JP2003205649A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus in which assembling performance is enhanced and a scanner unit can be supported and secured at a low cost with high accuracy. <P>SOLUTION: The imaging apparatus comprises a supporting member 43 having a coil spring 42 secured to left and right side plates 32a and 32b and urging the protruding part 41 of a scanner unit toward abutting faces 38 and 39 provided in the left and right side plates 32a and 32b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a function of forming an image on a transfer material (recording medium) such as a sheet, such as a copying machine, a printer or a facsimile machine. is there.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, there is an in-line type multicolor image forming apparatus in which a plurality of photosensitive drums 201 are arranged in a line.

Such a multicolor image forming apparatus is roughly divided into a plurality of photosensitive drums 2 as shown in FIG.
FIG. 10 shows a horizontal arrangement 200A in which 01s are arranged in the horizontal direction.
As shown in (b), there is a vertical arrangement 200B in which a plurality of photosensitive drums 201 are vertically arranged.

[0004] The general horizontal arrangement has a feature that the height is low but the installation area is large. On the other hand, the vertically arranged structure 200B has a merit that the installation area can be reduced although the height is high.

Although the inline type multicolor image forming apparatus can increase the printing speed by arranging a plurality of photosensitive drums and scanner units, it requires a space for arranging the image forming system (photosensitive drums and scanner units). The whole becomes bigger. Further, since parts are also required for each photosensitive drum and scanner unit, the number of points increases.

[0006] In view of the above, how to reduce the size and cost to finish the product has become a major issue.

Further, from the viewpoint of image color shift, it is considered that the parallelism of each photosensitive drum 201 and the positional accuracy of the scanner unit 202 with respect to the drum are very important.

Conventionally, as shown in FIG. 8, the photosensitive drum 201 is positioned by abutting against the drum supporting blocks 204 which are accurately attached to the left and right side plates 203a and 203b.

Further, the scanner unit 202 has a scanner base 205 so as to bridge the left and right side plates 203a and 203b.
Was mounted, and the scanner unit 202 was accurately fixed on the scanner base 205 with screws to perform positioning.

[0010]

By the way, in the above-mentioned prior art, it has been necessary to reduce the number of parts without impairing the performance (positional accuracy) in recent years due to the miniaturization and cost reduction of the multicolor image forming apparatus.

Conventionally, in color printers, the deviation of the inclination of each color in a printed image has been a major problem.

When the inclination deviation G occurs, as shown in FIG. 9, for example, when black (Bk) and magenta (M) are overlaid, the inclination of the photosensitive drum between the respective colors and the relative displacement with respect to the photosensitive drum The tilt of the scanner unit appears directly in the image.

In other words, when the axes of the four photoconductor drums are broken, tilt deviation G occurs in each color on the printed image. When the parallelism of the optical axis of the scanner unit with respect to the axis of each photoconductor drum is broken, tilt deviation G is similarly generated for each color on the printed image.

Further, the scanner unit has a polygon motor (not shown) inside and serves as a vibration source. In order to suppress the vibration of the scanner unit itself, it is necessary to firmly attach it to the body frame.

Conventionally, the scanner unit 20 as shown in FIG.
No. 2 was fixed to the scanner base 205 with a screw and firmly fixed. The flatness of the scanner base is strictly regulated, and measures have been taken to improve the accuracy of parts and the strength of parts by increasing the plate thickness to increase rigidity.

In the above means, there is a limit in strictly defining the accuracy of parts and guaranteeing the position. The amount of color misregistration allowed in a color printer is generally said to be 100 μm, and among various factors of color misregistration, it was necessary to suppress the amount of color misregistration to several tens of μm in the main body configuration. Therefore, each component must be manufactured with an accuracy of several μm, and unrealistic dimensional regulation is required for the scanner base 205.

Further, four scanner stands are required, and the scanner unit is fastened with four or more screws in order to suppress vibration, which leads to an increase in cost.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to improve the assemblability and to provide an image capable of accurately supporting and fixing the scanner unit at low cost. To provide a forming apparatus.

[0019]

In order to achieve the above object, in the present invention, an image carrier, a scanner unit for emitting a beam toward the image carrier, the image carrier and the scanner. An image forming apparatus including a frame supporting a unit, the supporting member having a biasing unit fixed to the frame and biasing the scanner unit toward a positioning portion provided on the frame. It is characterized by including.

The supporting member is provided through a gap with respect to the scanner unit biased toward the positioning portion, and when the scanner unit moves against the biasing force of the biasing means. In addition, it is also preferable to include a restriction portion that restricts the movement of the scanner unit.

It is also preferable that the gap is set to 2 mm or less.

It is also preferable that the support member is detachably attached to the frame body.

It is also preferable that the support member is swingably provided with respect to the frame body.

The supporting member is a sheet metal, and the urging means is a tension coil spring, and substantially both ends of the tension coil spring are engaged with the sheet metal, and the substantially central portion of the tension coil spring is the scanner unit. It is also preferable to exert the biasing force by contacting the curved portion provided on the.

It is also preferable that a plurality of the image bearing members and the plurality of the scanner units are provided respectively, and that the support member is provided with a plurality of biasing means for respectively biasing the plurality of scanner units.

A plurality of the image carriers are arranged in a substantially vertical direction, the scanner unit is arranged in a substantially horizontal direction of each of the plurality of image carriers, and the sheet feeding unit is arranged below the image carrier. Section, a fixing section arranged above the image carrier, and an electrostatic transfer belt unit which is in contact with all the image carriers and conveys the transfer material fed from the paper feeding section to the fixing section. It is also preferable to include a swing shaft that is provided below the scanner unit and that allows the support member to swing with respect to the frame body.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement of them should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions, and the scope of the invention is not limited to the following embodiments.

First, the overall structure of the multicolor image forming apparatus will be outlined with reference to FIG. FIG. 1 is a vertical cross-sectional view showing an entire configuration of a full-color laser beam printer 100 which is one mode of a multicolor image forming apparatus.

The multicolor image forming apparatus 100 shown in the figure includes four photoconductor drums 1 (1a, 1b, 1c, 1d) arranged vertically as image carriers.

The photosensitive drum 1 is rotationally driven counterclockwise in the figure by a drive means (not shown).

Around the photosensitive drum 1, a charging device 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction thereof, and a laser beam is irradiated based on image information. The scanner unit 3 (3a, 3b, 3c, which forms an electrostatic latent image on the photosensitive drum 1)
3d), a developing device 4 (4a, 4b, 4c, 4d) for adhering toner to the electrostatic latent image to develop it as a toner image, and an electrostatic transfer device for transferring the toner image on the photosensitive drum 1 to the transfer material S. 5. Cleaning device 6 (6a, 6b, 6) for removing transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer
c, 6d) and the like are provided.

Here, the photosensitive drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are integrally made into a cartridge to form a process cartridge 7.

Hereinafter, the photosensitive drums 1 will be described in detail.

The photosensitive drum 1 is constituted by coating an organic photoconductive layer (OPC photosensitive member) on the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Photoconductor drum 1
Has both ends rotatably supported by support members, and is driven to rotate counterclockwise by transmitting a driving force from a drive motor (not shown) to one end.

As the charging device 2, a contact charging type device can be used. The charging member is a conductive roller formed in the shape of a roller. The roller is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the roller to make the surface of the photosensitive drum 1 uniform. It is to be charged.

The scanner unit 3 is arranged substantially in the horizontal direction of the photosensitive drum 1 and has a laser diode (not shown).
The image light corresponding to the image signal is rotated at a high speed by a scanner motor (not shown) by the polygon mirror 9
(9a, 9b, 9c, 9d) is irradiated. The image light reflected by the polygon mirror 9 is formed by the imaging lens 10 (10a,
10b, 10c, 10d), the surface of the charged photosensitive drum 1 is selectively exposed to form an electrostatic latent image.

Each of the developing devices 4a, 4b, 4c and 4d is composed of a developing device in which toners of respective colors of yellow, magenta, cyan and black are stored.

Then, all the photosensitive drums 1a, 1a
b, 1c, 1d facing each other and moving cyclically to contact
An electrotransfer belt 11 is arranged. The electrostatic transfer belt 11
10¹¹ -10¹⁴Thickness with volume resistivity of Ω · cm
It is composed of a film-shaped member having a thickness of about 150 μm.

The electrostatic transfer belt 11 has a vertical direction of 4
The transfer material S is electrostatically adsorbed on the outer peripheral surface on the left side in the drawing by a shaft and is circulated to contact the transfer material S with the photosensitive drum 1. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the toner image on the photosensitive drum 1 is transferred.

Abutting on the inside of the electrostatic transfer belt 11,
The transfer roller 12 (12a, 12b, 12c, 12) is provided at a position facing the four photoconductor drums 1a, 1b, 1c, 1d.
d) are installed side by side. A positive charge is applied from the transfer roller 12 to the transfer material S through the electrostatic transfer belt 11, and an electric field generated by the charge causes a negative charge on the photosensitive drum 1 on a sheet in contact with the photosensitive drum 1. Toner image is transferred.

The electrostatic transfer belt 11 has a circumference of about 700 mm,
The belt has a thickness of 150 μm and is wound around four rollers of a driving roller 13, driven rollers 14a and 14b, and a tension roller 15, and rotates in the direction of the arrow in the figure. As a result, the toner image is transferred while the above-mentioned electrostatic transfer belt 11 circulates and the transfer material S is conveyed from the driven roller 14a side to the drive roller 13 side.

The paper feed section 16 is arranged below the photosensitive drum 1 and feeds and conveys the transfer material S to the image forming section. A plurality of transfer materials S are stored in the paper feed cassette 17. ing. During image formation, the paper feed roller 18 (half-moon roller),
The registration roller pair 19 is driven and rotated in accordance with the image forming operation to separate and feed the transfer materials S in the paper feed cassette 17 one by one, and the leading end of the transfer material S abuts against the registration roller pair 19 and is temporarily stopped. After the formation, the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized with each other, and the registration roller pair 19 feeds the image onto the electrostatic transfer belt 11.

The fixing section 20 is disposed above the photosensitive drum 1 and fixes the toner images of a plurality of colors transferred to the transfer material S, and is in contact with the rotating heating roller 21a and is pressed against it. And a pressure roller 21b for applying heat and pressure to the transfer material S.

That is, the transfer material S onto which the toner image on the photosensitive drum 1 is transferred is conveyed by the fixing roller pair 21 when passing through the fixing section 20, and is given heat and pressure by the fixing roller pair 21. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.

In the image forming operation of the image forming section, the process cartridge 7 (7a, 7b, 7c, 7d) is sequentially driven in accordance with the printing timing, and the photosensitive drums 1a, 1b, 1c, 1d is driven to rotate counterclockwise. Then, the scanner unit 3 corresponding to each process cartridge 7 is sequentially driven.

By this driving, the charging roller 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1, and the scanner unit 3 exposes the peripheral surface of the photosensitive drum 1 in accordance with an image signal to expose it. An electrostatic latent image is formed on the peripheral surface of the body drum 1.

The developing roller in the developing device 4 transfers toner to the low potential portion of the electrostatic latent image to form (develop) a toner image on the peripheral surface of the photosensitive drum 1.

At the timing when the front end of the toner image on the peripheral surface of the photosensitive drum 1 in the most upstream position is rotatably conveyed to the point of opposition to the electrostatic transfer belt 11, the print start position of the transfer material S is set at the point of opposition. The registration roller pair 19 starts rotating to feed the transfer material S to the electrostatic transfer belt 11 so that

The transfer material S is pressed against the outer circumference of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic transfer roller 22 and the electrostatic transfer belt 11, and between the electrostatic transfer belt 11 and the electrostatic transfer roller 22. A voltage is applied to the transfer material S, which is a dielectric, to induce an electric charge in the dielectric layer of the electrostatic transfer belt 11, and the transfer material is electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. ing. As a result, the transfer material S
Is stably attracted to the electrostatic transfer belt 11 and is conveyed to the most downstream transfer unit.

While being conveyed in this way, the transfer material S sequentially transfers the toner images on the respective photosensitive drums 1 by the electric field formed between the respective photosensitive drums 1 and the transfer roller 12.

The transfer material S on which the four color toner images have been transferred is
Due to the curvature of the belt driving roller 13, the electrostatic transfer belt 11
Are separated from each other by a curvature, and are carried into the fixing unit 20. Transfer material S
After the toner image is heat-fixed by the fixing section 20, the sheet is discharged from the sheet discharging section 24 to the outside of the main body by the sheet discharging roller pair 23 with the image surface facing down.

Next, the main body frame supporting the scanner unit 3 will be described with reference to FIG.

As shown in FIG. 2, bearings 31 (31a, 31a) are provided at both ends of the photosensitive drum 1 in the longitudinal direction (two-dot chain line).
b) (Bearing) is fitted and rotatably attached. The bearing 31 is axially restricted by an E ring (not shown). In FIG. 2, only the photosensitive drum 1 and the bearing 31 are shown for the sake of easy understanding of the configuration of the present invention. However, in the color printer of the present embodiment, as described in the overall configuration, the charging unit and the developing unit are used. The cartridge and the cleaning means are integrally formed (see FIG.
It becomes the composition of 7).

Further, the left and right side plates 32 (the left side plate 32a, the right side plate 32b) are positioned so as to come into contact with the outer peripheral surface of the bearing 31.
Are arranged.

The left and right side plates 32 are bent outward at their lower portions, and are fastened to the bottom plate 33 with screws from above. The pitch between the left and right side plates is an important dimension, and in order to regulate the pitch, the dimension in the width direction of the bottom plate 33 and the parallelism of the left and right side plate positioning portions are strictly regulated. Like the left and right side plates 32, the bottom plate 33 is formed of sheet metal, and has a sheet passage hole 33a on the front side so that a sheet can pass therethrough.

The left and right side plates 32 have a bent shape on the front surface (on the side where the photoconductor drum is inserted) so as to have rigidity as a single component. Further, the left and right side plates 32 are provided with eight first opening holes 34 (34a to 34h) so as to cover the bent portions. The first opening hole 34 is used for positioning the photosensitive drum 1. As shown in FIG. 2, the bearing 31 is composed of a ball bearing, and is positioned by pressing it against the abutting surface of the first opening hole 34.

Further, on the same plane of the first opening hole 34 and in the substantially horizontal direction, the second opening holes 35 (35a-35) are formed.
h) is open. The second opening hole 35 is used for positioning the scanner unit 3, which is a characteristic part of the present invention. The scanner unit 3 is also the same as the photosensitive drum 1.
Positioning is performed by pressing against the abutting surfaces 38 and 39 (FIG. 4) as positioning portions.

The left and right side plates 32 are provided on the back side of the left and right side plates 32.
The rear stay 36 is positioned so as to straddle over and is fastened with screws. In the rear stay 36, a third opening hole 37 (37a) is formed substantially horizontally with the two opening holes 34, 35.
~ 37d) have been opened. The third opening hole is also used for positioning the scanner unit 3.

Here, the left and right side plates 32 (the left side plate 32a, the right side plate 32b), the bottom plate 33, and the rear stay 36 constitute a main body frame as a frame body.

Next, the method of pressing and positioning the scanner unit, which is a feature of the present invention, will be described in detail with reference to FIGS. Figure 3 shows the scanner unit 3 on the body frame.
Fig. 4 is a left side view showing a state in which the
Is a partially enlarged view.

The second opening 3 formed in the left side plate 32a
5 (35a to 35d), the protrusion 41 of the scanner unit 3 projects from the left side plate 32a to the outside (toward the front side in FIG. 3). An arc-shaped portion 41a as a curved portion is formed at one end of the protrusion 41.

A coil spring 42 as a biasing means is hung on the arc-shaped portion 41a so as to come into contact therewith with a wrapping angle.

The arc-shaped portion 41a is provided to prevent the coil spring 42 from being caught, and in the present embodiment, the scanner unit 3 is made of resin.
By increasing the contact area between the resin scanner unit 3 and the coil spring 42, the resin damage due to the spring force is also reduced.

The coil springs 42 (42a to 42d) are tension coil springs, and each scanner unit 3
(3a to 3d) are arranged. Coil spring 4
2 (42a to 42d) are supported by the support member 43 in a state of resisting the spring force.

The support member 43 is supported below the scanner unit 3 so as to be swingable about a (swing) shaft 46 crimped to the left side plate 32a. It is preferable that the support member 43 is detachably provided on the left side plate 32a. Further, a protrusion 47 is formed by bending and bending above the left side plate 32a. This is used for temporarily fixing the support member 43 when it is about to rotate due to the spring force.

Next, the attachment of the coil spring 42 and its function will be described with reference to FIG.

The supporting member 43 is made of a metal plate of 1 mm, and is provided with a bent and bent portion at a position sandwiching the protruding portion 41 of the scanner unit 3 positioned on the left and right side plates. The bent and bent portion is provided with hook portions 45 (45a, 45b) capable of hooking the spring ends, and both ends of the coil spring 42 are easily attached by being hooked on the hook portions 45 (45a, 45b). .

In this state, the coil springs 42 are subjected to tensile forces F1 and F2 as shown in FIG.
The resultant force of 1 and F2, F in the figure, acts on the protrusion 41.
This force F ensures that the protrusion 41 of the scanner unit 3 abuts against the abutting surfaces 38, 39. In this embodiment, F is set to be about 2 kgf (19.6 N).

FIG. 5 is a schematic top view of the image forming apparatus main body. The fixing means of the scanner unit 3 described so far is outside the left side plate 32a, and the right side plate 32b.
It is also installed outside the. Also, the back stay 36
It may be installed in.

As a result, the scanner unit 3 can be reliably abutted and positioned on the abutting surfaces 38, 39 of the left and right side plates 32, and the positional accuracy with respect to the photosensitive drum 1 which is important is improved. Further, by swinging the support member 43 around the shaft 46, the respective coil springs 42 can be brought into contact with the respective protruding portions 41, so that the four scanner units 3 (3a to 3d) are fixed at the same time. And the assemblability is improved.

Next, the detailed shape of the support member 43 will be described with reference to FIG.

The support member 43 has stopper surfaces 48 and 49 as restricting portions on the side facing the abutting surfaces 38 and 39. The stopper surfaces 48, 49 are set at positions where a gap of g is opened from the end surface of the protrusion 41, and serve as stoppers when the scanner unit 3 moves due to impact. The gap g is preferably 2 mm or less, and in the present embodiment, the gap g is set to 1 mm, and the movement of the scanner unit 3 is restricted by the stopper surfaces 48 and 49 when a shock is applied during distribution. Plastic deformation of the coil spring 42 is prevented.

Here, the impact value during distribution may be as high as 30G. This impact value will not be a problem if the screw is fixed as in the conventional case, but considering the pressing force of the scanner unit 3 by the spring, a spring pressure of about 10 kgf (98 N) is required, and the protrusion of the scanner unit 3 is required. Damages 41. Also, a 10 kgf (98 N) spring is difficult to actually assemble.

Therefore, in the present embodiment, the stopper surface 4
By providing 8, 49, the movement of the scanner unit 3 when a shock is applied is regulated. This eliminates the need to set the spring pressure higher than necessary. If the minimum pressure is set so that the scanner unit 3 can be returned to its original position when it is displaced, the spring pressure can be set easily without damaging the scanner unit 3.

Next, the actual assembly procedure will be described with reference to FIG.

First, the scanner unit 3 is set on the body frame, and in that state, the coil springs 42 (42a to 42a) are set.
The support member 43 to which d) is attached is fitted on the shaft 46.
The E-ring (not shown) is stopped so that the support member 43 does not come off the shaft 46. Since the spring force does not work in this state, the support member 43 is swingably supported by the left side plate 32a.

Next, the support member 43 is rotated and set in the direction of the arrow in the figure while resisting the spring force to a position beyond the bend-up 47 of the left side plate 32a. At that time, as described above, since the projection 41 has the arc-shaped portion 41a, the spring can be set without being caught.

At that position, the screw is stopped at one place and the supporting member 4
By fixing 3 to the left side plate 32a, the fixing of the left side of the scanner unit 3 is completed. The right side plate 32b side is also fixed in the same manner to complete the fixing of the scanner unit.

In the present embodiment, the parts are attached by rotating the support member 43 while resisting the spring force, so that a large reaction force can be easily applied for assembly. Therefore, set the pressure spring of each of the four scanner units to 1
It is possible to set in degrees. Further, since the assembling is easy and the disassembling can be done by a simple operation, when the scanner unit 3 needs to be replaced, it can be attached and detached in a short time.

In this embodiment, the left and right side plates 32 (32a, 32a,
Although it is arranged on the outer side of 32b), it can also be fixed by arranging it on the inner side of the left and right side plates 32.

With the above-described structure, the scanner unit 3 is supported by the main body frame at three points, and is positioned and supported by a spring bias without fastening with screws.

Therefore, the conventional scanner base and screws are not required, the assembling property can be improved, the number of parts can be reduced, the cost can be reduced, and the weight of the apparatus main body can be reduced. Further, the scanner unit 3 is not affected by the distortion when the screws are fixed, and the scanner unit 3 exhibits stable performance even when the apparatus main body is installed on the uneven floor surface and the apparatus main body is distorted. You can Further, the main body frame for positioning and supporting the photosensitive drum 1 is provided with a positioning portion for positioning the scanner unit 3, and is biased toward the positioning portion by the biasing means, so that the scanner unit 3 is accurately supported and fixed. can do.

Further, by providing the support member 43 with the abutting surfaces 38, 39 having a clearance of 2 mm or less with the scanner unit 3, the scanner unit 3 can abut the abutting surfaces 38, 39 even when a large impact is applied during distribution. By contacting 39, it does not move more than necessary, the coil spring 42 is not plastically deformed, and even if the scanner unit 3 shifts, it can return to its original position by the spring. Therefore, the scanner unit and the urging means are not damaged. Also, since it is not necessary to press with more force than necessary, it does not damage the scanner unit,
Assembly is also easy.

Further, since the support member 43 is attached and detached, the support member 43 is swingable so as to be retracted from the scanner unit 3 with respect to the mounting position, so that the assembly can be easily performed.
The serviceability of scanner replacement is improved.

Further, the supporting member 43 is made of sheet metal, and the biasing means is made of a tension coil spring, and both ends of the coil spring 42 are engaged with the supporting member 43 so that the substantially central portion of the spring is an arc of the scanner unit 3. By bringing the scanner unit into contact with the shape unit, the scanner unit can be supported at low cost without damaging the scanner unit.

[0086]

As described above, according to the present invention,
Since the conventional scanner stand and screws are not required, it is possible to improve the assemblability and simplify the configuration, and it is possible to provide an image forming apparatus that can accurately support and fix the scanner unit at low cost. Becomes

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic side view showing an image forming apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining a supported state of the scanner unit according to the embodiment of the present invention.

FIG. 5 is a schematic top view showing an image forming apparatus according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining a fitted state of a scanner unit and a support member.

FIG. 7 is a diagram for explaining an assembly procedure.

FIG. 8 is a schematic perspective view showing a conventional image forming apparatus.

FIG. 9 is a diagram showing a color shift image.

FIG. 10 is a schematic sectional view showing a conventional image forming apparatus.

[Explanation of symbols]

1 photoconductor drum 2 Charging device 3 Scanner unit 4 Developing device 5 Electrostatic transfer device 6 cleaning device 7 Process cartridge 9 polygon mirror 10 Imaging lens 11 Electrostatic transfer belt 12 Transfer roller 13 Drive roller 14a, 14b driven roller 15 Tension roller 16 paper feeder 17 Paper feed cassette 18 Paper feed roller 19 Registration roller pair 20 fixing unit 21 Pair of fixing rollers 22 Electrostatic attraction roller 23 Paper ejection roller pair 24 Paper output section 31 bearing 32 Left Right Plate 33 Bottom plate 33a Paper feed hole 34,35,37 Open hole 36 Rear stay 38,39 abutting surface 41 Projection 41a Arc-shaped part 42 coil spring 43 Support member 45 Hook part 46 axes 47 Projection 48,49 Stopper surface 100 full color laser printer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomoyuki Araki             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 2C362 AA10 AA45 CA18 CA22 DA04                 2H071 BA03 BA04 BA16 DA02 DA06                       DA08 DA13 DA15 EA18                 2H076 AB02 EA01 EA11 EA24

Claims (8)

[Claims] 1. An image forming apparatus comprising: an image carrier; a scanner unit that emits a beam toward the image carrier; and a frame body that supports the image carrier and the scanner unit. An image forming apparatus comprising: a support member fixed to a body and having a biasing unit that biases the scanner unit toward a positioning portion provided on the frame. 2. The supporting member is provided via a gap with respect to the scanner unit biased toward the positioning portion, and the scanner unit moves against the biasing force of the biasing means. If you do
The image forming apparatus according to claim 1, further comprising a restriction portion that restricts movement of the scanner unit. 3. The image forming apparatus according to claim 2, wherein the gap is set to 2 mm or less. 4. The image forming apparatus according to claim 1, wherein the support member is detachably provided on the frame body. 5. The image forming apparatus according to claim 1, wherein the support member is swingably provided with respect to the frame body. 6. The supporting member is a sheet metal, and the urging means is a tension coil spring, and substantially both ends of the tension coil spring are engaged with the sheet metal, and a substantially central portion of the tension coil spring is provided. 6. The image forming apparatus according to claim 1, wherein the biasing force is exerted by abutting a curved portion provided on the scanner unit. 7. The image carrier and the scanner unit are provided in a plurality respectively, and the support member is provided with a plurality of urging means for urging the plurality of scanner units, respectively. The image forming apparatus according to claim 1. 8. A plurality of the image carriers are arranged in a substantially vertical direction, the scanner unit is arranged in a substantially horizontal direction of each of the plurality of image carriers, and is arranged below the image carrier. A paper feeding unit, a fixing unit arranged above the image carrier, and an electrostatic transfer belt which is in contact with all the image carriers and conveys the transfer material fed from the paper feeding unit to the fixing unit. The image forming apparatus according to claim 7, further comprising: a unit; and a swing shaft that is provided below the scanner unit and that allows the support member to swing with respect to the frame body.