JP2001105656A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the part cost and assembling cost increase due to increase in the number of parts required for cleaning the light exit window of a writing unit, shielding radio wave radiated from the writing unit and dustproofing the inside of the writing unit. SOLUTION: The cover of a writing unit is used for guiding a cleaning means and shielding a radio wave generating source, i.e., a circuit board. A wire bundle for supplying a drive current to the writing unit is wired through a plurality of partitioning walls.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The first and third embodiments of the present invention relate to an image forming apparatus for performing scanning exposure by deflecting a light beam emitted from a light source such as a semiconductor laser by a deflecting means. About.

[0002] The second invention relates to an image forming apparatus for performing scanning exposure by driving a semiconductor laser or a light emitting diode array by pulse driving to emit light.

[0003]

2. Description of the Related Art (1) In an image forming apparatus which performs scanning exposure by deflecting a light beam emitted from a light source such as a semiconductor laser or the like and a light beam emitted from the light source by a deflecting means, writing for performing scanning exposure is performed. In the case where a partition is provided between the apparatus and a photosensitive member to be exposed or an image forming portion for forming an image on the photosensitive member, and a window for transmitting exposure light is provided, and a cleaning means for cleaning the window is provided. There are many.
The cleaning means is configured to be guided by the guide means and to be movable along the window.

(2) In a digital image forming apparatus in which scanning exposure is performed by a light source such as a semiconductor laser or a light emitting diode array, a digital image is formed by driving the light source in a pulsed manner to emit light and exposing the photosensitive member to dot exposure. . The pulse for driving the light source is a high-frequency pulse of about several tens of MH, and a driving circuit that generates such a high-frequency pulse may generate a radio wave. Such radio waves are harmful and must be blocked in an office or the like where the image forming apparatus is installed. The manufacturer of the image forming apparatus is obliged to manufacture a product free of such harmful radio waves. For this reason, in many digital image forming apparatuses, the drive circuit is shielded with metal.

(3) The writing device which deflects a light beam by the deflecting means comprising a rotary polygon mirror to perform scanning exposure has an optical system for guiding the light beam to an exposure unit. Because it has a large-area lens or the like that passes the light beam deflected at an angle, the entire optical system is covered with a closed casing for the purpose of preventing dust from adhering to the optical system. There are many things.

[0006]

The prior art described in the above items (1) to (3) has the following problems.

(1) The provision of guide means for the cleaning means in the writing device increases the number of components, complicates the structure, and increases the component costs and assembly costs.

(2) By attaching a metal member for blocking harmful radio waves to the writing device, the number of parts is increased,
The complexity of the structure increases the cost of parts and assembly.

(3) Since the rotating polygon mirror as the deflecting means rotates at a high speed of tens of thousands of rpm, the pressure in the closed casing is reduced. As a result, dust enters the writing device from a small gap existing in the closed casing and adheres to a lens or the like, thereby deteriorating the performance of the optical system. In particular, it is necessary to provide a hole for passing a bundle for supplying a current for driving the rotary polygon mirror in the closed casing, so that dust easily enters from the hole. In order to prevent dust from entering through such a bundled wire hole, it is necessary to provide a sealing member or the like, which increases the number of components, complicates the structure, and increases component costs and assembly costs. I do.

The present invention reduces the number of parts of an image forming apparatus, particularly the number of parts constituting a writing apparatus, and simplifies the structure of the writing apparatus. And to reduce assembly costs.

[0011]

The above-mentioned object of the present invention is achieved by the following inventions.

(1) A light source for generating a light beam, a deflecting means for deflecting the light beam, a transparent plate for forming a window for transmitting the deflected light beam, a cleaning means for cleaning the transparent plate, and a cleaning means A light source, the deflecting unit, a supporting unit that supports the transparent plate, the light source, the deflecting unit, and the light source. An image forming apparatus, wherein a cover that covers a transparent plate is provided in the writing device, and at least a part of the guide unit is formed by an edge of the cover.

(2) The image forming apparatus according to (1), wherein another part of the guide means is formed at an edge of the support means.

(3) The cleaning device according to (1), wherein the cleaning means has a fiber material that contacts the transparent plate.
Or, the image forming apparatus according to the above mode (2).

(4) The image forming apparatus according to any one of (1) to (3), further including a driving unit that moves the cleaning unit along the transparent plate.

(5) A light source for generating a light beam, a driving circuit for generating a pulse for driving the light source, an optical system for guiding light from the light source to a scanning surface, and the light source, the driving circuit and the optical system An image forming apparatus including a writing device having a supporting means for supporting, wherein a cover for covering the light source, the driving circuit and the supporting means is provided, and a metal member is arranged at least in a portion of the cover covering the driving circuit. An image forming apparatus comprising:

(6) The image forming apparatus according to (5), wherein the cover is formed of a metal member.

(7) The image forming apparatus according to the above (5) or (6), wherein a pulse modulation circuit is provided at a position covered by the metal member.

(8) The image forming apparatus according to any one of (5) to (7), wherein the light source comprises a semiconductor laser.

(9) The image forming apparatus according to any one of (5) to (7), wherein the light source comprises a light emitting diode array.

(10) A writing device having a light source for generating a light beam, a deflecting means for deflecting the light beam, an optical system for guiding the light beam to a scanning surface, and a casing for covering the light source, the deflecting means and the optical system. In an image forming apparatus provided with a device, a bundle of wires for supplying a drive current to the deflecting unit is wired through a hole provided in the casing, and a plurality of partition walls having holes for wiring the bundle of wires in the casing are formed. An image forming apparatus, comprising:

(11) The image forming apparatus according to (10), wherein the partition wall, together with the bottom plate portion and the cover portion of the casing, forms a closed room except for the holes.

(12) The hole (10) or (11), wherein the holes are formed so as to be shifted from each other for each of the partition walls so that the bundles are wired in a meandering manner. An image forming apparatus according to claim 1.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Image forming apparatus (first to third embodiments)
Embodiments Common to the Present Invention) An image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a digital image forming apparatus (hereinafter, referred to as a digital image forming apparatus).
FIG. 1 is a diagram illustrating a configuration of an image forming apparatus 1.

Referring to FIG. 1, an image forming apparatus 1 includes an automatic document feeder (ADF) A, a document image reading unit B for reading an image of a document fed by the automatic document feeder, and a read document image. Image control board C to be processed
A writing device D on a drum-shaped photoreceptor 10 as an image carrier according to data after image processing, a charging electrode 14 around the photoreceptor 10 and a developing means 16 including a magnetic brush type developing device; An image forming section E including image forming means such as an electrode 18, a separation electrode 20, and a cleaning means 21;
It has a storage section F for paper feed trays 22 and 24 for storing recording paper P.

The automatic document feeder A includes a document table 26
And a document transport processing unit 28 including a roller group including a roller R1 and switching means for appropriately switching a document movement path (no reference symbol).

The original image reading section B is located under the platen glass G, and can move back and forth while maintaining the optical path length, a fixed image forming lens (hereinafter simply referred to as a lens) 33, and a line-shaped image forming section. Image sensor (hereinafter referred to as CCD
The writing device D includes a semiconductor laser 103 as a light source and a rotating polygon mirror 10 as a deflecting unit.
6 mag.

When viewed from the moving direction of the recording paper P as a transfer material, R10 shown on the front side of the transfer electrode 18 is a registration roller, and H shown on the downstream side of the separation electrode 20 is a fixing means.

In the embodiment, the fixing means H comprises a roller having a built-in heating source and a pressure roller which rotates while being pressed against the roller.

Z is a cleaning means for the fixing means H, and has a cleaning web provided so as to be wound up as a main element.

One of the originals (not shown) placed on the original placing table 26 is transported by the original transport processor 28,
While passing under the roller R1, exposure by the exposure means L is performed.

The reflected light from the original passes through the mirror units 30 and 31 and the lens 33 at the fixed position and passes through the CCD 3.
5 and is read.

The image information read by the document image reading section B is processed by the image processing means, encoded and stored in a memory provided on the image control board C.

Further, the image data is called in accordance with the image formation, and the laser light source 40 in the writing device D is driven according to the image data, so that the photosensitive member 10 is exposed.

Prior to the exposure, the photoreceptor 10 rotating in the direction of the arrow (counterclockwise) is given a predetermined surface potential by the corona discharge action of the charging electrode 14. As a result, the electrostatic latent image is formed on the photoconductor 10 according to the image data.

The electrostatic latent image is reversely developed by the developing means 16 to be a visible image (toner image).

On the other hand, before the leading end of the toner image on the carrier 10 reaches the transfer area, for example, one recording sheet P in the sheet feed tray 22 is fed and conveyed to the registration roller R10.
And is regulated at the tip.

The recording paper P is conveyed toward a transfer area by a registration roller R10 that starts rotating in synchronization with the toner image, that is, the image area on the photoconductor 10, so as to overlap.

In the transfer area, the toner image on the photosensitive member 10 is transferred onto the recording paper P by the bias of the transfer electrode 18,
Next, the recording paper P is separated from the photoconductor 10 by the bias of the separation electrode 20.

Thereafter, the fixing unit H is pressurized and heated to
The toner powder forming the toner image is melted and fixed on the recording paper P, and the recording paper P is discharged onto the discharge tray T via the discharge path 78 and the discharge roller 79.

In the embodiment, the paper feed trays 22 and 24 are arranged in two stages in the vertical direction. However, a larger number of paper feed trays may be provided.

The bottom portion (the same as the bottom wall) of the sheet feeding tray 24 arranged at the lower stage (in the embodiment, the sheet feeding tray is a lower stage because the sheet feeding tray is a two-stage stack, but it is the lowermost stage). A space 25 having a predetermined gap is formed between the apparatus and the bottom wall of the apparatus main body.

The space 25 is used in a mode (mode) for forming an image on both sides of the recording paper P, and cooperates with a second transport path 80 (described later) for reversing the recording paper P. To achieve the reverse of the front and back.

Reference numerals 50 and 53 above the respective leading ends (corresponding to the leading ends of the stored recording sheets P as viewed from the sheet feeding direction) of the sheet feeding trays 22 and 24 denote sheet feeding means (hereinafter referred to as feed-out means) comprising rollers. Rollers), 51 and 54
Is a feed roller, and 52 and 55 are double feed prevention rollers.

The feed rollers (50, 53) and the feed rollers (51, 54) are formed as a unit, and a drive shaft connected to a drive source provided on the apparatus main body side or a locking means provided on a paper feed unit. It has a configuration that can be easily attached to and detached from.

The double feed prevention rollers (52, 55) are also unitized, and have a structure that can be easily attached to and detached from a fixing member provided on a fixing portion of the apparatus main body.

Reference numeral 60 denotes a manual paper feed tray of the manual paper feed unit, which can be opened and closed with the lower end serving as a fulcrum with respect to the main body side wall of the image forming apparatus 1.

Reference numeral 61 denotes a feed roller formed of a roller for sending the recording paper placed on the manual feed tray 60 with the image formation, 63 denotes a feed roller provided downstream of the feed roller 61, and 65 denotes a feed roller. Roller 6
3, a double feed prevention roller for preventing a plurality of sheets of recording paper P from being fed, and has substantially the same configuration as that of the above-described paper feed trays 22 and 24.

Reference numeral 66 denotes a conveyance path for the recording paper P sent out from the manual feed tray 60, which communicates with a later-described junction through a pair of conveyance rollers shown immediately to the left of the feed roller 63.

Reference numeral 70 denotes a first conveyance path for forming an image on the recording paper P by transfer, and extends upward from below when viewed from the moving direction of the recording paper sent from an appropriate paper feed tray. .

Reference numeral 72 denotes a paper feed path for recording paper stored in the upper paper feed tray 22, reference numeral 74 denotes a paper feed path for recording paper stored in the lower paper feed tray 24, and reference numeral 76 denotes both trays 2.
It is a merging portion (a part of the first conveyance path 70) where the recording papers P sent from 2 and 24 merge.

Reference numeral 78 denotes a paper discharge path for discharging the recording paper on which a predetermined image has been formed onto the paper discharge tray T.

Numeral 80 denotes a second transport path for reversing the recording paper used for forming an image on both sides of the recording paper.
The upper part of the figure communicates with the first transport path.

The second transport path 80 extends downward from above when viewed from the direction of movement of the recording paper.

The lower end of the second conveying path 80 is a conveying path extending substantially vertically, and the lower end extends below the sheet feeding section of the lower sheet feeding tray 24.
0 (connected).

As understood from the above, the first transport path 7
0 and the second transport path 80 form a long loop in the longitudinal direction on one side wall side of the apparatus main body.

At the connection between the first transport path 70 and the second transport path 80, a transport means R20 comprising a pair of reversible rollers is provided.

Since the recording paper P is not continuously conveyed from the second conveyance path 80 to the first conveyance path 70, the connection part can be said to be a branch part for dividing the two conveyance paths.

Below the switchback roller R20, there is provided a passage leading to the space 25, and when the recording paper P is turned upside down, the recording paper P moving through the second transport path 80 is passed through the space 25. Used to go to.

In the image forming process, the second transport path 8
When the recording paper P moving through the recording paper P is sent out toward the space 25, the rear end of the recording paper P is configured to be gripped by the switchback roller R20. 25 stores a part of the recording paper.

Reference numeral 90 denotes an (upper) branch guide which directs the recording paper P, on which an image has been formed on the first surface, to the paper discharge passage 78,
Alternatively, it is controlled so as to be directed to the second transport path 80.

In other words, the image forming apparatus is controlled according to a user-set image forming mode (a mode in which an image is formed on only one side of recording paper or a mode in which an image is formed on both sides of recording paper).
It can be said that the recording paper transport path is switched.

For example, when the mode for forming an image on both sides of the recording paper is set, the branch guide 90 carries the second conveyance of the recording paper P on which the image is formed on the first side and which has the transfer toner image. After the recording paper is fed to the second conveyance path 80, the sheet is controlled via a control unit (not shown) so as to take the solid line position in the figure.

The first transport path 70 and the second transport path 8
A member that is located on 0 and indicated by a pair of circles (no reference symbol)
Is a transport roller.

The image forming process for the second side of the recording paper in the image forming apparatus having the above configuration is as follows.

As described above, when the recording paper P on which the image has been formed on the first surface moves up the first transport path 70 and the leading end reaches the branch guide 90, the branch guide 90 is moved to the position indicated by the broken line in FIG. The recording paper P is kept in the second transport path 80
And continue to move.

The entrance portion of the second transport path 80 has a gentle arc, and ensures smooth movement of the recording paper P.

When the recording paper P descends on the second conveyance path 80 and reaches the lower end thereof, the recording paper P is nipped by the switchback roller R20 and conveyed downward from the second conveyance path to the lower sheet feeding tray 24. It is led to the space 25 formed below.

At this time, the first image formed on the recording paper P
The surface is facing down.

Eventually, when the rotation of the switchback roller R20 is stopped in a state where the rear end of the recording paper P is nipped, and then the rotation is started in the reverse direction, the recording paper P is turned upside down, that is, Then, the sheet is fed into the first conveyance path 70 in a state where the second surface on which the image is not formed is directed to the photoconductor 10 side, and is regulated by the registration roller R10.

On the other hand, a second toner image is formed on the photoconductor 10 by the above-described process. When the registration roller R10 starts rotating in synchronization with the rotation of the photoconductor 10, the second toner image is formed. The recording paper P enters the transfer area while overlapping the image area.

Thereafter, when the leading end of the recording paper P subjected to the transfer processing, the separation processing, and the fixing processing reaches a certain portion of the branch guide 90, the branch guide 90 is kept at the position indicated by the solid line in FIG. Since the first transport path 70 and the paper discharge path 78 are in communication with each other and the communication with the second transport path 80 is cut off, the recording paper P enters the paper discharge path 78 and passes through the paper discharge rollers 79. The paper is discharged onto the paper discharge tray T.

(2) Writing Apparatus (Embodiment Common to First to Third Embodiments) A writing apparatus D of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.

The outer shape of the writing device D is formed by a support frame 100 as support means and a cover 120 made of a single metal plate. The support frame 100 is a resin-made plate-shaped frame composed of a bottom plate portion 101 on which a number of ribs are formed and a surrounding side wall 102. The cover 120 is in close contact with the side wall 102, and the support frame 100 and the cover 120 form a casing that seals the inside.

A semiconductor laser 103 as a light source for emitting a light beam, a collimator lens 10
4. First cylindrical lens 105, rotating polygon mirror 106 as a deflecting means for deflecting the light beam to a wide angle, fθ
A lens 107, a second cylindrical lens 108, a transparent plate 109 forming an emission window, an index sensor mirror 110, and an index sensor 111 are attached.

The light beam emitted from the semiconductor laser 103 enters the scanning surface of the photosensitive member 10 of FIG. 1 as dots by the collimator lens 104, the first cylindrical lens 105, the fθ lens 107, and the second cylindrical lens 108, and rotates. The scanning plane is scanned and exposed by the rotation of the polygon mirror 106.

(3) Cleaning of the transparent plate 109 (first
Embodiment of the Invention) The cleaning of the transparent plate 109 will be described with reference to FIGS.

The transparent plate 109 is made of transparent glass and transmits a light beam. As shown in FIGS. 3 and 4, the transparent plate 109 is fitted into the side wall 102 of the support frame 100, and is formed of an elongated transparent glass plate having substantially the same length as the second cylindrical lens 108.

The cleaning means for cleaning the outer surface of the transparent plate 109 is composed of a resin support block 130 and a fiber material 136 such as felt attached to the support block. The support block 130 includes guide pieces 131, 1
32 and 133, the engagement portion 134, and the fiber material support portion 135
have. The guide pieces 131 and 132 are
1 as a guide means formed by bending
21 is sandwiched from both sides. The guide piece 132 is formed on a guide rail 119 serving as a guide means formed on the side wall 102.
Is engaged. The fiber material 136 is bonded and fixed to the fiber material support 135 so as to cover the fiber material support 135.

The operating rod 140 as a driving means for reciprocating the cleaning means as shown by the arrow W is composed of a handle 141 and an engaging rod 142 which fits into a hole of the engaging portion 134. The engagement rod 142 is supported and guided by an engagement arm 143 provided on the support frame 100.

By operating the handle 141 to reciprocate the cleaning means from one end of the transparent plate 109 to the other end in the direction of arrow W, the fiber member 136 cleans the outer surface of the transparent plate 109. You. And
The cleaning means is guided by the bent portion 121 and the guide rail 119 and uniformly contacts the transparent plate 109 to perform uniform cleaning.

The first invention is applied to various types of writing devices for performing writing by deflecting a light beam such as a laser by a deflecting means such as a rotary polygon mirror in addition to the above-described embodiments. can do.

(4) Shielding of Radio Waves (Second Embodiment of the Invention) The shielding of radio waves radiated from the writing device D will be described with reference to FIG. Circuit board 14 on which a drive circuit for generating a pulse for driving semiconductor laser 103 as a light source is formed
4 is provided near the semiconductor laser 103. A portion 122 of the cover 120 made of a metal such as a single metal plate, for example, aluminum or steel, which is surrounded by oblique lines in FIG. 2, covers a portion where the circuit board 144 is provided. When a radio wave is radiated from the writer D, the radio wave is blocked to prevent the radio wave from being radiated outside the writing device D.

The cover may be made of resin. When a cover made of resin is used, it is necessary to provide a metal layer at least on a portion 122 covering the circuit board 144 to block radio waves. It is.

The second invention can be applied to various types of writing devices that emit light by pulse driving a laser, a light emitting diode array (LED array), etc., in addition to the above-described embodiments. it can. Note that a pulse modulation circuit such as a PWM circuit can be provided on the circuit board 144 in addition to the driving circuit.

(5) Prevention of Ingress of Dust (Third Embodiment of the Invention) Dust prevention inside the writing device D will be described with reference to FIGS.

The rotating polygon mirror 106 rotates at a high speed of tens of thousands of rpm by using a well-known electromagnetic drive mechanism when writing an image. A connector 116 is provided on a support substrate 115 for supporting a drive coil (not shown) for driving the rotary polygon mirror 106 and the like. One end of a bundled wire 118 for supplying a current to the drive coil is connected to the connector 116. The other end of the bundle 118 is connected to a connector 117 fixed to the side wall 102. As shown in FIG. 5, the bundled wires 118 are wired through holes 112a, 113a, 114a provided in three ribs 112, 113, 114 as partition walls provided in the bottom plate portion 101, respectively. The holes 112a, 113a, and 114a are shown in FIG.
FIG. 5B is a cross-sectional view taken along line NN in FIG.
As shown in (1), the bundled wires 118 are provided so as to be displaced from each other so that they are not straight but bent. Moreover, the rib 11
As shown in FIG. 5B, 2, 113 and 114 are formed such that their tips are in close contact with the cover 120 and hermetically partition the room between the ribs.

Although the inside of the writing device D is sealed by a casing formed by the support frame 100 and the cover 120, when the rotary polygon mirror 106 rotates at a high speed, the pressure inside the writing device D is reduced, and dust enters from the outside. It will be easier. In particular, since a small gap is formed in the portion of the connector 117, dust easily enters therethrough. As described above, the inside of the writing device D is partitioned by the plurality of ribs 112, 113, and 114, so that entry of dust from the wiring portion of the bundled wire 118 is effectively provided. In particular, holes 112a, 113a, 114a
Is shifted to meander the wiring 118 to effectively prevent dust from entering the optical system or the like inside the writing device D. In addition, it is possible to prevent dust from entering without providing a sealing member or the like for dust prevention.

[0090]

According to the first aspect of the present invention, the guide means for the cleaning means for cleaning the transparent plate for emitting the light beam from the writing device is formed by the cover of the writing device. In addition to the reduction, the structure of the writing device is simplified. As a result, component costs and assembly costs of the image forming apparatus are reduced.

According to the second aspect of the present invention, the guide of the cleaning means is reliably performed, and the cleaning of the transparent plate is effectively performed.

According to the third aspect of the present invention, the cleaning of the transparent plate is performed very effectively.

According to the fourth aspect of the present invention, the operation of cleaning the transparent plate is facilitated.

According to the fifth or sixth aspect of the present invention, the radio wave is cut off from the drive circuit for driving the light source in a pulsed manner by the cover. Costs and assembly costs are reduced.

According to the seventh aspect of the present invention, the circuit portion for driving the light source is collectively arranged in the writing device, and the unitization of the writing device is further promoted.

According to the eighth aspect of the present invention, radio waves are effectively cut off when a semiconductor laser is used as a light source.

According to the ninth aspect of the present invention, the radio wave is effectively cut off when the light emitting diode array is used as the light source.

According to the tenth aspect, it is possible to effectively prevent dust from entering the inside of the writing apparatus without increasing the number of parts, and to reduce parts costs and assembly costs of the image forming apparatus.

According to the eleventh aspect, dust protection inside the writing device is extremely effectively performed.

According to the twelfth aspect of the present invention, dust inside the writing device can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a writing device in the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing an emission window of the writing device.

FIG. 4 is a sectional view taken along line MM in FIG. 3;

FIG. 5 is a diagram showing a wiring portion of a bundled wire for a rotary polygon mirror in the writing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Support frame 103 Semiconductor laser 104 Collimator lens 105 First cylindrical lens 106 Rotating polygon mirror 107 fθ lens 108 Second cylindrical lens 109 Transparent plate 112, 113, 114 Rib 112a, 113a, 114a Hole 118 Bundle wire 119 Guide rail 120 Cover 121 Folding part 130 Support block 131, 132, 133 Guide piece 136 Fiber material 144 Circuit board D Writing device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C362 AA03 DA09 DA14 DA41 EA11 EA16 2H045 AA01 BA23 DA02 DA04 2H076 AB05 AB58 AB82 EA18

Claims (12)

[Claims] A light source for generating a light beam; a deflecting means for deflecting the light beam; a transparent plate forming a window for transmitting the deflected light beam; a cleaning means for cleaning the transparent plate; An image forming apparatus comprising: a writing device having a guide unit movably guided along a transparent plate, wherein the light source, the deflecting unit, a supporting unit that supports the transparent plate, the light source, the deflecting unit, and the transparent unit. An image forming apparatus, wherein a cover for covering a plate is provided in the writing device, and at least a part of the guide means is formed by an edge of the cover. 2. The image forming apparatus according to claim 1, wherein another part of said guide means is formed at an edge of said support means. 3. The image forming apparatus according to claim 1, wherein the cleaning unit includes a fiber material that contacts the transparent plate. 4. The image forming apparatus according to claim 1, further comprising a driving unit that moves the cleaning unit along the transparent plate. 5. A light source for generating a light beam, a driving circuit for generating a pulse for driving the light source, an optical system for guiding light from the light source to a scanning surface, and supporting the light source, the driving circuit and the optical system An image forming apparatus comprising a writing device having: a cover that covers the light source, the drive circuit, and the support unit; and a metal member disposed at least on a portion of the cover that covers the drive circuit. Characteristic image forming apparatus. 6. The image forming apparatus according to claim 5, wherein the cover is made of a metal member. 7. A pulse modulation circuit is provided at a position covered by the metal member.
An image forming apparatus according to claim 1. 8. The image forming apparatus according to claim 5, wherein said light source comprises a semiconductor laser. 9. The image forming apparatus according to claim 5, wherein said light source comprises a light emitting diode array. 10. A writing apparatus having a light source for generating a light beam, a deflecting means for deflecting the light beam, an optical system for guiding the light beam to a scanning surface, and a casing for covering the light source, the deflecting means and the optical system. An image forming apparatus comprising: a plurality of partition walls having holes for wiring the bundled wires provided in the casing, wherein bundled wires for supplying a drive current to the deflecting unit are wired through holes provided in the casing; An image forming apparatus characterized in that: 11. The image forming apparatus according to claim 10, wherein the partition wall, together with a bottom plate portion and a cover portion of the casing, forms a closed room except for the holes. 12. The method according to claim 10, wherein the holes are formed so as to be shifted from each other for each of the partition walls so that the bundled wires are wired in a meandering manner. Image forming device.