JP4558426B2 - 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 cooling fan and a duct around an image forming mechanism of an image forming apparatus. As described above, conventionally, the writing unit and the image forming unit are cooled by providing a dedicated cooling fan and duct for each unit.
Japanese Patent Application Laid-Open No. 2003-228561 discloses a technique for partitioning a writing unit and a photosensitive unit by a partition plate to form an air flow channel for cooling.
JP 2002-318522 A JP 10-115958 A Japanese Patent No. 3363398

  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, a member such as a duct and a partition plate is required, which is not suitable for downsizing the machine.

In view of the above-described problems, the present invention provides a tandem type 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.

According to the first aspect of the present invention, a light beam from the light source unit is polarized and scanned by an optical polarizer, and the light beam is transmitted to a plurality of image carriers through an optical system disposed around the optical polarizer. A writing unit having a configuration for guiding and forming an image on a surface to be scanned, a photosensitive unit having an image forming member having at least the image carrier, and a developing unit for forming a toner image on the image carrier A plurality of image forming units, and a cooling fan that blows cooling air into a space formed between the writing unit and the plurality of image forming units. The image 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 a space formed between the writing unit and the plurality of image forming units is cooled. Cold blown from fan And the air flow passage of the wind, the height h of the cooling fan shown by the distance between both ends in the direction perpendicular to the flow direction airflow from the cooling fan of the cooling fan, and the writing unit and said plurality of image forming units Between the height H of the air flow channel indicated by the distance between the photosensitive unit and the developing unit adjacent to the cooling fan when a relationship of h> H is established, A space formed between a first inclination provided on the cooling fan arrangement side and a second inclination provided on the cooling fan arrangement side, above the writing unit adjacent to the cooling fan. width Hf of airflow inlet is, the cooling fan of the much larger than the height h, the cooling fan are perpendicular width direction of the direction and the airflow inlet flowing airflow from the cooling fan within the width of the airflow inlet image forming disposed It characterized in that it was the location.

  A second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the image forming unit is detachable.

  The invention according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein at least one of the photosensitive unit and the developing unit is separable from the image forming unit. To do.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, a first slope provided on the cooling fan arrangement side below the photosensitive unit or the developing unit adjacent to the cooling fan. And the inclination of the second inclination provided on the cooling fan arrangement side at the upper part of the writing unit adjacent to the cooling fan are substantially equal, and the first inclination and the second inclination The air flow path, which is a space formed between the two, is substantially equally divided into two by the central axis A of the cooling fan.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the image forming unit is detachable.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, at least one of the photosensitive unit and the developing unit is separable from the image forming unit. To do.

According to a seventh aspect of the present invention, in the image forming apparatus according to the first or fourth aspect, in the plurality of image forming units including the developing unit and the photoreceptor unit, the gap between the image forming units is narrowed. An airflow guide provided in parallel with the airflow channel is provided in the developing unit or the photoconductor unit.

The invention according to claim 8 is the image forming apparatus according to claim 7, wherein the image forming unit is detachable.

According to a ninth aspect of the present invention, in the image forming apparatus according to the seventh or eighth aspect, at least one of the photosensitive unit and the developing unit is separable from the image forming unit. To do.

  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.

In the best mode for carrying out the present invention, a light beam from a light source unit is polarized and scanned by an optical polarizer, and the light beam is converted 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 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. The 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 a space formed between the writing unit and the plurality of image forming units is formed. Blown from the cooling fan A cooling air flow path, the cooling fan height h indicated by the distance between both ends of the cooling fan, and the air flow indicated by the distance between the writing unit and the plurality of image forming units. When a relationship of h> H is established between the height H of the flow path and the height H of the flow path, a lower portion of the photosensitive unit adjacent to the cooling fan or the developing unit and provided on the cooling fan arrangement side. The width H _{f of the} airflow inlet, which is a space formed between the inclination of 1 and the second inclination provided on the cooling fan arrangement side above the writing unit adjacent to the cooling fan, The image forming apparatus is configured to be larger than the height h of the cooling fan.

(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 sectional view of an image forming apparatus 1 according to the present embodiment. FIG. 2 is a diagram showing an image forming member formed into a cartridge of the image forming apparatus 1 of the present embodiment. Of the toner image forming portions Y, M, C, and K shown in FIG. 3 is an enlarged cross-sectional view showing a schematic configuration of a part Y. FIG. 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 be separated from the image forming apparatus 1 or may be integrated. Further, the image forming unit 2 as a single unit of the photosensitive unit 2A, the single unit of the developing unit 2B, or the entire unit may be integrated with the image forming apparatus 1 even if it is detachable. May be.

  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 toner image of a predetermined color 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.

  Note that the image forming apparatus 1 of the present embodiment is a tandem type color laser printer, but the present invention can also be applied to a monochrome laser printer including a set of toner image forming units using black toner. The present invention can also be applied to other image forming apparatuses such as copying machines, printers, and facsimile machines.

Next, the image forming apparatus 1 of the present embodiment to which the present invention is applied will be specifically described below. FIG. 3 is an enlarged cross-sectional view of the periphery of the cooling fan 7, the image forming unit 2, and the writing unit 21 in the image forming apparatus 1 of the present embodiment. As shown in FIG. 3, the image forming apparatus 1 according to the present embodiment has a configuration in which the cooling fan 7 is disposed on the left side of the apparatus. The cover 20 is also included.) A slope 26 is provided at the lower left portion of the developing unit 2B. Therefore, the width H _f of the airflow passage entrance formed by the developing unit 2B and the writing unit 21 shown on the left side of FIG. 3 is larger than the height h of the cooling fan 7 (H _f > h).

  Here, for comparison with the image forming apparatus 1 of the present embodiment, a conventional example will be described below with reference to FIGS. 4, 5, and 6. FIG. 5 is an enlarged cross-sectional view showing the periphery of the image forming unit 2, the writing unit 21, and the cooling fan 23. As shown in FIG. 5, a relationship is established in which the height h1 of the cooling fan 23 is greater than the distance H1 between the bottom side of the image forming unit 2 and the top of the writing unit 21 (h1>). H1). In this case, in the portions P1 and P2 surrounded by the dotted line shown in FIG. 5, the cooling air from the cooling fan 23 is blocked and windage loss occurs, so that the cooling air cannot be efficiently blown downstream. .

  In order to eliminate this windage loss, a cooling fan 24 as shown in FIG. 6 may be used. The height h2 of the cooling fan 24, the height h1 of the cooling fan 23 shown in FIG. 5, and the distance H1 between the image forming unit 2 and the writing unit 21 are in a relationship of h2 <H1 <h1. Is established. In general, the numerical value of H1 is determined by the layout of the machine, the size of the optical element in the writing unit 21, and the performance (optical path length), but is often 50 mm or less. The cooling fan shown in FIG. The height h2 of 24 is often less than 50 mm. In this case, since it becomes a special cooling fan smaller than the size of the generally circulated cooling fan, there is a problem that the cost is increased.

  FIG. 4 is an enlarged cross-sectional view of the periphery of the image forming unit 2, the writing unit 21, and the cooling fan 23. In FIG. 4, a duct 22 that guides the airflow of the cooling air from the cooling fan 23 is provided in order to eliminate the windage loss that occurs in the portions P <b> 1 and P <b> 2 as shown in FIG. 5. In this case, the cost is increased by the provision of the duct 22, and further, since the duct 22 is provided, the distance l1 between the cooling fan 23 and the left end portions of the image forming unit 2 and the writing unit 21 is provided. Since it becomes larger than l shown in FIG. 3 in the case of no, there is a problem that the machine size is increased accordingly.

  To solve the problem described above, as shown in FIG. 3, in the image forming apparatus 1 of the present embodiment, an inclination 25 is formed on the upper left end of the writing unit 21, and an inclination 26 is applied on the lower left end of the developing unit 2B. Are provided, and the slope 25 and the slope 26 function as an air flow guide for the cooling air from the cooling fan 7, whereby the cooling air can be efficiently sent to the downstream side. Further, since the image forming apparatus 1 of the present embodiment shown in FIG. 3 does not need to be provided with the duct 22 as shown in FIG. 4, the cooling fan 7 and the left end portions of the writing unit 21 and the developing unit 2B are provided. The distance l can be made smaller than the distance l1 shown in FIG. Therefore, there is no need to increase the machine size for installing the duct 22. Further, since it is not necessary to use a specially sized cooling fan 24 as shown in FIG. 6 in order to prevent the occurrence of windage loss, a general low-cost cooling fan can be used.

  Next, the airflow guide unit provided in the image forming apparatus 1 of the present embodiment will be described with reference to FIG. As shown in FIG. 7, an inclination 25 is provided at the lower left portion of the image forming unit 2, and an inclination 26 is provided at the upper left portion of the writing unit 21, and these inclination 25 and inclination 26 are cooled by the cooling fan 7. It functions as an airflow guide that guides the airflow caused by the wind. These air flow guide portions are so divided that the space Q formed by the air flow guide portion is substantially divided into two by the central axis A of the cooling fan 7 shown by a one-dot chain line in FIG. Provided.

  Therefore, as shown in FIG. 7, at the front part of the airflow inlet of the cooling air from the cooling fan 7, the distance between the imaging unit 2 and the central axis A is R1, and the distance between the writing unit 21 and the central axis A is Assuming R2, R1 and R2 have the same relationship. At the rear of the airflow inlet, if the distance between the image forming unit 2 and the central axis A is S1, and the distance between the writing unit 21 and the central axis A is S2, S1 and S2 are in the same relationship. By adopting the apparatus configuration as described above, the same amount of cooling air is blown from the cooling fan 7 to both the image forming unit 2 and the writing unit 21, so that both units can be efficiently cooled together. Can do.

  Note that the slope 25 of the lower left portion of the image forming unit 2 and the slope 26 of the upper left portion of the writing unit 21 shown in FIG. For example, as shown in FIG. 8, when the inclination of the lower left slope 27 of the image forming unit 2 is larger than the inclination of the upper left slope 28 of the writing unit 21, the cooling air from the cooling fan 7 (arrow B1) ) First hits the inclination 27 of the image forming unit 2 and is sprayed downward (arrow B1 → B2 → B3). After that, it strikes the inclination 28 of the writing unit 21 and is sprayed upward (arrow B4). Thereafter, in the space (airflow channel) formed between the image forming unit 2 and the writing unit 21, the cooling air flows on the image forming unit 2 side as indicated by arrows B5 and B6. Therefore, more cooling air flows to the image forming unit 2 side than to the writing unit 21 side, and both the writing unit 21 and the image forming unit 2 cannot be cooled uniformly. .

Next, the photoreceptor unit 2A of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. L _Y shown in FIG. 9 is yellow image forming light, and the image forming unit 2 including the developing unit 2B and the photosensitive unit 2A on the left side of FIG. 9 is a yellow toner image forming unit. Further, L _M shown in FIG. 9 is a imaging light magenta, the image forming units 2 composed of 9 right of the developing unit 2B and a photoreceptor unit 2A is a toner image forming portion of the magenta color.
Between the image forming unit 2 that is the yellow toner image forming unit on the left side of FIG. 9 and the image forming unit 2 that is the magenta toner image forming unit on the right side of FIG. 9, that is, the photosensitive unit 2A for yellow, A gap is provided between the unit with the magenta developing unit 2B because there are assembled parts and the like. Since the cooling air from the cooling fan 7 escapes to the gap, the cooling air hardly reaches the downstream side opposite to the cooling fan arrangement side.

Therefore, a part of the photoconductor unit 2A shown in FIG. 9 has a shape 29 indicated by oblique lines, so that the gap t between the image forming units 2 is set to a narrower gap t ′.
By providing the photosensitive member unit 2A with the shape 29 as described above, the gap t between the adjacent image forming units 2 and the developing unit 2B is set to a narrower gap t ′, and the amount of cooling air passing through the gap can be reduced. Therefore, it is possible to prevent the amount of cooling air from being extremely reduced on the downstream side opposite to the cooling fan 7 arrangement side.

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 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. 10 is a partial cross-sectional view showing an image forming unit, a writing unit, and a cooling fan in a conventional image forming apparatus. FIG. 10 is a partial cross-sectional view showing an image forming unit, a writing unit, and a cooling fan in a conventional image forming apparatus. It is a diagram showing an example of a cooling fan in a conventional image forming apparatus. FIG. 2 is a partial 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. 8 is a partial cross-sectional view showing an image forming unit, a writing unit, and a cooling fan as a comparative example of the image forming apparatus of the present embodiment shown in FIG. 7. FIG. 3 is a partial cross-sectional view illustrating a developing unit, a photosensitive unit, and a cooling fan in the image forming apparatus of the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming unit 2A Developing unit 2B Photosensitive unit 3 Photosensitive unit 4 Intermediate transfer belt 5 Writing unit 6 Toner container 7 Cooling fan 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 23 Cooling fan 24 Cooling fan 25 Inclined 26 Inclined 27 Inclined 28 Inclined 29 Part A Central axis B1 Cooling air B2 Cooling air B3 Cooling air B4 Cooling air B5 Cooling air B6 Cooling air C Cyan toner image forming portion h Cooling fan height h1 Cooling fan height h2 Cooling fan height H Width l imaging of the airflow passage inlet formed between the distance H _f developing unit to bottom writing unit upper part of the distance H1 imaging unit to bottom writing unit upper part of the image unit to bottom writing unit upper Distance between the left end of the unit and the writing unit and the cooling fan 11 Distance between the left end of the image forming unit and the writing unit and the cooling fan L Light beam L _Y yellow image light L _M magenta image light K Black Toner image forming portion M Magenta toner image forming portion P1 Wind loss generating portion P2 Wind loss generating portion Q Space formed between the inclination 25 and the inclination 26 R1 Distance between the image forming unit and the central axis A R2 Writing Distance between unit and center axis A S1 Distance between image forming unit and center axis A S2 Distance between writing unit and center axis A t Distance between image forming units t 'Distance between image forming units Y Low toner image forming section

Claims (9)

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;
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 is formed between the writing unit and the plurality of image forming units. The space is defined as an air flow path of cooling air blown from the cooling fan, and the cooling fan height h indicated by the distance between both ends in a direction orthogonal to the direction of air flow from the cooling fan of the cooling fan , A photosensitive unit adjacent to the cooling fan when a relationship of h> H is established between the height H of the air flow channel indicated by the distance between the embedded unit and the plurality of image forming units. Alternatively, a first slope provided on the cooling fan arrangement side, which is the lower part of the developing unit, and a second inclination provided on the cooling fan arrangement side, which is an upper part of the writing unit adjacent to the cooling fan. With a slope of The width H _f of the airflow inlet is a space that is formed, the cooling fan of the much larger than the height h, and the width direction of the direction and the airflow inlet flow stream from the cooling fan are perpendicular, the cooling fan airflow An image forming apparatus arranged within a width of an entrance .   The image forming apparatus according to claim 1, wherein the image forming unit is detachable.   The image forming apparatus according to claim 1, wherein at least one of the photosensitive unit and the developing unit is separable from the image forming unit. A lower portion of the photoconductor unit or the developing unit adjacent to the cooling fan, a first inclination provided on the cooling fan arrangement side, and an upper portion of the writing unit adjacent to the cooling fan, The inclination of the second inclination provided on the cooling fan arrangement side is substantially equal, and the air flow path which is a space formed between the first inclination and the second inclination is the cooling fan. The image forming apparatus according to claim 1, wherein the image forming apparatus is divided into two substantially evenly by the central axis A. The image forming apparatus according to claim 4, wherein the image forming unit is detachable. The image forming apparatus according to claim 4, wherein at least one of the photosensitive unit and the developing unit is separable from the image forming unit. In the plurality of image forming units including the developing unit and the photoconductor unit, an airflow guide portion provided in parallel with the airflow channel is provided so as to narrow a gap between the image forming units. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided in a unit. The image forming apparatus according to claim 7, wherein the image forming unit is detachable. 9. The image forming apparatus according to claim 7, wherein at least one of the photosensitive unit and the developing unit is separable from the image forming unit.

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