JP2008276270A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing an installation area, regardless of the areas of recording mediums, while having a plurality of image forming parts. <P>SOLUTION: Process units 33 for respective colors are vertically arranged parallel to each other in a casing 2. A sheet feed section 3 and a sheet ejection section 5 are disposed higher than the process units 33. Sheets 31, before subjected to color image formation, are vertically held in the sheet feed holder part 28 of the sheet feed section 3, and the sheet 31 after subjected to the color image formation are held vertically in the sheet ejection holder part 64 of the sheet ejection section 5. This makes it possible to reduce the installation area, regardless of the areas of the sheets 31, while having the plurality of process units 33. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a color laser printer.

The color laser printer includes four photosensitive drums corresponding to yellow, magenta, cyan, and black colors. The electrostatic latent image formed on each photosensitive drum is developed with each color, and a toner image corresponding to each color is developed. A tandem color laser printer is known that forms on a photosensitive drum and then transfers each toner image onto a sheet.
In such a tandem color laser printer, four image forming units including a photosensitive drum and a developing device are arranged at intervals in the horizontal direction, and the paper is conveyed along the horizontal direction. The direct tandem type that directly transfers the image of each color to the paper by sequentially contacting the photosensitive drum of each image forming unit, or an intermediate transfer belt in the horizontal direction so as to face each image forming unit, An intermediate transfer tandem type has been proposed in which an image of each color is once transferred to an intermediate transfer belt and then transferred from the intermediate transfer belt to a sheet at a time.

However, when the four image forming units are arranged in parallel in the horizontal direction, the installation area is greatly increased as compared with a monochrome laser printer having one image forming unit.
Therefore, for example, four independent image forming stations PY, PM, PC, and PK having a photosensitive drum, a developing device, a cleaning device, and the like are vertically arranged along the ascending orbit side of the transfer belt having a vertical rotation orbit. Is formed in a row, and the paper adsorbed on the transfer belt is conveyed to the stations P to PK, and the toner images of the respective colors formed at the stations P to PK are multiplex-transferred onto the paper to obtain a full color image. An apparatus has been proposed (see, for example, Patent Document 1).
JP 2001-109325 A

However, in the image forming apparatus described in Patent Document 1, since the image forming stations are arranged so as to overlap in the vertical direction, the installation area can be reduced as compared with the case where the image forming stations are arranged in the horizontal direction. .
However, in this image forming apparatus, the sheets are set along the horizontal direction so that the sheets can be stacked along the vertical direction. Therefore, in order to reduce the installation area, there is a limit in relation to the area of the paper.

  An object of the present invention is to provide an image forming apparatus capable of reducing the installation area regardless of the area of the recording medium while having a plurality of image forming units.

  In order to achieve the above object, the invention according to claim 1 is a casing, a plurality of image forming units that are arranged so as to overlap in the vertical direction in the casing and that form images of different colors, and the image forming unit. A supply unit that is arranged above the image forming unit, holds the recording medium along the vertical direction, and supplies the held recording medium to the image forming unit side, and is arranged above the image forming unit, A discharge unit that holds an image formed in the image forming unit and discharged from the image forming unit side in a vertical direction; a stacking direction in which the recording medium is stacked in the supply unit and the discharge unit; The width direction moving means for moving the casing only in the width direction orthogonal to the vertical direction and at least a part of the image forming unit are covered or opened, and each of the images A second cover for attaching and detaching the forming section to and from the casing, and each of the image forming sections is arranged along the same direction as a stacking direction in which recording media are stacked in the supply section and the discharge section. It is characterized by being attached to and detached from the casing.

According to such a configuration, the recording medium before image formation is held above the image forming unit and is held along the vertical direction in the supply unit, and the recording medium after image formation is above the image forming unit. Thus, the discharge portion is held along the vertical direction. Therefore, the installation area can be reduced regardless of the area of the recording medium while having a plurality of image forming units.
Further, according to such a configuration, each image forming unit can be attached to and detached from the casing along the same direction as the stacking direction in which the recording media are stacked. Therefore, each image forming unit can be easily attached to and detached from the casing without interfering with the supply unit and the discharge unit disposed above the image forming unit.

In this configuration, in the casing, the width direction of the recording medium needs to be a minimum in the width direction, while the stacking direction can be formed significantly smaller than the width direction. If the casing is formed in such a manner, the casing may fall over when the casing is moved in the stacking direction.
However, in this configuration, since the width direction moving means moves the casing only in the width direction, the movement of the casing in the stacking direction is restricted and the casing is prevented from falling while ensuring the mobility of the casing. Can do. Further, when the image forming apparatus of the present invention is installed in a narrow gap, the image forming apparatus can be smoothly moved. Furthermore, each image forming unit is attached to and detached from the casing in the same direction as the stacking direction in which the recording media are stacked in the supply unit and the discharge unit. Can be prevented well.

The invention described in claim 2 is characterized in that, in the invention described in claim 1, position changing means is provided which makes it possible to change the position of the casing along the vertical direction.
According to such a configuration, the vertical position of the casing can be changed by the position changing means. Therefore, the optimal installation can be ensured by adjusting the vertical position of the image forming apparatus corresponding to the installation environment.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the invention is provided so as to be swingable with respect to the casing, and at least a part of the supply part and the discharge part is covered or opened. The second cover is provided so as to be swingable with respect to the casing, and the first cover is disposed above the second cover.

According to such a configuration, the first cover and the second cover can be opened and closed independently without interfering with each other. Therefore, at least a part of the supply unit and the discharge unit can be opened and covered by the opening / closing operation of the first cover, and at least a part of the image forming unit can be independently opened / closed by the opening / closing operation of the second cover. Can be opened and coated.
According to a fourth aspect of the present invention, in the third aspect of the present invention, the first cover and the second cover are arranged on the same side surface of the casing.

According to such a configuration, since the first cover and the second cover are arranged on the same side surface of the casing, the opening / closing operation of the first cover and the opening / closing operation of the second cover can be operated from the same side. . Therefore, operability can be improved.
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a width perpendicular to a stacking direction and a vertical direction in which recording media are stacked in the supply unit and the discharge unit. A second shaft provided in the casing along a direction is provided, and the second cover is provided to be swingable with respect to the casing with the second shaft as a fulcrum.

  According to such a configuration, at least a part of the image forming unit can be opened by opening the second cover, and the image forming unit can be covered by closing the second cover. Therefore, the image forming unit can be attached to and detached from the casing by the opening and closing operation of the second cover. The second axis is provided along the width direction, and the second cover is swung around the second axis as a fulcrum. Therefore, the second axis is provided along the stacking direction, and the second axis is used as a fulcrum. As compared with the case where the second cover is swung, at least a part of the image forming unit can be opened more widely by the opening operation of the second cover.

  According to a sixth aspect of the present invention, in the invention according to any one of the third to fifth aspects, a width perpendicular to a stacking direction and a vertical direction in which recording media are stacked in the supply unit and the discharge unit. A first shaft provided in the casing along a direction is provided, and the first cover is provided to be swingable with respect to the casing with the first shaft as a fulcrum.

  According to such a configuration, if the first cover is opened, at least a part of the supply unit and the discharge unit can be opened, and if the first cover is closed, the supply unit and the discharge unit are covered. Can do. Therefore, the recording medium can be taken in and out of the supply unit and the discharge unit by opening and closing the first cover. And since the 1st axis is provided along the width direction and the 1st cover is rocked about the 1st axis as a fulcrum, the 1st axis is provided along the lamination direction, and the 1st axis is used as a fulcrum. As compared with the case of swinging the first cover, at least a part of the supply unit and the discharge unit can be opened more widely by the opening operation of the first cover.

The invention according to claim 7 is the invention according to claim 5 or 6, wherein the side surface of the casing opposite to the side surface on which the first cover or the second cover is disposed has a flat shape. It is characterized by being formed.
According to such a configuration, in the casing, the side surface opposite to the side surface on which the first cover or the second cover is disposed is formed in a flat shape. Therefore, by disposing the opposite side surface on the wall side, it can be installed without a gap with respect to the wall, and further space saving can be achieved.

The invention according to claim 8 is characterized in that, in the invention according to any one of claims 1 to 7, an operation panel is provided on an upper surface of the casing.
According to such a configuration, the operation panel is provided on the upper surface of the casing. Therefore, even if it is installed in a narrow space, the operation panel can be easily operated from above.
The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the casing is disposed above the image forming unit and below the discharge unit in the casing. The image forming unit includes a fixing unit for fixing the image formed on the recording medium.

According to such a configuration, the fixing unit is disposed above the image forming unit and below the discharge unit in the casing. Therefore, it is possible to reduce the influence of the heat generated from the fixing unit on the image forming unit while reducing the size of the apparatus.
According to a tenth aspect of the present invention, in the invention according to any one of the first to ninth aspects, each of the image forming units includes a photoconductor on which an electrostatic latent image is formed, and each of the image forming units. The image forming unit and the exposure unit are alternately arranged along the vertical direction. The exposure unit is provided corresponding to the exposure unit for exposing the photoconductor.

According to such a configuration, the image forming units and the exposure units are alternately arranged along the vertical direction. Therefore, further slimming of the apparatus can be achieved.
An eleventh aspect of the invention is characterized in that, in the invention according to any one of the first to tenth aspects, the supply section and the discharge section are arranged to face each other with an interval in the horizontal direction. .

According to such a configuration, the supply unit and the discharge unit are disposed to face each other with an interval in the horizontal direction above the image forming unit. Therefore, the size in the vertical direction can be made compact, and the upper surface of the casing can be made flat.
According to a twelfth aspect of the present invention, in the invention according to any one of the first to eleventh aspects, the recording medium supplied from the supply unit is conveyed from the upper side to the lower side, and the lowest image is displayed. It is characterized by having a transport path for transporting from the lower side to the upper side toward the discharge part after turning the circumference of the forming part.

According to such a configuration, the recording medium is supplied from the supply unit along the conveyance path, passes through all the image forming units, and is then discharged to the discharge unit. Therefore, the recording medium can be efficiently conveyed to form an image while the apparatus is slimmed down.
According to a thirteenth aspect of the present invention, in the invention according to any one of the first to twelfth aspects, the recording medium is arranged along the vertical direction so as to face each of the image forming portions, and for conveying a recording medium. It is characterized by having a transport unit.

According to such a configuration, the recording medium can be transported in the transport section so as to sequentially face each image forming section. Therefore, the image forming apparatus can be provided as a direct tandem type image forming apparatus.
The invention described in claim 14 is characterized in that, in the invention described in claim 13, the transport section is disposed to face the discharge section in the vertical direction.

According to such a structure, a conveyance part is opposingly arranged by the discharge part in an up-down direction. Therefore, after the image forming unit forms an image on the recording medium, the recording medium on which the image is formed can be discharged upward as it is. As a result, the image can be discharged to the discharge unit without deteriorating the image quality of the recording medium.
According to a fifteenth aspect of the present invention, in the invention according to any one of the first to twelfth aspects, the image forming unit is arranged along a vertical direction so as to face each of the image forming units. An image is transferred in an overlapping manner, and an intermediate transfer portion for transferring the overlapped image onto a recording medium is provided.

According to such a configuration, the images from the respective image forming units are transferred and transferred onto the intermediate transfer unit, and the transferred images are transferred to the recording medium at the intermediate transfer unit. Therefore, it can be provided as an intermediate transfer tandem type image forming apparatus.
The invention described in claim 16 is characterized in that, in the invention described in claim 15, the intermediate transfer portion is disposed to face the discharge portion in the vertical direction.

According to such a configuration, the intermediate transfer portion is disposed to face the discharge portion in the vertical direction. Therefore, after the image is transferred to the recording medium in the intermediate transfer unit, the recording medium on which the image is transferred can be discharged upward as it is. As a result, the image can be discharged to the discharge unit without deteriorating the image quality of the recording medium.
The invention described in claim 17 is the invention according to any one of claims 1 to 16, wherein each of the image forming portions has a curved shape along a side surface of the casing that is opened and closed by the second cover. It is characterized by being attached to and detached from the casing along the attachment / detachment path.

  According to such a configuration, each image forming unit is attached to and detached from the casing along a curved attachment / detachment path along the side surface of the casing. Therefore, a space that is slightly wider than the width in the direction perpendicular to the attachment / detachment path of each image forming unit attached / detached along the attachment / detachment path outside the casing is secured around the casing. As a result, the space occupied by the image forming apparatus can be reduced. As a result, the degree of freedom of the installation place of the image forming apparatus can be increased.

According to the first aspect of the present invention, it is possible to reduce the installation area regardless of the area of the recording medium while having a plurality of image forming units.
In addition, each image forming unit can be easily attached to and detached from the casing without interfering with the supply unit and the discharge unit disposed above the image forming unit.
Furthermore, it is possible to prevent the casing from falling over by restricting the movement of the casing in the stacking direction while securing the mobility of the casing.

According to the second aspect of the present invention, it is possible to ensure optimal installation by adjusting the vertical position of the image forming apparatus corresponding to the installation environment.
According to the invention described in claim 3, at least a part of the supply unit and the discharge unit can be opened and covered by the opening / closing operation of the first cover, and independently of this, the opening / closing operation of the second cover Thus, at least a part of the image forming unit can be opened and covered.

According to the invention described in claim 4, operability can be improved.
According to the fifth aspect of the present invention, at least a part of the image forming unit can be more widely opened by the opening operation of the second cover.
According to the sixth aspect of the present invention, at least a part of the supply unit and the discharge unit can be opened more widely by the opening operation of the first cover.

According to the seventh aspect of the present invention, further space saving can be achieved by arranging the opposite side surface on the wall side.
According to the eighth aspect of the invention, the operation panel can be easily operated from above even when installed in a narrow space.
According to the ninth aspect of the present invention, it is possible to reduce the influence of heat generated from the fixing unit on the image forming unit while reducing the size of the apparatus.

According to the invention of the tenth aspect, the device can be further slimmed.
According to the eleventh aspect of the invention, the size in the vertical direction can be made compact, and the upper surface of the casing can be made flat.
According to the twelfth aspect of the present invention, it is possible to efficiently convey the recording medium and form an image while reducing the size of the apparatus.

According to the invention described in claim 13, it can be provided as a direct tandem type image forming apparatus.
According to the fourteenth aspect of the present invention, the image can be discharged to the discharge unit without deteriorating the image quality of the recording medium.
According to the fifteenth aspect of the present invention, an intermediate transfer tandem type image forming apparatus can be provided.

According to the sixteenth aspect of the present invention, the image can be discharged to the discharge portion without deteriorating the image quality of the recording medium.
According to the seventeenth aspect of the present invention, the degree of freedom of the installation place of the image forming apparatus can be increased.

(First embodiment)
FIG. 1 is a front perspective view showing a first embodiment of a color laser printer as an image forming apparatus of the present invention, and FIG. 2 is a main part showing a height adjusting mechanism of the color laser printer shown in FIG. FIG. 3 is a side sectional view of the color laser printer shown in FIG. 1, and FIG. 4 is an enlarged side sectional view of main parts of the process unit and the scanner unit shown in FIG.
A. In FIG. 1, a color laser printer 1 is a vertical-type direct tandem type color laser printer, which includes a casing 2, a paper feed unit 3 as a supply unit provided in the casing 2, and an engine. And a paper discharge section 5 as a discharge section.

In the following description, the front side where the upper cover 11 and the lower cover 12 in FIG. 3 are provided is the front side, and the back side opposite to the front side is the rear side.
B. Casing The casing 2 is made of hard resin and is formed in a box shape integrally including a front surface 6, a rear surface 7, a top surface 8, a bottom surface 9, and both side surfaces 10, as shown in FIG. The casing 2 does not have a protruding portion, extends in the vertical direction, is thin in the front-rear direction, is thick in the width direction (the vertical direction and the direction orthogonal to the front-rear direction, the same shall apply hereinafter), and is formed in a stable vertically long and thin shape. . Moreover, while the back surface 7 is formed in a flat shape, the upper part of the front surface 6 is inclined in a curved shape in a direction approaching the back surface 7 as it goes upward.

Further, an upper cover 11 as a first cover and a lower cover 12 as a second cover are provided on the front surface 6 of the casing 2.
The upper cover 11 is disposed in the upper part of the front surface 6 so as to face the paper discharge unit 5 in the front-rear direction. The upper cover 11 has a substantially rectangular flat plate shape in a front view that is inclined in a curved shape in a direction approaching the back surface 7 as it goes upward, and is formed of a hard resin. An upper opening / closing shaft 13 as a first shaft extending along the width direction is rotatably supported on both side surfaces 10 of the casing 2 at the lower end portion of the upper cover 11 on the front surface of the casing 2.

  The lower end of the upper cover 11 is attached to the upper opening / closing shaft 13, whereby the upper end moves in the front-rear direction with the upper opening / closing shaft 13 at the lower end as a fulcrum with respect to the front surface 6 of the casing 2. So that it is swung. Then, if the upper end portion of the upper cover 11 is moved forward with the lower end portion as a fulcrum, the discharge unit 5 is released from the upper cover 11 by the opening operation of the upper cover 11 as shown by the dotted line in FIG. The Further, if the upper end of the opened upper cover 11 is moved rearward with the lower end serving as a fulcrum, as shown by the solid line in FIG. 11 is covered.

  The lower cover 12 is a lower portion of the front surface 6 and is disposed below the upper cover 11 so as to face the engine unit 4 in the front-rear direction. The lower cover 12 has a substantially rectangular flat plate shape when viewed from the front, and is formed of a hard resin. A lower opening / closing shaft 14 as a second shaft extending along the width direction is rotatably supported on both side surfaces 10 of the casing 2 at the lower end portion of the lower cover 12 on the front surface 6 of the casing 2.

  The lower cover 12 has a lower end attached to the lower opening / closing shaft 14, whereby the upper end moves in the front-rear direction with the upper opening / closing shaft 14 at the lower end as a fulcrum with respect to the front surface 6 of the casing 2. To be rocked. When the upper end portion of the lower cover 12 is moved forward with the lower end portion as a fulcrum, the engine portion 4 is released from the lower cover 12 by the opening operation of the lower cover 12 as shown by the dotted line in FIG. . Further, if the upper end portion of the opened lower cover 12 is moved rearward with the lower end portion as a fulcrum, the engine unit 4 is moved by the closing operation of the lower cover 12 as shown by the solid line in FIG. Is covered.

The lower cover 12 is fixed with a transfer section 35 described later, and moves together with the lower cover 12 by the opening and closing operation of the lower cover 12 (see FIG. 3).
An operation panel 15 for operating the color laser printer 1 is provided on the upper surface 8 of the casing 2. The operation panel 15 includes a liquid crystal panel on which the operating state of the color laser printer 1 is displayed, buttons that can be operated by a user who sets various conditions, and the like.

The casing 2 is attached to the gantry 16. The gantry unit 16 includes a support plate 17, a caster 18 as a width direction moving unit, a support rod 19, and a height adjusting mechanism unit 20 (see FIG. 2) as a position changing unit.
The support plate 17 has a substantially rectangular flat plate shape in plan view that is slightly larger than the bottom surface 9 of the casing 2, and a caster 18 is provided on the lower surface of the support plate 17.

The caster 18 includes a roller that can roll, and is provided in a state in which the rolling direction of the roller is fixed so that the casing 2 moves only in the width direction at the four corners of the support plate 17.
The support rods 19 are erected from four corners on the upper surface of the support plate 17. As shown in FIG. 2, each support rod 19 has a plurality of locking holes 22 that are locked with locking claws 26, which will be described later, of the height adjusting mechanism portion 20. Has been. In addition, at each of the four corners in the casing 2, insertion cylinder portions 21 that receive the support rods 19 are provided corresponding to the support rods 19 along the vertical direction. It is slidably inserted in.

The height adjusting mechanism portion 20 is provided in the vicinity of the bottom surface 9 in the casing 2 so as to correspond to at least one of the four support rods 19, and includes an engagement lever 23 and a tension spring 24. Yes.
The engaging lever 23 is substantially Z-shaped in a side view, and an engaging claw 26 that protrudes in one direction is formed at one end of the engaging lever 23, and an engaging claw 26 is formed at the other end. A grip portion 25 extending in the other direction opposite to the pawl 26 is formed. In the engaging lever 23, in the vicinity of the bottom surface 9 in the casing 2, the locking claw 26 opposes the locking hole 22 of the support rod 19 in the casing 2, and the gripping portion 25 extends from the bottom surface 9 of the casing 2. It arrange | positions so that it may expose outside, and the center part is being fixed to the support shaft 27 provided in the casing 2 so that rotation is possible.

One end of the tension spring 24 is fixed to a portion of the engagement lever 23 between the center portion and the grip portion 25, and the other end is fixed to the inner surface of the casing 2 facing the portion.
The engaging lever 23 is always urged by the tensile force of the tension spring 24 so as to rotate in the direction in which the locking claw 26 is inserted into the locking hole 22 of the support rod 19. Further, when the gripping portion 25 of the engagement lever 23 is pressed against the tensile force of the tension spring 24, the engagement lever 23 uses the support shaft 27 as a fulcrum and the engagement claw 26 engages with the engagement hole of the support rod 19. Rotate in a direction away from 22.

  When the holding portion 25 is pressed and the locking claw 26 is separated from the locking hole 22, the support rod 19 is slidable with respect to the insertion tube portion 21. On the other hand, the position can be changed along the vertical direction. In that state, the support rod 19 is slid in the vertical direction with respect to the insertion tube portion 21, the vertical height of the casing 2 is adjusted as appropriate, and the locking hole 22 corresponding to the optimum height is It is made to oppose to the latching claw 26. Thereafter, when the pressing of the gripping portion 25 is released, the locking claw 26 is inserted into the locking hole 22 by the tensile force of the tension spring 24, whereby the casing 2 is adjusted to the optimum vertical height. Thus, it is supported by the gantry 16.

Further, the casing 2 supported by the gantry 15 can be moved only in the width direction by each caster 18.
C. As shown in FIG. 3, the sheet feeding unit 3 is disposed in the casing 2 on the upper rear side with respect to each process unit 33 (described later) of the engine unit 4. The paper feed unit 3 includes a paper feed holder unit 28 that holds a paper 31 as a recording medium, a paper pressing plate 29 disposed in the paper feed holder unit 28, and a front side of the lower end of the paper feed holder unit 28. The paper feed roller 30 is provided.

The paper feed holder portion 28 is composed of a cassette with a bottomed frame that can accommodate the paper 31 whose front side is opened. The paper feed holder portion 28 is detachably attached to the casing 2 along the vertical direction from the upper surface 8 thereof.
The paper pressing plate 29 is provided from the middle in the up-down direction to the lower end in the paper feed holder portion 28. The sheet pressing plate 29 has an upper end portion rotatably supported on the rear surface of the paper feed holder portion 28, and a rear surface of the lower end portion is urged forward by a pressing spring 32.

The paper feed roller 30 is disposed opposite to the lower end portion of the paper pressing plate 29 biased by the pressing spring 32.
In the sheet feeding unit 3, the sheet 31 is held on the sheet pressing plate 29 in the sheet feeding holder unit 28 along the vertical direction, and runs in the front-rear direction against the urging force of the pressing spring 32. Are stacked. The uppermost (first) paper 31 stacked on the paper pressing plate 29 is pressed so as to come into contact with the paper feed roller 30 by the urging force of the spring 25, and by rotation of the paper feed roller 30, for each sheet, Paper is fed toward the engine unit 4.
D. Engine Unit The engine unit 4 includes a process unit 33 as an image forming unit, a scanner unit 34 as an exposure unit, a transfer unit 35, a conveyance path 36, and a fixing unit 37.
a. Process Unit The process unit 33 is disposed below the paper feed unit 3 and the paper discharge unit 5 in the casing 2, and a plurality (four) of different colors are provided, and is detachably attached to the casing 2. ing. More specifically, the process unit 33 includes four process units 33, which are a yellow process unit 33Y, a magenta process unit 33M, a cyan process unit 33C, and a black process unit 33K. These are arranged in parallel at intervals from each other so as to overlap in the vertical direction from the bottom to the top.

Each process unit 33 is opened from the lower cover 12 by the opening operation of the lower cover 12 as indicated by a dotted line, and is independently attached to and detached from the casing 2 along the front-rear direction. Further, as indicated by the solid line, the lower cover 12 is covered by the closing operation of the lower cover 12.
In addition, each process unit 33 crosses the front surface 6 of the casing 2 that is opened and closed by the lower cover 12 as shown by a dotted line, and is attached / detached in a circular arc shape in the vertical direction along the front surface 6 outside the casing 2. Are attached to and detached from the casing 2.

As shown in FIG. 4, each process unit 33 includes a developing cartridge 38, a photosensitive drum 39 as a photosensitive member, a scorotron charger 40, and a drum cleaning roller 41.
The developing cartridge 38 includes a toner container 42, a supply roller 43, a developing roller 44, and a layer thickness regulating blade 45.

The toner accommodating portion 42 is formed as an internal space on the rear side of the developing cartridge 38, and a plurality (two) of agitators 46 are provided along the front-rear direction of the toner accommodating portion 42.
Further, in the toner container 42, for each process unit 33, yellow for the yellow process unit 33Y, magenta for the magenta process unit 33M, cyan for the cyan process unit 33C, and black for the black process unit 33K. Each toner is filled with a positively charged non-magnetic one-component developer having color.

  This toner includes a polymerizable monomer, for example, a styrene monomer such as styrene, and an acrylic monomer such as acrylic acid, alkyl (C1 to C4) acrylate, and alkyl (C1 to C4) methacrylate. A substantially spherical polymerized toner obtained by copolymerization by a known polymerization method such as suspension polymerization is used. Such toners are blended with colorants and waxes corresponding to the respective colors, and the flowability is improved by adding external additives such as silica. It is about 10 μm.

Then, the toner in the toner container 42 is discharged toward the supply roller 43 from the toner supply port opened on the front side of the toner container 42 by the rotation and agitation of the agitator 46 provided in the toner container 42.
The supply roller 43 is rotatably provided in front of the toner supply port. The supply roller 43 includes a metal roller shaft and a conductive sponge roller that covers the roller shaft.

The developing roller 44 is rotatably provided in front of the supply roller 43 so as to face the supply roller 43. The developing roller 44 is in contact with the supply roller 43 in a state where the supply roller 43 is compressed to some extent.
The developing roller 44 includes a metal roller shaft and a conductive rubber roller that covers the roller shaft. More specifically, the rubber roller of the developing roller 44 includes an elastic roller made of conductive urethane rubber, silicone rubber, EPDM rubber or the like containing carbon fine particles, and urethane rubber or urethane coated on the surface of the elastic roller. It is formed from a two-layer structure with a coating layer, the main component of which is resin, polyimide resin or the like. The developing roller 44 is disposed such that its front side portion is exposed from an opening formed in the front side portion of the developing cartridge 38, and a developing bias is applied from a power source (not shown) during development.

The layer thickness regulating blade 45 is provided with a pressing portion having a semicircular cross section made of insulating silicone rubber at the tip of a blade body made of a metal leaf spring material, and one end portion of the blade body is a developing roller 44. Is provided so that the pressing portion is pressed against the surface of the developing roller 44 by the elastic force of the blade body.
The toner discharged from the toner supply port is supplied to the developing roller 44 by the rotation of the supplying roller 43. At this time, the toner is positively frictionally charged between the supplying roller 43 and the developing roller 44, and further developed. The toner supplied onto the roller 44 enters between the pressing portion of the layer thickness regulating blade 45 and the developing roller 44 as the developing roller 44 rotates, and forms the developing roller 44 as a thin layer having a constant thickness. Is carried on.

  The photosensitive drum 39 is rotatably provided in the process unit 33 in front of the developing roller 44 so as to be in contact with the developing roller 44. The surface of the photosensitive drum 39 is grounded, and the surface thereof is formed by a photosensitive layer of an organic photosensitive member mainly composed of polycarbonate. Further, the photosensitive drum 39 is disposed such that the front side portion is exposed from an opening formed in the front side portion of the process unit 33.

  The scorotron charger 40 is provided above the photosensitive drum 39 at an interval so as not to contact the photosensitive drum 39. The scorotron charger 40 is a positively charged scorotron charger that generates corona discharge from a tungsten charging wire. The process unit 33 is configured to uniformly charge the surface of the photosensitive drum 39 to a positive polarity. It is fixed to.

  The drum cleaning roller 41 is rotatably provided in the process unit 33 so as to come into contact with the photosensitive drum 39 on the upstream side of the scorotron charger 40 in the rotation direction of the photosensitive drum 39. The drum cleaning roller 41 includes a metal roller shaft and a conductive rubber roller that covers the roller shaft. During cleaning, a cleaning bias is applied from a power source (not shown).

In the process unit 33, each color toner is exposed and developed as follows. That is, first, the surface of the photosensitive drum 39 is uniformly positively charged by the scorotron charger 40 by the rotation of the photosensitive drum 39, and then exposed by scanning the laser beam from the scanner unit 34 described in detail below. Then, an electrostatic latent image based on the image data is formed. Next, the electrostatic charge formed on the surface of the photosensitive drum 39 when the positively charged toner carried on the developing roller 44 comes into contact with the photosensitive drum 39 by the rotation of the developing roller 44. A latent image, that is, a toner image is formed by being selectively carried on a portion of the surface of the photosensitive drum 39 that is uniformly positively charged, which is exposed by scanning with a laser beam and whose potential is lowered. Thereby, reversal development is achieved.
b. As shown in FIG. 3, the scanner unit 34 is disposed below the paper feed unit 3 and the paper discharge unit 5 in the casing 2 so as to correspond to the process units 33 provided for different colors. A plurality (four) are provided and fixed to the casing 2. The scanner units 34 are arranged above the process units 33 and are arranged in parallel at intervals in the casing 2 so as to overlap in the vertical direction. Accordingly, the process units 33 and the scanner units 34 are alternately arranged in the casing 2 along the vertical direction.

As shown in FIG. 4, each scanner unit 34 includes a laser light emitting unit (not shown), a polygon mirror 47 that is rotationally driven, two lenses 48, and a reflecting mirror 49.
Then, the scanner unit 34 sequentially passes or reflects the laser beam based on the image data emitted from the laser emitting unit through the polygon mirror 47, the two lenses 48, and the reflecting mirror 49, as indicated by the arrows. As described above, the surface of the photosensitive drum 39 is irradiated by high-speed scanning.
c. As shown in FIG. 3, the transfer unit 35 is disposed between each process unit 33 and the lower cover 12 so as to face each process unit 33 arranged in parallel in the vertical direction in the casing 2. Is provided. The transfer unit 35 includes a transfer belt unit 50 and a belt cleaner unit 51 as a transport unit.

The transfer belt unit 50 is provided along the vertical direction so as to face the photosensitive drums 39 arranged in parallel along the vertical direction. The transfer belt unit 50 includes a transfer drive roller 53, a transfer driven roller 52, a transport belt 54, and a transfer roller 55.
The transfer driven roller 52 is disposed below the photosensitive drum 39 of the lowest yellow process unit 33Y. The transfer driving roller 53 is disposed above the photosensitive drum 39 of the uppermost black process unit 33K and below the fixing unit 37.

The conveyor belt 54 is made of conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed, and is wound between the transfer driving roller 53 and the transfer driven roller 52. The conveyor belt 54 is disposed such that the outer surface on the rear side in the wound state is in contact with all of the photosensitive drums 39 of the process units 33.
Then, the transfer driven roller 52 is driven by the drive of the transfer drive roller 53, and the conveying belt 54 is in contact with the photosensitive drum 39 of each process unit 33 between the transfer drive roller 53 and the transfer driven roller 52. The outer surface is rotated so as to rotate in the same direction as the photosensitive drum 39.

  The transfer roller 55 is provided in the wound conveyance belt 54 so as to face the photosensitive drum 39 of each process unit 33 with the conveyance belt 54 interposed therebetween. The transfer roller 55 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The transfer roller 55 is disposed so as to be in contact with the rear inner surface of the conveyor belt 54 and is provided so as to rotate in the same direction as the circumferential movement direction of the conveyor belt 54. A bias is applied.

The belt cleaner unit 51 is disposed on the opposite side (front side) of each photosensitive drum 39 in the transport belt 54 and is disposed between the transfer driving roller 53 and the transfer driven roller 52. The belt cleaner unit 51 includes a cleaning roller 56, a collection roller 57, a scraper 58, and a collection box 59.
The cleaning roller 56 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The cleaning roller 56 is disposed so as to come into contact with the front outer surface of the conveyor belt 54, and is provided rotatably on the belt cleaner unit 51 so as to rotate in the same direction as the circumferential movement direction of the conveyor belt 54. Sometimes, a primary cleaning bias is applied from a power source (not shown).

  The collection roller 57 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The collection roller 57 is disposed below the cleaning roller 56 so as to come into contact with the cleaning roller 56, and is rotatably provided to the belt cleaner unit 51. During cleaning, a secondary cleaning bias is applied from a power source (not shown). Is done.

The collection box 59 is disposed below the collection roller 57, a portion facing the collection roller 57 is opened, and a scraper 58 that is pressed against the surface of the collection roller 57 is provided in the vicinity of the opening portion. Yes.
The transfer portion 35 is integrally supported by the lower cover 12 of the casing 2. Therefore, when the lower cover 12 is opened, the transfer unit 35 moves integrally with the opened lower cover 12 and is separated from each process unit 33 as indicated by a dotted line. When the lower cover 12 is closed, the transfer unit 35 moves integrally with the closed lower cover 12 and is brought into pressure contact with the photosensitive drum 39 of each process unit 33 as indicated by a solid line.
d. Conveyance path The conveyance path 36 traverses the rear of each process unit 33 downward from the lower end of the paper feed unit 3 on the rear side, and after making a U-turn around the lowermost yellow process unit 33Y on the lower side On the front side, the sheet 31 is formed as a conveyance path for the paper 31 that crosses upward between the photosensitive drum 39 and the conveyance belt 54 of each process unit 33.

In the transport path 36, a plurality of transport rollers 60 are provided in the rear transport path, and the paper 31 is transported by the transport rollers 60 in the rear transport path. Further, the paper 31 is transported by the transport belt 54 in the transport path on the front side.
e. Fixing Unit The fixing unit 37 is disposed above the uppermost black process unit 33 </ b> K and the transfer unit 35 in the casing 2 and below the paper discharge unit 5. The fixing unit 37 includes a heating roller 61 and a pressing roller 62.

The heating roller 61 is rotatably supported in the casing 2 and includes a metal element tube such as aluminum and a halogen lamp disposed in the metal element tube. The outer peripheral surface of the metal base tube is subjected to a surface treatment for preventing toner adhesion.
The pressing roller 62 is disposed in front of the heating roller 61 so as to sandwich the sheet 31 passing through the fixing unit 37 in the front-rear direction. The pressing roller 62 includes a metal roller shaft and a rubber roller covered with the metal roller shaft, and is rotatably supported in the casing 2 so as to press the heating roller 61.
f. Image formation in the engine unit Then, the sheet 31 fed from the sheet feeding unit 3 is conveyed from the upper side to the lower side by the conveyance roller 60 in the conveyance path 36 along the rear conveyance path. After making a U-turn around the lower yellow process unit 33Y, the front conveyance path is conveyed from below to above by the conveyance belt 54.

  In the transport path on the front side, the paper 31 is transported by a transport belt 54 that is circulated by driving of the transfer drive roller 53 and driven of the transfer driven roller 52, and the transport belt 54 and the photosensitive drum 39 of each process unit 33. The toner images of the respective colors formed on the respective photosensitive drums 39 are sequentially transferred while passing therethrough (transfer position), whereby a color image is formed on the paper 3.

  That is, for example, when the yellow toner image formed on the photosensitive drum 39 of the yellow process unit 33Y is transferred to the paper 31, the magenta toner image formed on the photosensitive drum 39 of the magenta process unit 33M is then transferred. The toner image is transferred onto the paper 31 on which the yellow toner image has already been transferred, and then formed by the cyan process image 33C and the black process unit 33K by the same transfer operation. The black toner image is transferred in a superimposed manner, whereby a color image is formed on the paper 31.

  In forming such a color image, the color laser printer 1 is provided with the photosensitive drum 39 for each color, and the paper 31 is brought into contact with the photosensitive drums 39 in order, whereby the image of each color is directly applied to the paper 31. Since the transfer is a direct tandem type apparatus configuration, it is possible to form a toner image for each color at almost the same speed as that for forming a monochrome image, thereby achieving rapid color image formation.

The toner remaining on the surface of the photosensitive drum 39 after each color toner image is transferred to the paper 31 is temporarily captured by the drum cleaning roller 41 and returned to the photosensitive drum 39 during non-image formation. By being collected by the developing roller 44, it is used again for development.
Further, the toner adhering to the surface of the conveyance belt 54 after the color image is transferred to the paper 31 is applied to the cleaning roller 56 by the primary cleaning bias applied to the cleaning roller 56 when facing the cleaning roller 56. To be attached. Thereafter, the toner attached to the cleaning roller 56 was attached to the recovery roller 52 by the secondary cleaning bias applied to the recovery roller 57 when facing the recovery roller 57, and then scraped off by the scraper 58. Then, it is collected in a collection box 59.

Thereafter, the paper 31 on which the color image is formed is conveyed to the fixing unit 37, and the color image transferred onto the paper 31 by the heating roller 61 and the pressing roller 62 is transferred to the paper 3 by the heating roller 61 and the pressing roller 62. Thermal fixing is performed while passing between the rollers 62. The heat-fixed paper 31 is then conveyed to the paper discharge unit 5.
E. Paper Discharging Unit The paper discharging unit 5 is disposed on the upper front side of the casing 2 with respect to each process unit 33 of the engine unit 4. The paper discharge unit 5 is disposed to face the paper feed unit 3 with a space in the front-rear direction in the horizontal direction, and is opposed to the transfer unit 35 of the engine unit 4 in the vertical direction. The paper discharge unit 5 includes a paper discharge roller 63 and a paper discharge holder unit 64.

The paper discharge roller 63 is disposed above the fixing unit 37 and below the paper discharge holder unit 64. The paper discharge roller 63 includes a pair of rollers, and discharges the paper 31 on which the color image has been thermally fixed in the fixing unit 37 toward the paper discharge holder unit 64.
The paper discharge holder portion 64 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape when viewed from the front and capable of accommodating the paper 31 whose front side is covered or opened by the upper cover 11.

The paper 31 discharged by the paper discharge roller 63 is held in the vertical direction in the paper discharge holder portion 64. Further, the discharged paper 31 is stacked along the front-rear direction in the paper discharge holder portion 64.
The upper side of the paper discharge holder 64 is opened, and the discharged paper 31 can be taken out from the upper opening. Further, when the upper cover 11 is opened, the paper discharge holder portion 64 is released from the upper cover 11, so that the stacked sheets 31 can be taken out forward.
F. In the color laser printer 1, the paper 31 before color image formation is above the process units 33 of the engine unit 4, more specifically, the uppermost black process unit 33K. On the rear side, the sheet is held in the sheet feeding holder section 28 of the sheet feeding section 3 along the vertical direction. Further, the paper 31 after color image formation is stored in the paper discharge holder 64 of the paper discharge unit 5 on the front side above each process unit 33 of the engine unit 4, more specifically, the uppermost black process unit 33K. , Held along the vertical direction. Therefore, the installation area can be reduced regardless of the area of the paper 31 while having a plurality of process units 33.

  In the color laser printer 1, each process unit 33 can be attached to and detached from the casing 2 along the front-rear direction by opening the lower cover 12 to open each process unit 33. Therefore, when each process unit 33 is attached or detached, each process unit 33 does not interfere with the paper feed unit 3 and the paper discharge unit 5 disposed above the process unit 33, and each process unit 33 is attached to the casing 2. Can be easily attached and detached.

  Further, in this color laser printer 1, in the casing 2, the width of the paper 31 is the minimum required in the width direction, while the stacking direction can be formed significantly smaller than the width direction. It is formed in a slim vertically long shape. And if the casing 2 is formed in that way, the casing 2 may fall if it is moved in the front-rear direction. Therefore, in the color laser printer 1, the casing 2 is supported by the gantry 16 and can be moved only in the width direction by the casters 18. Thereby, while ensuring the movability of the casing 2, the movement of the casing 2 in the front-rear direction can be regulated to prevent the casing 2 from falling. In addition, when the color laser printer 1 is installed in a narrow space, the color laser printer 1 can be moved smoothly. Furthermore, it is possible to satisfactorily prevent the color laser printer 1 from moving when the process unit 33 is attached or detached.

  In the color laser printer 1, the height of the casing 2 can be changed by the height adjusting mechanism 20. Therefore, the optimum installation can be ensured by adjusting the height of the casing 2 in the vertical direction according to the installation environment. For example, when this color laser printer 1 is installed on the side of a desk, the height adjustment mechanism unit 20 matches the height of the upper surface 8 of the color laser printer 1 with the height of the desk, so The operability can be improved.

  Further, in this color laser printer 1, when the upper cover 11 is opened, the paper discharge holder 64 of the paper discharge unit 5 is opened, so that the stacked paper 31 can be taken out forward. Further, since the upper cover 11 swings with the upper opening / closing shaft 13 provided along the width direction as a fulcrum, it is compared with the case where the upper cover 11 swings with the upper opening / closing shaft 13 provided along the front-rear direction as a fulcrum. Thus, by the opening operation of the upper cover 11, the paper discharge holder portion 64 of the paper discharge portion 5 can be opened more widely.

  Further, in this color laser printer 1, since each process unit 33 is opened by opening the lower cover 12, each process unit 33 can be attached and detached independently. Further, since the lower cover 12 swings around the lower opening / closing shaft 14 provided along the width direction as a fulcrum, the lower cover 12 swings around the lower opening / closing shaft 14 provided along the front-rear direction. In contrast, each process unit 33 can be opened more widely by opening the lower cover 12.

  Further, in this color laser printer 1, since the upper cover 11 is disposed above the lower cover 12, the upper cover 11 and the lower cover 12 can be opened and closed independently without interfering with each other. Therefore, the paper discharge holder 64 of the paper discharge unit 5 can be opened and covered by the opening / closing operation of the upper cover 11, and each process unit 33 is opened independently by the opening / closing operation of the lower cover 12. And can be coated.

In the color laser printer 1, the upper cover 11 and the lower cover 12 are both disposed on the front surface of the casing 2. Therefore, the opening / closing operation of the upper cover 11 and the opening / closing operation of the lower cover 12 can be operated from the same side. As a result, operability can be improved.
Moreover, in this color laser printer 1, since the back surface 7 opposite to the front surface 6 of the casing 2 is formed in a flat shape, the back surface 7 is disposed near the wall so that it can be installed on the wall without any gap. Therefore, further space saving can be achieved.

In the color laser printer 1, an operation panel 15 is provided on the upper surface 8 of the casing 2. Therefore, even if it is installed in a narrow space (for example, between a desk and the like), the operation panel 15 can be easily operated from above.
In the color laser printer 1, the fixing unit 37 is disposed in the casing 2 above the uppermost black process unit 33 </ b> K and below the paper discharge unit 5. Therefore, it is possible to reduce the influence of heat generated from the fixing unit 37 on each process unit 33 while reducing the size of the apparatus.

In the color laser printer 1, the process units 33 and the scanner units 34 are alternately arranged along the vertical direction. Therefore, compared with the case where the process unit 33 and the scanner unit 34 are arranged in the front-rear direction, the apparatus can be further slimmed.
In the color laser printer 1, the paper feed unit 3 and the paper discharge unit 5 are disposed above the engine unit 4 so as to face each other with a gap in the horizontal direction. Therefore, the size in the vertical direction can be made compact, and the upper surface 8 of the casing 2 can be made flat.

Further, in this color laser printer 1, the paper 31 is fed from the paper feed unit 3 along the transport path 36, passed through the photosensitive drums 39 of all the process units 33, and then discharged. Paper can be discharged to the paper section 5. Therefore, it is possible to efficiently convey the paper 31 and form a color image while reducing the size of the apparatus.
More specifically, in the transfer belt unit 50 of the transfer unit 35, the paper 31 can be transported by the transport belt 54 so as to sequentially face the photosensitive drum 39 of each process unit 33. Therefore, a direct tandem type device configuration can be obtained.

The transfer belt unit 50 is disposed so as to face the paper discharge unit 5 in the vertical direction. Therefore, in each process unit 33, after a color image is formed on the paper 31, the paper 31 on which the color image is formed can be discharged directly upward. As a result, the paper 31 can be discharged to the paper discharge unit 5 without deteriorating the image quality.
Each process unit 33 crosses the front surface 6 of the casing 2 that is opened and closed by the lower cover 12 as shown by a dotted line in FIG. It is attached to and detached from the casing 2 along the attached and detached route. Therefore, the width around the casing 2 is slightly wider than the thickness of each process unit 33 that is attached / detached along the attachment / detachment path outside the casing 2 (the vertical width of the process unit 33). As long as a space having a width of 2 is secured, the space occupied by the color laser printer 1 can be reduced. As a result, the degree of freedom of the installation place of the color laser printer 1 can be increased.
(Second Embodiment)
FIG. 5 is a side sectional view showing a second embodiment of the color laser printer as the image forming apparatus of the present invention, and FIG. 6 is an enlarged side sectional view of the main part of the process unit and the scanner section shown in FIG. Hereinafter, in the second embodiment, only the parts different from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted. Moreover, the same reference numerals are given to the same members as those in the first embodiment.
A. Overall Configuration of Device In FIG. 5, the color laser printer 1 has a configuration of a vertical-type direct tandem type color laser printer as in the first embodiment, and includes a paper feed unit 3 and a paper discharge unit 5. Is arranged on the opposite side to the first embodiment in the front-rear direction.
B. Casing The casing 2 includes an upper cover 11 and a lower cover 12 as in the first embodiment. The upper cover 11 opens and covers the paper feeding unit 5, and the lower cover 12 opens the engine unit 4. And coat. A transport path on the front side of a later-described transport path 36 is fixed to the lower cover 12, and the transport path on the front side of the transport path 36 moves together with the lower cover 12 by opening and closing operations of the lower cover 12.
C. Paper Feed Unit The paper feed unit 3 is disposed in the casing 2 on the upper front side with respect to each process unit 33 of the engine unit 4. The paper feed unit 3 includes a paper feed holder unit 28 that holds the paper 31, a paper pressing plate 29 that is disposed in the paper feed holder unit 28, and a paper feeder that is disposed in front of the lower end of the paper feed holder unit 28. And a paper roller 30.

  The paper feed holder portion 28 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape in front view that can accommodate the paper 31 and whose front side is covered or opened by the upper cover 11. The upper side of the paper feed holder portion 28 is open, and the paper 31 can be inserted into the upper opening and set on the paper pressing plate 29. Further, when the upper cover 11 is opened, the paper feed holder portion 28 is released from the upper cover 11, so that the paper 31 can be set from the front.

In the sheet feeding unit 3, the sheet 31 is held on the sheet pressing plate 29 in the sheet feeding holder unit 28 along the vertical direction, and runs in the front-rear direction against the urging force of the pressing spring 32. Are stacked. The uppermost (first) paper 31 stacked on the paper pressing plate 29 is pressed so as to come into contact with the paper feed roller 30 by the urging force of the spring 25, and by rotation of the paper feed roller 30, for each sheet, Paper is fed toward the engine unit 4.
D. Engine Unit The engine unit 4 includes a process unit 33, a scanner unit 34, a transfer unit 35, a transport path 36, and a fixing unit 37, as in the first embodiment.
a. Process Unit The process unit 33 is disposed below the paper feed unit 3 and the paper discharge unit 5 in the casing 2, and a plurality (four) of different colors are provided, and is detachably attached to the casing 2. ing.

Each process unit 33 is opened from the lower cover 12 by the opening operation of the lower cover 12 as indicated by a dotted line, and is independently attached to and detached from the casing 2 along the front-rear direction. Further, as indicated by the solid line, the lower cover 12 is covered by the closing operation of the lower cover 12.
In each process unit 33, as shown in FIG. 6, the developing cartridge 38, the photosensitive drum 39, the scorotron charger 40, and the drum cleaning roller 41 are arranged on the opposite side to the first embodiment in the front-rear direction. .

That is, in the developing cartridge 38, the toner accommodating portion 42 is formed as an internal space on the front side of the developing cartridge 38, and the toner in the toner accommodating portion 42 is rotated and agitated by the agitator 46 provided in the toner accommodating portion 42. Then, the toner is discharged toward the supply roller 43 from the toner supply port opened on the rear side of the toner accommodating portion 42.
The supply roller 43 is rotatably provided behind the toner supply port, and the developing roller 44 is rotatably provided so as to face the supply roller 43 behind the supply roller 43. Further, the developing roller 44 is disposed so that the rear side portion is exposed from an opening formed in the rear side portion of the developing cartridge 38.

The layer thickness regulating blade 45 is provided in the vicinity of the upper portion of the developing roller 44 so that the pressing portion is pressed against the surface of the developing roller 44.
The toner discharged from the toner supply port is supplied to the developing roller 44 by the rotation of the supplying roller 43. At this time, the toner is positively frictionally charged between the supplying roller 43 and the developing roller 44, and further developed. The toner supplied onto the roller 44 enters between the pressing portion of the layer thickness regulating blade 45 and the developing roller 44 as the developing roller 44 rotates, and forms the developing roller 44 as a thin layer having a constant thickness. Is carried on.

The photosensitive drum 39 is provided in the process unit 33 so as to be rotatable behind the developing roller 44 so as to be in contact with the developing roller 44. Further, the photosensitive drum 39 is disposed so that the rear side portion is exposed from an opening formed in the rear side portion of the process unit 33.
The scorotron charger 40 is provided above the photosensitive drum 39 at an interval so as not to contact the photosensitive drum 39.

The drum cleaning roller 41 is rotatably provided in the process unit 33 so as to come into contact with the photosensitive drum 39 on the upstream side of the scorotron charger 40 in the rotation direction of the photosensitive drum 39.
In the process unit 33, a toner image for each color is formed on each photosensitive drum 39 by the same operation as in the first embodiment.
b. As shown in FIG. 5, the scanner unit 34 is disposed below the paper feed unit 3 and the paper discharge unit 5 in the casing 2 so as to correspond to the process units 33 provided for different colors. A plurality (four) are provided and fixed to the casing 2. The scanner units 34 are arranged above the process units 33 and are arranged in parallel at intervals in the casing 2 so as to overlap in the vertical direction. Accordingly, the process units 33 and the scanner units 34 are alternately arranged in the casing 2 along the vertical direction.

In the scanner unit 34, as shown in FIG. 6, the laser beam based on the image data emitted from the laser emitting unit sequentially passes through the polygon mirror 47, the two lenses 48, and the reflecting mirror 49 as indicated by arrows. Alternatively, the light is reflected and irradiated onto the surface of the photosensitive drum 39 by high-speed scanning as described above.
c. As shown in FIG. 5, the transfer unit 35 is provided between each process unit 33 and the back surface 7 so as to face each process unit 33 arranged in parallel in the vertical direction in the casing 2. It has been. The transfer unit 35 includes a transfer belt unit 50 and a belt cleaner unit 51.

The transfer belt unit 50 is provided along the vertical direction so as to face the photosensitive drums 39 arranged in parallel along the vertical direction.
In the transfer belt unit 50, the transfer driven roller 52 is driven by the drive of the transfer drive roller 53, and the conveying belt 54 is connected between the transfer drive roller 53 and the transfer driven roller 52 with the photosensitive drum 39 of each process unit 33. The front outer surface in contact with the photosensitive drum 39 is rotated so as to rotate in the same direction.

The transfer roller 55 is provided in the wound conveyance belt 54 so as to face the photosensitive drum 39 of each process unit 33 with the conveyance belt 54 interposed therebetween.
The belt cleaner unit 51 has the same configuration as that of the first embodiment, and the cleaning roller 56 is in contact with the rear outer surface of the conveyor belt 54 on the opposite side (rear side) of each photosensitive drum 39 in the conveyor belt 54. As described above, the transfer driving roller 53 and the transfer driven roller 52 are disposed.
d. Conveyance path The conveyance path 36 traverses the front of each process unit 33 downward from the lower end of the paper feed unit 3 on the front side, and after making a U-turn around the lowermost yellow process unit 33Y on the lower side, On the rear side, it is formed as a conveyance path for the paper 31 that crosses upward between the photosensitive drum 39 and the conveyance belt 54 of each process unit 33.

In the transport path 36, a plurality of transport rollers 60 are provided in the front transport path, and the paper 31 is transported by the transport rollers 60 in the front transport path. Further, the paper 31 is transported by the transport belt 54 in the rear transport path.
The transport path on the front side of the transport path 36 is integrally supported by the lower cover 12 of the casing 2. Therefore, when the lower cover 12 is opened, the conveyance path on the front side of the conveyance path 36 moves integrally with the opened lower cover 12 and is separated from each process unit 33 as indicated by a dotted line. When the lower cover 12 is closed, the conveyance path on the front side of the conveyance path 36 moves integrally with the closed lower cover 12 and approaches each process unit 33 as indicated by a solid line.
e. Fixing Unit The fixing unit 37 is disposed above the uppermost black process unit 33 </ b> K and the transfer unit 35 in the casing 2 and below the paper discharge unit 5. The fixing unit 37 includes a heating roller 61 and a pressing roller 62 as in the first embodiment.
f. Image formation in the engine unit The sheet 31 fed from the sheet feeding unit 3 is conveyed from the upper side to the lower side by the conveyance roller 60 in the conveyance path 36 on the front side conveyance path. After the U-turn of the yellow process unit 33Y, the rear transport path is transported from below to above by the transport belt 54.

  In the rear conveyance path, the paper 31 is conveyed by a conveyance belt 54 that is circulated by the drive of the transfer drive roller 53 and the follower of the transfer driven roller 52, and the conveyance belt 54 and the photosensitive drum 39 of each process unit 33. The toner images of the respective colors formed on the respective photosensitive drums 39 are sequentially transferred in the same manner as in the first embodiment, so that the sheet of paper is transferred. A color image is formed on 3.

Thereafter, the paper 31 on which the color image is formed is thermally fixed in the fixing unit 37 and then conveyed to the paper discharge unit 5.
E. Paper Discharge Unit The paper discharge unit 5 is disposed in the casing 2 on the upper rear side with respect to each process unit 33 of the engine unit 4. The paper discharge unit 5 is disposed to face the paper feed unit 3 with a gap in the front-rear direction in the horizontal direction, and is opposed to the transfer unit 35 of the engine unit 4 in the vertical direction. The paper discharge unit 5 includes a paper discharge roller 63 and a paper discharge holder unit 64.

The paper discharge roller 63 is disposed above the fixing unit 37 and below the paper discharge holder unit 64, and the paper 31 on which the color image is thermally fixed in the fixing unit 37 is directed toward the paper discharge holder unit 64. Eject paper.
The paper discharge holder portion 64 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape in front view that can accommodate the paper 31. The discharge holder unit 64 is open on the upper side, and the depth in the vertical direction is set so that the discharged paper 31 is exposed from the upper opening. The paper 31 discharged by the paper discharge roller 63 is held in the vertical direction in the paper discharge holder 64 with the upper end protruding from the casing 2. Further, the discharged paper 31 is stacked along the front-rear direction in the paper discharge holder portion 64.
F. Effects of the Second Embodiment In the color laser printer 1 of the second embodiment, the paper 31 before color image formation is the process unit 33 of the engine unit 4, more specifically, the uppermost black process unit. It is held along the vertical direction in the paper feed holder 28 of the paper feed unit 3 on the front side above 33K. Further, the paper 31 after the color image is formed is disposed on each process unit 33 of the engine unit 4, more specifically on the upper rear side of the uppermost black process unit 33K, and on the paper discharge holder unit 64 of the paper discharge unit 5. In FIG. Therefore, similarly to the color laser printer 1 of the first embodiment, the installation area can be reduced regardless of the area of the paper 31 while having a plurality of process units 33.

  In the color laser printer 1, each process unit 33 can be attached to and detached from the casing 2 along the front-rear direction by opening the lower cover 12 to open each process unit 33. Therefore, when each process unit 33 is attached or detached, each process unit 33 does not interfere with the paper feed unit 3 and the paper discharge unit 5 disposed above the process unit 33, and each process unit 33 is attached to the casing 2. Can be easily attached and detached.

  Further, in this color laser printer 1, when the upper cover 11 is opened, the paper feed holder portion 28 of the paper feed portion 3 is opened, so that the paper 31 is placed on the paper pressing plate 29 in the paper feed holder portion 28. In addition, it can be set in a laminated form. Further, since the upper cover 11 swings with the upper opening / closing shaft 13 provided along the width direction as a fulcrum, it is compared with the case where the upper cover 11 swings with the upper opening / closing shaft 13 provided along the front-rear direction as a fulcrum. As a result of the opening operation of the upper cover 11, the paper feed holder section 28 of the paper feed section 3 can be opened more widely.

  Further, in this color laser printer 1, since each process unit 33 is opened by opening the lower cover 12, each process unit 33 can be attached and detached independently. Further, since the lower cover 12 swings around the lower opening / closing shaft 14 provided along the width direction as a fulcrum, the lower cover 12 swings around the lower opening / closing shaft 14 provided along the front-rear direction. In contrast, each process unit 33 can be opened more widely by opening the lower cover 12.

Further, in this color laser printer 1, since the upper cover 11 is disposed above the lower cover 12, the upper cover 11 and the lower cover 12 can be opened and closed independently without interfering with each other. Therefore, the paper supply holder 28 of the paper supply unit 3 can be opened and covered by the opening / closing operation of the upper cover 11, and each process unit 33 is opened independently by the opening / closing operation of the lower cover 12. And can be coated.
(Third embodiment)
FIG. 7 is a side sectional view showing a third embodiment of a color laser printer as an image forming apparatus of the present invention, and FIG. 8 is an enlarged side sectional view of main parts of the process unit and the scanner section shown in FIG. Hereinafter, in the third embodiment, only portions different from the first embodiment will be described, and the description of the same portions as the first embodiment will be omitted. Moreover, the same reference numerals are given to the same members as those in the first embodiment.
A. Overall Configuration of the Device In FIG. 7, the color laser printer 1 is different from the first embodiment in that it has the configuration of a vertical type intermediate transfer tandem type color laser printer. 5 is arrange | positioned in the front-back direction on the opposite side to 1st Embodiment.
B. Casing The casing 2 includes an upper cover 11 and a lower cover 12 as in the first embodiment. The upper cover 11 opens and covers the paper feeding unit 5, and the lower cover 12 opens the engine unit 4. And coat. A transport path on the front side of a later-described transport path 36 is fixed to the lower cover 12, and the transport path on the front side of the transport path 36 moves together with the lower cover 12 by opening and closing operations of the lower cover 12.
C. Paper Feed Unit The paper feed unit 3 is disposed in the casing 2 on the upper front side with respect to each process unit 33 of the engine unit 4. The paper feed unit 3 includes a paper feed holder unit 28 that holds the paper 31, a paper pressing plate 29 that is disposed in the paper feed holder unit 28, and a paper feeder that is disposed in front of the lower end of the paper feed holder unit 28. And a paper roller 30.

  The paper feed holder portion 28 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape in front view that can accommodate the paper 31 and whose front side is covered or opened by the upper cover 11. The upper side of the paper feed holder portion 28 is open, and the paper 31 can be inserted into the upper opening and set on the paper pressing plate 29. Further, when the upper cover 11 is opened, the paper feed holder portion 28 is released from the upper cover 11, so that the paper 31 can be set from the front.

In the sheet feeding unit 3, the sheet 31 is held on the sheet pressing plate 29 in the sheet feeding holder unit 28 along the vertical direction, and runs in the front-rear direction against the urging force of the pressing spring 32. Are stacked. The uppermost (first) paper 31 stacked on the paper pressing plate 29 is pressed so as to come into contact with the paper feed roller 30 by the urging force of the spring 25, and by rotation of the paper feed roller 30, for each sheet, Paper is fed toward the engine unit 4.
D. Engine Unit The engine unit 4 includes a process unit 33, a scanner unit 34, a transfer unit 35, a transport path 36, and a fixing unit 37, as in the first embodiment.
a. Process Unit The process unit 33 is disposed below the paper feed unit 3 and the paper discharge unit 5 in the casing 2, and a plurality (four) of different colors are provided, and is detachably attached to the casing 2. ing. More specifically, the process unit 33 includes four process units 33 of a yellow process unit 33Y, a magenta process unit 33M, a cyan process unit 33C, and a black process unit 33K in order from the top to the bottom in the casing 2. These are arranged in parallel so as to be spaced apart from each other so as to overlap in the vertical direction.

Each process unit 33 is opened from the lower cover 12 by the opening operation of the lower cover 12 as indicated by a dotted line, and is independently attached to and detached from the casing 2 along the front-rear direction. Further, as indicated by the solid line, the lower cover 12 is covered by the closing operation of the lower cover 12.
In each process unit 33, as shown in FIG. 8, the developing cartridge 38, the photosensitive drum 39, the scorotron charger 40, and the drum cleaning roller 41 are arranged on the opposite side of the first embodiment in the front-rear direction and the vertical direction. Has been.

That is, in the developing cartridge 38, the toner accommodating portion 42 is formed as an internal space on the front side of the developing cartridge 38, and the toner in the toner accommodating portion 42 is rotated and agitated by the agitator 46 provided in the toner accommodating portion 42. Then, the toner is discharged toward the supply roller 43 from the toner supply port opened on the rear side of the toner accommodating portion 42.
The supply roller 43 is rotatably provided behind the toner supply port, and the developing roller 44 is rotatably provided so as to face the supply roller 43 behind the supply roller 43. Further, the developing roller 44 is disposed so that the rear side portion is exposed from an opening formed in the rear side portion of the developing cartridge 38.

The layer thickness regulating blade 45 is provided in the vicinity of the lower portion of the developing roller 44 so that the pressing portion is pressed against the surface of the developing roller 44.
The toner discharged from the toner supply port is supplied to the developing roller 44 by the rotation of the supplying roller 43. At this time, the toner is positively frictionally charged between the supplying roller 43 and the developing roller 44, and further developed. The toner supplied onto the roller 44 enters between the pressing portion of the layer thickness regulating blade 45 and the developing roller 44 as the developing roller 44 rotates, and forms the developing roller 44 as a thin layer having a constant thickness. Is carried on.

The photosensitive drum 39 is provided in the process unit 33 so as to be rotatable behind the developing roller 44 so as to be in contact with the developing roller 44. Further, the photosensitive drum 39 is disposed so that the rear side portion is exposed from an opening formed in the rear side portion of the process unit 33.
The scorotron charger 40 is provided below the photosensitive drum 39 at an interval so as not to contact the photosensitive drum 39.

The drum cleaning roller 41 is rotatably provided in the process unit 33 so as to come into contact with the photosensitive drum 39 on the upstream side of the scorotron charger 40 in the rotation direction of the photosensitive drum 39.
In the process unit 33, a toner image for each color is formed on each photosensitive drum 39 by the same operation as in the first embodiment.
b. As shown in FIG. 7, the scanner unit 34 is disposed below the paper feed unit 3 and the paper discharge unit 5 in the casing 2, and corresponds to the process unit 33 provided for each different color. A plurality (four) are provided and fixed to the casing 2. The scanner units 34 are arranged below the process units 33, and are arranged in parallel at intervals in the casing 2 so as to overlap in the vertical direction. Accordingly, the process units 33 and the scanner units 34 are alternately arranged in the casing 2 along the vertical direction.

Then, as shown in FIG. 8, the scanner unit 34 sequentially passes the laser beam based on the image data emitted from the laser emitting unit through the polygon mirror 47, the two lenses 48, and the reflecting mirror 49 as indicated by arrows. Alternatively, the light is reflected and irradiated onto the surface of the photosensitive drum 39 by high-speed scanning as described above.
c. As shown in FIG. 7, the transfer unit 35 is provided between each process unit 33 and the back surface 7 so as to face each process unit 33 arranged in parallel in the vertical direction in the casing 2. It has been. The transfer unit 35 includes an intermediate transfer unit 65 as an intermediate transfer unit and a belt cleaner unit 51.

The intermediate transfer unit 65 is provided along the vertical direction so as to face the photosensitive drums 39 arranged in parallel along the vertical direction. The intermediate transfer unit 65 includes a driving roller 67, two driven rollers 66, a transfer belt 68, a primary transfer roller 69, and a secondary transfer roller 70.
The drive roller 67 is disposed below the photosensitive drum 39 of the lowest black process unit 33K. One driven roller 66 is disposed above the photosensitive drum 39 of the uppermost yellow process unit 33Y. The other driven roller 66 is disposed so as to face rearward with respect to the one driven roller 66. The driving roller 67 and the two driven rollers 66 are relatively arranged so as to have a triangular shape in a side view.

The transfer belt 68 is made of conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed, and is wound between a driving roller 67 and two driven rollers 66. The transfer belt 68 is arranged so that the front outer surface in a wound state is in contact with all of the photosensitive drums 39 of the process units 33.
The two driven rollers 66 are driven by the driving roller 67, and the transfer belt 68 is in contact with the photosensitive drum 39 of each process unit 33 between the driving roller 67 and the two driven rollers 66. The outer surface is rotated so as to rotate in the same direction as the photosensitive drum 39.

  The primary transfer roller 69 is provided in the wound transfer belt 68 so as to face the photosensitive drum 39 of each process unit 33 with the transfer belt 68 interposed therebetween. The primary transfer roller 69 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The primary transfer roller 69 is disposed so as to be in contact with the front inner surface of the transfer belt 68, and is provided to rotate in the same direction as the circumferential movement direction of the transfer belt 68. A primary transfer bias is applied.

  The secondary transfer roller 70 is provided outside the wound transfer belt 68 and is opposed to the other driven roller 66 with the transfer belt 68 interposed therebetween. The secondary transfer roller 70 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The secondary transfer roller 70 is disposed so as to be in contact with the rear outer surface of the transfer belt 68, and is provided so as to rotate in the same direction as the circumferential movement direction of the transfer belt 68. To the secondary transfer bias.

The belt cleaner unit 51 has the same configuration as that of the first embodiment, and is located outside the wound transfer belt 68 so that the cleaning roller 56 faces one driven roller 66 and the transfer belt 68 therebetween. Is arranged.
d. Conveyance path The conveyance path 36 traverses the front of each process unit 33 downward from the lower end of the paper feed unit 3 on the front side, and makes a U-turn around the lowermost black process unit 33K on the lower side. On the rear side, it is formed as a conveyance path for the paper 31 that crosses the back of the transfer belt 68.

In the transport path 36, a plurality of transport rollers 60 are provided in the front and rear transport paths, and the paper 31 is transported by these transport rollers 60.
The transport path on the front side of the transport path 36 is integrally supported by the lower cover 12 of the casing 2. Therefore, when the lower cover 12 is opened, the conveyance path on the front side of the conveyance path 36 moves integrally with the opened lower cover 12 and is separated from each process unit 33 as indicated by a dotted line. When the lower cover 12 is closed, the conveyance path on the front side of the conveyance path 36 moves integrally with the closed lower cover 12 and approaches each process unit 33 as indicated by a solid line.
e. Fixing Unit The fixing unit 37 is disposed above the uppermost yellow process unit 33 </ b> Y and the secondary transfer roller 70 in the casing 2 and below the paper discharge unit 5. The fixing unit 37 includes a heating roller 61 and a pressing roller 62 as in the first embodiment.
f. Image formation in the engine unit The sheet 31 fed from the sheet feeding unit 3 is conveyed from the upper side to the lower side by the conveyance roller 60 in the conveyance path 36 on the front side conveyance path. After making a U-turn around the black process unit 33K, the rear conveyance path is conveyed from below to above by the conveyance roller 60.

On the other hand, in the transfer section 35, the transfer belt 68 is rotated around by the drive of the driving roller 67 and the driven of the two driven rollers 66, and is formed on each photosensitive drum 39 on the transferred transfer belt 68. The toner images of the respective colors are sequentially transferred, whereby a color image is formed on the transfer belt 68.
When the paper 31 passes between the other driven roller 66 and the secondary transfer roller 70, the color image formed on the transfer belt 68 is collectively transferred to the paper 3.

Thereafter, the paper 31 on which the color image is formed is thermally fixed in the fixing unit 37 and then conveyed to the paper discharge unit 5.
E. Paper Discharge Unit The paper discharge unit 5 is disposed in the casing 2 on the upper rear side with respect to each process unit 33 of the engine unit 4. The paper discharge unit 5 is disposed to face the paper feed unit 3 with a gap in the front-rear direction in the horizontal direction, and is opposed to the transfer unit 35 of the engine unit 4 in the vertical direction. The paper discharge unit 5 includes a paper discharge roller 63 and a paper discharge holder unit 64.

The paper discharge roller 63 is disposed above the fixing unit 37 and below the paper discharge holder unit 64, and the paper 31 on which the color image is thermally fixed in the fixing unit 37 is directed toward the paper discharge holder unit 64. Eject paper.
The paper discharge holder portion 64 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape in front view that can accommodate the paper 31. The discharge holder unit 64 is open on the upper side, and the depth in the vertical direction is set so that the discharged paper 31 is exposed from the upper opening. The paper 31 discharged by the paper discharge roller 63 is held in the vertical direction in the paper discharge holder portion 64 in a normal state where the upper end portion protrudes from the casing 2. Further, the discharged paper 31 is stacked along the front-rear direction in the paper discharge holder portion 64.
F. Effects of the Third Embodiment In the color laser printer 1 of the third embodiment, the paper 31 before color image formation is the process unit 33 of the engine unit 4, more specifically, the uppermost yellow process unit. It is held along the vertical direction in the paper feed holder section 28 of the paper feed section 3 on the front side above 33Y. Further, the paper 31 after color image formation is the discharge unit 5 of the discharge unit 5 on the rear side above each process unit 33 of the engine unit 4, more specifically, the uppermost yellow process unit 33Y. In FIG. Therefore, similarly to the color laser printer 1 of the first embodiment, the installation area can be reduced regardless of the area of the paper 31 while having a plurality of process units 33.

  In the color laser printer 1, each process unit 33 can be attached to and detached from the casing 2 along the front-rear direction by opening the lower cover 12 to open each process unit 33. Therefore, when each process unit 33 is attached or detached, each process unit 33 does not interfere with the paper feed unit 3 and the paper discharge unit 5 disposed above the process unit 33, and each process unit 33 is attached to the casing 2. Can be easily attached and detached.

  Further, in this color laser printer 1, when the upper cover 11 is opened, the paper feed holder portion 28 of the paper feed portion 3 is opened, so that the paper 31 is placed on the paper pressing plate 29 in the paper feed holder portion 28. In addition, it can be set in a laminated form. Further, since the upper cover 11 swings with the upper opening / closing shaft 13 provided along the width direction as a fulcrum, the upper cover 11 is compared with the case where the upper cover 11 swings with the upper opening / closing shaft 13 provided along the front-rear direction as a fulcrum. As a result of the opening operation of the upper cover 11, the paper feed holder section 28 of the paper feed section 3 can be opened more widely.

  Further, in this color laser printer 1, since each process unit 33 is opened by opening the lower cover 12, each process unit 33 can be attached and detached independently. Further, since the lower cover 12 swings around the lower opening / closing shaft 14 provided along the width direction as a fulcrum, the lower cover 12 swings around the lower opening / closing shaft 14 provided along the front-rear direction. In contrast, each process unit 33 can be opened more widely by opening the lower cover 12.

  Further, in this color laser printer 1, since the upper cover 11 is disposed above the lower cover 12, the upper cover 11 and the lower cover 12 can be opened and closed independently without interfering with each other. Therefore, the paper supply holder 28 of the paper supply unit 3 can be opened and covered by the opening / closing operation of the upper cover 11, and each process unit 33 is opened independently by the opening / closing operation of the lower cover 12. And can be coated.

In the color laser printer 1, the toner image for each color from the photosensitive drum 39 of each process unit is primarily transferred and superimposed on the transfer belt 68 in the intermediate transfer unit 65, and the superimposed color image is Secondary transfer is performed collectively on the paper 31. Therefore, an intermediate transfer tandem type apparatus configuration can be obtained.
The intermediate transfer unit 65 is disposed so as to face the paper discharge unit 5 in the vertical direction. Therefore, in each process unit 33, after a color image is formed on the paper 31, the paper 31 on which the color image is formed can be discharged directly upward. As a result, the paper 31 can be discharged to the paper discharge unit 5 without deteriorating the image quality.
(Fourth embodiment)
FIG. 9 is a side sectional view showing a fourth embodiment of the color laser printer as the image forming apparatus of the present invention, and FIG. 9 is an enlarged side sectional view of the main part of the process unit and the scanner unit shown in FIG. Hereinafter, only the parts different from the first embodiment will be described in the fourth embodiment, and the description of the same parts as in the first embodiment will be omitted. Moreover, the same reference numerals are given to the same members as those in the first embodiment.
A. Overall Configuration of the Device In FIG. 9, the color laser printer 1 is different from the first embodiment in that it has a configuration of a vertical type intermediate transfer tandem type color laser printer. 5 is arrange | positioned in the front-back direction on the opposite side to 1st Embodiment. Further, unlike the third embodiment, the transport path 36 is arranged above the process units 33 and the transfer unit 35.
B. Casing The casing 2 includes an upper cover 11 and a lower cover 12 as in the first embodiment. The upper cover 11 opens and covers the paper feeding unit 5, and the lower cover 12 opens the engine unit 4. And coat. Note that the lower cover 12 does not support the transfer unit 35.
C. Paper Feed Unit The paper feed unit 3 is disposed in the casing 2 on the upper front side with respect to each process unit 33 of the engine unit 4. The paper feed unit 3 includes a paper feed holder unit 28 that holds the paper 31, a paper pressing plate 29 that is disposed in the paper feed holder unit 28, and a paper feeder that is disposed in front of the lower end of the paper feed holder unit 28. And a paper roller 30.

  The paper feed holder portion 28 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape in front view that can accommodate the paper 31 and whose front side is covered or opened by the upper cover 11. The upper side of the paper feed holder portion 28 is open, and the paper 31 can be inserted into the upper opening and set on the paper pressing plate 29. Further, when the upper cover 11 is opened, the paper feed holder portion 28 is released from the upper cover 11, so that the paper 31 can be set from the front.

In the sheet feeding unit 3, the sheet 31 is held on the sheet pressing plate 29 in the sheet feeding holder unit 28 along the vertical direction, and runs in the front-rear direction against the urging force of the pressing spring 32. Are stacked. The uppermost (first) paper 31 stacked on the paper pressing plate 29 is pressed so as to come into contact with the paper feed roller 30 by the urging force of the spring 25, and by rotation of the paper feed roller 30, for each sheet, Paper is fed toward the engine unit 4.
D. Engine Unit The engine unit 4 includes a process unit 33, a scanner unit 34, a transfer unit 35, a transport path 36, and a fixing unit 37, as in the first embodiment.
a. Process unit The process unit 33 is disposed in the casing 2 on the lower front side of the paper feed unit 3 and the paper discharge unit 5 and is provided in a plurality (four) for each different color. Has been.

Each process unit 33 is opened from the lower cover 12 by the opening operation of the lower cover 12 as indicated by a dotted line, and is independently attached to and detached from the casing 2 along the front-rear direction. Further, as indicated by the solid line, the lower cover 12 is covered by the closing operation of the lower cover 12.
In each process unit 33, as shown in FIG. 10, the developing cartridge 38, the photosensitive drum 39, the scorotron charger 40, and the drum cleaning roller 41 are arranged on the opposite side to the first embodiment in the front-rear direction. .

That is, in the developing cartridge 38, the toner accommodating portion 42 is formed as an internal space on the front side of the developing cartridge 38, and the toner in the toner accommodating portion 42 is rotated and agitated by the agitator 46 provided in the toner accommodating portion 42. Then, the toner is discharged toward the supply roller 43 from a toner supply port opened on the rear side of the toner accommodating portion 42.
The supply roller 43 is rotatably provided behind the toner supply port, and the developing roller 44 is rotatably provided so as to face the supply roller 43 behind the supply roller 43. Further, the developing roller 44 is disposed so that the rear side portion is exposed from an opening formed in the rear side portion of the developing cartridge 38.

The layer thickness regulating blade 45 is provided in the vicinity of the upper portion of the developing roller 44 so that the pressing portion is pressed against the surface of the developing roller 44.
The toner discharged from the toner supply port is supplied to the developing roller 44 by the rotation of the supplying roller 43. At this time, the toner is positively frictionally charged between the supplying roller 43 and the developing roller 44, and further developed. The toner supplied onto the roller 44 enters between the pressing portion of the layer thickness regulating blade 45 and the developing roller 44 as the developing roller 44 rotates, and forms the developing roller 44 as a thin layer having a constant thickness. Is carried on.

The photosensitive drum 39 is provided in the process unit 33 so as to be rotatable behind the developing roller 44 so as to be in contact with the developing roller 44. Further, the photosensitive drum 39 is disposed so that the rear side portion is exposed from an opening formed in the rear side portion of the process unit 33.
The scorotron charger 40 is provided above the photosensitive drum 39 at an interval so as not to contact the photosensitive drum 39.

The drum cleaning roller 41 is rotatably provided in the process unit 33 so as to come into contact with the photosensitive drum 39 on the upstream side of the scorotron charger 40 in the rotation direction of the photosensitive drum 39.
In the process unit 33, a toner image for each color is formed on each photosensitive drum 39 by the same operation as in the first embodiment.
b. As shown in FIG. 9, the scanner unit 34 is arranged below the paper feed unit 3 and the paper discharge unit 5 in the casing 2 so as to correspond to the process units 33 provided for different colors. A plurality (four) are provided and fixed to the casing 2. The scanner units 34 are arranged above the process units 33 and are arranged in parallel at intervals in the casing 2 so as to overlap in the vertical direction. Accordingly, the process units 33 and the scanner units 34 are alternately arranged in the casing 2 along the vertical direction.

Then, as shown in FIG. 10, the scanner unit 34 sequentially passes the laser beam based on the image data emitted from the laser emitting unit through the polygon mirror 47, the two lenses 48, and the reflecting mirror 49 as indicated by arrows. Alternatively, the light is reflected and irradiated on the surface of the photosensitive drum 39 by high-speed scanning as described above.
c. As shown in FIG. 9, the transfer unit 35 is provided between each process unit 33 and the back surface 7 so as to face each process unit 33 arranged in parallel in the vertical direction in the casing 2. It has been. The transfer unit 35 includes an intermediate transfer unit 65 and a belt cleaner unit 51.

The intermediate transfer unit 65 is provided along the vertical direction so as to face the photosensitive drums 39 arranged in parallel along the vertical direction, and is disposed at the center in the front-rear direction of the casing 2. The intermediate transfer unit 65 includes a driving roller 67, a driven roller 66, a transfer belt 68, a primary transfer roller 69, and a secondary transfer roller 70.
The drive roller 67 is disposed above the photosensitive drum 39 of the uppermost black process unit 33K. The driven roller 66 is disposed below the photosensitive drum 39 of the lowest yellow process unit 33Y.

The transfer belt 68 is made of conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed, and is wound between a driving roller 67 and a driven roller 66. The transfer belt 68 is arranged so that the front outer surface in a wound state is in contact with all of the photosensitive drums 39 of the process units 33.
The driven roller 66 is driven by the driving roller 67, and the transfer belt 68 is placed between the driving roller 67 and the two driven rollers 66 on the front outer surface in contact with the photosensitive drum 39 of each process unit 33. Then, it is moved so as to rotate in the same direction as the photosensitive drum 39.

  The primary transfer roller 69 is provided in the wound transfer belt 68 so as to face the photosensitive drum 39 of each process unit 33 with the transfer belt 68 interposed therebetween. The primary transfer roller 69 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The primary transfer roller 69 is disposed so as to be in contact with the front inner surface of the transfer belt 68, and is provided to rotate in the same direction as the circumferential movement direction of the transfer belt 68. A primary transfer bias is applied.

  The secondary transfer roller 70 is provided outside the wound transfer belt 68 and above the drive roller 67 so as to face the drive roller 67 with the transfer belt 68 interposed therebetween. The secondary transfer roller 70 includes a metal roller shaft and a conductive rubber roller covered with the metal roller shaft. The secondary transfer roller 70 is disposed so as to be in contact with the upper surface of the transfer belt 68, and is provided to rotate in the same direction as the circumferential movement direction of the transfer belt 68. A next transfer bias is applied.

The belt cleaner unit 51 has the same configuration as that of the first embodiment, and the cleaning roller 56 is in contact with the rear outer surface of the transfer belt 68 on the opposite side (rear side) of each photosensitive drum 39 in the transfer belt 68. Thus, it is disposed between the drive roller 67 and the driven roller 66.
d. Conveyance Path The conveyance path 36 is located above each process unit 33, halfway between the driving roller 67 and the secondary transfer roller 70 of the intermediate transfer unit 65, and the heating roller 61 and the pressing roller 62 in the fixing unit 37. It is formed as a conveyance path for the sheet 31 from the sheet feed unit 3 to the sheet discharge unit 5 across the space between the sheet feed unit 3 and the sheet discharge unit 5. The transport path 36 does not make a U-turn around the lowermost yellow process unit 33Y as in the first embodiment, and makes a U-turn between the driving roller 67 and the secondary transfer roller 70 in the upper part of the casing 2. It is formed as a short path.

In the transport path 36, a transport roller 60 is provided on the downstream side of the fixing unit 37, and the paper 31 is transported by the transport roller 60.
e. Fixing unit The fixing unit 37 is disposed in the casing 2 obliquely upward and rearward with respect to the secondary transfer position between the driving roller 67 and the secondary transfer roller 70 of the intermediate transfer unit 65. The pressing roller 62 is provided so as to face the conveyance path 36 in the middle.
f. Image Formation in the Engine Unit Then, the sheet 31 fed from the sheet feeding unit 3 is conveyed in a conveyance path 36 so as to make a U-turn between the driving roller 67 and the secondary transfer roller 70.

On the other hand, in the transfer unit 35, the transfer belt 68 is rotated by the drive of the driving roller 67 and the driven roller 66, and each color formed on each photosensitive drum 39 on the transferred transfer belt 68. The toner images are sequentially transferred, whereby a color image is formed on the transfer belt 68.
When the paper 31 passes between the driving roller 67 and the secondary transfer roller 70, the color image formed on the transfer belt 68 is collectively transferred to the paper 3.

Thereafter, the paper 31 on which the color image is formed is thermally fixed in the fixing unit 37 and then conveyed to the paper discharge unit 5.
E. Paper Discharge Unit The paper discharge unit 5 is disposed in the casing 2 on the upper rear side with respect to each process unit 33 of the engine unit 4. The paper discharge unit 5 is disposed to face the paper supply unit 3 with a space in the front-rear direction in the horizontal direction. The paper discharge unit 5 includes a paper discharge roller 63 and a paper discharge holder unit 64.

The paper discharge roller 63 is disposed above the fixing unit 37 and below the paper discharge holder unit 64, and the paper 31 on which the color image is thermally fixed in the fixing unit 37 is directed toward the paper discharge holder unit 64. Eject paper.
The paper discharge holder portion 64 is provided in the casing 2 and is formed as a concave portion having a substantially rectangular shape in front view that can accommodate the paper 31. The discharge holder unit 64 is open on the upper side, and the depth in the vertical direction is set so that the discharged paper 31 is exposed from the upper opening. The paper 31 discharged by the paper discharge roller 63 is held in the vertical direction in the paper discharge holder 64 with the upper end protruding from the casing 2. Further, the discharged paper 31 is stacked along the front-rear direction in the paper discharge holder portion 64.
F. Effects of the Fourth Embodiment In the color laser printer 1 of the fourth embodiment, the paper 31 before color image formation is the process unit 33 of the engine unit 4, more specifically, the uppermost black process unit. It is held along the vertical direction in the paper feed holder 28 of the paper feed unit 3 on the front side above 33K. Further, the paper 31 after the color image is formed is disposed on each process unit 33 of the engine unit 4, more specifically, on the upper rear side of the uppermost black process unit 33 </ b> K. In FIG. Therefore, similarly to the color laser printer 1 of the first embodiment, the installation area can be reduced regardless of the area of the paper 31 while having a plurality of process units 33.

  In the color laser printer 1, each process unit 33 can be attached to and detached from the casing 2 along the front-rear direction by opening the lower cover 12 to open each process unit 33. Therefore, when each process unit 33 is attached or detached, each process unit 33 does not interfere with the paper feed unit 3 and the paper discharge unit 5 disposed above the process unit 33, and each process unit 33 is attached to the casing 2. Can be easily attached and detached.

  Further, in this color laser printer 1, when the upper cover 11 is opened, the paper feed holder portion 28 of the paper feed portion 3 is opened, so that the paper 31 is placed on the paper pressing plate 29 in the paper feed holder portion 28. In addition, it can be set in a laminated form. Further, since the upper cover 11 swings with the upper opening / closing shaft 13 provided along the width direction as a fulcrum, it is compared with the case where the upper cover 11 swings with the upper opening / closing shaft 13 provided along the front-rear direction as a fulcrum. As a result of the opening operation of the upper cover 11, the paper feed holder section 28 of the paper feed section 3 can be opened more widely.

  Further, in this color laser printer 1, since each process unit 33 is opened by opening the lower cover 12, each process unit 33 can be attached and detached independently. Further, since the lower cover 12 swings around the lower opening / closing shaft 14 provided along the width direction as a fulcrum, the lower cover 12 swings around the lower opening / closing shaft 14 provided along the front-rear direction. In contrast, each process unit 33 can be opened more widely by opening the lower cover 12.

  Further, in this color laser printer 1, since the upper cover 11 is disposed above the lower cover 12, the upper cover 11 and the lower cover 12 can be opened and closed independently without interfering with each other. Therefore, the paper supply holder 28 of the paper supply unit 3 can be opened and covered by the opening / closing operation of the upper cover 11, and each process unit 33 is opened independently by the opening / closing operation of the lower cover 12. And can be coated.

In the color laser printer 1, the toner image for each color from the photosensitive drum 39 of each process unit is primarily transferred and superimposed on the transfer belt 68 in the intermediate transfer unit 65, and the superimposed color image is Secondary transfer is performed collectively on the paper 31. Therefore, an intermediate transfer tandem type apparatus configuration can be obtained.
Further, in the color laser printer 1, the conveyance path 36 is arranged above each process unit 33 and formed as a short path, so that it is possible to facilitate jam processing in the conveyance path 36.

1 is a front perspective view showing a first embodiment of a color laser printer as an image forming apparatus of the present invention. It is a principal part block diagram which shows the height adjustment mechanism part of the color laser printer shown in FIG. It is a sectional side view of the color laser printer shown in FIG. FIG. 4 is an enlarged side cross-sectional view of a main part of a process unit and a scanner unit shown in FIG. 3. It is a sectional side view which shows 2nd Embodiment of the color laser printer as an image forming apparatus of this invention. FIG. 6 is an enlarged side cross-sectional view of a main part of the process unit and the scanner unit shown in FIG. 5. It is a sectional side view which shows 3rd Embodiment of the color laser printer as an image forming apparatus of this invention. FIG. 8 is an enlarged cross-sectional side view of a main part of the process unit and the scanner unit shown in FIG. 7. It is a sectional side view which shows 4th Embodiment of the color laser printer as an image forming apparatus of this invention. FIG. 10 is an enlarged side cross-sectional view of a main part of the process unit and the scanner unit shown in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color laser printer 2 Casing 3 Paper feed part 5 Paper discharge part 6 Front 7 Rear 8 Upper surface 11 Upper cover 12 Lower cover 13 Upper opening / closing axis 14 Lower opening / closing axis 15 Operation panel 18 Caster 20 Height adjustment mechanism 31 Paper 33 Process Unit 34 Scanner unit 36 Conveyance path 37 Fixing unit 39 Photosensitive drum 50 Transfer belt unit 65 Intermediate transfer unit

Claims (17)

A casing,
A plurality of image forming units arranged in the casing so as to overlap in the vertical direction and forming images of different colors;
A supply unit that is disposed above the image forming unit, holds the recording medium in the vertical direction, and supplies the held recording medium to the image forming unit side;
A discharge unit disposed above the image forming unit, in which images are formed in the plurality of image forming units and discharged from the image forming unit side, and held in the vertical direction;
A width direction moving means for moving the casing only in a stacking direction in which the recording medium is stacked in the supply unit and the discharge unit and in a width direction orthogonal to the vertical direction;
A second cover for covering or opening at least a part of the image forming unit and attaching and detaching the image forming unit to and from the casing;
Each of the image forming units is attached to and detached from the casing along the same direction as a stacking direction in which recording media are stacked in the supply unit and the discharge unit.   The image forming apparatus according to claim 1, further comprising a position changing unit configured to change a position of the casing along a vertical direction. A first cover provided so as to be swingable with respect to the casing, and covering or opening at least a part of the supply unit and the discharge unit;
The second cover is provided to be swingable with respect to the casing,
The image forming apparatus according to claim 1, wherein the first cover is disposed above the second cover.   The image forming apparatus according to claim 3, wherein the first cover and the second cover are arranged on the same side surface of the casing. A second axis provided in the casing along a stacking direction in which recording media are stacked in the supply unit and the discharge unit and a width direction perpendicular to the vertical direction;
5. The image forming apparatus according to claim 1, wherein the second cover is provided to be swingable with respect to the casing with the second shaft as a fulcrum. A first shaft provided in the casing along a stacking direction in which recording media are stacked in the supply unit and the discharge unit and a width direction perpendicular to the vertical direction;
The image forming apparatus according to claim 3, wherein the first cover is provided so as to be swingable with respect to the casing with the first shaft as a fulcrum.   The image forming apparatus according to claim 5, wherein a side surface of the casing opposite to a side surface on which the first cover or the second cover is disposed is formed in a flat shape.   The image forming apparatus according to claim 1, wherein an operation panel is provided on an upper surface of the casing.   In the casing, there is provided a fixing unit that is disposed above the image forming unit and below the discharge unit and fixes the image formed on the recording medium in the image forming unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is characterized. Each of the image forming units includes a photoreceptor on which an electrostatic latent image is formed,
Provided corresponding to each of the image forming units, comprising an exposure unit for exposing the photoreceptor,
The image forming apparatus according to claim 1, wherein each of the image forming units and each of the exposure units are alternately arranged along a vertical direction.   11. The image forming apparatus according to claim 1, wherein the supply unit and the discharge unit are disposed to face each other with an interval in the horizontal direction.   The recording medium supplied from the supply unit is conveyed from above to below, and after turning the lowermost image forming unit, the recording medium is conveyed from below to above toward the discharge unit. The image forming apparatus according to claim 1, further comprising a pass.   The image formation according to any one of claims 1 to 12, further comprising a transport unit that is arranged along a vertical direction so as to face each of the image forming units and transports a recording medium. apparatus.   The image forming apparatus according to claim 13, wherein the transport unit is disposed to face the discharge unit in a vertical direction.   An intermediate transfer unit is disposed along the vertical direction so as to face each of the image forming units, and an image from each of the image forming units is transferred in an overlapping manner, and the transferred image is transferred to a recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The image forming apparatus according to claim 15, wherein the intermediate transfer unit is disposed to face the discharge unit in a vertical direction.   Each said image formation part is attached or detached with respect to the said casing along the curved attachment or detachment path | route along the side surface of the said casing opened and closed by the said 2nd cover. The image forming apparatus according to claim 16.

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