JP4565942B2 - Image forming apparatus - Google Patents

Description

In the present invention, a latent image formed on an image carrier is developed with a developer by an optical writing device that writes a latent image by irradiating a light beam onto a scanned surface of a plurality of image carriers, and then sequentially transferred. transferred to wood, copier for forming a monochrome image or a multi-color image fixed by the fixing means relates a printer, a facsimile, an image forming equipment such as a plotter.

Patent Document 1 discloses a technique of providing a dedicated cooling fan and duct for cooling a writing unit provided in an image forming apparatus such as a copying machine or a printer. Patent Document 2 discloses a technique of providing a dedicated fan and duct for cooling around an image forming mechanism of an image forming apparatus. Thus, conventionally, the cooling of the writing unit and the image forming unit is performed by providing a dedicated fan and duct for each unit.
Patent Document 3 discloses a technique in which a cooling fan is disposed in the vicinity of the writing unit and the developing unit to simultaneously cool both the writing unit and the developing unit. However, the technique disclosed in Patent Document 3 is not applied to a tandem machine having only one image forming system in the configuration of the image forming apparatus.
JP 2002-318522 A JP 10-115958 A JP-A-7-191593

  However, in the apparatus configuration as shown in the prior art, there is a problem that the cost becomes high because individual cooling fans and ducts are required for the individual units of the writing unit and the image forming unit. In addition, there is no consideration when a plurality of image forming units are installed, and only a cooling fan is arranged in the vicinity of the writing unit and the image forming unit. The cooling fan is provided with a guide duct. Therefore, there are problems such as high cost and large machine size.

  Further, in the image forming apparatus having a configuration in which an air flow channel for cooling each unit is formed in a space formed between the image forming unit and the writing unit, the above-described dedicated duct, partition plate, and the like are provided. If it is not provided, the cooling air from the cooling fan does not flow efficiently, and there is a problem that the cooling effect is small. Further, in order to increase the cooling effect, there is a problem that the number of cooling fans to be used needs to be increased.

In view of the above-described problems, the present invention provides a tandem machine for an image forming apparatus in which cooling air is sent by a single cooling fan without providing a dedicated duct or partition plate, and a plurality of image forming units and a single image forming unit. and to provide an image forming equipment which made it possible to cool the writing unit efficiently.

In order to achieve the above-mentioned object, the present invention is configured to scan a light beam from a light source unit with an optical polarizer, and to convert the light beam into a plurality of images via an optical system arranged around the optical polarizer. A writing unit having a configuration for guiding and imaging on a surface to be scanned of the carrier, a photosensitive unit having an image forming member having at least the image carrier, and a toner image on the image carrier An image comprising: a plurality of image forming units each including a developing unit to be formed; and a cooling fan that blows cooling air to a space formed between the writing unit and the plurality of image forming units. In the forming apparatus, the plurality of image forming units are arranged in a line on a straight line, the writing unit is arranged in parallel with the plurality of image forming units, and the plurality of image forming units and the writing unit Interval 2 between 1 distance, is the cooling fan is positioned so that the center axis of the cooling fan is located, the distance between the plurality of image forming units the write unit between fan ends of the cooling fan has The image forming apparatus is characterized by being equal to or larger than the size of the image forming apparatus .

  According to the present invention, in the tandem machine of the image forming apparatus, the cooling air is sent by one cooling fan without providing a dedicated duct or a partition plate, so that a plurality of image forming units and one writing unit can be efficiently used. Can be cooled.

  The best mode for carrying out the present invention is that in an image forming apparatus, a light beam from a light source unit is polarized and scanned by an optical polarizer, and the light is transmitted through an optical system disposed around the optical polarizer. A writing unit having a configuration for guiding a beam onto a scanned surface of a plurality of image carriers, and an image forming member having at least the image carrier, and the image carrier A plurality of image forming units each including a developing unit that forms a toner image on a body; and a cooling fan that blows cooling air to a space formed between the writing unit and the plurality of image forming units. The plurality of image forming units are arranged in a line on a straight line, the writing unit is arranged in parallel with the plurality of image forming units, and between the plurality of image forming units and the writing unit About half of the interval The release, the central axis of the cooling fan is arranged the cooling fan so as to be located.

(Embodiment)
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

  First, the configuration, operation, and action of an image forming apparatus according to the present embodiment to which the present invention is applied will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment. FIG. 2 is a diagram showing an image forming member formed into a cartridge of the image forming apparatus according to the present embodiment. Of the toner image forming portions Y, M, C, and K shown in FIG. It is an enlarged view which shows schematic structure of Y. The other toner image forming units M, C, and K shown in FIG. 1 have the same configuration as that of the yellow toner image forming unit Y shown in FIG.

  The image forming unit 2 that is the yellow toner image forming portion Y shown in FIG. 2 includes a photoreceptor unit 2A and a developing unit 2B. The photoreceptor unit 2A and the developing unit 2B may have an integral structure. The surface of the photoreceptor 3 that rotates in the clockwise direction shown in FIG. 2 is charged to a predetermined potential by the charging roller 9. In order to prevent the surface of the charging roller 9 from being soiled, a cleaning roller 10 is provided. The cleaning roller 10 cleans the surface of the charging roller 9 from soiling. The uniformly charged photoconductor 3 is exposed by the light beam L indicated by the arrow from the writing unit 5, and a latent image is formed on the photoconductor 3.

  As shown in FIG. 2, the developing unit 2 </ b> B includes a developing roller 16 disposed so as to be partially exposed from the opening of the developing case 11, conveying screws 12 and 14, a developing doctor 15, and a toner density sensor 13. It has. The toner can be supplied from the toner container 6 shown in FIG. A developing case 11 shown in FIG. 2 contains a two-component developer (hereinafter simply referred to as a developer) containing a magnetic carrier and a negatively charged toner. The developer is frictionally charged while being agitated and conveyed by the conveying screws 12 and 14 shown in FIG. 2 and then carried on the surface of the developing roller 16. Then, after the layer thickness is regulated by the developing doctor 15, the developer is conveyed to a developing position facing the photosensitive drum 3, where toner adheres to the electrostatic latent image on the photosensitive drum 3. Due to the adhesion of the toner, a predetermined color toner image is formed on the photosensitive drum 3. As a result of such development, the developer that has consumed toner is returned to the developing case 11 as the developing roller 16 rotates. Further, the toner concentration of the developer in the developing case 11 is detected by the toner concentration sensor 13 and the toner is replenished from the toner storage container 6 to the space above the conveying screw 12 as necessary.

  By the way, as a reference when the image forming unit 2 shown in FIG. 2 is attached to and detached from the image forming apparatus 1 shown in FIG. In addition, positioning reference portions are provided on the frames of the photosensitive unit 2A on the front side and the back side of the photosensitive member 3, respectively, and when the photosensitive unit 2A is mounted on the image forming apparatus 1, the reference portion and the image are provided. By the engaging portion provided in the forming apparatus 1, the photoreceptor unit 2A can be reliably positioned at a predetermined mounting position.

  As shown in FIG. 1, the photosensitive member 3 contacts an intermediate transfer belt 4 provided in a transfer unit disposed above the photosensitive member 3 to form a transfer nip as a transfer position. The toner developed on the photosensitive member 3 is transferred onto the intermediate transfer belt 4, and the toner remaining on the photosensitive member 3 without being transferred is removed by a cleaning blade 17 shown in FIG. It is conveyed to a storage unit (not shown). Further, the cooling fan 7 shown in FIG. 1 is a cooling fan for cooling the writing unit 5 and the image forming unit 2 and sucks air from outside the machine and sends cooling air to the inside. The duct 8 shown in FIG. 1 is also a duct that also serves to support the cooling fan 7. By this duct 8, the writing unit 5 and the image forming units 2 of Y, M, C, and K shown in FIG. Cooling air is sent during

  Next, the image forming apparatus of the present embodiment to which the present invention is applied will be specifically described below. FIG. 3 is a partial cross-sectional view of the image forming apparatus of the present embodiment. The cooling fan 7 shown in FIG. 3 is an axial fan. The axis A of the cooling fan 7 is indicated by a one-dot chain line in FIG. 3, and the cooling fan 7 has cooling air in the space between the upper cover 20 of the writing unit 21 and each image forming unit 2 shown in FIG. Is sending. Further, a light beam L as image forming light is emitted from the writing unit 21 shown in FIG.

  A distance H shown in FIG. 3 is a distance between the upper portion of the upper cover 20 of the writing unit 21 and the bottom sides of the photosensitive unit 2A and the developing unit 2B. Further, the image forming unit 2 located at the upper left in FIG. 3 is a yellow image forming system, and the image forming unit 2 located at the upper right is a magenta image forming system. As described with reference to FIG. 1, the image forming apparatus according to the present embodiment includes toner image forming portions Y, M, C, and K of four colors of yellow, magenta, cyan, and black. Are arranged at equal intervals.

  In the image forming apparatus of the present embodiment, as shown in FIG. 3, the distance H is approximately ½H of the above-described distance H in the space formed between the upper cover 20 of the writing unit 21 and each image forming unit 2. The central axis A of the cooling fan 7 is located at the position. Therefore, the cooling air from the cooling fan 7 strikes the writing unit 21 and each image forming unit 2 almost evenly. As a result, the writing unit 21 and each image forming unit 2 can be efficiently cooled at the same time without a dedicated duct or partition plate.

  By the way, when the height h of the cooling fan 7 is larger than the distance H, the cooling fan 7 is cooled by the upper part of the upper cover 20 of the writing unit 21 and the lower part of the image forming unit 2 (photosensitive unit 2A and developing unit 2B). Since the wind is blocked, the cooling efficiency is lowered. Conventionally, as shown in FIG. 5, the height h of the cooling fan 7 is such that the upper part of the upper cover 20 of the writing unit 21 and the bottom side of the image forming unit 2 composed of the photosensitive unit 2A and the developing unit 2B. When the distance H is larger than the distance H, the duct 22 for guiding the cooling air is required. Therefore, in this case, the distance l from the left end of the writing unit 21 and the image forming unit 2 to the cooling fan 7 is necessarily increased because the duct 22 is provided, and the machine size is increased. Moreover, in the part P enclosed with the dotted line shown in FIG. 5, a windage loss generate | occur | produces the malfunction that cooling efficiency worsens.

  On the other hand, in the image forming apparatus of the present embodiment, as shown in FIG. 3, the height h of the cooling fan 7, the upper part of the upper cover 20 of the writing unit 21, the photosensitive unit 2A and the developing unit 2B. The distance H from the bottom side of the image forming unit 2 is substantially the same. Therefore, the distance l shown in FIG. 5 can be reduced by the amount that the duct 22 is not provided, and the machine can be downsized. Further, since the height h of the cooling fan is substantially equal to or smaller than the distance H, there is no need to provide the duct 22 shown in FIG. 5, so there is no cost increase and the cooling efficiency of the cooling fan 7 does not drop.

  Next, as shown in FIG. 4, when the horizontal size of the developing unit 2B is S1 and the horizontal size of the photosensitive unit 2A is S2, the sum S of S1 and S2 is the same as the developing unit 2B and the photosensitive unit 2A. The total horizontal size. As described above, the image forming apparatus according to the present embodiment performs writing for four colors of yellow, magenta, cyan, and black with one writing unit. 4K≈K and a relationship in which the left end portions of the image forming unit 2 and the writing unit 5 on the arrangement side of the cooling fan 7 coincide with each other as shown in FIG.

  However, the reason that 4S = K is set instead of 4S = K is that the gap y shown in FIG. 4 is used in order to avoid interference due to assembly and stacking of parts between adjacent image forming units 2 of other colors. This is because it is necessary. In general, it is sufficient that the gap y is 1 mm to 2 mm. Therefore, the meaning of ≒ is K-3y ≒ K. Since the relationship 4S≈K≈K−3y is established, a consistent air flow path can be formed by the cooling fan 7 shown in FIG. 4, and the image forming units 2 for all four colors in the image forming apparatus of the present embodiment. Can be efficiently cooled. If the above relationship does not hold, there is a problem that a wasteful space is created on the airflow passage, the machine size is increased, and the cooling effect is reduced.

1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment. FIG. 2 is a configuration cross-sectional view of an image forming unit in the image forming apparatus of the present embodiment. FIG. 2 is a partial enlarged cross-sectional view illustrating an image forming unit, a writing unit, and a cooling fan in the image forming apparatus of the present embodiment. FIG. 3 is a partial enlarged cross-sectional view for explaining a relationship between an image forming unit, a writing unit, and a cooling fan in the image forming apparatus of the present embodiment. It is a partial expanded sectional view for demonstrating the cooling fan and duct in the conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming unit 2A Developing unit 2B Photoconductor unit 3 Photoconductor 4 Intermediate transfer belt 5 Writing unit 6 Toner storage container 7 Cooling fan 8 Duct 9 Charging roller 10 Cleaning roller 11 Developing case 12 Conveying screw 13 Toner density Sensor 14 Conveying screw 15 Developing doctor 16 Developing roller 17 Cleaning blade 18 Toner conveying auger 19 Dust-proof glass 20 Upper cover of writing unit 21 Writing unit 22 Duct A Center axis C Cyan toner image forming portion h Cooling fan height H The distance between the upper part of the upper cover and the bottom of the image forming unit l The distance between the left end of the image forming unit and the writing unit and the cooling fan L Light beam K Black toner image forming portion M Magenta toner image Forming part P Wind loss generating part Sum of horizontal size of development unit and horizontal size of photoconductor unit S1 Horizontal size of development unit S2 Horizontal size of photoconductor unit y Clearance for avoiding interference due to assembly and stacking of parts Y Yellow toner Image forming unit

Claims (2)

The light beam from the light source unit is polarized and scanned by an optical polarizer, and the light beam is focused on the scanning surfaces of a plurality of image carriers through an optical system arranged around the optical polarizer. A writing unit having a configuration for
A plurality of image forming units comprising a photoconductor unit including an image forming member having at least the image carrier and a developing unit for forming a toner image on the image carrier;
An image forming apparatus comprising: a cooling fan that blows cooling air to a space formed between the writing unit and the plurality of image forming units;
The plurality of image forming units are arranged in a line on a straight line, the writing unit is arranged in parallel with the plurality of image forming units,
The cooling fan is disposed such that a central axis of the cooling fan is located at a distance of approximately one half of a distance between the plurality of image forming units and the writing unit ;
The image forming apparatus , wherein a distance between the plurality of image forming units and the writing unit is equal to or greater than a size between both ends of the cooling fan . When performing N-color optical writing by the writing unit,
A total size S of the horizontal size S1 of the photosensitive unit and the horizontal size S2 of the developing unit for performing optical writing of a predetermined color which is a horizontal size in a direction in which the plurality of image forming units are arranged ; ,
Between the writing unit K,
The relational expression NS≈K holds,
Wherein the end position of the imaging unit of the cooling fan arrangement side, the image forming apparatus according to claim 1, characterized in that is matched with the end position of the writing unit.

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