
a third photosensitive member irradiated with the third laser beam; and
a fourth photosensitive member irradiated with the fourth laser beam,
characterized in that an angle made by the first laser scanner unit and the second laser scanner unit is equal to an angle made by a first virtual line connecting a rotation center of the first photosensitive member and a rotation center of the second photosensitive member and a second virtual line connecting a rotation center of the third photosensitive member and a rotation center of the fourth photosensitive member.
Further objects of the present invention will become apparent from the following detailed description with reference to the accompanying drawings.
The first embodiment of the present invention will be described with reference to the drawings.
(Image Forming Apparatus)
Further, the image forming apparatus 15 has two scanning optical devices 16 for performing exposure scanning on the four image bearing members (first scanning optical device (first laser scanner unit) 16a and second scanning optical device (second laser scanner unit) 16b). The first scanning optical device 16a and the second scanning optical device 16b are of the same construction. The first scanning optical device 16a applies a light beam to the photosensitive drum 1C (first photosensitive member) and the photosensitive drum 1Y (second photosensitive member), and the second scanning optical device 16b irradiates the photosensitive drum 1M (third photosensitive member) and the photosensitive drum 1K (fourth photosensitive member) with a light beam. The construction of the scanning optical devices 16a and 16b will be described below.
Around the photosensitive drums 1 (1C, 1Y, 1M, and 1K), there are arranged primary chargers 2 (2C, 2Y, 2M, and 2K) for uniformly charging the photosensitive drums 1, developing devices 4 (4C, 4Y, 4M, and 4K) for developing latent images formed on the photosensitive drums 1, transfer rollers 5 (5C, 5Y, 5M, and 5K) for transferring toner images formed on the photosensitive drums 1 to a transfer material 8 conveyed by a transfer belt 7, and cleaners 6 (6C, 6Y, 6M, and 6K) for removing (cleaning) residual toner on the photosensitive drums 1.
In
The image forming operation of the image forming apparatus 15, constructed as described above, will be described. First, the surfaces of the photosensitive drums 1C, 1Y, 1M, and 1K are uniformly charged by the primary chargers 2C, 2Y, 2M, and 2K. Thereafter, light beams (laser beams) 3C, 3Y, 3M, and 3K are emitted from the scanning optical devices 16a and 16b onto the photosensitive drums 1C, 1Y, 1M, and 1K. The light beams 3C, 3Y, 3M, and 3K are optically modulated based on image information, and latent images corresponding to the image information are formed on the surfaces of the photosensitive drums 1C, 1Y, 1M, and 1K irradiated with the laser beams. The latent images are turned into visible images by being supplied with developers (toners) of the respective colors by the developing devices 4C, 4Y, 4M, and 4K, and become cyan, yellow, magenta, and black toner images, respectively.
The transfer materials 8 are stacked on the tray 9. The transfer materials 8 are fed one by one from the tray 9 by the feeding roller 10, and are then sent onto the transfer belt 7 by the registration rollers 11 in synchronism with the writing of the images.
The toner images of the different colors formed on the photosensitive drums 1 are electrostatically attracted to the transfer roller 5 side by a voltage applied to the transfer rollers 5. Here, the transfer material 8 is conveyed on the transfer belt 7 arranged between the transfer rollers 5 and the photosensitive drums 1, so the toner images of the different colors (cyan image, yellow image, magenta image, and black image) are electrostatically transferred to the transfer material 8, and superimposed one upon the other to form a color image. The color image formed on the transfer material 8 is heat-fixed by the fixing device 13. Thereafter, the transfer material 8 is conveyed by the discharging roller 14, etc. to be discharged to the exterior of the image forming apparatus 15.
After this, residual toner remaining on the surfaces of the photosensitive drums 1 is removed by the cleaners 6. Thereafter, to form the next color image, the photosensitive drums 1 are uniformly charged again by the primary chargers 2.
Apart from the full color mode, in which all of the above-described four image forming stations are used, the image forming apparatus of this embodiment has a monochrome mode in which only the black image forming station is used.
As shown in
In this way, in the monochrome mode, the transfer belt 7 of the image forming apparatus of this embodiment is separated from the three photosensitive drums 1C, 1Y, and 1M. In this regard, in the image forming apparatus of this embodiment, in order that the transfer belt 7 may be easily separated from the three photosensitive drums 1C, 1Y, and 1M, the rotation centers of all the photosensitive drums are not arranged in a straight line but the black image photosensitive drum 1K is provided lower than the other photosensitive drums by approximately 1 mm in the vertical direction (direction Z of
In this way, solely the photosensitive drum 1K is provided lower than the other photosensitive drums, thereby, if the lowering amount of the three transfer rollers is small, making it advantageously possible to separate the transfer belt 7 from the three photosensitive drums 1C, 1Y, and 1M.
In this embodiment, the distance between the centers of the black photosensitive drum 1K and the magenta photosensitive drum 1M is the same as the distance between the centers of the yellow photosensitive drum 1Y and the cyan photosensitive drum 1C, and further, is the same as the distance between the centers of the magenta photosensitive drum 1M and the yellow photosensitive drum 1Y. The two light beams 3C and 3Y emitted from the first scanning optical device 16a are parallel to each other. Similarly, the two light beams 3M and 3K emitted from the second scanning optical device 16b are parallel to each other.
(Scanning Optical Device (Laser Scanner Unit))
Mounted in the image forming apparatus of this embodiment is a 2-box type laser scanner unit in which four scanning optical systems corresponding to the four photosensitive members are divided into two laser scanner units.
The scanning optical devices 16a and 16b are provided above the photosensitive drums 1 as shown in
According to the angle θ made by the first virtual line l1 and the second virtual line l2 mentioned above, the first scanning optical device 16a and the second scanning optical device 16b are arranged as follows. That is, they are arranged such that the light beam 3Y (second laser beam) emitted from the first scanning optical device 16a toward the photosensitive drum 1Y (second photosensitive member) and the light beam 3K (fourth laser beam) emitted from the second scanning optical device 16b toward the photosensitive drum 1K (fourth photosensitive member) are at the angle θ. The angle made by the light beam 3C (first laser beam) emitted from the first scanning optical device 16a toward the photosensitive drum 1C (first photosensitive member) and the light beam 3M (third laser beam) emitted from the second scanning optical device 16b toward the photosensitive drum 1M (third photosensitive member) is also θ.
As shown in
As shown in
The light beams 3 (3C and 3Y) scanned by the rotary polygon mirror 20a are transmitted through the scanning lenses 21 (21C and 21Y), and are reflected by the turn-back mirrors 22 (22C and 22Y) in the direction of the photosensitive drums 1 (downward direction of in
As stated above, in this embodiment, when the first virtual line l1 connecting the rotation centers of the photosensitive drums 1C and 1Y and the second virtual line l2 connecting the rotation centers of the photosensitive drums 1M and 1K are at an angle θ, the two scanning optical devices 16a and 16b of the same construction are arranged so as to be inclined with respect to each other according to the angle θ. Then, the positional relationship between the second scanning optical device 16b, the magenta photosensitive drum 1M, and the black photosensitive drum 1K is the same as the positional relationship between the first scanning optical device 16a, the cyan photosensitive drum 1C, and the yellow photosensitive drum 1Y.
With this arrangement, even in the case in which the rotation centers of the photosensitive drums 1C, 1Y, and 1M are arranged in a straight line, and in which the photosensitive drum 1K alone is not provided in the straight line, the respective optical path lengths from the imaging lenses 23 (23C, 23Y, 23M, and 23K) to the photosensitive drums 1 (1C, 1Y, 1M, and 1K) are substantially the same. Thus, the optical path difference is within the scanning optical system lens focal depth, and it is possible to satisfy a predetermined spot diameter.
In this embodiment, the optical path configuration of the third laser beam 3M from the third laser source 19M to the third photosensitive member 1M is substantially the same as the optical path configuration of the first laser beam 3C from the first laser source 19C to the first photosensitive member 1C, and the optical path configuration of the fourth laser beam 3K from the fourth laser source 19K to the fourth photosensitive member 1K is substantially the same as the optical path configuration of the second laser beam 3Y. That is, the third laser beam 3M and the first laser beam 3C are substantially of the same optical path length from the laser source to the photosensitive member, and are substantially of the same reflection angle of the laser beam in the optical path due to the mirror. Further, the fourth laser beam 3K and the second laser beam 3Y are substantially of the same optical path length from the laser source to the photosensitive member, and are substantially of the same reflection angle of the laser beam in the optical path due to the mirror.
In an image forming apparatus which forms a full color image by superimposing toner images of a plurality of colors one upon the other, it is necessary to perform adjustment to suppress scanning line positional deviation, which is a factor of image color drift. In the manufacturing process of the image forming apparatus of this embodiment, the two laser scanner units are mounted to the image forming apparatus main body, and then the lenses 23C, 23Y, 23M, and 23K are shifted in the sub scanning direction to perform irradiation position adjustment for the scanning lines. Although not performed in the image forming apparatus of this embodiment, as other optical adjustment methods, there are also available a method of effecting scanning line irradiation position adjustment by adjusting the angle of the turn-back mirrors 22C, 22Y, 22M, and 22K, and a method of adjusting both those lenses and the mirrors. This scanning line irradiation position adjustment is performed for the purpose of correcting scanning line positional deviation due to the component tolerance of the optical elements, such as the lenses and mirrors, and the optical box, the assembly tolerance at the time of mounting the optical box to the image forming apparatus and at the time of mounting the optical elements to the optical box, etc.; it is an adjustment that must be performed as long as there exists tolerance. For example, its adjustment width is within a range of approximately ±2 mm in the sub scanning direction (drum rotating direction) on the photosensitive drum.
Even when the designing is effected such that the optical path configurations are the same, the optical adjustment for correcting scanning line positional deviation due to tolerance is necessary. Thus, an image forming apparatus in which optical adjustment for correcting scanning line positional deviation due to tolerance has been performed also falls under the category of “substantially of the same optical path configuration”.
Further, in this embodiment, the second virtual line l2 connecting the rotation center of the third photosensitive member 1M and the rotation center of the fourth photosensitive member 1K is inclined with respect to the first virtual line l1 connecting the rotation center of the first photosensitive member 1C and the second photosensitive member 1Y by the angle θ. Further, as shown in
In this way, the optical path configuration of the third laser beam 3M and the optical path configuration of the first laser beam 3C are substantially the same, and the optical path configuration of the fourth laser beam 3K and the optical path configuration of the second laser beam 3Y are substantially the same, and the angle α made by the rotation axis x2 of the second rotary mirror 20b and the second virtual line l2 is the same as the angle α made by the rotation axis x1 of the first rotary mirror 20a and the first virtual line l1, so that if the second virtual line l2 is inclined with respect to the first virtual line l1 by the angle θ, it is possible to make the optical characteristics of the plurality of optical elements mounted in the first laser scanner unit substantially the same as those of the plurality of optical elements mounted in the second laser scanner unit. Thus, making effective use of the advantage of a 2-box type laser scanner unit, it is possible to suppress an increase in the cost of an image forming apparatus. In this embodiment, the optical boxes 17a and 17b are also produced by using the same mold, which further contributes to suppressing an increase in cost. That is, in the case of this embodiment, the two laser scanner units are completely of the same construction.
As shown in
When, as in this embodiment, the angle α made by the rotation axis x2 of the second rotary mirror 20b and the second virtual line l2 is the same as the angle α made by the rotation axis x1 of the first rotary mirror 20a and the first virtual line l1, and the optical path configuration of the first laser beam and the optical path configuration of the third laser beam are substantially the same, and the optical path configuration of the second laser beam and the optical path configuration of the fourth laser beam are substantially the same, the angle made by the first laser beam 3C incident on the first photosensitive member 1C and the third laser beam 3M incident on the third photosensitive member 1M is the same as the angle θ made by the second virtual line l2 and the first virtual line l1. Further, the angle made by the second laser beam 3Y incident on the second photosensitive member 1Y and the fourth laser beam 3K incident on the fourth photosensitive member 1K is also θ.
In this way, the first scanning optical device 16a and the second scanning optical device 16b are of the same construction, so that there is no need to re-design the imaging lenses 23 to match the optical path lengths with each other, and it is possible to produce the scanning optical devices 16 (16a and 16b) by the same production process. This facilitates the production management, making it possible to produce the scanning optical devices at low cost. Further, due to the reduction in the production cost of the scanning optical devices, it is also possible to provide the image forming apparatus at low cost.
Further, since the first scanning optical device 16a and the second scanning optical device 16b are of the same construction, it is possible to minimize the scanning line deviation among the colors. Thus, it is possible to provide a satisfactory image with little color drift.
As stated above, in this embodiment, the optical path configuration of the first laser beam and the optical path configuration of the third laser beam are substantially the same, and the optical path configuration of the second laser beam and the optical path configuration of the fourth laser beam are substantially the same. In this case, as shown in
Further, as stated above, in this embodiment, the second virtual line l2 is inclined with respect to the first virtual line l1 by the angle θ. At the same time, the second laser scanner unit 16b (or the optical box 17b) is also inclined with respect to the first laser scanner unit 16a (or the optical box 17a) by the angle θ. As shown in
While in this embodiment the angle made by the two plates 33a and 33b is θ, it is also possible, as shown in
While in this embodiment the optical path configurations of all the four optical systems are substantially the same as stated above, it is not always necessary for the optical path configuration of the first laser beam 3C and the optical path configuration of the second laser beam 3Y to be substantially the same, and it is not always necessary, either, for the optical path configuration of the third laser beam 3M and the optical path configuration of the fourth laser beam 3K to be substantially the same. Thus, it is not always necessary for the plurality of optical elements forming the optical path for the first laser beam 3C to be of the same optical characteristics as the plurality of optical elements forming the optical path for the second laser beam 3Y, and it is not always necessary, either, for the plurality of optical elements forming the optical path for the third laser beam 3M to be of the same optical characteristics as the plurality of optical elements forming the optical path for the fourth laser beam 3K.
For example, in the image forming apparatuses shown in
Further, it is only necessary for the optical path configuration for the third laser beam 3M and the optical path configuration for the first laser beam 3C to be substantially the same, and for the optical path configuration for the fourth laser beam 3K and the optical path configuration for the second laser beam 3Y to be substantially the same. There is no need for the configuration of the optical box of the first laser scanner unit (first optical box) 17a to be completely the same as the configuration of the optical box of the second laser scanner unit (second optical box) 17b.
For example, in the image forming apparatus shown in
However, from the viewpoint of a reduction in cost, it is very advantageous and desirable for the optical boxes and the optical elements mounted therein to be all substantially of the same construction as in the first laser scanner unit 16a and the second laser scanner unit 16b of this embodiment.
The second embodiment of the present invention will be described with reference to
(Image Forming Apparatus)
As shown in
As in the above-described embodiment, light beams 51C, 51Y, 51M, and 51K emitted from the scanning optical devices 16a and 16b form latent images on the surfaces of photosensitive drums 50C, 50Y, 50M, and 50K. Of the four photosensitive drums, the black and cyan photosensitive drums 50K and 50C at the ends in the vertical direction (Z-direction shown in the figure) of the image forming apparatus 52 are arranged so as to protrude toward a transfer material conveying belt 54 (in the X-direction shown in the figure) by approximately 1 mm with respect to the magenta and yellow photosensitive drums 50M and 50Y.
The transfer material conveying belt 54 attracts a transfer material 53 to its outer peripheral surface on the left-hand side in the figure by electrostatic attraction, and circulates clockwise in the figure in order to bring the transfer material 53 into contact with the photosensitive drums 50C, 50Y, 50M, and 50K. Through the circulation of the transfer material conveying belt 54, the transfer material 53 is conveyed to transfer positions (the positions where it is opposed to the photosensitive drums). Then, toner images on the photosensitive drums 50C, 50Y, 50M, and 50K are transferred to the transfer material 53. When the toner images of the different colors have been successively transferred to the transfer material 53, a color image is formed on the transfer material 53. Then, the color image on the transfer material 53 is heat-fixed by a fixing device 55 before being output to the exterior of the apparatus.
Next, the positional relationship between the photosensitive drums 50, the light beams 51, and the scanning optical device 16 will be described.
The distance between the centers of the black photosensitive drum 50K and the magenta photosensitive drum 50M is the same as the distance between the centers of the yellow photosensitive drum 50Y and the cyan photosensitive drum 50C, and is the same as the distance between the centers of the magenta photosensitive drum 50M and the yellow photosensitive drum 50Y. The two light beams 51C and 51Y emitted from the first scanning optical device 16a are parallel to each other. Similarly, the two light beams 51M and 51K emitted from the second scanning optical device 16b are parallel to each other.
Here, in the image forming apparatus 52, the first virtual line l1 connecting the rotation center of the photosensitive drum 50C and the rotation center of the photosensitive drum 50Y, and the second virtual line l2 connecting the rotation center of the photosensitive drum 50M and the rotation center of the photosensitive drum 50K, are at an angle θ. Further, the second scanning optical device 16b is arranged so as to be inclined with respect to the first scanning optical device 16a according to the angle θ. In this embodiment, the angle θ is approximately 1° (degree). The first scanning optical device 16a and the second scanning optical device 16b are of the same construction.
As in the first embodiment, also in this embodiment, the optical path configuration of the third laser beam 51M and the optical path configuration of the first laser beam 51C are substantially the same, and the optical path configuration of the fourth laser beam 51K and the optical path configuration of the second laser beam 51Y are substantially the same, and the angle α made by the rotation axis x2 of the second rotary mirror 20b and the second virtual line l2 is the same as the angle α made by the rotation axis x1 of the first rotary mirror 20a and the first virtual line l1.
In this embodiment, even in an image forming apparatus having a construction in which, of the four photosensitive drums 50 (50C, 50Y, 50M, and 50K), the photosensitive drums 50C and 50K at the ends in the vertical direction (Z-direction shown in the figure) must protrude in the horizontal direction (in the X-direction shown in the figure), it is possible for the two scanning optical devices 16a and 16b to be substantially of the same construction, making it possible to achieve a reduction in the cost of the image forming apparatus.
However, in this embodiment also, the angle αα made by the rotation axis x2 of the second rotary mirror 20b and the second virtual line l2 is the same as the angle α made by the rotation axis x1 of the first rotary mirror 20a and the first virtual line l1, so that the plurality of optical elements mounted in the first laser scanner unit and the plurality of optical elements mounted in the second laser scanner unit can be substantially of the same optical characteristics. Thus, making effective use of the advantage of a 2-box type laser scanner unit, it is possible to suppress an increase in the cost of an image forming apparatus. Further, as in the first embodiment, it is possible to achieve a further reduction in cost by making the optical box 17a and the optical box 17b of the same construction.
While in the above-described embodiments the colors are arranged in the order: cyan C, yellow Y, magenta M, and black K, this should not be construed restrictively. It is possible to attain the same effect if the colors are arranged in a different order.
It is not always necessary for the two systems of laser beams emitted from one scanning optical device to be parallel to each other; they may also be non-parallel as shown in
Further, as long as the optical components of the scanning optical systems of the two scanning optical devices are the same, the configurations of the components forming the exterior of the scanning optical devices, such as the optical boxes and the optical cover, may be different.
The present invention is not restricted to the above-described embodiments but covers modifications not departing from the technical idea thereof.
This application claims priority based on Japanese Patent Application No. 2004-212857 filed on Jul. 21, 2004 and Japanese Patent Application No. 2005-200465 filed on Jul. 8, 2005, the contents of which are cited herein to constitute a part of the present application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-212857 | Jul 2004 | JP | national |
| 2005-200465 | Jul 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2005/013790 | 7/21/2005 | WO | 00 | 1/31/2006 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2006/009307 | 1/26/2006 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5650253 | Baker et al. | Jul 1997 | A |
| 5916718 | Kellie et al. | Jun 1999 | A |
| 6477348 | Miyamoto et al. | Nov 2002 | B2 |
| 6934497 | Hagiwara et al. | Aug 2005 | B2 |
| Number | Date | Country |
|---|---|---|
| 10-221617 | Aug 1998 | JP |
| 10-228148 | Aug 1998 | JP |
| 2001-42595 | Feb 2001 | JP |
| 2001-209234 | Aug 2001 | JP |
| 2001-337510 | Dec 2001 | JP |
| 2003-159835 | Jun 2003 | JP |
| 2003-211728 | Jul 2003 | JP |
| 2003-279875 | Oct 2003 | JP |
| 2003-337454 | Nov 2003 | JP |
| 03101742 | Dec 2003 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20060290773 A1 | Dec 2006 | US |
