JP2013047840A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in image density even when used over a long period of time by suppressing rising of temperature while obtaining higher speed and down sizing in an apparatus.SOLUTION: An image forming apparatus comprises: a plurality of process cartridges 7 in which photoreceptor drums 1 and process means affecting the photoreceptor drums 1 are integrally composed; an intermediate transfer unit 13 with an intermediate transfer belt 13A installed in contact with the plurality of photoreceptor drums 1; and an air blowing fan 41 blowing air inside the apparatus. In the image forming apparatus, projections 61 and grooves 62 are formed so as to be mutually engaged on an outer wall of the process cartridges 7. The air blowing fan 41 sends air to an air path formed by space 67 between one of the projections 61 of the plurality of the process cartridges 7, the groove 62 in the process cartridge 7 adjacent to the projection 61 and the process cartridge 7.

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile.

  There is an image forming apparatus that employs a tandem color image forming system. A tandem type color image forming apparatus generally requires an increase in the number of driving units and an accompanying increase in power supply size. Also in the fixing device, the toner must be mixed on the transfer material and then fixed on the transfer material, and the amount of heat generated in the fixing unit increases.

  For this reason, a configuration has been proposed in which heat in the fixing unit is not transmitted to the image forming unit (see, for example, Patent Document 1). In addition, a configuration has been proposed in which the chassis of the image forming apparatus is divided into a first chassis that forms an image forming portion and a second chassis dedicated to fixing (for example, see Patent Document 2). As described above, conventionally, the problem has been solved by designing the heat so that the heat from the fixing unit is not transmitted to the image carrier or the image forming unit.

  However, a tandem color image forming apparatus that will increase in speed in the future needs to actively exhaust heat generated from the image forming unit. In addition, it is necessary to design the heat in consideration of various viewpoints with respect to the temperature rise in the apparatus main body including the image forming unit.

  On the other hand, the configuration of the color image forming apparatus is roughly divided into two configurations depending on the insertion / extraction direction of the process cartridge (image carrier unit). FIG. 6 is an explanatory diagram of the configuration of the color image forming apparatus. One is a configuration in which the process cartridge is inserted and removed in a direction parallel to the sheet conveying direction in the apparatus as shown in FIG. The other is a configuration in which the process cartridge is inserted and removed in a direction crossing the sheet conveying direction in the image forming apparatus as shown in FIG. The latter configuration is also called a side-oriented configuration.

  In the case of a color image forming apparatus, since a plurality of image forming units (generally four colors) are used, the volume occupied by the image forming unit in the entire apparatus also increases. Here, considering the ease of operation by the user, the latter configuration that can set the distance between the user and the process cartridge to be accessed closer is considered advantageous, and has become the main product form of a color image forming apparatus. ing. The latter configuration is a configuration in which the process cartridge can be attached and detached while the image reading unit on the upper surface of the apparatus is fixed, and is effective even in consideration of a multi-function color printer. The multi-function color printer has an image reading unit arranged on the upper part of a color image forming apparatus, and can easily perform color copying on a desk.

JP 2004233345 A JP 2005-292564 A

  However, in recent years, tandem color image forming apparatuses have been reduced in size and increased in output speed, so it is difficult to ensure a sufficient clearance between the image forming unit and the heat source and to reduce the recording throughput. . For this reason, the temperature of the image forming unit exceeds the allowable temperature, and the image is stably formed on the image carrier by fixing the toner in the toner container and the temperature rises, and the toner image formed on the image carrier is transferred to the transfer material. It is difficult to transfer reliably.

  Also, the temperature of the transfer belt portion arranged along the image carrier rises, and the running speed of the belt surface becomes unstable due to the change in the diameter of the roller driving the transfer belt and the belt thickness, resulting in color misregistration between colors. It sometimes occurred.

  Further, the life of color image forming apparatuses has been extended, and it has become necessary to guarantee printed images even after long-term use. As a representative example of image deterioration during long-term use, there is a decrease in the density of a recorded image caused by contamination with toner as a developer. This is a phenomenon in which toner that falls and floats from the developing unit in the image forming unit into the apparatus enters the exposure optical path and blocks the optical path. In general, the exposure means for performing latent image exposure has a cover glass, and it is considered that there is a risk of toner adhesion most on the cover glass. Therefore, in order to prevent the above-described decrease in density, it is necessary to devise a configuration in which toner does not adhere to the cover glass. In addition, in the side-oriented configuration which is a mainstream product form of a color image forming apparatus, it is necessary to set an optimal cooling means and air flow for solving the heat problem.

  An object of the present invention is to suppress an increase in temperature and achieve a reduction in image density even when used for a long period of time while achieving speeding up and downsizing of the apparatus.

A typical configuration according to the present invention for achieving the above object is as follows:
A plurality of image carrier units integrally configured with an image carrier and process means acting on the image carrier; and a transfer belt unit having an endless belt disposed so as to be in contact with the plurality of image carriers; An image forming apparatus having air blowing means for sending air into the apparatus,
A protrusion and a groove are formed on the outer wall of the image carrier unit so as to mesh with each other.
The blowing unit is formed in a space between one of the plurality of image carrier units, the groove of the image carrier unit adjacent to the projection, and the transfer belt unit. It is characterized by sending air to the wind path.

  With the above-described configuration, it is possible to suppress the temperature rise while achieving high speed and downsizing of the apparatus and not to reduce the image density even when used for a long time.

  The present embodiment will be described in detail with reference to the drawings.

[Entire configuration of image forming apparatus]
First, the overall configuration of the image forming apparatus will be outlined with reference to FIG. FIG. 1 is a longitudinal sectional view showing an overall configuration of a color laser printer 100 which is an embodiment of an image forming apparatus.

  A color laser printer 100 shown in FIG. 1 has a plurality (four in this embodiment) of photosensitive drums 1a, 1b, 1c, and 1d that are image carriers (hereinafter, subscripts a to d are appropriately omitted). explain). Around each photosensitive drum 1, a charging unit 2, an exposure unit 3, a developing unit 4 as a developing unit, a primary transfer roller 12, and a drum cleaning blade 8 as a cleaning unit are arranged in order according to the rotation direction. The

  Here, the charging means 2 (2a, 2b, 2c, 2d) uniformly charges the surface of the photosensitive drum 1. The exposure unit 3 irradiates a laser beam based on the image information to form an electrostatic latent image on the photosensitive drum 1. The developing unit 4 (4a, 4b, 4c, 4d) causes toner to adhere to the electrostatic latent image to be visualized as a toner image. The intermediate transfer unit 13 uses the primary transfer roller 12 (12a, 12b, 12c, 12d) to transfer the toner image on the photosensitive drum 1 to an intermediate transfer belt (endless belt) 13A. The drum cleaning blade 8 (8a, 8b, 8c, 8d) removes post-transfer toner remaining on the surface of the photosensitive drum 1 after transfer.

  In this embodiment, in addition to the photosensitive drum 1, a charging unit 2, a developing unit 4, and a drum cleaning blade 8 are integrally formed into a cartridge, thereby forming a process cartridge 7 as an image carrier unit. The plurality of process cartridges 7 (7a, 7b, 7c, 7d) are configured to be detachable from the color laser printer 100. The process cartridge is configured so as to integrally include either the photosensitive drum 1 or a process unit (charging unit, developing unit, cleaning unit, etc.) that acts on the photosensitive drum 1.

  These four process cartridges 7 have the same structure, but are different in that they form images with different color toners. Yellow (Y), magenta (M), cyan (C), and black (Bk) are formed corresponding to the subscripts a, b, c, and d, respectively. The process cartridge 7 includes a developing unit 4 and a cleaner unit 5 (5a, 5b, 5c, 5d).

  Among them, the developing unit 4 includes a developing roller 24 (24a, 24b, 24c, 24d) for attaching a developer to the photosensitive drum 1, a developer applying roller 25 (25a, 25b, 25c, 25d), and a toner container. Have. On the other hand, the cleaner unit 5 includes a photosensitive drum 1, a charging unit 2, a drum cleaning blade 8, and a waste toner container.

  The photosensitive drum 1 is configured by applying an organic photoconductive layer (OPC) to the outer peripheral surface of an aluminum cylinder. Both end portions thereof are rotatably supported by flanges, and a driving force is transmitted to one end portion from a driving motor (not shown). Thereby, it is rotationally driven in the clockwise direction shown by the arrow in FIG.

  The charging means 2 is a conductive roller formed in a roller shape, and this roller is brought into contact with the surface of the photosensitive drum 1. At the same time, the surface of the photosensitive drum 1 is uniformly charged by applying a charging bias voltage from a power source (not shown).

  The exposure unit 3 is arranged vertically below the process cartridge 7 and performs exposure based on the image signal to the photosensitive drum 1.

  The developing unit 4 has a storage unit that stores toner (developer) of each color of yellow (Y), magenta (M), cyan (C), and black (Bk). Further, the image forming apparatus includes a developing roller that is adjacent to the surface of the photosensitive member, is driven to rotate by a driving unit (not shown), and performs development by applying a developing bias voltage from a developing bias power source (not shown).

  With the configuration described above, an electrostatic latent image is formed on each photosensitive drum 1 by the exposure unit 3 after being charged to a predetermined negative potential by the charging unit 2. The electrostatic latent image is reversely developed by the developing unit 4 and negative toner is attached to form Y, M, C, and Bk toner images.

  In the intermediate transfer unit (transfer belt unit) 13, an intermediate transfer belt 13A is stretched around a drive roller 13B and a tension roller 13C, and the tension roller 13C applies tension in the direction of arrow E. Further, a primary transfer roller 12 is disposed inside the intermediate transfer belt 13A so as to face each photosensitive drum 1, and a transfer bias is applied by a bias applying unit (not shown).

  When the intermediate transfer belt 13A is rotated in the direction of the arrow F and a positive bias is applied to the primary transfer roller 12, the toner image on the photosensitive drum 1a to the toner image on the photosensitive drum 1d are sequentially transferred to the intermediate transfer belt. Primary transferred onto 13A. Then, the four color toner images are conveyed to the secondary transfer unit 15 in a state where they overlap.

  The feeding device 10 includes a feeding roller 9 that feeds the sheet S from within a feeding cassette 11 that stores the sheet S that is a transfer material, and a conveyance roller pair 10A that conveys the fed sheet S. ing.

  The feeding cassette 11 is configured so that it can be pulled out toward the front side of the main body in FIG. 1. After the user pulls out the feeding cassette 11 and removes it from the apparatus main body, the sheet S is set and inserted into the apparatus main body. This completes the sheet supply.

  The sheets S stored in the feeding cassette 11 are pressed against the feeding roller 9, separated one by one by the separation pad 23 (friction piece separation method), and conveyed.

  Then, the sheet S conveyed from the feeding device 10 is conveyed to the secondary transfer unit 15 by the registration roller pair 17.

  In the secondary transfer unit 15, a positive bias is applied to the secondary transfer roller 16, whereby the four color toner images on the intermediate transfer belt 13 </ b> A are secondarily transferred to the conveyed sheet S.

  The fixing unit 14 serving as a fixing unit applies heat and pressure to an image formed on a sheet and fixes the image. The fixing unit 14 includes a cylindrical fixing belt 14A, an elastic pressure roller 14B, and a belt guide member 14C in which a heating unit such as a heater is bonded to the fixing belt 14A. The elastic pressure roller 14B sandwiches the fixing belt 14A and forms a fixing nip portion N having a predetermined width with a predetermined pressure contact force with the belt guide member 14C.

  The pressure roller 14B is rotationally driven by a driving unit (not shown), and the cylindrical fixing belt 14A rotates accordingly, and the fixing belt 14A is heated by an internal heater (not shown).

  In a state where the fixing nip N rises to a predetermined temperature and is adjusted in temperature, the sheet S on which the unfixed toner image conveyed from the image forming unit is formed is fixed to the fixing belt 14A and the pressure roller 14B of the fixing nip N. Introduced between. When the image surface of the sheet S is introduced upward, that is, facing the fixing belt surface, the image surface of the sheet S is nipped and conveyed in the fixing nip portion N while being in close contact with the outer surface of the fixing belt 14A. .

  In the process in which the sheet S is nipped and conveyed together with the fixing belt 14A through the fixing nip N, the heater heat in the fixing belt 14A is heated and the unfixed toner image on the sheet S is heated and fixed. The fixed sheet S is discharged to the discharge tray by the discharge roller pair 20.

  On the other hand, the toner remaining on the surface of the photosensitive drum 1 after the toner image transfer is removed by the cleaning blade 8. The removed toner is collected in a waste toner container in the cleaner unit 5.

  Further, the toner remaining on the intermediate transfer belt 13A after the secondary transfer onto the sheet S is removed by the transfer belt cleaning device 18. The removed toner passes through a waste toner conveyance path (not shown) and is collected in a waste toner collection container (not shown) disposed on the back surface of the apparatus.

[Process cartridge installation / removal configuration]
Next, the attachment / detachment configuration of the process cartridge 7 in the tandem type color image forming apparatus will be described in detail. FIG. 2 is a perspective view showing a method for attaching / detaching the process cartridge 7 and a structure for attaching / detaching the feeding cassette 11. FIG. 3 is a cross-sectional view showing the attachment / detachment configuration of the process cartridge 7 and the air passage configuration.

  In the tandem type color image forming apparatus, replenishment of the sheet to the feeding cassette 11, attachment / detachment of the process cartridge 7, and collection of the printed sheet S can be operated from the front side of the apparatus. Further, the process cartridge can be attached and detached in the drum axis direction and on the front side of the apparatus. The detachable configuration of this embodiment is a side-oriented configuration that is one of the mainstream in color image forming apparatuses.

  As shown in FIG. 3, a partition plate 32 that partitions the arrangement area of the process cartridge 7 and the exposure means 3 is disposed in the apparatus main body. The partition plate 32 has opening holes 30 (30a, 30b) for forming the optical path of the exposure means 3. An insertion guide 21 (21a, 21b) is formed in the vicinity of the opening hole 30 (30a, 30b).

  With this configuration, the user inserts the insertion rib 22 (22a, 22b) formed integrally with the process cartridge 7 along the insertion guide 21 (21a, 21b). Thereby, the process cartridge 7 can be easily mounted at a predetermined position of the apparatus main body.

  When positioning the process cartridge 7 in the image forming apparatus, a boss (not shown) formed on the process cartridge 7 is fitted into a hole (not shown) of the apparatus main body. As a result, the process cartridge 7 is positioned in the image forming apparatus. In this state, the insertion rib 22 (22a, 22b) and the insertion guide 21 (21a, 21b) are not in contact with each other.

[Configuration for preventing deterioration of developing roller and photosensitive drum]
In this embodiment, a mechanism for separating the developing roller 24 (24a, 24b) from the photosensitive drum 1 (1a, 1b) is adopted except for the time of development in order to suppress the deterioration of the developing means. Specifically, the contact / separation state is created as follows.

  First, at the time of image formation, as shown in FIG. 3A, the developing roller 24 is in contact with the photosensitive drum 1 by a pressing means (not shown) (first state). On the other hand, at the time of non-image formation (when the developing roller is separated), as shown in FIG. 3 (b), centering on the swing center X (Xa, Xb) provided in the cleaner unit 5 (5a, 5b) The developing unit 4 swings counterclockwise in FIG. Since the developing roller 24 (24a, 24b) is supported by the developing unit 4 (4a, 4b), the developing roller 24 (24a, 24b) is separated from the photosensitive drum 1 (second state). Thus, a contact / separation state between the developing roller 24 and the photosensitive drum 1 is created.

  Further, as shown in FIG. 3, projecting portions 61 (61a, 61b) projecting in a convex shape are integrally formed with the container of the developing device 4 (4a, 4b) on the outer wall of the developing device 4 (4a, 4b). It is formed. For example, the protrusion 61b is disposed so as to enter the cleaner unit 5a of the process cartridge 7a disposed adjacent thereto. In order to avoid interference between the process cartridge 7a and the process cartridge 7b, concave grooves 62 (62a, 62b) are provided integrally with the cleaner unit 5 on the outer wall of the cleaner unit 5a of the process cartridge 7a.

[Configuration of the substantially closed space 67]
As shown in FIG. 3A, the upper surface 63b of the protruding portion 61b is arranged so as to ensure a 2 mm clearance from the inner surface 64a of the groove 62a provided in the adjacent cleaner unit 5a. Then, as shown in FIG. 3A, during image formation, a substantially closed space 67 (hatched area) partitioned by the intermediate transfer belt 13A and the outer wall of the adjacent process cartridge 7 (7a, 7b). Can do. Thus, by forming the protrusion 61 and the groove 62 in the process cartridge, the substantially closed space 67 formed around the cartridge is separated from the optical path areas 68a and 68b of the process cartridges 7a and 7b.

  Further, as shown in FIG. 3B, during non-image formation (development roller separation state), the lower surface 65b of the protruding portion 61b is 2 mm away from the inner surface 66a of the groove portion 62a provided in the adjacent cleaner unit 5a. Move until it is secured. Then, as in image formation, a substantially closed space 67 can be created as shown in FIG.

  As a result, it is the same whether the developing roller 24 (24a, 24b) is in contact with the photosensitive drum 1 (1a, 1b) or separated from the photosensitive drum 1. Thus, the substantially closed space 67 can be created.

[Air path configuration of the device]
An air path configuration for achieving both cooling of the process cartridge 7 and prevention of toner contamination on the optical path will be described with reference to FIG. FIG. 4 is a cross-sectional view showing the air path configuration of the process cartridge 7.

  As shown in FIG. 4, in this embodiment, the ventilation fan 41 is arrange | positioned as a ventilation means so that it may connect with the substantially closed space 67 which is the space (airflow area) used as an air path. The blower fan 41 causes air to flow in the direction of the rotation axis of the photosensitive drum 1. Further, the air duct 42 is disposed so as to connect the air blowing fan 41 and the substantially closed space 67.

  The blower fan 41 is disposed on the wall surface of the apparatus main body. This is for blowing fresh air (cold wind). As a result, wind that is cooler than the duct opening 43 can be actively blown into the substantially closed space 67. As a result, heat can be exhausted by removing heat from the outer wall of the process cartridge 7 and the image carrier, and the toner, the photosensitive drum 1, the developing roller 24, and the cleaning unit 8 that do not want to rise in temperature can be efficiently cooled. Can do.

  Further, as described above, the substantially closed space 67 and the optical path area 68 are separated by the protruding portion 61 and the groove portion 62. For this reason, the wind generated by the blower fan 41 flows only in the substantially closed space 67 and does not flow in the optical path area 68. As described above, the wind does not flow into the optical path area 68 inside the exposure unit 3 and the process cartridge 7. It is possible to prevent dust and dirt from the outside of the apparatus from entering and adhering to the optical path.

  In addition, the optical path area 68 is in a substantially windless state. For this reason, it is possible to prevent optical path contamination due to toner scattering. As a result, image defects such as density reduction due to optical path contamination can be prevented.

[Process cartridge cooling method]
A method for cooling the process cartridge 7 of the color image forming apparatus of this embodiment will be described with reference to FIG. FIG. 5 is a perspective view showing a method for cooling the process cartridge 7.

  When the user attaches or removes the process cartridge 7, the opening / closing door 40 on the front side of the apparatus is opened as shown in FIG. When the opening / closing door 40 is opened, the process cartridge 7 is exposed. Therefore, the user can attach / detach the process cartridge 7 to / from the front side of the apparatus main body.

  A blower duct 42 is disposed in the opening / closing door 40, and is configured to be connected to an air inlet 44 provided on the left wall surface of the color laser printer 100 when the opening / closing door 40 is closed. Due to such a configuration, the cold wind sucked from the air inlet 44 is guided to the duct opening 43 and then blown into the substantially closed space 67.

  As described above, in the present embodiment, in order to achieve both the cooling of the process cartridge 7 and the problem of toner contamination of the scanner unit having the exposure unit 3, the air flow area that is the air path and the air flow that is the latent image optical path. Separates the area. Specifically, the protruding protrusion 61 (61a, 61b, 61c, 61d) and the concave groove 62 (62a, 62b, 62c, 62d) are arranged to mesh with each other. Thereby, an airflow area and an optical path area are partitioned off. Then, since the air blown from the blower fan 41 passes only through the air flow area, the process cartridge 7 can be effectively cooled.

  On the other hand, since the air blown from the blower fan 41 is difficult to reach the optical path area, the inside of the optical path area is a substantially windless space. In this way, it is possible to prevent optical path contamination due to toner scattering. Furthermore, by setting the outer wall of the process cartridge 7 as the inner surface of the air path, a compact air path can be formed without increasing the distance between the image carriers more than necessary.

  As a result, it is possible to achieve both a countermeasure against an image defect due to toner adhesion and a countermeasure for preventing a temperature rise in the image forming unit. As a result, even when printing is performed in an installation environment or continuous print mode while ensuring images over a long period of time without maintenance by the user, the temperature of the image carrier, transfer means, and image forming unit is increased. Image defects can be prevented.

  Further, as a member that separates the airflow area and the optical path area, the protrusion 61 and the groove 62 are formed integrally with the outer wall of the process cartridge. Thereby, it is possible to reliably partition the two spaces with a compact and inexpensive component configuration.

  The process cartridge is detachably supported from the apparatus main body, and the airflow area is provided with air blowing means so that air flows in the longitudinal direction of the image carrier from the side where the process cartridge is attached / detached. As a result, the heated air is smoothly discharged from the machine, and an air flow that does not circulate the heated air in the machine is simply formed. That is, on the side where the process cartridge is attached and detached, electrical parts such as a motor and mechanical parts such as gears are arranged on the side opposite to the air blowing means. Then, a motor, which is one of the heat sources, is arranged on the downstream side of the air flow, and the process cartridge can be exhausted without being exposed to the heated air.

  Further, the side on which the process cartridge is attached / detached is the front side of the image forming apparatus, and has an opening / closing door for attaching / detaching the process cartridge to the front side of the apparatus and an air blower on the inner surface of the opening / closing door. Accordingly, in recent years, an image forming apparatus having one of the typical configurations of a tandem type color image forming apparatus having a sheet conveying direction and a process cartridge attaching / detaching direction as shown in FIG. Such an ideal air flow can be formed.

  Further, in both image formation and non-image formation, the protruding portion and the groove are arranged so as to mesh with each other, thereby creating a partition state in both the image formation and non-image formation states. Can do. As a result, it is possible to achieve both a long life of the image carrier and the developing unit and cooling of the image forming unit.

[Other Embodiments]
In the above-described embodiment, the process cartridge 7 is cooled by the blower fan 41 from the front side of the image forming apparatus. However, the present invention is not limited to this. For example, the cooling unit may be a blower fan or an intake fan, and may be disposed behind the image forming apparatus. However, in the tandem type color image forming apparatus having the sheet conveyance direction and the attachment / detachment direction of the process cartridge 7 as shown in FIG. 2, a heat source is rarely arranged on the front side of the image forming apparatus. Further, since a heat source such as a power source or a motor is often disposed behind the image forming apparatus, it is effective to cool the image forming apparatus from the front side with a blower fan as in the present embodiment.

1 is a longitudinal sectional view showing an overall configuration of a color laser printer 100. FIG. FIG. 3 is a perspective view showing a configuration for attaching / detaching a process cartridge 7 and a feeding cassette 11. Sectional drawing which shows the attachment or detachment structure of the process cartridge 7, or an air path structure. FIG. 6 is a cross-sectional view showing the air path configuration of the process cartridge 7. FIG. 6 is a perspective view showing a method for cooling the process cartridge 7. 2 is an explanatory diagram of a configuration of a color image forming apparatus. FIG.

  DESCRIPTION OF SYMBOLS N ... Fixing nip part, S ... Sheet, 1 ... Photoconductor drum, 2 ... Charging means, 3 ... Exposure means, 4 ... Developing unit, 5 ... Cleaner unit, 7 ... Process cartridge, 8 ... Drum cleaning blade, 9 ... Feeding Feed roller, 10 ... Feeding device, 10A ... Conveying roller pair, 11 ... Feed cassette, 12 ... Primary transfer roller, 13 ... Intermediate transfer unit, 13A ... Intermediate transfer belt, 13B ... Drive roller, 13C ... Tension roller, 14 DESCRIPTION OF SYMBOLS Fixing part, 14A ... Fixing belt, 14B ... Elastic pressure roller, 14C ... Belt guide member, 15 ... Secondary transfer part, 16 ... Secondary transfer roller, 17 ... Registration roller pair, 18 ... Transfer belt cleaning device, 20 ... Discharge roller pair, 21 ... insertion guide, 22 ... insertion rib, 23 ... separation pad, 24 ... developing roller, 25 ... developer application roller, 30 ... Mouth hole 32 ... partition plate 40 ... opening / closing door 41 ... blower fan 42 ... blower duct 43 ... duct opening 44 ... intake port 61 ... convex shape 62 ... concave shape 63 ... upper surface 64 ... Inner surface, 65 ... lower surface, 66 ... inner surface, 67 ... substantially closed space, 68 ... optical path area, 100 ... color laser printer

Claims (4)

A plurality of image carrier units integrally configured with an image carrier and process means acting on the image carrier; and a transfer belt unit having an endless belt disposed so as to be in contact with the plurality of image carriers; An image forming apparatus having air blowing means for sending air into the apparatus,
A protrusion and a groove are formed on the outer wall of the image carrier unit so as to mesh with each other.
The blowing unit is formed in a space between one of the plurality of image carrier units, the groove of the image carrier unit adjacent to the projection, and the transfer belt unit. An image forming apparatus, wherein air is sent to an air path. The image carrier unit is detachably supported from the apparatus main body,
2. The image forming apparatus according to claim 1, wherein the blowing unit sends air in the longitudinal direction of the image carrier from the side where the image carrier unit is attached and detached with respect to the air path. The side on which the image carrier unit is attached and detached is the front side of the image forming apparatus,
An opening / closing door for attaching / detaching the image carrier unit is disposed on the front side of the apparatus,
The image forming apparatus according to claim 1, wherein the air blowing unit is disposed on an inner surface of the opening / closing door. The developing means has a developing roller for attaching a developer to the image carrier,
The state of the developing means includes a first state in which the developing roller and the image carrier are in contact with each other, and a second state in which the developing roller and the image carrier are separated from each other.
4. The projecting portion and the groove portion are formed so that air from the blowing means is blown only to the air passage in the first state and the second state. The image forming apparatus according to any one of the above.

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