JP2005043426A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which efficiently cools a photoreceptor with a simple structure and ensure high reliability. <P>SOLUTION: The image forming apparatus is characterised in that cooling fins 10 are disposed within the photoreceptor 2 and partitions are disposed for defining passages which guide air from a drying mechanism 27 towards the inside and outside of the photoreceptor 2 thereby the photoreceptor 2 is efficiently cooled, and a deterioration in the characteristics of the photoreceptor 2 is prevented and the output of high image quality prints is realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus including a photosensitive member that is supported rotatably and has a hollow structure.
[0002]
[Prior art]
An image forming apparatus that obtains an image by forming an electrostatic latent image on the surface of the photoconductive drum has an electrostatic characteristic in which the photoconductive drum is warmed by heat generated from a drive unit or a transfer body inside the machine during image formation. There was a problem that the image quality deteriorated due to deterioration.
[0003]
With respect to the above problem, the image forming apparatus described in Patent Document 1 described below measures the temperature of the photosensitive drum, cools the developer so as not to exceed a certain temperature, and increases the temperature of the photosensitive drum. It is intended to prevent characteristic deterioration and deterioration of the developer itself.
[0004]
However, in such an image forming apparatus, a cooling fan or a Peltier element is used as a cooling unit for the developer storage unit, and the cooling unit cannot efficiently cool the photosensitive drum. In order to cool the photosensitive drum with the cooling fan, it is essential to increase the size of the fan drive unit, which is not desirable from the viewpoint of power consumption, noise, and the like.
[0005]
In the apparatus described in Patent Document 2 shown below, air is introduced into the photoreceptor using a fan, and the solvent vapor is collected by activated carbon packed in the photoreceptor drum.
[0006]
However, the main purpose of this apparatus is to recover the solvent vapor using the space inside the photosensitive drum, and the photosensitive drum cannot be cooled directly and efficiently.
[0007]
Documents disclosing conventional image forming apparatuses include the following.
[0008]
[Patent Document 1]
JP 2001-282081 A [Patent Document 2]
Japanese Patent Laid-Open No. 2002-91251
[Problems to be solved by the invention]
As described above, in the conventional image forming apparatus, in order to cool the photosensitive drum, a cooling unit such as a cooling fan is individually installed, or the drive unit has to be enlarged. As a result, there is a problem in the long-term stability of the cooling means, and a control device for controlling the drive has to be added, resulting in problems in reliability and cost.
[0010]
In view of the above circumstances, an object of the present invention is to provide an image forming apparatus capable of efficiently cooling a photoreceptor and ensuring high reliability with a simple configuration.
[0011]
[Means for Solving the Problems]
The image forming apparatus of the present invention includes:
A photoconductor that is rotatably supported and has a hollow structure;
A charger for charging the photoreceptor;
An exposure device for writing an electrostatic latent image on the charged photoreceptor;
A developing unit that performs development using a liquid developer on the surface of the photoreceptor on which the electrostatic latent image is written;
A drying mechanism that outputs air to dry the liquid component remaining on the photoreceptor after development;
A transfer device for transferring the dried toner image on the photoreceptor to an image carrier;
An inner introduction partition arranged outside the drying mechanism and the photoreceptor to introduce the air output from the drying mechanism into the photoreceptor;
The photoreceptor is
At both ends along the rotation axis, there are air introduction holes for taking in the air output from the drying mechanism through the inner introduction partition wall, and cooling fins are provided inside.
[0012]
Air introduced into the photoconductor through the air introduction hole provided at one end at both ends of the photoconductor passes through the air introduction hole provided at the other end of the photoconductor. Further, an outer introduction partition wall arranged outside the photoconductor may be further provided so that the air is led out to the outside of the photoconductor and passes near the outer surface of the photoconductor.
[0013]
The cooling fin may have a flat plate whose longitudinal direction is parallel to the rotation axis direction inside the photoconductor, and an air passage hole may be opened in the flat plate.
[0014]
In the air passage hole, at least a portion of the end surface parallel to the rotation axis direction may be inclined with respect to the thickness direction of the flat plate.
[0015]
The photoreceptor has flange portions provided at both ends along the rotation axis,
The flange portion may include an introduction portion having a fan shape for introducing air output from the drying mechanism.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
(1) First Embodiment FIG. 1 shows a configuration of an image forming apparatus 1 according to a first embodiment of the present invention. This apparatus is a wet image forming apparatus using liquid toner.
[0018]
The image forming apparatus 1 is disposed around a housing 6 that covers the entire apparatus, a photoreceptor 2, a charger 3 that performs charging, and a periphery of the photoreceptor 2, and irradiates an exposure beam 5. An exposure device 19 for exposure, a developing device 4 which is arranged around the photosensitive member 2 and develops the charged photosensitive member 2 to form a toner image, and a toner image formed on the surface of the photosensitive member 2 An intermediate transfer roller 7 for transferring, a backup roller 8 for generating a pressure necessary for transferring an image on the intermediate transfer roller 7 to the print medium 16, and the transferred print medium are gripped and directed to a paper tray (not shown). And a plurality of gripping rollers 15 transported in the direction of the arrow 12.
[0019]
Here, the developing device 4 has an excess from the surface of the developing roller 20 that forms a toner image using the developing solution supplied from the developing tank 14 via the developing solution supply pipe 12 and the surface of the photoreceptor 2 on which the toner image is formed. And a squeeze roller 21 for removing toner. The removed toner is collected in the developing tank 14 via the developer collecting pipe 13. The developing tank 14 is connected to a concentrated developer supply container (not shown), and the concentrated developer is supplied to the developing tank 14 as necessary.
[0020]
The photosensitive member 2 has a hollow structure, is freely supported in the direction of an arrow 11 around a rotating shaft 24, and has a photosensitive drum 9 having a photosensitive layer formed on the surface, and a plurality of photosensitive drums 9 as shown in FIG. The air introduction hole 26 is disposed, and is fixed to the inside of the photosensitive drum 9 as shown in FIG. 1 and the flanges 22 and 23 constituting both ends along the rotation axis 24 of the photosensitive drum 9. A plurality of cooling fins 10 and a rotating shaft 24 are provided.
[0021]
An image forming process in the apparatus having such a configuration will be described.
[0022]
First, the surface of the photosensitive drum 9 rotating in the direction of the arrow 11 is charged by the charger 3 with a uniform charge applied almost uniformly.
[0023]
Next, an electrostatic latent image is formed on the surface of the photosensitive drum 9 by the exposure beam 5 from the exposure device 19.
[0024]
Further, toner is supplied to the surface of the photosensitive drum 9 by the developing roller 20 of the developing device 4, and the toner adheres to the electrostatic latent image, so that a toner image is formed on the surface of the photosensitive drum 9.
[0025]
The squeeze roller 21 of the developing device 4 has a function of scraping off the excess developer on the photosensitive drum 11, and the developer film thickness after passing through the squeeze roller 21 is very thin.
[0026]
The developer thin film is dried by the air output from the drying mechanism 27 connected to the blower 25.
[0027]
The toner image on the photosensitive drum 9 dried by the drying mechanism 27 is transferred onto the surface of the intermediate transfer roller 7 due to the difference in releasability and further applied between the backup roller 8 and the intermediate transfer roller 7. The image is formed by being transferred to the printing medium 16 by pressure.
[0028]
Here, the intermediate transfer roller 7 is usually heated to about 100 ° C. to about 130 ° C. Accordingly, the photosensitive drum 9 in contact with the intermediate transfer roller 7 is gradually warmed.
[0029]
However, except for printing, the photosensitive drum 9 and the intermediate transfer roller 7 are separated by a mechanism (not shown), and heat is not directly transmitted to the photosensitive drum 9.
[0030]
However, at the time of continuous image printing, the photosensitive drum 9 comes into contact with the intermediate transfer roller 7 to be heated and heated, so that deterioration of the characteristics of the photosensitive layer is inevitable.
[0031]
Next, the flow of air from the drying mechanism 27 will be described with reference to FIG. Air is ejected from a plurality of nozzles (not shown) included in the drying mechanism 27 and introduced into the inside of the photosensitive drum 9 by the inner introduction partition 30.
[0032]
The air introduced into the inside of the photosensitive drum 9 takes heat from the plurality of cooling fins 28 and cools the photosensitive drum 9.
[0033]
Further, the air that has passed through the inside of the photosensitive drum 9 is changed in direction by the outer introduction partition wall 31, flows near the outer periphery of the photosensitive drum 9, and the developing device 4, the developing tank 14, and the exposure arranged in this portion. The apparatus 19 and the charger 3 are cooled and discharged to the outside of the image forming apparatus 1 through a filter 29 attached to the housing 6.
[0034]
The image forming apparatus having such a configuration has a cooling fin inside the photosensitive drum 9 and can introduce the air from the drying mechanism 27 into the inside to suppress the temperature rise of the photosensitive member 2. Thereby, electrostatic characteristics are stabilized and high-quality image output can be maintained.
[0035]
Further, regarding the cooling structure of the photosensitive member 2, by using the air from the drying mechanism 27 and effectively using the space inside the photosensitive drum 9, special power and cooling mechanism are required with a simple configuration. A highly reliable device can be realized.
[0036]
Further, the air that has cooled the inside of the photosensitive drum 9 is changed in direction by a simple outer introduction partition wall 31 so that it flows near the outer periphery of the photosensitive drum 9, so that the outer surface of the photosensitive drum 9 having a large area can be obtained. Can be further cooled.
[0037]
At the same time, by cooling the developing device 4 and the developing tank 14, not only can the characteristics of the developer be stabilized, but also the exposure device 19 whose characteristics are likely to deteriorate as the temperature rises can be cooled. It is possible to realize a stable and highly reliable image forming apparatus.
[0038]
Furthermore, the conventional apparatus has problems such as a complicated structure and increased power consumption due to the addition of a cooling device such as a fan. In this embodiment, the structure is simple and power consumption can be reduced. .
[0039]
In the above embodiment, the image forming apparatus using liquid toner has been described as an example. However, the present embodiment is not limited to the liquid toner but is applied to other types of image forming apparatuses in which the temperature rise of the photosensitive drum is a concern. The cooling structure in the form of can be applied.
[0040]
(2) Second Embodiment An image forming apparatus according to a second embodiment of the present invention will be described. The schematic configuration of the entire image forming apparatus is the same as that of the first embodiment described with reference to FIG.
[0041]
FIG. 4 shows a cross-sectional structure of the photoreceptor in the image forming apparatus of the present embodiment.
[0042]
The photoconductor 2a includes a photoconductor drum 9a, a rotary shaft 24a disposed on both ends of the photoconductor drum 9a via flanges 22a and 23a, and a plurality of cooling fins 34 fixed to the inside of the photoconductor drum 9a. 35.
[0043]
Here, a plurality of air introduction holes 26a are formed in the flanges 22a and 23a. Through this air introduction hole 26a, air from the drying mechanism is introduced into the interior as indicated by arrows 32 and 33 to cool the inside of the photoconductor 29 and led out to the outside.
[0044]
The photoconductor 2a according to the present embodiment includes the cooling fins 34 and 35, thereby increasing the contact area with air and promoting cooling, and actively disturbing the air flows 32 and 33. The heat exchange can be further promoted.
[0045]
Therefore, by further improving the cooling efficiency as compared with the first embodiment, a highly reliable image forming apparatus can be realized with a small and simple configuration capable of high-quality print output.
[0046]
Here, the shape of the cooling fin is not limited. For example, the cooling fin may have a rod-like shape like the cooling fin 34, or a flat plate provided in parallel along the rotation axis 24a like the cooling fin 35. In addition, an air passage hole 35a having an arbitrary shape may be provided.
[0047]
(3) Third Embodiment An image forming apparatus according to a third embodiment of the present invention will be described with reference to the drawings. The schematic configuration of the entire image forming apparatus is the same as that of the first embodiment described with reference to FIG.
[0048]
FIG. 5 shows a cross-sectional shape of the flange portions located at both ends of the photoconductor 50 included in the image forming apparatus according to the present embodiment.
[0049]
In the photoconductor 50 of the present embodiment, the cooling fins 53, 54, 55, 56 having the shape of a plurality of fans are provided between the photoconductor drum 51, the rotary shaft 52, and the photoconductor drum 51 and the rotary shaft 52. It has. Here, the cooling fins 53 to 56 are fixed to the photosensitive drum 51.
[0050]
By having such cooling fins 53 to 56, the photoconductor 50 in the present embodiment can naturally introduce air into the photoconductor drum 51 as the photoconductor drum 51 rotates.
[0051]
Therefore, air can be easily introduced into the interior of the photosensitive drum 51 by the cooling fins 53 to 56 without providing a partition wall such as the inner introduction partition wall 30 described in the first embodiment.
[0052]
Here, since the rotation of the photosensitive drum 51 is necessary as an image forming process, it is not necessary to add new power for cooling, and it is easy with a simple configuration in which only the cooling fins 53 to 56 are provided. The cooling effect of the photoreceptor 50 can be improved.
[0053]
The above-described embodiments are merely examples and do not limit the present invention, and various modifications can be made within the technical scope of the present invention.
[0054]
For example, in the first to third embodiments, the cooling fin is provided inside the photosensitive drum. However, the shape is not limited to the shape of the cooling fin, and various modifications can be made.
[0055]
In the third embodiment, cooling fins 53 to 56 having a fan shape are provided between the photosensitive drum 51 and the rotating shaft 52. However, the present invention is not limited to this shape, and in the air passage hole 35a provided in the cooling fin 35 of the photoreceptor 2a according to the second embodiment, a portion parallel to at least the direction of the rotation axis 24 on the end face is formed on the plate. Since the air can also flow in a desired direction by forming it obliquely with respect to the thickness direction, the cooling effect of the photosensitive member can be improved. Moreover, you may use together the cooling fin which has such an air passage hole, and the cooling fin which has the shape of a fan.
[0056]
【The invention's effect】
As described above, according to the image forming apparatus of the present invention, the air output from the drying mechanism is introduced into the inside of the photosensitive drum, thereby simplifying without adding new power or mechanism for cooling. With this configuration, the temperature rise of the photosensitive member can be suppressed, and as a result, the electrostatic characteristics can be stabilized and high-quality image output can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a perspective view illustrating a schematic configuration of a photoconductor in the image forming apparatus.
FIG. 3 is a cross-sectional view showing the flow of air in the image forming apparatus.
FIG. 4 is a cross-sectional view showing a configuration of a photoreceptor in an image forming apparatus according to a second embodiment of the present invention.
FIG. 5 is an explanatory view partially showing a configuration of a photoreceptor in an image forming apparatus according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 and 50 Photoconductor 3 Charger 4 Developer 6 Housing 9 and 51 Photoconductor drum 10 Cooling fin 12 Developer supply piping 13 Developer recovery piping 14 Developer tank 15 Grasping roller 16 Print medium 19 Exposure device 20 Development Roller 21 Squeeze roller 22 Flange 24, 52 Rotating shaft 25 Blower 26 Air introduction hole 27 Drying mechanism 28 Cooling fin 29 Filter 30 Inner introduction partition 31 Outer introduction partition 34, 35, 53-56 Cooling fin

Claims (5)

A photoconductor that is rotatably supported and has a hollow structure;
A charger for charging the photoreceptor;
An exposure device for writing an electrostatic latent image on the charged photoreceptor;
A developing unit that performs development using a liquid developer on the surface of the photoreceptor on which the electrostatic latent image is written;
A drying mechanism that outputs air to dry the liquid component remaining on the photoreceptor after development;
A transfer device for transferring the dried toner image on the photoreceptor to an image carrier;
On the outside of the drying mechanism and the photoconductor, an inner introduction partition arranged to introduce the air output from the drying mechanism into the photoconductor;
With
The photoreceptor is
An image forming apparatus comprising air inlet holes for taking in the air output from the drying mechanism through the inner introduction partition wall at both ends along the rotation axis, and cooling fins inside. Air introduced into the photoconductor through the air introduction hole provided at one end at both ends of the photoconductor passes through the air introduction hole provided at the other end of the photoconductor. The image forming apparatus according to claim 1, further comprising an outer introduction partition wall disposed outside the photoconductor so that the air is led out to the outside and passes near the outer surface of the photoconductor. . 3. The cooling fin according to claim 1, wherein the cooling fin has a flat plate whose longitudinal direction is parallel to the rotation axis direction inside the photoconductor, and an air passage hole is opened in the flat plate. Image forming apparatus. The image forming apparatus according to claim 3, wherein at least a portion of the end surface of the air passage hole that is parallel to the rotation axis direction is oblique to the plate thickness direction of the flat plate. The photoreceptor is
Having flange portions respectively provided at both ends along the rotation axis;
5. The image forming apparatus according to claim 1, wherein the flange portion includes an introduction portion having a fan shape for introducing air output from the drying mechanism into the inside.

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