Image forming apparatus including a photosensitive drum and exposing member movable between an exposure position close to the drum and an evacuation position evacuated from the drum

An image forming apparatus includes: a main apparatus body; an opening/closing member; a drum unit including a photosensitive drum and can be pulled out of an accommodating space along an axial direction of the photosensitive drum; an exposing member provided in the main apparatus body and movable between an exposure position and an evacuation position; and a movable mechanism including: a first movable member movable in accordance with an opening/closing operation of the opening/closing member; and a second movable member for moving the exposing member between the exposure position and the evacuation position in accordance with movement of the first movable member. The second movable member supports both end portions of the exposing member. The second movable member moves the exposing member to the exposure position or the evacuation position by the movement of the first movable member in accordance with the movement of the opening/closing member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No. 2011-284468 filed on Dec. 26, 2011, the entire subject matter of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image forming apparatus using an electrophotographic method.

BACKGROUND

As an example of electrophotographic image forming apparatuses, there have been known an image forming apparatus including a main apparatus body, a photosensitive drum, a processing cartridge mountable to and removable from the main apparatus body along the axial direction of the photosensitive drum, and an LED array head for exposing the photosensitive drums. In this image forming apparatus, when the processing cartridge is mounted to or removed from the main apparatus body, it is necessary to prevent interference between the processing cartridge and the LED array head. To this end, various configurations for evacuating the LED array heads have been considered.

For example, there have been proposed an image forming apparatus including a holding member that holds LED array heads and is movable in a vertical direction, and a bracket that is disposed to be adjacent to the holding member in the axial direction of photosensitive drums and is linearly movable in a direction perpendicular to both of the axial direction of the photosensitive drums and the vertical direction. In this related-art image forming apparatus, pins protruding along the axial direction of the photosensitive drums are provided at the holding member, and guide holes having tapered portions inclined diagonally upward are formed at the bracket.

In this related-art image forming apparatus, in accordance with linear movement of the bracket, the pins of the holding member are guided along the inclination of the tapered portions of the bracket, and the holding member is moved to advance or evacuate such that the LED array heads are moved between first positions where the LED array heads are close to the photosensitive drums and second positions where the LED array heads are evacuated from the photosensitive drums.

SUMMARY

However, in the above-described related-art image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2001-175046, in accordance with the linear movement of the bracket, the pins of the holding member are guided by the tapered portions of the bracket, whereby the LED array heads are moved between the first positions and the second positions. To this end, it is necessary to secure a linear movement distance for the bracket corresponding to the amount of displacement of the LED array heads. Since it is necessary to secure the linear movement distance, it is difficult to reduce a size the image forming apparatus.

Therefore, illustrative aspects of the present invention provide an image forming apparatus capable of securing certain movement of exposing members with reducing a size of the apparatus.

According to one illustrative aspect of the present invention, there is provided an image forming apparatus comprising: a main apparatus body having an accommodating space partitioned therein and an opening configured to connect the accommodating space and an outside; an opening/closing member provided at the main apparatus body and configured to move between an open position for opening the opening and a closed position for closing the opening; a drum unit comprising a photosensitive drum configured to carry a developer image and accommodated in the accommodating space, wherein the drum unit is configured to be pulled out of the accommodating space along an axial direction of the photosensitive drum; an exposing member provided in the main apparatus body and configured to move between an exposure position, which is close to the photosensitive drum for exposing the photosensitive drum, and an evacuation position where the exposing member evacuates from the photosensitive drum; and a movable mechanism. The movable mechanism comprises: a first movable member configured to move in accordance with an opening/closing operation of the opening/closing member; and a second movable member configured to move the exposing member between the exposure position and the evacuation position in accordance with movement of the first movable member. The second movable member is configured to support both end portions of the exposing member. The second movable member is configured to move the exposing member from the exposure position to the evacuation position by the movement of the first movable member in accordance with the movement of the opening/closing member from the closed position to the open position. The second movable member is configured to move the exposing member from the evacuation position to the exposure position by the movement of the first movable member in accordance with the movement of the opening/closing member from the open position to the closed position.

DETAIL DESCRIPTION

1. Overall Configuration of Printer

As shown inFIGS. 1 and 2, a printer1(one example of an image forming apparatus) is an intermediate transfer type color printer.

The printer1is a multi-function apparatus integrally includes a main body casing2(one example of a main apparatus body) and a flatbed scanner3configured to read image information of a document.

(1) Main Body Casing

The main body casing2is formed in a substantially box shape. At one side wall of the main body casing2, a main opening4(one example of an opening) is formed. The main body casing2is provided such that a front cover5(one example of an opening/closing member) for opening and closing the main opening4is swingable (e.g., movable) between a closed position (seeFIG. 2) for closing the main opening4and an open position (seeFIGS. 5A and 5B) for opening the main opening4around an lower end portion thereof.

In the following description, the front cover (5) side (e.g., the left side on the drawing paper ofFIG. 2) is the front side of the printer1, and the opposite side (e.g., the right side on the drawing paper ofFIG. 2) to the front cover (5) side is the rear side of the printer1. The left and right sides of the drawings refer to the left and right sides of the printer1as seen from a user facing the printer1.

That is, inFIG. 1, the left side of the drawing paper is the left side of the printer, and the right side of the drawing paper is the right side of the printer. Further, a direction from the drawing paper toward a viewer is the front side of the printer, and a direction from the drawing paper toward the opposite side to the viewer side is the rear side of the printer.

The main body casing2includes a sheet feeding unit6for feeding sheet P, an image forming unit7for forming an image on the fed sheet P, and a discharging unit8for discharging the sheet P having an image formed thereon.

(2) Sheet Feeding Unit

The sheet feeding unit6is provided at the bottom of the main body casing2. The sheet feeding unit6includes a sheet feed tray9which is for accommodating sheets P (seeFIG. 5A) and is mountable and removable.

Sheets P in the sheet feed tray9are conveyed by various rollers one at a time. The sheet P is fed into the image forming unit7(between an intermediate transfer belt24(to be described below) and a secondary transfer roller21(to be described below)) at a predetermined timing.

(3) Image Forming Unit

The image forming unit7is disposed on the sheet feeding unit6. The image forming unit7includes a drum unit10, a plurality of (e.g., four) developing units11, a plurality of (e.g., four) LED units12, a transfer unit13, and a fixing unit14.

(3-1) Drum Unit

The drum unit10is mounted to the main body casing2and is configured to be pulled out along the front/rear direction.

The drum unit10includes a pair of drum frames32, photosensitive drums15, and scorotron chargers16.

The paired drum frames32are formed in substantially flat plate shapes extending in the left/right direction and face each other with a gap in the front/rear direction.

At the lower portions of the drum frames32, mount/removal grooves46are formed corresponding to the plurality of developing units11.

The drum frames32are projected in the front/rear direction, and portions of the drum frames32overlapping the upper end portions of the developing units11during the projection are cut off, whereby the mount/removal grooves46are formed,

A plurality of (e.g., four) photosensitive drums15are provided corresponding to multiple colors (e.g., black, yellow, magenta, and cyan), and are arranged in parallel with intervals in the left/right direction.

The photosensitive drums15are formed in substantially cylindrical shapes extending in the front/rear direction (e.g., axial direction), and the front and rear end portions of the photosensitive drums15are supported to by the pair of drum frames32, such that the photosensitive drums15are rotatable.

The scorotron chargers16are provided corresponding to the plurality of photosensitive drums15, and are supported by the drum frames32such that the scorotron chargers16face the photosensitive drums15from the right sides of the photosensitive drums15with gaps.

(3-2) Developing Unit

Each of the plurality of developing units11is disposed to face the lower la side of a corresponding photosensitive drum15. Each of the developing units11includes a corresponding developing roller17.

The developing rollers17are supported at the upper ends of the developing units11such that the developing rollers17are rotatable and are exposed from their upper sides, and are in contact with corresponding photosensitive drums15of the drum unit10from their lower left sides.

Incidentally, the developing units11include feed rollers18for feeding toner to the developing rollers17, and layer-thickness regulating blades19for regulating the thicknesses of fed toner on the developing rollers17. In the developing units11, toner (one example of developer) is accommodated in the lower sides of the feed rollers18.

From among the plurality of developing units11, the leftmost developing unit11includes a waste-toner accommodating unit44for accommodating toner (waste toner) remaining on the surface of the intermediate transfer belt24(to be described be low).

(3-3) LED Unit

Each of the plurality of LED units12is disposed on the lower side of a corresponding photosensitive drum15such that a corresponding LED unit12faces the corresponding photosensitive drum15in the vertical direction. The LED units12expose the surfaces of the corresponding photosensitive drums15on the basis of predetermined image data.

(3-4) Transfer Unit

The transfer unit13includes a belt unit20and a secondary transfer roller21.

The belt unit20is disposed along the left/right direction such that the belt unit20faces all of the photosensitive drums15from the upper sides of the photosensitive drums15.

The belt unit20includes a drive roller22, a driven roller23, the intermediate transfer belt24, and a plurality of (e.g., four) primary transfer rollers25, and a belt cleaner37.

The drive roller22and the driven roller23are disposed to face each other in the left/right direction with a gap therebetween.

The intermediate transfer belt24is wound around the drive roller22and the driven roller23such that the lower portion of the intermediate transfer belt24comes into contact with all of the photosensitive drums15. The intermediate transfer belt24goes around in accordance with the driving of the drive roller22and the following of the driven roller23such that the lower portion of the intermediate transfer belt21moves from the left side to the right side.

Each of the primary transfer rollers25is disposed to face a corresponding photosensitive drum15with the lower portion of the intermediate transfer belt24interposed therebetween.

The belt cleaner37is provided on the upper side of the left end portion of the intermediate transfer belt24. The belt cleaner37includes a belt cleaning roller38, a facing roller39, a relay roller40, a scraping blade41, and a waste-toner retaining unit42.

Toner remaining on the surface of the intermediate transfer belt24(e.g., waste toner) is held by the belt cleaning roller38, is held by the relay roller40, is scraped by the scraping blade41, and is retained in the waste-toner retaining unit42. The waste-toner retaining unit42is connected to the waste-toner accommodating unit44through a conveyance pipe43. The waste toner retained in the waste-toner retaining unit42is transferred into the waste-toner accommodating unit44through the conveyance pipe43.

The secondary transfer roller21is provided on the right side of the belt unit20such that the secondary transfer roller21faces the drive roller22of the belt unit20with the intermediate transfer belt24interposed therebetween.

(3-5) Fixing Unit

The fixing unit14is disposed on the upper side relative to the secondary transfer roller21. The fixing unit14includes a heating roller26, and a pressing roller27facing the heating roller26.

(3-6) image Forming Operation

(3-6-1) Developing Operation

Toner in the developing units11is fed onto the feed rollers18, and then is fed onto the developing rollers17.

The rotation of the developing rollers17causes friction between the developing rollers17and the feed rollers18, which charges the fed toner on the developing rollers17to have positive polarity. The positively charged toner on the developing rollers17is regulated by the layer-thickness regulating blades19such that the toner is carried as thin layers of a constant thickness on the surfaces of the developing rollers17.

In accordance with the rotation of the photosensitive drums15, the surfaces of the photosensitive drums15are uniformly and positively charged by the scorotron chargers16, and are exposed by the LED units12. Therefore, electrostatic latent images corresponding to an image to be formed on a sheet P are formed on the surfaces of the photosensitive drums15.

When the photosensitive drums15further rotate, the toner carried on the surfaces of the developing rollers17is fed onto the electrostatic latent images of the photosensitive drums15. Therefore, on the surfaces of the photosensitive drums15, toner images based on reversal development are carried.

(3-6-2) Transferring and Fixing Operations

The toner images carried on the surfaces of the photosensitive drums15are primarily transferred onto the lower portion of the intermediate transfer belt24moving from the left side to the right side.

The transferred toner images on the intermediate transfer belt24are secondarily transferred onto a sheet P fed from the sheet feeding unit6while the sheet P passes a position where the intermediate transfer belt24faces the secondary transfer roller21.

Then, while the sheet P passes between the heating roller26and the pressing roller27, the transferred toner image on the sheet P is thermally fixed to the sheet P by heat and a pressure in the fixing unit14.

At the top of the main body casing2, a discharge tray28onto which sheets P are discharged is formed. The discharging unit8is formed at the upper right end portion of the main body casing2such that the discharging unit8protrudes toward the upper side relative to the discharge tray28.

At the upper portion of the discharging unit8relative to the discharge tray28, a discharging port29for discharging sheets P is formed. The discharging unit8includes a plurality of (e.g., three) discharging rollers30, which is provided inside the discharging port29and is for discharging sheets P onto the discharge tray28.

The sheet P having the toner image fixed thereon in the fixing unit14is discharged onto the discharge tray28by the discharging rollers30.

The flatbed scanner3is supported with a gap from the upper side of the discharge tray28by the upper end portion of the discharging unit8.

2. Main Body Casing

As shown inFIG. 2, the main body casing2includes an outer casing33forming the appearance of the printer1, and an inner casing34provided on the internal side of the outer casing33.

The outer casing33is formed in a substantially box shape which is substantially rectangular in a side view. The front cover5is provided at the front end portion of the outer casing33.

The inner casing34is formed in a substantially box shape which is substantially rectangular in a side view. The inner casing34has a length in the vertical direction and a length in the left/right direction such that the inner casing34can accommodate the sheet feeding unit6(seeFIG. 1) and the image forming unit7. The inner casing34is accommodated in the outer casing33with a gap from the outer casing33on the rear side.

Inside the inner casing34, a drum-unit accommodating part36(one example of an accommodating space) is partitioned for accommodating the drum unit10.

As shown inFIG. 1the drum-unit accommodating part36is formed below the belt unit20and has a substantially rectangular shape capable of accommodating the drum unit10as seen in a side view.

Further, as shown inFIG. 2, an LED supporting frame35for supporting the LED units12is provided inside the inner casing34.

The LED supporting frame35is formed in a substantially flat plate shape and is provided above the sheet feed tray9so as to partition the internal space of the inner casing34.

The LED supporting frame35is provided with main-body-side guide parts99and main-body-side fitting parts100.

As shown inFIG. 3, the main-body-side guide parts99include two front main-body-side guide parts99and two rear main-body-side guide parts99. The front main-body-side guide parts99are provided at the front portion of the LED supporting frame35(seeFIG. 2) such that the front main-body-side guide parts99face each other in the left/right direction with a gap. The rear main-body-side guide parts99are provided at the rear portion of the LED supporting frame35(seeFIG. 2) such that the rear main-body-side guide parts99face each other in the left/right direction with a gap.

Specifically, the front main-body-side guide parts99are provided corresponding to first guide bosses76(to be described below) of a slide member61(one example of a first movable member) (to be described below), and the rear main-body-side glide parts99are provided corresponding to second guide bosses80(to be described below) of the slide member61(to be described below). Further, the front main-body-side guide parts99are aligned with the rear main-body-side guide parts99in the front/rear direction.

The main-body-side guide parts99are formed in a substantially U shape extending in the front/rear direction as seen in a side vide, and free end portions of the main-body-side guide parts99are fixed to the top of he LED supporting frame35.

The inner sides of the main-body-side guide parts99are formed such that lengths in the front/rear direction are about three times the outside diameter of each first guide boss76(second guide boss80) (to be described below), and lengths in the vertical direction is substantially the same as the outside diameter of each first guide boss76(the second guide boss80) (to be described below).

As shown inFIG. 5B, a compression spring101(one example of a pressing member) and a covering part102are provided inside the front main-body-side guide part99corresponding to the first guide boss76(to be described below).

The covering parts102are formed in a substantially cylindrical shape extending in the front/rear direction, and the front end portions of the covering parts102are closed. The covering parts102are disposed to accommodate the front portions of the compression springs101therein.

The compression springs101are formed in an air-core coil shape extending in the front/rear direction. The rear end portions of the compression springs101are fixed to the rear end portions of the main-body-side guide parts99, and the front end portions of the compression springs101are fixed to the rear surfaces of the front walls of the covering parts102. Incidentally, other compression springs101and the covering parts102may be provided in the rear main-body-side guide parts99corresponding to the second guide bosses80(to be described below).

As shown inFIG. 3, the main-body-side fitting parts100include two front main-body-side fitting parts100and two rear main-body-side fitting parts100. The front main-body-side fitting parts100are provided on the rear side relative to the two front main-body-side guide parts99, such that the front main-body-side fitting parts100face each other in the left/right direction with a gap. The rear main-body-side fitting parts100are provided on the rear side relative to the two rear main-body-side guide parts99, such that the rear main-body-side fitting parts100face each other in the left/right direction with a gap.

Specifically, the front main-body-side fitting parts100are provided corresponding to rear side first fitting portions86to be described below) of a front movable member62F (to be described below), and the rear main-body-side fitting parts100are provided corresponding to rear side first fitting portions86(to be described below) of a rear movable member62R (to be described below).

The main-body-side fitting parts100are formed in a substantially semi-circle arc shape protruding upward from the top of the LED supporting frame35as seen in a side view, and formed in a substantially flat plate shape having a thickness in the left/right direction.

Fitting holes103are formed at the central portions of the main-body-side fitting parts100.

The fitting holes103are formed in a substantially circular shape as seen in a side view, and are formed to extend in the left/right direction.

The hole diameters of the fitting holes103are substantially the same as the outside diameters of the first fitting portions86(to be described below).

3. LED Unit

Each of the LED units12includes an LED array50(one example of an exposing member), a first frame51that supports the LED array50, a pair of second frames52(seeFIG. 1) that sandwiches the first frame51and a movable mechanism60for moving the LED array50.

(1) LED Array First frame, and Second Frame

The LED array50is disposed at the upper end portions of the LED unit12. The LED array50is formed in a substantially flat plate shape extending in the front/rear direction, and integrally holds a plurality of LEDs arranged in parallel in the front/rear direction. The length of the LED array50in the front/rear direction is shorter than the length of the photosensitive drum15in the front/rear direction, and is longer than the length of the sheet passing area of the photosensitive drum15.

The first frame51is disposed below the LED array50. The first frame51is formed in a substantially rectangular shape extending in the front/rear direction as seen in a side view. The length of the first frame51in the front/rear direction is shorter than the length of the photosensitive drum15in the front/rear direction, and is longer than the length of the LED array50in the front/rear direction. The upper end portion of the first frame51supports the LED array50.

On the first frame51, a plurality of (e.g., two) positioning rollers53and a plurality of (e.g., two) compression springs54are provided.

The plurality of positioning rollers53are formed in a substantially circular plate shape, and are supported on both end faces of the corresponding first frame51such that the positioning rollers53are rotatable. The positioning rollers53are provided to protrude slightly upward from the LED array50, and abut on both end portions of the photosensitive drum15from the lower side.

The plurality of compression springs54are formed in an air-core coil shape, and are disposed at both end portions of the lower surface of the first frame51in the front/rear direction.

The upper end portions of the compression springs54are fixed to the lower surface of the corresponding first frame51, and the lower end portions of the compression springs54are fixed to the upper surface of a holding member63(to be described below).

As shown inFIGS. 1 and 2, the paired second frames52are formed in a substantially flat plate shape extending in the front/rear direction, and are disposed to face each other in the left/right direction with a gap such that the paired second frames52sandwich the corresponding first frame51.

Therefore, the first frame51can slide elastically and vertically between the paired second frames52.

Further, the first frame51is always pressed upward by the compression springs54such that the positioning roller53abuts on the photosensitive drum15.

Therefore, the LED array50is positioned by the positioning roller53such that the LED array50faces the photosensitive drum15from the lower side with gaps (e.g., gaps corresponding to the protruding length of the positioning roller53).

As shown inFIGS. 2 and 3, the movable mechanism60is provided below the pair of second frames52, that is, below the LED array50. The movable mechanism60includes the holding member63, the slide member61, and a movable member62(one example of a second movable member).

(2-1) Holding Member

The holding member63is formed in a substantially rod shape extending in the front/rear direction. The holding member63supports the second frames52and the compression springs54from the lower side (secFIG. 3). That is, the holding member63supports the LED array50through the first frame51and the second frames52.

On the lower surface of the holding member63, LED-side guide parts97and LED-side fitting portions98are provided.

As shown inFIG. 3, the LED-side guide parts97include two front LED-side guide parts97and two rear LED-side guide parts97. The front LED-side guide parts97are provided at the front portion of the lower surface of the holding member63(seeFIG. 2) such that the front LED-side guide parts97face each other in the left/right direction with a gap. The rear LED-side guide parts97are provided at the rear portion of the lower surface of the holding member63(seeFIG. 2) such that the rear LED-side guide parts97face each other in the left/right direction with a gap.

Specifically, the front LED-side guide parts97are provided corresponding to first fitting portions86(to be described below) of the front side of the front movable member62F (to be described below), and the rear LED-side guide parts97are provided corresponding to first fitting portions86(to be described below) of the front side of the rear movable member62R (to be described below).

The LED-side guide parts97are formed in a substantially rectangular shape protruding downward from the lower surface of the holding member63as seen in a side view, and formed in a substantially flat plate shape having a thickness in the left/right direction.

Further, the LED-side guide parts97are disposed such that When the LED-side guide parts97are projected in the vertical direction, the LED-side guide parts97overlap the main-body-side guide parts99.

Guide holes105are formed at the central portions of the LED-side guide parts97.

The guide holes105are formed in a substantially oval shape extending in the front/rear direction as seen in a side view, and extend in the left/right direction.

The major length of each guide hole105is about three times the outside diameter of each first fitting portion86(to be described below), and the minor diameter of each guide hole105is substantially the same as the outside diameter of each first fitting portion86(to be described below).

The LED-side fitting portions98include two front LED-side fitting portions98and two rear LED-side fitting portions98. The front LED-side fitting portions98are provided on the rear side relative to the two front LED-side guide parts97such that the front LED-side fitting portions98face each other in the left/right direction with a gap. The rear LED-side fitting portions98are provided on the rear side relative to the two rear LED-side guide parts97such that the rear LED-side fitting portions98face each other in the left/right direction with a gap (seeFIG. 2).

Specifically, the front LED-side fitting portions98are provided corresponding to both end portions of a second fitting portion90(to be described below) of the front movable member62F (to be described below) in the left/right direction, and the rear LED-side fitting portions98are provided corresponding to both end portions of a second fitting portion90(to be described below) of the rear movable member62R (to be described below) in the left/right direction.

The LED-side fitting portions98are formed in a substantially semi-circle arc shape bulging downward from the lower surface of the holding member63as seen in a side view, and formed in a substantially flat plate shape having a thickness in the left/right direction.

The LED-side fitting portions98are disposed such that when the LED-side fitting portions98are projected in the vertical direction, the LED-side fitting portions98overlap the main-body-side fitting parts100.

Fitting holes106are formed at the central portions of the LED-side fitting portions98.

The fitting holes106are formed in a substantially circular shape as seen in a side view, and extend in the left/right direction.

The hole diameters of the fitting holes106are substantially the same as the outside diameters of the second fitting portions90(to be described below).

(2-2) Slide Member

The slide member61is formed in a substantially rod shape extending in the front/rear direction. The slide member61is disposed on the upper surface of the LED supporting frame35such that the slide member61is slidable along the front/rear direction with respect to the main body casing2.

Specifically, as shown inFIG. 4, the slide member61integrally includes a pressed portion65, a first engagement portion67, a connection portion69, a main body portion73, and a second engagement portion68.

The pressed portion65is provided at the front end portion of the slide member61, and is formed in a substantially L shape in a side view.

The first engagement portion67is provided continuously on the rear side of the pressed portion65such that the first engagement portion67corresponds to the front end portion of a second link member83(to be described below) of the front movable member62F (to be described below).

The first engagement portion67includes a pair of first supporting portions70and an inclined portion71.

The paired first supporting portions70are formed from both end portions of the rear end portion of the pressed portion65in the left/right direction, formed in a substantially flat plate shape protruding toward the rear side, and are disposed to face each other in the left/right direction with a gap.

Each of the paired first supporting portions70includes an insertion hole75and first guide bosses76formed at the front end portion of the corresponding first supporting portion70.

The insertion holes75are formed in substantially circular shapes facing each other in a side view, and extend in the left/right direction. The hole diameters of the insertion holes75are substantially the same as the outside diameter of an insertion shaft94(to be described below).

The first guide bosses76are formed in a substantially cylindrical shape protruding outward in the left/right direction from the circumferential end portions of the insertion holes75.

The inclined portion71is provided between the paired first supporting portions70on the rear side relative to the insertion hole75(the first guide bosses76), and is formed in a substantially triangular shape in a side view. Specifically, the upper surface of the inclined portion71is formed to be inclined upward as it goes to the rear side.

The connection portion69is formed in a substantially flat plate shape extending from the rear end portion of the inclined portion71toward the rear side, and has a section shape extending in the vertical direction.

The main body portion73is formed in a substantially rod shape extending in the front/rear direction, and formed in a substantially semi-circle arc shape such that the front end portion of the main body portion73bulges toward the front side as seen in a side view. The central portion of the front end portion of the main body portion73in the left/right direction is connected to the rear end portion of the connection portion69.

The second engagement portion68is provided continuously from the rear side of the main body portion73such that the second engagement portion68corresponds to the front end portion of the second link member83(to be described below) of the rear movable member62R (to be described below).

The second engagement portion68includes a pair of second supporting portions78.

The paired second supporting portions78are formed from bath end portions of the rear end portion of the main body portion73in the left/right direction, formed in a substantially flat plate shape protruding toward the rear side, and are disposed to face each other in the left/right direction with a gap.

Each of the paired second supporting portions78includes an insertion hole79and a second guide boss80formed at the front end portion of the corresponding second supporting portion78.

The insertion holes79are formed in substantially circular shapes facing each other in a side view, and extend in the left/right direction.

The second guide bosses80are formed in a substantially cylindrical shape protruding outward in the left/right direction from the circumferential end portions of the insertion holes79. The outside diameters of the second guide bosses80are substantially the same as the outside diameters of the first guide bosses76.

(2-3) Movable Members

As shown inFIG. 2, the movable member62has a pantograph mechanism. The movable member62includes a front movable member62(hereinafter, referred to as a movable member62F) and a rear movable member62(hereinafter, referred to as a movable member62R).

The front movable member62F is provided such that when the front movable member62F is projected in the vertical direction, the front movable member62F overlaps the front end portion of the LED array50. The rear movable member62R is provided such that when the rear movable member62R is projected in the vertical direction, the rear movable member62R overlaps the rear end portion of the LED array50. That is, the two movable members62are provided to support both end portions of the LED array50in the front/rear direction, through both end portions of the holding member63(to be described below), respectively.

As shown inFIG. 4, each of the movable members62includes a pair of first link members82and a second ring member83.

The paired first link members82are disposed to face each other in the left right direction with a gap.

Each of the paired first link members82is formed in a substantially U shape open outward in the left/right direction as seen in a plan view, and includes a first flat plate portion85and two first fitting portions86.

The first fiat plate portions85are formed in a substantially flat plate shape, and have section shapes extending in the vertical direction. Through-holes87are formed at the central portions of the first flat plate portions85.

The through-holes87are formed in a substantially circular shape in a side view, and extend in the left/right direction. The hole diameters of the through-holes87are substantially the same as the outside diameter of a corresponding shaft part95(to be described below).

The two first fitting portions86are provided at both end portions of the corresponding first flat plate portion85in the front/rear direction, and are formed in a substantially cylindrical shape protruding outward in the left/right direction from the outer face of the corresponding first flat plate portion85in the left/right direction.

The second ring member83is formed in a substantially T shape in a plan view, and includes a second flat plate portion89and the second fitting portion90.

The second flat plate portion89is formed in a substantially flat plate shape, and has a section shape extending in the vertical direction. The length of the second flat plate portion89in a longitudinal direction is substantially the same as the length of each first fiat plate portion85in the longitudinal direction.

A through-hole91and an insertion hole92are formed at the second flat plate portion89.

The through-hole91is formed in a circular shape in a side view such that the through-hole91passes through the central portion of the second flat plate portion89. The hole diameter of the through-hole91is slightly larger than the outside diameter of the shaft part95(to be described below).

The insertion hole92is formed in a substantially circular shape in a side view such that the insertion hole92passes through the front end portion of the second flat plate portion89. The hole diameter of the insertion hole92is slightly larger than the outside diameter of the insertion shaft94(to be described below).

The second fitting portion90is formed in a substantially cylindrical shape extending in the left/right direction, and the central portion of the lower front side of the second fitting portion90in the left/right direction is connected to the rear end portion of the second flat plate portion89.

As shown inFIG. 3, one pair of first link members82and the second link member83are disposed such that the second flat plate portion89is disposed between the first flat plate portions85and intersect with the first flat plate portions85in the form of an X, and then a shaft part95having a substantially cylindrical shape is inserted into the two through-holes87and the through-hole91, whereby the first flat plate portions85and the second link member83are connected so as to be rotatable with respect to each other (seeFIG. 4). That is, the pair of first link members82and second link member83intersect with each other and are pivotably supported by the shaft part95such that the first link members82and second link member83are rotatable on each other.

The front end portion of the second fiat plate portion89of the front movable member62F is disposed between the paired first supporting portions70. An insertion shaft94having a substantially cylindrical shape is inserted into the two first guide bosses76, the two insertion holes75and the insertion hole92. Accordingly, the front end portion of the second flat plate portion89is fixed to the first engagement portion67such that the front end portion of the second flat plate portion89and the first engagement portion67are rotatable with respect to each other. Further, in the front movable member62F, the rear end portions of the paired first flat plate portions85are disposed to sandwich the connection portion69from both sides in the left/right direction.

The front end portion of the second flat plate portion89of the rear movable member62R is disposed between the paired second supporting portions78. An insertion shaft94having a substantially cylindrical shape is inserted into the two second guide bosses80, the two insertion holes79, and the insertion hole92, whereby the front end portion of the second flat plate portion89is fixed to the second engagement portion68such that the front end portion of the second flat plate portion89and the second engagement portion68are rotatable with respect to each other.

In this way, the front end portions of the two second link members83are fixed to the slide member61such that the two second link members83and the slide member61are rotatable with respect to each other, and the front movable member62F and the rear movable member62R are connected to the slide member61.

The slide member61and the movable members62are held by the holding member63and the LED supporting frame35as shown inFIG. 2.

Specifically, while the first fitting portions86of the front sides (upper sides) of the first link members82are fit into the guide holes105of corresponding LED-side guide parts97from the inner side, the first fitting portions86of the rear sides (lower sides) of the first link members82are fit into the fitting holes103of corresponding main-body-side fitting parts100from the inner side.

In this way, the front-side first fitting portions86are held by the LED-side guide parts97such that the front-side first fitting portions86are movable in the front/rear direction and the front-side first fitting portions86and the LED-side guide parts97are rotatable with respect, to each other, and the rear-side first fitting portions86are fixed to the main-body-side fitting parts100such that the rear-side first fitting portions86and the main-body-side fitting parts100are rotatable with respect to each other.

That is, the rear end portions of the two first link members82are fixed to the main body casing2such that the two first link members82and the main body casing2are rotatable with respect to each other, and the front end portions of the two first link members82are held by the holding member63such that the two first link members82are movable the front/rear direction and the two first link members82and the holding member63are rotatable with respect to each other.

Further, the first guide bosses76and the second guide bosses80of the slide member61are fit into corresponding main-body-side guide parts99from the inner side in the left/right direction, and both end portions of the second fitting portion90of each second link member83in the left/right direction are fit into corresponding fitting holes106of a corresponding LED-side fitting portion98from the inner side in the left/right direction.

In this way, the first guide bosses76and the second guide bosses80are held by the main-body-side guide parts99such that the first guide bosses76and the second guide bosses80are movable along the front/rear direction, and both end portions of each second fitting portion90in the left/right direction are fixed to corresponding LED-side fitting portions98such that the second fitting portion90is relatively rotatable.

That is, the rear end portions of the two second link members83are fixed to the holding member63such that the two second link members83and the holding member63are rotatable with respect to each other, and the front end portions of the two second link members83are held to be movable in the front/rear direction with respect to the main body casing2.

In this way, the front and rear end portions of the holding member63are supported from the lower side by the front movable member62F and the rear movable member62R, respectively.

The slide member61is provided to be slidable along the front/rear direction between a first position (seeFIG. 2) and a second position (seeFIG. 5A). In a state where the front cover5is at a closed position, the slide member61is at the first position, and the front end portion of the pressed portion65abuts on the rear surface of the front cover5. Further, in a state where the front cover5is in an open position, the slide member61is at the second position, and the front end portion of the pressed portion65protrudes outward from the main body casing2. That is, the slide member61is slidable along the front/rear direction in accordance with the opening/closing operation of the front cover5.

As shown inFIG. 5B, the compression springs101press the first guide bosses76(the second guide bosses80) toward the front side through the covering parts102, whereby the slide member61is always pressed toward the front side such that the slide member61is disposed at the second position. That is, the compression springs101press the slide member61from the first position toward the second position.

Further, as shown inFIG. 2, in a state where the slide member61is at the first position, the movable members62are disposed at rising positions such that the first flat plate portions85and the second flat plate portions89form intersection angles θ (angles formed on the holding member (63) side) of, for example, 60° to 120°. At this time, the LED array50is disposed at exposure positions close to the photosensitive drum15such that the positioning roller53abuts on the photosensitive drum15and the LED array50exposes the photosensitive drum15.

Further, in a state where the slide member61is at the second position, the movable members62are disposed at tilting positions where the movable members62are tilted toward the LED supporting frame (35) side such that the intersection angles θ are larger than those at the rising positions. At this time, the LED array50is disposed at the evacuation position (seeFIG. 5A) such that the positioning roller53is distant from the photosensitive drum15and the LED array50is evacuated from the photosensitive drum15.

That is, in accordance with the sliding of the slide member61, the movable member62moves the LED array50between the exposure position and the evacuation position.

Incidentally, the intersection angles θ at the tilting positions are, for example, 140° to 170°. Further, at the tilting positions, the lower end portion of the second flat plate portion89of the front movable member62F is in contact with the inclined portion71.

4. Mount and Removal of Drum unit with Respect to Main Body Casing

Now, mount and removal of the drum unit10with respect to the main body casing2will be described.

As shown inFIG. 2, in a state where the front cover5is at the closed position, the pressed portion65are pressed toward the rear side against the pressing forces of the compression springs101(seeFIG. 5B) by the rear surface of the front cover5, whereby the slide member61is disposed at the first position.

At this time, the movable member62is disposed at the rising position, and the LED array50is disposed at the exposure position.

After the drum unit10is mounted in the main body casing2, in order to pull (remove) the drum unit10out of (from) the main body casing2, as shown inFIG. 5A, first, the front cover5is moved from the closed position (seeFIG. 2) to the open position, whereby the main opening4is opened such that the drum-unit accommodating part36and the outside of the main body casing2are connected through the main opening4.

Then, the pressing of the front cover5on the slide member61is released, and the first guide bosses76are pressed toward the front side by the pressing forces of the compression springs101, whereby the first guide bosses76and the second guide bosses80are guided along the front/rear direction by corresponding main-body-side guide parts99. Therefore, the slide member61is moved toward the front side and slides along the front/rear direction from the first position to the second position.

In this case, the front end portion of the second flat plate portion89of the front movable member62F is moved toward the front side with movement of the first guide bosses76, and the front end portion of the second flat plate portion89of the rear movable member62R is moved toward the front side with movement of the second guide bosses80.

Then, the front-side first fitting portions86of the first link members82are moved toward the front side while rotating with respect to the LED-side guide parts97, in corresponding guide holes105(seeFIG. 3).

At this time, the rear-side first fitting portions86rotate inside corresponding fitting holes103(seeFIG. 3), and the second fitting portions90of the second link members83rotate inside corresponding fitting holes106(seeFIG. 2).

In this way, the movable members62are moved from the rising positions to the tilting positions.

Then, the front movable members62F and the rear movable members62R move the front end portion and rear end portion of the LED array50toward the lower side, respectively, at the same time. According thereto, the movable members62move the front and rear end portions of the LED array50at the same time, so as to move the LED array50in parallel from the exposure position to the evacuation position.

That is, the slide member slides in accordance with the movement of the front cover5from the closed position to the open position, and the LED array50moves from the exposure position to the evacuation position in accordance with the sliding of the slide member61.

Thereafter, when a user applies a force to pull the drum unit10toward the front side, the drum unit10moves downward, moves toward the front side, and is pulled out of the drum-unit accommodating part36along the front/rear direction through the main opening4. At this time, the drum unit10is moved such that the mount/removal grooves46of the drum frames32pass the upper end portions of the developing units11.

Then, when the user further pulls the drum unit10toward the front side, the drum unit10is removed from the main body casing2.

Therefore, the removal of the drum unit10from the main body casing2is completed.

Subsequently, mount of the drum unit10into the main body casing2will be described.

In order to mount the drum unit10into the drum-unit accommodating part36of the main body casing2, an operation is performed in a reverse procedure to that of the above-mentioned pullout (removal) operation.

Specifically, as shown inFIG. 5A, the drum unit10is inserted toward the drum-unit accommodating part36through the main opening4, and is accommodated in the drum-unit accommodating part36.

Next, the front cover5is moved from the open position to the closed position.

Then, as shown inFIG. 2, the pressed portion65of the slide member61is pressed by the front cover5, whereby the slide member61is moved from the second position to the first position.

At this time, in accordance with the movement of the slide member61from the second position to the first position, the movable members62move from the tilting positions to the rising positions.

Then, the front movable member62F and the rear movable member62R move the front end portion and rear end portion of the LED array50toward the upper side, respectively, at the same time. In this way, the movable members62move the LED array50in parallel from the evacuation positions to the exposure positions.

In this case, at the exposure positions, the positioning rollers53of the first frames51abut on the circumferential surfaces of the photosensitive drums15, and the LED array50is positioned with respect to the photosensitive drum15.

That is, in accordance with the movement of the front cover5from the open position to the closed position, the slide member61slides, and the LED array50moves from the evacuation position to the exposure position in accordance with the sliding of the slide member61.

Therefore, the mount of the drum unit10into the main body casing2is completed.

(1) The printer1according to the exemplary embodiment of the present invention includes the movable member62in addition to the slide member62, as shown inFIG. 2. Therefore, so long as the movable member62secures an amount of movement of the slide member61corresponding to an amount of displacement of the LED array50between the exposure positions and the evacuation positions, it is possible to surely move the LED array50between the exposure position and the evacuation position.

Therefore, it is possible to reduce the amount of movement of the slide member61, as compared to a configuration without the movable member62.

As a result, it is possible to surely move the LED array50between the exposure position and the evacuation position, and to reduce a size of the printer1.

Further, the movable member62includes the front movable member62F and the rear movable member62R, and when the movable member62moves the LED array50, the front movable member62F and the rear movable member62R move the front end portion and rear end portion of the LED array50, respectively, at the same time.

Therefore, the movable member62can move the front and rear end portions of the LED array50at the same time.

As a result, it is possible to move the LED array50in parallel, and to prevent the LED array50from getting kinked.

Therefore, it is possible to suppress the LED array50from being damaged, and to prevent undesirable contact of the LED array50with the photosensitive drums15.

Further, when the movable member62moves the LED array50from the evacuation position to the exposure position, it is possible to surely make the positioning roller53abut on the photosensitive drum15. Therefore, it is possible to improve the accuracy of relative positioning of the photosensitive drum15and the LED array50at the exposure position.

Further, the slide member61slides along the front/rear direction, whereby the movable mechanism60moves the LED array50between the exposure position and the evacuation position. Therefore, it is possible to reduce interruption of the movable mechanism60when the drum unit10or the developing unit11is mounted into or removed from the main body casing2along the front/rear direction (e.g., the axial direction of the photosensitive drum15).

(2) The LED array50is disposed to face the photosensitive drum15from the lower side, and the movable mechanism60is provided below the LED array50.

Therefore, in a case where the movable member62moves the LED array50from the exposure position to the evacuation position as shown inFIG. 5A, it is possible to surely position the LED array50at the evacuation position by gravity.

On the other hand, in a case where the movable member62moves the LED array50from the evacuation position to the exposure position as shown inFIG. 2, since the movable member62is provided to support both end portions of the LED array50, it is possible to surely position the LED array50at the exposure position against gravity.

Therefore, it is possible to surely move the LED array50between the exposure position and the evacuation position.

As shown inFIG. 5Asince the movable mechanism60is disposed across the LED array50from the photosensitive drum15, the movable mechanism60is sufficiently distant from the pullout track of the drum unit10from the main body casing2. Therefore, during the operation of pulling the drum unit10out of the main body casing2, it is possible to suppress interference between the drum unit10and the movable mechanism60, and to smoothly pull the drum unit10out of the main body casing2.

Further, since the movable mechanism60is disposed across the LED array50from the photosensitive drum15, it is possible to narrow the intervals between adjacent developing units11(seeFIG. 1).

Therefore, it is possible to reduce the size of the printer1in the arrangement direction of the plurality of (e.g., four) developing units11, that is, the left/right direction.

(3) As shown inFIG. 1, the plurality of (e.g., four) photosensitive drums15are provided corresponding to multiple colors (black, yellow, magenta, and cyan) and are arranged at intervals in the left/right direction.

Therefore it is possible to form full color images.

Further, since the slide member61slides along the front/rear direction, whereby the movable mechanism60moves the LED array50between the exposure position and the evacuation position, it becomes unnecessary to secure a space for moving the LED array50in the left/right direction.

Therefore, it is possible to narrow intervals between axes of adjacent photosensitive drums15, to form full color images, and to further downsize the printer1.

(4) The slide member61is slidable between the first position which is the position of the slide member61in a state where the front cover5is at the closed position as shown inFIG. 2and the second position which is the position of the slide member61in a state where the front cover5is at the open position as shown inFIG. 5A. Further, the main-body-side guide part99includes the compression spring101configured to press the slide member61from the first position toward the second position as shown inFIG. 5B.

Therefore, it is possible to simplify the configuration of the printer3, and to surely make the slide member61slide between the first position and the second position in accordance with the opening/closing operation of the front cover5.

As a result, it is possible to surely link the opening/closing operation of the front cover5and the sliding of the slide member61.

(5) The movable mechanism60includes the holding member63for holding the LED array50as shown inFIG. 2. Further, the movable member62includes one pair of first link members82and a second link member83as shown inFIG. 3. The pair of first link members82and the second link member83are disposed to intersect with each other such that the second flat plate portion89is disposed between paired first flat plate portions85, and form an X shape together with the paired first flat plate portions85, and then a shaft part95having a substantially cylindrical shape is inserted into the two through-holes87and the through-hole91, whereby the pair of first link members82and second link member83are connected to be rotatable with respect to each other (seeFIG. 4)

Further, as shownFIG. 2, in a state where the slide member61is at the first position, the movable member62is disposed at rising positions such that the first flat plate portions85and the second fiat plate portions89form intersection angles θ (angles formed on the holding member (63) side) of, for example, 60° to 120°. Meanwhile, in a state where the slide member61is at the second position, the movable member62is disposed at tilting positions where the movable member62is tilted toward on the LED supporting frame (35) side such that the intersection angles θ are larger than those at the rising positions.

Therefore, in accordance with the movement of the front cover5from the closed position to the open position, the slide member61slides, and in accordance with the sliding of the slide member61, the movable member62moves from the tilting position to the rising position, thereby moving the LED array50from the exposure position to the evacuation position.

On the other hand, the slide member61slides in accordance with the movement of the front cover5from the open position to the closed position, and the LED array50moves from the evacuation position to the exposure position in accordance with the sliding of the slide member61.

As a result, it is possible to secure a larger amount of displacement of the movable member62with respect to the amount of movement of the slide member61.

Therefore, even if the amount of movement of the slide member61is reduced, it is possible to surely move the LED array50between the exposure position and the evacuation position, and thus it is possible to further reduce the size of the printer1.

Further, the front movable member62F and the rear movable member62R are provided to support the front and rear end portions of the LED array50through the front and rear end portions of the holding member63, respectively. That is, the front and rear end portions of the holding member63are supported from the lower side by the front movable member62F and the rear movable member62R, respectively.

Therefore, it is unnecessary to additionally provide members other than the holding member63for supporting the LED array50(or simplification is possible). As a result, it is possible to reduce the number of components, and to reduce the size of the printer1, specifically, reduce the size of the printer1in the left/right direction.