JP5857557B2 - Image forming apparatus and color image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus provided with an optical scanning device of a laser writing optical system such as a laser printer, a digital copying machine, and a laser facsimile, and further relates to a color image forming apparatus that forms a multicolor image.

In recent years, with the advancement of image forming apparatuses, the demand for image quality has increased, and for image forming apparatuses using four basic colors of yellow (Y), magenta (M), cyan (C), and black (B), An electrophotographic image forming apparatus with an increased number of colors has been proposed. (For example, see Patent Documents 1 to 4)

In addition, an optical scanning device of an image forming apparatus for two colors of black and red, which is not the basic four colors, has also been proposed. (For example, see Patent Document 5)

In Patent Documents 1 to 4, in addition to basic four color toners of yellow, magenta, cyan, and black, light color toner (for example, light cyan and light yellow), highly transparent toner (for example, transparent toner), Is the one to which raised toner for stereoscopic (3D) images is added. The four colors of yellow, magenta, cyan, and black are called basic colors, and the other colors are called auxiliary colors or special colors.

The light-colored toner is used to improve the image quality by reducing the graininess of the output image, and the toner with high transparency is sometimes used to improve the glossiness.
The auxiliary color is also used when forming a color that is difficult to reproduce with a mixed color of yellow, magenta, and cyan.

Patent Documents 1 to 5 disclose conventional techniques according to the present invention.
Patent Document 1 discloses a configuration in which six stations (two-side scanning in two directions by a common polygon mirror) are housed in one optical housing of a printer having six colors of toner.
Since all the image forming stations are housed in one optical housing, the auxiliary colors are incorporated into the basic four colors, and the auxiliary colors cannot be made optional.
Patent Document 2 discloses a configuration in which five stations (one-side scanning in only one direction by a common polygon mirror) are housed in one optical housing.
Since all image forming stations are housed in one optical housing, the auxiliary colors are incorporated into the four basic colors, and the auxiliary colors cannot be made optional.

Patent Document 3 discloses a plurality of image forming units for forming toner images of four basic colors on an image carrier and a first optical unit (basic color four station unit) for image exposure on each of the image carriers. And a configuration of a second optical unit (auxiliary color 2 station unit) corresponding to the two auxiliary colors. A configuration is disclosed in which the second optical unit is detachable from the image forming apparatus (auxiliary colors are optional).
Since the polygon scanner is mounted not only on the first optical unit for the four basic colors but also on the second optical unit for the auxiliary color, the cost increases. Further, since the amount of heat generation increases as the power consumption increases, the temperature of the optical unit rises, so that the characteristics of the laser beam that scans the surface to be scanned deteriorates, resulting in deterioration of the output image.

Patent Document 4 includes a multi-beam optical scanning image forming unit that uses four basic colors as LD exposure, and a line scanning image forming unit that exposes one auxiliary color using an LED array in which light emitting points are arranged in a line. A technique of an image forming apparatus is disclosed.
The drive / control system for the multi-beam optical scanning image forming unit and the line scanning image forming unit is complicated, and the apparatus and the control system are expensive.

  Patent Document 5 discloses that an optical box is linearly expanded in an optical scanning device that emits two light beams for black and red with different passing light paths from one optical box in an image forming apparatus of two colors of black and red. A technique for reducing the occurrence of color misregistration due to the expansion and contraction of the optical box accompanying a temperature change by configuring with two housings (first housing and second housing) having different coefficients is disclosed. This is not an optionable configuration in which the deflecting means is attached only to the first casing and the second casing without the deflecting means is detachable.

In recent years, from the viewpoint of environmental measures, there has been an increasing demand for low power consumption (energy saving) for image forming apparatuses. The image forming apparatus disclosed in Patent Document 3 has a device configuration in which an image forming station corresponding to the auxiliary color is added, and power consumption is increased by the added apparatus.
On the other hand, there is a great need for an image forming apparatus using only the four basic colors without requiring the auxiliary colors as described above. In order to meet the diversification of user needs, it is necessary to create a product lineup by separately creating an “image forming device with only four basic colors” and an “image forming device with auxiliary colors”. It tends to be expensive in terms of cost. Therefore, a configuration has been proposed in which an auxiliary color is made optional by using an image forming apparatus having only four basic colors as a base machine (Patent Document 3). By adopting such a configuration, it is possible to separately create “an image forming apparatus having only four basic colors” and “an image forming apparatus with auxiliary colors” without increasing the component cost and capital investment. . Further, after the user purchases the “image forming apparatus having only four basic colors”, when the need for “auxiliary colors” becomes apparent, the “auxiliary colors” can be easily expanded as an option.

In the configurations of the prior arts disclosed in Patent Documents 1 to 4, a structure that cannot be made optional for auxiliary colors, and even if it can be made optional, not only the first optical unit for four basic colors but also the second optical for auxiliary colors. Since the unit is equipped with a polygon scanner, the optical unit temperature rises due to high costs and increased power consumption due to the addition of the polygon scanner, and the characteristics of the laser beam that scans the surface to be scanned deteriorate. As a result, the output image is degraded. There is also a problem that the drive / control system of the optical scanning image forming unit is complicated.

Further, the configuration of the prior art disclosed in Patent Document 5 does not have a configuration that allows the second casing without the deflection means to be attached to and detached from the first casing.

The present invention has been made under such circumstances. An image forming apparatus in which auxiliary colors are added to four basic colors while maintaining high image quality as an image forming apparatus, is based on an image forming apparatus having only four basic colors. The present invention provides an image forming apparatus that can easily make auxiliary colors optional for the four basic colors without increasing the cost and power consumption as in the prior art, with a configuration that makes auxiliary colors optional. Objective.

The present invention is, yellow, magenta, cyan, and a plurality of image bearing bodies corresponding to each of the at least one auxiliary color other than the four basic colors and the four basic colors of black, corresponding to the plurality of image bearing members A light source that emits a plurality of laser beams, at least one optical deflector that deflects the plurality of laser beams corresponding to the plurality of colors by rotating a plurality of deflection reflecting surfaces around a rotation axis, and the optical deflector And a scanning optical system for condensing the laser beam deflected by the laser beam onto the corresponding image carrier, wherein the scanning optical system applies the surfaces of the plurality of image carriers corresponding to the four basic colors. A first portion housed in a first housing that scans with a laser beam, and a second housing that scans the surface of the image carrier corresponding to the at least one auxiliary color with a laser beam. The optical deflector is provided only in the first portion housed in the first housing, and the second housing is detachable from the image forming apparatus. When the second housing is mounted, the laser beam that scans the surface of the image carrier corresponding to the at least one auxiliary color is deflected by the optical deflector and then provided to the first housing. Light emitted from the first window and incident from the second window provided in the second housing, and the light sources corresponding to the four basic colors are provided in the first housing and correspond to the auxiliary color. A light source is provided in the second housing, and a laser beam emitted from the light source corresponding to the auxiliary color is incident on a deflecting reflection surface of an optical deflector provided in the first housing. No. provided in Characterized in that a fourth window opposite of the window portion of the window portion and the third to the first housing.

According to the present invention, while maintaining high image quality as an image forming apparatus, an optional part related to image formation of auxiliary colors can be easily attached to the basic apparatus, and at low cost while maintaining high image quality, It is possible to easily reduce the apparatus power consumption when the auxiliary color is unnecessary. That is, it is possible to provide an image forming apparatus that can easily make auxiliary colors optional for the four basic colors.

It is a figure which shows Example 1 (sub-scanning cross section) of the optical scanning device based on this invention. FIG. 2 is a diagram illustrating an optical scanning device according to a first embodiment (FIG. 2A is a plan view main scanning cross section) and FIG. 2B is a side view. It is a figure which shows the modification (beam synthesis | combination by a beam synthetic | combination means) of Example 1 of the optical scanning device based on this invention. It is a figure which shows Example G1 (example of 5 station type color image forming apparatus) of the image forming apparatus of this invention. FIG. 5 is a diagram illustrating an optical scanning device according to a second embodiment (FIG. 5A is a sub-scanning cross section, and FIG. 5B is a main scanning cross section)). It is a figure which shows the modification (FIG. 6 (a) is a subscanning cross section, FIG.6 is (b) main scanning cutting | disconnection) of Example 2 of the optical scanning device based on this invention. FIGS. 7A and 7B are views showing the image forming apparatus of Example G1 before mounting the auxiliary image forming station according to the present invention, FIG. 7A is a front view before mounting the second housing, and FIG. FIG. FIGS. 8A and 8B are views showing the image forming apparatus of Example G1 after the auxiliary image forming station (second housing) according to the present invention is mounted, in which FIG. 8A is a front view and FIG. 8B is a left side view. FIG. It is a general view which shows Example H1 which is the mounting method of the 2nd housing with respect to the 1st housing of this invention. It is a figure which shows Example H1 which is the mounting method of the 2nd housing with respect to the 1st housing of this invention, and is a positioning pin part enlarged view. FIG. 10 is a view showing a modification of FIGS. 9A and 9B. It is a general view which shows another modification of Example H1 of the mounting method of the 2nd housing with respect to the 1st housing of this invention. It is a supplementary figure which shows another modification of Example H1 of the mounting method of the 2nd housing with respect to the 1st housing of this invention. It is a figure which shows another modification of Example H1 of the mounting method of the 2nd housing with respect to the 1st housing of this invention, and is a positioning pin part enlarged view. It is a figure which shows another modification of Example H1 of the mounting method of the 2nd housing with respect to the 1st housing of this invention, and is a figure which shows a latching | locking part enlarged view. FIGS. 11A and 11B are diagrams illustrating an example G2 of the image forming apparatus after the auxiliary image station (second housing) is mounted, in which FIG. 11A is a front view and FIG. 11B is a left side view. . FIGS. 12A and 12B are diagrams showing another modified example of the embodiment H1 of the mounting method of the second housing with respect to the first housing of the present invention, FIG. 12A is an exploded view, and FIG. FIG. It is a figure which shows Example A1 of adjustment of the attitude | position of a folding mirror in the auxiliary image forming station which concerns on this invention. FIGS. 14A and 14B are diagrams for adjusting the attitude (β direction) of the folding mirror of Example A1 of the present invention, FIG. 14A is an exploded view from the adjustment screw side, and FIG. 14B is an adjustment from the folding mirror side. FIG. It is a figure which shows adjustment (alpha direction) of the attitude | position of the folding mirror of Example A1 of this invention.

Hereinafter, the operation and configuration of an image forming apparatus and an optical scanning device will be described with reference to FIGS.

(Option of auxiliary image forming station of optical scanning device)
As a first embodiment of the present invention, the option of the optical scanning device and the auxiliary image forming station according to the present invention will be described in detail.
1 is a diagram showing a sub-scanning section of an optical scanning device according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a side view and a plan view of a main scanning section of the optical scanning device according to the first embodiment. . As shown in FIGS. 1 and 2, the optical scanning device 103 includes a first housing 101A, a second housing 101B, and a first basic image forming station 102A and an auxiliary image forming station 102B housed in the respective housings. It is configured.

The first housing 101A houses a “basic image forming station 102A” that scans the surfaces of the four photosensitive drums 11Y, 11M, 11C, and 11K with laser beams 16Y, 16M, 16C, and 16K. The subscripts Y, M, C, and K mean configurations related to four basic colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively.
The basic image forming station 102A includes four image stations (station Y, station M, station C, and station K) corresponding to the four basic colors. For example, in the station K, the laser beam 16K emitted from the light source unit 17K shown in FIG. 2 is reflected by the deflection reflection surface of the polygon mirror 15, and the first scanning lens (12L), the folding mirror 14K1, and the second scanning lens. The surface of the photosensitive drum 11K is scanned at a constant speed as a light spot via 13K. The polygon mirror 15 is mounted on a polygon motor (not shown) to form a polygon scanner, and is driven at a high speed (tens of thousands of RPM) by the polygon motor. The same applies to the other stations Y, M and C.

The light source units 17K, 17M, 17C, and 17K that emit the laser beams 16Y, 16M, 16C, and 16K respectively include a light emitting unit such as a semiconductor laser, a coupling lens that couples the laser beam from the light emitting unit, and a cup. It is composed of a cylindrical lens or the like for converting the ringed laser beam into a line image formed in the sub-scanning direction on the deflection reflection surface of the polygon mirror. The semiconductor laser may be a semiconductor laser array or a VCSEL having a plurality of light emitting units. As an alternative to the cylindrical lens, an anamorphic lens or a diffractive optical element having a function of forming an incident laser beam at least in the sub-scanning direction may be used.

The upper side of the first housing 101A is covered with a cover member 103A in which four slit-shaped openings 22Y, 22M, 22C, and 22K are formed. The cover member 103A may be integrated with the first housing 101A.
The laser beams 16Y, 16M, 16C, and 16K pass through the opening. The openings 22Y, 22M, 22C, and 22K are covered with a transparent parallel flat glass (not shown), and can prevent dust from entering from the outside.

(Slit-shaped opening is covered with parallel flat glass / shielding member)
In the case of an image forming apparatus that forms an image on a recording sheet with a total of five auxiliary color toners in addition to the basic four color toners, auxiliary image formation is performed on the left side of the first housing 101A that houses the basic image station 102A. A second housing 101B that houses the station 102B is provided. A slit-shaped opening 21A for allowing a laser beam to pass through the second housing 101B is formed on the left side wall of the first housing 101A. As with the openings 22Y, 22M, 22C, and 22K, the opening 21A is desirably covered with a transparent parallel flat glass (not shown). On the other hand, when the basic image forming station 102A is mounted on an image forming apparatus that forms an image on recording paper with basic four-color toner, the opening 21A is not shown in view of safety (and dust resistance). It is necessary to cover with.

On the other hand, the second housing 101B is disposed on the left side surface side of the first housing 101A. The second housing 101B houses a part of an “auxiliary image forming station 102B” that scans the surface of the photosensitive drum 11S with the laser beam 16S. The subscript S means a configuration of auxiliary colors or special colors.
The laser beam 16S light source unit 17S includes a light emitting unit such as a semiconductor laser, a coupling lens that couples a laser beam from the light emitting unit, and a coupled laser as in the above-described 17Y, M, C, and K. It consists of a cylindrical lens or the like that converts the beam into a line image formed in the sub-scanning direction on the deflecting / reflecting surface of the polygon mirror. The semiconductor laser may be a semiconductor laser array or a VCSEL having a plurality of light emitting units. The laser beam 16S emitted from the light source unit 17S is reflected by the deflecting / reflecting surface of the polygon mirror 15 and passes through the first scanning lens (12L). The laser beam 16S that has passed through the first scanning lens (12L) passes through the slit-shaped opening 21B formed in the left side wall of the second housing 101B, and then passes through the second scanning lens 13S and the folding mirror 14S1. Then, the surface of the photosensitive drum 11S is scanned at a constant speed as a light spot.

Similar to the first housing 101A, the upper side of the second housing 101B is covered with a cover member 103B in which a slit-shaped opening 22S is formed, and the opening 22S is covered with a transparent parallel flat glass (not shown). Yes. The cover member 103B may be integrally formed with the second housing 101B.
The second housing 101B is not to desired to be attached to the first housing 101A as described below.
The second housing 101B may be attached to the main body of the image forming apparatus.
As described above, the opening 21A is provided on the left side wall orthogonal to the arrangement surface of the four openings 22Y, 22M, 22C, and 22K in the cover member 103A of the first housing 101A, and at least one folding mirror (this In the embodiment, since the optical path is turned back by 14S1) and the laser beam 16S is guided to the photosensitive drum 11S, the auxiliary color photosensitive drums 11S are arranged as shown in FIG. As described above, it is possible to arrange the basic four-color photosensitive drums 11Y, 11M, 11C, and 11K in series along the moving direction of the transfer belt 31 of the image forming apparatus 104.
Since they can be arranged in this way, the auxiliary image forming station mounting structure can be simplified, and the optical scanning device can be made thinner and smaller.

(Advantages of deploying the polygon scanner only in the first housing)
In the optical scanning device 103 of FIG. 1, a first housing 101A (basic image forming station 102A) having a polygon scanner such as a polygon mirror 15 is added to a second housing 101B (auxiliary image forming station 102B) not having a polygon scanner. Attached. Since the polygon scanner is a component having a high cost ratio among the components constituting the optical scanning device, the cost can be reduced as compared with the conventional technique of Patent Document 3 including two polygon scanners. In addition, a polygon scanner that is driven to rotate at high speed consumes a large amount of power and generates a large amount of heat. Due to the influence of this heat generation, the temperature inside the optical scanning device rises and the housing member and the optical element are deformed, so that the properties of the laser beam (beam spot diameter, scanning line shape, etc.) on the photosensitive drum deteriorate. This degrades the quality of the output image. The optical scanning device 103 of the present invention is preferable because the conventional polygon scanner disclosed in Patent Document 3 can have a structure in which one of the two is omitted, so that the heat generation amount can be halved. It is a configuration.

The optical path of the laser beam will be described with reference to FIGS.
The laser beams 16Y, 16M, 16C, 16K, and 16S emitted from the light sources 17Y, 17M, 17C, 17K, and 17S are in the basic image forming station in the sub-scanning section with respect to the deflecting and reflecting surface of the polygon mirror 15. For the stations Y, M, C, and K stored in 102A, oblique incidence is performed, and for the station S stored in the auxiliary image station 102B, horizontal incidence is performed.
In the optical scanning device 103 according to the first embodiment, the laser beams 16Y, 16M, 16C, and 16K from the light source units 17Y, 17M, 17C, and 17K in each station are cross-scanned with respect to the deflection reflection surface of the polygon mirror 15. The configuration is “oblique incidence”. For example, in the stations K and C, as shown in FIG. 2, the light source units 17K and 17C overlap each other in the plan view of FIG. 2A, and are shifted in the vertical direction in the side view of FIG. The part 17K is arranged on the upper side, and 17C is arranged on the lower side. The same applies to stations Y and M.
On the other hand, in the station S, the laser beam 16S from the light source unit 17S is configured to be “horizontal incident” in the sub-scan section with respect to the deflecting / reflecting surface of the polygon mirror 15. In the present optical scanning device 103, the light source unit 17S is arranged to be shifted from the light source units 17K and 17C in the main scanning section so that the light source unit 17S does not interfere with the light source units 17K and 17C. As a result, the thickness of the polygon mirror 15 can be reduced, and the cost and speed of the polygon mirror 15 can be reduced.

FIG. 3 is a diagram showing a modified example of the optical scanning device according to the first embodiment, and shows a state of beam synthesis by the beam synthesizing unit. The beam synthesizing unit 18 using a half mirror, a polarization beam splitter, etc. The beam 16S may be combined with the laser beams 16K and 16C.

Further, the optical path of the laser beam of the station S where the laser beam is incident horizontally is configured to pass between the optical paths of the station C and the station K where the laser beam is incident obliquely as shown in FIGS. . Therefore, the dimension in the height direction (Z-axis direction) of the first housing 101A and the second housing 101B can be reduced, and the optical scanning device 103 can be reduced in size / weight and cost. Doo ing.

FIG. 4 shows a 5-station type color image forming apparatus as an embodiment G1 of the image forming apparatus of the present invention.
The optical scanning apparatus 103 including the first housing 101A and the basic image forming station 102A and the second housing 101B and the auxiliary image forming station 102B as described above is applied as an exposure unit of an image forming apparatus using an electrophotographic process. can do.
FIG. 4 shows the main part of a five-station type color image forming apparatus capable of outputting a color image with five color toners. In the basic image forming station 102A, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K. An electrostatic latent image based on image information is formed by laser beams 16Y, 16M, 16C, and 16K, and an image is formed with toners of four basic colors (Y, M, C, and K) by an electrophotographic process (not shown). In the auxiliary image forming station 102B, an electrostatic latent image based on image information is formed on the surface of the photosensitive drum 11S with a laser beam 16S, and an image is formed with auxiliary color toner by an electrophotographic process (not shown). As the auxiliary color, clear (transparent) toner, light color (light black, light cyan, etc.), white toner, raised toner, etc. are used. After superposing these five color toner images on the transfer belt 31, the toner images are transferred to an output paper (recording paper) 33 conveyed by the conveying belt 32. After five color toner images transferred onto the output paper 33 which is fixed / fixed to the output paper 33 by the fixing unit 34, Ru is discharged (output) onto the discharge tray 37.

In FIG. 4, the second housing 101B (auxiliary image forming station 102B) is arranged only on the left side of the first housing 101A (basic image forming station 102A). In addition to the basic housing 101B, a third housing (second auxiliary image forming station) (not shown) is also added on the right side to form a 6-station image forming apparatus arranged on both sides. An auxiliary image can be formed as an option.

(Use of auxiliary color toner)
When printing on colored output paper, it is desirable to form a white background by fixing white toner as an auxiliary color on the lowermost layer on the output paper, and then superimposing basic four color toners on the white background. For this purpose, the auxiliary image forming station 102B may be disposed downstream of the basic image forming station 102A in the moving direction of the transfer belt 31 (arrow 1).

When clear toner is used as an auxiliary color in order to obtain gloss such as a photographic image, the clear toner may be superimposed on the basic four-color toner on the output paper (the clear toner is the uppermost layer). desirable. The same applies to the case where 3D (raised) toner is used as an auxiliary color for surface processing on output paper. In such a case, as shown in FIG. 4, the auxiliary image forming station 102B with respect to the basic image forming stations 102A, have good be arranged on the upstream side in the moving direction of the transfer belt 31 (arrow 1).

(Configuration to maintain printing speed)
The auxiliary image forming station 102B (second housing 101B) is unnecessary for a user who uses an image forming apparatus that forms an image using only basic four-color toner (basic image forming station). When the second housing 101B is configured to be optionally mounted on the right side of the first housing 101A, that is, on the downstream side in the movement direction of the transfer belt 31, the movement distance of the transfer belt 31 is equal to the width of the second housing 101B. Only gets longer. As a result, the first print time becomes long and the print speed is lowered, which is not preferable. Also in this respect, it is desirable that the auxiliary image forming station 102B is disposed upstream of the basic image forming station 102A in the moving direction of the transfer belt 31 (arrow 1). By improving the printing speed, it is possible to shorten the operating time of the image forming apparatus, it is possible to reduce power consumption and that Do.

(Second scanning lens in auxiliary image forming station)
In each of the stations Y, M, C, and K of the basic image forming station 102A, the optical path is folded by folding mirrors (14Y1, 14M1, 14C1, 14K1, etc.). When the folding of the optical path by the folding mirror is developed, the optical paths of the laser beams of the four stations Y, M, C, and K are optically “equivalent” optical systems (on a plane perpendicular to the sub-scan section in FIG. 1). Symmetric shape with respect to a parallel plane and a plane parallel to the sub-scan section. By adopting such a configuration, the four second scanning lenses 13Y, 13M, 13C, and 13K can be shared.

On the other hand, the optical path of the laser beam at the station S of the auxiliary image forming station 102B is “horizontal incidence” as described above. In the case of the configuration shown in FIG. 2, the optical path from the light source unit 17S to the polygon mirror 15 is also included. This is different from the basic image forming station 102A. That is, the station S is not optically “equivalent” to the stations Y, M, C, and K of the basic image forming station 102A. Therefore, for example, when it is necessary to improve the output image quality by using light black, light cyan or the like as an auxiliary image in the auxiliary image forming station 102B in order to express intermediate colors or adjust the color density. In order to obtain optical performance equivalent to that of the basic image forming station at the auxiliary image forming station 102B (station S), the second scanning lens 13S is designed separately from the second scanning lenses 13Y, 13M, 13C, and 13K (shape). )And it is sufficient.

(Acceptable optical performance degradation)
In the case of an image of clear toner or white toner, the influence of image quality deterioration on the quality of the entire output image on the output paper is relatively small. For this reason, when clear toner or white toner is used as the auxiliary color of the auxiliary image forming station 102B, high image quality is often not required as compared with a color image using basic four-color toner. Therefore, the properties of the laser beam on the surface of the photosensitive drum 11S may not be better than the properties of the laser beams on the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K of the basic image forming station 102A. In such a case, the second scanning lens 13S has a different design (shape) from the second scanning lenses 13Y, 13M, 13C, and 13K, and an incident surface of dust-proof glass (not shown) for covering the opening 22S and / or You may manufacture and arrange | position by the "hybrid structure" which formed the lens shape with the resin material on the output surface. Thereby, cost reduction of the 2nd scanning lens 13S (and dustproof glass) can be achieved.
Further, the second scanning lens 13S may not be provided in the optical path of the laser beam 16S of the auxiliary image forming station 102B, and only the folding mirror 14S1 may be provided in the second housing 101B. With such a configuration, it is possible to reduce the cost by omitting the second scanning lens in the auxiliary image forming station, and to reduce the number of parts and the assembly process.

As a second embodiment of the present invention, the option of the optical scanning device and the auxiliary image forming station according to the present invention will be described in detail.
FIG. 5 shows the configuration of the optical scanning device according to the second embodiment of the present invention.
In FIG. 5, the first housing 101A includes a “basic image forming station 112A1” (stations Y and M) sharing the polygon mirror 15A1 and a “basic image forming station 112A2” (stations C and A) sharing the polygon mirror 15A2. A basic image forming station consisting of a total of four stations K) is accommodated. The two basic image forming stations 112A1 and 112A2 have the same optical layout. The station Y includes optical elements such as a light source unit 17Y, a polygon mirror 15A1, a first scanning lens 12A2, a folding mirror (not shown), and (and a photosensitive drum 11Y), and all the optical elements are accommodated in the first housing 101A. Has been. The same applies to the other stations M, C, and K.

An auxiliary image forming station 112B is accommodated in the second housing 101B. The auxiliary image forming station 112B includes optical elements such as a light source unit 17S for the auxiliary color station, a first scanning lens 12B, a folding mirror (not shown), and (and the photosensitive drum 11S). The second housing 101B and the first housing 101A are each formed with a window (not shown) for emitting from the light source unit 17S and entering the polygon mirror 15A2. That is, in the auxiliary image forming station 101B, the basic image forming station 112A2 and the polygon mirror 15A2 are shared. Unlike the first embodiment, not only the first scanning lens 12B and the folding mirror (not shown), but also the light source unit 17S is housed in the second housing 101B.
As described above, since the optical element such as the light source unit 17S, the first scanning lens 12B, and a folding mirror (not shown) is accommodated in the second housing 101B, the light source unit 17S is added to the first housing 101A side. The auxiliary image forming station 112B can be made optional (attached) without performing the above. In other words, after the image forming apparatus for basic four-color toner is shipped from the factory, even if an auxiliary image forming station for auxiliary color toner is to be expanded (optional) at the user's site, the image forming apparatus (MFP or printer) main body is installed. without significant degradation, may incorporate auxiliary image forming station to the image forming apparatus and that Do.

A modification of the second embodiment of the optical scanning device 103 is shown in FIG. 6A shows a sub-scanning sectional view, and FIG. 6B shows a main scanning sectional view. In this modification, the first housing 101A is divided into two sub-housings 101AS1 and 101AS2. Dividing into two sub-housings reduces the size of one sub-housing, so the assembly distance between the housing side wall and the storage components in each sub-housing is relatively reduced and the rigidity is increased by increasing the rigidity. Therefore, it is possible to improve the anti-vibration property for preventing the occurrence of errors due to vibration applied from the above. In addition, when manufacturing by a method such as resin mold molding, it is easy to increase the accuracy with downsizing. Furthermore, by using sub-housings with the same shape, it is possible to reduce the cost due to mass production effects. The presence or absence of the opening on the left side wall of the sub-housing may be formed by processing after resin molding, or may be covered with a shielding member, as necessary.

(Installation method of the second housing 101B)
The polygon mirror 15 (15A2) of the basic image forming station 102A housed in the first housing 101A (101AS1) as shown in FIGS. 1, 2, 5, and 6 is connected to the auxiliary image forming station 102B. In the configuration shared by the optical system, the relative positional relationship of the optical elements (light source unit, cylindrical lens, second scanning lens, folding mirror, etc.) on the auxiliary image forming station 102B side with respect to the polygon mirror 15 (15A2) is high. It is necessary to maintain accuracy. When this relative positional relationship is deteriorated, the scanning line inclination on the surface of the photosensitive drum is generated, and the output image quality is deteriorated such that the beam spot diameter is deteriorated.

To solve this problem,
(1) The second housing is mounted with high accuracy on the first housing.
(2) Further, after the second housing is mounted on the first housing, the position / posture of the optical element inside the auxiliary image forming station is adjusted.
You can take measures against it.
Further, during assembly adjustment, the assembly adjustment may be performed after reducing the temperature difference between the apparatus on the mounting side and the mounting side.
Similar to the technique of Patent Document 3, the scanning optical device for the auxiliary image (special color: light cyan, light magenta) forming station may be mounted on the image forming apparatus main body side. It is necessary to consider the matters that should correspond to changes in assembly accuracy.

When the second housing 101B is mounted inside the image forming apparatus 104, there is a method in which the image forming apparatus main body (for example, the face plates 39F and 39R in FIG. The polygon mirror 15 of the auxiliary image forming station 102B is shared with the polygon mirror 15 of the basic image forming station 102 A. Therefore, in order to maintain optical performance (particularly, scanning line tilt accuracy), the second housing It is necessary to maintain the positional relationship between the first housing 101A and the first housing 101A with high accuracy, but in the case where such a polygon mirror 15 is shared between the basic image forming station and the auxiliary image forming station, both stations are provided. It is difficult to maintain the mounting and fixing position relationship between the two with high accuracy, and this may cause degradation of the output image. To become.

Further, not only the basic image forming station 102A (first housing 101A) but also the image forming apparatus including the auxiliary image forming station 102B (second housing 101B) is transported to the user destination after shipment from the factory, or the user destination. When the “flatness” of the installation surface is not good at the time of installing the image forming apparatus main body, the image forming apparatus main body is distorted, and as a result, the relative positional relationship between the basic image forming station 101A and the auxiliary image forming station 101B is shifted. This causes deterioration of the output image. On the other hand, when the second housing 101B is mounted on the first housing 101A with high accuracy by an optional mounting method of the second housing to the image forming apparatus main body, which will be described later, the auxiliary image forming station 102B displays the image. Since it is not affected by the distortion of the main body of the forming apparatus, there is no possibility that the quality of the output image will deteriorate, and this is a desirable configuration.

(Optional mounting of the second housing to the image forming apparatus main body)
FIG. 7 is a diagram showing a state before the auxiliary image forming station 102B (second housing 101B) is attached to the image forming apparatus 104, and FIG. 8 is a diagram showing a state after the attachment.
A method of mounting the auxiliary image forming apparatus 101B to the image forming apparatus 104 will be described with reference to FIGS. FIG. 7 shows a state in which the image forming apparatus 104 including the basic image forming station 102A for basic four-color toner is shipped from the factory. FIG. 8 shows the second housing 101B (auxiliary image forming) at the user's destination after the purchase. A state where the station 102B) is installed as an option in the image forming apparatus 104 is shown.
As shown in FIG. 7, in the image forming apparatus 104 of Example G1, a front cover 38 is provided on the operator side (front side) of the apparatus main body. The photosensitive drums 11Y, 11C, 11M, and 11K are fixed in a state of being positioned with high accuracy with respect to the face plate 39R that is fixed to the main body frame 40 by welding and 39F that is screwed and fixed. The first housing 101A is placed on a stay member 41 that is bridged and supported by the face plates 39R and 39F.

A case where an auxiliary image forming station 102B as an option is mounted on the image forming apparatus 104 will be described with reference to FIG.
(1) Open the front cover 38 to the front side of the operator.
(2) The face plate 39F screwed to the main body frame 40 is removed.
(3) The photosensitive drum 11S and a “photosensitive unit” including a charging device, a developing device, a cleaning unit and the like (not shown) are assembled to the face plate 39R.
(4) The inner cover 42 screwed to the main body frame 40 is removed.
(5) Mount the second housing 101B. (The specific method will be described later)
(6) The face plate 39F and the inner cover 42 are screwed to the main body frame 40.
Follow the steps.
In such a configuration, the light source unit 17S for the auxiliary image forming station 102B may be provided on the first housing 101A side at the time of assembly in the factory, or the second housing 101B at the user's site. When attaching the light source portion 17S, the first housing 101A may be pulled out toward the front side.
If the optional auxiliary image forming station 102B is not required due to user needs, the second housing 101B and the “photosensitive unit” (not shown) may be removed in the reverse procedure.

An embodiment H1 of a method for mounting the second housing 101B with high accuracy to the first housing 101A will be described.
9A and 9B are views showing a method of mounting the second housing on the first housing 101A, FIG. 9A is an overall view, FIG. 9B is an enlarged view of a positioning pin portion according to the method, and FIG. (C) shows the modification which concerns on Example H1 of this method, respectively. FIG. 9 shows an example of a method for attaching the second housing 101B to the first housing 101A with high accuracy. The light source unit, the first scanning lens, the second scanning lens, the folding mirror, and the like are omitted. 8 shows a state in which the front cover of the image forming apparatus 104 main body is opened on the front side of the operator, that is, the front side of the image forming apparatus. In FIG. 9, the front cover is accessed from the front side of the operator. A method for mounting (screw fastening) the second housing 101B to the first housing 101A will be described.

The mounting method described in the present embodiment H1 can be applied not only to the optical scanning device shown in FIGS. 1 and 2, but also to any of the optical scanning devices shown in FIGS.
In FIG. 9, two positioning pins 51a are arranged in the vertical direction on the rear side wall 61B of the second housing 101B. The two positioning pins 51a are respectively inserted into reference holes (round holes 52a and long holes 52b) formed in the protruding portion 58A protruding from the left end of the rear side wall 61A of the first housing 101A. The positioning pin 51a and the reference holes (52a, 52b) can be fitted with high accuracy.
Two screw holes 54 are arranged in the vertical direction on the left side of the front side wall 63A of the first housing 101A. Two fastening screws 51 are passed through the two through holes 53 formed in the protruding portion 57B protruding from the right end of the front side wall 63B of the second housing 101B with respect to the two screw holes 54, and screwed. Conclude. Screw fastening operation, it is possible to access from the image forming apparatus main body front side, workability Ru good der.
With such a configuration, the second housing 101B can be positioned and mounted with high accuracy with respect to the first housing 101A.

As shown in FIG. 9B, a positioning pin 51c is provided at an intermediate portion or the like of the two screw holes 54 of the first housing 101A, and the second housing is provided so as to correspond to the positioning pin 51c. A reference hole (round hole) 52c is formed at the center of the projecting portion 57B of 101B (intermediate portion of the two through-holes 53), and the two are fitted with high precision so that they are mounted with higher precision. can do.

In addition, unlike FIGS. 9A and 9B, as shown in FIG. 9C, positioning pins 51a and 51b are provided on the protruding portion 58A of the first housing 101A, and the second housing 101B has a reference. The holes 52a and 52b may be formed.
Further, the positioning pins may be one or three or more instead of two. Further, the positioning pin does not need to be integrally processed with the first housing 101A, and may be configured to assemble a separate part.

(Advantages of screw fastening only the front side)
As shown in FIG. 3 etc., the light source part inside the first housing 101A is arranged on the rear side wall 61A side. On the other hand, in the image forming apparatus 104 shown in FIG. 8, the rear side walls 61A and 61B shown in FIG. 9 are positioned by positioning pins and reference holes, and the front side walls 63A and 63B are screwed. For the positioning pin, the relative axial relationship of the pin is not restricted with respect to the reference hole (round hole 52a), and relative to the reference hole (long hole 52b) in the axial direction of the pin and the longitudinal direction of the elongated hole. The positional relationship is not constrained.
As described above, the screw fastening portion is not provided in the vicinity of the light source portion, and is configured to be restrained by the positioning pin and the reference hole, so that it can freely move in a predetermined direction. Therefore, even when the second housing 101B is screwed to the first housing 101A, the deformation on the side of the rear side wall 61A where the light source unit is provided is suppressed, and the light source unit is not likely to be displaced. As in the case of the optical scanning device (first housing 101A) shown in FIG. 9, when the shape of the left side wall 62A (rectangular shape) is larger in the depth direction of the image forming apparatus 104 than in the height direction. Is particularly effective. Therefore, it is possible to avoid the posture adjustment of the optical element such as the folding mirror, or to reduce the man-hours. As a result, there is an effect that the basic four color output images of the basic image forming station in the first housing 101A are not deteriorated.
Further, even when the temperature inside the apparatus rises due to the driving of the image forming apparatus main body, the deformation on the rear side wall 61A side of the first housing 101A can be suppressed. In particular, as in the case where the first housing 101A is made of aluminum and the second housing 101B is made of resin (including resin containing several tens of percent glass fiber or carbon fiber for high rigidity), both even when the amount of expansion of heat are different, Ru can suppress the degradation of the output image quality.

(When fastening all parts with screws)
As shown in FIG. 9C, when the second housing 101B (auxiliary image forming station 102B) is optionally installed, all the locations may be screwed. In particular, when the rigidity of the first housing 101A is sufficiently secured, or when the mounting posture of the optical element such as the light source portion is not easily affected by the screw fastening, the positioning pin as described above is used for predetermined. Without securing the degree of freedom of movement in this direction, there is no effect on the optical performance even if it is firmly fixed by screw fastening.
In addition, when the auxiliary image forming station 102B is not installed as an option at the user's site, but is mounted within the assembly process at the assembly factory, it is not necessary to perform a screw fastening operation from the front side of the image forming apparatus main body.
In the rear side walls 61A and 61B of the configuration shown in FIG. 9A or 9B, a screw hole 54 is provided in the middle portion of the positioning pins 51a and 51b of the second housing 101B, A through hole 52d is provided at an intermediate portion between the reference holes 52a and 52b of the protruding portion 58A of one housing 101A. By fastening with the fastening screw 51 to the screw hole 54 through the through hole 52d, it can be firmly fixed.

(Ensure dust resistance)
As shown in FIG. 9A, when the second housing 101B is attached to the first housing 101A, a gap is generated on the joint surface (the left side wall 62A and the right side wall 62B). Through this gap, dust may enter from the outside into the first housing 101A and the second housing 101B through the slit-shaped opening 21A and the opening 21B, respectively.
Intrusion of dust can be avoided by covering the slit-shaped opening with dust-proof glass as described above [covering the slit-shaped opening with parallel flat glass / shielding member]. Alternatively, instead of the dustproof glass, a dustproof member such as polyurethane foam or polyethylene foamed sponge may be provided in the gap between the joint surfaces. Lower cost than dust-proof glass.

(Method 2 for mounting the second housing to the first housing with high accuracy)
FIGS. 10A, 10B, 10C, and 10D are views showing a modification of the embodiment H1 of the mounting method of the second housing with respect to the first housing. Ru der those mounting the housing to the first housing.
10 (a) and 10 (b), FIG. 10 (a) is an overall view, and FIG. 10 (b) is a supplementary view, showing an example of a configuration in which the second housing 101B is mounted from the left side of the image forming apparatus main body. is there. In this case, by providing not only the “front cover 38” shown in FIG. 7B but also a “side cover” (not shown) on the left side surface of the image forming apparatus 104 main body shown in FIG. The workability of the screw fastening work can be improved.
Two locking portions 55 arranged in the vertical direction are formed at the rightmost end portion of the rear side wall 61B of the second housing 101B of FIG. Two positioning holes 56 corresponding to the locking portions 55 are formed in the protruding portion 58A at the left end portion of the rear side wall 61A of the first housing 101A. In a state where the two locking portions 55 are fitted in the two positioning holes 56, the two fastening screws 51 are passed through the two through holes 53 of the protruding portion 57B of the second housing 101B, so that the first Are fastened to the two screw holes 54 of the housing 101A.

Further, by fitting the positioning pin 51c and the reference hole (round hole) 52c as shown in FIG. 10C with high accuracy, the second housing can be mounted with high accuracy on the first housing. It becomes possible to do.
Further, as shown in FIG. 10D, the positioning hole 56 is not a rectangular shape but a key hole shape (for example, a shape obtained by rotating a convex hole by 90 degrees), and a locking member 55 is formed by a spring member such as a leaf spring 64. By adopting a structure that presses against the first housing 101A, the adhesion between the side walls of the first housing 101A and the second housing 101B can be improved, and the positioning accuracy of both can be improved. .
By adopting such a configuration, it is possible to mount the second housing 101B without affecting the deformation (particularly, the light source unit) of the first housing 101A as shown in the second embodiment. It becomes.
If the deformation of both housings is small, the back side of the image forming apparatus of both housings may be screwed and fixed similarly to the front side.

(Another embodiment of a method for mounting the second housing 101B with high accuracy to the first housing 101A)
FIG. 11 is a diagram illustrating an embodiment G2 of the image forming apparatus, and the state of the first housing 101A (basic image forming station 102A) of the second housing 101B (auxiliary image forming station 102B) in the image forming apparatus 104 after the apparatus. FIG. 12 is an exploded view (a) showing assembly in a factory, and a view showing an assembled state.
The image forming apparatus 104 in FIG. 11 is different from the image forming apparatus 104 in FIG. 4 in that the optical scanning device (the first housing 101A and the second housing 101B) is located above five photosensitive members such as the photosensitive drum 11S. Has been deployed. In the case of the image forming apparatus having such a configuration, as shown in FIG. 11B, by opening the upper cover 38b upward, the optical scanning devices in the first housing 101A and the second housing 101B are viewed from above. Ru can be accessed.

An embodiment H2 of a method for mounting the second housing 101B to the first housing 101A housed in the image forming apparatus 104 will be described with reference to FIG. On the back side of the image forming apparatus 104, the first housing and the second housing are positioned with high accuracy by the locking portion and the positioning hole having the same configuration as in FIG. On the front side of the image forming apparatus 104, the housings are positioned with high accuracy by fitting the positioning pins 51 with the reference holes 52c with high accuracy. In this state, the screw is fastened and fixed by two fastening screws.

In addition, as described above, the screw fastening operation is accessed from the upper side of the image forming apparatus 104, so that workability by an automatic machine or an operator is improved even during assembly in a factory, which is a preferable mode. .

When the deformation of both housings is small, the back side of the image forming apparatus 104 may be screwed and fixed as in the case of the front side as described above.

(Adjustment of optical elements inside the second housing (auxiliary image forming station))
An embodiment A1 for adjusting the posture of the folding mirror 14S1 in the auxiliary image forming station 102B will be described with reference to FIGS. FIG. 13 is a diagram illustrating adjustment of the posture of the folding mirror 14S1 in the auxiliary image forming station 102B.
By adopting the configuration of the first housing 101A and the second housing 101B, the second housing 101B can be optionally attached to the first housing 101A with high accuracy.
However, due to the influence of the processing error of the second housing 101B, etc., the optical elements on the auxiliary image forming station side (light source unit, cylindrical lens, second scanning lens, folding back) with respect to the polygon mirror 15 housed inside the first housing 101A. The relative positional relationship between the mirror and the like may not be good. In particular, when the attitude of the folding mirror changes, image degradation such as “color shift” in which toner images do not overlap with high accuracy in the output image occurs.
Therefore, it is desirable to provide an adjustment mechanism for adjusting the posture of the folding mirror 14S1 inside the second housing 101B.

This adjustment mechanism
(1) Use actuator means such as a stepping motor.
(2) Manually adjust the adjustment screw etc. with an adjusting screw driver.
Or the like. After the second housing 101B is mounted on the image forming apparatus (first housing 101A), adjustment work is performed.
As shown in FIG. 13, in order to correct the position of the scanning line on the photosensitive drum 11S (the circumferential position of the photosensitive drum), the folding mirror 14S1 is rotated in the direction of arrow β in the figure to perform scanning. to correct the inclination of the line has good if rotated in the direction of arrow α in the figure the folding mirror 14S1.

In the case of manual adjustment of the adjustment mechanism (2), it is necessary to consider the access direction of the screw driver for adjustment in order to facilitate adjustment work. For example, in the case of the configuration shown in FIG. 9, it is possible to access from the front side of the main body of the image forming apparatus 104 as in the fastening operation of the fastening screw 51, and in the case of the configuration shown in FIG. It is desirable to make it accessible from the left side.

14 is a diagram showing an example of a configuration for adjusting the posture of the folding mirror 14S1 in the auxiliary image station 102B in the β direction shown in FIG. 13, and FIG. 14 (a) is a view from the adjustment screw 73 side. FIG. 5B is a view from the laser beam incident side to the folding mirror 14S1. This is an example of application to the optical scanning device 103 shown in FIG.
In FIG. 14, support portions 71a and 71b are provided on the front side and the back side of the bottom surface of the second housing 101B, and a holding portion 72 for screwing the adjustment screw 73 is provided in the center portion. The receiving portions 74a, 74b, and 74c of the folding mirror 14S1 are supported at the three points of the supporting portions 71a and 72b and the adjusting screw 73. As shown by the arrow in FIG. 14B, the adjustment screw 72 is pulled out using a tool such as an adjustment screw driver through the through hole 76 formed in the central portion of the left side wall 75 of the second housing 101B. By pushing, the rotation angle of the folding mirror 14S1 in the β direction can be adjusted.

15 similarly supports the α direction of the folding mirror 14S1 as shown in FIG. 15 by supporting the receiving portions 74a and 74b with support portions 71a and 72b formed in a second housing (not shown), and the receiving portion 72c. By using a configuration that is supported by an adjustment screw (not shown), the folding mirror 14S1 can be rotationally adjusted in the α direction in FIG.

  As described above, the image forming apparatus and the color image forming apparatus of the present invention are suitable for reducing power consumption while maintaining high image quality.

DESCRIPTION OF SYMBOLS 101A ... 1st housing, 101B ... 2nd housing, 102A, 112A1, 112A2 ... Basic image forming station, 102B, 112B ... Auxiliary image forming station, 103 ... Optical scanning device, 104 ... Image forming device, 11Y, 11M, 11C, 11K, 11S ... photosensitive drum, 12L, 12R ... first scanning lens, 13Y, 13M, 13C, 13K, 13S ... second scanning lens, 14Y1, 14M1, 14C1, 14K1, 14S1 ... folding mirror, 15, 15A1 , 15A2 ... Porogon mirror, 16Y, 16M, 16C, 16K, 16S ... Laser beam, 17Y, 17M, 17C, 17K, 17S ... Light source part, 18 ... Beam combining means, 21A, 21B ... Opening part, 22Y, 22M, 22C, 22K, 22S ... opening, 31 ... intermediate transfer base 32 ... Conveying belt, 33 ... Output paper (recording paper), 34 ... Fixing device, 35 ... Transfer belt cleaning device, 36 ... Paper feed tray, 37 ... Paper discharge tray, 38 ... Front cover, 39F, 39R ... Face plate 40 ... Body frame (exterior cover)

Japanese Patent Laid-Open No. 2005-104045 JP 2007-144746 A JP 2007-171498 A JP 2007-171493 A JP 2005-17601 A

Claims (8)

Yellow, magenta, cyan, and a plurality of image bearing bodies corresponding to each of the at least one auxiliary color other than the four basic colors and the four basic colors of black, the plurality corresponding to the plurality of image bearing members Leh Zabi A light source for emitting a beam, at least one optical deflector for deflecting the plurality of laser beams corresponding to the plurality of image carriers by rotating a plurality of deflecting reflecting surfaces around a rotation axis, and the optical deflector An image forming apparatus including a scanning optical system that condenses the laser beam deflected by the laser beam on a corresponding image carrier,
The scanning optical system corresponds to the first portion housed in a first housing that scans the surfaces of the plurality of image carriers corresponding to the four basic colors with a laser beam, and the at least one auxiliary color. A second portion housed in a second housing that scans the surface of the image carrier with a laser beam,
The optical deflector is provided only in the first portion housed in the first housing,
The second housing is configured to be detachable from the image forming apparatus,
When the second housing is mounted, the laser beam that scans the surface of the image carrier corresponding to the at least one auxiliary color is deflected by the optical deflector, and then is provided in the first housing. Emanating from the window,
Incident from the second window provided in the second housing ,
The light sources corresponding to the four basic colors are provided in the first housing,
A light source corresponding to the auxiliary color is provided in the second housing,
A third window provided in the second housing for allowing a laser beam emitted from a light source corresponding to the auxiliary color to enter a deflection reflection surface of an optical deflector provided in the first housing; An image forming apparatus , wherein a fourth window portion facing the third window portion is provided in the first housing . The image forming apparatus according to claim 1, wherein
The laser beam emitted from the light source corresponding to the auxiliary color is incident on the deflecting / reflecting surface of the optical deflector in a sub-scan section in a state parallel to a plane perpendicular to the rotation axis of the optical deflector. An image forming apparatus characterized by the above. The image forming apparatus according to claim 1, wherein
The second housing is accessed from a cover provided on the left side, right side, or upper side of the main body of the image forming apparatus, and mounting work is performed on the first engagement portion provided in the first housing. An image forming apparatus, comprising: a second engaging portion that is possible. The image forming apparatus according to claim 3 .
The light source is disposed on the back side in the sub-scanning direction in the image forming apparatus main body,
The first engaging portion includes a first positioning reference portion formed in the vicinity of a wall surface on the back side of the first housing, and the second engaging portion is connected to the first positioning reference portion. A second positioning reference formed on the corresponding second housing,
An image forming apparatus, wherein the first housing and the second housing are screwed and fixed on the front side of the image forming apparatus main body . The image forming apparatus according to any one of claims 1 to 3 ,
An image forming apparatus capable of correcting a position and an inclination of a scanning line on the image carrier corresponding to the auxiliary color by adjusting a posture of a folding mirror held in the second housing. . The image forming apparatus according to any one of claims 1 to 5 ,
Forming the four basic color toner images on the image carrier;
A color image forming apparatus, wherein the toner image formed on the image carrier is superposed on a transfer belt and then transferred onto an output medium for output . The image forming apparatus according to claim 6 .
The auxiliary color toner is a transparent clear toner,
The clear toner is the uppermost layer of a plurality of toner images that overlap on the output medium.
A color image forming apparatus. The image forming apparatus according to claim 6 .
The color image forming apparatus , wherein the image carrier corresponding to the auxiliary color toner is arranged on the most upstream side in the moving direction of the transfer belt .

Images