JPS59192260A - Photosensitive drum for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To bring a thin developer layer on a developer carrying body easily into secure contact with a photosensitive drum by constituting the drum with an outside layer having an elastic deformable photosensitive body for supporting a photosensitive layer, and an elastic material layer for supporting this outside layer. CONSTITUTION:An elastic material layer 3 is fixed to a rotary shaft 2 in one body, and an outside layer 4 is composed of a photosensitive body support layer 5 and a photosensitive layer 6 formed on the surface of the layer 5. This layer 6 is made of a photoconductive material of an inorg. substance, such as amorphous material, or an org. substance, and the layer 5 is made of an elastic deformable thin metallic plate or the like. The elastic material layer 3 is composed of a nonfoam material, such as rubber, or an elastic foam materials or the like of proper materials. Since this drum 1 has the elastic deformable outside layer 4 and the elastic layer 3, its surface can be elastically deformed when an external force is applied.

Description

[Detailed description of the invention] Technical field The present invention is a photosensitive drum V for electronic copying machines. -Related.

Prior Art A conventional photosensitive drum has a support made of a rigid body and a 7t
The support has n photosensitive layers and Q. The photoreceptor drum that is attached to the main body of the copying machine is rotatable [during copying operation], an electrostatic latent image is formed on the photoreceptor layer of the photoreceptor drum,
This latent image is visualized by a developer in a developing device.

However, the photoreceptor drum is made up of a rigid body like in the past.
Then, for example, the following drawbacks cannot be avoided.

That is, as a developing device, for example, a one-component developer (hereinafter referred to as toner) is placed on a developer carrier consisting of an image roller.
During the transport, the toner particles are charged to a predetermined polarity by contact with, for example, a developing roller, and thus charged, the IJ toner particles r form an electrostatic latent image on the photosensitive drum. In this case, the thickness of the toner on the developing roller should be made extremely thin, and ideally, the toner particles should be uniformly charged on the developing roller.
It is desirable to form one layer of individual thick toners. This is because if the toner on the developing roller is thick, it will not be able to be charged uniformly over the thickness direction, resulting in a risk of deteriorating the quality of the visible image.

On the other hand, a thin layer of toner is formed on the developing roller, and the toner particles? I-In order to transfer the electrostatic latent image on the photoreceptor drum and obtain a high-quality clear image, the toner of the developing roller is brought into contact with the surface of the photoreceptor drum, but at a certain interval? It is necessary to open the opposite awn. However, the photoreceptor drum is 1K.''11
When it comes to the body, the developing roller has a very thin toner layer and the surface of the drum is in contact with the surface of the drum. If the surface of the 1W roller is also made of a rigid body, if the surface of the 1W roller is also made of a rigid body, there may be slight distortion or debris on the circumferential surface of the photoreceptor drum or developing roller. The outer diameter of the drum and the developing roller may be slightly inaccurate due to variations in manufacturing, a, etc. On the other hand, the two may press against each other with excessive force, causing scratches on the surface of the photoreceptor drum. Distortion of the surface of the developing roller or photoreceptor drum, or variations in its outer diameter. It is difficult to produce high-precision products such as 4-1 without completely eliminating the glare.To eliminate this disadvantage, a photoreceptor belt is used instead of the photoreceptor drum, and the developing roller is pressed into contact with this belt. By bending the belt, it is also possible to bring the developing roller into contact with the photoreceptor belt.
Ru. However, when the photoconductor bell LF-G is used, this 1% k
It requires at least two rollers to hold the same length, which not only complicates this one-piece configuration and increases cost, but also
There is no excuse for the disadvantages of larger copy machines.

Purpose The present invention is not based on the above recognition, and its purpose is to completely eliminate distortion of the surface of the developing roller or photoreceptor drum, or irregularities in the outer diameter. It is an object of the present invention to provide a photoreceptor drum which does not suffer from the defects described above even if the holes are not manufactured with high precision.

Embodiments The present invention abandons the conventional idea that the entire photoreceptor drum is composed of 1N (11 members), and proposes a structure in which the surface of the photoreceptor drum can be elastically deformed. Will it be implemented?]” Shunshi explains according to the four aspects.

FIG. 1 is a schematic diagram showing an example of an electronic copying machine for photosensitive drums according to the present invention. An elastic material layer 3 supported by a rotary shaft 2 made of a rigid body rotatably held in the machine body, and a sleeve-shaped outer layer 7 fixedly mounted on the outer peripheral surface of the machine. 4.The surface of the drum 1 is elastically deformed as described later when an external force is applied to the drum 7'1.However, when no external force is applied, the surface of the drum 1 deforms elastically as shown in FIGS. As shown, the elastic material layer 3 and the outer layer 4 have a cylindrical shape concentric with the rotating shaft 2. In this example, the elastic material layer 3 is not integrally fixed to the rotating shaft 2. As shown in FIG. 4, the outer layer 4 consists of a photoreceptor support layer 5 and a photoreceptor layer 6 formed on the surface of the support layer 5 by, for example, coating. Like the photosensitive layer in the photosensitive drum,
Examples include OPC, zinc oxide, selenium, amorphous materials, and other inorganic or organic materials.
I'm here. The photoreceptor support layer 5 is made of an elastically deformable material, such as a thin plate of metal, and in this example, the support layer 5 is made of an electrically conductive material (usually having a volume resistivity of 10 gΩ-) as in conventional photoreceptor drums. Nishiki (below) to the old composition, TeQ・
Ru.

The constant elasticity material layer 3 is made of an elastic number A material such as a non-foamed material such as rubber, or a foamed material (including sponge) made of a suitable material. As described above, the photoreceptor drum has the outer layer 4 capable of elastic deformation and the elastic phase layer 3, and as described above, external force is applied to the surface of the photoreceptor drum. , the surface can be elastically deformed.

During the copying operation, the photoreceptor drum 1 is rotated in the clockwise direction f (not shown) by the driving device (not shown) in the clockwise direction (f) in FIG.
The photosensitive layer 6 of the drum 1 is charged to a predetermined polarity 712 by the charger 7, and the charged portion is irradiated with light 8 (not shown) from the document force to generate an electrostatic potential corresponding to the image of the document t1. A force for forming an image is applied to the circumferential surface of the developing roller 10 as a developing electrode in the developing device @9, which is supplied from a tank (not shown). ,7. ” Toner (−
A thin layer 11 of a component-based developer is formed on the surface of the developing roller. What should I do?

As is well known, the toner thus transported is charged to a predetermined polarity (usually a polarity opposite to that of the photosensitive layer 6) by contact with the surface of the developing roller. At this time, the thickness of the toner layer 11 of the developing roller 10-H (extremely thin, particle size 5 to 0) is equivalent to one or two fine toner particles of about 0 μm.
Once the thickness is about the same as that of a single particle, the charging tip H' is uniformly charged over the entire thickness. The charged awn'rly
The toner from F reaches the opposing area between the photosensitive drum 1 and the developing roller 10, and the toner on the developing roller 1H electrostatically transfers to the electrostatically deposited image V'C on the drum 1, making the latent image visible. After image transfer 1. Ru. In this case, the developing roller 10 is not pressed against the photoreceptor drum, and therefore the roller 10 is not pressed against the photoreceptor drum.
The portions of the surface of the photoreceptor drum in the vicinity of B1 and B7, which are in contact with each other through the VCI, are elastically deformed (1) in the radial direction of the tram in a four-person ladder state. You yx,
Developing 1 Cola 10-hi toner (total, 7 g) of extremely thin G1 reliably contacts the surface of the photoreceptor drum.

As for the first structure for conveying the developing roller 10 [carrying awn 7 + "17", T toner R, for example, a magnet (ln1 not shown) may be installed inside the roller 10, and the surface of the roller] 0 It is well known that the toner may be conveyed by using frictional breakage between the toner and the toner. It is also possible to have a month of 0. When the developing roller and the magnet are in the same position, it is also well known that instead of rotating the developing roller R, the magnet can be rotated, or the developing roller and the magnet can be rotated together. The direction of rotation can also be selected as appropriate.

As mentioned above, the Buddha image formed in the hole fJ on the photoreceptor drum If is
Supply to the surface of drum 1? The transfer charger 13 is transferred to the eyebrow R transfer paper 12, and the transfer awn is 71. ．． In the next step U), the transfer paper 12 is separated from the surface of the drum 1 by, for example, 7% by a separation charger 14 as shown in the figure. It goes without saying that the separation charger 14VC or G may be used together with the separation claw r (not shown) to separate the transfer paper.

The toner remaining on the surface of the photoreceptor drum after the visible image is transferred is
For example, as shown in the figure, a 7"1.
1 cleaning play 1-15 K remover 7″
l,ru. You can also use it instead of a blade (such as a flan, fur brush, etc.). 20 is a charger for eliminating static electricity.

The developing roller 10 and the blade 15 are in pressure contact with the photosensitive drum 1, and the drum portion 7 is deformed, but the roller 10 and the blade are adjusted against the ram 1 so that this deformation remains within the elastic deformation limit] Setting of pressure contact state of 5 - J 7"1.ru0 Normally, the amount that the drum 1 is shaped in the radial direction by the developing roller 1ovc (the amount of dent 9ΔZ is, for example, about 0.1 to 0.5 mm) , the blade 15 can also keep the deformation amount ΔZ' to 0.57 ura or less, for example.

From the above-mentioned configuration f, the surface of the photoconductor drum 1 is elastically deformable by four people.
Due to the elastic deformation in the radial direction, the circumferential surfaces of the tram 1 and the developing roller 10 are somewhat eccentric with respect to the central axis of the tram 1, and the outer diameter of the holes 1/j ``Due to some manufacturing variations, even if at least the surface of the developing roller 10 is made of a rigid body, the developing roller 10 can be used without any inconvenience caused by scratches on the drum surface or the developing roller surface. Due to the fact that the toner can come into contact with the photoreceptor drum 1 more reliably and stably than in the past, a large gap is formed between the toner on the roller 10 and the surface of the drum 1, resulting in a visible image failure. The problem is to suppress the decline. 1, the developing roller lOt does not come into contact with the surface of the drum 1 through the toner r, but if it is constructed so that the toner is placed against the surface of the drum 1 with a small gap r, the 1g of both
It is possible to prevent the 1st gap from becoming too large. Of course, when the drum 1 and the roller 10 are arranged close to each other, even if a part of them abuts each other at 2 through the toner and R, the drum 1
There is no force that could damage the drum or barge roller because it is only elastically deformed.

By the way, if the above-mentioned photosensitive drum 1 is configured to be elastically deformed, the external pressure acts on the drum 1 only at a portion, or at this portion and a portion in the vicinity thereof, as shown in FIG. It is desirable that the other parts be deformed. As shown in FIG. 5VC, the entire photoreceptor drum 1 is deformed, for example, when a document is released. If the photoreceptor drum portion C (see Fig. 5) subjected to exposure-a3 is deformed by step 8, it is not possible to properly focus an image on this portion C, and the visible image formed by this ``L'' is There is a fear that it will become unclear.

Also, if the visible image r is transferred to the transfer paper 12 and the drum portion D (FIG. 5) separated from the surface of the drum 1 (FIG. 13a.

14a to the surface of the drum 10 becomes inconsistent, the transfer of the visible image cannot be performed reliably, and there is a risk of causing disturbances in the visible image on the transfer paper, or causing mistakes in separating the transfer paper 12. . In this way, the photoreceptor drum 1 is constructed so that only the portion on which external pressure is applied and the portions in the vicinity thereof are deformed, and other drum portions are designed so that they are not affected by the external pressure acting on the drum. Or even if it is received,
The amount of deformation in the radial direction of the drum is at most (), l to 0.
．． It is desirable to keep it below 5 pharynges. It is advantageous to construct a haze that satisfies such requirements, for example, as follows.

Figures 6 and 7 are explanatory diagrams showing the principle.
The figure shows only the sleeve-shaped outer layer 4, and FIG. : 7% of each elastic material layer is shown. Now, as shown in FIG. 6, for a single outer layer 4,
An external force r called FA is applied by the pressurizing member 16 in the diametrical direction, and the portion to which this external force is applied is bulged in the radial direction πΔZ, and the portion R is swung in the radial direction.

At this time, the outer layer 4 is made of metal, for example, and has a structure of 1.
When the external force FA is applied, the outer layer 4 deforms as a whole, and as shown by the dashed line in FIG.

On the other hand, both ends r of the rotating shaft 2 shown in FIG. Let k be the amount of radial VCC compression deformation. In this case, the elastic material layer 3 is made of a non-foamed or foamed elastic material such as rubber. It is normal to deform, but other parts do not substantially deform. In this case, the forces FA and FB necessary to deform the outer layer 4 and the elastic material layer 3 by the same amount ΔZ should satisfy the relationship FA <F"B, preferably FA < FB. , (7≧n) If the outer layer 4 is more elastically deformable than the elastic material layer 3, the outer layer 4r is attached to the elastic material layer 3.
When pressure is applied to the upper body drum L (Figure 11), the layer 4 deforms so as to follow the elastic material layer 3 VC as shown in Figure 1. The circumferential surface of the drum 1 does not have an overall KK shape as shown in the fifth factor. Therefore, when an external force is applied, only the surface portion of the tγS drum and the vicinity of 7 are elastically deformed, and the other drum portions (all or almost no deformation), and the requirements explained in the previous VC can be satisfied. On the other hand, to obtain the same amount of deformation ΔZt,
If B"A>FB, the drum 1 will be deformed as shown in FIG.

As for the material of the outer layer 4, more precisely, the photoreceptor support layer 5, on which two drops of FA<F'B can be applied as described above,
For example, nickel, stainless steel, aluminum ram, etc. can be mentioned. In this case, since nickel and stainless steel have relatively large yield strength and longitudinal elastic modulus, when the photoreceptor support layer 5r is manufactured from these materials, the total thickness is 1
It is desirable to set it to 00μ or less. Junmikai 100μ
If it is set to be thicker, the outer layer 4r will be difficult to deform unless the photoreceptor drum is exposed to a large amount of external pressure. The choice of material for the material layer 3 is limited, and as a result, the photoreceptor is easily deformed into an undesirable state as shown in FIG. 1 The outer layer 4 of the sex body support layer 5 is made of aluminum, in which case the yield strength of aluminum is
Since the modulus of longitudinal elasticity is smaller than that of nickel or stainless steel, its thickness is preferably slightly thicker (L7 or less), and according to experiments (according to
Go. In this way, it is desirable that the thickness of the photoreceptor support layer 5 be made quite thin. However, no matter what material the photoreceptor support layer 5r is made of, the outer layer 4 will completely restore its original sleeve-like shape when an external force is removed. Since it is desirable, the thickness of the photoreceptor support layer 5?
It goes without saying that the thickness should be set so as not to make it too thin and cause plastic deformation.

For the photoreceptor support layer 5 of the outer layer 4, the material as exemplified above is used, and its thickness tj is selected as shown below.71. For example, the material of the elastic material layer 3 that satisfies the above-mentioned condition 2, FA < FB, can be widely selected from ordinary non-foamed rubber, appropriate foam, and the like. In the case of seven,
When an external pressure is applied to the elastic phase layer 5π, n7-, the external pressure is absorbed at the 7 part or J and its neighboring parts, as shown in FIG. is the force transmitted in,, vc < not only the amount of elastic deformation, but also the hardness and the external pressure removed, zt, ′
f: When the elastic material layer β has the property r that it can be restored to its original cylindrical shape, select a material tray that will not permanently deform even if external pressure is applied to the elastic material layer 3 for a long time. Of course, this is desirable. According to experiments, rice (il I(+ogers) is used as the material for the elastic material layer 3.
Polyurethane foam manufactured by Corporation under the trade name Microcell Rubber? Favorable results were obtained when using eyebrows. The hardness is rubber 1? g! It was 20 degrees with a JIS C type degree meter.

This microcellular rubber was compressed to a thickness of 50 cm, and then left at a temperature of 1158°F for 22 hours. After that, the pressure was released and the first rad was pressed. A permanent compressive strain of 10 cm remains, but this is quite small compared to the permanent compressive strain of ordinary foam, which is about 30%.
2 shows that im suitable, good eyebrows, R material.

In addition, a sleeve-shaped photoreceptor support layer 5 made of nickel with a thickness of 50 μm is used, and the outer layer 4 is fitted with the cylindrical elastic material layer 3'+c made of the above-mentioned microcell rubber. The outer diameter t11 of the elastic material layer 3 before fitting is set 1 wn larger than the inner diameter of the outer side 4, and the elastic material layer 3 after fitting is set to have a radius of VC+1.5wo over its entire circumference.
A prototype photosensitive drum 1 was manufactured by compression, and it was installed in a copying machine as shown in Fig. 1 for experiments. As a result, a desirable deformed state of the drum as shown in Fig. M1 was obtained. I can do it.

In another experiment, the hardness of microcell rubber was 7″lr.
By making the drum more deformable than in Figure 1, the deformation pattern of the drum as shown in Figure 1 can be obtained. Can this hardness be lowered? ! If the tension is lowered too much, the thickness of the photoreceptor support layer 5 will become extremely thin due to stiffness, and the bending 71 will not be possible, resulting in plastic deformation of the eyebrows, and conversely, the hardness of the elastic material layer 3 will deteriorate. If the pressure is set too high, the photosensitive drum 1 will deform and become scratchy, so it is practically advantageous to set the hardness (C type) of the elastic material layer 3 to 5 to 50 degrees.

Although the basic embodiments of the present invention have been described above, it is obvious that the present invention can be constructed by making various modifications to the above-mentioned components.

For example, in the above specific example, the case where the photoreceptor supporting layer 5 is made of metal etc. and the deformed state of this alone becomes as shown in FIG. 6 has been described. Five supporting layers may be made of rubber or the like. Sword f,
The T photoconductor drum is made up of only a perforated elastic material layer supported at a rotation of 1M++, and an outer layer, and the drum surface is deformed. For example, suitable layers other than the outer layer and the outer layer may be added as necessary.Also, the outer layer is not composed only of the photosensitive layer and its photoreceptor support layer. For example, as shown in FIG. 8, an intermediate layer 17 of a conductive material having a specific volume resistivity of 09Ω-brocade or less is provided between the photosensitive layer 6 and the photosensitive member support layer 5,
As is well known, the number may be 17 to suppress a decrease in sensitivity of the photosensitive layer 6. The intermediate layer 17 may be made of 7t-aluminum or other suitable inorganic or organic phase material deposited on the photoreceptor support layer 5.

As is well known, in order to form an electrostatic latent image on a photoreceptor drum, it is necessary to care for the photoreceptor support layer 5 or intermediate layer 17, but for this purpose, the photoreceptor In order to avoid inhibiting the deformation of the drum 1, it can be grounded via a conductor such as the photoreceptor support layer 5 or the intermediate N17 (as shown in the figure).

In that case, the rotating shaft 2 is made of a conductor, and the rotating shaft 2 is connected to the photoreceptor support layer 5 or the intermediate layer 17 with a conductor made of a thin wire or foil and grounded. It is also possible to embed the conductors in the elastic material layer 3 in a deformable state.
If the elastic material layer is made of a conductor, for example, conductive rubber, the intermediate layer or photoreceptor support may be grounded without using the thin wire or foil described above. Furthermore, as can be seen from the above-mentioned rx section, an intermediate layer 17 made of a conductive material is provided, and this layer 7'' is grounded.
The photoreceptor support layer itself may be made of an insulating material such as insulating rubber.

1k, the outer layer 2 may be fixed to the elastic layer #J with an adhesive or the like, but the outer layer 4 can be easily removed. C
Additional advantages can also be obtained by simply replacing the outer layer if the opening is provided. In this case, when the photoreceptor drum is used, the sum ΣF of external forces applied to the drum in the tangential direction of the drum by, for example, the developing roller, cleaning blade, separating claw, etc., and the friction acting on the elastic material layer and the outer layer. The force f should satisfy the relationship 2, f>EF, and the outer layer should not move relative to the elastic material layer. In order to satisfy this condition, in addition to increasing the friction coefficient between the P property layer and the outer layer, as shown in the previous experimental example,
It is also advantageous to make the outer diameter of the elastic material layer before the elastic material layer and the outer layer string-fitted to be larger than the inner diameter of the outer layer. -1R elastic 4 material layers can be fixed to the rotary shaft by using an adhesive or the like, or when molding the elastic 41 material layers, the elastic material can be used integrally with the rotary shaft. It is also possible to form a material layer.

Effects According to the present invention, since the surface of the photoreceptor drum can be elastically deformed, the effect of the present invention is that the surface of the photoreceptor drum can be elastically deformed. It has also become possible to easily and reliably position the developer in contact with the photoreceptor drum, or with a small gap between the developer and the photoreceptor drum.

[Brief explanation of drawings]

FIG. 1 is an explanatory partial cross-sectional view showing an example of an electronic copying machine using a g-photo drum according to the present invention, and FIG. 2 is a cross-sectional view of the photoreceptor drum when no external force acts on the photoreceptor drum ,
Fig. 3 is a sectional view taken along the line Iff-III in Fig. 2, and Fig. 4 is a sectional view taken along the line Iff-III in Fig. 2. FIG. 5 is an explanatory diagram similar to FIG. 1 showing the ingenious (1) deformation state of the photoreceptor drum, and FIG. 6 is an enlarged sectional view taken along the line J-IV. FIG. 7 is an explanatory cross-sectional view showing an example of a deformed state, and FIG. FIG. 8 is a sectional view similar to FIG. 4 in another embodiment, and shows the deformed state of the photosensitive drum, outer layer, or elastic material layer in FIGS. 1, 5, 6, and 7. It is exaggerated. ■... Photosensitive drum 3... Elastic material layer 4...
・Outer layer 5...Sensitizer support layer Fig. 5 Fig. 6 Fig. 7 Fig. 8

Claims (10)

[Claims] (1) A photosensitive drum for an electronic copying machine, comprising an outer layer having a photosensitive layer on the surface and an elastically deformable photosensitive support layer supporting the photosensitive layer, and an elastic material layer supporting the outer layer intermittently. . (2) The photoreceptor drum according to claim 1, wherein the photoreceptor support layer is made of stainless steel. (3) The photoreceptor drum according to claim 1, wherein the photoreceptor support layer is made of nickel. (4) The photoreceptor drum according to claim 2 or 3, wherein the photoreceptor support layer has a thickness of 100 μm or less. (5) The photoreceptor drum according to claim 1, wherein the photoreceptor support layer is made of aluminum. (6) The photoreceptor drum according to claim 5, wherein the photoreceptor support layer has a thickness of 200 μm or less. (7) The photosensitive drum according to any one of claims 1 to 6, wherein the elastic phase material layer is made of non-foamed rubber. (8) Any one of claims 1 to 6, in which the elastic material layer is made of a foam. Photosensitive drum Q described in (9) The photosensitive drum according to claim 8, wherein the elastic material layer is made of polyurethane foam. (10) Measure the hardness of the polyurethane foam using a comb hardness tester J
The photosensitive drum according to claim 9, which is an ISO type and is set at 5 degrees to 50 degrees.