Image-forming apparatus

This application claims priority from Japanese Patent Application No. 2011-074672 filed Mar. 30, 2011. The entire content of the priority application is incorporated herein by reference.

The present invention relates to an image-forming apparatus on which a process cartridge is mountable.

A well-known image-forming apparatus includes a casing whose upper portion is formed with an opening, a top cover configured to open and close the opening and an LED head supported by the top cover and having an exposing surface facing downward. When the top cover is closed to mount a process cartridge including a photosensitive drum in the casing, the exposing surface of the LED head opposes the photosensitive drum to expose the photosensitive drum. Further, the LED head is retracted from the process cartridge when the top cover is opened, thereby enabling the process cartridge to be replaced easily.

A construction that supports the LED head by the casing instead of the top cover is conceivable. However, in this construction, the process cartridge should be inserted deep into a position below the exposing surface of the LED head from above (from a side opposite to the exposing surface). Conceivably, mounting of this process cartridge may involve difficulty.

In view of the foregoing, it is an object of the present invention to provide an image-forming apparatus capable of easily mounting a process cartridge from a side opposite to an exposing surface of an LED head supported by a casing.

In order to achieve the above and other objects, there is provided an image-forming apparatus including: a process cartridge including a photosensitive drum having a photosensitive surface and a rotational axis; an exposing unit having a first end, a second end opposing the first end, and an exposing surface formed on the first end and oriented in a predetermined direction; and a supporting member on which the process cartridge is mountable from a side of the second end. The supporting member has a pivotal supporting portion configured to pivotably movably support the process cartridge between an exposing position where the photosensitive surface of the photosensitive drum faces the exposing surface and a retracted position where the photosensitive surface of the photosensitive drum is offset from the exposing surface, the exposing surface being configured to expose the photosensitive surface of the photosensitive drum to form an electrostatic latent image when the process cartridge is positioned at the exposing position.

In the drawings:

FIG. 1 is a view showing an internal construction of a color printer according to an embodiment of the present invention, the color printer incorporating a drawer in which a plurality of process cartridges is mounted;

FIG. 2 is a cross-sectional view showing an LED unit provided on the drawer and a photosensitive drum of the process cartridge;

FIG. 3 is a view showing a state where the drawer is taken out of the color printer of FIG. 1 , the process cartridge having a pivot shaft;

FIG. 4 is an explanatory view showing a process for mounting the photosensitive drum on the drawer;

FIG. 5 is a perspective view showing the process cartridge and the LED unit when the process cartridge is mounted in the drawer;

FIG. 6 is view showing the process cartridge according to the embodiment and a drawer according to a first modification of the present embodiment, wherein the process cartridge is mounted in the drawer;

FIG. 7 is a view showing a state where the process cartridge of FIG. 6 is pivotally moved to a retracted position where the process cartridge can be detached from the drawer of FIG. 6 ;

FIG. 8 is a view showing a state where the process cartridge of FIG. 6 is removed from the drawer of FIG. 6 ;

FIG. 9 is a view showing a process cartridge and a drawer according to a second modification of the present embodiment, the drawer being provided with a pivot member to be engaged with the process cartridge, wherein the process cartridge is mounted in the drawer;

FIG. 10 is a view showing a state where the process cartridge of FIG. 9 is pivotally moved to a retracted position where the process cartridge can be detached from the drawer of FIG. 9 ; and

FIG. 11 is a view showing a state where the process cartridge of FIG. 9 is disengaged from the pivot member of the drawer of FIG. 9 .

<General Configuration of Color Laser Printer 1 >

First, a general configuration of a color printer 1 as an example of an image-forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 .

In the following description, a left side in FIG. 1 will be referred to as a front side, while a right side in FIG. 1 will be referred to as a rear side. The terms “upward”, “downward”, “upper”, “lower”, “above”, “below”, “beneath”, “right”, “left”, “front”, “rear” and the like will be used assuming that the color printer 1 is viewed from its front side. That is, a near side in FIG. 1 will be referenced as a right side, while a far side in FIG. 1 will be referenced as a left side.

As shown in FIG. 1 , the color printer 1 includes a main body 2 within which a sheet feeding unit 3 , an image forming unit 4 and a sheet discharging unit 5 are disposed.

The main body 2 is formed in a box shape having a substantially rectangular shape in a side view. A front cover 23 is pivotably movably provided at a lower portion of the front side of the main body 2 . When the front cover 23 is opened, an opening 24 formed on the front side of the main body 2 is exposed to outside (see FIG. 3 ).

The sheet feeding unit 3 is arranged at a lower portion of the main body 2 . The sheet feeding unit 3 includes a sheet tray 31 for accommodating sheets S therein, a lifter plate 32 , and a sheet conveying mechanism 33 . The sheet S accommodated within the sheet tray 31 is lifted upward by the lifter plate 32 , and is conveyed to the image forming unit 4 by the sheet conveying mechanism 33 . As shown by a thick solid line in FIG. 1 , the sheet S stacked in the sheet tray 31 is first conveyed frontward and then makes a U-turn to be conveyed rearward.

The image forming unit 4 includes four LED units 41 as an example of an exposing unit, four process cartridges 42 each corresponding to each LED unit 41 , a transfer unit 43 , and a fixing unit 44 .

The four LED units 41 are supported to a drawer 60 (described later).

As shown in FIG. 2 , each LED unit 41 includes an LED head 411 , a supporting frame 412 that supports the LED head 411 , a coil spring 413 , and a base portion 414 supporting the supporting frame 412 via the coil spring 413 . The LED head 411 is configured of a plurality of LEDs and has an exposing surface 411 A configured to face a photosensitive surface of a photosensitive drum 42 A when the process cartridge is mounted on the drawer 60 .

More specifically, as shown in FIG. 1 , the supporting frame 412 has a substantially rectangular shape in a side view whose length in the front-to-rear direction is smaller than that in a top-to-bottom direction (vertical direction). Further, the length of the supporting frame 412 in the front-to-rear direction is also smaller than that in the left-to-right direction, as shown in FIGS. 1 and 2 . Each of the base portion 414 and the LED head 411 also has an elongated shape extending in the left-to-right direction.

As shown in FIG. 2 , a guide roller 412 A is rotatably provided on each end of the supporting frame 412 in the left-to-right direction. Each guide roller 412 A is biased toward the photosensitive surface of the photosensitive drum 42 A by the coil spring 413 so as to contact with the corresponding photosensitive drum 42 A, when the process cartridge 42 is mounted on the drawer 60 . Due to the contact of the guide roller 412 A with the photosensitive drum 42 A, the exposing surface 411 A of the LED head 411 can stay away from the photosensitive surface of the photosensitive drum 42 A by a prescribed distance.

The four process cartridges 42 are detachably mounted on the drawer 60 and juxtaposed therein in the front-to-rear direction. Each process cartridge 42 includes the photosensitive drum 42 A and a developing unit 42 B configured to supply developer (toner in the present embodiment) to the photosensitive drum 42 A, as shown in FIG. 1 .

The developing unit 42 B includes a developing roller B 1 , a supply roller B 2 , a thickness-regulation blade B 3 , and a toner accommodating section B 4 . Each process cartridge 42 stores toner of a different color, but has a construction substantially identical to one another.

More specifically, as shown in FIGS. 1 and 3 , when the process cartridge 42 is mounted on the drawer 60 , the toner accommodating section B 4 is positioned diagonally frontward and upward of the corresponding LED unit 41 . The supply roller B 2 is positioned below the toner accommodating section B 4 . The developing roller B 1 is positioned downward and rearward of the supply roller B 2 , and the photosensitive drum 42 A is positioned downward and rearward of the developing roller B 1 . The photosensitive drum 42 A has a rotational shaft A 1 about which the photosensitive drum 42 A is rotatable.

The process cartridge 42 has a front surface curving rearward in conformance with outer profiles of the toner accommodating section B 4 , the supply roller B 2 , the developing roller B 1 and the photosensitive drum 42 A. More specifically, as shown FIG. 3 , the front surface of the process cartridge 42 has a curvature gradually becoming greater as extending downward.

As shown in FIG. 1 , the drawer 60 on which the process cartridges 42 are mountable includes four chargers 60 A and four cleaning rollers 60 B as an example of a cleaning member, in correspondence with the four process cartridges 42 . The charger 60 A is configured to charge the photosensitive drum 42 A. The cleaning roller 60 B is configured to be in contact with the photosensitive drum 42 A for removing foreign matters (toner, paper dusts, and so on) therefrom.

More specifically, the charger 60 A and the cleaning roller 60 B are disposed rearward of the corresponding photosensitive drum 42 A, while the developing roller B 1 and the supply roller B 2 are disposed frontward of the photosensitive drum 42 A. In other words, with respect to a rotational direction (a counterclockwise direction in FIG. 1 ) of the photosensitive drum 42 A, the cleaning roller 60 B, the charger 60 A and the LED unit 41 are arranged upstream to downstream in the rotational direction.

The transfer unit 43 is disposed above the sheet tray 31 and below the mounted process cartridges 42 , as shown in FIG. 1 . The transfer unit 43 includes a drive roller 43 A, a follower roller 43 B, an endless belt 43 C mounted on the drive roller 43 A and the follower roller 43 B in a taut state, and four transfer rollers 43 D. The endless belt 43 C has an outer circumferential surface with which each photosensitive drum 42 A is in contact. The four transfer rollers 43 D are disposed within an internal space formed by the endless belt 43 C such that the endless belt 43 C is nipped between each transfer roller 43 D and its corresponding photosensitive drum 42 A.

The fixing unit 44 is disposed reward of the mounted process cartridges 42 . The fixing unit 44 includes a cylindrical-shaped heat roller 44 A, a pressure roller 44 B and a heater H. The pressure roller 44 B is disposed in opposition to the heat roller 44 A for applying pressure to the same and the heater H is disposed within the heat roller 44 A for heating the same.

With the construction described above, the photosensitive surface of the photosensitive drum 42 A is charged by the charger 60 A, and then exposed to light by the LED unit 41 in accordance with print data. An electrostatic latent image is thus formed on the photosensitive surface of the photosensitive drum 42 A. In the meantime, toner within the toner accommodating section B 4 is supplied to the developing roller B 1 via the supply roller B 2 , enters between the developing roller B 1 and the thickness-regulation blade B 3 , and is carried on the developing roller B 1 as a thin layer of uniform thickness.

As the photosensitive drum 42 A rotates in the counterclockwise direction in FIG. 1 , the toner borne on the developing roller B 1 is supplied to the electrostatic latent image formed on the photosensitive surface of the photosensitive drum 42 A, thereby developing the electrostatic latent image into a visible toner image. The toner image formed on the photosensitive surface of each photosensitive drum 42 A is then sequentially superimposed and transferred onto the sheet S, as the sheet S supplied from the sheet feeding unit 3 passes between each photosensitive drum 42 A and the endless belt 43 C (corresponding transfer roller 43 D).

The sheet S on which the toner image is transferred is then conveyed to the fixing unit 44 . As the sheet S passes between the heat roller 44 A and the pressure roller 44 B, the toner image transferred on the sheet S is thermally fixed thereon. In this way, images can be formed on the sheet S.

The image-formed sheet S is then conveyed to the sheet discharging unit 5 from the fixing unit 44 (the image forming unit 4 ).

The sheet discharging unit 5 includes a sheet discharging path 51 and discharge rollers 52 . The image-formed sheet S is conveyed to the sheet discharging path 51 from the fixing unit 44 , then directed frontward, and finally discharged by the discharge rollers 52 onto a discharge tray 22 formed outside of the main body 2 .

In case that another image needs to be formed on another side of the sheet S (double-side printing), the discharge rollers 52 is caused to rotate inversely before the sheet S is completely discharged out of the main body 2 . The sheet S is drawn back within the main body 2 and conveyed along a bottom portion of the main body 2 back to the image forming unit 4 , as indicated by a thick broken line in FIG. 1 .

<Detailed Constructions of Process Cartridge 42 and Drawer 60 >

Next, detailed configurations of the process cartridge 42 and the drawer 60 will be described with reference to FIGS. 3 through 5 .

The process cartridge 42 is detachably mountable on the drawer 60 . As shown in FIG. 3 , the drawer 60 has a substantially rectangular parallelepiped shape whose upper surface is opened. The process cartridge 42 is mountable on the drawer 60 from above (from a side opposite to the exposing surface 411 A of the LED unit 41 ). In other words, the LED unit 41 is disposed on the drawer 60 such that the exposing surface 411 A is oriented downward, so that the exposing surface 411 A cannot be viewed in a path in which the process cartridge 42 is mounted and removed.

As show in FIGS. 3 and 5 , the process cartridge 42 has a pivot shaft 421 at an upper-rear end portion. Specifically, the pivot shaft 421 is disposed rearward of the toner accommodating section B 4 . In the vertical direction, the pivot shaft 421 is positioned below an upper portion of the developing unit 42 B so as not to protrude upward therefrom. The pivot shaft 421 protrudes outward from each of left and right walls of the process cartridge 42 .

The drawer 60 includes a pair of side walls (left and right) 61 , a front wall and a rear wall (shown without reference numerals in FIG. 3 ). The front wall and the rear wall connect front and rear end portions of the side walls 61 , respectively. The drawer 60 detachably supports the four process cartridges 42 between the pair of side walls 61 . The four LED units 41 (more specifically, the base portion 414 of each process cartridge 42 ) are also supported by the pair of side walls 61 .

In FIG. 3 , the drawer 60 is illustrated as being completely separated (detached) from the main body 2 , but the drawer 60 may be configured not to be detached from the main body 2 .

Each side wall 61 is formed with four pairs of a bearing groove 611 and a releasing groove 612 . Each bearing groove 611 is adapted to receive the pivot shaft 421 of the each process cartridge 42 . Each releasing groove 612 is adapted to receive the rotational shaft A 1 of the photosensitive drum 42 A so that the process cartridge 42 can move along the releasing groove 612 .

Each bearing groove 611 has a substantially U-shape. The bearing groove 611 extends from an upper edge of the corresponding side wall 61 down to a position above the corresponding LED head 411 . The bearing groove 611 has a width in the front-to-rear direction that gradually becomes greater as approaching to the upper edge of the side wall 61 .

Each bearing groove 611 has a bottom end portion serving as a shaft-supporting portion 611 A. The shaft-supporting portion 611 A has a substantially semi-circular shape. Each pivot shaft 421 of each process cartridge 42 is inserted from above into the corresponding bearing groove 611 , guided along the bearing groove 611 , and finally received at the shaft-supporting portion 611 A. The shaft-supporting portion 611 A thus rotatably supports the pivot shaft 421 of the process cartridge 42 .

Each releasing groove 612 is a substantially J-shaped groove, extending from the upper edge of the corresponding side wall 61 downward to a position close to a bottom end portion of the side wall 61 and then curving downward and rearward. Specifically, the releasing groove 612 has a straight portion 612 C and an arcuate portion 612 A. The straight portion 612 C extends substantially vertically with a width greater than a diameter of the rotational shaft A 1 of the photosensitive drum 42 A. The arcuate portion 612 A extends downward and rearward from the straight portion 612 C. The arcuate portion 612 A is one part of a circle whose center is the shaft-supporting portion 611 A. The arcuate portion 612 A has a rear end portion 612 B whose width is slightly smaller than the diameter of the rotational shaft A 1 of the photosensitive drum 42 A. The distance between the shaft-supporting portion 611 A and the arcuate portion 612 A is substantially identical to the distance between the pivot shaft 421 and the rotational shaft A 1 of the photosensitive drum 42 A.

As shown in FIG. 4( a ), for mounting the process cartridge 42 on the drawer 60 , the rotational shaft A 1 of the photosensitive drum 42 A is inserted into the corresponding releasing grooves 612 , while the pivot shaft 421 of the process cartridge 42 is inserted into the corresponding bearing grooves 611 from above.

Then, as shown in FIG. 4( b ), when the rotational shaft A 1 is brought to contact with the arcuate portion 612 A of each bearing groove 611 (more specifically, at a upper end portion of the arcuate portion 612 A) in a state where the pivot shaft 421 contacts with the shaft-supporting portion 611 A of each bearing groove 611 , the rotational shaft A 1 is prevented from moving further downward.

A user then pivotally moves the process cartridge 42 about the pivot shaft 421 in the counterclockwise direction. Accordingly, as shown in FIG. 4( c ), the photosensitive drum 42 A is slidingly moved along the arcuate portion 612 A to reach the rear end portion 612 B, whereby the photosensitive surface of the photosensitive drum 42 A can face the exposing surface 411 A of the LED head 411 . At this time, since the rotational shaft A 1 of the photosensitive drum 42 A is pinched by the rear end portion 612 B having a narrower width than the diameter of the rotational shaft A 1 of the photosensitive drum 42 A, the photosensitive drum 42 A can be positioned relative to the side walls 61 .

In other words, the photosensitive drum 42 A is movable between an exposing position where the LED head 411 can expose the photosensitive surface of the photosensitive drum 42 A (a position where the photosensitive drum 42 A is pinched by the rear end portions 612 B, FIG. 4( c )) and a retracted position where the photosensitive drum 42 A is retracted from the LED head 411 (a position where the photosensitive drum 42 A is positioned at the upper end portion of the arcuate portion 612 A, FIG. 4( b )).

Referring to FIG. 4( c ), an axis of light irradiated from the LED head 411 is shown as a chain line L 1 , and will be referred to as an axis of light L 1 . A diametrical center of the photosensitive drum 42 A (the rotational shaft A 1 ) is referred to as a center CP, and a position where the toner image is transferred to the sheet S from the photosensitive drum 42 A is referred to as a transfer position TP. A chain line L 2 represents a line passing through the center CP and the transfer position TP.

Further, as shown in FIG. 4( c ), the shaft-supporting portion 611 A is arranged on the axis of light L 1 . Since the rotational shaft A 1 of the photosensitive drum 42 A is moved along the arcuate portion 612 A that is one part of a circle whose center is the shaft-supporting portion 611 A, the photosensitive drum 42 A can move relative to the exposing surface 411 A in a substantially parallel manner immediately before the photosensitive surface of the photosensitive drum 42 A opposes the exposing surface 411 A. Therefore, the interference between the photosensitive drum 42 A and the exposing surface 411 A can be effectively suppressed.

Here, the transfer position TP means a point where the toner image is transferred to a transfer medium (recording sheets or an intermediate transfer belt). More specifically, the transfer position TP is a point that the photosensitive drum 42 A contacts the transfer medium. In the present embodiment, the transfer position TP is a point where the photosensitive drum 42 A contacts the sheet S (or the endless belt 43 C that conveys the sheet S).

As shown in FIG. 5 , each of the left and right walls of the process cartridge 42 is further formed with a pressing protrusion 422 . Each pressing protrusion 422 is configured to contact the supporting frame 412 of the corresponding LED unit 41 from downward when the rotational shaft A 1 moves to the rear end portion 612 B. Thus, the exposing surface 411 A of the LED head 411 can stay away from the photosensitive surface of the photosensitive drum 42 A by a prescribed distance due to the pressing protrusion 422 at the time of mounting of the photosensitive drum 42 A. Thus, the interference between the exposing surface 411 A and the photosensitive drum 42 A can be further suppressed.

With the above-described construction, the process cartridge 42 can smoothly pivotally move about the pivot shaft 421 that is supported by the shaft-supporting portion 611 A, mounting of the process cartridge 42 on the drawer 60 can be stably performed and facilitated.

Another construction for mounting the process cartridge 42 on the drawer 60 from a side opposite to the exposing surface 411 A of the LED unit 41 is also conceivable. For example, a construction without providing the pivot shaft 421 and the shaft-supporting portion 61 A in which a shaft protruding outwardly from each side wall of a process cartridge is inserted into and moved along an arcuate-shaped guide groove formed on each side wall of a casing of a drawer so that a photosensitive drum is moved to a position beneath an exposing surface of an exposing device. However, under such construction, inserting the shaft of the process cartridge into the corresponding guide grooves in a balanced manner (without causing tilting of the process cartridge in the left-to-right direction) is conceivably difficult, possibly causing the process cartridge to get stuck halfway and prevented from being fully mounted.

In contrast, with the construction of the process cartridge 42 and the drawer 60 according to the present embodiment, the process cartridge 42 can smoothly pivotally move about the shaft-supporting portion 611 A without causing any imbalance with respect to the left-to-right direction. Therefore, the process cartridge 42 can be stably and easily mounted on the drawer 60 without getting stuck.

Further, at the time of mounting the process cartridge 42 , both left and right guide rollers 412 A of the LED unit 41 can be simultaneously brought into contact with the photosensitive drum 42 A. Therefore, the guide roller 412 A can be prevented from being damaged.

Further, the in the present embodiment, the shaft-supporting portion 611 A is positioned on the axis of light L 1 . This configuration permits the photosensitive drum 42 A to move relative to the exposing surface 411 A in a substantially parallel manner immediately before the photosensitive surface of the photosensitive drum 42 A opposes the exposing surface 411 A. Therefore, interference between the photosensitive drum 42 A and the exposing surface 411 A can be effectively suppressed.

Further, the charger 60 A and the cleaning roller 60 B each having a relatively longer service life are disposed on the drawer 60 instead of the process cartridge 42 . Hence, unnecessary replacement of the charger 60 A and the cleaning roller 60 B can be prevented, while reduction in weight can be achieved for the process cartridge 42 .

Further, the process cartridges 42 and the LED units 41 are mounted on the drawer 60 which is configured to be movable relative to the main body 2 . Hence, replacement of the process cartridge 42 can be performed when the drawer 60 is pulled out from the main body 2 . Therefore, when the process cartridge 42 is detached from or mounted on the drawer 60 while pivotally moving about the shaft-supporting portion 611 A, the process cartridge 42 can be reliably prevented from interfering with the endless belt 43 C.

Although the present invention has been described with respect to the specific embodiment thereof, it will be appreciated by one skilled in the art that a variety of changes may be made without departing from the scope of the invention.

FIGS. 6 through 8 show the process cartridge 42 and a drawer 160 according to a first modification of the present embodiment. In the following description, like parts and components are designated by the same reference numerals with those of the embodiment to avoid duplicating description.

In the above embodiment, the drawer 60 is formed with the bearing groove 611 for supporting the pivot shaft 421 of the process cartridge 42 and the releasing groove 612 for guiding movement of the rotational shaft A 1 of the photosensitive drum 42 A. However, in the first modification, only a bearing portion 163 corresponding to the bearing groove 611 is provided on each of four LED units 141 .

As shown in FIGS. 6 to 8 , when mounting the process cartridge 42 , each pivot shaft 421 of the process cartridge 42 is adapted to be supported by the corresponding bearing portion 163 . With this construction, the user can realize stable pivotal movement of the process cartridge 42 simply by placing the pivot shaft 421 on the bearing portion 163 without moving the process cartridge 42 downward along the releasing groove 612 as in the above embodiment. As a result, mounting of the process cartridge 42 on the drawer 160 is further facilitated.

Note that the bearing portion 163 is not necessarily formed on each LED unit 141 , but may be formed as a member separate from the LED unit 141 .

FIGS. 9 through 11 show a process cartridge 242 and a drawer 260 according to a second modification of the embodiment.

In the second modification, each side wall 261 of drawer 260 is formed with four bearing supporting holes 264 , each process cartridge 242 is provided with a supported portion 242 G, and four pivoting members 70 are provided to pivotably movably support each process cartridge 242 about the corresponding bearing supporting holes 264 .

Specifically, each pivoting member 70 has a substantially fan-like shape and is provided with a pivot shaft 71 and a cut-out 72 .

Each bearing supporting hole 264 pivotably movably supports the pivot shaft 71 of the corresponding pivoting member 70 . The cut-out 72 is adapted to receive a supported portion 242 G of the process cartridge 242 .

With this construction, the mounted process cartridge 242 is pivotally movable relative to the drawer 260 via the pivoting member 70 . The process cartridge 242 is therefore smoothly pivotally movable about the bearing supporting hole 264 .

Further, the shaft-supporting portion 611 A may be arranged not on the axis of light L 1 but between the axis of light L 1 and the line L 2 . In this case as well, the photosensitive drum 42 A can move in a substantially parallel manner relative to the exposing surface 411 A without causing interference with the exposing surface 411 A.

Further, in the embodiment, the side walls 61 of drawer 60 are used for supporting the process cartridges 42 . However, the process cartridges 42 may be supported by left and right side walls of the main body 2 while the drawer 60 is dispensed with. In this case, although there arises a problem that the pivotally-moving process cartridge 42 may interfere with the endless belt 43 C, such interference can also be suppressed by positioning the shaft-supporting portion 611 A between the axis of light L 1 and the line L 2 , as in the embodiment.

Further, instead of the LED unit 41 , other light-emitting elements can be employed as the exposing unit. For example, a plurality of electroluminescence elements or fluorescence materials (emitting phosphor) may be arranged, and selectively illuminated based on image data. Alternatively, a plurality of light shutters configured of liquid crystal elements or PLZTs (lead zirconate titanate) and the like may be arranged relative to a single light source. Time periods for opening and closing these light shutters are selectively controlled such that light from the light source can be controlled.

Further, instead of the cleaning roller 60 B, a cleaning blade having a plate-shape may be employed as the cleaning member.

Further, the charger 60 A and the cleaning roller 60 B of the embodiment are arranged on the drawer 60 , but the charger 60 A and the cleaning roller 60 B may be provided on the process cartridge 42 , instead of the drawer 60 .

Further, the present invention may also be applicable to various image forming apparatuses other than the color printer 1 , for example, a multifunction device and a copier.

Further, the sheet S is assumed to represent thick paper, post cards and think sheets of paper as an example of recording sheets. However, OHP sheets may also be employed as the recording sheets.