JP2008076586A - Scanning optical device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning optical device and an image forming device, capable of reducing color slurring by arranging direction of variation in irradiation position of each luminous flux on a photoreceptor caused by thermal deformation of each light source holding member generated by heat generation of each light source. <P>SOLUTION: To a housing member 30 containing: two or more semiconductor lasers 10Y to 10K; light source holding members for holding the semiconductor lasers; fixing members for fixation by energizing; a deflection scanning means 20 for performing deflection scanning with the luminous fluxes emitted from the semiconductor lasers; and two or more scanning optical systems which are located on the same side or both sides to a rotating shaft of the deflection scanning means 20 and perform scanning on the respective photoreceptors with each deflection-scanned luminous flux; in the scanning optical device S1 in which luminous fluxes reflected by two or more reflecting mirrors 26 exist, the positions of the two or more scanning optical systems with respect to the rotating shaft of the deflection scanning means 20, the number of the reflecting mirrors 26, and the energizing directions of the fixing members are set in order to make the irradiation positions on the photoreceptors of the respective luminous fluxes vary in the same direction when the light source holding members are tilted against the energizing force of the fixing members. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a color laser beam printer or a color digital copying machine, and a scanning optical apparatus used therefor.

  2. Description of the Related Art Conventionally, a scanning optical device periodically deflects and scans a light beam that has been light-modulated from a light source according to an image signal, for example, by an optical deflector such as a rotating polygon mirror, and is exposed by an imaging optical system having fθ characteristics. Focus in a spot shape on the image plane on the body. An image forming apparatus having a scanning optical device forms an electrostatic latent image in accordance with main scanning by a deflector and sub-scanning by rotation of a photosensitive member, and performs image recording.

  In a tandem color laser printer, a number of light beams corresponding to a plurality of photosensitive members are irradiated onto the photosensitive member, and a color image is formed by superimposing the respective colors.

  As one of the causes of hindering image superposition, the light source holding member is inclined due to the heat expansion of the light source in the scanning optical device, the light source holding member is tilted, the irradiation position of the light beam on the photosensitive member is shifted, and color shift An example of a solution to this problem is described in Patent Document 1.

JP 2004-138647 A

  However, the technique described in Patent Document 1 has the following unsolved problems.

  In recent years, image forming apparatuses such as color leather beam printers and color digital copying machines have been required to be further reduced in cost and size. Accordingly, a scanning optical device has been proposed that uses only one expensive scanner motor and scans a plurality of independent light beams only on the same side or on both sides with respect to the rotation axis of the scanner motor.

  In such a scanning optical apparatus, in order to reduce the size of the entire apparatus, each light beam is folded by a plurality of folding means, and the number of folding means is not always the same for each light flux. Further, in such a scanning optical device, color misregistration due to fluctuations in the irradiation position of each light beam on the photosensitive member due to thermal deformation of the light source unit due to heat generation of the light source unit occurs.

  Therefore, the present invention can achieve downsizing and cost reduction, and can align the variation direction of the irradiation position of each light beam on the photosensitive member due to the thermal deformation of each light source holding member caused by the heat generation of each light source. It is an object of the present invention to provide a scanning optical device and an image forming apparatus that can reduce the deviation.

  In order to solve the above problems, a typical configuration of a scanning optical device according to the present invention includes a plurality of light sources, a light source holding member that holds the light sources, and deflection scanning means that deflects and scans a light beam emitted from the light sources. A plurality of scanning optical systems which are arranged on the same side or both sides with respect to the rotation axis of the deflection scanning means and scan the light beams deflected and scanned by the deflection scanning means on a separate photosensitive member for each light flux. And a housing member containing the light source holding member, the deflection scanning means, and the plurality of scanning optical systems, and urging the light source holding member with respect to the housing member in the direction of the rotation axis of the deflection scanning means. And a plurality of scanning optical systems each having a light beam folding means for folding the light beam, and at least a light beam folded by the plurality of light beam folding means is present. The light source holding member is attached to the light source holding member by setting the positions of the plurality of scanning optical systems with respect to the rotation axis of the deflection scanning means, the number of the light beam folding means, and the urging direction of the urging means. When tilted against the urging force of the urging means, the changing direction of the irradiation position of each light beam on the photosensitive member is set to the same direction.

  In order to solve the above problems, an image forming apparatus according to the present invention includes a scanning optical device, a plurality of photoconductors that are image-scanned by the scanning optical device, and formed on the plurality of photoconductors. Developing means for visualizing the electrostatic latent image formed into a toner image.

  According to the present invention, it is possible to reduce the size and cost, and to align the variation direction of the irradiation position of each light beam on the photoconductor due to the thermal deformation of each light source holding member generated by the heat generation of each light source. Color misregistration can be reduced.

[First embodiment]
A first embodiment of a scanning optical device and an image forming apparatus according to the present invention will be described with reference to the drawings.

(Color image forming device)
FIG. 13 is a configuration diagram of a color image forming apparatus provided with a scanning optical device. As shown in FIG. 13, the color image forming apparatus D of the present embodiment has a scanning optical device S1. Light beams LY to LK light-modulated based on the image information are emitted from the housing member 30 and irradiated onto the surfaces of the corresponding photoreceptors 40Y to 40K to form electrostatic latent images. The surfaces of the photoreceptors 40Y to 40K are uniformly charged by the primary chargers 43Y to 43K, respectively.

  The electrostatic latent images formed on the surfaces of the photoreceptors 40Y to 40K are visualized as cyan, magenta, yellow, and black toner images by developing units 44Y to 44K, which are developing units. On the other hand, the transfer material P placed on the feed tray is fed by the feed roller 45 and conveyed to the nip portion between the transfer belt 49 and the photoreceptor 40. The visualized cyan, magenta, yellow, and black toner images are sequentially transferred onto the transfer material P at each nip portion to form a color image.

  The drive roller 41 accurately feeds the transfer belt 49 and is connected to a drive motor (not shown) with little rotation unevenness. The color image formed on the transfer material P is thermally fixed by the fixing unit 47 and then discharged outside the apparatus by the discharge roller 48 or the like.

(Scanning optical device)
First, the scanning optical device S1 will be described. As shown in FIGS. 1 to 7, the scanning optical device S1 deflects and scans a plurality of light sources (semiconductor lasers 11Y to 11K), light source holding members 13Y to 13K that hold the light sources, and light beams emitted from the light sources. And deflection scanning means 20 for performing the above. The scanning optical device S1 is disposed only on the same side or on both sides with respect to the rotation shaft 20a of the deflection scanning unit 20, and the light beams LY to LK deflected and scanned by the deflection scanning unit 20 are separately sensitized for each light beam. It has a plurality of scanning optical systems for scanning on the bodies 40Y to 40K. The scanning optical device S1 includes a housing member 30 that includes light source holding members 13Y to 13K, the deflection scanning unit 20, and the plurality of scanning optical systems. The scanning optical device S1 has urging means (fixing members 15Y to 15K) for urging and fixing the light source holding members 13Y to 13K to the housing member 30 in the direction of the rotation shaft 20a of the deflection scanning means 20. Each of the plurality of scanning optical systems has a light beam folding means (folding mirrors 26Y1 to 26K2) for folding the light beam for each light beam, and at least a light beam that is folded by the plurality of light beam folding means exists. The positions of the plurality of scanning optical systems with respect to the rotation shaft 20a of the deflection scanning means 20, the number of the light beam folding means, and the urging direction of the urging means are set. Thereby, when the light source holding member 13 is tilted against the urging force of the urging means, the variation direction of the irradiation position of each light beam on the photosensitive member 40 is set to the same direction.

  FIG. 1A is a perspective view of the scanning optical device S1 according to this embodiment. FIG. 2 is a diagram showing the path of the light beam deflected by the deflection scanning means 20. FIG. 3 is a cross-sectional view showing the path of the light beam incident on the deflection scanning means 20.

  A scanning optical device S1 shown in FIG. 1A is a unit mounted on a tandem color image forming apparatus. The scanning optical device S1 performs optical scanning on the photoreceptors 40Y, 40M, 40C, and 40K corresponding to the colors yellow, magenta, cyan, and black. In the following description, for convenience, the scanning optical system corresponding to each color is referred to as a Y station, an M station, a C station, and a K station.

  The scanning optical device S1 includes light source units 10Y to 10K, a deflection scanning unit 20, and a housing member 30. As shown in FIG. 2, the scanning optical device S1 has a first scanning optical system on the left side and a second scanning optical system on the right side with respect to the rotation shaft 20a of the deflection scanning means 20.

  The light source units 10Y, 10M, 10C, 10K are semiconductor lasers (light sources) 11Y, 11M, 11C, 11K, collimator lenses 12Y, 12M, 12C, 12K, light source holding members 13Y, 13M, 13C, 13K, side surfaces 14Y, 14M, 14C, 14K.

  The semiconductor lasers 11Y to 11K are four light sources that are independently controlled to emit light according to image information. The collimator lenses 12Y to 12K correspond to the respective semiconductor lasers 11Y to 11K. The light source holding members 13Y to 13K hold the semiconductor lasers 11Y to 11K and the lenses 12Y to 12K with high accuracy.

  The deflection scanning unit 20 includes a rotary polygon mirror 21 that reflects the light beams emitted from the semiconductor lasers 11Y to 11K to the scanning lens side, and a motor unit 20b that rotates the rotary polygon mirror 21.

  The first scanning optical system and the second scanning optical system include first scanning lenses 23 and 24, second scanning lenses 25Y to 25K, folding mirrors 26Y1 to 26K1, 26M2, and 26C2 (light beam folding means), and a cylindrical lens 27. The first scanning optical system (Y station, M station) and the second scanning optical system (C station, K station) each scan two independent light beams.

  The housing member 30 is configured to accommodate the deflection scanning means 20, the scanning lenses 23, 24, 25Y to 25K, and the folding mirrors 26Y1 to 26K1, 26M2, and 26C2. The housing member 30 has V-shaped fixing portions 31Y, 31M, 31C, and 31K.

  In the Y station, the light beam LY emitted from the semiconductor laser 11Y is made into substantially parallel light by the lens 12Y, passes through the cylindrical lens 27, and is deflected by the deflection scanning means 20. The deflected light beam LY passes through the first scanning lens 23 and the second scanning lens 25Y, and is then guided to the photoconductor 40Y by a folding mirror 26Y1 of a plane mirror, thereby drawing a scanning line.

  In the M station, the light beam emitted from the semiconductor laser 11M is converted into substantially parallel light by the lens 12M, passes through the lens 27, and is deflected by the deflection scanning means 20. The deflected light beam LM passes through the first scanning lens 23, is changed in direction by the folding mirror 26M1, passes through the second scanning lens 25M, is guided to the photoconductor 40M by the folding mirror 26M2, and draws a scanning line. To do.

  The scanning optical device S1 has a substantially symmetrical shape except for the biasing direction of the light source unit on the Y station, M station side and C station, K station side. The C station has a configuration similar to the M station, and the K station has a configuration similar to the Y station.

  The number of folding mirrors in the Y station which is the first scanning optical system is one, and the number of folding mirrors in the M station is two. The number of folding mirrors in the C station, which is the second scanning optical system, is 2, and the number of folding mirrors in the K station is 1.

(Light source unit 10)
Next, the light source unit 10 corresponding to each station will be described. FIG. 4 is a configuration diagram of the light source unit mounting portion.

  As shown in FIG. 4, the light source units 10 </ b> Y to 10 </ b> K are fitted and fixed to V-shaped fixing portions 31 </ b> Y to 31 </ b> K provided in the housing member 30. The light source units 10Y to 10K are urged by fixing members 15Y, 15M, 15C, and 15K having an elastic function in a state where the cylindrical side surfaces 14Y to 14K are abutted against the fixing portions 31Y to 31K.

  The fixing portions 31Y to 31K are provided at two locations in the optical axis direction for one laser unit.

  The two light source units 10Y and 10M of the first scanning optical system are arranged in two stages in the rotation axis direction of the deflection scanning means 20. The direction of the fixed portion 31Y of one light source unit 10Y and the direction of the fixed portion 31M of the other light source unit 10M are opposite to each other with respect to the rotation axis direction of the deflection scanning unit 20. That is, the urging directions by the fixing members 15Y and 15M are opposite to each other.

  The two light source units 10C and 10K of the second scanning optical system are also arranged in the same manner as the first scanning optical system, except for the following points.

  The biasing direction of the light source unit 10Y where the number of folding mirrors of the first scanning optical system is an odd number and the biasing direction of the light source unit 10K where the number of folding mirrors of the second scanning optical system are an odd number are mutually The opposite direction. The biasing direction of the light source unit 10M in which the number of folding mirrors of the first scanning optical system is an even number and the biasing direction of the light source unit 10C in which the number of folding mirrors of the second scanning optical system is an even number are opposite to each other. is there.

  FIG. 5 is a diagram showing a state in which each light source unit 10 is fixed. FIG. 5 is a view showing a state before the light source unit 10 is tilted. FIG. 6 is a view showing a state in which the light source unit 10 is tilted.

  As shown in FIG. 5, due to the heat generated by the semiconductor laser 11, the light source holding member 13 that press-fits the semiconductor laser 11 is thermally expanded and deformed. Due to thermal expansion of the light source holding member 13 in the vicinity of the semiconductor laser 11, the light source holding member 13 is deformed from the state of FIG. 5 to the state of FIG. 6 against the urging force of the fixing member 15, and the light source unit 10 is tilted.

  Here, the variation of the irradiation position of the light beams LY to LK on the photoreceptors 40Y to 40K in the state where the light source units 10Y to 10K are inclined (state of FIG. 6) will be described.

  FIG. 7 is a diagram illustrating fluctuations in irradiation positions of the light beams LY to LK on the photoreceptors 40Y to 40K in the sub-scanning direction when the light source units 10Y to 10K are inclined. In FIG. 7, light beams LY to LK indicated by solid lines indicate the states of the light beams LY to LK that are not affected by the heat generated by the semiconductor laser 11 (the state in FIG. 5). Light beams LYa to LKa indicated by chain lines indicate the fluctuation state of the light beam (the state shown in FIG. 6) in the state affected by the heat generated by the semiconductor laser 11.

  Since the light source unit 10Y of the Y station is tilted in the direction of the arrow Y in FIG. 6, the light beam LY is transmitted through the scanning lenses 23 and 25Y and is folded back by one folding mirror 26Y1, and the position of the chain line LYa is 40Y on the photoreceptor. Fluctuates.

  Since the light source unit 10M of the M station is tilted in the direction of arrow M in FIG. 6, the light beam LM is transmitted through the scanning lenses 23 and 25M and is folded by the two folding mirrors 26M1 and 26M2, and the chain line LMa is 40M on the photoreceptor. It fluctuates to the position.

  Since the light source unit 10C of the C station is tilted in the direction of arrow C in FIG. 6, the light beam LC is transmitted through the scanning lenses 24 and 25C and folded by the two folding mirrors 26C1 and 26C2, and the chain line LCa on the photosensitive member 40C. It fluctuates to the position.

  Since the light source unit 10K of the K station is inclined in the direction of arrow K in FIG. 6, the light beam LK is transmitted through the scanning lenses 24 and 25K and is folded back by one folding mirror 26K1, and the position of the chain line LKa is 40K on the photoreceptor. The number of fluctuations.

  Therefore, since the irradiation position on the photosensitive member varies in the same direction at the four stations, it is possible to reduce color misregistration caused by thermal deformation of the light source holding members 13Y to 13K due to heat generated by the semiconductor lasers 11Y to 11K.

  As described above, in the present embodiment, the scanning direction with respect to the rotation axis direction of the deflection scanning unit 20, the number of the folding mirrors 26 on the light beam path emitted from each of the semiconductor lasers 11Y to 11K, and the light source holding members 13Y to 13K. It is defined in combination with the energizing direction. Thereby, the change direction of the irradiation position on the photoconductor generated by the thermal deformation of the light source holding members 13Y to 13K due to the heat generation of the semiconductor lasers 11Y to 11K can be made the same in the four stations. For this reason, it is possible to reduce the color misregistration even in the scanning optical device S1 in which the number of the folding mirrors 26 is different by sandwiching the deflection scanning unit 20 by using one deflection scanning unit 20 for miniaturization and cost reduction.

  In the present embodiment, the scanning optical system is constituted by a foldable mirror made up of a transmissive lens and a plane mirror, but the same effect can be obtained even if a curved mirror is used as the beam folding means.

  The same effect can be obtained by adjusting the urging directions of the light source units 10Y to 10K even in the oblique incidence optical system in which the light source unit 10 has an angle in advance and is incident on the deflection scanning unit 20. That is, as illustrated in FIG. 8, the variation direction of the irradiation position on the photosensitive member generated by the thermal deformation of the light source holding member 13 due to the heat generated by the semiconductor laser 11 is set to the same direction at the four stations. Thereby, the same effect as the scanning optical device S1 of the present embodiment can be obtained.

  In FIG. 8, the arrangement of the light source unit 10 is the same as that in FIG. 4 although the arrangement of 10Y and 10M, 10K and 10C in FIG.

[Second Embodiment]
Next, a second embodiment of the scanning optical device and the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 9 is an explanatory diagram of irradiation position fluctuation according to the present embodiment. FIG. 10 is a configuration diagram of a light source unit mounting portion according to the present embodiment. About the part which overlaps with said 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 9, the scanning optical apparatus according to the present embodiment adds the folding mirrors 26Y2 and 26K2 to the scanning optical apparatus S1 according to the first embodiment, so that the number of folding mirrors is an even number for all four stations. Is. In this embodiment, the number of the four folding stations is an even number. However, the folding mirrors 26M2 and 26C2 may be omitted from the scanning optical device S1 of the first embodiment, and the number of the folding mirrors may be an odd number for all four stations. .

  The energizing directions of the light source units 10Y to 10K when the number of folding mirrors is an even number for all four stations will be described with reference to FIG.

  The urging directions of the two light source units 10Y and 10M of the first scanning optical system are the same direction, and the urging directions of the two light source units 10C and 10K of the second scanning optical system are the same direction. Then, the urging directions of the light source units 10Y and 10M of the first scanning optical system and the urging directions of the light source units 10C and 10K of the second scanning optical system are opposite to each other.

  The variation direction of the irradiation position on the photosensitive member, which is generated by the heat deformation of the light source holding member 13 due to the heat generated by each of the semiconductor lasers 11Y to 11K, will be described with reference to FIG.

  In FIG. 9, light beams LY to LK indicated by solid lines indicate states of the light beams LY to LK that are not affected by the heat generated by the semiconductor laser 11. Light beams LYa to LKa indicated by chain lines indicate the fluctuation state of the light beam in the state affected by the heat generated by the semiconductor laser 11.

  Since the light beam LY of the Y station is tilted by the influence of thermal deformation of the light source holding member 13, it passes through the scanning lenses 23 and 25Y, is folded by the two folding mirrors 26Y1 and 26Y2, and is positioned on the photoconductor 40Y by the chain line LYa. Fluctuates.

  Since the M station beam LM is also tilted due to the thermal deformation of the light source holding member 13, it passes through the scanning lenses 23 and 25M, is folded by the two folding mirrors 26M1 and 26M2, and is positioned at the position of the chain line LMa by 40M on the photoreceptor. fluctuate.

  Since the light beam LC of the C station is also tilted due to the influence of thermal deformation of the light source holding member 13, it passes through the scanning lenses 24 and 25C, is folded by the two folding mirrors 26C1 and 26C2, and is positioned on the photoconductor 40C by the position of the chain line LCa. Fluctuates.

  Since the K station light beam LK is also tilted due to the influence of thermal deformation of the light source holding member 13, it passes through the scanning lenses 24 and 25M, is folded by the two folding mirrors 26M1 and 26M2, and is positioned at the position of the chain line LMa by 40M on the photoreceptor. fluctuate.

  Therefore, since the irradiation position on the photosensitive member varies in the same direction at the four stations, it is possible to reduce color misregistration caused by thermal deformation of the light source holding members 13Y to 13K due to heat generated by the semiconductor lasers 11Y to 11K.

  As described above, since the color shift can be reduced without being related to the even or odd number of the light beam folding means, the size of the entire apparatus can be reduced by increasing the number of the light beam folding means.

  In the present embodiment, the scanning optical system is constituted by a foldable mirror made up of a transmissive lens and a plane mirror, but the same effect can be obtained even if a curved mirror is used as the beam folding means.

  The same effect can be obtained by adjusting the urging directions of the light source units 10Y to 10K even in the oblique incidence optical system in which the light source unit 10 has an angle in advance and is incident on the deflection scanning unit 20. That is, as illustrated in FIG. 11, the variation direction of the irradiation position on the photosensitive member generated by the thermal deformation of the light source holding member 13 due to the heat generated by the semiconductor laser 11 is set to the same direction at the four stations. Thereby, the same effect as the scanning optical apparatus of this embodiment can be acquired.

  In FIG. 11, the arrangement of the light source unit 10 is the same as that in FIG. 10, although the arrangement of 10Y and 10M, 10K and 10C is replaced in FIG.

[Third embodiment]
Next, a third embodiment of the scanning optical device and the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 12 is an explanatory diagram of irradiation position fluctuation according to the present embodiment. About the part which overlaps with said 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 12, the scanning optical apparatus of the present embodiment scans all the light beams on one side with respect to the rotating shaft 20a of the deflection scanning means 20. In this scanning optical apparatus, on the same side with respect to the rotation axis 20a of the deflection scanning means 20, the folding mirror as the beam folding means is arranged in a mixture of an even number of Y to C stations and an odd number of K stations. .

  The urging directions of the light source units 10Y to 10C of the Y, M, and C stations where the number of folding mirrors is an even number and the light source units 10K of the K station that is an odd number are opposite to each other.

  The variation direction of the irradiation position on the photosensitive member generated by the thermal deformation of the light source holding member 13 due to the heat generated by each of the semiconductor lasers 11Y to 11K will be described with reference to FIG. In FIG. 12, light beams LY to LK indicated by solid lines indicate states of the light beams LY to LK that are not affected by the heat generated by the semiconductor laser 11. Light beams LYa to LKa indicated by chain lines indicate the fluctuation state of the light beam in the state affected by the heat generated by the semiconductor laser 11.

  The light beams LY, LC, and LM of the Y, C, and M stations change from a solid line state to a chain line state due to the influence of thermal deformation of the light source holding member 13, and are folded by an even number of folding mirrors 26Y1 to 26C2. The irradiation position varies in the middle arrow Z direction.

  The light beam K of the K station changes from a solid line state to a chain line state due to the influence of thermal deformation of the light source holding member 13, and is folded back by an odd number of folding mirrors 26K1, and the irradiation position varies in the direction of arrow Z in FIG. .

  Therefore, since the irradiation position on the photosensitive member varies in the same direction at the four stations, it is possible to reduce color misregistration caused by thermal deformation of the light source holding members 13Y to 13K due to heat generated by the semiconductor lasers 11Y to 11K.

  As described above, color misregistration can be reduced regardless of the number of light beam folding means. Further, by scanning all the light beams on one side with respect to the rotating shaft 20a of the deflection scanning means 20, the entire apparatus can be reduced in size and cost.

  In the present embodiment, the scanning optical system is constituted by a foldable mirror made up of a transmissive lens and a plane mirror, but the same effect can be obtained even if a curved mirror is used as the beam folding means.

  The same effect can also be obtained in an oblique incidence optical system in which the light source unit 10 is angled in advance and enters the deflection scanning means 20.

  In the present embodiment, a scanner motor having a rotary polygon mirror 21 in the deflection scanning unit 20 is assumed, but a galvanometer mirror may be used.

  The present invention is not limited to the first to third embodiments. For example, any scanning optical device having the following conditions may be used.

In the scanning optical system disposed on the same side with respect to the rotation shaft 20a of the deflection scanning means 20,
The light source holding member corresponding to the light beam that is oddly folded by the odd number of light beam folding means and the light source holding member corresponding to the light beam that is evenly folded by the even number of light beam folding means are biased in opposite directions,
The light source holding members corresponding to the light beams folded odd by the odd number of light beam folding means or the light source holding members corresponding to the light beams folded even by the even number of light beam folding means are urged in the same direction,
In the scanning optical system disposed on the opposite side to the rotation axis 20a of the deflection scanning means 20,
The light source holding member corresponding to the light beam that is oddly folded by the odd number of light beam folding means and the light source holding member corresponding to the light beam that is evenly folded by the even number of light beam folding means are urged in the same direction,
The light source holding members corresponding to the light beams that are oddly folded by the odd number of light beam folding means or the light source holding members corresponding to the light beams that are evenly folded by the even number of light beam folding means are biased in opposite directions. .

1 is a perspective view of a scanning optical device according to a first embodiment. It is a figure which shows the path | route of the light beam deflected by the deflection | deviation scanning means. 3 is a cross-sectional view showing a path of a light beam incident on a deflection scanning unit 20. FIG. It is a block diagram of a light source unit attachment part. It is explanatory drawing of a deformation | transformation of a light source unit. It is explanatory drawing of a deformation | transformation of a light source unit. It is explanatory drawing of irradiation position fluctuation | variation. It is explanatory drawing of a deformation | transformation of the light source unit of the other structure which concerns on 1st embodiment. It is explanatory drawing of the irradiation position fluctuation | variation which concerns on 2nd embodiment. It is a block diagram of the light source unit attachment part which concerns on 2nd embodiment. It is explanatory drawing of a deformation | transformation of the light source unit of the other structure which concerns on 2nd embodiment. It is explanatory drawing of the irradiation position fluctuation | variation which concerns on 3rd embodiment. 1 is a configuration diagram of an image forming apparatus according to a first embodiment.

Explanation of symbols

L ... Light beam S1 ... Scanning optical device 11 ... Semiconductor laser (light source)
13 ... Light source holding member 15 ... Fixing member (biasing means)
DESCRIPTION OF SYMBOLS 20 ... Deflection scanning means 20a ... Rotating shaft 26 ... Folding mirror (light beam folding means)
30 ... Housing member 40 ... Photoconductor

Claims (7)

Multiple light sources;
A light source holding member for holding the light source;
Deflection scanning means for deflecting and scanning a light beam emitted from the light source;
A plurality of scanning optical systems which are arranged on the same side or both sides with respect to the rotation axis of the deflection scanning means, and which scan light beams deflected and scanned by the deflection scanning means on a separate photoconductor for each light flux; ,
A housing member containing the light source holding member, the deflection scanning means, and the plurality of scanning optical systems;
Biasing means for biasing and fixing the light source holding member with respect to the housing member in the direction of the rotation axis of the deflection scanning means;
The plurality of scanning optical systems has a light beam folding means for folding a light beam for each light beam, and there is a light beam that is folded at least by the plurality of light beam folding means.
By setting the positions of the plurality of scanning optical systems with respect to the rotation axis of the deflection scanning means, the number of the light beam folding means, and the urging direction of the urging means, the light source holding member can be A scanning optical device characterized in that, when tilted against an urging force, the variation direction of the irradiation position of each light beam on the photosensitive member is the same. In the scanning optical system disposed on the same side with respect to the rotation axis of the deflection scanning means,
The light source holding member corresponding to the light beam that is oddly folded by the odd number of light beam folding means and the light source holding member corresponding to the light beam that is evenly folded by the even number of light beam folding means are biased in opposite directions,
The light source holding members corresponding to the light beams folded odd by the odd number of light beam folding means or the light source holding members corresponding to the light beams folded even by the even number of light beam folding means are urged in the same direction,
In the scanning optical system disposed on the opposite side to the rotation axis of the deflection scanning means,
The light source holding member corresponding to the light beam that is oddly folded by the odd number of light beam folding means and the light source holding member corresponding to the light beam that is evenly folded by the even number of light beam folding means are urged in the same direction,
The light source holding members corresponding to the light beams that are oddly folded by the odd number of light beam folding means or the light source holding members corresponding to the light beams that are evenly folded by the even number of light beam folding means are biased in opposite directions. The scanning optical apparatus according to claim 1. The plurality of scanning optical systems are first and second scanning optical systems disposed on opposite sides of the rotation axis of the deflection scanning unit,
Each of the first and second scanning optical systems has an odd number of light beam folding means and an even number of light beam folding means,
In each of the first and second scanning optical systems, a light source holding member corresponding to a light beam whose urging direction with respect to the housing member of the light source holding member is oddly folded by the odd number of light beam folding means, With the light source holding member corresponding to the light beam folded back evenly by the even number of light beam folding means, the directions are opposite to each other,
The biasing directions of the light source holding members corresponding to the light beams that are oddly folded back by the odd-numbered light beam folding means of the first scanning optical system and the second scanning optical system are opposite to each other,
The biasing directions of the light source holding members corresponding to the light beams that are folded back a plurality of times by the plurality of light beam folding means of the first scanning optical system and the second scanning optical system are opposite to each other. The scanning optical device according to claim 1. The plurality of scanning optical systems are first and second scanning optical systems disposed on opposite sides of the rotation axis of the deflection scanning unit,
The light beam folding means is provided with an odd number for every plurality of independent light fluxes, or is provided with an even number for every plurality of independent light fluxes,
2. The scanning optical apparatus according to claim 1, wherein an urging direction of the light source holding member with respect to the housing member is opposite in the first scanning optical system and the second scanning optical system. The plurality of scanning optical systems are a plurality of scanning optical systems disposed on the same side with respect to the rotation axis of the deflection scanning unit,
The plurality of scanning optical systems includes an odd number of light flux folding means for folding the light flux, and an even number of light flux folding means for folding the light flux,
The urging direction of the light source holding member with respect to the housing member corresponds to the light source holding member corresponding to the light beam that is oddly folded by the odd number of light beam folding means and the light beam that is evenly folded by the even number of light beam folding means. The scanning optical device according to claim 1, wherein the light source holding members are in opposite directions. The plurality of scanning optical systems are a plurality of scanning optical systems disposed on the same side with respect to the rotation axis of the deflection scanning unit,
The light beam folding means is provided with an odd number for every plurality of independent light fluxes, or is provided with an even number for every plurality of independent light fluxes,
The scanning optical apparatus according to claim 1, wherein the urging directions of the light source holding members with respect to the housing member are all the same direction. A scanning optical device according to any one of claims 1 to 6,
A plurality of photosensitive members that are image-scanned by the scanning optical device;
An image forming apparatus comprising: a developing unit that visualizes the electrostatic latent images formed on the plurality of photoconductors into toner images.

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