JP5504986B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus, and more particularly to adjustment of scanning lines of an optical scanning device.

  In recent years, image forming apparatuses such as copiers, printers, and facsimiles using an electrophotographic process have been reduced in size and price, and at the same time, higher speed and higher image quality are required. . In color image forming apparatuses, a tandem type that can cope with high speed is widely adopted. In order to reduce the size of the tandem type image forming apparatus, the pitch (interval) of a plurality of photoconductors is provided. ) Tend to be narrower.

  The optical scanning device for forming the electrostatic latent image on the photosensitive member is not limited to one image forming device, and there is a configuration in which each photosensitive member is provided with an optical scanning device individually. In such a configuration, it is possible to reduce the size of the optical scanning device, but since the polygon scanner is expensive, mounting a plurality of optical scanning devices increases the cost. On the other hand, when there is one (one) optical scanning device, only one polygon scanner is required. However, the optical path to the photosensitive member becomes complicated, and the provision of the folding mirror leads to an increase in the size of the optical scanning device. Recently, an image forming apparatus that includes two optical scanning devices, reduces the number of polygon scanners, and avoids the complexity of the optical path, and has been released.

  In recent years, in order to reduce the size of the apparatus, many so-called in-body discharge type image forming apparatuses in which a discharge section is provided in the apparatus casing have been produced. Regarding the in-body discharge type, for example, in Japanese Patent Application Laid-Open No. 2004-271896 (Patent Document 1), Japanese Patent Application Laid-Open No. 11-160941 (Patent Document 2), Japanese Patent Application Laid-Open No. 8-339106 (Patent Document 3), and the like. Disclosure has been made.

  By the way, with regard to image quality, a decrease in image quality due to color misalignment or the like is a major problem in color image forming apparatuses. This is because the latent images written on the respective photoconductors are misaligned, misaligned during the transfer process, or misaligned during fixing. In order to improve the image quality of an image, a method of reducing color misalignment when scanning lines are overlapped by deforming or moving a folding mirror or a scanning lens is widely known. For example, the center of the back surface of the reflecting surface of the folding mirror is bent with a screw to correct the bending of the scanning line, or the lens is deformed by pressing with a screw from the sub-scanning direction of the lens, and the scanning line is bent. The method is used.

  Also, a method is known in which when the scanning lines are written with an inclination with respect to the photosensitive member, the mirror and the lens end are moved back and forth in the optical axis direction so that the positions of the scanning lines coincide with each other.

  Regarding the degradation of image quality, it is fully conceivable that the color deviation due to the inclination of the scanning line and the registration deviation in the sub-scanning direction occurs not only at the time of assembly adjustment at the factory but also upon arrival at the user. For example, when the optical scanning device of the image forming apparatus is assembled or when the optical scanning device has insufficient rigidity, a scanning line is easily set when there is a step in the user's machine installation. Inclination from the position and misalignment in the sub-scanning direction frequently occur. On the other hand, the scanning line curve hardly fluctuates.

  Conventionally, methods have been proposed for adjusting the inclination and bending of the scanning line using a motor or the like, but a large color shift occurs only when the machine is moved. It is wasteful to spend the cost on the mechanism.

  Even when the adjustment is performed manually, if the adjustment mechanism is performed with the front cover open, it is troublesome to open and close the cover one by one, and adjustment takes time. If work is to be performed with the cover open, a jig is required so that the machine can operate even when the cover is open. In addition, it takes time because it cannot be adjusted while viewing the discharged image.

  Furthermore, if an attempt is made to adjust by putting a hand from the in-body discharge section, it takes time to access the adjustment portion, and the worst scanner portion must be removed for work. Further, since there is a possibility of contact with the discharged paper, the tool or the like must be temporarily retracted, which is cumbersome and takes time to adjust.

  The present invention solves the above-mentioned problems in the conventional image forming apparatus, and can easily perform adjustment in a state where it is easy to work in the case where color deviation due to inclination of the scanning line or registration deviation in the sub-scanning direction occurs. An object of the present invention is to provide an image forming apparatus excellent in adjustment workability.

According to the present invention, there is provided an image forming apparatus including an optical scanning device that scans a surface to be scanned by deflecting a light beam emitted from a light source by a deflector, and the light beam on the surface to be scanned a scan line adjusting means for changing the position adjustment holes for adjusting the scanning line adjusting means on the exterior member of the image forming apparatus is provided, Ri adjustable der the scanning line adjusting means from outside the device, A paper discharge unit is provided on an upper surface of the image forming apparatus, the adjustment hole is disposed outside a paper discharge region overlapping with the recording medium discharged to the paper discharge unit, and the scanning line adjustment unit is configured to discharge the discharge line. The optical scanning device includes an upper lid, and an introduction hole is formed in the upper lid, and the adjustment hole and the introduction hole are: The adjustment arranged outside the discharge area. By adjusting tool to be inserted through the hole, it is solved by the image forming apparatus characterized by being arranged so as to be able adjust the scanning line adjusting means disposed within the projection range.

Further, it is preferable that the adjustment hole is provided at a position where the adjustment hole is visible from above the image forming apparatus.
Further, it is preferable that a reading device for reading a document image is provided, and the adjustment hole is disposed so as not to overlap a projection surface of the reading device.

Preferably, a paper discharge unit is provided between the reading device and the optical scanning device, and the adjustment hole is disposed so as not to overlap the recording medium discharged to the paper discharge unit .

Further , it is preferable that the adjustment hole is covered with a covering member.

It is preferable that a guide rib for guiding the insertion of the adjustment tool is provided around the adjustment hole.
Further, it is preferable that the scanning line adjusting means adjusts the inclination of the scanning line.

Further, it is preferable that the scanning line adjusting means adjusts the position of the scanning line in the sub-scanning direction.
Preferably, the scanning line adjusting means has an adjusting screw, and the adjusting screw is brought into contact with the member to be adjusted in a non-vertical direction or a non-horizontal direction in the optical axis direction.

Further, it is preferable that a plurality of image carriers as scanning surfaces by the optical scanning device are provided and a visible image formed on each image carrier can be output in an overlapping manner.
It is preferable that a plurality of the optical scanning devices are provided.

  According to the image forming apparatus of the present invention, since the adjustment hole is provided in the exterior member and the scanning line adjustment unit can be adjusted from the outside of the apparatus, the adjustment work can be easily performed in an easy-to-work state. Further, there is no need to open the front cover or remove the optical scanning device, and the adjustment work becomes extremely easy. Furthermore, since it is not necessary to open the front cover, the power is not turned off by the interlock switch, and the down time of the apparatus can be reduced. Further, since the adjustment work can be performed while the apparatus is operable, the adjustment result can be confirmed immediately.

According to the configuration of the second aspect, the adjustment hole can be easily viewed and accessed, and workability is improved.
With the configuration of the third aspect, the reading device does not interfere with the adjustment work, and the adjustment work is easy to perform.
With the configuration of the fourth aspect, the recording medium discharged to the in-body discharge unit does not interfere with the adjustment work, and the adjustment work is easy to perform.

According to the configuration of the fifth aspect , it is possible to prevent dust and the like from entering through the adjustment hole, and it is possible to prevent image quality deterioration and machine failure.
According to the configuration of the sixth aspect , the tool can be easily inserted into the adjustment hole, and workability can be improved.

With the configuration of the seventh aspect , it is possible to obtain a good output image by adjusting the inclination of the scanning line.
According to the configuration of the eighth aspect , it is possible to obtain a good output image by adjusting the position of the scanning line in the sub-scanning direction.

According to the configuration of the ninth aspect, the feed pitch can be made fine with respect to the feed direction of the adjustment screw, and the adjustment resolution can be increased. Therefore, finer color matching is possible. In addition, since the degree of freedom of the screw angle with respect to the optical element to be adjusted is large and can be set to an angle that can be easily adjusted, the adjustment means can be easily accessed, and the adjustment work is facilitated.

According to the configuration of the tenth aspect , it is possible to obtain a high-quality color image without color misregistration in an image forming apparatus having a plurality of image carriers.
With the configuration of the eleventh aspect , the optical path of the light beam can be simplified, and the optical scanning device and the image forming apparatus can be miniaturized.

1 is an external perspective view showing an in-body discharge type copying apparatus as an example of an image forming apparatus according to the present invention. It is a top view of the copying apparatus. FIG. 2 is a configuration diagram illustrating an outline of an image forming unit of the copying apparatus. FIG. 6 is a top view of a state where a paper discharge tray is removed. It is a top view of the state which removed the upper cover of one optical scanning device. It is a fragmentary sectional view which shows the positional relationship of an adjustment hole and an optical scanning device. FIG. 6 is a schematic diagram illustrating a configuration in which an adjustment screw is in a paper discharge area or a reading device projection range. FIG. 10 is a partial perspective view illustrating a configuration example in which an adjustment hole is provided in a member different from the paper discharge tray. It is a fragmentary perspective view which shows the structural example which provided the adjustment square hole which replaces an individual adjustment hole. It is a partial top view which shows the state which removed the cover member which covers the adjustment square hole. It is a schematic diagram which shows the general structure of an optical scanning device. It is a schematic diagram which shows an example of the adjustment method of a scanning line. It is a schematic diagram which shows the example in which the displacement of the mirror by two adjustment screws is special. 1 is an external perspective view illustrating an example of an image forming apparatus that does not have a reading unit. It is a top view of the color printer. It is sectional drawing which shows the internal structure. It is a perspective view which cuts out a part of apparatus and shows an internal structure. 2 is a cross-sectional view showing an internal configuration of a color printer including one optical scanning device. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view showing an in-body discharge type copying apparatus as an example of an image forming apparatus according to the present invention. FIG. 2 is a top view of the copying apparatus. In the copying apparatus of this embodiment shown in these drawings, an image forming unit 1 is provided so as to occupy the central portion of the apparatus main body, and a paper feeding unit 2 is provided below the image forming unit 1. A space in the housing above the image forming unit 1 is configured as an in-cylinder sheet discharge unit 5, and a bottom part of the in-cylinder sheet discharge unit 5 is a sheet discharge tray 6. Further, a reading unit 3 for reading a document image is disposed above the in-body discharge unit 5. A pressure plate 4 is disposed on the upper surface of the reading unit 3. Although not provided in this embodiment, an automatic document feeder called ADF may be mounted on the upper surface of the reading unit 3. An operation panel 7 is provided on the front side of the apparatus on one side of the reading unit 3. The operation panel 7 includes display means 8 for displaying various information. Note that the display unit 8 may be a touch panel that allows input.

  FIG. 3 is a configuration diagram illustrating an outline of the image forming unit 1. The image forming unit 1 of this example is configured to be capable of forming a full-color image by adopting a tandem method, and includes four image forming units 30 (Bk, M, C, and Y). The image forming units 30 (Y, C, M, Bk) are arranged side by side along the upper running side of the intermediate transfer belt 38. The intermediate transfer belt 38 wound around the support rollers 36 and 37 is driven to run counterclockwise in the drawing.

  Each image forming unit 30 has the same configuration except for the color of the toner to be handled, and includes a photosensitive drum 31 as an image carrier. Around the photosensitive drum 31, a charging unit 32, a developing device 33, a cleaning unit 34, and the like are arranged. Further, a transfer as a primary transfer unit is provided inside the intermediate transfer belt 38 so as to face each photosensitive drum 31. A roller 35 is provided.

  An optical scanning device 40 is provided above the four image forming units 30. The optical scanning device 40 has optical elements such as a polygon mirror, a lens, and a mirror, and irradiates the surface of the photosensitive drum 31 of each color image forming unit with light-modulated laser light. In the illustrated example, the optical scanning device is provided for each image forming unit. However, a configuration in which four photoconductors are scanned by one optical scanning device, or four photoconductors are scanned by two optical scanning devices. It is also possible to configure.

  A paper feed tray 21 for stacking paper is disposed in the paper feed unit 2 (FIG. 1) located at the lower part of the apparatus main body, and the paper feed roller separates and feeds the paper one by one. A registration roller 22 is provided above the paper feed roller (downstream in the paper transport direction). Further, a transfer roller 23 as a secondary transfer unit is provided above the registration roller 22 so as to be opposed to a support roller 37 serving as a transfer counter roller, thereby forming a secondary transfer portion.

  A fixing device 24 is provided above the secondary transfer portion. The fixing device 24 of the present example has a fixing roller and a pressure roller, and fixes the sheet on which the unfixed toner image is transferred at the secondary transfer unit by heating and pressing. A paper discharge roller 25 is provided above the fixing device 24 and discharges the fixed paper onto the paper discharge tray 6 of the in-body paper discharge unit.

  Since the image forming operation in the image forming unit 1 configured as described above is based on a conventionally known electrophotographic method, the description of the image forming operation is omitted. In the present embodiment, setting of the number of copies, paper selection, designation / input of image density, copy magnification, and the like can be performed while viewing the display on the display unit 8 from the operation panel 7 shown in FIG.

  As described above, in the image forming unit 1, the optical scanning device 40 is provided on the tandem image forming unit in which the four image forming units 30 (Bk, M, C, Y) are arranged. As can be seen from FIG. 3, the optical scanning device 40 is disposed at a position immediately below the paper discharge tray 6 which is the bottom surface of the in-body paper discharge unit. As shown in FIGS. 1 and 2, in the present embodiment, four adjustment holes 10 are provided in the front end portion (end portion on the front side of the apparatus) of the paper discharge tray 6. The adjustment hole 10 is for accessing the optical scanning device 40 located immediately below the paper discharge tray 6 to adjust the scanning line. A scanning line adjustment method will be described later. As can be seen from the top view of FIG. 2, the four adjustment holes 10 are provided at positions that do not overlap the reading unit 3 and the pressure plate 4 (outside the projection range). Further, as will be described later with reference to FIG. 4, the four adjustment holes 10 are provided at positions that do not overlap the paper discharged onto the paper discharge tray 6 of the in-body paper discharge unit 5. The size of the adjustment hole 10 is set to a size that can accommodate an adjustment tool such as a screwdriver or a hexagonal hole set key. What is necessary is just to set the shape of a hole suitably. In addition, it may be closed with a sealing member, a cover, or the like so that dust such as dust does not enter from the adjustment hole 10, or may be closed with a hole closing member such as a resin hook.

  In this example, the front end portion (end portion on the front side of the apparatus) of the paper discharge tray 6 is a part of the apparatus exterior material, and the adjustment hole 10 is provided in that part. It may be provided so as to be covered with another exterior material, and the adjustment hole 10 may be provided in the exterior member.

  FIG. 4 is a top view of the state in which the paper discharge tray 6 is removed. Here, a configuration is shown in which four photoconductors are scanned by two optical scanning devices (40, 40). By removing the paper discharge tray 6, the optical scanning devices 40 and 40 (part of them) arranged at the uppermost part of the image forming unit 1 can be seen. As shown in the figure, the upper lid of the optical scanning device 40 is provided with introduction holes 41 and 41 for introducing the tool inserted from the adjustment hole 10 into the optical scanning device. In the configuration including an optical scanning device for each image forming unit in FIG. 3, one introduction hole 41 is required for one optical scanning device 40. Although not shown, in a configuration in which four photoconductors are scanned by one optical scanning device, four introduction holes 41 are provided in the optical scanning device.

  FIG. 5 is a top view of a state in which the upper lid of one optical scanning device 40 is removed. FIG. 6 is a partial cross-sectional view showing the positional relationship between the adjustment hole 10 and the optical scanning device 40. As shown in these drawings, a polygon scanner 54 including a polygon mirror, which is a rotary polygon mirror as a light beam deflecting unit, a folding mirror 56, and the like are arranged inside the optical scanning device 40. Here, the configuration of the optical scanning device 40 is shown in a simplified manner and has a configuration as described later with reference to FIG. The folding mirror 56 is held by a holder 44, and the holder 44 is provided with an adjusting screw 45 for adjusting the scanning line. The adjustment screw 45 is provided so as to be positioned at an end portion on the front side of the image forming apparatus in the front-rear direction of the image forming apparatus so as to take a positional relationship of pushing the vicinity of one end portion in the longitudinal direction of the folding mirror 56. Since either tilt adjustment or registration adjustment is different depending on the machine, when adjusting both with a single mirror / optical element, bring the one that requires more adjustment to the front of the device. And the adjustment is made from the adjustment hole 10. In the following description, the optical element for adjusting the scanning line is described as a folding mirror, but it may be a lens or other optical element.

  The introduction hole 41 provided in the upper lid of the optical scanning device 40 is provided in accordance with the position of the adjustment screw 45. And the adjustment hole 10 mentioned above is provided so that the position of the introduction hole 41 may be met. The introduction hole 41 and the adjustment hole 10 are provided at positions corresponding to the adjustment screw 45 not only in the apparatus width direction but also in the apparatus front-rear direction. The scanning line may be adjusted with any mirror when a plurality of folding mirrors are provided, but it is desirable to adjust with the folding mirror closest to the photoconductor 31 on the optical path. In addition, the tilt adjustment and the registration adjustment may be combined into one mirror, or the tilt adjustment and the registration adjustment may be performed with different mirrors, respectively. In that case, the introduction hole 41 and the adjustment hole 10 are provided according to the mirror (adjustment screw) to be adjusted.

  Then, as shown in FIG. 6, the adjustment tool 49 is inserted from the adjustment hole 10, the tool 49 is introduced into the optical scanning device 40 from the introduction hole 41, and the adjustment screw 45 is turned to adjust the inclination or the registration. At this time, as is apparent from FIGS. 2 and 4, the adjustment hole 10 is provided at a position that does not overlap the reading unit 3 and the pressure plate 4. Further, the adjustment hole 10 is provided at a position where it does not overlap the paper discharged onto the paper discharge tray 6 of the in-body paper discharge unit 5. Therefore, when the adjustment tool 49 is inserted from the adjustment hole 10 to adjust the scanning line, the operation can be easily performed from above (upper surface) of the image forming apparatus.

  As shown in FIG. 6, the adjustment hole 10 includes a cylindrical guide rib 11 provided so as to surround the hole and extending toward the optical scanning device 40. The guide rib 11 is provided so as to project from an extended portion (portion on the front side of the apparatus) of the paper discharge tray 6 in which the adjustment hole 10 is provided or a cover or the like that is a separate member from the tray. The guide rib 11 guides the tool when the adjustment tool 49 is inserted and guides the tool into the lower introduction hole 41, and the tool 49 is easily introduced into the optical scanning device 40. If a guide rib similar to the guide rib 11 is provided in the introduction hole 41 (also on the upper lid of the optical scanning device 40), the tool can be guided to the adjustment screw 45 more easily. The guide rib 11 (and the guide rib provided in the introduction hole 41) is provided so that the size of the hole (hole) of the adjustment hole 10 (and the introduction hole 41) is smaller in the outlet portion than in the inlet portion. The play of the tool can be reduced, and the tool can be guided to the adjusting screw 45 more reliably.

  Here, in FIG. 6, the adjustment tool 49 is described so as to be perpendicular to the optical scanning device 40 (the angle β is 90 degrees), but the adjustment hole 10, the introduction hole 41, and the adjustment screw 45 are aligned. As long as they are aligned with each other, and β need not be 90 degrees. Further, the contact angle θ between the folding mirror 56 and the adjusting screw 45 is not necessarily perpendicular to the reflecting surface of the folding mirror 56 (θ = 90 degrees), and may be set in a direction that can be easily adjusted from above the machine. .

  Further, as will be described with reference to FIG. 7, the adjustment tool may be inserted while being tilted toward the back of the apparatus to adjust the scanning line. In FIG. 7, the right side of the figure is the front side of the apparatus, and the left side of the figure is the back side of the apparatus. In this example, the adjustment hole 10 and the introduction hole 41 are arranged so as to be shifted in the front-rear direction of the apparatus, and the adjustment hole 10 is closer to the front side than the introduction hole 41. Then, the adjustment tool 49 is inserted while being inclined toward the back of the apparatus, and the adjustment screw 45 is turned to adjust the scanning line of the folding mirror 56. “H” in the drawing indicates a paper discharge area or an area (projection range) that overlaps with the reading device 3, and the adjustment screw 45 is in the paper discharge area or the reading device projection range. The angle γ of the adjustment screw 45 with respect to the folding mirror 56 and the positions of the adjustment hole 10 and the introduction hole 41 are set as appropriate so that they can be performed from outside or outside the projection range of the reading device.

  Incidentally, an ordinary image forming apparatus is provided with an interlock switch that turns off the main power supply of the apparatus by opening the exterior cover during maintenance work or the like. Such an interlock switch is provided for the purpose of ensuring the safety of the user. Also in this embodiment, the main power supply of the apparatus is turned off by opening the front cover 9 shown in FIG. In the conventional image forming apparatus, it is necessary to open or remove an exterior cover such as a front cover to adjust the scanning line, and thus it takes time to open and close the cover and remove the cover, which is troublesome. Further, since the main power supply of the apparatus is turned off by opening or removing the outer cover, the result of the scanning line adjustment cannot be seen immediately (the output for seeing the adjustment result cannot be performed immediately).

  In contrast, in the present embodiment, the adjustment can be made from the adjustment hole 10 on the upper surface of the apparatus without opening the front cover 9, and the reading unit 3 does not get in the way as described above, and the adjustment work is very easy. is there. Furthermore, since the front cover 9 does not need to be opened, the main power supply of the apparatus is not turned off by the interlock switch, and it is possible to confirm the degree of adjustment by performing print output immediately after adjustment. It can be greatly improved. If adjustment is necessary after adjustment (after confirming the result), adjustment can be performed again immediately.

  FIG. 8 is a partial perspective view showing a configuration example (second embodiment) in which the adjustment hole 10 is not provided in a member constituting the paper discharge tray 6 but is provided in a separate member. In this figure, the apparatus exterior member 12 at the front side portion of the in-body sheet discharge section 5 is formed of a member different from the sheet discharge tray 6. An adjustment hole 10 is provided in the device exterior member 12. Other than this, the second embodiment is the same as the first embodiment described above, and a duplicate description is omitted.

Next, an embodiment (third embodiment) in which the scanning line can be adjusted from the upper surface of the apparatus without providing the individual adjustment holes 10 will be described.
FIG. 9 is a partial perspective view showing (a part of) the image forming apparatus of the third embodiment. As shown in this figure, in the apparatus of the present embodiment, the individual adjustment hole 10 is not provided in the exterior part of the front surface of the apparatus on the front side of the in-cylinder sheet discharge part 5, but instead the apparatus exterior part (discharge tray) 6 may be a member integral with 6 or a separate member). When the small cover 13 is removed, as shown in FIG. 10, the lower optical scanning devices 40 and 40 can be seen through the adjustment square hole 14, and an introduction hole 41 provided in the upper lid of the optical scanning device can be accessed. . Then, the adjustment tool 49 described above is inserted from the introduction hole 41, and the adjustment screw 45 is turned in the same manner as in the first embodiment to adjust the scanning line of the folding mirror 56. Although an example in which two optical scanning devices 40 are provided is shown here, a configuration in which one or four optical scanning devices are provided is also possible. Since it is the same as that of the above-mentioned 1st, 2nd Example except having provided the adjustment square hole 14 (and the small cover 13 which block | closes it) instead of the individual adjustment hole 10, duplication description is abbreviate | omitted.

Next, a scanning line adjustment method in the optical scanning device will be described. Note that the scan line adjustment itself can be performed using a conventionally known method, and thus will be described using a general configuration.
FIG. 11 is a schematic diagram illustrating a general configuration of the optical scanning device. Normally, the optical scanning device includes a laser diode 51 as a light source unit, a collimator lens 52 that converts laser light diffused from the light source unit into parallel light, and a cylindrical lens 53 that focuses the parallel light with a rotating polygonal mirror 54 as a deflector. The laser beam scanned by the rotating polygon mirror 54 and diffused again is focused on the photosensitive drum 31 which is the medium to be scanned, and the fθ lens 55 for making the scanning speed constant, and the scanned laser beam is the photosensitive member. The mirror 56 is guided onto the drum 31. Since the present invention is characterized in that the scanning line is adjusted, in the embodiment, the mirror 56 is configured so that the scanning line can be adjusted as described with reference to FIG. However, the scanning line may be adjusted using an optical element other than the mirror, for example, a lens.

  When scanning with a laser beam, a scanning line Li deviating in parallel with a desired scanning line L on the photosensitive drum 31 and a scanning line Lk deviating from an angle called “angular deviation”. It becomes. Causes of the deviation include processing errors and assembly errors of each component and housing, and it takes a lot of labor to eliminate them, and it is almost impossible in cost with the current processing technology.

  That is, when writing on a sheet on which a format has been printed in advance, there is a disadvantage that the format deviates from the format. Therefore, adjustment work for correcting the shift of the scanning line must be performed. Therefore, by adjusting the scanning line using the mirror 56, it is necessary to bring the shifted scanning line Li or scanning line Lk closer to the desired scanning line L.

FIG. 12 is a schematic diagram illustrating an example of a scanning line adjustment method.
FIG. 2A shows a plan view of the folding mirror 56. FIG. Each of FIGS. (B) and (c) is a sectional view showing how the folding mirror 56 is held by the holder 44. The holder 44 that holds the folding mirror 56 is formed of aluminum casting, plastic, or the like, and is provided with a screw hole into which the adjustment screw 45 (45A, 45B) is screwed. Further, the holder 44 has a convex portion 44a for placing the mirror on the adjustment screw 45A side in the mirror longitudinal direction, a convex portion 44b for placing the mirror on the adjustment screw 45B side in the mirror longitudinal direction, and an adjustment screw 45B side in the mirror longitudinal direction. On the opposite side, a convex portion 44c that protrudes from the holder wall portion is provided.

  FIG. 5B is a cross-sectional view taken along a plane perpendicular to the mirror passing through the point 60 of the return mirror 56. The folding mirror 56 is pressed from one side by a plate spring 67 fixed to the holder, and the opposite side is pressed by an adjusting screw 45A. The adjustment screw 45A is brought into contact with a point 60 in FIG. In FIG. 7B, the point where the adjusting screw 45A abuts on the mirror 56 is indicated by 76. A point where the mirror 56 abuts on the convex portion 44a is indicated by 68.

  FIG. 6C is a cross-sectional view taken along a plane perpendicular to the mirror passing through the straight line 63. The folding mirror 56 is pressed from one side by a leaf spring 74 fixed to the holder, and the opposite side is pressed by an adjustment screw 45B. The adjustment screw 45B is brought into contact with the mirror 56 at a point 64 on the straight line 63 in FIG. In FIG. 7B, the point where the adjusting screw 45B contacts the mirror 56 is indicated by 72. Further, the mirror 56 is in contact with a point 75 that is a corner of the convex portion 44c.

  That is, on one side of the folding mirror 56, one plane is defined by the three points 76, 72, and 75 described above, and the mirror reflecting surface is thereby fixed to one plane in the space. Further, for the purpose of restricting the movement of the mirror 56 on the plane, it abuts on the holder 44 (projections 44a and 44b) at points 68 and 73. Therefore, if the adjustment screw 45A and the adjustment screw 45B are advanced and retracted, the angle of the folding mirror 56 with respect to the scanning light beam can be changed within a certain range.

  That is, when the adjustment screw 45A is advanced and retracted, the mirror 56 rotates about the straight line 63, and the angle deviation (inclination) of the scanning line can be corrected. Further, when the adjustment screw 45B is advanced and retracted, the mirror 56 rotates about the straight line 61, and the positional deviation of the scanning line can be corrected. However, this positional deviation correction causes an angle deviation. However, if the straight line 61 is sufficiently large with respect to the straight line 63, the angle deviation will be small, and if the adjustment screw 45A is advanced and retracted again to correct the angle deviation, the scanning line is set to the desired scanning line L. Can do. As described above, the correction of the positional deviation includes the angular deviation, but the correction of the angular deviation includes almost no positional deviation, and thus the adjustment is easy.

  FIG. 13 shows a special case where the straight line 63 and the straight line 61 are orthogonal to each other. In this case, the positional deviation correction of the scanning line due to the advancement / retraction of the adjusting screw 45B includes almost no angular deviation, and the positional deviation correction and the angular deviation correction are independent of each other. Therefore, adjustment becomes easier.

  When using such an adjustment method, the adjustment tool 49 is inserted into the adjustment hole 10 or the adjustment square hole 14 described above, and the adjustment screw 45A or the adjustment screw 45B is turned to easily adjust the scanning line from above the image forming apparatus. It can be performed.

  It is fully conceivable that the color deviation due to the inclination of the scanning line and the registration deviation (positional deviation) in the sub-scanning direction occurs not only at the time of assembly adjustment at the factory but also when the user arrives. For example, when the optical scanning device of the image forming apparatus is assembled or when the optical scanning device has insufficient rigidity, a scanning line is easily set when there is a step in the user's machine installation. Inclination from the position or misalignment in the sub-scanning direction occurs. In such a case, with the image forming apparatus of the present invention, the adjustment operation can be performed in a state where it is easy to work from the upper surface of the apparatus without obstructing the reading unit or the ADF (if provided). Further, since the interlock is not turned off during adjustment, the work is not time-consuming, and the adjustment result can be confirmed immediately. Accordingly, it is possible to provide an image forming apparatus having excellent adjustment workability.

  Incidentally, the present invention is also applicable to an image forming apparatus that does not have a reading unit that reads a document image. An embodiment in which the present invention is applied to a printer which is an example of an image forming apparatus having no reading unit will be described with reference to FIGS. Note that the same reference numerals are used for the same or equivalent parts as those in the above-described in-body discharge type copying apparatus.

  FIG. 14 is an external perspective view showing a color printer as an example of an image forming apparatus according to the present invention. FIG. 15 is a top view of the color printer. FIG. 16 is a cross-sectional view showing the internal configuration. Further, FIG. 17 is a perspective view showing a part of the apparatus by cutting away so as to show the configuration of the image forming unit.

  In the color printer of this embodiment shown in these drawings, an image forming unit 1 is provided so as to occupy the central portion of the apparatus main body, and a paper feeding unit 2 is provided below the image forming unit 1. The upper surface of the apparatus above the image forming unit 1 is configured as a paper discharge unit 15, and the bottom of the paper discharge unit 15 is a paper discharge tray 6. Four adjustment holes 10 are provided on the front side (end portion on the front side of the apparatus) of the paper discharge tray 6. The adjustment hole 10 is for accessing the optical scanning device 40 located immediately below the paper discharge tray 6 to adjust the scanning line. The configuration of the image forming unit 1 shown in FIGS. 16 and 17 is the same as that of the image forming unit 1 of the above-described in-body discharge type copying apparatus. In addition, instead of the four adjustment holes 10, the adjustment square holes 14 may be provided, the member provided with the adjustment holes or the adjustment square holes may be a separate member from the paper discharge tray 6, and one optical scanning device is provided. Two or four may be used as in the case of the in-body discharge type copying apparatus described above.

  Also in the color printer of the present embodiment, the adjustment tool 49 is inserted from the adjustment hole 10 or the adjustment square hole 14 and the adjustment screw 45A or the adjustment screw 45B is turned, so that the scanning line of the optical scanning device can be easily formed from above the image forming apparatus. Adjustments can be made. Therefore, not only at the time of assembly adjustment at the factory, but also when the user arrives, it is possible to easily adjust the color misalignment due to the inclination of the scanning line and the registration misalignment (position misalignment) in the sub-scanning direction to obtain a high quality image. . Further, since the interlock is not turned off during adjustment, the work is not time-consuming, and the adjustment result can be confirmed immediately.

  FIG. 18 is a cross-sectional view of a color printer showing an example of a configuration including one optical scanning device in an embodiment of an image forming apparatus having no reading unit. The same parts as those in FIG. 3 are denoted by the same reference numerals, and description of the configuration is omitted. Also in this color printer, by providing the adjustment hole 10 or the adjustment square hole 14 in the exterior portion on the front side of the discharge tray on the upper surface of the apparatus, as in the above-described in-body discharge type copying apparatus and the color printer of FIG. The scanning line of the optical scanning device can be easily adjusted from above the device.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, an appropriate configuration can be adopted for each part of the optical scanning device, and as described above, the folding mirror or lens may be configured so that the scanning line can be adjusted. The shape and size of the adjustment hole can be arbitrarily set. The number of optical scanning devices is also arbitrary.

  The configuration of the image forming unit of the image forming apparatus is also arbitrary, and the arrangement order of the color process cartridges in the tandem type is arbitrary. Further, not only the intermediate transfer method but also a direct transfer method may be used. The present invention can also be applied to a full-color machine using three color toners, a full-color machine using four or more toners, a multi-color machine using two-color toners, or a monochrome apparatus. Of course, the image forming apparatus is not limited to a printer or a copying machine, but may be a facsimile machine or a multifunction machine having a plurality of functions.

DESCRIPTION OF SYMBOLS 1 Image formation part 2 Paper feed part 3 Reading part 4 Pressure plate 5 In-body paper discharge part 6 Paper discharge tray 10 Adjustment hole 11 Guide rib 13 Small cover 14 Adjustment square hole 30 Image forming unit 31 Photosensitive drum 40 Optical scanning device 41 Introduction hole 44 Holder 45 Adjustment screw 49 Adjustment tool 54 Polygon scanner 56 Folding mirror

JP 2004-271896 A Japanese Patent Laid-Open No. 11-160941 JP-A-8-339106

Claims (11)

An image forming apparatus including an optical scanning device that scans a surface to be scanned by deflecting a light beam emitted from a light source by a deflector,
Scanning line adjusting means for changing the position of the light beam on the surface to be scanned;
Adjusting hole for adjusting the scanning line adjusting means on the exterior member of the image forming apparatus is provided, Ri adjustable der the scanning line adjusting means from outside the device,
A paper discharge unit is provided on the upper surface of the image forming apparatus, and the adjustment hole is disposed outside a paper discharge region overlapping the recording medium discharged to the paper discharge unit,
The scanning line adjusting means is disposed within a projection range of the recording medium discharged to the paper discharge unit;
The optical scanning device includes an upper lid, and an introduction hole is formed in the upper lid.
The adjustment hole and the introduction hole are arranged so that the scanning line adjustment means arranged in the projection range can be adjusted by an adjustment tool inserted from the adjustment hole arranged outside the paper discharge area. the image forming apparatus characterized by being.   The image forming apparatus according to claim 1, wherein the adjustment hole is provided at a position that is visible from above the image forming apparatus. A reading device for reading a document image;
The image forming apparatus according to claim 1, wherein the adjustment hole is disposed so as not to overlap a projection surface of the reading device. A paper discharge unit is provided between the reading device and the optical scanning device,
The image forming apparatus according to claim 3, wherein the adjustment hole is disposed so as not to overlap a recording medium discharged to the paper discharge unit. Characterized in that said the adjusting hole is covered with the covering member, the image forming apparatus according to any one of claims 1-4. Wherein the periphery of the adjustment hole, wherein the guide rib for guiding the insertion of the adjustment tool is provided, the image forming apparatus according to any one of claims 1-5.   The image forming apparatus according to claim 1, wherein the scanning line adjusting unit adjusts an inclination of the scanning line.   The image forming apparatus according to claim 1, wherein the scanning line adjustment unit adjusts a position of the scanning line in the sub-scanning direction. The scanning line adjustment means has an adjustment screw, and the adjustment screw is brought into contact with the member to be adjusted in a non-vertical direction or a non-horizontal direction in the optical axis direction . the image forming apparatus according to any one of 8.   2. The image forming apparatus according to claim 1, wherein a plurality of image carriers as scanning surfaces by the optical scanning device are provided, and visible images formed on the image carriers can be output in an overlapping manner. apparatus. Characterized in that it comprises a plurality of the optical scanning device, an image forming apparatus according to any one of claims 1-10.

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