JPH09236772A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide structure for preventing a polygon mirror from falling and being damaged when a polygon motor is turned upside down as an image forming unit is turned and surely preventing the polygon mirror from falling in the case of the polygon motor whose polygon mirror falls when it is turned bottom up like an oil dynamic pressure bearing. SOLUTION: In this image forming device; the proper part of the end of a turning unit equipped with the image forming unit and a write device 21 is pivotally supported to freely turn in an up-and-down direction with reference to an image forming device main body, and the polygon motor 19 in the device 21 is turned bottom up when the turning unit located inside the device main body is turned to be on the outside of the device main body. A presser member 42 is provided at the upper part of the polygon mirror 30 whose shaft center is supported by the output shaft 40 of the motor 19 so as to prevent the polygon mirror 30 from falling off from the output shaft even when the motor 19 is turned bottom up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an image forming apparatus using a writing device using a polygon mirror such as a laser beam printer, a digital copying machine, a plain paper facsimile machine, and the like. The present invention relates to an image forming apparatus in which a polygon mirror in a writing device is prevented from falling from a polygon motor in a device in which a writing device portion is pivotally supported in a vertical direction with respect to a main body of the device so as to be able to turn upside down.

[0002]

2. Description of the Related Art In an image forming apparatus equipped with a writing device using a polygon mirror, such as a laser beam printer, a digital copying machine, a plain paper facsimile, etc., an output shaft of a polygon motor is used as an axis. A polygon mirror serving as a rotating polygon mirror having a supported core is irradiated with laser light from a laser diode for deflection scanning, and is irradiated onto a photoconductor through a lens, a mirror, and the like. The electrostatic latent image formed by irradiating the photoconductor is visualized by a well-known electrophotographic process, and transferred and fixed on a transfer paper. As described below, the present invention relates to an image forming apparatus having a structure in which an image forming unit including a writing device is pivotally supported in a vertical direction with respect to a main body of the device. In order to facilitate maintenance of the image forming unit including the image forming unit, the image forming unit is rotated 180 degrees and taken out to the outside of the apparatus main body, so that the maintenance is possible with the lower surface side of the image forming unit exposed. . A problem with this type of image forming apparatus is that when the image forming unit is turned upside down, the polygon mirror forming the writing device falls off the shaft of the polygon motor. Depending on the type of bearing of the polygon motor, in an oil dynamic pressure bearing or an air bearing (one that is not magnetically levitated), the polygon mirror will surely fall off the motor shaft when it is turned upside down, or the position will be displaced. Further, as the axis of the polygon motor rotating at a high speed changes its direction from vertical to horizontal due to the upside down rotation of the image forming unit, the load on the axis increases, resulting in polygon failure and shortened life. Will bring.

[0003]

[Problems to be Solved by the Invention] JP-A-60-2643
The "Motor Unit" (Cannon) of Japanese Patent No. 2 discloses a technique of preventing a damage due to a mishandling during transportation by bringing a pressing member into contact with an upper end of a rotary sleeve having a polygon mirror attached thereto. In the actual use, the pressing member is separated by the rotation of the polygon motor. However, since this conventional technique is merely intended to prevent the polygon mirror from being damaged during transportation, the polygon motor is rotated when the writing unit is used and the holding member is once detached, and then the detached state is maintained. Becomes
Therefore, when the pressing structure of the polygon mirror is applied to the writing device of the image forming apparatus on which the present invention is based, it is impossible to prevent the polygon mirror from falling off the polygon motor shaft due to the upside down.

The present invention has been made in view of the above, and the invention of claim 1 is to rotate the image forming unit in the vertical direction in order to improve workability during maintenance and jam processing, and in front of the device. In the image forming apparatus that is pulled out to the side, the polygon model is moved along with the rotation of the image forming unit.
Prevents the polygon mirror from falling and being damaged when the tape is turned upside down. In particular, it is an object of the present invention to provide a structure capable of reliably preventing the polygon mirror from falling even in a polygon motor such as an oil dynamic pressure bearing in which the polygon mirror falls when inverted.
In the present invention, the upper portion of the polygon motor is not brought into contact with the pressing member for preventing the polygon mirror from falling, so that the polygon motor is not loaded during the rotation of the polygon.
Moreover, when the polygon motor is turned upside down, the polygon mirror is prevented from falling and being damaged. That is,
By preventing the polygon motor and the pressing member from contacting each other while the polygon is rotating, it is possible to prevent an excessive load from being applied to the polygon motor, and to prevent a failure or a reduction in life.

According to a third aspect of the present invention, in the invention according to the first and second aspects, the pressing member is integrally molded with the writing device cover, so that the polygon model is rotated along with the rotation of the image forming unit.
The polygon mirror is prevented from falling when the machine is turned upside down, and the pressing member is integrated with existing parts instead of being a separate part, reducing the number of parts and improving the assemblability, thus improving productivity. The purpose is to raise costs and reduce costs. According to a fourth aspect, in the invention according to the third aspect, the outer cover is provided by the writing device cover integrally molded with the pressing member.
This function also prevents the polygon mirror from falling and being damaged when the polygon motor is turned upside down due to the rotation of the image forming unit, and the pressing member is integrated with existing parts instead of being a separate part. By reducing the number of parts,
The purpose is to improve assemblability, productivity, and cost reduction.

According to a fifth aspect of the present invention, in the invention according to the first and second aspects, the pressing member is a noise prevention cover of the polygon motor.
With this structure, the polygon mirror is prevented from falling when the polygon motor is turned upside down due to the rotation of the image forming unit, and the pressing member is integrated with the existing part instead of being a separate part. , The number of parts is reduced, the assemblability is enhanced, the productivity is enhanced, and the cost is further reduced. According to a sixth aspect of the present invention, in the invention according to the second to fifth aspects, a friction member is provided at a portion of the pressing member that comes into contact with the polygon motor shaft, so that the polygon motor is turned upside down as the image forming unit rotates. At the same time, it is intended to prevent the polygon mirror from dropping and being damaged, and to stop the rotation of the polygon mirror early by contact between the polygon mirror and the friction member to suppress noise. According to a seventh aspect of the invention, in the invention according to the sixth aspect, since the friction member is integrated with the pressing member, when the polygon motor is turned upside down as the image forming unit rotates,
The polygon mirror is prevented from falling and being damaged, and the rotation of the polygon mirror is stopped by the contact between the polygon mirror and the friction member to suppress noise. By integrally forming the friction member and the pressing member, the number of parts can be reduced and the assembling can be improved.
The purpose is to reduce costs.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and the invention according to claim 1 provides an image forming apparatus in which an end portion of a rotary unit having an image forming unit and a writing device is located at an appropriate position. The polygon motor in the writing device is turned upside down when it is pivotally supported in the up-down direction with respect to the main body, and when the rotary unit located inside the main body of the apparatus is rotated and brought out of the main body of the apparatus. In the image forming apparatus, a pressing member is provided above the polygon mirror whose axis is supported by the output shaft of the polygon motor so that the polygon mirror does not drop off from the output shaft even when the polygon motor is turned upside down. It is characterized in that it is configured in. According to a second aspect of the present invention, the upper portion of the output shaft of the polygon motor and the lower portion of the pressing member are opposed to each other with a predetermined gap so that they do not contact each other during normal operation. According to a third aspect of the present invention, the pressing member has an integral structure with a writing device cover that closes an opening provided in the upper portion of the housing of the writing device. The invention of claim 4 is
The writing device cover having an integral structure with the pressing member also serves as an exterior cover of the rotating unit. According to a fifth aspect of the present invention, the pressing member is integral with a noise prevention cover that seals the polygon motor. The invention of claim 6 is characterized in that a friction member is provided at a portion where the pressing member comes into contact with the output shaft of the polygon motor. The invention of claim 7 is characterized in that the friction coefficient of the portion where the pressing member comes into contact with the output shaft of the polygon motor is increased.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. <Description of Image Forming Apparatus to which the Present Invention is Applied> FIG.
2B is an external view and a side cross-sectional view of an example of an image forming apparatus to which the present invention is applied, and FIGS. 2A and 2B are views showing a rotating state and a rotating completed state of the image forming apparatus. is there. This image forming apparatus is related to the proposal of the present applicant, 1 is an image forming unit (image forming section), 2 is a sheet discharging section, 3 is a sheet conveying section,
Reference numeral 4 denotes a paper feeding unit, 5 denotes a table unit, 6 denotes an operation display unit, 7 denotes a scanner unit, and 8 denotes an upper space. In this image forming apparatus, the image forming unit (image forming unit) 1 is provided above the paper feeding unit 4, the paper discharge unit 2 is provided on the back side of the image forming unit 1, and the sheet discharging unit 2 is provided above the image forming unit 1. -The upper space 8 for discharging each is disposed. Since the operation display unit 6 and the scanner unit 7 are arranged above the paper discharge unit 2, a multifunctional image forming apparatus can be provided without increasing the installation area. 1B is a schematic diagram of the internal configuration of the apparatus shown in FIG. 1A, in which the transfer paper fed from the paper feed unit 4 passes through the path of arrow A,
The paper is conveyed to the paper discharge unit 2 and the upper space 8. Imaging unit 1
A laser beam writing device 21 is incorporated in the upper part of the image forming unit 1, and the image forming unit 1 and the writing device 21 are integrated with each other, and an arrow B is formed on the main body of the device about the rotation fulcrum 10.
It is supported so as to be rotatable in any direction (vertical direction or front-back direction). Hereinafter, a unit including the image forming unit 1 and the writing device 21 is referred to as a rotating unit 20.

The boundary between the lower part of the rotating unit 20 and the main body of the apparatus (sheet conveying section 3) is a sheet feeding line indicated by an arrow A, and below the sheet feeding line A (sheet conveying section 3 side). The lower fixing roller 13a, the lower registration roller 14a, and the transfer roller 16 are arranged. Above the paper feed line A (on the side of the rotation unit 20), the toner cartridge 11, the photosensitive drum 12, the fixing roller 13b, the registration roller 14b, the developing device 15, the cleaning roller 17, the charging roller 18, and the above A polygon motor 19 and the like which form the writing device 21 are arranged. In the image forming operation by the image forming apparatus, as shown in FIG. 3, the original image read by the scanner unit 7 is temporarily transferred to a CCD (not shown).
After the image is formed on the image, the image information obtained by the photoelectric conversion is digitally converted and then subjected to predetermined processing by the image processing unit or the like,
The laser diode 22 emits light according to the image-processed signal. The laser beam from the laser diode (LD unit) 22 is applied to the polygon mirror 30 that rotates at high speed via the cylinder lens 23, and the main scanning is performed.
It is irradiated onto the photoconductor 12 via the lens 24, the mirror 25, and the like. Even in the conventional image forming apparatus, there are those in which the respective units are stacked to reduce the installation area, but in the conventional apparatus, the image forming unit is arranged at the back of the apparatus,
Maintenance around the image forming unit is difficult to perform, and there is a drawback in that it imposes a burden on the user. Also, for maintenance, the cover is opened from the side or back to expose the inside of the device, so it is necessary to secure a space for maintenance around the device or move the device to secure a space before performing maintenance. was there.

FIGS. 2A and 2B show the operation of the image forming apparatus of the present invention during maintenance. When performing maintenance, the rotation unit 20 is integrally rotated in the front of the apparatus using the upper space 8 as shown in (a). Rotating unit 2
By turning 0, the sheet conveying section 3 is opened so that maintenance can be performed from the front of the apparatus as shown in (b). This enables maintenance work such as removal of jammed paper and cleaning of guide plates and various rollers forming the transport path to be comfortably performed in a wide working space. Moreover, since the transfer paper conveyance direction and the maintenance direction are the same, it is easy to apply a force for pulling out the transfer paper, and there is no risk of tearing the transfer paper. Rotating unit 2 as shown in Fig. 2 (b)
After 0 has rotated, it moves to the front of the main body of the device in a state where the top and bottom are reversed. Therefore, the image forming unit 1, which is originally located at the innermost position of the apparatus main body, is located outside, which makes maintenance very easy. Further, since the surface on the sheet transfer section side where other peripheral parts are not normally arranged is opened upward, maintenance work such as parts replacement and cleaning from the upper part can be carried out very comfortably.

In the conventional maintenance operation, the operation procedure often differs greatly depending on the type of maintenance. Particularly, in order to remove jammed paper, the exposure procedure of the conveyance path and the maintenance procedure such as supply replenishment of the image forming unit 1 are greatly different in the sheet conveying path and the image forming unit 1 having the conventional configuration, The users who do this were often confused. However, in the present invention, various necessary maintenances can be undertaken by a common and one-time operation of rotating the image forming unit 1 forward, so that the operation start procedure may be erroneously performed again. It is possible to avoid wasting time for checking a manual or the like to know the operation procedure. Further, since the exposing means for maintenance can be made common, it is obvious that it contributes to downsizing and cost reduction of the device. In this image forming apparatus, a two-joint link is used as the rotation fulcrum 10 in order to prepare a wide maintenance space by rotating about 180 degrees (FIG. 4). Since only the front of the equipment is used as the maintenance space, it is not necessary to prepare extra space on the side or back. In the above description, only the electrophotographic image forming apparatus has been described as an example, but the method is not limited, and any image forming apparatus of various types may be used to form an image from above the sheet conveying unit. The above effects can be obtained similarly.

<Writing Device> FIG. 4 is a schematic view showing the pivotal support structure of the rotating unit. The writing device 21 has a writing device cover 32 for opening an upper opening of a housing 31 in which optical parts such as a polygon motor are arranged. A turning unit cover 33 is arranged in the opening of the turning unit 20 which is closed and located directly above the writing device. Figure 5 (a)
(b) and (c) show changes in the posture of the polygon motor 19 when the rotating unit 20 rotates, and the rotating unit 20 rotates about the two-joint link 10 as a fulcrum during maintenance or jam processing. Therefore, when rotated 180 degrees from the normal operation, the polygon motor 19 is turned upside down.

<Conventional Bearing Structure and Its Defects> FIG. 6 (a)
(b) and Fig. 7 show the types of polygon bearings,
For example, in the ball bearing type shown in FIG. 6 (a), the dynamic pressure air bearing type shown in FIG. 6 (b), and the magnetic fluid bearing type polygon illumination shown in FIG. 7, even if the polygon motor is turned upside down, Will fall from the motor shaft, causing misalignment and damage. On the other hand, even in the case of the oil dynamic pressure bearing type or the dynamic pressure air bearing type, if the polygon motor is turned upside down without using the magnetic bearing in the axial direction, the polygon mirror will fall. It will be. The advantage of the oil dynamic pressure bearing over the air bearing is that the oil is strong against compression and generates sufficient dynamic pressure at a relatively low speed, and the bearing gap becomes relatively large.
The point is that the precision of the groove, which is a fine groove formed in the sleeve for generating the dynamic pressure, can be rough.
A drawback of the hydraulic fluid pressure bearing type having such superiority is that when the polygon motor is turned upside down, the polygon mirror falls, causing a position shift or damage. A writing device suitable for the image forming apparatus of the above-mentioned type cannot be produced unless such a drawback is solved, but such problems can be solved by the embodiment described below.

<First Embodiment> FIG. 8 is a cross-sectional view of an essential part showing a polygon bearing structure according to the first embodiment of the present invention. Inside the rotary unit cover 33 for closing the upper part of the rotary unit. Although the writing device cover 32 is located in this example, in this embodiment, the holding member 42 is provided via the bearing 41 attached so as to be in contact with the outer circumference of the output shaft 40 of the polygon motor 19. Fix the vertical direction. Specifically, the pressing member 42 is fixed to the lower surface of the writing device cover 32, and the upper surface of the bearing 41 is pressed (fixed) by the protrusion 42 a of the pressing member 42, and the bearing 41 is also fixed.
Is a flange portion 40a at the bottom of the output shaft 40 at the base thereof.
It is configured to touch the top. Therefore, the axial movement of the polygon mirror 30, which is in a state where it can be detached from the shaft 40 in the manual axis direction, can be completely restricted. In this first embodiment, a ball bearing is used as the bearing to make contact with the output shaft. However, in the polygon during high-speed rotation, non-contact is used to prevent wear and heat generation due to friction. Bearings are suitable. The following form example meets this requirement.

<Second Embodiment> FIG. 9 is a cross-sectional view of a main portion of a second embodiment of the present invention. In this embodiment, a holding member 42 is provided on the bottom surface of the writing device cover 32. The holding member 42 of this embodiment has an inverted convex cross-sectional shape as shown in the drawing, and at the same time, the motor 19 of the motor 19 is operated during normal operation (non-rotation) shown in the drawing. It is characteristic that it is arranged with a predetermined gap between it and the output shaft 40. A gap is provided between the upper portion of the output shaft 40 of the polygon motor 19 and the lower portion of the pressing member 42 so that they do not come into contact with each other during normal operation. The value of this gap is set to such an extent that the polygon mirror 30 does not fall off the shaft 40. Therefore, when the rotating unit 20 rotates and is taken out of the machine, the polygon motor 19 is turned upside down. The polygon mirror 30 slides on the shaft 40 and stops when the output shaft 40 and the pressing member 42 come into contact with each other. That is, it does not fall off the output shaft 40. Further, when the rotating unit 20 is returned to the normal state, the polygon mirror 30 also returns to the normal position on the output shaft 40 and is seated, and the above gap between the upper portion of the output shaft 40 and the pressing member 42 is generated, resulting in a smoothness. The polygon can rotate. Therefore, even if the polygon motor 19 rotates at a high speed, friction between the pressing member 42 and the output shaft 40 does not occur, and problems due to wear, heat generation, etc. can be prevented.

<Third Embodiment> FIG. 10 shows a third embodiment of the present invention.
FIG. 9 is a cross-sectional view of an essential part of the example of the second embodiment, which is a modification of the second embodiment, in which the holding member 42 is a member different from the writing device cover 32. The form example is different in that the writing device cover 32 and the pressing member 42 are integrally configured. That is, the pressing member 42 as a convex portion is formed on the lower surface portion of the writing device cover 32 facing the upper surface of the output shaft 40 of the polygon motor, and the first pressing member 42 is provided between the top portion of the output shaft 40 and the lower surface of the pressing member 42. The same gap as in the case of the second embodiment is formed. The value of this gap is set to such an extent that the polygon mirror 30 does not fall off the shaft 40.
When 0 rotates and the polygon motor 19 reverses,
The polygon mirror 30 slides on the shaft 40 and stops when the output shaft 40 and the pressing member 42 come into contact with each other. That is, it does not fall off the output shaft 40. Further, when the rotating unit 20 is returned to the normal state, the polygon mirror 30 also returns to the normal position on the output shaft 40 and is seated, and the above gap between the upper portion of the output shaft 40 and the pressing member 42 is generated, resulting in a smoothness. The polygon can rotate. Therefore, even if the polygon motor 19 rotates at a high speed, friction between the pressing member 42 and the output shaft 40 does not occur, and problems due to wear, heat generation, etc. can be prevented. Furthermore, in this embodiment, the number of parts and the number of assembling steps can be reduced, so that the productivity can be improved and the cost can be reduced.

<Fourth Embodiment> FIG. 11 shows another embodiment of the present invention. In each of the above embodiments, the writing device cover 3 is used.
Although a rotating unit cover 33 that opens and closes the upper opening of the rotating unit 20 is provided separately from 2, the combination of the rotating unit cover (exterior cover) 33 and the writing device cover 32 is also used in this embodiment. A cover 45 is provided to close the housing 31 and the rotation unit 20, and
A characteristic feature is that a protruding pressing member 42 is provided so as to project from the bottom surface of the dual-purpose cover 45, and the lower surface of the pressing member 42 is arranged to face the top of the output shaft 40 with a predetermined gap. The function and effect of the pressing member 42 are similar to those of the third embodiment. Furthermore, in this embodiment, since only one cover component is required, cost and productivity can be increased by reducing the number of components.

<Fifth Embodiment> FIG. 12 is a cross-sectional view showing a main structure of a rotating unit according to a fifth embodiment of the present invention.
In this embodiment, the polygon motor cover 5 is provided on the inner bottom surface of the housing 31 located below the rotating unit cover 3.
0 is arranged so that the polygon motor 19 is sealed in the cover 50. In addition, a protrusion-shaped pressing member 42 is provided on the ceiling of the polygon motor cover 50, and the lower surface of the pressing member 42 is configured to face the upper portion of the output shaft 40 of the polygon motor with a predetermined gap. There is. According to this form example, similarly to the second, third and fourth form examples described above, the pressing unit 42 is not in contact with the output shaft 40 during the normal operation, but the rotating unit 20 is not contacted.
When the mirror is turned upside down, the polygon mirror 30 is slid along the shaft 40 and locked by the pressing member 42. Therefore, the polygon mirror does not fall off. Further, in this embodiment, since the polygon motor 19 is sealed in the cover 50, it is possible to prevent noise due to the polygon motor rotating at a high speed from leaking to the outside of the device. The structure of this embodiment is shown in FIG.
The present invention can be applied to the contact type of the above embodiment, and the pressing member of FIG. 9 can be applied to another member type.

<Sixth Embodiment> FIG. 13 is a cross-sectional view of an essential part of a sixth embodiment of the present invention. In this embodiment, the lower surface of the pressing member 42 of the second to fifth embodiments is rubbed. A feature is that the member 55 is integrated. That is, FIG. 13 shows, as an example, a friction member 5 which is a plate member made of a material having a large friction coefficient such as rubber or resin on the lower surface of the pressing member 42 of the embodiment example of FIG.
5 shows an example in which 5 is fixed. With this configuration, when the output shaft 40 is rotating with the polygon motor 19 being turned upside down, the top surface of the output shaft and the friction member 5 are rotated.
By making contact with 5, the rotation of the polygon mirror can be stopped early. The other effects are the same as those of the above-described embodiments.

<Seventh Embodiment> FIG. 14 is a cross-sectional view of an essential part of a seventh embodiment of the present invention. This embodiment is a modification of FIG. 13 and does not use a special friction member. , The pressing member 42
Is characterized in that the tip end surface itself is roughened or roughened to increase the friction coefficient. The effect is the sixth
Although it is similar to the above-described example, the advantage is that the number of parts can be reduced.

[0021]

According to the first aspect of the present invention, in the image forming apparatus in which the rotating unit including the image forming unit and the writing device is pivotally supported in the up and down direction with respect to the main body of the apparatus, the rotating unit is provided. When the polygon motor is reversed by rotating the shaft by 180 degrees, in a writing device having a structure in which the polygon mirror falls off the motor shaft, a pressing member is provided above the polygon motor so that the polygon mirror can be reversed even if the polygon motor is reversed. Since the − does not fall, it is possible to prevent the polygon mirror from falling and being damaged when the polygon motor reverses upside down, and when it is turned upside down like an oil dynamic pressure bearing, the polygon mirror will fall. Such a polygon motor can be applied to this image forming apparatus. According to a second aspect of the present invention, in the first aspect of the present invention, while the polygon motor is rotating, the polygon mode is set.
Since the upper part of the shaft of the motor and the pressing member are not in contact with each other, an excessive load is not applied to the polygon motor, which does not cause a failure or a shortened life.

According to a third aspect of the present invention, in the first and second aspects, since the pressing member is integrally formed with the writing device cover, when the polygon motor is turned upside down as the turning unit turns. By preventing the polygon mirror from dropping and integrating the pressing member into an existing part rather than forming it as a separate part, it is possible to manufacture at a low cost with good assembly. According to a fourth aspect of the present invention, in the invention according to the third aspect, since the writing device cover integrally formed with the pressing member also serves as an exterior cover, the polygon motor is turned upside down as the turning unit turns. By preventing the polygon mirror from falling and being damaged when it is reversed, and further, by making the pressing member an integral part with the existing part instead of being a separate part, the assembling property and the productivity are improved, and the manufacturing cost can be further reduced. it can.

According to a fifth aspect of the present invention, in the first and second aspects of the present invention, since the pressing member is integrated with the noise prevention cover of the polygon motor, the polygon motor is rotated in accordance with the rotation of the rotation unit. It is possible to further reduce the manufacturing cost by preventing the polygon mirror from falling when the work is turned upside down and by integrating the pressing member with the existing part instead of as a separate part. In other words, by integrally molding the pressing member on the cover used to prevent the noise of the polygon motor, the number of parts is reduced, the assemblability and the productivity are increased, and the cost is reduced. The noise prevention cover may be manufactured by aluminum die casting, and even if it is manufactured by resin, it is structurally stronger than the writing device cover and will not deform even if the rotating unit is pushed from above. There is no pressure on the polygon.

According to a sixth aspect of the present invention, in the invention according to the second to fifth aspects, since the friction member is provided at a portion of the pressing member that comes into contact with the polygon mirror, the polygon motor is rotated in accordance with the rotation of the rotation unit. It is possible to prevent the polygon mirror from completely falling off the motor shaft and being damaged when the vehicle is turned upside down, and the rotation of the polygon mirror is stopped by the contact between the polygon mirror and the friction member, thereby suppressing noise. That is, the rotation unit rotates and the polygon mirror shifts its position on the motor shaft to come into contact with the friction member, so that the rotation of the polygon mirror can be quickly stopped by the friction force, and the rotation of the polygon mirror does not disturb the ear. Noise can be prevented.

According to a seventh aspect of the present invention, in the invention according to the sixth aspect, since the friction member is formed integrally with the pressing member, when the polygon motor is turned upside down as the turning unit turns. Further, the polygon mirror is prevented from falling and being damaged, and the rotation of the polygon mirror is stopped by the contact between the polygon mirror and the friction member to suppress noise. That is, when the rotating unit rotates and the polygon mirror is displaced from the motor shaft, the polygon mirror comes into contact with the friction member and the rotation of the polygon mirror can be quickly stopped by the friction force, and the annoying noise due to the rotation of the polygon mirror is prevented. it can. Furthermore, by integrally forming the friction member and the pressing member, the number of parts can be reduced, the assembling efficiency can be improved, and the cost can be reduced.

[Brief description of drawings]

1A and 1B are an external perspective view and an explanatory view of a main part configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2A and FIG. 2B are operation explanatory views of a rotation unit of the image forming apparatus.

FIG. 3 is an explanatory diagram of the configuration of an example of a writing device.

FIG. 4 is a schematic configuration explanatory view of an example of a rotating unit.

5A, 5B, and 5C are operation explanatory views of an example of a rotation unit.

6A and 6B are views showing a bearing structure of a polygon motor.

FIG. 7 is a diagram showing a bearing structure of another polygon motor.

FIG. 8 is a vertical cross-sectional view showing a main part configuration of a first example of the present invention.

FIG. 9 is a vertical cross-sectional view showing the main configuration of a second embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view showing the configuration of a main part of a third example of the present invention.

FIG. 11 is a vertical cross-sectional view showing the configuration of the main parts of a fourth example of the present invention.

FIG. 12 is a vertical cross-sectional view showing the main configuration of a fifth embodiment of the present invention.

FIG. 13 is a vertical cross-sectional view showing the main configuration of a sixth embodiment of the present invention.

FIG. 14 is a vertical cross-sectional view showing the main configuration of a seventh embodiment of the present invention.

[Explanation of symbols]

1 image forming unit (image forming unit), 2 paper discharging unit, 3 sheet conveying unit, 4 paper feeding unit, 5 table unit, 6 operation display unit, 7 scanner unit, 8 upper space, 10 rotation fulcrum, A paper feeding unit Line, 13a Under fixing roller, 13b
Above fixing roller, 14a, below registration roller, 14b Above registration roller, 16 Transfer roller, 17 Cleaning roller, 18 Charging roller, 19 Polygon motor, 2
0 rotation unit, 21 writing device, 22 laser diode, 23 cylinder lens, 24 lens, 25
Mirror, 30 polygon mirror, 32 writing device cover, 33 rotating unit cover, 40 output shaft, 41
Bearing, 42 pressing member, 45 combined cover, 50 cover, 55 friction member.

Claims (7)

[Claims] 1. A rotary unit which is rotatably supported in an up-down direction with respect to an image forming apparatus main body at an end portion of a rotary unit including an image forming unit and a writing device, and which is located inside the apparatus main body. An image forming apparatus in which a polygon motor in the writing device is turned upside down when the unit is rotated and brought out of the main body of the apparatus, and an upper portion of a polygon mirror whose axis is supported by an output shaft of the polygon motor. An image forming apparatus characterized in that a pressing member is provided at the rear end of the polygon motor so that the polygon mirror does not fall off the output shaft even when the polygon motor is turned upside down. 2. The upper part of the output shaft of the polygon motor and the lower part of the pressing member are arranged so as to face each other with a predetermined gap so as not to contact each other during normal operation. Image forming device. 3. The image forming apparatus according to claim 1, wherein the pressing member has an integral structure with a writing device cover that closes an opening provided in an upper portion of a housing of the writing device. 4. The image forming apparatus according to claim 3, wherein the writing device cover integrally formed with the pressing member doubles as an exterior cover of the rotating unit. 5. The image forming apparatus according to claim 1, wherein the pressing member is integrated with a noise prevention cover that seals the polygon motor. 6. The image forming apparatus according to claim 1, wherein a friction member is provided on the pressing member portion that comes into contact with the output shaft of the polygon motor. 7. The image forming apparatus according to claim 1, wherein a friction coefficient of the pressing member portion that comes into contact with the output shaft of the polygon motor is increased.