Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
  • G02B26/10—Scanning systems
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
  • G03G15/0142—Structure of complete machines
  • G03G15/0178—Structure of complete machines using more than one reusable electrographic recording member, e.g. one for every monocolour image
  • G03G15/0194—Structure of complete machines using more than one reusable electrographic recording member, e.g. one for every monocolour image primary transfer to the final recording medium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/435—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material
  • B41J2/44—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using single radiation source per colour, e.g. lighting beams or shutter arrangements
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
  • G03G15/0105—Details of unit
  • G03G15/011—Details of unit for exposing
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G2215/00—Apparatus for electrophotographic processes
  • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
  • G03G2215/0103—Plural electrographic recording members
  • G03G2215/0119—Linear arrangement adjacent plural transfer points

Definitions

• Image forming apparatus having a plurality of laser scanner units
• tandem type image forming apparatus has the advantage that there are relatively many recording media available and high recording speed, and is becoming the main form of color image forming apparatuses in recent years.
• Japanese Patent Application Laid-Open Nos. 200-23795 and 10-21267 have been proposed for four photosensitive members.
• Two scanners (2 B OX type) are listed.
• Each of the laser scanners mounted in this type of image forming apparatus has one polygon mirror (shared) for two optical systems, and the image forming apparatus can be miniaturized and It is effective in cost reduction. ⁇
• Japanese Patent Application Laid-Open No. 200-145 discloses a configuration in which the second and third photosensitive members out of the first to fourth photosensitive members protrude about 1 mm to the transfer belt side. It is done.
• the transfer belt for carrying and conveying the recording paper is in contact with all four photosensitive members in full-color printing, but in monochrome printing, the three photosensitive members other than the black photosensitive member are used.
• the transfer belt separates from the body.
• the transfer belts to the respective photosensitive members at the time of full color printing are Since the recording paper carrying surface of the transfer belt is flat during monochrome printing while keeping the contact state of the belt properly, it is possible to suppress peeling of the recording paper from the transfer belt.
• the laser scanner unit corresponding to four photosensitive members is divided into four (4 BOX type), so the distance between the second and third photosensitive members protruding to the transfer belt side If the second and third laser scanner units of the same configuration and the same distance as (in this case, l mm) are shifted parallel to the transfer belt side, an optically appropriate layout can be obtained.
• the imaging lenses 101 and 102 have the same optical characteristics to ensure uniform imaging on each photosensitive drum, but the imaging lenses 100 and 103 have different optical characteristics. There is. Therefore, the two laser scanner units 200 and 201 have different configurations, and the cost advantage of the 2 B O X type is lost due to the different configurations. Disclosure of the invention
• the present invention has been made in view of the above-described problems, and an object thereof is to provide an image forming apparatus whose cost can be reduced.
• Another object of the present invention is to provide an optical element mounted on the first laser scanner unit and an optical element mounted on the second laser scanner unit with the same optical characteristics.
• Another object of the present invention is
• a first laser scanner unit for emitting first and second laser beams; a first light source for generating the first laser beam; and a second light source for generating the second laser beam
• a first laser scanner comprising: a light source; and a first rotating mirror for deflecting the first and second laser beams generated from the first and second light sources;
• a third light source for generating the third laser beam and a fourth light source for generating the fourth laser beam
• a second laser scanner having a second rotating mirror for deflecting the third and fourth laser beams generated from the third and fourth light sources;
• a third photosensitive member irradiated with the third laser beam
• the optical path shape of the third laser beam from the third light source to the third photosensitive member is substantially the same as the optical path shape of the first laser beam from the first light source to the first photosensitive member.
• the optical path shape of the fourth laser beam from the fourth light source to the fourth photosensitive member is the optical path shape of the fourth laser beam from the second light source to the second photosensitive member While being almost identical
• the second virtual line connecting the rotation center of the third photosensitive member and the rotation center of the fourth photosensitive member is the rotation center of the first photosensitive member and the rotation center of the second photosensitive member.
• an angle formed by the rotation axis of the second rotating mirror and the second virtual line is the rotation axis of the first rotating mirror and the first virtual line. Equal to the angle of the line
• Another object of the present invention is
• a first laser scanner unit that emits first and second laser beams; a first light source generated by the first laser and a second laser beam generated by the second laser beam;
• a first laser scanner comprising: a light source; and a 1 'rotating mirror for deflecting the first and second laser beams generated from the first and second light sources;
• a first photosensitive member irradiated with the first laser beam
• a second photosensitive member irradiated with the second laser light
• a third photosensitive member irradiated with the third laser beam
• a fourth photosensitive member irradiated with the fourth laser beam
• the optical path shape of the third laser beam from the third light source to the third photosensitive member is as follows: the optical path shape of the second laser beam from the second light source to the second photosensitive member Almost identical,
• the optical path shape of the fourth laser beam from the fourth light source to the fourth photosensitive member is the first laser beam from the first light source to the first photosensitive member Substantially the same as the optical path shape of
• a second virtual line connecting the rotation center of the third photosensitive member and the rotation center of the fourth photosensitive member connects the rotation center of the first photosensitive member and the rotation center of the second photosensitive member.
• the first virtual line is inclined with respect to the first virtual line, and the angle between the second virtual line and the rotation axis of the second rotating mirror is equal to the rotation axis of the first rotating mirror and the first virtual line. Equal to the corner.
• An object of the present invention is to provide an image forming apparatus characterized in that.
• Another object of the present invention is
• a first laser scanner unit emitting first and second laser beams, the first light source generating the first laser beam, and the second light source generating the second laser beam
• a first laser scanner having a first rotating mirror for deflecting the first and second laser beams generated from the first and second light sources;
• a second laser scanner unit for emitting third and fourth laser beams, a third light source for generating the third laser beam, and a fourth light source for generating the fourth laser beam
• a second laser scanner having: second and third mirrors for deflecting the third and fourth laser beams generated from the third and fourth light sources;-the first laser beam; A first photoreceptor to be illuminated;
• a second photosensitive member irradiated with the second laser light
• a third photosensitive member irradiated with the third laser beam
• a fourth photosensitive member irradiated with the fourth laser light
• a first angle between the first laser scanner unit and the second laser scanner unit connects the rotation center of the first photosensitive member to the rotation center of the second photosensitive member.
• the virtual line and the center of rotation of the third photosensitive member It is an object of the present invention to provide an image forming apparatus characterized by being equal to an angle formed by a second imaginary line connecting the rotation centers of the fourth photosensitive member.
• FIG. 1 is a simplified sectional view of an image forming apparatus according to a first embodiment of the present invention.
• FIG. 2 is an internal structural view of a laser scanner bench mounted on the image forming apparatus of the first embodiment.
• FIG. 3 is a simplified cross-sectional view of an image forming apparatus according to a second embodiment of the present invention.
• FIG. 4 is a simplified cross-sectional view of an image forming apparatus of a comparative example for understanding the present invention.
• FIG. 5 is a cross-sectional view showing the transfer belt in contact with all four photosensitive drums. '
• FIG. 6 is a cross-sectional view showing the transfer belt separated from the three photosensitive drums 1 C, 1 Y, and 1 Y.
• FIG. 7 is a perspective view of the image forming apparatus of the first embodiment. '
• FIG. 8 is a perspective view showing the mounting state of the laser scanner kit mounted on the image forming apparatus of the first embodiment.
• FIG. 9 is a perspective view showing a modification of the attachment state of the laser scanner unit.
• FIG. 10 is a simplified cross-sectional view of an image forming apparatus ′ according to a modification of the first embodiment. .
• FIG. 11 is a simplified cross-sectional view of an image forming apparatus according to a modification of the first embodiment.
• FIG. 12 is a simplified cross-sectional view of an image forming apparatus according to a modification of the first embodiment.
• FIG. 13 is a simplified sectional view of an image forming apparatus according to a third embodiment of the present invention.
• FIG. 14 is a perspective view of an image forming apparatus according to a third embodiment. BEST MODE FOR CARRYING OUT THE INVENTION First embodiment ''.
• FIG. 1 is an explanatory view of an image forming apparatus according to the first embodiment. First, after describing the entire image forming apparatus, the configuration of a scanning optical apparatus (laser scanner unit) will be described.
• a scanning optical apparatus laser scanner unit
• FIG. 1 is a view showing an image forming apparatus 15 according to an embodiment of the present invention.
• the image forming apparatus 15 is capable of forming a color image by superimposing toner images on four colors (cyan C, yellow Y, magenta ⁇ , black) and has four image forming stations. Each image forming station The first image carrier (photosensitive drum 1 C), the second image carrier (photosensitive drum 1 Y), the third image carrier (photosensitive drum 1 M), the fourth image carrier (photosensitive Have a body drum 1 K).
• the image forming apparatus 15 includes: two scanning optical devices 16 (first scanning optical device (first laser scanner unit) 16a for performing exposure scanning on the four image carriers; second scanning optical device (second Laser scanner unit 16 b).
• the first scanning optical device 16a and the second scanning light ⁇ device 16b have the same configuration, and the first traveling optical device 16a is a photosensitive drum 1 C (first photosensitive member) and a photosensitive member
• the second scanning optical device 16b irradiates the drum 1 Y (second photosensitive member) with a light beam, and the second scanning optical device 16b applies the photosensitive drum 1M (third photosensitive member) and the photosensitive drum 1 K (fourth photosensitive member) I irradiate a luminous flux.
• a tray 9 for loading and storing the transfer material 8 for loading and storing the transfer material 8
• a feed roller 10 for feeding the transfer material 8 one by one from the tray 9, and the transfer material 8 fed out.
• a registration roller 11 for conveying in synchronism with the timing of image formation, a transfer belt 7 in contact with the four photosensitive drums 1 and conveying the transfer material 8 to the respective photosensitive drums in order; Have.
• the transfer belt 7 is stretched by a drive roller 12 and a tension roller 30.
• the drive roller 12 feeds the transfer belt 7 with high accuracy, and is connected to a drive motor (not shown) with small rotational unevenness.
• a fixing device 13 for fixing the toner image to the transfer material 8 by heating, pressure or the like, and the transfer material 8 after image formation A discharge roller 14 is provided to discharge to the outside.
• the image forming operation of the image forming apparatus 15 will be described.
• the photosensitive drums 1 C, 1 Y, 1 ⁇ , and 1 ⁇ are uniformly charged by the primary chargers 2 C, 2 Y, 2 ⁇ , and 2 ⁇ .
• a light beam (laser beam) 3 C, 3 Y, 3 ⁇ , 3 ⁇ is emitted from the scanning optical device 16 a, 16 b with respect to the photosensitive drum 1 C, 1 Y, 1 ⁇ , I K.
• the luminous fluxes 3 C, 3 Y, 3 ⁇ and 3 ⁇ are respectively light modulated based on the image information, and the image information on the surface of the irradiated photosensitive drums 1 C, 1 Y, 1 M and IK Forms a latent image according to
• the latent images are visualized by supplying developers (toners) of respective colors by developers 4 C, 4 Y, 4 ⁇ , 4 ⁇ , and cyan, yellow, magenta, and black toners, respectively. It becomes an image.
• the transfer material 8 is stacked on the tray 9.
• the transfer material 8 is sequentially fed one by one from the tray 9 by the feed roller 10, and then sent out onto the transfer belt 7 by the resist roller 11 in synchronization with the image writing timing.
• the toner image of each color formed on the photosensitive drum 1 is applied to the transfer roller 5. It is electrostatically attracted to the transfer roller 5 by the voltage applied.
• the transfer material 8 since the transfer material 8 is conveyed on the transfer belt 7 disposed between the transfer roller 5 and the photosensitive drum 1, the toner images of the respective colors (cyan image, yellow image, The magenta image and the black image) are electrostatically transferred onto the transfer material 8 and sequentially superimposed to form a color image.
• the color image formed on the transfer material 8 is thermally fixed by the fixing device 13. Thereafter, the transfer material 8 is conveyed by the discharge roller 14 or the like and discharged out of the image forming apparatus 15.
• the residual toner J remaining on the surface of the photosensitive drum 1 is removed by the cleaner 6. Thereafter, the photosensitive drum 1 is subjected to the primary charging to form the next color image. It is uniformly charged again by 2.
• the image forming apparatus of the present embodiment has a monochrome mode using only the black image forming station, in addition to the full color mode using all the four image forming stations described above.
• FIG. 5 shows the state of the transfer belt 7 in the full color mode
• FIG. 6 shows the state of the transfer belt 7 in the monochrome mode.
• Three transfer rollers 5C, 5Y, and 5. In the present embodiment, the direction in which the transfer belt 7 is brought into contact with the photosensitive drum 1C, and the direction in which the transfer belt 7 contacts the photosensitive drums 1C, 1Y, and 5.
• the transfer roller 5 K can move in a direction away from one side (the transfer roller 5 K does not move) When performing image formation in the full color mode, as shown in FIG.
• Three transfer rollers 5 C, 5 Y, and 5 ⁇ ⁇ push up the transfer belt 7 so that 1 C, 1 Y, 1 ⁇ , and 1 ⁇ contact all, while forming an image in monochrome (black and white) mode
• the transfer belt 7 is not in contact with the three photosensitive drums 1C, 1Y, and 1C, except for the transfer rollers 5C, 5Y, and 5B.
• the image forming apparatus of this embodiment has three photosensitive drums 1 C and 1 C in the monochrome mode. Y and 1 M 'are stopped without rotation, and these photosensitive drums are not used.
• the transfer roller is used to suppress the decrease in the life of the photosensitive drums 1 C, 1 Y, and 1 ⁇ ⁇ ⁇ due to rubbing against the non-rotating photosensitive drums 1 C, 1 Y, and 1 ⁇ .
• the downward movement of 5C, 5Y, and 5 ⁇ ⁇ ⁇ prevents the transfer belt 7 from contacting the three photosensitive drums 1C, 1Y, and 1 ⁇ .
• the transfer roller 5 K for black does not move because it is at the same position in both the full color mode and the monok opening mode.
• the transfer belt 7 is configured to be separated from the three photosensitive drums 1 C, 1 Y, and 1 ⁇ in the monochrome mode. Therefore, in the image forming apparatus 1 of this embodiment, the rotational centers of all the photosensitive drums are on a straight line so that the transfer belt 7 can be easily separated from the three photosensitive drums 1C, 1Y, and 1 ⁇ .
• the photosensitive drum 1 K of the black image is not disposed about 1 mm below the other photosensitive drums in the vertical direction (the Z direction in FIG. 1).
• a straight line connecting the rotation center of the photosensitive drum 1 C (first photosensitive member) and the rotation center of the photosensitive drum 1 Y (second photosensitive member) is a first virtual line
• the photosensitive drum 1 M Assuming that a straight line connecting the rotation center of the (third photosensitive member) and the rotation center of the photosensitive drum 1 (the fourth photosensitive member) is a second imaginary line £ 2, the first imaginary line ⁇ and the second imaginary line
• the line ⁇ 2 is disposed at an angle ((the second imaginary line ⁇ 2 is inclined to the first imaginary line ⁇ 1).
• the rotational centers of the three photosensitive drums 1C, 1Y, and 1 ⁇ are arranged in the same straight line.
• the four photosensitive drums have the same diameter.
• the three transfer rollers 5C, 5Y, and 5C may have three photosensitive members, even if the drop amount is small. There is a merit that the transfer belt 7 can be separated from the body drums 1 C, 1 Y, 1 ⁇ .
• the distance between the centers of the photosensitive drum 1 K for black and the photosensitive drum 1 M for magenta is the sense of yellow for photosensitive drum 1 Y and cyan.
• the distance between the centers of the light drum 1C is the same, and the distance between the centers of the photosensitive drum 1M for magenta and the photosensitive drum 1Y for yellow is also the same.
• the two light beams 3 C and 3 Y emitted from the first scanning optical device 16 a are parallel.
• the two light beams 3 M and 3 K emitted from the second scanning optical device 16 b are parallel.
• the image forming apparatus of the present embodiment is equipped with a 2-BOX type laser scanner in which four scanning optical systems corresponding to four photosensitive members are divided into two laser scanner sets.
• the scanning optical devices 16a and 16b are provided above the photosensitive drum 1 in FIG.
• the first scanning optical device 16a first laser scanner unit
• the second scanning optical device 16b second laser scanner unit
• first scanning optical device 16a and the second scanning optical device 16b are disposed as follows according to the angle ⁇ ⁇ formed by the first virtual line ⁇ and the second virtual line ⁇ 2 described above. . That is, a light beam 3Y (second laser beam) emitted from the first scanning optical device 16a to the photosensitive drum 1Y (second photosensitive member) and the photosensitive drum 1 from the second scanning optical device 16b.
• a luminous flux 3 K (fourth laser light) emitted toward K (fourth photosensitive member) is disposed to have an angle ⁇ .
• the angle formed by the luminous flux 3M (third laser beam) emitted toward the (third photoreceptor) is also known.
• the distance between the second scanning optical device 16b and the position where the light beam 3 K of the second scanning optical device 16b emerges (the surface of the laser light of the lens 23 K) is set to be the same (both are distance ml).
• the luminous flux 3 C and the luminous flux 3 Y are parallel, and the luminous flux 3 M and the luminous flux 3 K are also parallel.
• the luminous flux 3 C and the luminous flux 3 Y do not necessarily have to be parallel.
• the angle ⁇ ⁇ in the present embodiment is about 1 °.
• FIG. 2 is a top view of the scanning optical device 16a.
• the second scanning optical device 16b has the same internal configuration as the first scanning optical device 16a, the description of the second scanning optical device 16b will be omitted.
• luminous fluxes emitted from the semiconductor laser 19 (the first light source 19C, the second light source 19Y) as the light source corresponding to the image information of each color (cyan and yellow) (the first The laser light 3 C and the second laser light 3 Y) are scanned in different directions corresponding to the respective colors by the rotary polygon mirror (first rotary mirror) 20 a disposed at the center.
• the rotary polygon mirror 20a is rotationally driven by a drive motor (optical deflector).
• optical components such as a substrate 20A on which a drive motor is mounted, a scanning lens (f lens) 21 and a folding mirror 22 are enclosed in an optical box 17a. Be done.
• the upper opening of the optical box 17a is closed by the optical rod 18a.
• the optical box 1 7a and the optical box 1 7b of the present embodiment are made of resin molded using the same mold.
• Rotary polygon mirror 20a the light beam 3 which is scanned by (3 C, 3 Y) passes through the respective scanning lenses 21 (21C, 21Y), photoreceptor de by folding mirror 22 (22C, 22Y); a ram one direction It is reflected (downward in Fig. 1).
• the luminous flux 3 (3 C, 3 Y) passes through the imaging lens 23 (23 C, 23 Y) as shown in FIG. 1 and exits from the first sliding optical device 16 a.
• the light beam 3 forms an image on the photosensitive drums 1C and 1Y.
• the central distance between the imaging lens 23C and the imaging lens 23Y is: photosensitive drum 1C and photosensitive drum 1 It is the same as the distance to Y.
• the first virtual line ⁇ 1 connecting the rotational centers of the photosensitive drums 1 C and 1 Y and the second virtual line ⁇ connecting the rotational centers of the photosensitive drums 1 and 1 If 2 has an angle ⁇ , two scanning optical devices 16a, 16b of the same configuration are arranged in an inclined manner according to this angle ⁇ . Then, the relative positional relationship between the second scanning optical device 16b, the photosensitive drum 1M of magenta and the photosensitive drum 1K of black is the first scanning optical device 16a, and the photosensitive drum 1C of cyan. The relative positional relationship between the photosensitive drum 1 Y and the photosensitive drum 1 is the same.
• the rotation centers of the photosensitive drums 1 C, 1 Y, and 1 ⁇ are disposed on a straight line, and even if only the photosensitive drum 1 K is not disposed on the straight line,
• the optical path lengths from each imaging lens 23 (23C, 23Y, 23 ⁇ , 23 ⁇ ) to the photosensitive drum 1 (1C, 1Y, 1M, IK) are substantially the same. For this reason, the optical path difference can be accommodated within the focal depth of the sliding optical system lens, and the predetermined spot diameter can be satisfied.
• the optical path shape of the third laser light 3 M from the third light source 19 M to the third photoreceptor 1 M is the first light source 19 C to the first photoreceptor.
• the optical path shape of the first laser beam 3 C up to 1 C is substantially the same, and the optical path shape of the fourth laser beam 3 K from the fourth light source 1 9 K to the fourth photosensitive member 1 K is the fourth
• the optical path shape of the 2 laser beam 3 Y is substantially the same. That is, the third laser beam 3M and the first laser beam 3C both have substantially the same optical path length from the light source to the photosensitive member, and the reflection angle of the laser beam in the optical path by the mirror is also substantially the same.
• the optical path lengths from the light source to the photosensitive member of the fourth laser light 3K and the second laser light 3Y are also substantially equal, and the reflection angles of the laser light in the optical path by the mirrors are also approximately equal.
• the irradiation position of the scanning line is adjusted by shifting 2 3 K in the sub-scanning direction.
• the angles of the folding mirrors 2 2 C, 2 2 Y, 2 2 ⁇ , 2 2 ⁇ are adjusted to adjust the scanning line.
• Such irradiation position adjustment of the scanning line is based on tolerances of optical elements such as lenses and mirrors and parts of the optical box, assembly tolerances when the optical box is attached to the image forming apparatus, and optical elements are attached to the optical box. This is done to correct the misalignment of the scanning line, and it is necessary adjustment as long as tolerance exists.
• the adjustment range is within a range of about ⁇ 2 mm in the side running direction (the drum rotation direction) on the photosensitive drum.
• optical path shape is substantially the same.
• the second virtual line ⁇ 2 connecting the rotation center of the third photosensitive member 1 M and the rotation center of the fourth photosensitive member 1 K is the rotation center of the first photosensitive member 1 C and It is inclined at an angle ⁇ to a first imaginary line ⁇ ⁇ ⁇ connecting the rotation centers of the second photoreceptor 1 ⁇ .
• the angle ⁇ between the rotation axis X 2 of the second rotating mirror 20 b and the second virtual line ⁇ 2 is the rotation axis x 1 of the first rotating mirror 20 a. It is equal to the angle between the first virtual line ⁇ and the first imaginary line.
• the optical path shape of the third laser light 3 and the optical path shape of the first laser light 3 C are substantially the same, and the optical path shape of the fourth laser light 3 C and the second laser light
• the optical path shape of the third lens is substantially the same, and the angle ⁇ between the rotation axis X 2 of the second rotary mirror 20 b and the second virtual line ⁇ 2 is the rotation axis of the first rotary mirror 20 a Since it is equal to the angle ⁇ between x 1 and the first virtual line ⁇ 1, the second virtual line ⁇ 2 is the first virtual line Even if the line e is inclined at an angle e, the plurality of optical elements mounted on the first laser scanner unit and the plurality of optical elements mounted on the second laser scanner unit are optically substantially the same. It can be of the characteristic. Accordingly, the merit of the 2BOX type laser scanner unit can be utilized to reduce the cost of the image forming apparatus. In the case of this embodiment, since the optical boxes 17 a and 17 b are also manufactured using the same mold, the cost can be further suppressed. That is, in the case of the present embodiment, the two laser scanner units have completely the same configuration.
• the direction of the first laser beam 3 C from the first rotary mirror 20 a to the first photosensitive member 1. C, and the first rotary mirror The direction of the second laser light 3 Y from 2 0 a to the second photosensitive member 1 Y is opposite, but the optical paths of the two systems have substantially the same optical path length from the light source to the photosensitive member, and Rays: The reflection angles of the lights are also approximately equal, so in this case the optical path shapes can be considered identical.
• the angle between the rotation axis X2 of the second rotary mirror 20 b and the second virtual line ⁇ 2 is the rotation axis X 1 of the first rotary mirror 20 a and the rotation axis X 1 of the first rotary mirror 20 a.
• the optical path shape of the first laser beam and the optical path shape of the third laser beam are substantially the same, and the optical path of the second laser beam is equal to the angle ⁇ formed by the first virtual line ⁇ 1.
• the shape and the optical path shape of the fourth laser light are substantially the same, as shown in FIG. 1, the first laser light 3 C and the third photoconductor 1 c entering the first photoconductor 1 C
• the angle formed between the second virtual line ⁇ 2 and the first virtual line ⁇ 1 is equal to 0.
• the angle between the second laser beam 3 incident on the second photosensitive member 1 Y and the fourth laser beam 3 incident on the fourth photosensitive member 1 is also zero.
• first scanning optical device 16a and the second scanning optical device 16b have the same configuration, it is possible to extremely reduce the scanning line deviation between the respective colors. Therefore, it is possible to provide a good image with little color shift.
• FIG. 7 is a perspective view of the image forming apparatus according to the present embodiment, in which the exterior cover of the image forming apparatus and a part of the optical box are shown so as to expose the insides of the two laser scanner sets.
• FIG. 7 is a perspective view of the image forming apparatus according to the present embodiment, in which the exterior cover of the image forming apparatus and a part of the optical box are shown so as to expose the insides of the two laser scanner sets.
• the optical path shape of the first laser beam and the optical path shape of the third laser beam are substantially the same, and the optical path shape of the second laser beam and the fourth laser beam
• the optical path shapes are substantially the same.
• two light sources 1 9 C and 1 9 Y mounted on the first laser scanner unit and two light sources mounted on the second laser scanner unit 1 9 M And 1 9 K are laid out on the same side 70 (REAR SIDE in this embodiment) of the image forming apparatus main body. In this way, if all four light sources are laid out on the same side, it is easy to put together the electrical wiring around the drive circuit board on which the light sources (semiconductor lasers) are mounted, and it is easy to assemble the device. There is.
• the second virtual line ⁇ 2 is inclined at an angle of 0 with respect to the first virtual line ⁇ 1, but the second laser scanner unit 16 b (or the optical box 1 7) b) is also inclined at an angle to the first laser scanner unit 16 a (or optical box 17 a).
• the second laser scanner unit 16b is first In this embodiment, as shown in FIG. 8, in order to make an angle with the laser scanner unit 16a, as shown in FIG. 8, a plate 33b for positioning and holding the second laser scanner unit 16b (second holding member ) Is inclined at an angle to the plate 3 3 a (first holding member) for positioning and mounting the first laser scanner unit 1 6 a.
• the first laser scanner unit 16a is attached to the plate 33a with a screw 32a
• the second laser scanner unit 16b is attached to the plate 33b with a screw 32b. It is done.
• the angle formed by the two plates 33 a and 33 b is ⁇ , but as shown in FIG. 9, two laser scanner units are positioned on one plate (holding member). Two holes (positioning parts) are provided (this plate is provided one by one in FRONT SIDE and REAR SIDE of the main body of the image forming apparatus), and the angle formed by these holes may be used as ⁇ .
• the laser scanner unit is positioned at two sides intersecting each other among the four sides forming the rectangular positioning hole. In short, it is sufficient to set the angle formed by the parts for determining the position of each laser scanner unit.
• the plates installed in the FR0NT SIDE and REAR SIDE of the image forming apparatus main body are preferably made of sheet metal processed using the same press. This is because the positioning accuracy of the laser scanner unit is improved by processing these two plates having the positioning holes using the same press.
• the optical path shapes of the four systems of optical systems are all substantially the same, the optical path shape of the first laser beam 3 C and the optical path shape of the second laser beam 3 Y Are not necessarily substantially the same, and the shape of the optical path of the third laser beam 3 M and the shape of the optical path of the fourth laser beam 3 K do not necessarily have to be substantially the same. Therefore, the optical characteristics of the plurality of optical elements forming the optical path of the first laser beam 3 C and the plurality of optical elements forming the optical path of the second laser beam 3 Y are necessarily determined. It is not necessary that they are substantially identical, and a plurality of optical paths of the third laser beam 3 M are formed. The optical properties of the optical element and the plurality of optical elements forming the optical path of the fourth laser beam 3 K need not necessarily be substantially the same.
• the optical path shape of the third laser light 3 M and the optical path shape of the first laser light 3 C are substantially the same.
• the optical path shape of the third laser light 3 M and the optical path shape of the fourth laser light 3 K are not substantially the same.
• the optical path shape of the third laser beam 3 M and the optical path shape of the first laser beam 3 C are substantially the same, and the fourth laser beam 3
• the optical path shape of K and the optical path shape of the second laser beam 3 Y are substantially the same, and the angle ⁇ between the rotation axis X 2 of the second rotating mirror 20 b and the second virtual line ⁇ 2 is the second
• the first laser scanner unit and the second laser scanner unit have substantially the same configuration, which is equal to the angle ⁇ between the rotation axis x 1 of the first rotating mirror 20 a and the first virtual line ⁇ 1. This is an example that can be done.
• the optical path shape of the third laser beam 3 and the optical path shape of the first laser beam 3 C are substantially the same, and the optical path shape of the fourth laser beam 3 C and the optical path shape of the second laser beam 3 C
• the first laser scanner unit's optical box (first optical box) 17 a and the second laser scanner unit's optical box (second optical box) 17 The shape of b need not be identical.
• the optical path shapes of the four systems of laser beams 3 M to 3 K are all substantially the same, but the shapes of the optical box 1 a and the optical box 17 b are It is different from midday. Specifically, the shapes of the optical box near the mirror 2 2 Y and the mirror 2 2 K are different from each other. Due to this difference in shape, the thickness of the mirror 2 2 K 2 is thinner than the thickness t 1 of the other three mirrors 2 2 C, 2 2 Y, and 2 2 ⁇ . However, only the thicknesses of the mirror 22 K and the other mirrors 22 C, 22 Y, and 22 ⁇ ⁇ ⁇ are different, and the optical characteristics are substantially the same.
• the optical path shape of the third laser beam 3 M and the optical path shape of the first laser beam 3 C are substantially the same, and the optical path shape of the fourth laser beam 3 K and the second The shape of the optical path of the laser beam 3 Y is substantially the same, and the angle ct between the rotation axis X 2 of the second rotating mirror 20 b and the second virtual line ⁇ 2 is the first rotating mirror 20
• a plurality of optical elements (mirror 1 2 2 C) mounted on the first laser scanner unit and the second laser scanner unit are equal to the angle ct formed by the rotation axis x 1 of a and the first virtual line ct. This is an example in which ⁇ 2 2 K and 2 3 C ⁇ 2 3 K) can be made to have substantially the same configuration.
• the optical box and the optical elements mounted in the same are all of the same configuration. It is very advantageous and preferable for cost reduction.
• FIG. 3 is an explanatory view of an image forming apparatus according to a second embodiment.
• the explanation of the same configuration as the above is omitted.
• the image forming apparatus 52 of the present embodiment includes the first scanning optical device 16a and the second scanning optical device 16b described above.
• the light beams 51C, 51Y, 51M, 51K emitted from the scanning optical devices 16a, 16b form latent images on the surfaces of the photosensitive drums 50C, 50Y, 50 ⁇ , 50 ⁇ .
• the black and cyan photosensitive drums 50 and 50 C at both ends of the image forming apparatus 52 in the vertical direction correspond to the magenta and yellow photosensitive drums 50 and 50.
• the transfer material conveying belt 54 is disposed so as to protrude on the side of the transfer material conveying belt 54 (X direction in the drawing) by about mm.
• the transfer material conveying belt 54 is a transfer material by electrostatic attraction on the outer peripheral surface on the left side in the drawing.
• the transfer material 53 is circulated clockwise in the figure so as to bring the transfer material 53 into contact with the photosensitive drums 50C, 50Y, 50 ⁇ , 50 ⁇ .
• the transfer movement of the transfer material conveying belt 54 conveys the transfer material 53 to the transfer position (a position facing the respective photosensitive drums).
• toner images of the respective photosensitive drums 50 C, 50 Y, 50 ⁇ m, and 50 ⁇ m are transferred to the transfer material 53.
• a toner image of each color is sequentially transferred onto the transfer material 53, a color image is formed on the transfer material 53.
• the color image on the transfer material 53 is thermally fixed by the fixing device 55, and then output to the outside of the apparatus.
• the distance between the centers of the black photosensitive drum 50 ⁇ ⁇ ⁇ and the magenta photosensitive drum 50 ⁇ is the same as the distance between the centers of the yellow photosensitive drum 50 ⁇ and the cyan photosensitive drum 50C, and the magenta photosensitive drum 50 0 It is the same as the center-to-center distance between the yellow and yellow photoreceptor drums 50.
• the two light beams 51C and 51Y emitted from the first scanning optical device 16a are parallel.
• the two light beams 51M and 51K emitted from the second scanning optical device 16b are parallel.
• the image forming apparatus 52 is a first virtual line ⁇ connecting the rotation center of the photosensitive drum 50C and the rotation center of 50Y, the rotation center of the photosensitive drum 50 ⁇ and the rotation center of the photosensitive drum 50 ⁇ . And a second virtual line ⁇ 2 connecting them with an angle ⁇ .
• the second scanning optical device 16b is disposed to be inclined according to the angle ⁇ ⁇ ⁇ with respect to the first scanning optical device 16a. In the case of this embodiment, the angle ⁇ is approximately 1 °. Further, the first scanning optical device 16a and the second scanning optical device 16b have the same configuration.
• the optical path shape of the third laser beam 51 M and the optical path shape of the first laser beam 51 C are substantially the same as in the first embodiment, and the optical beam shape of ⁇ 4
• the path shape and the optical path shape of the second laser beam 5 1 Y are substantially the same, and the second time
• the angle ⁇ between the rotation axis X 2 of the turning mirror 20 b and the second virtual line ⁇ 2 is the angle ⁇ between the rotation axis X 1 of the first rotating mirror 20 + a and the first virtual line ⁇ ⁇ It is equal.
• the photosensitive drums 50C and 50K at both ends in the vertical direction ( ⁇ direction in the figure) are in the horizontal direction (in the figure Even in the case of an image forming apparatus having a configuration in which it is necessary to project and arrange in the X direction), the configurations of the two scanning optical devices 16a and 16b can be made substantially the same, thereby reducing the cost of the image forming apparatus. I can do it.
• FIGS. 1.3 and 14 show a third embodiment.
• the optical path shape of the first laser beam and the optical path shape of the third laser beam are substantially the same, and the optical path shape of the second laser beam and the fourth laser beam The optical path shape was almost the same.
• the optical path shape of the first laser beam and the optical path shape of the fourth laser beam are substantially the same, and the optical path shape of the second laser beam and the optical path shape of the third laser beam are substantially It is the same. In such a case, as shown in FIG.
• two light sources 1 SC and 1 9 Y mounted on the first laser scanner unit 1 6 a are one side of the image forming apparatus (this embodiment)
• two light sources 1 9 M and 1 9 K mounted on the second laser scanner unit 1 6 b are laid out on the other side (REAR SIDE in this embodiment). Be done.
• an angle ⁇ between the rotation axis X2 of the second rotating mirror 20b and the second virtual line ⁇ 2 is the rotation axis x1 of the first rotating mirror 20a and the first Since it is equal to the angle formed by the virtual line ⁇ 1, the plurality of optical elements mounted on the first laser scanner unit and the plurality of optical elements mounted on the second laser scanner unit are optically approximately formed. You will meet the same characteristics. Therefore, it is possible to reduce the cost of the image forming apparatus by making use of the merit of the two-type laser scanner unit. Also, as in the first embodiment, the optical box 1 a a and the optical box 1 7 b The cost can be further reduced if the same configuration is used.
• the arrangement of each color is arranged in the order of cyan C, yellow Y, magenta ⁇ , black ⁇ , but not limited to this, the same effect can be obtained by arranging in different order .
• the two scanning optical devices may have different shapes of components forming the outside of the scanning optical device, such as an optical box and an optical lid, as long as the optical components of the scanning optical system are the same.
• the present invention is not limited to the examples described above, but includes variations within the technical concept.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Mechanical Optical Scanning Systems (AREA)
• Color Electrophotography (AREA)
• Facsimile Heads (AREA)
• Laser Beam Printer (AREA)
• Exposure Or Original Feeding In Electrophotography (AREA)

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• 2005
  • 2005-07-08 JP JP2005200465A patent/JP4557825B2/ja not_active Expired - Fee Related
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