Multibeam laser apparatus and image forming device using the same

A multibeam laser apparatus and an image forming device using the same. The multibeam laser beam apparatus includes a common electrode unit, a plurality of light source units to emit light using the common electrode unit, and an isolating unit to interconnect the common electrode unit and the plurality of light source units. With such configuration for example, the laser apparatus can reduce distances between the respective light source units and the number of the electrodes, and thus reduce the number of wires and legs to produce a compact chip.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2006-0088170, filed Sep. 12, 2006, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present general inventive concept relates generally to a multibeam laser apparatus and an image forming device using the same. More particularly, the present general inventive concept relates to a multibeam laser apparatus in which a common electrode is used and a dopant density of an isolating unit and varying depths of grooves are formed according to a distance from the common electrode and an image forming device to use the same.

2. Description of the Related Art

Generally, in a printer, a printing speed is decreased as resolution is increased. Accordingly, to improve the printing speed, there is a need for a high resolution printer which may use a short wavelength light source to produce a multibeam laser.

A short wavelength nitride laser apparatus, as a light source of laser printer, can produce a dot size smaller and a depth of focus better than those of a conventional infrared (IR) or red diode laser apparatus.

A multibeam nitride laser apparatus produces a multibeam laser by using an insulator substrate of sapphire (Al2O3) or the like, or a conductive substrate of GaN or the like.

In general, in the case of using the insulator substrate, a laser apparatus is configured, so that an N-type GaN layer, an N-type AlGaN clad layer, an N-type GaN optical waveguide layer, a multi-quantum well (MQW) active layer, a P-type InGaN intermediate layer, a P-type AlGaN cap layer, a P-type GaN optical waveguide layer, a P-type AlGaN clad layer and a P-type GaN contact layer are layered in sequence, and P-electrodes on the P-type GaN contact layer are connected with N-electrodes of an exposed portion of the N-type GaN layer.

Conversely, in the case of using the conductive substrate, a laser apparatus is configured, so that N-electrodes are formed on a lower end of the substrate.

Accordingly, if the multibeam is produced using the insulator substrate, the P-electrodes and the N-electrodes are located on an upper end surface of the same substrate. In this case, it is important to properly connect the inside two P-electrodes to outside electrode pads and to properly connect the N-electrodes.

Referring toFIG. 1, a conventional multibeam nitride laser apparatus is configured in a structure such that four N-electrodes11,12,13, and14and four P-electrodes15,16,17and18are formed to control four channels, respectively. The four channels are referred to as Nos.1,2,3and4from the left. To electrically isolate the channel Nos.1-2(channel No.1: arrow inFIG. 1from13to15; channel No.2: arrow inFIG. 1from11to16) and the channel Nos.3-4(channel No.3: arrow inFIG. 1from12to17; channel No.4: arrow inFIG. 1from14to18) from each other, respectively, insulating layers19and20are additionally formed on the N-type GaN layer in channel No.1and channel No.4, as illustrated. Thus, an electric current flows along a path represented by the arrows illustrated inFIG. 1.

Referring toFIG. 2, another conventional multibeam nitride laser apparatus is configured in a structure such that two N-electrodes21and22are formed at both sides of four P-electrodes24,25,26and27to allow the left N-electrode21to control channel Nos.1-2(channel No.1: from the bottom of21toward24; channel No.2: from the bottom of21toward25) and to allow the right N-electrode22to control channel Nos.3-4(channel No.3: from the bottom of22towards26; channel No.4: from the bottom of22towards27). That is, each of the N-electrodes controls two P-electrodes. To connect the inside channel Nos.2and3to the outside N-electrodes21and22, the channel Nos.2and3and the channel Nos.1and 4 are formed with the insulating layer23interposed therebetween, as illustrated inFIG. 2.

Referring toFIG. 3, another conventional multibeam nitride laser apparatus is configured in a structure such that a first N-electrode31is formed between P-electrodes30and32of channel Nos.1-2(channel No.1: from31towards30; channel No.2: from31towards32) and a second N-electrode34is formed between P-electrodes33and35of channel Nos.3-4(channel No.3: from34towards33; channel No.4: from34towards35) to allow each of the first and the second N-electrodes to control the two P-electrodes. In this case, a path length of electric current is shorter than that of the multibeam nitride laser apparatus ofFIG. 1.

The conventional multibeam nitride laser apparatuses as described above have some disadvantages as follows.

In case of the multibeam nitride laser apparatus ofFIG. 1, since there is no N-electrode between the respective channels, it can reduce distances between adjacent laser diodes. However, the multibeam nitride laser apparatus requires an additional process, which forms the two N-type GaN layers and selectively forms the insulating layers (19and20) therebetween. Also, since the four N-electrodes corresponding to the respective channels are formed, wires for controlling them are increased in number.

In case of the multibeam nitride laser apparatus ofFIG. 2, the insulating layer23, which electrically isolates channel No.1from channel No.2or electrically isolates channel No.3from channel No.4, is formed having the same height at the respective channels. Accordingly, crosstalk may occur between channel Nos.1and2and between channel Nos.3and4, respectively.

In case of the multibeam nitride laser apparatus ofFIG. 3, the N-electrodes are formed in common between channel Nos.1and2and between channel Nos.3and4, respectively. Accordingly, distances between the channels become narrowed. As a result, a problem may occur, in that it is difficult to form the laser diode structure having such channels.

SUMMARY OF THE INVENTION

The present general inventive concept provides a multibeam laser apparatus in which a common electrode is used and a dopant density of an isolating unit and varying depths of grooves (G) are formed according to a distance from the common electrode, thereby to reduce distances between respective light source units and the number of electrodes, and thus to reduce the number of wires and legs to produce a compact chip, and an image forming device to use the multibeam laser apparatus.

The foregoing and/or other aspect and utilities of the present general inventive concept may be achieved by providing a multibeam laser apparatus including a common electrode unit, a plurality of light source units to emit light using the common electrode unit, and an isolating unit to interconnect the common electrode unit and the plurality of light source units.

The isolating unit may include a semiconductor substrate in which a predetermined dopant is doped, and a doping density of the dopant may be increased according to a distance from the common electrode unit.

Also, the apparatus may further include at least one groove to isolate the plurality of light source units from each other to prevent an interference between the plurality of light source units.

The at least one groove may be connected from at least one position between upper side surfaces of the plurality of light source units to a position within the isolating unit.

A depth of the at least one groove may be increased according to a distance from the common electrode unit.

Each of the plurality of light source units may include a first semiconductor layer formed on an upper side surface of the isolating unit, an active layer formed on the first semiconductor layer, a second semiconductor layer formed on the active layer, and at least one electrode layer formed on the second semiconductor layer to be connected to a power source having an opposite polarity to a polarity of the common electrode unit.

The first semiconductor layer and the isolating unit may be formed of an N-type semiconductor, and the second semiconductor layer may be formed of a P-type semiconductor.

Alternatively, the first semiconductor layer and the isolating unit may be formed of a P-type semiconductor, and the second semiconductor layer may be formed of an N-type semiconductor.

At least one of the first and the second semiconductor layers may be a nitride semiconductor layer.

Also, the apparatus may further include an insulator substrate to come in contact with a lower side surface of the isolating unit.

According to another exemplary embodiment of the present general inventive concept, the common electrode unit may include a first common electrode formed on an area of an upper side surface of the isolating unit, and a second common electrode formed on an area spaced apart from the first common electrode in the upper side surface of the isolating unit.

Further, the plurality of light source units may include a first light source unit located between the first and the second common electrodes to use the first common electrode, and a second light source unit located between the first and the second common electrodes to use the second common electrode.

Also, the apparatus may further include a groove to isolate the first and the second light source units from each other to prevent an interference between the first and the second light source unit.

The groove may be connected from a position between upper side surfaces of the light source units to a position on the inside of the isolating unit.

According to another exemplary embodiment of the present general inventive concept, at least one of the common electrode unit and the plurality of light source units may be formed in a right angle pattern on the upper side surface of the isolating unit.

Also, the active layer, the second semiconductor layer and the electrode layer of each of the plurality of light source units may have at least one notch formed in a predetermined shape in the same position.

Alternatively, each of the first and the second common electrode may be formed in the shape of a bar on the upper side surface of the isolating unit, and each of the first and the second light source units is formed in a right angle pattern on the upper side surface of the isolating unit.

According to other exemplary embodiments of the present general inventive concept, there is provided an image forming device to use the multibeam laser apparatus as described herein.

The foregoing and/or other aspect and utilities of the present general inventive concept may be achieved by providing a multibeam laser apparatus including a common electrode unit, a plurality of light source units to emit light driven by the common electrode, an isolating unit to interconnect the common electrode unit and the plurality of light source units, where the solating unit is doped with a dopant having an increasing density along a lateral distance in a direction away from the common electrode to correspond to the respective light source units.

The foregoing and/or other aspect and utilities of the present general inventive concept may be achieved by providing a multibeam laser apparatus including a common electrode unit, a plurality of light source units to emit light driven by the common electrode, a substrate having a surface, an isolating unit on the surface of the substrate, the isolating unit to interconnect the common electrode unit and the plurality of light source units, where the plurality of light source units are isolated by one or more grooves extending into the isolating unit, and where one or more notches are formed in at least one of the light source units and in the isolating unit to permit deposition of a high reflective dielectric coating on the surface of the substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 4 and 5are views exemplifying a multibeam laser apparatus according to an exemplary embodiment of the present general inventive concept. The multibeam laser apparatus according to an exemplary embodiment of the present general inventive concept may include a common electrode unit130, a plurality of light source units260,270,280and290to emit light using the common electrode unit130, and an isolating unit220to prevent an interference between the plurality of light source units260,270,280and290.

That is, the multibeam laser apparatus according to the exemplary embodiment of the present general inventive concept may be configured so that the plurality of light source units260,270,280and290can use the common electrode unit130and can emit light when an electric power is applied to each unit by the common electrode unit130.

FIG. 4is a top plan view of the multibeam laser apparatus according to the exemplary embodiment of the present general inventive concept, andFIG. 5is a cross sectional view of the multibeam laser apparatus taken along line A-A ofFIG. 4. The multibeam laser apparatus according to an exemplary embodiment of the present general inventive concept may be a refractive index waveguide semiconductor laser having a ridge structure and a separate confinement heterostructure (SCH) structure.

Referring toFIGS. 4 and 5, the multibeam laser apparatus has the isolating unit220, which may be grown and layered on an insulator substrate210by using a lateral crystal growth technique, such as an epitaxial lateral overgrowth (ELO), for example. Other suitable layering methods may be used.

The isolating unit220may be a semiconductor substrate in which a predetermined dopant is doped. That is, the isolating unit220may be an N-type nitride semiconductor layer in which an N-type dopant, for example, silicon (Si), is doped as the predetermined dopant. In the description of the present general inventive concept, the N-type nitride semiconductor refers to a semiconductor of group III-V nitride, such as GaN, AIN, InN, etc.

The doping method may be a graded lateral doping method. Accordingly, the dopant can be doped, so that as the distance from the common electrode unit130is increased, the density of the dopant is also increased. Thus, an electric current can more smoothly flow to the plurality of light source unit260,270,280and290. For example, as illustrated inFIG. 5, dopant density D1is greater than D2, D3, and D4. The D1, D2, D3, and D4dopant densities are gradually increased from D1to D2to D3to D4according to the distance from the common electrode130. Also, for example, as illustrated inFIG. 7, the dopant density D6is greater than D5, according to the distance from common electrode330and the dopant density D8is greater than D7, according to the distanced from common electrode335.

The plurality of light source units260,270,280and290layered on the isolating unit220can be formed in a shape such that 4 mesas are disposed adjacent to one another, as illustrated inFIG. 5, for example. The light source units260,270,280and290may be separated from one another by at least one groove, for example, 3 grooves (G).

Here, the grooves G (G1, G2, and G3) can be formed to extend from positions between upper side surfaces of the light source units260,270,280and290to positions of the interior of the isolating unit220, respectively, so as to separate the light source units260,270,280and290from one another, respectively, as illustrated inFIG. 5, for example.

Also, the grooves (G) can be formed so that depths thereof are increased (or varied) according to the distance from the common electrode unit130. That is, for example, the greater the distance from the common electrode unit130, the greater the depth thereof. Thus, the groove (G) farthest from the common electrode130may have the greatest depth in relation to another groove closer to common electrode130.

With this configuration, crosstalk occurable among the light source units260,270,280and290can be reduced, minimized or prevented. Here, the crosstalk refers to an interference phenomenon of light such that light emitted from, for example, one light source unit290is detected at an adjacent light source unit280. In the case of crosstalk, an undesirable interference pattern may form between light from adjacent light sources.

Each of the plurality of light source units260,270,280and290includes a first semiconductor layer230formed on the isolating unit220, an active layer240, a second semiconductor layer250, and electrode layers110,115,120, and125connected to a power source (not illustrated) to have an opposite polarity to a polarity of the common electrode unit130.

Here, the first semiconductor layer230and the isolating unit220can be formed of an N-type semiconductor, and the second semiconductor layer250can be formed of a P-type semiconductor. Alternatively, the first semiconductor layer230and the isolating unit220may be formed of a P-type semiconductor, and the second semiconductor layer250may be formed of an N-type semiconductor.

To be more specific, each of the plurality of light source units260,270,280and290can be configured so that an N-type AlGaN clad layer and an N-type GaN optical waveguide layer form an N-type nitride semiconductor layer as the first semiconductor layer230; an active layer240of (In, Ga)N:GaN multi-quantum well (MQW) structure; a P-type InGaN intermediate layer, a P-type AlGaN cap layer, a P-type GaN optical waveguide layer, a P-type AlGaN clad layer and a P-type GaN contact layer form a P-type nitride semiconductor layer as the second semiconductor layer250; and P type-electrode layers110,115,120and125are layered thereon in turn, for example, as illustrated inFIG. 5.

Here, the second semiconductor layer250not only acts to prevent ‘In’ from being broken away from the active layer240and deteriorated, but also to prevent (or to reduce or to minimize) overflow of electrons from the active layer240.

At least one of the common electrode unit130and the plurality of light source units260,270,280and290can be formed in a right angle pattern on the upper side surface of the isolating unit220, respectively, as illustrated inFIG. 4, for example.

On the other hand, the common electrode unit130layered on one side of the upper side surface of the isolating unit220can be formed of a metal. The plurality of light source units260,270,280and290can be connected to the common electrode unit130, and can emit light when an electric power is applied thereto. Thus, the multibeam laser apparatus can reduce the number of separate electrodes and thus the number of wires and legs in a chip needed to emit laser light from a multibeam laser apparatus.

Ridges135,140,145, and150can be formed in the plurality of light source units260,270,280and290, respectively. That is, the ridges135,140,145, and150can radiate light emitted from the active layer240. The ridges can be located at low defect areas between electric charges propagated to the upper layers from seed crystals that may be grown using a lateral growth method as described below.

Notches155,160and170can be formed in a predetermined shape at the same position as the position of the active layer240, the second semiconductor layer250, and the electrode layers110,115,120, and125of each of the plurality of light source units260,270,280and290, respectively, so as to provide a space for deposition of a high reflective dielectric coating. That is, when a dielectric may be coated on a surface of the substrate, the notches155,160and170can penetrate to a depth to indirectly absorb and reflect light of specified wavelength.

Hereinafter, a fabrication method of the multibeam laser apparatus according to the exemplary embodiment of the present general inventive concept will be described. At first, by using a metal organic chemical vapor deposition (MOCVD) method, an isolating unit220is grown on an insulator substrate210, a surface of which is planarized by a thermal cleansing method or the like.

Here, the isolating unit220refers to a nitride semiconductor layer formed using a lateral crystal growth technique, for example. A doping method of an N-type dopant can use a graded lateral doping method. In other words, the concentration or density of the dopant (e.g., N-type or other suitable dopant) may be gradually increased as the lateral distance (along the isolating unit220) from the common electrode130is increased, for example. Other gradual changes in the dopant concentration or density may be provided as the lateral distance (along the isolating unit220) from the common electrode130is increased. For example, the concentration or density of the dopant (e.g., N-type dopant or P-type dopant) may gradually (or stepwise) increase (or gradually vary or gradually decrease, if so desired) as the lateral distance (along the isolating unit220) from the common electrode30is increased.

On the isolating unit220, a plurality of light source units260,270,280, and290can be formed. The light source units can include an N-type nitride semiconductor layer230that can be formed by the MOCVD method on the isolating unit220. To be more specific, an N-type nitride semiconductor layer230, an active layer240of MQW structure, and a P-type nitride semiconductor layer250can be grown in turn on the isolating unit220. Also, as illustrated inFIGS. 4 and 5, P-type electrodes110,115,120, and125can be formed on the second semiconductor layer250

In the growth of the nitride type semiconductor layers230or250(or both), materials of Ga, Al, In, and N, such as trimethylgallium (TMG), trimethyl aluminum (TMA), trimethyl indium (TMI), and NH3can be used, respectively. As an N-type dopant and a P-type dopant, Si and Mg can be used, respectively.

Next, ridges135,140,145, and150can be formed by selectively etching the nitride type semiconductor layers down to a depth of the P-type nitride semiconductor layer250by a reactive ion etching (RIE) method, for example, as illustrated inFIG. 5.

After that, the nitride type semiconductor layers can be etched to form the grooves (G) using the P-type electrode layers as a mask up to a portion of the isolating unit220by an RIE method until the desired depth is obtained, for example. As a result, the light source units260,270,280, and290can be formed in such a shape so that 4 mesas can be disposed adjacent to one another and at the same time, grooves (G) can be formed to divide the light source units260,270,280, and290from one another, as illustrated inFIG. 5, for example. At this time, the grooves (G) can be formed so that their corresponding depths can be increased in proportion to a distance from the common electrode unit130to be described in further detail below, also as illustrated inFIG. 5, for example.

The common electrode unit130can be formed on one side of the isolating unit220by the RIE method as described above. Here, for example, the common electrode unit130can have an N-polarity, and can be used as a common electrode for the plurality of light source units260,270,280, and290, with the layers having the appropriate polarities sufficient to emit the desired multibeam laser light.

According to this, the number of electrodes can be reduced with the use of the common electrode unit130, and the crosstalk occurable among the respective light source units260,270,280, and290can be reduced, minimized or prevented with the varying dopant densities of the isolating unit220and the varying depths of the grooves (G) formed to be different according to the distance from the common electrode unit130.

FIGS. 6 and 7are views exemplifying a multibeam laser apparatus according to another exemplary embodiment of the present general inventive concept.

FIG. 6is a top plan view of a multibeam laser apparatus, andFIG. 7is a cross-sectional view of the multibeam laser apparatus taken along line B-B ofFIG. 6.

Referring toFIGS. 6 and 7, the multibeam laser apparatus includes a first common electrode330formed on a portion area of an upper side surface of an isolating unit420, a second common electrode335formed on a portion of the upper side surface of the isolating unit420spaced apart from the first common electrode330, and a first light source unit460and470and a second light source unit480and490located between the first and the second common electrodes. The material elements (and/or density or concentrations) used in forming the various layers illustrated inFIGS. 6 and 7are the same as those of the corresponding multibeam laser apparatus explained with reference toFIGS. 3 and 4. Thus, a detailed description thereof will be for brevity. However, the description of the materials used and their concentrations or densities with respect to the embodiments ofFIGS. 4 and 5may be applied to the embodiments of FIGS.6and7—with the exception that the density or concentration of the dopant in insulating unit420can be gradually increased toward the illustrated central groove ofFIGS. 6 and 7, for example.

In the multibeam laser apparatus according to another exemplary embodiment of the present general inventive concept, a central groove (G), which divides the first light source unit460and470and the second light source unit480and490from each other, can be formed to have a depth extending from a position between adjacent upper surfaces of the first and the second light source units down to a position of the interior of an insulator substrate410. Accordingly, the groove can reduce an interference between the first light source unit460and470and the second light source unit480and490.

Also, the first light source unit460and470can be connected with and driven by the first common electrode330formed on a portion area of the upper side surface of the isolating unit420. Further, the isolating unit420can be formed so that as the lateral distance from the first common electrode330is increased, the dopant density thereof is also increased. With this configuration, an electric current can smoothly flow from the common electrode330toward the P-electrodes310and315.

In the same manner, the second light source unit480and490can be connected with and driven by the second common electrode335formed on a portion area of the upper side surface of the isolating unit420. Further, the isolating unit420can be formed so that as the lateral distance from the second common electrode335is increased, the dopant density thereof is also increased. With this configuration, an electric current can smoothly flow from the common electrode335toward the P-electrodes320and325.

Ridges355,360,365and370can be formed in light sources460,470,480and490of the first and the second light source units, respectively. That is, the ridges355,360,365and370, which radiate light emitted from an active layer440, can be located at low defect areas between electric charges propagated to upper layers from seed crystals that can be grown using a lateral growth technique.

Also, notches340and345can be formed to provide a space to permit deposition of a high reflective dielectric coating. That is, when a dielectric is coated on a surface of the substrate, the notches340and345can penetrate to a depth sufficient to indirectly absorb and reflect light of specified wavelength.

The first and second light source units460,470,480and490can be formed in a right angle pattern on the upper side surface of the isolating unit420, respectively, as illustrated inFIGS. 6 and 7, for example.

In exemplary embodiments, the multibeam laser apparatus may include grooves G1and G3which extend to varying depths into the isolating unit420to isolate the first and second light source units460,470,480, and490. The multibeam laser apparatus may also include a first common electrode330formed on an area of an upper surface of the isolating unit420and a second common electrode335formed on another area of the upper surface of the isolating unit420.

FIGS. 8 and 9are views exemplifying an image forming device using the multibeam laser apparatus according to exemplary embodiments of the present general inventive concept.

Referring toFIG. 8, the image forming device500using the multibeam laser apparatus can include a laser scanning unit (LSU)510and a printing unit520.

The LSU510can emit and can scan a plurality of light beams on a surface of a photoconductive drum and thus can form an electrostatic latent image corresponding to an image to be printed on the surface of the photoconductive drum.

Also, the LSU510can include a multibeam laser apparatus. The multibeam laser apparatus can be formed so that a plurality of light sources are divided by at least one groove (G) (e.g., 2 or more grooves, 3 or more grooves, etc.), and as the lateral distance from a common electrode unit is increased, the dopant density of an isolating unit is increased. Also, as the lateral distance from a common electrode is increased, the depth of the grooves (G) is increased. Since such a multibeam laser apparatus can be the same as the multibeam laser apparatus of the exemplary embodiments explained with reference toFIGS. 4 through 7, a detailed description thereof will be omitted for brevity.

The printing unit520can execute a series of image forming process operations which can include a charge operation, an exposure operation, a development operation, a transfer operation, a fixing operating and a discharge operation as needed to develop the electrostatic latent image formed on the photoconductive drum by the LSU510into a developer image and to transfer and to fix the developer image on a printing paper (or other suitable medium) to form a desired image.

Referring toFIG. 9, a construction of the image forming device ofFIG. 8is illustrated in further detail pursuant to an embodiment of the present general inventive concept. The image forming device can include the LSU510and the printing unit520. The LSU510can be provided with a multibeam laser apparatus610having the same structure as that of the multibeam laser apparatus of the exemplary embodiments explained with reference toFIGS. 4 through 7, a polygon mirror620, a focusing unit630, and a light receiving unit640. The printing unit520can be provided with a photoconductive drum650, a charging unit660, a developing unit670, a transferring roller680, and a fixing unit690.

Light emitted from the multibeam laser apparatus610of the LSU510can arrive as parallel beams of or as a convergent beam of light which are/is parallel to a main scanning direction and a sub-scanning direction while passing through a lens unit (not illustrated).

After passing through the lens unit (not illustrated), the light becomes incident on the polygon mirror620. And then, the incident light can be reflected in a predetermined angle by the polygon mirror620, which can be rotated at a high speed, and can be emitted toward the focusing unit630.

The focusing unit630can include a scanning system lens, which can be made of a toric lens and a focusing lens. The focusing unit630can focus and can scan the incident light onto the photoconductive drum650of the printing unit520. The photoconductive drum650has a surface area that is of an effective scanning width section (not illustrated) on which an electrostatic latent image can be formed by the scanned light from the focusing unit630. The LSU510can be equipped with the light receiving unit640to detect a horizontal synchronizing signal H13sync for regularly synchronizing the effective scanning width section of the photoconductive drum650with that of the light from the focusing unit630.

Here, the horizontal synchronizing signal H13sync is a signal produced by the laser scanning unit510used to form the electrostatic latent image on the photoconductive drum650.

The printing unit520can form an image on a printing paper (or other suitable medium) at a high speed. For this, the printing unit520can be provided with a charging unit660to charge (and/or discharge as needed) the photoconductive drum650with a predetermined electric charge to form (or erase) an electrostatic latent image, a developing unit670to develop the electrostatic latent image formed on the photoconductive drum650by the LSU510as described above with a developer, a transferring roller680to transfer the developed image onto the printing paper (or other suitable medium) while rotating in engagement with the photoconductive drum650, and a fixing unit690to fuse (or fix) the image transferred on the printing paper (or other suitable medium) with heat and/or pressure.

The image forming device constructed as described above can use the multibeam laser apparatus so that it can improve the printing speed and/or resolution.

As apparent from the foregoing description, according to the exemplary embodiments of the present general inventive concept, the multibeam laser apparatus and the image forming device to use the same utilize a the common electrode. Accordingly, the multibeam laser apparatus according to the exemplary embodiments of the present general inventive concept and the image forming device to use the same can reduce the distances between the respective light source units and the number of electrodes, and thus reduce the number of wires and legs to produce a more compact chip.

Further, the multibeam laser apparatus according to the exemplary embodiments of the present general inventive concept and the image forming device to use the same can be configured so that the dopant density of the isolating unit and the depths of the grooves (G) are formed to be different according to the distance from the common electrode. Accordingly, the crosstalk among the light source units can be reduced, minimized or prevented.

Also, the image forming device according to the exemplary embodiments of the present general inventive concept can use the multibeam laser apparatus so that it can improve the printing speed and the printing resolution. An image forming apparatus (or device) may include any one of the above-noted the multibeam laser apparatuses described herein.