JP5347790B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus including a plurality of image forming units each having a large-capacity toner container, and which can be individually attached/detached in a vertical direction. <P>SOLUTION: A first extremely narrow gap (d) is formed between the toner containers 8 of the image forming units 7 adjacent to each other among the image forming units 7 (7M, 7C, 7Y, 7K), and the adjacent toner containers 8 come close to each other as much as possible in a non-contact state, and also, disposed as a large-sized container. A second distance (f) larger than the size (e) of an optical write head 13 (13b) is formed between a drum kit 44 and a developing kit 45 of the adjacent image forming units 7, and the optical write head 13 (13a, 13b) is supported by a head rotation support arm 50 and moved in a horizontal direction shown by a both-way arrow c in between the recording position (position of the head 13a) on the photoreceptor drum 9 and a retreat position (position of the head 13b) in the second distance (f) so that the vertical movement of the drum kit 44 may not be interrupted on attaching/detaching the image forming unit 7. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus having a large-capacity toner container and having a plurality of image forming units that can be individually attached and detached in the vertical direction.

  2. Description of the Related Art Conventionally, there is an image forming apparatus in which four image forming units for forming an image by electrophotography are sequentially arranged in a multistage manner. In this image forming apparatus, the photosensitive drum is uniformly charged and initialized, an electrostatic latent image is formed on the photosensitive drum by optical writing, the electrostatic latent image is converted into a toner image, and the toner image is converted into a toner image. It is directly or indirectly transferred onto a transfer material such as paper and fixed by a fixing device.

  As an example of such an image forming apparatus, a sheet fed from a sheet feeding cassette is conveyed while being reversed from the front direction to the rear direction, and a sheet on which a toner image is transferred by the direct transfer method is located downstream in the sheet conveyance direction. There has been proposed a so-called S-shaped paper passing method in which the paper is fixed by a fixing unit arranged at the rear of the main body device and the paper after fixing is reversed and discharged in the forward direction (for example, Patent Document 1).

  By the way, the image forming apparatus disclosed in Patent Document 1 forms an image by a direct transfer method while passing a sheet from the front to the rear of the main body apparatus. Therefore, when the sheet is jammed, the image forming apparatus includes a drum kit and a developing kit. The image forming unit must be removed from the paper path.

  When the image forming unit is attached to or detached from the main body apparatus, the image forming unit is moved in the vertical direction. Therefore, before the image forming unit is detached from the main body apparatus, it is necessary to first move the optical writing head disposed on the drum kit. Therefore, the optical writing head is held in a suspended manner by a head support fixed to the upper surface cover, and the optical writing head is moved up and down in accordance with the rotational opening and closing of the upper surface cover with the rear hinge as a fulcrum. Yes.

  Therefore, it is necessary to provide a passage space for the vertical movement of the optical writing head above the optical writing head, and the space for the toner container of the developing kit is narrowed accordingly. Thus, there is a problem that the internal space cannot be effectively used.

  Also, since a so-called face-up paper discharge unit is formed on the rear surface of the main unit, a space is required to attach a paper discharge tray when using it, which requires a long installation area in the front and rear and is easy to use. There was also a problem of not. In particular, since the fixing unit is disposed behind the main body device, there is a problem that maintenance work is difficult when a paper jam occurs in the fixing unit.

  In order to solve such problems, the left and right direction of the main unit is changed to be the front and rear direction, and the paper fed from the paper feeding cassette is reversed and conveyed from the right to the left, and is directly transferred. The sheet on which the toner image has been transferred by this method is fixed at the fixing unit disposed on the left side of the main unit, which is downstream of the sheet conveyance direction, and the fixed sheet is reversed and discharged in the right direction. Has been proposed (for example, see Patent Document 2).

  In this case as well, when the paper is jammed, the image forming unit composed of the drum kit and the developing kit must be removed from the paper path, but in this example, when the front door is opened, the entire paper path can be seen. Since the image forming unit and the optical writing head are held together in the upper separation frame on which the upper surface discharge tray is formed, the sheet passing path jam is easily maintained.

  In addition, since the jam processing generated on the paper feeding side is processed from the side surface, there is an advantage that the jam processing at the fixing unit that generates high heat is easy except for troublesome points. Further, since the face-up paper discharge section is on the left side, handling is easy. Further, there is no need for a space above the optical writing head, and the capacity of the toner container can be increased by effectively using the space.

  Although various improvements can be found in this way, the upper separation frame lifts the image forming unit and the optical writing head, requiring a strong spring and a link mechanism, and the internal mechanism of the main unit is complicated and enlarged. There was a problem to do.

  Therefore, although there is no change in the point that four image forming units are arranged side by side in a multistage manner, the secondary transfer method is used in order to shorten the paper passing path as much as possible by changing the other configurations significantly. Adopted, a system is proposed in which the paper fed from the paper cassette is transported vertically immediately after feeding, the toner image is secondarily transferred, fixed, and discharged to the upper discharge tray. (For example, see Patent Document 3).

  The paper jam of the paper path and the fixing device occurs only on the right side of the main unit. The paper jam restoration and maintenance work is easy.

  The image forming unit is attached and detached by opening the front door and moving from the front to the longitudinal direction of the optical writing head, that is, the front side of the front. Therefore, the mechanism-related parts are reduced and the price can be reduced. Further, the space above the optical writing head can be effectively utilized. Further, when face-up paper discharge is required, there is no problem because the paper is discharged to the upper surface paper discharge tray using the duplex printing apparatus.

JP 2008-076061 A (06-0228) JP 2008-162030 A (06-1013) JP 2008-309931 A (06-1800)

  By the way, the prior art of Patent Document 3 that seems to have solved various problems also has a large work space in the direction before the installation of the main unit because all units are attached and detached in the front direction with the front door opened. A new problem has arisen.

  In addition, even though the space above the optical writing head can be used effectively, it is necessary to provide each unit with a slide-type holding member in order to attach and detach the units in the forward direction with the front door opened. However, there is still a problem that it cannot be said that the space above the optical writing head is effectively used.

In order to solve the above-described problems, an image forming apparatus of the present invention includes first, second, third, and fourth drum kits each including a photosensitive drum, and a space above each drum kit. The first, second, third, and fourth image forming units including the first, second, third, and fourth developing kits that extend are arranged vertically with respect to the main body apparatus so as to be arranged in a multistage manner. detachably mounted in the direction, the first of the first toner container and a second toner container provided continuously to the upper portion of the second developing kit provided continuously on the top of the development kit, said second toner third toner container provided continuously to the top of the container and the third developing kit, and a fourth toner container provided continuously on the top of the third toner container and the fourth developing kit, capital is each Once disposed near a predetermined clearance without intervening the other member co , Between the first drum kit and the second developing kit, between the second drum kit and the third developing kit, and the third drum kit and the fourth developing kit And a lower space formed between the fourth drum kit and the side wall of the main unit, and a lower position away from the predetermined gap , and in a space above each drum kit. each photosensitive member and the recording position for optical writing to each photoreceptor drum in proximity to an upper portion of the drum, the first which is movable into a non-recording position retracted to the respective lower space, second, third and a fourth optical writing head, first moving to the non-recording position each optical writing head from the recording position before the respective image forming units is taken out upward from said main apparatus, the second, third and fourth head turning support arms Characterized in that it has a.

In this image forming apparatus, for example, the head rotation support arm is provided at a lower end of a shaft with a handle that extends between the side surface of each toner container and the other side wall of the main body device and extends above and below the main body device. is connected to the part, in conjunction with the vertical movement of the handle shaft is configured to move the above-described optical writing head to the recording position or the non-recording position.

  According to the present invention, the optical writing head is moved horizontally from the top of the drum kit and the image forming units are individually taken out in the vertical direction, so that only the image forming unit necessary for the work can be taken out, which is convenient. There is an effect.

  Further, since the image forming unit is taken out in the vertical direction, there is no need for a slide-type support portion, and the toner containers can be arranged as close as possible so that adjacent toner containers are not in contact with each other using an empty space. There is an effect that the size can be increased.

1 is a cross-sectional view illustrating an internal configuration of a full-color image forming apparatus (printer) according to Embodiment 1 of the invention. FIG. 3 is a diagram illustrating a positional relationship between an image forming unit and an optical writing head of the printer according to the first embodiment of the invention. FIG. 5 is a diagram illustrating a specific operation mechanism of the optical writing head when the image forming unit of the printer according to the first exemplary embodiment of the present invention is attached or detached.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a cross-sectional view illustrating the internal configuration of a full-color image forming apparatus (printer) according to a first embodiment of the invention.

  A printer 1 shown in FIG. 1 is an electrophotographic secondary transfer tandem color image forming apparatus, and includes an image forming unit 2, a belt unit 3, a paper feeding unit 4, a belt type fixing device 5, and double-sided printing. The transport unit 6 is used.

  The image forming unit 2 arranges four image forming units 7 (7M, 7C, 7Y, 7K) which are first, second, third and fourth units from right to left in FIG. It consists of a set up structure.

  Of the four image forming units 7, three image forming units 7M, 7C, and 7Y on the upstream side (right side in the figure) are magenta (M), cyan (C), and yellow (subtractive three primary colors, respectively). A mono-color image is formed using the color toner of Y), and the image forming unit 7K forms a monochrome image using black (K) toner mainly used for dark portions of characters and images.

  Each of the image forming units 7 has the same configuration except for the color of toner stored in a toner container (toner cartridge) 8. Therefore, the configuration of the image forming unit 7 will be described below by taking the image forming unit 7K for black (K) as an example.

  The image forming unit 7 includes a photosensitive drum 9 at the bottom. The photosensitive drum 9 has a peripheral surface made of, for example, an organic photoconductive material. A cleaner 11, a charging roller 12, an optical writing head 13, and a developing roller 15 of a developing device 14 are arranged around the periphery of the photosensitive drum 9.

  The developing unit 14 is connected to the toner container 8 provided at the upper portion thereof, as shown by M, C, Y, and K in the drawing, for magenta (M), cyan (C), yellow (Y), and black (K). One of the toners is accommodated, and a toner replenishing mechanism for the lower part is provided in a connecting portion with the toner container 8.

  Further, the developing roller 15 is provided in the lower side of the developing unit 14 at the side opening, and a toner stirring member, a toner supply roller 16 for supplying toner to the developing roller 15, and a toner layer on the developing roller 15 are fixed. A doctor blade that regulates the layer thickness is provided.

  The belt unit 3 has an endless intermediate transfer belt 17 extending in a flat loop shape from substantially the left and right sides of the figure in the approximate center of the main unit, and an intermediate transfer belt 17 that is stretched over the intermediate transfer belt 17. A driving roller 18 and a driven roller 19 are provided to circulate and move the transfer belt 17 in the counterclockwise direction in the figure.

  The intermediate transfer belt 17 transfers the toner image directly to the belt surface (primary transfer), and conveys the toner image to a transfer position to the paper for further transfer (secondary transfer) to the paper.

  The belt unit 3 includes a belt position control mechanism (not shown) in the loop of the flat loop-shaped intermediate transfer belt 17. The belt position control mechanism includes a primary transfer roller 21 made of a conductive foam sponge that presses the lower peripheral surface of the photosensitive drum 9 via the intermediate transfer belt 17.

  The belt position control mechanism 17 includes three primary transfer rollers 21 corresponding to the three image forming units 7M, 7C, and 7Y of magenta (M), cyan (C), and yellow (Y). Rotate and move around the support shaft at the same period.

  Then, the belt position control mechanism rotates and moves one primary transfer roller 21 corresponding to the black (K) image forming unit 7K at a rotational movement cycle different from the cycle of the three primary transfer rollers 21. The belt 17 is moved away from the photosensitive drum 9.

  That is, the belt position control mechanism adjusts the position of the intermediate transfer belt 17 of the belt unit 3 to a full color mode (all four primary transfer rollers 21 are in contact with the intermediate transfer belt 17) and a monochrome mode (corresponding to the image forming unit 7K). Only the primary transfer roller 21 in contact with the intermediate transfer belt 17) and the all non-transfer mode (all four primary transfer rollers 21 are separated from the intermediate transfer belt 17).

  In the belt unit 3, a belt surface sensor 24 is disposed further downstream of the image forming unit 7 </ b> K on the most downstream side in the belt movement direction on the upper surface portion. Further, a belt cleaner unit 22 is disposed further upstream of the most upstream image forming unit 7M, and a flat and thin waste toner collecting container 23 is detachably disposed so as to be substantially along the entire bottom surface. Yes.

  The belt cleaner unit 22 abuts on the upper surface of the intermediate transfer belt 17 to scrape and remove the waste toner, and collects the waste toner in a temporary storage unit (not shown). It is conveyed to the upper part and sent to the waste toner collecting container 23 via a dropping cylinder.

  The paper feed unit 4 includes two paper feed cassettes 25 (25a, 25b) for narrow paper and large paper, which are arranged in two upper and lower stages, and the paper feed ports (shown in the drawing) of the two paper feed cassettes 25. In the vicinity of the right side, a sheet take-out roller 26, a feeding roller 27, and a separating roller 28 are provided, respectively, and a standby conveyance roller pair 29 is disposed on the downstream side with the sheet conveyance direction facing upward.

  A secondary transfer roller 31 that is in pressure contact with the driven roller 19 via the intermediate transfer belt 17 is disposed in the sheet conveyance direction (vertical upward direction in the figure) of the standby conveyance roller pair 29, and a secondary transfer unit to the sheet. Is forming.

  In the paper conveyance path 32 continuing downstream (upward in the drawing) of the secondary transfer portion, the back surface of the paper is strong enough not to resist the conveyance force of the secondary transfer portion so as not to damage the unfixed toner image. An adsorbing portion 33 that adsorbs at is arranged.

  A belt-type fixing device 5 is disposed downstream of the sheet conveyance path 32. In the belt-type fixing device 5, two heating / pressure rollers 34 (34a, 34b) are pressed against each other via a fixing belt 35 (35a, 35b) to form a fixing portion.

  The fixing belt 35 is stretched between a heating roller 36 (36a, 36b) having a built-in heater and a heating / pressure roller 34, and transmits heat received from the heating roller 36 to the heating / pressure roller 34. In cooperation with the heating / pressure roller 34, the toner image of the paper carried into the fixing unit is heated.

  On the further downstream side of the belt-type fixing device 5, a pair of carry-out rollers 37 for carrying out the paper on which the toner image has been fixed from the belt-type fixing device 5 and a paper discharge tray 38 formed on the upper surface of the device. A paper discharge roller pair 39 for paper discharge is provided.

  The duplex printing conveyance unit 6 extends from the conveyance path in the middle between the carry-out roller pair 37 and the paper discharge roller pair 39 to the start return path 41a branched rightward in the figure, and then bent downward and extends vertically. An intermediate return path 41b, a terminal return path 41c that bends in the left lateral direction opposite to the above and finally reverses the return sheet, and four sets of return roller pairs 42a and 42b arranged in the middle of these return paths. , 42c, 42d.

  The exit of the end return path 41 c communicates with a conveyance path to the standby conveyance roller pair 29 corresponding to the sheet feeding cassette 25 a above the sheet feeding unit 4. Another return roller pair 43 is arranged on the transport path from the exit of the end return path 41 c to the standby transport roller pair 29.

  In the printer 1, the right side shown in the figure is the front of the main unit and the left side is the rear. The paper feed cassette 25 of the paper feed unit 4 is inserted and removed in the direction of the arrow a from the front of the main unit and is attached and detached. Further, the sheet is conveyed substantially vertically upward along the inside of the duplex printing conveyance unit 6 disposed on the right end surface of the main body apparatus.

  Therefore, if a paper jam occurs during the paper feeding, secondary transfer, fixing, and paper discharge operations, the paper jam occurs at a position along the inside of the duplex printing transport unit 6. When a paper jam occurs, maintenance work is possible by rotating the duplex printing conveyance unit 6 that also serves as the front door as shown by the arrow b and opening it to the position of the broken line 6 '.

  The image forming unit 7 is a consumable item that is replaced with a new one when the specified life is reached. The drum kit 44 and the developing kit 45 are detachably integrated with the unit frame. Yes.

  The drum kit 44 is configured by integrally assembling a photosensitive drum 9, a cleaner 11, a charging roller 12, and the like to a drum kit frame. The development kit 45 includes a development unit 14 including a development roller 15, a toner supply roller 16, a doctor blade, and the like, and a toner container 8 and the like that are continuously provided on the development unit 14, and are integrally assembled in the development kit frame. Has been.

  Although not specifically shown, the image forming unit 7 is detachably engaged with a guide groove provided on the front and rear inner walls of the main body device in a vertical direction. When mounted on the main unit, it is positioned by the guide groove and locked to a fixing member (not shown) to be fixed to the main unit.

  FIG. 2 is a diagram for explaining the positional relationship between the image forming unit 7 and the optical writing head 13. 2 shows the first, second, and third image forming units 7 (7M, 7C, and 7Y, where the third image forming unit 7Y has only the right half), the optical writing head 13, An intermediate transfer belt 17 and a belt cleaner unit 22 are shown.

  As shown in FIG. 2, in the first, second, third, and fourth image forming units 7, the toner container 8 and the toner container 8 that are connected to the upper part of the developing kit 45 of the adjacent image forming unit 7 A first gap d is formed between them so that the adjacent toner containers 8 do not come into contact with each other. In other words, the adjacent toner container 8 and the toner container 8 are arranged as close as possible so as not to contact each other.

  A second interval f larger than the dimension e of the optical writing head 13 (see 13b) is formed between the drum kit 44 and the developing kit 45 of the adjacent image forming unit 7. Note that there is no developing kit for the adjacent image forming unit next to the drum kit 44 of the fourth image forming unit 7K (not shown), and instead, the side wall of the main unit is located (see FIG. 1). Is formed with a second interval f (above the belt surface sensor 24).

  The optical writing head 13 (13a, 13b) is a recording position (optical recording) for forming an electrostatic latent image on the photosensitive drum 9 so as not to prevent the vertical movement of the drum kit 44 when the image forming unit 7 is attached or detached. As shown by a double-headed arrow c, it moves in the horizontal direction between the position of the insertion head 13a) and the retracted position of the second gap f (position of the optical writing head 13b).

  That is, when the image forming unit 7 is attached or detached, the optical writing head 13 moves from the recording position to the retracted position before the image forming unit 7 is taken out from the main body apparatus. Then, the optical writing head 13 returns from the retracted position of the second gap f to the recording position on the upper surface of the photosensitive drum after the taken image forming unit 7 returns to the recording position from above.

  FIG. 3 is a diagram for explaining a specific operation mechanism for the optical writing head 13 to operate as described above when the image forming unit 7 is attached / detached. In FIG. 3, the second image forming unit 7C is typically shown together with the intermediate transfer belt 17 and the primary transfer roller 21.

  As shown in FIG. 3, it passes between the side surface of the toner container 8 and the inner wall of the side surface of the main body (the side facing the front side in FIG. 3, but not shown). A shaft 46 is provided.

  A handle 47 is attached to the upper end of the shaft 46 with handle, and one end of a connecting rod 49 is engaged with the lower end of the shaft 46 with handle via a hinge 48. The other end of the connecting rod 49 is engaged with the lower end of the head rotation support arm 50 via the rotation fulcrum 51. The head rotation support arm 50 supports the optical writing head 13 (13a, 13b) via the support shaft 52 at its upper end.

  When the user replaces the image forming unit 7, the user first raises the handle 47 in the upward direction indicated by the vertical arrow g and to the position indicated by the broken line 47 '. Along with this pulling up, the shaft 46 with handle rises.

  In response to the ascent of the shaft 46 with handle, the connecting rod 49 connected to the lower end of the shaft 46 with handle via the hinge 48 has the rotation fulcrum 51 as a fulcrum in the counterclockwise direction indicated by the bi-directional arc arrow h. To the position indicated by the broken line 49 '.

  Along with the rotation of the connecting rod 49, the head rotating support arm 50 that is integral with the connecting rod 49 via the rotation fulcrum 51 supports the optical writing head 13 a via the support shaft 52, in both directions. It rotates in the counterclockwise direction indicated by the arc arrow i to the position indicated by the broken line 50 '.

  By this rotation, the optical writing head 13a at the recording position moves to the position of the optical writing head 13b in the second gap f (see FIG. 2) which is the retracted position. Thus, by removing the member that prevents the drum kit 44 from moving upward, the user can pull the image forming unit 7C upward as indicated by the arrow j.

  In exchange for this, when the user installs a new image forming unit 7C, the new image forming unit 7C is mounted in the opposite direction indicated by the arrow j from the top to the bottom after the previously-drawn image forming unit 7C. To do.

  Thereafter, the handle 47 at the position of the broken line 47 ′ is pushed down to the position indicated by the solid line in the downward direction indicated by the up and down arrow g. The handle shaft 46 is lowered, and the connecting rod 49 engaged with the lower end of the shaft rotates from the position indicated by the broken line 49 ′ in the clockwise direction indicated by the bidirectional arc arrow h at the solid line position.

  As a result of this rotation, the head rotation support arm 50 supports the optical writing head 13b via the support shaft 52, and moves from the position indicated by the broken line 50 'to the clockwise direction indicated by the bidirectional arc arrow i. Rotate until

  By this rotation, the optical writing head 13b in the retracted position moves to the position of the optical writing head 13a that is the recording position. Thus, the position of the optical writing head 13a is fixed at the recording position on the drum kit 44, and recording can be resumed by exposure to the photosensitive drum 9.

  The above-described attachment / detachment of the image forming unit 7 has been described mainly with the second image forming unit 7C as the center in the above example, but the other first, third, and fourth image forming units 7M, 7Y, The same applies to 7K.

  As described above, according to the embodiment of the present invention, the optical writing head 13 is moved horizontally from above the drum kit 44 and the image forming units 7 are individually taken out in the vertical direction. The effect that it is convenient to be able to take out only is produced.

  Further, since the image forming unit 7 is taken out in the vertical direction, there is no need for a slide-type support portion for taking out in the horizontal direction, and the adjacent toner containers 8 can be arranged so as not to contact each other using the empty space. As a result, the toner container 8 can be enlarged as much as possible.

  The present invention can be used in an image forming apparatus having a large capacity toner container and having a plurality of image forming units that can be individually attached and detached in the vertical direction.

DESCRIPTION OF SYMBOLS 1 Printer 2 Image formation part 3 Belt unit 4 Paper feed part 5 Belt type fixing device 6 Duplex printing conveyance unit 7 (7M, 7C, 7Y, 7K) Image formation unit 8 Toner container (toner cartridge)
DESCRIPTION OF SYMBOLS 9 Photosensitive drum 11 Cleaner 12 Charging roller 13 Optical writing head 14 Developing device 15 Developing roller 16 Toner supply roller 17 Intermediate transfer belt 18 Drive roller 19 Driven roller 21 Primary transfer roller 22 Belt cleaner unit 23 Waste toner collection container 24 Belt surface Sensor 25 (25a, 25b) Paper feed cassette 26 Paper take-out roller 27 Feed roller 28 Rolling roller 29 Standby conveyance roller pair 31 Secondary transfer roller 32 Paper conveyance path 33 Adsorption part 34 (34a, 34b) Heating / pressure roller 35 (35a, 35b) Fixing belt 36 (36a, 36b) Heat generating roller 37 Unloading roller pair 38 Discharging tray 39 Discharging roller pair 41a Start returning path 41b Intermediate returning path 41c End returning path 42a, 42b, 42c, 42d Returning roller pair 43 Other return Roller pair 44 Drum Kit 45 developing kit d first gap e dimensions f the second interval 46 with a handle shaft 47 handles the optical writing head 48 hinge 49 coupling rod 50 head turning support arms 51 pivot point 52 the support shaft

Claims (2)

First, second, third, and fourth drum kits each including a photosensitive drum, and first, second, third, and fourth developments having spaces above each drum kit, respectively. The first, second, third and fourth image forming units comprising the kit are detachably provided in the vertical direction with respect to the main body device so as to be sequentially arranged in a multistage manner .
First second toner container provided continuously on the top of the toner container and the second developing kit, the third developing said second toner container provided continuously on the top of the first development kit third toner container, and a fourth toner container provided continuously on the top of the third toner container and the fourth developing kit provided continuously to the upper part of the kit, capital mediated other members respectively It is arranged in close proximity with a predetermined gap without anything,
Between the first drum kit and the second development kit, between the second drum kit and the third development kit, and between the third drum kit and the fourth development kit. And a lower space formed between the fourth drum kit and the side wall of the main unit, respectively .
Wherein provided on the lower position away from the predetermined gap, and a recording position where the proximate the top of the respective photosensitive drums in the space above the respective drum kit performs optical writing on the respective photosensitive drums, wherein each the first which is movable into a non-recording position retracted into the lower space of the second, third and fourth optical writing head,
First moving the respective optical writing head before the image forming units is taken out upward from the main device to the non-recording position from the recording position, the second, third and fourth head rotation support Arms,
An image forming apparatus comprising: Each of the head rotation support arms is connected to a lower end portion of a shaft with a handle that passes between a side surface of each of the toner containers and another inner wall of the main body device and extends up and down the main body device. 2. The image forming apparatus according to claim 1, wherein each of the optical writing heads is moved to the recording position or the non-recording position in conjunction with a vertical movement of the shaft.