JPS61210384A - Rotating body suitable for photosensitive drum of electronic copying machine - Google Patents

Abstract

PURPOSE:To improve heat radiation properties and to rotate a photosensitive drum in a high speed by inserting and setting radiation fins radially into a cylindrical rotating body in the direction of the axial line. CONSTITUTION:Projecting stripes 2 are provided on the inside peripheral surface of a cylindrical rotating body 1 formed with an aluminum alloy by extrusion molding, and fitting grooves 4 for insertion of radiation fins 3 are formed between pairs of projecting stripes 2 and 2. Radiation fins 3 which consist of metallic thin plates like aluminum plates and have a U-shaped section are inserted to fitting grooves 4 and are joined to the body 1 by soldering. Each radiation fin 3 consists of fine 3b-3c different in width W to make the radiation efficiency uniform approximately throughout in the lengthwise direction of the rotating body.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a rotating body suitable for use as an electrostatic photosensitive drum in an electronic copying machine or as a cooling roller for cooling and feeding transfer paper.

2. Description of the Related Art Conventionally, hollow cylindrical rotating bodies made of metal such as aluminum have been generally used as photosensitive drums and cooling rollers of this type.

However, in such photosensitive drums and cooling rollers, the heat dissipation of the rotating bodies that constitute them is poor, and the surface area of drums and rollers is decreasing due to the recent strong demand for downsizing of electronic copying machines. So, the following problem occurs.

The problem to be solved by the invention is that photosensitive drums tend to overheat when heated by corona dischargers or lamps, which can significantly reduce the charging performance of the photosensitive drum, or cause toner to build up on the drum surface. Problems have arisen in that the cooling roller melts and impedes good transfer to copy paper.On the other hand, the cooling capacity of the cooling roller decreases, increasing the amount of heat stored in the roller, causing the transfer from the copying machine to deteriorate. There are some inconveniences such as considerable heat build-up in the paper. Moreover, in the case of a photosensitive drum, after the image is transferred to a transfer paper, the heating and fixing operation of the developed image electrostatically adhered to the transfer paper is performed around the photosensitive drum by closely disposing a heat fixing roll. Attempts have been made to reduce the space required to provide a separate fixing section, which tends to increase the temperature of the drum more and more.

In order to improve the heat dissipation properties of photosensitive drums and cooling rollers, proposals have already been made to integrally form protrusions that act as heat dissipation fins on the inner surface of the rotating body (for example, in Japanese Patent Application Laid-Open No. 1983-1993). -103358 Publication, Utility Model No. 5
6-120566), however, there is a limit to the number of integrally molded fins that can be increased, and it has not been possible to achieve the desired cooling effect.

The object of the present invention is to provide a rotating body that solves the above-mentioned problems. Firstly, by significantly increasing the heat dissipation of the rotating body, it is possible to form an electrostatic latent image by rotation, even when a heating fixing roll is brought into contact with a part of the circumferential surface of the photosensitive drum, for example. Second, when blowing air from one end of the rotating body to promote cooling, the surface temperature of the rotating body must be sufficiently lowered. Thirdly, it is possible to reduce the surface temperature as uniformly as possible over the entire length without creating a temperature gradient between one end and the other end. The purpose is to make it as simple as possible and to make it easier to understand.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention has the structure of a rotating body inside a cylindrical rotating body that serves as a support for a photosensitive layer or a transport support for transfer paper. , U-shaped cross section or V
By inserting heat dissipation fins such as letter-shaped in a radial arrangement along the axial direction, sufficient heat dissipation can be promoted by combining this with a means to promote forced air cooling using a fan from one end of the rotating body. Make it effective.

Furthermore, the height of the radiation fins from the inner surface of the main body is configured to gradually increase from one end of the main body on the cooling air inflow side to the other end, so that the surface temperature in the longitudinal direction of the rotor is increased. Try to reduce the slope. Furthermore, a fitting groove for inserting the fins is formed on the inner surface of the main body to simplify the work of inserting and installing the radiation fins.

That is, the present invention includes a cylindrical main body in which a large number of fitting grooves are formed along the axial direction on the inner surface, and heat dissipating fins including a plurality of types of different widths and shorter than the length of the main body. , the radiation fins are arranged radially into the main body in order from narrow to wide from one end side to the other end of the main body, and with their side edges inserted into the fitting grooves. The heat dissipation fin is configured such that the height from the inner surface of the body gradually increases from one end of the cooling air inflow side of the body to the other end by being inserted and installed in the configuration. The gist of the invention is a rotating body suitable for photosensitive drums for electronic copying machines.

EXAMPLES Hereinafter, examples of the present invention will be described in detail based on the drawings.

In FIGS. 1 to 3, (1) is a rotary body on which a photosensitive layer is formed in the case of a photosensitive drum, and serves as a support conveyance section for transfer paper in the case of a cooling roller. Main body (1
A large number of pairs of protrusions (2) (2>) facing each other in parallel with a predetermined gap are provided along the axial direction on the inner peripheral surface of the protrusions (2). A fitting groove (4) for inserting the radiation fin (3) is formed between 2) and <2). A cylindrical molded body having such a structure can be easily manufactured, for example, by extrusion molding of an aluminum alloy.

The radiation fin (3) is made of a thin metal plate such as an aluminum plate and has a substantially U-shaped cross section, and is inserted into the main body (1) from one end along the axial direction,
Both edges of the open side are inserted and fixed into the adjacent fitting grooves (4) (4). This heat dissipation fin (
The bonding and fixing in 3) is achieved by using aluminum brazing seams 1~ on the radiation fins (3), melting the skin material (brazing material), and brazing the edges on both sides to the main body (1). This is the simplest and most common method. In this case, by crimping a part of the pair of protrusions (2) and temporarily fixing the heat dissipation fin in a pinched state before soldering, the heat dissipation fin will be prevented from falling off during handling until soldering. It is very convenient. Furthermore, brazing may be performed by a method other than bonding, such as by using an adhesive. In this case, as shown in Fig. 4(a), the double-convex strip (2) (
By bending the ends of 2) in opposite directions, or by forming the inner surface of the end into a slope as shown in FIG. It is also recommended to form a

By the way, the heat dissipation fins (3) mentioned above are all attached to the main body (1).
The length is approximately 1/3 of the total length of the
and width (W>).In other words, as shown in FIG. 5, the narrowest first fin (
3a) and a second fin (3a) whose width is wider by a predetermined amount than the second fin (3a).
b) and a third fin (3C) that is wider than this. Thus, the narrow first fin (3a) is connected to the main body (1
), and the second fin (3b) is installed in a radial arrangement on one end side of the main body (1), and the second fin (3b) is connected to the first fin (3a) in the middle part of the main body (1).
The third fin (3C) is connected to the main body (1
) is inserted and installed in a continuous state with the second fin (3b). Therefore, as shown in FIGS. 1 and 2,
The height of the radiation fins (3) from the inner surface of the body increases from one end on the inflow side of the cooling air from the cooling fan (5) arranged facing one end of the rotating body to the other end on the outlet side. is structured so that it gradually increases in stages.

The height, length, arrangement state, etc. of the radiation fins (3) as described above are not limited to the embodiments.

Therefore, for example, two types of radiation fins having a length of approximately 1/2 of the total length of the main body (1) and different widths may be used, or four or more types may be used. Furthermore, multiple types with different widths and lengths may be used.
Alternatively, the number of fins arranged in the circumferential direction may be different for each stage. These matters are appropriately determined from a design perspective in relation to the usage conditions of the rotating body.

FIG. 6 shows another embodiment that is preferably adopted depending on the temperature distribution situation on the surface of the rotating body. In this embodiment, two types of radiation fins (3a') (3b) having different widths are used, except for a length range of approximately 1/3 of the total length of the rotary body (1') at one end on the cooling air inflow side. '
) are inserted in order from the narrowest width (3a') along the axial direction and in a radial arrangement. Therefore, a non-inserted part (6) where no radiation fins (3') are present is formed at one end of the cooling air inlet side from the cooling fan (5'), and the height of the fins increases as it reaches the outlet side. becomes high ε). Here, it is generally preferable that the non-inserted part (6) is formed in a length range of 1/2 or less of the total length of the main body (1) in terms of heat dissipation effect, and about 1/3 of the total length of the main body (1). It is preferable to set it as above.

In the illustrated embodiment described above, a pair of protrusions (2) (2) (2') (2') are provided on the inner surface of the main body (1), and a fitting groove (4) is formed by the protrusions. , but the convex stripe (
2) A concave portion serving as a fitting groove may be formed directly on the inner wall of the main body (1) without providing (2').

In addition, as the heat dissipation fins <3) (3'), we used heat dissipation fins with a substantially U-shaped cross section, but V-shaped cross sections or other bent fins may also be used, or simply flat band-shaped fins may be used. In some cases, In addition, in order to further improve heat dissipation efficiency, the heat dissipation plate part of these fins is
Furthermore, it is also recommended to use a material with corrugations in the transverse or longitudinal direction, or a material with many louver-shaped cut and raised portions.

When the rotating body according to the present invention is used as a photosensitive drum or a cooling roller, for example, the rotating body is rotatably supported as appropriate with both ends opened as wide as possible, and cooling air is supplied by a cooling fan. It is made possible to send it inside. In addition, in the implementation of the present invention, in order to easily perform rotational support of the rotating body, a plurality of tubular inner cylinders that also serve as bearings are provided in the center of the main body (1) and widened apart from the main body (1). It may also be integrally formed by simultaneous extrusion through radial connecting bars.

Effects of the Invention The rotating body according to the present invention has the above-described configuration, and since the heat dissipating fins (4) are present on the inner surface of the rotating body main body (1) in contact with the inner surface, heat dissipating properties are improved. When used as a photosensitive drum, even if the outer cylinder is heated by discharge from a corona-class electric device or by being irradiated with light from a lamp, it quickly dissipates heat and does not cause overheating.
The rotation speed of the drum can be increased to increase the speed. In particular, as shown in Figure 1, by blowing air from one end of the rotating body using a fan (5) to perform forced air cooling, the heat dissipation effect can be easily promoted. Even in cases where the transferred image on the transfer paper is fixed by heat-fixing rows on the circumferential surface, the temperature of the heated outer circumferential surface of the drum must be sufficiently high before it reaches the charging section. This makes it possible to lower the temperature to a low temperature, which is extremely effective in further downsizing copying machines. Also, when used as a heat dissipation roller, the heat removed from the transfer paper can be reliably dissipated before the next transfer paper arrives, allowing the transfer paper to be sent out of the copying machine in a sufficiently cooled state. becomes.

Furthermore, in the cooling promotion effect by the fan (5),
In the rotating body according to the present invention, the heat dissipation fins include a plurality of types of different widths, and the heat dissipation fins are arranged radially in order from narrow to wide from one end of the main body to the other end. By inserting and installing the radiation fins into the main body, the height of the radiation fins from the inner surface of the main body gradually increases from one end of the cooling air inlet side to the other end of the main body, so the length of the rotating body can be increased. The heat dissipation efficiency can be approximately equalized over the entire length in the horizontal direction. Therefore,
There is no large i degree gradient in surface temperature between one end and the other end of the rotating body, and a uniform action can always be maintained over the entire length.

Furthermore, since the heat dissipation fin is inserted and installed with its side edge inserted into the fitting groove of the main body, unlike when it is integrally molded with the main body, the heat dissipation fin is inserted from the inner surface of the rotating body. You can set the height, number of inserts, length, etc. as you like.
Therefore, the heat radiation area can be easily adjusted, and an appropriate heat radiation effect can be ensured depending on the usage conditions of the rotating body. In addition, since the fitting groove allows easy positioning of the heat dissipation fin, the work of inserting and installing the heat dissipation fin into the rotating body body can be easily performed, which is advantageous in terms of manufacturing.

As described above, this invention enables the installation of a large number of heat dissipating fins, which would not be possible when integrally molded on the main body, and provides extremely excellent heat dissipation performance. There is no risk of troubles due to overheating even when used continuously for a long time, and the surface temperature can be controlled to be approximately even over the entire length, maintaining good functionality and making the photosensitive drum and cooling roller itself more compact. In addition to this, it also made it possible to simplify the fixing mechanism by heating and fixing the toner on the transfer paper around the photosensitive drum, which made a huge contribution to the miniaturization of copying machines. It has a remarkable effect that can make a contribution.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line U-II in Fig. 1, and Fig. 3 is an enlarged view showing a state in which a radiation fin is inserted into a fitting groove. Cross section, 4th
The figure is an enlarged sectional view showing another example of the shape of the fitting groove,
Figure 5 is a perspective view showing the state before the heat dissipation fins are inserted;
The figure is a partially cutaway perspective view showing another embodiment of the invention. (1) (1')...Main body, (3) (3')...
Radiation fins, (3a) (3a')''-first fin, (3b) (3b')...second fin, (3C)
...Third fin, (4)...Fitting groove, (6)...
Non-inserted part. Above Figure 5 Figure 6

Claims (2)

[Claims] (1) Includes a cylindrical body with multiple fitting grooves formed along the axial direction on the inner surface, and multiple types of different widths,
heat dissipation fins shorter than the length of the main body, the heat dissipation fins are arranged sequentially from narrow to wide from one end side of the main body to the other end side, and the side edges thereof are fitted into the fitting part. By being inserted into the groove and installed in a radial arrangement inside the main body, the height of the radiation fins from the inner surface of the main body gradually increases from one end of the main body to the other end on the cooling air inflow side. A rotating body suitable for a photosensitive drum for an electronic copying machine, etc., characterized by being configured to be raised high. (2) The electronic device according to claim 1, wherein a non-inserted portion in which no radiation fins are present is formed at one end of the main body on the cooling air inflow side in a length range of 1/2 or less of the total length of the main body. A rotating body suitable for photosensitive drums for copying machines, etc.