JP2009198873A - Optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner and an image forming apparatus in which a distance between image carriers can be easily shortened and the apparatus can be made compact. <P>SOLUTION: First and second optical scanning units 31, 41 emitting light beams to a plurality of photoreceptors 7 disposed in an array in a laser printer 1 are superposed in this order in an approximately perpendicular direction with respect to a plane along which the photoreceptors 7 are arranged, and the scanning units are arranged to give such a positional relation that directions of beams from the respective polygon mirrors 36, 46 are opposed to each other. Reflection mirrors 48a to 48d of the second optical scanning unit 41 are disposed in such a manner that beams L3, L4 reflected by the reflection mirrors 48a to 48d intersect either between the polygon mirror 36 and a scanning lens 37 in the first scanning unit 31 or between the scanning lens 37 and the reflection mirror 38b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical scanning apparatus that forms a latent image on an image carrier and an image forming apparatus such as a printer, a facsimile, a copying machine, or a complex machine using these.

  In general, this type of optical scanning apparatus deflects a light beam from a light source by an optical deflector, condenses it toward a surface to be scanned by a scanning imaging optical system such as an fθ lens, and focuses an optical spot on the surface to be scanned. And the surface to be scanned is optically scanned (main scanning) with this light spot. What constitutes the surface to be scanned is a photosensitive surface such as a photoconductor which is a photoconductive photosensitive medium. For example, four photoconductors are arranged in the conveyance direction of the recording paper, and each of these photoconductors is arranged. A light beam emitted from a plurality of corresponding light sources is deflected and scanned by a set of deflecting means, and each photosensitive member is exposed simultaneously by a plurality of scanning imaging optical systems corresponding to each photosensitive member. Latent images are created, and these latent images are visualized with a developing device using different color developers such as yellow, magenta, cyan, and black, and then these visible images are sequentially superimposed on the same recording paper. The color image can be obtained by transferring and fixing.

  As described above, an image forming apparatus that uses a plurality of combinations of optical scanning devices and photoconductors to obtain a two-color image, a multicolor image, a color image, or the like is a “tandem type image forming apparatus” or “ It is known as a “tandem type image forming apparatus” (for example, see Patent Document 1).

  As an optical scanning device used for such a tandem type image forming apparatus, a single optical deflector is used to irradiate a plurality of photosensitive members with light beams from both sides with respect to a single optical deflector. A light beam is incident so as to face each other, and each is guided to a scanning surface by a corresponding scanning imaging optical system (see, for example, Patent Document 2) or from a single direction of a single deflector. Compared to a configuration in which a plurality of light beams are incident on the same deflecting reflection surface and guided to the surface to be scanned by the scanning imaging optical system, and an optical deflector is provided corresponding to each photoconductor. A technology for reducing the size of the device is known. As this one-side scanning method, there is known a configuration in which an optical housing that irradiates a plurality of photoconductors with a light beam by a single optical deflector is arranged along the alignment direction of the photoconductors (for example, Patent Document 3 and 4).

Japanese Patent No. 2725067 JP 2006-267398 A JP 2005-153347 A JP 2005-208176 A

  In the above-described prior art, the light is guided to the four photoconductors by the one-side scanning method or the counter scanning method. However, in order to reduce the size of the entire image forming apparatus, each component is reduced. It is necessary to reduce the distance between the photoconductors, and as the distance between the photoconductors becomes narrower, the arrangement of the reflection means for forming the optical path becomes stricter. As a result, there is a problem in that it is difficult to reduce the distance between the photoconductors and it is difficult to reduce the size of the apparatus.

  It is an object of the present invention to obtain an optical scanning device and an image forming apparatus that can easily reduce the distance between image carriers and can reduce the size of the apparatus.

  In order to solve the above-mentioned problem, the invention described in claim 1 includes: first and second optical scanning units that emit light beams toward a plurality of image carriers arranged in a line in the image forming apparatus. Each of these optical scanning units includes a light deflecting means for deflecting and scanning a light beam from a light source, a focusing means for focusing the light beam deflected by the light deflecting means, and a light beam from the focusing means. Reflecting means for reflecting toward the image carrier are arranged in this order and in a line along the direction in which the image carriers are arranged, and a light beam is irradiated onto each image carrier from each light scanning unit. Thus, the optical scanning device forms a latent image on the image carrier, and the first and second optical scanning units overlap in this order in a substantially vertical direction with respect to a plane along the arrangement direction of the image carriers. The directions of the light beams from the respective light deflecting means are mutually The reflecting means of the second optical scanning unit is arranged so as to face each other. The light beam reflected by the reflecting unit is between the light deflecting unit and the focusing unit of the first optical scanning unit and the first optical scanning unit. It is characterized by being arranged so as to cross either between the focusing means and the reflecting means.

  According to a second aspect of the present invention, in the first aspect of the invention, the first and second optical scanning units are respectively housed, and these housings are arranged in the arrangement direction of the image carriers. It is assembled so that it may overlap in the substantially perpendicular direction with respect to the surface along.

  The invention described in claim 3 is characterized in that, in the invention described in claim 1, a single housing for housing the first and second optical scanning units is provided.

  The invention described in claim 4 is the invention described in claim 2 or 3, wherein the housing is provided with a mounting portion for the image forming apparatus.

  According to a fifth aspect of the present invention, in the image forming apparatus including a plurality of image carriers arranged in a line, the optical scanning device according to any one of the first to fourth aspects is provided. An image forming apparatus characterized by the above.

  According to the present invention, the first and second optical scanning units are provided so as to overlap in this order in a direction substantially perpendicular to the arrangement direction of the image carriers. Compared to the arrangement arranged along the arrangement direction of the carriers, the distance between the image carriers can be easily reduced, and the apparatus can be downsized.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view schematically showing a tandem-type full-color laser printer according to an embodiment of the present invention, and FIG. 2 is a longitudinal section schematically showing a configuration of an optical scanning device provided in the copying machine of FIG. FIG. 3 is a plan view schematically showing the configuration of the first and second optical scanning units of the optical scanning device of FIG.

  A laser printer (image forming apparatus) 1 shown in FIG. 1 generally includes a paper feeding device 3, a conveyor belt 5, photoconductors 7K, 7C, 7M, and 7Y, charging chargers 11K, 11C, 11M, and 11Y, an optical scanning device 13, and development. Devices 15K, 15C, 15M, 15Y, transfer chargers 17K, 17C, 17M, 17Y, cleaning devices 9K, 9C, 9M, 9Y, registration rollers 19, belt charging charger 21, fixing device 23, paper discharge tray 27, and paper discharge rollers 25.

  In FIG. 1, a transfer sheet (not shown) fed from a sheet feeding device 3 disposed horizontally in the lower side of the apparatus is conveyed toward a fixing device 23 by a conveying belt 5 through a registration roller 19. It has become. On the conveyor belt 5, a yellow Y photoconductor 7Y, a magenta M photoconductor 7M, a cyan C photoconductor 7C, and a black K photoconductor 7K are sequentially arranged from the upstream side at equal intervals. ing. In the present embodiment, the photoconductors 7K, 7C, 7M, and 7Y are arranged in this order, but the order of arrangement is not limited to this, and it goes without saying that the arrangement can be changed as appropriate.

  In the following description, for the same configuration relating to each color of yellow Y, magenta M, cyan C, and black K, subscripts Y, M, C, and K are added to the common reference numerals, and each color is indicated by the subscript. A distinction shall be made. The photoreceptors 7K, 7C, 7M, and 7Y are simply referred to as the photoreceptor 7 when collectively referred to.

  These photoconductors 7Y, 7M, 7C, and 7K are all formed as drums having the same diameter, and the photoconductors 7Y, 7M, 7C, and 7K are parallel to each other and in a line on the conveyance belt 5. They are arranged in a line (in the left-right direction in FIG. 1). Around these photoreceptors, process members according to a normal electrophotographic process are sequentially arranged. For example, for the photoconductor 7Y, a charging charger 11Y, a developing device 15Y, a transfer charger 17Y, a cleaning device 9Y, and the like are sequentially arranged. Similarly, for the photoconductor 7M, a charging charger 11M, a developing device 15M, a transfer charger 17M, a cleaning device 9Y, and the like are sequentially arranged. For the photoconductor 7C, a charging charger 11C, a developing device 15C, and a transfer charger 17C. And a cleaning device 9C and the like are sequentially arranged. For the photosensitive member 7K, a charging charger 11K, a developing device 15K, a transfer charger 17K, a cleaning device 9K and the like are sequentially arranged. Each photoconductor 7 is subjected to writing scanning by the optical scanning device 13 between the charging charger 11 and the developing device 15.

  That is, the photosensitive surfaces of the photoconductors 7Y, 7M, 7C, and 7K are scanned surfaces set for each color, and the light scanning device 13 uses a light beam in a one-to-one correspondence for each color from the optical scanning device 13. Writing is performed. Further, a registration roller 19 and a belt charging charger 21 are provided around the transport belt 5 on the upstream side of the photoconductor 7K, and a belt separation charger (not shown) is provided on the downstream side of the photoconductor 7Y. A neutralizing charger and a cleaning device for the conveyor belt 5 are sequentially provided. Further, a fixing device 23 is provided downstream of these members in the transport direction, and the transfer paper that has passed through the fixing device 23 passes through a paper discharge roller 25 and reaches a paper discharge tray 27.

  In such a configuration, for example, in a multi-color mode in which a plurality of colors are printed, that is, in a full color mode, yellow Y, magenta M, cyan C, An electrostatic latent image of each color is formed by optical scanning of the light beam of each color by the optical scanning device 13 based on the image signal for each color of black K. These electrostatic latent images are developed with the corresponding color toners to become toner images, and are sequentially transferred onto transfer paper that is electrostatically attracted and conveyed on the conveying belt 5 of the conveying device. After being combined and fixed as a full-color image, the sheet is discharged onto a discharge tray 27 via a discharge roller 25.

  As shown in FIGS. 2 and 3, the optical scanning device 13 is disposed above the photosensitive member 7, and includes a first optical scanning unit 31 that emits a light beam to the photosensitive members 7K and 7C, and the photosensitive members 7M and 7Y. A second light scanning unit 41 for emitting a light beam.

  The first optical scanning unit 31 includes a semiconductor laser (light source) 32 that emits a laser beam that is a light beam, a collimating lens 33, an aperture 34, a cylindrical lens 35, a rotating unit having a reflecting surface formed around it, A polygon mirror (light deflecting means) 36 having a rotating shaft that rotatably supports the rotating portion, a scanning lens (focusing means) 37 that focuses the light beam deflected by the polygon mirror 36, and the scanning lens 37 Reflection mirrors (reflecting means) 38a, 38b, 38c, 38d for reflecting the laser beam from the laser beam, and a first housing part 39 for storing them. In the present embodiment, the rotating portion of the polygon mirror 36 is driven to rotate clockwise in FIG. 3, but this rotation direction is not particularly limited and can be changed as appropriate according to the specifications of the apparatus. Needless to say.

  The first casing 39 is open at the top and has a rectangular parallelepiped box shape that is long in the depth direction (the direction penetrating the paper surface in FIG. 2, the vertical direction in FIG. 3). Openings 39a, 39b, 39c, and 39d for allowing the light beams from the first and second light scanning sections 31 and 41 to pass therethrough are formed. Each of these openings 39a, 39b, 39c, and 39d has an elongated rectangular parallelepiped shape that extends in the axial direction of the photosensitive member 7, and is formed at a predetermined interval from each other. Each of these openings 39a, 39b, 39c, and 39d is provided with a single or a plurality of dust-proof members (not shown) such as flat glass and lenses in order to prevent intrusion of dust from the surroundings. Yes.

  As shown in FIG. 3A, a semiconductor laser 32 is provided on the back side and the left side portion in the first housing portion 39, and at the center and the left side in the first housing portion 39. A polygon mirror 36 is provided in the portion. Between the semiconductor laser 32 and the polygon mirror 36, a collimating lens 33, an aperture 34, and a cylindrical lens 35 are arranged in this order and in a straight line that is substantially parallel to the opening 39a. FIG. 3A is a plan view of the first optical scanning unit 31. In FIG. 3A, reflection mirrors 38b, 38a, 38d, and 38c described later are omitted.

  As shown in FIG. 2, a polygon mirror 36, a scanning lens 37, and reflection mirrors 38b, 38a, 38d, and 38c are arranged in the first casing 39 along the alignment direction of the photosensitive members 7 in a plan view (FIG. 2). Are arranged in a row and spaced from each other. In other words, the polygon mirror 36, the scanning lens 37, and the reflection mirrors 38b, 38a, 38d, and 38c are moved in the traveling direction of the laser beams L1 and L2 from the polygon mirror 36 in the plan view (the direction toward the right in FIG. 2). Are arranged in this order along.

  In the present embodiment, each member in the first housing part 39 is directly supported by a support member provided in the first housing part 39. In the case where the first housing part 39 is formed of a resin molded product, such a support member can be formed relatively easily. In addition, when integral molding in the first housing part 39 is difficult, the support part-like first housing part 39 may be attached as a separate part.

  Of the reflecting mirrors 38a to 38d in the first casing 39, the reflecting mirror 38c is positioned slightly higher than the polygon mirror 36 on the right side in the first casing 39, and will be described later. It is arranged below the 41 polygon mirror 46, and reflects a laser beam L2, which will be described later, diagonally downward to the left in FIG. Further, the reflection mirror 38d is disposed at a position lower than the polygon mirror 36 in FIG. 2 and obliquely above and to the left of the opening 39d. The reflection mirror 38d reflects the laser light L2 from the reflection mirror 38c obliquely to the right and opens the opening 39d. Irradiation is directed toward the photoconductor 7Y.

  Similarly, among the reflecting mirrors 38a to 38d in the first housing portion 39, the reflecting mirror 38a is disposed at a position lower than the polygon mirror 36 in FIG. 2 and between the opening 39c and the reflecting mirror 38d. The laser beam L1, which will be described later, is reflected obliquely upward to the left. The reflection mirror 38b is disposed at a position higher than the polygon mirror 36 and obliquely below and to the left of a scanning mirror 47 of the second light scanning unit 41 described later. And is irradiated toward the photoconductor 7M through the opening 39c.

  With such a configuration, the laser beam (light beam) is emitted by the first scanning unit 31 as follows. That is, the laser light emitted from the semiconductor laser 32 passes through the collimator lens 33, is shaped by the aperture 34, and enters the cylindrical lens 35, which is a line imaging optical system. The cylindrical lens 35 has power in the sub-scanning direction and is focused at an angle in the sub-scanning direction near the reflecting surface of the rotating portion of the polygon mirror 36 (so-called oblique incidence optical system). . For this reason, the laser beams reflected by the reflecting surface are divided into two upper and lower laser beams L1 and L2 that spread at an angle in the sub-scanning direction (in this embodiment, the lower laser beam is L1 and the upper laser beam These laser beams are deflected equiangularly with the rotation of the rotating portion of the polygon mirror 36 and directed toward the scanning lens 37. The two laser beams L1 and L2 transmitted through the scanning lens 37 are respectively guided to the photoreceptors 7M and 7Y by the reflection mirrors 38a to 38d as described above.

  The second optical scanning unit 41 includes a semiconductor laser 42 that emits a laser beam, which is a light beam, a collimating lens 43, an aperture 44, a cylindrical lens 45, a rotating unit having a reflecting surface around it, and the rotating unit. A polygon mirror (light deflecting means) 46 having a rotating shaft that is rotatably supported, a scanning lens (focusing means) 47, and reflecting mirrors (reflecting means) 48a and 48b for reflecting the laser light from the scanning lens 47. , 48c, 48d, and a second housing portion 49 for storing them. In the present embodiment, the rotating portion of the polygon mirror 46 is driven to rotate clockwise in FIG. 3, but this rotating direction is not particularly limited and can be changed as appropriate according to the specifications of the apparatus. Needless to say.

  The second casing portion 49 is open at the bottom and has a rectangular parallelepiped box shape that is long in the depth direction (the direction penetrating the paper surface in FIG. 2, the vertical direction in FIG. 3). It has the same shape as the body part 39.

  As shown in FIG. 3B, a semiconductor laser 42 is provided on the back side and the right side in the first housing part 49, and in the center and on the right side in the second housing part 49. A polygon mirror 46 is provided in the portion. Between these semiconductor lasers 42 and the polygon mirror 46, a collimating lens 43, an aperture 44, and a cylindrical lens 45 are arranged in this order, and the semiconductor laser 32, the collimating lens 33, the aperture 34, The cylindrical lens 35 and the polygon mirror 36 are arranged in a straight line that is substantially parallel to the direction in which the cylindrical lens 35 and the polygon mirror 36 are arranged. FIG. 3B is a plan view of the second optical scanning unit 31. In FIG. 3B, illustration of reflecting mirrors 38b, 38a, 38d, and 38c, which will be described later, is omitted, and each configuration is shown. The elements are shown in solid lines for easy viewing.

  As shown in FIG. 2, a polygon mirror 46, a scanning lens 47, and reflection mirrors 48d, 48b, 48c, and 48a are arranged in the second casing 49 along the alignment direction of the photosensitive members 7 in a plan view (FIG. 2). Are arranged in a row and spaced from each other. In other words, the polygon mirror 46, the scanning lens 47, and the reflection mirrors 48d, 48b, 48c, and 48a are arranged in this order along the traveling direction of the laser light from the polygon mirror 46 in the plan view (the direction toward the left in FIG. 2). The polygon mirror 46 of the second optical scanning unit 41 and the polygon mirror 36 of the first optical scanning unit 31 are arranged side by side, and laser beams L1 and L2 from the polygon mirror 36 and laser beam L3 from the polygon mirror 46 are arranged. , L4 are arranged so as to be in a positional relationship facing each other.

  In the present embodiment, each member in the second housing part 49 is also directly supported by a support member provided in the second housing part 49. In the case where the second housing portion 49 is formed of a resin molded product, such a support member can be formed relatively easily. In addition, when integral molding in the second housing part 49 is difficult, the support member may be attached in the second housing part 49 as a separate part.

  Among the reflecting mirrors 48 a to 48 d in the second housing part 49, the reflecting mirror 48 a is slightly lower than the polygon mirror 36 on the left side in the second housing part 49 and of the first light scanning part 31. A laser beam L3, which will be described later, is reflected obliquely downward to the left in FIG. 2, and this laser beam L3 is applied to the photoreceptor 7K through the opening 39a of the first casing 39. It comes to irradiate towards. That is, the reflection mirror 48a is disposed at a position where the laser light L3 exits from the opening 39a across the polygon mirror 36 and the scanning lens 37 of the first light scanning unit 31.

  Similarly, among the reflecting mirrors 48a to 48d in the second casing 49, the reflecting mirror 48b is located at a position higher than the polygon mirror 36 in FIG. 2, and the scanning lens 37 of the first optical scanning unit 31 It is arranged above and in the vicinity of the top plate 49 of the second housing part 49, and reflects a laser beam L4, which will be described later, obliquely downward to the left. Further, the reflection mirror 48c is disposed at a position lower than the reflection mirror 48a in FIG. 2 and between the polygon mirror 36 and the scanning mirror 37 of the first light scanning unit 31, and the laser beam from the reflection mirror 48b. L4 is reflected diagonally downward to the right.

  The reflection mirror 48d is located at substantially the same height as the reflection mirror 48c in FIG. 2 and is disposed obliquely to the upper right of the scanning lens 37 of the first light scanning unit 31, and the laser beam L4 from the reflection mirror 48c. Is reflected obliquely downward to the right, and irradiated to the photoreceptor 7C through the opening 39b. That is, the reflection mirror 48d is disposed at a position where the laser light L4 exits from the opening 39b across the scanning lens 37 of the first light scanning unit 31 and the reflection mirror 38b. Since the scanning lens 37 of the first light scanning unit 31 is sandwiched between the laser beams L3 and L4, the size of the scanning lens 37 in the optical axis direction (left-right direction in FIG. 2) It is desirable that the distance is smaller than the distance between the laser beams L3 and L4.

  With such a configuration, the laser beam (light beam) is emitted by the second scanning unit 41 as follows. That is, the laser light emitted from the semiconductor laser 42 passes through the collimating lens 43, is beam-shaped by the aperture 44, and enters the cylindrical lens 45 that is a line imaging optical system. The cylindrical lens 45 has power in the sub-scanning direction and is condensed with an angle in the sub-scanning direction near the reflection surface of the rotating portion of the polygon mirror 46 (so-called oblique incidence optical system). Therefore, the upper and lower laser beams L3 and L4 that spread at an angle in the sub-scanning direction are reflected on the reflecting surface (in this embodiment, the lower laser beam is L3 and the upper laser beam is L3). The laser beams L3 and L4 are deflected equiangularly with the rotation of the rotating portion of the polygon mirror 46 and directed toward the scanning lens 47. The two laser beams L3 and L4 that have passed through the scanning lens 47 are respectively guided to the photoreceptors 7K and 7C by the reflection mirrors 48a to 48d as described above.

  In FIG. 3, reference numerals M1 and M2 are synchronous mirrors of the first and second optical scanning units 31 and 41, respectively, and reference numerals D1 and D2 are semiconductors of the first and second optical scanning units 31 and 41, respectively. This is a synchronization detection device that is arranged in the vicinity of the lasers 32 and 42, receives the laser light reflected by the synchronization mirrors M1 and M2, obtains a horizontal synchronization signal, and synchronizes each scan.

  In the present embodiment, as described above, the first housing part 39 of the first optical scanning unit 31 is formed in a box shape having an opening on the lower side, and the second housing part 49 of the second optical scanning unit 41 is on the upper side. It is formed in an open box shape, and by closing the opening sides of the casing portions 39 and 49 together, a single rectangular parallelepiped sealed casing 50 is configured. That is, the first and second optical scanning units 31 and 41 are arranged above the photoconductor 7 so as to overlap each other in the order of the first housing unit 31 and the second housing unit 41 from the bottom. As described above, since the space between the first and second casing portions 39 and 49 is a space where no partition plate or the like is formed, this space can be used effectively.

  Accordingly, the distance between the photoconductors 7 can be easily reduced as compared with the configuration in which the first and second optical scanning units 31 and 41 are arranged along the alignment direction of the photoconductors 7, and the conveyance is accompanied accordingly. The size of other components such as the belt 5 can also be reduced. As a result, the apparatus can be reduced in size. In the present embodiment, the distance between the photoconductors 7 is set to about 25 mm.

  A boundary line between the first optical scanning unit 31 and the second optical scanning unit 41 in the housing 50 is as shown by a one-dot chain line in FIG. 2, and the first optical scanning unit 31 and the second optical scanning unit 41 are connected to each other. The optical scanning units 31 and 41 are arranged so as not to interfere with each other. For this reason, when assembling the housing 50, the opening of the first housing portion 39 and the second housing portion 49 can be simply joined (fitted) as they are, and the assembly is easy.

  In addition, since the first and second light scanning units 31 and 41 can be separated independently by the first and second housing units 39 and 49, the first and second light scanning units 31 and 41 are separated from each other. When assembling, it is easy to check whether or not desired optical characteristics are obtained at the position where the photoconductor 7 is finally exposed by attaching various optical elements to each of the casing portions 39 and 49. be able to. In addition, by forming an uneven portion or the like that fits to each other at a joint portion between the first housing portion 39 and the second housing portion 49, the housing 50 can be simply fitted. The formation is desirable from the viewpoint of ease of attachment.

  In the present embodiment, a mounting portion (not shown) for the laser printer 1 is formed on the bottom surface portion of the housing 50, in other words, the bottom surface portion of the first housing portion 39. By attaching the housing 50 to the laser printer 1, the optical scanning device 13 can be attached to the laser printer 1. In addition, as a mounting part, an appropriate thing can be applied, such as using a convex part or a concave part that fits into a concave part or a convex part formed in the laser printer 1, and the formation part is a part of the housing 50. Good anywhere. In short, there is no particular limitation as long as the optical scanning device 13 can be attached to the laser printer 1. By providing such an attaching portion, the optical scanning device 13 can be supported and fixed to the laser printer 1 and the assembling work can be easily performed.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. In the modified examples described below, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified.

  In the embodiment described above, the arrangement of the members in the housing 50 is as shown in FIGS. 2 and 3, but any one of the laser beams L1 to L4 of the first optical scanning units 31 and 41 is used. Are arranged such that each member passes between the polygon mirror 36 and the scanning lens 37 of the first optical scanning unit 31 and between the scanning lens 37 and the reflection mirrors 38a to 38d. There is no particular limitation on the arrangement of the optical scanning units 31 and 41 as long as they can be superimposed on each other. Examples of these arrangements are shown in FIGS. 4 to 8 below.

  In the modification shown in FIG. 4, (1) the reflection mirror 48 a of the second light scanning unit 41 so that the laser beams L 3 and L 4 pass between the polygon mirror 36 and the scanning lens 37 of the first light scanning unit 31. (2) The scanning lenses 37 and 47 are arranged so as to be vertically arranged between the opening 39b and the opening 39c. These (1) and (2) are shown in the figure. This is different from the arrangement shown in FIG.

  In the modification shown in FIG. 5, (1) the reflection mirror 38b of the first light scanning unit 31 is disposed in the vicinity of the top plate 39f of the second housing unit 39 in the second light scanning unit 41, and the laser light L1 is emitted. (2) The reflection mirror 48a of the second light scanning unit 41 is positioned higher than the polygon mirror 36, and the laser beam L4 is passed between the scanning lens 47 and the reflection mirror 48b of the second light scanning unit 41. (3) The point that the reflection mirror 48c of the second light scanning unit 41 reflects the laser beam L3 obliquely upward to the right, and (4) the second light scanning. The reflection mirror 48b of the part 41 reflects the laser beam L3 from the reflection mirror 48c directly toward the photoconductor 7C, and the reflection mirror 48d shown in FIG. 2 is not provided. (1) to (4) ) In the arrangement shown in FIG. You have me.

  In the modification shown in FIG. 6, (1) the reflection mirror 48b of the second optical scanning unit 41 passes the laser beam L3 between the polygon mirror 36 of the first optical scanning unit 31 and the scanning lens 37. (2) The reflection mirror 38b of the first light scanning unit 31 is disposed so as to pass the laser light L1 between the polygon mirror of the second light scanning unit 41 and the scanning lens 47. (3) The scanning lenses 37 and 47 are arranged so as to be vertically arranged between the opening 39b and the opening 39c. In these points (1) to (3), the arrangement shown in FIG. Is different.

  In the modification shown in FIG. 7, (1) the reflection mirror 48b of the second light scanning unit 41 is disposed so as to reflect the laser light L4 obliquely upward to the right, and (2) the second light scanning. The reflection mirror 48c of the portion 41 is arranged on the right side of the reflection mirror 48b and at a position higher than the reflection mirror 48b so as to reflect the laser beam L4 from the reflection mirror 48c directly toward the photoconductor 7C. (3) The reflection mirror 38a of the first light scanning unit 31 is positioned higher than the polygon mirror 36 and is arranged so as to reflect the laser beam L2 obliquely upward to the left. (4) The reflection mirror 38b of the first light scanning unit 31 is positioned in the vicinity of the top plate 49f of the second housing unit 49, and the laser beam L2 from the reflection mirror 38a is reflected toward the photoconductor 7M. Arranged to do (5) The point that the reflection mirror 38d of the first light scanning unit 31 is located on the right side of the opening 39d and is arranged so as to reflect the laser light L1 obliquely upward to the left, and (6) the first light. The reflection mirror 38c of the scanning unit 31 is disposed above the reflection mirror 38d and below the scanning lens 47 of the second light scanning unit 41 so as to reflect the laser light L3 from the reflection mirror 38d toward the photoreceptor 7Y. In these points (1) to (6), the arrangement differs from that shown in FIG.

  In the modification shown in FIG. 8, (1) the reflection lenses 48b and 48c of the second light scanning unit 41 are arranged so that the laser light L3 passes between the polygon lens 36 and the scanning lens 37 of the first light scanning unit 31. FIG. 7 shows that the scanning lenses 37 and 37 are arranged so as to be vertically arranged between the opening 39b and the opening 39c, and the points (1) and (2). Different from the arrangement shown in.

  In the modified examples shown in FIGS. 5 to 8, the reflection lens 38 b of the first optical scanning unit 31 is disposed so as to enter the region of the second optical scanning unit 41. The height of the housing 50 shown can be made lower than that of the housing 50 shown in FIG. 2, and further miniaturization can be achieved.

  Further, in the above-described embodiment, the first and second optical scanning units 31 and 41 are arranged so as to overlap above the photosensitive member 7, but the present invention is not limited to this, and the first and second optical scanning units 31 are arranged. , 41 may be arranged so as to overlap in a substantially vertical direction with respect to the surface along the alignment direction of the photoconductors 7. Specifically, according to the specifications of the laser printer 1, the first and second light scanning units 31 and 41 may be disposed below the photoconductor 7 so as to overlap each other. Even in this case, the same effect is obtained. In this case, it goes without saying that an attachment portion for the laser printer 1 may be provided in the upper portion of the housing 50.

  Furthermore, in the above-described embodiment, the first and second light scanning units 31 and 41 are housed in the single housing 50, but instead of this, a housing for housing the first light scanning unit 31 and Also, separate housings for storing the second optical scanning unit 41 may be provided, and these may be assembled vertically.

1 is a cross-sectional view schematically showing a tandem type full color laser printer according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view schematically showing a configuration of an optical scanning device provided in the copying machine of FIG. 1. FIG. 3 is a plan view schematically showing a configuration of first and second optical scanning units of the optical scanning device in FIG. 2. It is a longitudinal cross-sectional view which shows schematically the structure of the optical scanning device which concerns on a modification. It is a longitudinal cross-sectional view which shows schematically the structure of the optical scanning device which concerns on a modification. It is a longitudinal cross-sectional view which shows schematically the structure of the optical scanning device which concerns on a modification. It is a longitudinal cross-sectional view which shows schematically the structure of the optical scanning device which concerns on a modification. It is a longitudinal cross-sectional view which shows schematically the structure of the optical scanning device which concerns on a modification.

Explanation of symbols

1 Laser printer (image forming device)
7K, 7C, 7M, 7Y photoconductor (image carrier)
DESCRIPTION OF SYMBOLS 11 Operation part 13 Optical scanning device 31 1st optical scanning part 32, 42 Semiconductor laser (light source)
36, 46 Polygon mirror (light changing means)
37, 47 Scanning lens (focusing means)
38a to 38d, 48a to 48d Reflection mirror (reflection means)
41 2nd optical scanning part 50 Case

Claims (5)

The image forming apparatus includes first and second light scanning units that emit light beams toward a plurality of image carriers arranged in a line in the image forming apparatus, and each of the light scanning units deflects a light beam from a light source. The light deflecting means for scanning, the converging means for converging the light beam deflected by the light deflecting means, and the reflecting means for reflecting the light beam from the converging means toward the image carrier are arranged in this order and the image. The optical scanning device is arranged in a line along the alignment direction of the carrier, and forms a latent image on the image carrier by irradiating a light beam onto each image carrier from each optical scanning unit. And
The first and second light scanning units overlap in this order in a substantially vertical direction with respect to the surface along the arrangement direction of the image carriers, and the light beams from the respective light deflecting units are positioned so as to face each other. Placed in
The reflecting means of the second optical scanning unit is configured such that the light beam reflected by the reflecting means is between the light deflecting unit and the focusing unit of the first optical scanning unit and between the focusing unit and the reflecting unit of the first optical scanning unit. An optical scanning device characterized by being arranged so as to cross either of them.   It is characterized by comprising a housing for storing each of the first and second optical scanning units, and these housings are assembled so as to overlap in a substantially vertical direction with respect to a surface along the arrangement direction of the image carriers. The optical scanning device according to claim 1.   The optical scanning device according to claim 1, further comprising a single casing that houses the first and second optical scanning units.   4. The optical scanning device according to claim 2, wherein a mounting portion for the image forming apparatus is provided in the housing. In an image forming apparatus including a plurality of image carriers arranged in a row,
An image forming apparatus comprising the optical scanning device according to claim 1.

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