JP5098431B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an exposure apparatus that performs optical writing in an image forming apparatus such as a printer or a copying machine.

  2. Description of the Related Art An electrophotographic color image forming apparatus such as a printer or a copying machine is known in which a photosensitive drum and an exposure device are arranged for each color. In such a color image forming apparatus, each exposure device scans and exposes each photosensitive drum with a laser beam modulated in accordance with image data for each color, and therefore the exposure position on the photosensitive drum in each exposure device is set. It is necessary to set in advance with high accuracy. Therefore, the exposure position on the photosensitive drum in each exposure apparatus is adjusted in the manufacturing process (for example, refer to Patent Document 1).

JP 2005-156914 A

  Here, since it is necessary to adjust the exposure of the laser light for each color on the photosensitive drum, the operation takes time. In the conventional configuration, it is difficult to improve the workability.

  An object of the present invention is to provide an image forming apparatus capable of easily adjusting an exposure apparatus.

  An image forming apparatus to which the present invention is applied includes a plurality of image carriers, an exposure device that emits a plurality of light beams corresponding to the plurality of image carriers, and scans and exposes the plurality of image carriers, and a rotation A holding member that holds the exposure apparatus, a first adjusting unit that adjusts one of the plurality of light beams emitted from the exposure apparatus, and the rotation shaft of the holding member And a second adjusting means for adjusting a plurality of light beams by rotating the holding member around the center.

Here, the number of the first adjusting means may be smaller than the number of the plurality of light beams emitted from the exposure apparatus.
In this case, the exposure apparatus emits three light beams, and one central light beam among the three light beams emitted from the exposure apparatus is adjusted by the first adjusting means. It can be. The exposure apparatus emits four light beams, and two light beams excluding the light beams at both ends of the four light beams emitted from the exposure apparatus are adjusted by the first adjusting means. Can be characterized. The exposure apparatus emits five light beams, and the rotation axis of the holding member is positioned in the vicinity of the light beam at one end of the five light beams emitted from the exposure apparatus. The three light beams excluding the light beams at both ends of the five light beams emitted from the exposure apparatus are adjusted by the first adjusting means. The exposure apparatus emits five light beams, and the rotation axis of the holding member is positioned in the vicinity of one central light beam among the five light beams emitted from the exposure apparatus, Of the five light beams emitted from the exposure apparatus, three light beams excluding the light beams at both ends are adjusted by the first adjusting means.

  The image forming apparatus to which the present invention is applied includes an optical scanning device that emits a plurality of light beams to be scanned and exposed on a scanned object, and a rotating shaft, and the optical scanning corresponding to the plurality of scanned objects. A holding member for holding the apparatus, an apparatus main body to which the plurality of scanned objects are attached, and the holding member is attached via the rotating shaft of the holding member, and the rotating shaft of the holding member as a center. And adjusting means for adjusting the optical scanning device with respect to the plurality of scanned objects by rotating the holding member.

  Here, the optical scanning device emits three light beams including a Y color, and the Y color light beam among the three light beams is positioned between the other two light beams. can do.

According to the first aspect, the adjustment operation of the exposure apparatus can be easily performed.
According to claim 2, it is possible to simply configure a mechanism for adjustment.
According to the third aspect, it is possible to suppress the deviation in the sub-scanning direction that occurs when the holding member is rotated by the second adjusting means.
According to claim 4, it is possible to halve the number of first adjusting means.
According to the fifth aspect, even when there is a spot color, the spot color can be adjusted simultaneously with other colors.
According to the sixth aspect, even when there is a special color, it becomes possible to adjust the special color simultaneously with other colors, and a shift in the sub-scanning direction that occurs when the holding member is rotated by the second adjustment means. It becomes possible to suppress.
According to the seventh aspect, the adjustment operation of the exposure apparatus can be easily performed.
According to the eighth aspect, it is possible to omit a mechanism for individually adjusting the Y color located at the center of the three light beams.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating an example of a configuration of an image forming apparatus 1 according to the first embodiment. An image forming apparatus 1 shown in FIG. 1 is a so-called tandem type digital color printer using an electrophotographic system. The image forming apparatus 1 includes an image forming process unit 70 that forms an image corresponding to the image data of each color, a control unit 80 that controls the operation of the entire image forming apparatus 1, and a personal computer (PC) 3 or a scanner, for example. An image processing unit 81 that performs predetermined image processing on the image data received from the image reading device 4 and the like, and a main storage unit 82 realized by, for example, a hard disk (Hard Disk Drive) in which processing programs, image data, and the like are stored. And.

In the image forming process unit 70, four image forming units 10Y, 10M, 10C, and 10K (hereinafter also collectively referred to as “image forming unit 10”) are arranged in parallel at regular intervals in the vertical direction (substantially vertical direction). . The image forming unit 10 develops a photosensitive drum 11 as an image holding member, a charging roll 12 that charges the surface of the photosensitive drum 11, and an electrostatic latent image formed on the photosensitive drum 11 with each color toner. A developing unit 13 and a drum cleaner 14 for cleaning the surface of the photosensitive drum 11 after transfer are provided.
Each image forming unit 10 is configured to be detachable from the main body of the image forming apparatus 1. For example, when the toner in the developing device 13 is consumed or the photosensitive drum 11 reaches the end of its life, It is exchanged in units of 10 image forming units.

The charging roll 12 is composed of a roll member in which a conductive elastic body layer and a conductive surface layer are sequentially laminated on a conductive metal core such as aluminum or stainless steel. Then, a charging bias voltage is supplied from a charging power source (not shown), and the surface of the photosensitive drum 11 is uniformly charged at a predetermined potential while being driven to rotate with respect to the photosensitive drum 11.
The developing device 13 holds a two-component developer composed of yellow (Y), magenta (M), cyan (C), and black (K) toners and a magnetic carrier in each of the image forming units 10, and is photosensitive. The electrostatic latent image formed on the body drum 11 is developed with each color toner.
The drum cleaner 14 brings a plate-like member formed of a rubber material such as urethane rubber into contact with the surface of the photosensitive drum 11 to remove toner, paper dust, and the like attached on the photosensitive drum 11.

Further, the image forming apparatus 1 according to the present embodiment is provided with a laser exposure unit 20 as an example of an exposure unit (exposure apparatus) that exposes the photosensitive drum 11 provided in each image forming unit 10. ing. The laser exposure device 20 acquires image data for each color from the image processing unit 81, and the laser light (light beam) controlled to be turned on based on the acquired image data, on the photosensitive drum 11 of each image forming unit 10. Are respectively subjected to scanning exposure.
Further, a paper transport belt 30 that transports the paper P that is a recording material (recording paper) is disposed so as to move in contact with the photosensitive drum 11 of each image forming unit 10. The paper transport belt 30 is formed of a film-like endless belt that electrostatically attracts the paper P. Then, a paper transport path M1 is formed that is stretched around the drive roll 32 and the idle roll 33 and circulates between the drive roll 32 and the idle roll 33, and transports the paper P from the lower side to the upper side in the substantially vertical direction. Yes.

Transfer rolls 31 are arranged at positions facing the respective photosensitive drums 11 inside the paper transport belt 30. Each transfer roll 31 forms a transfer electric field with the photosensitive drum 11, so that each color toner image formed by each image forming unit 10 is formed on the paper P held and transported by the paper transport belt 30. Transfer sequentially. Further, on the outer side of the paper conveying belt 30 and on the downstream side of each transfer roll 31, a static elimination lamp 15 for eliminating the static charge of the photosensitive drum 11 after the transfer is provided.
An adsorption roll 34 that charges the paper transport belt 30 is disposed at the most upstream portion of the paper transport belt 30 on the photosensitive drum 11 side. The surface of the paper transport belt 30 is electrostatically attracted to the paper P by being charged to a predetermined potential by the suction roll 34.
A fixing device 40 is provided on the downstream side of the paper transport belt 30 along the paper transport path M1 to perform a fixing process using heat and pressure on an unfixed toner image on the paper P.

Further, as a paper transport system other than the paper transport belt 30, a paper storage section 50 that stores the paper P and a paper P stored in the paper storage section 50 are taken out at a predetermined timing and transported to the paper feed side. A pickup roll 51, a conveyance roll 52 that conveys the paper P fed by the pickup roll 51, and a registration roll 53 that sends the paper P to the paper conveyance belt 30 in accordance with an image forming operation are provided.
On the other hand, on the paper discharge side, a paper discharge roll 54 that conveys the paper P fixed by the fixing device 40 is provided. Further, on the paper discharge side, in the case of single-sided printing, the paper P is discharged toward the paper discharge unit 90 provided at the upper part of the apparatus main body, and in the case of double-sided printing, it is directed to the paper discharge unit 90 at a predetermined timing. A reversing roll 55 is provided that feeds the paper P, one side of which has been fixed by the fixing device 40, toward the double-sided conveyance path M2 by reversing from the rotating direction. In addition, the double-sided conveyance path M2 is provided with a plurality of conveyance rolls 56 along the double-sided conveyance path M2.

  In the image forming apparatus 1 of the present embodiment, the image forming process unit 70 performs an image forming operation under the control of the control unit 80. That is, the image data input from the PC 3 or the image reading device 4 is subjected to predetermined image processing by the image processing unit 81 and supplied to the laser exposure unit 20. For example, in the black (K) image forming unit 10 </ b> K, the surface of the photosensitive drum 11 uniformly charged at a predetermined potential by the charging roll 12 is based on the image data from the image processing unit 81 by the laser exposure unit 20. Then, scanning exposure is performed with the laser light whose lighting is controlled, and an electrostatic latent image is formed on the photosensitive drum 11. The formed electrostatic latent image is developed by the developing device 13, and a black (K) toner image is formed on the photosensitive drum 11. Similarly, in the image forming units 10Y, 10M, and 10C, yellow (Y), magenta (M), and cyan (C) toner images are formed.

On the other hand, when the formation of each color toner image in each image forming unit 10 is started, the paper P taken out from the paper storage unit 50 is supplied to the paper transport belt 30 by the registration roll 53 in accordance with the toner image formation timing. Is done. The surface of the paper transport belt 30 is charged to a predetermined potential by the suction roll 34. As a result, the paper P is electrostatically attracted onto the paper transport belt 30 and is transported along the paper transport path M1 by the paper transport belt 30 that circulates and moves in the direction of the arrow in FIG. In the middle of the process, the color toner images are sequentially transferred onto the paper P by the transfer electric field formed by the transfer roll 31.
The sheet P on which each color toner image is electrostatically transferred is peeled from the sheet conveying belt 30 downstream of the image forming unit 10K and conveyed to the fixing device 40. When the paper P is conveyed to the fixing device 40, the unfixed toner image on the paper P is fixed to the paper P by receiving a fixing process using heat and pressure. The paper P on which the color toner images are fixed is stacked on a paper discharge unit 90 provided in a discharge unit of the image forming apparatus 1. On the other hand, during double-sided printing, the same image forming operation is performed again via the double-sided conveyance path M2, and then the paper is stacked on the paper discharge unit 90.

Next, the laser exposure device 20 of the present embodiment will be described.
FIG. 2 is a side view illustrating a schematic configuration of the laser exposure device 20 of the present embodiment. As shown in FIG. 2, the laser exposure device 20 includes a light source 21 composed of, for example, four semiconductor lasers. Furthermore, as an optical member, four collimator lenses 22 provided corresponding to each laser beam from the light source 21, a cylinder lens 23, a rotating polygon mirror (polygon mirror) 24 formed of, for example, a regular hexagonal plane, A plurality of folding mirrors 25, a polygon mirror side lens (not shown) constituting one of the fθ lenses, and four exit side lenses 26K, 26C, 26M, and 26Y constituting the other of the fθ lenses are provided. Further, the laser exposure device 20 is configured in a housing 27 as an example of a holding member, thereby suppressing leakage of laser light to the outside and adhesion of dust or the like to each optical member. Further, the laser exposure device 20 includes a support shaft (rotary shaft) 28 provided integrally with the upper portion of the housing 27 for installation in the image forming apparatus 1, and emission side lenses 26K, 26C, 26M, and 26Y. And a lens fixing frame 29 constituting a part of a holding member for fixing the lens.

In the laser exposure device 20 of the present embodiment, the four divergent laser beams emitted from the light source 21 are converted into parallel beams by the collimator lenses 22 and are converted by the cylinder lens 23 having a refractive power only in the sub-scanning direction. In the vicinity of the deflection reflection surface 24a of the polygon mirror 24, an image is formed as a long line image in the main scanning direction. Each laser beam is reflected by the deflecting / reflecting surface 24a of the polygon mirror 24 that rotates at a high speed at a constant speed, and is scanned at a constant angular velocity.
Each laser beam passes through a polygon mirror side lens that constitutes an fθ lens, and is redirected toward the surface of the photosensitive drum 11 by a plurality of folding mirrors 25, and is emitted from the exit side lenses 26K, 26C, 26M, and 26Y. The surface of the photosensitive drum 11 of the image forming unit 10 is scanned and exposed. Here, the polygon mirror side lens and the emission side lenses 26K, 26C, 26M, and 26Y constituting the fθ lens have a function of equalizing the scanning speed of the laser light spot on the photosensitive drum 11, respectively. Yes.
Further, the above-described line image is formed in the vicinity of the deflecting / reflecting surface 24a of the polygon mirror 24, and the fθ lens links the light spot on the surface of the photosensitive drum 11 with the deflecting / reflecting surface 24a as an object point in the sub-scanning direction. Since this image is formed, this scanning optical system has a function of correcting the tilting of the deflecting / reflecting surface 24a.

  In such a laser exposure device 20, the laser beams LK, LC, LM, and LY emitted from the emission side lenses 26K, 26C, 26M, and 26Y are photoconductive drums of the image forming units 10K, 10C, 10M, and 10Y, respectively. 11 is subjected to scanning exposure. Therefore, main scanning on the photosensitive drum 11 is performed so that the laser beams LK, LC, LM, and LY scan predetermined exposure positions of the photosensitive drum 11 provided in the image forming units 10K, 10C, 10M, and 10Y, respectively. The exposure position in the direction and the sub-scanning direction is set in the manufacturing process at the factory. The exposure position is set mainly by adjusting the set angle of each folding mirror 25. However, the exposure positions on the photosensitive drum 11 in the main scanning direction and the sub-scanning direction need to be set with extremely high accuracy. Therefore, in the final stage of setting the exposure position, the laser exposure device 20 is installed in the measuring apparatus, and the laser light exposure position is actually emitted from the exit side lenses 26K, 26C, 26M, and 26Y. While the angle is measured, the set angles of the exit side lenses 26K, 26C, 26M, and 26Y are finely adjusted, and adjustments are made to match the design values. Then, the exit side lenses 26K, 26C, 26M, and 26Y are fixed to the housing 27 in a state where the exposure position finally matches the design value. Thereby, the exposure positions in the main scanning direction and the sub-scanning direction in the laser exposure device 20 are set with high accuracy.

3A, 3B, and 3C are diagrams for explaining the magnification adjustment of the laser beams LK, LC, LM, and LY. 3A to 3C are side views showing the positional relationship between the laser exposure device 20 and the four photosensitive drums 11, and FIG. 3B is a side view showing the four photosensitive drums 11 as a laser exposure device. It is the front view seen from 20 side.
As shown in FIG. 3A, when the photosensitive drums 11 are irradiated with laser beams LK, LC, LM, and LY (see FIG. 3A) from the laser exposure device 20, each of the photosensitive drums 11 is scanned. Lines SK, SC, SM, and SY (see FIG. 3A (b)) are formed. In the case shown in FIG. 3A, the positions of the scanning lines SK, SC, SM, and SY with respect to the virtual reference line B vary, and magnification adjustment is necessary. Note that the magnification adjustment mentioned here refers to adjustment of the positional deviation of the photosensitive drum 11 in the left-right direction (axial direction) and adjustment of the scanning width (the length of the scanning lines SK, SC, SM, SY).

Here, a configuration necessary for the magnification adjustment will be described.
As shown in FIG. 3B (a), individual adjustment mechanisms (first adjustment means) 110C and 110M are attached to both sides of the folding mirror 25 of the laser exposure device 20. The individual adjustment mechanism 110C is for adjusting only the scanning line SC, and the individual adjustment mechanism 110M is for adjusting only the scanning line SM. More specifically, a mechanism for adjusting the scanning lines SK and SY is not attached to the housing 27. In other words, the present embodiment is configured such that the scanning lines SC and SM can be individually adjusted while the scanning lines SK and SY cannot be individually adjusted. In other words, the number of individual adjustment mechanisms 110C and 110M is smaller than the number of scanning lines SK, SC, SM, and SY or laser beams LK, LC, LM, and LY. Note that the individual adjustment mechanisms 110C and 110M can be configured using a well-known and commonly used technique. In this case, the color K closest to the support shaft 28 is set as the reference color. In the magnification adjustment described later, other scanning lines can be adjusted based on the magnification value of the reference color.

  The housing 27 of the laser exposure device 20 is provided with an overall adjustment mechanism (second adjustment means, adjustment means) 120. The overall adjustment mechanism 120 includes a support shaft 28, a receiving portion (not shown) that receives the support shaft 28 on the main body side of the image forming apparatus 1 that receives the support shaft 28, and a housing 27 that is opposite to the photosensitive drum 11. The projecting portion 121 is fixed to the side, and the threaded portion 122 has a male screw that is screwed into the female screw formed on the projecting portion 121.

  The lower end of the screw part 122 is in contact with the main body of the image forming apparatus 1. In other words, the screw part 122 is placed on the main body of the image forming apparatus 1. Therefore, when the screw portion 122 rotates with respect to the protruding portion 121, the positional relationship between the protruding portion 121 and the housing 27 with respect to the main body of the image forming apparatus 1 is changed by the feed screw action between the screw portion 122 and the protruding portion 121. As a result, the housing 27 rotates around the support shaft 28. Thus, the rotation center is provided on the side surface of the housing 27 of the laser exposure device 20.

A procedure for adjusting the magnification will be described.
As shown in FIG. 3A (b), the scanning lines SK, SC, SM, and SY vary with respect to the virtual reference line B, and it is necessary to relatively adjust the magnification by individual adjustment and overall adjustment.
First, as shown in FIG. 3B (b), the scanning lines SC and SM are positioned in a trapezoidal region formed by connecting the ends of the scanning lines SK and SY that are parallel to each other. Using the individual adjustment mechanisms 110C and 110M, the lengths and positions of the scanning lines SC and SM are adjusted (individual adjustment). In the trapezoid shown in FIG. 3B (b), the upper base is the length of the scanning line SY, and the lower base is the length of the scanning line SK.

When the individual adjustment is completed, the overall adjustment is performed. That is, as shown in (a) of FIG. 3C, the screw portion 122 of the overall adjustment mechanism 120 is turned to rotate the housing 27 around the support shaft 28. By this rotation, the housing 27 tilts and changes its posture. Then, as shown in FIG. 3C (b), the lengths and positions of the scanning lines SK, SC, SM, and SY are adjusted. Specifically, when the inclination of the housing 27 is an angle α (see (a) in FIG. 3C), the lengths of the scanning lines SK, SC, SM, and SY are substantially equal to the separation distance between the two virtual reference lines B. The end positions of the scanning lines SK, SC, SM, and SY are on or near the virtual reference line B. After adjusting the attachment angle and the like in this way, the laser exposure device 20 is attached and fixed to the image forming apparatus 1. In other words, when the laser exposure device 20 is attached to the main body of the image forming apparatus 1, the posture of the laser exposure device 20 is adjusted to adjust the magnification of the scanning lines SK, SC, SM, and SY.
In addition, since the magnification adjustment is performed by rotating the laser exposure device 20 in this way, a shift in the sub-scanning direction occurs, but this can be dealt with by performing an electrical correction.

  Here, FIG. 4 is a diagram showing a modification of the present embodiment. That is, the configuration shown in FIG. 4 can be adopted instead of the configuration shown in FIG. More specifically, in the configuration shown in FIG. 4, the support shaft 28 is disposed at the lower portion of the housing 27, and the overall adjustment mechanism 120 is disposed at the upper portion of the housing 27. Since the individual adjustment and the overall adjustment in this case are the same as the procedure already described, the description thereof is omitted. In this case, the Y color closest to the support shaft 28 is the reference color.

  FIG. 5 is a diagram showing another modification of the present embodiment. Instead of the overall adjustment mechanism 120 shown in FIG. 3B (a), an overall adjustment mechanism 130 shown in FIG. 5 may be employed. More specifically, the overall adjustment mechanism 130 shown in FIG. 5 includes a support shaft 28, a receiving portion (not shown) that receives the support shaft 28 on the main body side of the image forming apparatus 1 that receives the support shaft 28, and a bottom portion of the housing 27. And a moving plate 132 having a hole 132a for receiving the protruding portion 131. The moving plate 132 is attached to the main body side of the image forming apparatus 1 so as to be movable in the direction of the arrow X. Since the protrusion 131 is inserted into the hole 132 a of the moving plate 132, the housing 27 rotates around the support shaft 28 as the moving plate 132 moves. As described above, the overall adjustment mechanism 130 rotates the housing 27 by the movement of the moving plate 132 attached to the main body side of the image forming apparatus 1. The overall adjustment mechanism 120 shown in FIG. 3B (a) rotates the housing 27 by the rotation of the housing 27, that is, the screw portion 122 on the laser exposure device 20 side. In this case, the color K closest to the support shaft 28 is set as the reference color.

[Second Embodiment]
6A, 6B, and 6C are diagrams for explaining the laser exposure device 20 applied to the image forming apparatus 1 according to the second embodiment. 6A to 6C are side views showing the positional relationship between the laser exposure device 20 and the three photosensitive drums 11, and FIG. 6B is a side view showing the three photosensitive drums 11. It is the front view seen from 20 side.
The laser exposure device 20 shown in FIGS. 6A to 6C irradiates each of the photosensitive drums 11 with three laser beams LC, LM, and LY. That is, in the first embodiment, the four laser beams LK, LC, LM, and LY are irradiated from the laser exposure unit 20, but in the present embodiment, the three laser beams LC, LM, and LY are irradiated. Is irradiated from the laser exposure device 20, and the laser beam LK is not irradiated.
More specifically, the support shaft 28 in the laser exposure device 20 of the present embodiment is disposed in the vicinity of the position where the laser beam LM located at the center of the three laser beams LC, LM, LY is emitted. . For this reason, the shift | offset | difference of the subscanning direction accompanying rotation in the case of whole adjustment is suppressed. The rotation center of the support shaft 28 is from the center position of the line connecting the emission position of the laser beam LM and the emission position of the adjacent laser beam LC to the emission position of the laser beam LY adjacent to the emission position of the laser beam LM. It is preferable to arrange in the section to the center position of the line connecting the two. In this case, the M color closest to the support shaft 28 is set as the reference color.

  The laser exposure device 20 according to the present embodiment includes an individual adjustment mechanism 110M for adjusting only the scanning line SM and an overall adjustment mechanism 120 for adjusting the attitude of the housing 27 as a configuration necessary for magnification adjustment. ing. That is, the individual adjustment mechanism 110M is attached to the M-color scanning line SM that is the reference color. Note that the individual adjustment mechanism 110M may have the same configuration as the individual adjustment mechanism 110M shown in FIG. Further, instead of the overall adjustment mechanism 120, an overall adjustment mechanism 130 shown in FIG. 5 can be used.

  If the positions of the scanning lines SK, SC, SM, and SY with respect to the virtual reference line B vary as shown in FIG. 6A (b), the individual adjustment mechanism 110M is used as shown in FIG. 6B (b). In addition, the length and position of the scanning line SM are adjusted so that the scanning line SM is positioned in a trapezoidal region formed by connecting the ends of the scanning line SC and the scanning line SY that are parallel to each other. After that, as shown in FIG. 6C (a), the screw portion 122 of the overall adjustment mechanism 120 is turned to rotate the housing 27 around the support shaft 28. Then, as shown in FIG. 6C (b), the lengths of the scanning lines SC, SM, SY are substantially the same as the distance between the two virtual reference lines B, and the end of the scanning lines SC, SM, SY The position is adjusted so as to be on or near the virtual reference line B. After adjusting the magnification in this way, the laser exposure device 20 is attached and fixed to the image forming apparatus 1.

  Here, FIG. 7 is a diagram illustrating a modification of the present embodiment. That is, in the configuration shown in FIG. 7, the position of the individual adjustment mechanism 110M and the position of the support shaft 28 are different from each other. That is, the individual adjustment mechanism 110M is disposed at an intermediate position in the vertical direction, specifically, at the position of the housing 27 from which the laser beam LM is emitted, while the support shaft 28 is disposed at the upper end portion of the housing 27. It is installed. For this reason, the separation distance between the screw portion 122 of the individual adjustment mechanism 110M and the support shaft 28 is increased, and the accuracy of adjustment by the feed screw action is increased. As another modification, a configuration in which the support shaft 28 is disposed at the lower end of the housing 27 is also conceivable. In this case, the C color closest to the support shaft 28 is the reference color.

[Third Embodiment]
8A and 8B are diagrams for explaining a laser exposure device 20 applied to the image forming apparatus 1 according to the third embodiment. 8A to 8B are side views showing the positional relationship between the laser exposure device 20 and the three photosensitive drums 11, and FIG. 8B is a side view showing the three photosensitive drums 11 as a laser exposure device. It is the front view seen from 20 side.
Since the basic configuration of the laser exposure device 20 shown in FIGS. 8A to 8B is the same as that of the second embodiment, description thereof is omitted. More specifically, in the laser exposure device 20 of the present embodiment, the arrangement of the emitted laser beams LC, LM, and LY is different from that of the second embodiment. Specifically, the laser beam LM, the laser beam LY, and the laser beam LC are arranged in this order from the lower side to the upper side. That is, the laser beams LM and LC are disposed at both ends, and the laser beam LY is disposed between the laser beams LM and LC. In this case, the Y color closest to the support shaft 28 is the reference color.

  Further, the laser exposure device 20 of the present embodiment differs from the second embodiment in the configuration necessary for magnification adjustment. Specifically, the laser exposure device 20 of the present embodiment does not include the individual adjustment mechanism 110.

  The magnification adjustment in the present embodiment performs only the overall adjustment using the overall adjustment mechanism 120. That is, overall adjustment is performed without performing individual adjustment. This will be described. The most inconspicuous yellow (Y) among yellow (Y), magenta (M), and cyan (C) is used as the center color, and scanning formed on the photosensitive drum 11 by the laser beam LY. Even if the length and position of the line SY are different from those of the other scanning lines SM and SC formed on the photosensitive drum 11 by the laser beams LM and LC, they are not conspicuous. Therefore, in the case of such a scanning line arrangement, the individual adjustment mechanism 110 can be omitted.

  Specifically, as shown in (b) of FIG. 8A, if there is variation in the position of the scanning lines SC, SY, SM with respect to the virtual reference line B, as shown in (a) of FIG. The screw part 122 of the mechanism 120 is rotated to rotate the housing 27 around the support shaft 28. Then, as shown in FIG. 8B (b), the lengths of the scanning lines SC and SM are substantially the same as the distance between the two virtual reference lines B, and the positions of the ends of the scanning lines SC and SM are virtual. Adjust so that it is above or in the vicinity of the reference line B. Even if the length and position of the scanning line SY are different from those of the other scanning lines SC and SM, it is considered that there is no problem in image quality. After adjusting the magnification in this way, the laser exposure device 20 is attached and fixed to the image forming apparatus 1.

[Fourth Embodiment]
FIG. 9 is a view for explaining a laser exposure device 20 applied to the image forming apparatus 1 according to the fourth embodiment. FIG. 9A shows the laser exposure device 20, the five photosensitive drums 11, and FIG. FIG. 5B is a front view of the five photosensitive drums 11 as viewed from the laser exposure unit 20 side.
The laser exposure unit 20 shown in FIG. 9A irradiates each of the photosensitive drums 11 with five laser beams LK, LC, LM, LY, and LS. The laser beam LS here represents a toner image of a special color (special color) such as a corporate color (for example, yellow of company A, green of company B, etc.), foaming toner for braille, fluorescent color, toner for improving glossiness, and the like. It is for forming.
In the laser exposure device 20 of the present embodiment, the support shaft 28 is disposed at the upper end portion of the housing 27.

  In addition, the laser exposure device 20 of the present embodiment has a configuration necessary for magnification adjustment, an individual adjustment mechanism 110C for adjusting only the scanning line SC, and an individual adjustment mechanism 110M for adjusting only the scanning line SM. And an individual adjustment mechanism 110Y for adjusting only the scanning line SY and an overall adjustment mechanism 120 for adjusting the attitude of the housing 27. The individual adjustment mechanisms 110C, 110M, and 110Y may have the same configuration as the individual adjustment mechanism 110M shown in FIG. Further, instead of the overall adjustment mechanism 120, an overall adjustment mechanism 130 shown in FIG. 5 can be used. In this case, the color K closest to the support shaft 28 is set as the reference color.

  As shown in FIG. 9B, if there are variations in the positions of the scanning lines SK, SC, SM, SY, SS with respect to the virtual reference line B, the individual adjustment mechanisms 110C, 110M, 110Y are used in parallel. The lengths and positions of the scanning lines SC, SM, SY are set so that the scanning lines SC, SM, SY are located in a trapezoidal region formed by connecting the ends of the scanning lines SK and SS. adjust. Thereafter, the screw portion 122 of the overall adjustment mechanism 120 shown in FIG. 9A is rotated to rotate the housing 27 around the support shaft 28, and the lengths of the scanning lines SC, SM, SY are two virtual reference lines. It is substantially the same as the separation distance of B, and is adjusted so that the positions of the ends of the scanning lines SC, SM, SY are above or near the virtual reference line B. After adjusting the magnification in this way, the laser exposure device 20 is attached and fixed to the image forming apparatus 1.

  Here, FIG. 10 is a diagram showing a modification of the present embodiment. That is, in the configuration shown in FIG. 10, the support shaft 28 is disposed in the vicinity of the emission position of the laser beam LM located at the center among the five laser beams LK, LC, LM, LY, and LS. That is, the support shaft 28 is located at the approximate center in the vertical direction. Also, individual adjustment mechanisms 110K, 110C, 110Y, and 110S and an overall adjustment mechanism 120 are provided. Even with such a configuration, the magnification can be adjusted as in the case shown in FIG. In this case, the M color closest to the support shaft 28 is the reference color. In addition, as another modification, a configuration in which the support shaft 28 is disposed at the lower end portion of the housing 27 is also conceivable.

1 is a diagram illustrating an example of a configuration of an image forming apparatus according to a first embodiment. It is a side view explaining schematic structure of the laser exposure device of this Embodiment. (A) is a side view showing the positional relationship between the laser exposure device and the four photosensitive drums, and (b) is a front view of the four photosensitive drums as viewed from the laser exposure device side. (A) is a side view showing the positional relationship between the laser exposure device and the four photosensitive drums, and (b) is a front view of the four photosensitive drums as viewed from the laser exposure device side. (A) is a side view showing the positional relationship between the laser exposure device and the four photosensitive drums, and (b) is a front view of the four photosensitive drums as viewed from the laser exposure device side. It is a figure which shows one modification of this Embodiment. It is a figure which shows the other modification of this Embodiment. It is a figure for demonstrating the laser exposure device applied to the image forming apparatus which concerns on 2nd Embodiment, (a) is a side view which shows the positional relationship of a laser exposure device and three photoreceptor drums. (B) is a front view of the three photosensitive drums as viewed from the laser exposure device side. (A) is a side view showing a positional relationship between a laser exposure device and three photosensitive drums, and (b) is a front view of the three photosensitive drums as viewed from the laser exposure device side. (A) is a side view showing a positional relationship between a laser exposure device and three photosensitive drums, and (b) is a front view of the three photosensitive drums as viewed from the laser exposure device side. It is a figure which shows one modification of this Embodiment. It is a figure for demonstrating the laser exposure device applied to the image forming apparatus which concerns on 3rd Embodiment, (a) is a side view which shows the positional relationship of a laser exposure device and three photoreceptor drums. (B) is a front view of the three photosensitive drums as viewed from the laser exposure device side. (A) is a side view showing a positional relationship between a laser exposure device and three photosensitive drums, and (b) is a front view of the three photosensitive drums as viewed from the laser exposure device side. It is a figure for demonstrating the laser exposure device applied to the image forming apparatus which concerns on 4th Embodiment, (a) is a side view which shows the positional relationship of a laser exposure device and five photosensitive drums. (B) is a front view of the five photosensitive drums as viewed from the laser exposure device side. It is a figure which shows one modification of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 11 ... Photosensitive drum, 20 ... Laser exposure device, 27 ... Housing, 28 ... Support shaft, 110K, 110C, 110M, 110Y, 110S ... Individual adjustment mechanism, 120, 130 ... Whole adjustment mechanism, B ... Virtual reference line, LK, LC, LM, LY, LS ... Laser light, SK, SC, SM, SY, SS ... Scan line, α ... Angle

Claims (8)

A plurality of image carriers;
An exposure apparatus that scans and exposes the plurality of image carriers by emitting a plurality of light beams corresponding to the plurality of image carriers;
A holding member that includes a rotating shaft and holds the exposure apparatus;
First adjusting means for adjusting one of the plurality of light beams emitted from the exposure apparatus;
Second adjusting means for adjusting a plurality of light beams by rotating the holding member around the rotation axis of the holding member;
An image forming apparatus including:   The image forming apparatus according to claim 1, wherein the number of the first adjusting units is smaller than the number of the plurality of light beams emitted from the exposure apparatus. The exposure apparatus emits three light beams,
3. The image forming apparatus according to claim 2, wherein one of the three light beams emitted from the exposure apparatus is adjusted by the first adjustment unit. 4. The exposure apparatus emits four light beams,
3. The image forming apparatus according to claim 2, wherein two light beams excluding light beams at both ends of the four light beams emitted from the exposure apparatus are adjusted by the first adjustment unit. The exposure apparatus emits five light beams,
The rotating shaft of the holding member is located in the vicinity of the light beam at one end of the five light beams emitted from the exposure apparatus,
3. The image forming apparatus according to claim 2, wherein three light beams excluding the light beams at both ends of the five light beams emitted from the exposure apparatus are adjusted by the first adjusting unit. The exposure apparatus emits five light beams,
The rotation shaft of the holding member is positioned in the vicinity of one central light beam among the five light beams emitted from the exposure apparatus,
3. The image forming apparatus according to claim 2, wherein three light beams excluding the light beams at both ends of the five light beams emitted from the exposure apparatus are adjusted by the first adjusting unit. An optical scanning device that emits a plurality of light beams to be scanned and exposed on the object to be scanned;
A holding member that includes a rotating shaft and holds the optical scanning device corresponding to the plurality of scanned objects;
An apparatus main body to which the plurality of scanned objects are attached and the holding member is attached via the rotation shaft of the holding member;
Adjusting means for adjusting the optical scanning device with respect to the plurality of scanned objects by rotating the holding member around the rotation axis of the holding member;
An image forming apparatus including: The optical scanning device emits three light beams including Y color,
The image forming apparatus according to claim 7, wherein the light beam of Y color among the three light beams is positioned between the other two light beams.

Images