Method for deposition onto a substrate and method for producing photo conductor

Abstract

A grounded vacuum container is filled, the container containing a plurality of substrates, with a CVD gas. A voltage is applied to the substrates to generate plasma around each of the substrates along with grounding a plurality of ground members arranged at positions opposite to the deposition surface of each of the substrates inside the vacuum container. A coating is deposited onto a plurality of substrates in a method for deposition that attracts ions within the plasma to the substrates and deposits a coating onto the substrates.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for deposition onto a substrate and a method for producing a photo conductor. These are utilized for, for example, a photo conductor used in electrophotographic copying machines and printers.

2. Description of Related Art

Conventional plasma CVD methods are known that change the raw gas used for the deposition into plasma by applying high-frequency electric power or a high-power voltage pulse and high-frequency electric power, expose substrates to this plasma, and then deposit a coating onto the substrate. (As an example refer to Related Art 1 and Related Art 2.)

Furthermore, manufacturing methods of the photo conductor used in electrophotography which use plasma CVD methods are also known. This photo conductor is comprised by an optically conductive layer that includes an amorphous crystal material with a base material of silicon atoms or a protective surface layer that includes amorphous crystal carbon containing hydrogen atoms. (As an example refer to Related Art 3.)

• • [Related Art 1] Japanese Patent Laid-open Publication H7-278822
  • [Related Art 2] Japanese Patent Laid-open Publication 2001-26887
  • [Related Art 3] Japanese Patent Laid-open Publication 2002-123023

When depositing a coating onto a plurality of substrates using a plasma CVD method with conventional technology, a problem of uneven deposition onto the substrates occurs within the substrates or between the substrates due to a circulating condition of the raw gas used for the deposition or the positional relationship between the vacuum containers that hold the substrates.

The occurrence of this type of uneven deposition is the cause of further problems in substrates used for the photo conductor. Namely, uneven deposition causes both unevenness in the coating thickness of the protective surface layer as well as unevenness in the sensitivity and residual potential of the photo conductor. When this type of unevenness in the coating thickness of the protective surface layer occurs, problems such as uneven density and fogging in images formed on this photo conductor will occur.

SUMMARY OF THE INVENTION

The present invention takes these problems into consideration and has an objective of providing a method for deposition onto a substrate and a manufacturing method of a photo conductor that uses this method for deposition that can reduce uneven deposition onto individual substrates when depositing coatings onto a plurality of substrates and can also reduce unevenness in the coating thickness of the protective surface layer of each photo conductor when forming protective surface layers on a plurality of photo conductors.

The present invention fills a grounded vacuum container, that contains a plurality of substrates, with CVD gas and then simultaneously applies a voltage to the plurality of substrates to generate plasma around each of the substrates along with grounding a plurality of ground members arranged at positions opposite to the deposition surface of each substrate inside the vacuum container when depositing a coating onto a plurality of substrates in a method for deposition that attracts ions within the plasma to the substrates and deposits a coating onto the substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed description which follows, with reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

FIG. 1 shows the composition of the periphery of the image forming unit in an image forming apparatus wherein a photo conductor is applied that utilizes a substrate deposited onto a substrate by the method for deposition related to the first embodiment of the present invention;

FIG. 2 is an enlarged view showing the composition of the photo conductor related to the first embodiment;

FIG. 3 is an outline of an example of a CVD deposition apparatus used when implementing the method for deposition onto a substrate related to the first embodiment;

FIG. 4 shows a view from above the vacuum container of the CVD deposition apparatus shown in FIG. 3;

FIG. 5 shows an example of CVD gas and applied voltage utilized when forming a protective surface layer of the photo conductor in the CVD deposition apparatus shown in FIG. 3 and FIG. 4;

FIG. 6 is a model view showing the distribution of the electric field when four substrates are arranged inside the vacuum container of the CVD deposition apparatus related to the first embodiment;

FIG. 7 is a model view showing the distribution of the electric field when four substrates are arranged inside the vacuum container of the CVD deposition apparatus related to the first embodiment;

FIG. 8 is a model view showing the distribution of the electric field when one substrate is arranged inside the vacuum container of the CVD deposition apparatus related to the first embodiment;

FIG. 9 is a model view showing the distribution of the electric field when one substrate is arranged inside the vacuum container of the CVD deposition apparatus related to the first embodiment;

FIG. 10 shows an example of results obtained when depositing a coating onto a substrate by the method for deposition related to the first embodiment;

FIG. 11 is an outline of an example of a CVD deposition apparatus used when implementing the method for deposition onto a substrate related to the second embodiment of the present invention;

FIG. 12 shows a view from above the inside of the vacuum container of the CVD deposition apparatus shown in FIG. 11;

FIG. 13 is a model view showing the distribution of the electric field when one substrate is arranged inside the vacuum container of the CVD deposition apparatus related to the second embodiment;

FIG. 14 shows an example of a Paschen curve utilized when the method for deposition onto a substrate related to the third embodiment controls the gas pressure while plasma generates in proportion to the distance between the substrate and the ground member;

FIG. 15 shows a fixed region of a Paschen curve utilized when controlling the gas pressure while plasma generates in the method for deposition onto a substrate related to the third embodiment;

FIG. 16 shows an example of multiplication values between gas pressure and distance (distance between substrate B and ground member 1101) in the method for deposition onto a substrate related to the third embodiment;

FIG. 17 shows effects obtained when adjusting the gas pressure supplied to the vacuum container while plasma generates in the CVD deposition apparatus related to the third embodiment; and

FIG. 18 shows effects obtained when adjusting the high-frequency output to the substrate while plasma generates in the CVD deposition apparatus related to the third embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiments of the present invention are explained in the following, in reference to the above-described drawings.

First Embodiment

FIG. 1 shows the composition of the periphery of the image forming unit in an image forming apparatus wherein a photo conductor (hereinafter referred to as photosensitive material) is applied that utilizes a substrate deposited onto a substrate by the method for deposition related to the first embodiment of the present invention. Furthermore, in the following the member whereon a carrier generation layer and a carrier transport layer are deposited onto a conductive base material is referred to as a “substrate” in this specification.

As shown in this figure, an electric charging device 102 close to the photosensitive material 101, an exposure apparatus 103, a developing apparatus 104, and a transfer apparatus 105 are arranged in the related image forming apparatus. The photosensitive material 101 has a protective surface layer. The composition of the related protective surface layer will be described later. The photosensitive material 101 rotates in the direction of the arrow shown in the figure by a drive mechanism not shown in the figure.

The electric charging device 102 uniformly charges the surface of the photosensitive material 101. Although this figure shows the electric charging device 102 that uniformly charges the surface of the photosensitive material 101 using a non-contact electric charging method, the charging is not limited to this and a device that uses a contact electric charging method can also be applied. The exposure apparatus 103 exposes the electrically charged surface using laser light. A latent image is formed on the surface of the photosensitive material 101 by this action. The developing apparatus 104 supplies a non-magnetic developing agent (toner) to an internal developing roller 106 and then adheres a fixed amount of toner to the latent image formed on the surface of the photosensitive material 101. The transfer apparatus 105 transfers the toner adhering to the latent image to a recording paper 108 that is transported by a feed roller 107.

A cleaning apparatus 109 is arranged on the downstream side of the transfer apparatus 105 in the direction of rotation of the photosensitive material 101. The cleaning apparatus 109 removes toner remaining on the surface of the photosensitive material 101 after transfer to the recording paper 108. The cleaning apparatus 109 is provided with a cleaning blade 110 that makes direct contact with and removes toner remaining on the surface of the photosensitive material 101.

FIG. 2 is an enlarged view showing the composition of the photosensitive material 101 related to the first embodiment.

As shown in this figure, the photosensitive material 101 related to the first embodiment is comprised such that a carrier generation layer 202 and a carrier transport layer 203 are deposited onto a conductive base material 201 and a protective surface layer 204 is deposited onto that. The protective surface layer 204 has a two layer construction of a first protective surface layer 205 and a second protective surface layer 206. These first and second protective surface layers 205 and 206 are formed in the photosensitive material 101 that has the protective surface layer related to the first embodiment by a plasma CVD method.

FIG. 3 is an outline of an example of a CVD deposition apparatus used when implementing the method for deposition onto a substrate related to the first embodiment. FIG. 4 shows a view from above the vacuum container of the CVD deposition apparatus shown in FIG. 3. FIG. 5 shows an example of CVD gas and applied voltage utilized when forming the first protective surface layer 205 and the second protective surface layer 206 of the photosensitive material 101 in the CVD deposition apparatus shown in FIG. 3 and FIG. 4.

As shown in FIG. 3, a CVD deposition apparatus 300 is provided with a grounded vacuum container 301. A plurality of substrate holders 302 that hold the substrates B are provided on the inside of the vacuum container 301. A high-frequency power supply 303 and a bias voltage pulse power supply 304 are connected to the substrate holders 302. A superimposed voltage including a bias voltage pulse and a high-frequency voltage pulse is applied to the substrates B through these substrate holders 302.

Because a superimposed voltage including a bias voltage pulse and a high-frequency voltage pulse is applied to a plurality of substrates B in this type of embodiment, ions within the plasma generated around the periphery of each of the substrates B can be reliably attracted to the substrates B. This will be described later.

A gas introduction port 305 is provided on the CVD deposition apparatus 300 to introduce CVD gas from the top of the inside of the vacuum container 301. A discharge port 306 is also provided that discharges to a vacuum container 301 CVD gas that is introduced from the gas introduction port 305.

The CVD deposition apparatus 300 has a plurality of ground members 307 which enclose each of the substrates B held in the plurality of substrate holders 302. Each ground member 307 is grounded by being connected to the vacuum container 301. The relationship between the length of the ground members 307 (“L1” in FIG. 3) and the length of the substrate B (“L2” in FIG. 3) is set such that L1 □ L2. Since the length L1 of the ground members 307 is at least 2 times longer than the length of the substrate B in this manner, the electric field around the periphery of the substrates B extending along the entire length of the substrates B is made uniform. This will be described later.

As shown in FIG. 4, the ground members 307 are cylindrical and are arranged close to the substrates B. By arranging cylindrical ground members 307 close to the substrates B in this manner, the electric field around the periphery of the substrates B can effectively be made uniform compared to when the ground members 307 have other shapes.

The ground members 307 are further arranged such that the distance between adjacent substrates B, from among the plurality of substrates B arranged in the vacuum container 301, becomes constant. The relationship of the distance between adjacent substrates B (“D2” in FIG. 4) and the distance between these substrates B and the vacuum container 301 (“D1” in FIG. 4) is set such that D1 □ D2 at the ground members 307 close to the vacuum container 301. Since the distance D1 between the substrates B and the vacuum container 301 is at least 2 times farther than the distance D2 between the substrates B and the ground members 307 in this manner, the electric field around the periphery of the substrates B can be determined using the positional relationship between the ground members 307. Because of this, the electric field around the periphery of the substrates B can be made uniform without influencing the vacuum container 301. This will be described later.

When forming a protective surface layer in this type of CVD deposition apparatus 300, the surface of the substrate B held in the substrate holder 302 is cleaned using hydrogen gas etching before forming the first protective surface layer 205. In more specific terms, the surface of the substrate B is cleaned by introducing hydrogen gas from the gas introduction port 305 and applying a high-frequency pulse voltage and a bias pulse voltage of −500 V to −1,000 V to the substrate B. This type of cleaning operation can remove foreign matter on the surface of the substrate B and improve the adhesiveness between the carrier transport layer 203 and the first protective surface layer 205 even more. The first protective surface layer 205 and the second protective surface layer 206 form after the surface of the substrate B is cleaned in this manner.

As shown in FIG. 3, when forming the first protective surface layer 205, a hydrocarbon gas, such as methane, is introduced from the gas introduction port 305 as a CVD gas. A superimposed voltage including a negative bias voltage pulse and a high-frequency voltage pulse is applied to the substrate B when hydrocarbon gas has filled the inside of the vacuum container 301. Applying a high-frequency voltage pulse to the substrate B changes the hydrocarbon gas inside the vacuum container 301 into plasma whereafter collisions between the electrons within the plasma and the hydrocarbon gas decompose the hydrocarbon gas and generate ions while the generated ions are attracted to the substrate B and the first protective surface layer 205 forms by applying a negative bias voltage pulse to the substrate B.

As shown in FIG. 3, when forming the first protective surface layer 205, the CVD deposition apparatus 300 applies a bias voltage pulse of −500 V to −2,000 V to the substrate B. Because of this, the ions generated by applying the high-frequency voltage pulse are attracted to the substrate B and a portion of the ions are also injected into the carrier transport layer 203 that comprises the surface of the substrate B. In other words, carbon is injected into the carrier transport layer 203 although the first protective surface layer 205 does not simply adhere to the carrier transport layer 203. The first protective surface layer 205 is formed along with a mixing layer (transition layer) on the carrier transport layer 203. At this time, the first protective surface layer 205 is formed on the surface of the substrate B by amorphous carbon accompanied by an ion injection layer with a membrane thickness of 0.01 μm to 0.1 μm.

In contrast, as shown in FIG. 3, when forming the second protective surface layer 206, hydrocarbon gas diluted by hydrogen (hereinafter referred to as hydrogen diluted hydrocarbon gas) is introduced from the gas introduction port 305. A superimposed voltage including a negative bias voltage pulse and a high-frequency voltage pulse is applied to the substrate B when hydrogen diluted hydrocarbon gas has filled the inside of the vacuum container 301. Applying a high-frequency voltage pulse to the substrate B changes the hydrogen diluted hydrocarbon gas inside the vacuum container 301 into plasma whereafter collisions between the electrons within the plasma and the hydrogen diluted hydrocarbon gas decompose the hydrogen diluted hydrocarbon gas and generate ions while the generated ions are attracted to the substrate B and the second protective surface layer 206 forms by applying a negative bias voltage pulse to the substrate B.

As shown in FIG. 5, when forming the second protective surface layer 206, the CVD deposition apparatus 300 applies a bias voltage pulse of −500 V to −1000 V, smaller than when forming the first protective surface layer 205, to the substrate B. This case is different from the first protective surface layer 205 whereby the ions generated by applying the high-frequency voltage pulse are attracted to the substrate B but a portion of the ions are not injected onto the surface layer of the substrate B. The ions attracted to the substrate B deposit on the surface of the first protective surface layer 205, that comprises the surface layer of the substrate B, and form the second protective surface layer 206. At this time, the second protective surface layer 206 is formed on the surface of the substrate B (the first protective surface layer 205) by an amorphous carbon deposition layer with a membrane thickness of 0.1 μm to 2.0 μm.

When forming the first protective surface layer 205 and the second protective surface layer 206 (when depositing a coating onto the substrate B) in this manner, the ground members 307 are grounded in this CVD deposition apparatus 300. Because of this, the distribution of the electric field around the periphery of the substrate B is made uniform and the state of the plasma around the periphery of each of the substrates B is also made uniform. As a result, unevenness in the coating thickness of the protective surface layer (unevenness when depositing coatings onto each of the substrates B) is reduced. In the following, the distribution of the electric field around the periphery of the substrates B made uniform by grounding the ground members 307 will be described using FIG. 6 to FIG. 9.

FIG. 6 and FIG. 7 are model views showing the distribution of the electric field when four substrates B are arranged inside the vacuum container 301. FIG. 6 shows when the ground member 307 is arranged and FIG. 7 shows when the ground member 307 is arranged at the center of the four substrates B. The strength of the electric field is shown in FIG. 6 and FIG. 7 as well as in FIG. 8, FIG. 9 and FIG. 13 (described later) using pattern images described in each region. In other words, white regions show areas where the strength of the electric field is equal to or less than a fixed value and the strength of the electric field gradually grows stronger in regions in the following order; regions described by dots on a white background, regions described by lines slanted towards the left (right in the figure) facing downward in the figure, regions described by lines slanted towards the left (right in the figure) facing upward in the figure, regions described by horizontal lines, regions described by vertical lines, and regions described by dots on a black background.

FIG. 6 shows the distribution of the electric field around the periphery of the substrates B when only four substrates B are arranged inside the vacuum container 301. Namely, the strength of the electric field inside the vacuum container 301 is the strongest close to the side of the vacuum container 301 at each of the substrates B and gradually becomes weaker towards the vacuum container 301 from there. In contrast, the electric field at other substrates B opposite to each of the substrates B is equal to or less than a fixed value. This causes mutual interference between the other substrates B. When the electric field around the periphery of the substrates B is as shown in FIG. 6, the plasma around the periphery of each of the substrates B will not be made uniform. Consequently, unevenness when depositing coatings onto each of the substrates B is the result.

In contrast to this, FIG. 7 shows the distribution of the electric field around the periphery of the substrates B when the ground member 307 is arranged at the center of the four substrates B. Namely, the strength of the electric field inside the vacuum container 301 is the strongest close to the ground member 307 at the substrates B and is comparatively strong close to areas other than the side of the ground member 307 at each of the substrates B when the ground member 307 is not provided. In other words, the strength of the electric field around the periphery of each of the substrates B becomes stronger extending over the entire range. When the electric field around the periphery of the substrates B is as shown in FIG. 7, the plasma around the periphery of each of the substrates B will be made uniform. Consequently, unevenness when depositing coatings onto each of the substrates B (unevenness in the coating thickness of the protective surface layer) is reduced.

FIG. 8 and FIG. 9 are model views showing the distribution of the electric field when one substrate B is arranged inside the vacuum container 301. FIG. 8 shows when the ground member 307 is arranged and FIG. 9 shows when four ground members 307 are arranged at the periphery (top/bottom and left/right) of the one substrate B. The display of the strength of the electric field and the shape of the vacuum container 301 in FIG. 8 and FIG. 9 are the same as FIG. 6 and FIG. 7.

FIG. 8 shows the distribution of the electric field around the periphery of the substrate B when only one substrate B is arranged inside the vacuum container 301. Namely, the strength of the electric field inside the vacuum container 301 is the strongest close to the substrate B and gradually becomes weaker towards the vacuum container 301 from there. When the electric field around the periphery of the substrate B is as shown in FIG. 8, the plasma around the periphery of each of the substrates B will be made uniform. The distance between the vacuum container 301 is large thereby making the strength of the electric field weak. This results in the ions within the plasma not being sufficiently attracted to the substrate B.

In contrast to this, when four ground members 307 are arranged at the periphery (top/bottom and left/right) of the one substrate B, the distribution of the electric field around the periphery of the substrate B will be as shown in FIG. 9. In other words, the area where the strength of the electric field inside the vacuum container 301 is the strongest is close to the substrate B identical to that shown in FIG. 8. However, that electric field strength becomes stronger compared to when the ground members 307 are not provided. When the electric field around the periphery of the substrates B is as shown in FIG. 9, the plasma around the periphery of each of the substrates B will be made uniform, the strength of the electric field around the periphery of the substrates B will become stronger and the ions within the plasma are appropriately attracted to the substrate B at the same time.

FIG. 10 shows an example of results obtained when depositing a coating onto a substrate by the method for deposition related to the first embodiment. FIG. 10 mainly shows results obtained taken from whether or not the ground members 307 were provided inside the vacuum container 301. In addition, FIG. 10 also shows results obtained by comparing the adhesiveness after 1,000 prints and the resolution in prints in the initial state in an image forming unit.

As shown in this figure, when the ground members 307 were not provided inside the vacuum container 301, unevenness when depositing coatings within the substrates B as well as unevenness when depositing coatings between the substrates B was detected and the adhesiveness between the protective surface layer and the carrier transport layer worsened after 1,000 prints. Because of this, there is a possibility that scrapes on the protective surface layer due to scratches while printing and shortened lifespan of the photosensitive material itself might occur.

Moreover, unevenness when depositing coatings within the substrates B as well as unevenness when depositing coatings between the substrates B was also detected in the resolution in prints in the initial state with a possibility that the resolution of images in prints in the initial state might degrade.

In contrast, unevenness when depositing coatings within the substrates B as well as unevenness when depositing coatings between the substrates B was not detected when the ground member 307 was provided inside the vacuum container 301 and worsening of the adhesiveness between the carrier transport layer and the first protective surface layer after 1,000 prints was avoided. Because of this, scrapes on the protective surface layer due to scratches while printing and shortened lifespan of the photosensitive material itself can be reliably avoided.

In addition, unevenness when depositing coatings within the substrates B as well as unevenness when depositing coatings between the substrates B was not detected in the resolution in prints in the initial state and degradation in the resolution of images in prints in the initial state can be reliably avoided.

According to the method for deposition onto a substrate related to the first embodiment, by grounding the plurality of ground members 307 arranged at positions opposite to the deposition surface of each substrate B inside the vacuum container 301 in this manner, the electric field around the periphery of the substrates B is made uniform and the state of the plasma around the periphery of the substrates B is also made uniform in response to this. Consequently, unevenness when depositing coatings onto each of the substrates can be reduced when depositing coatings onto a plurality of substrates B and unevenness in the coating thickness of the protective surface layers of each photosensitive material 101 can also be reduced when forming protective surface layers on a plurality of photosensitive materials 101.

Second Embodiment

FIG. 11 is an outline of an example of a CVD deposition apparatus used when implementing the method for deposition onto a substrate related to the second embodiment of the present invention. FIG. 12 shows a view from above the inside of the vacuum container of the CVD deposition apparatus shown in FIG. 11.

The CVD deposition apparatus 1100 shown in FIG. 11 differs from the CVD deposition apparatus 300 shown in FIG. 3 by the fact that ground members 1101 are enclosed at the inside of the substrates B. According to the CVD deposition apparatus 1100 related to the second embodiment, the space required for the ground members 307 which require independent space can be reduced compared to the CVD deposition apparatus 300 related to the first embodiment. Therefore, this CVD deposition apparatus 1100 is suitable when manufacturing a greater quantity of photosensitive material.

As shown in FIG. 12, the ground members 1101 have a hollow cylindrical shape. The substrates B are also enclosed at the inside of the ground members. The ground members 1101 are established to have a length slightly longer facing upwards than the upper edge of the substrates B which are held in the substrate holders 302. Enclosing the substrates B at the inside results in the ground members 1101 being arranged adjacent to the substrates B inside the vacuum container 301.

The processing when forming the protective surface layer in this type of CVD deposition apparatus 1100 is identical to the processing in the CVD deposition apparatus 300 related to the first embodiment. Furthermore, the ground members 1101 are also grounded in like manner when forming the protective surface layer. Because of this, the distribution of the electric field around the periphery of the substrates B is made uniform and the state of the plasma around the periphery of each of the substrates B is also made uniform. As a result, unevenness in the coating thickness of the protective surface layer (unevenness when depositing coatings onto each of the substrates B) is reduced.

FIG. 13 is a model view showing the distribution of the electric field when one substrate B is arranged inside the vacuum container and the substrate B is enclosed in the ground member 1101. Because the distribution of the electric field when the substrate B is not enclosed in the ground member 1101 is identical to the distribution of the electric field shown in FIG. 8, the explanation is omitted. Further, the display of the strength of the electric field and the shape of the vacuum container 301 in FIG. 13 are the same as FIG. 6 and FIG. 7.

FIG. 13 shows the distribution of the electric field when the substrate B is enclosed in the ground member 1101. In other words, the area where the strength of the electric field inside the vacuum container 301 is the strongest is close to the substrate B identical to that shown in FIG. 8. However, that electric field strength becomes stronger compared to when the ground members 1101 are not provided. When the electric field around the periphery of the substrate B is as shown in FIG. 13, the plasma around the periphery of each of the substrates B will be made uniform, the strength of the electric field around the periphery of the substrates B will become stronger and the ions within the plasma are appropriately attracted to the substrate B at the same time.

Results identical to the results described in FIG. 10 can be obtained when depositing coatings by the method for deposition onto a substrate related to the second embodiment. Namely, scrapes on the protective surface layer due to scratches while printing and shortened lifespan of the photosensitive material itself can be reliably avoided and degradation in the resolution of images in prints in the initial state can also be reliably avoided.

According to the method for deposition onto a substrate related to the second embodiment, by grounding the plurality of ground members 1101 arranged at positions opposite to the deposition surface of each substrate B inside the vacuum container 301 in this manner, the electric field around the periphery of the substrates B is made uniform and the state of the plasma around the periphery of the substrates B is also made uniform in response to this. Consequently, unevenness when depositing coatings onto each of the substrates can be reduced when depositing coatings onto the plurality of substrates B and unevenness in the coating thickness of the protective surface layers of each photosensitive material 101 can also be reduced when forming protective surface layers on the plurality of photosensitive materials 101.

In particular, because each of the substrates B are enclosed inside each of the hollow cylindrical ground members 1101, the electric field around the periphery of the substrates B can effectively be made uniform compared to when the ground members 1101 are provided externally.

It is also preferable for the ground members 1101 in the CVD deposition apparatus 1100 related to the second embodiment to be embodied by a mesh pattern on the peripheral surface. When the peripheral surface of the ground members 1101 is a mesh pattern, it is possible to easily exchange CVD gas at the inside of the ground members 1101 thereby making it possible to make the state of the plasma around the periphery of each of the substrates B even more uniform.

Third Embodiment

The method for deposition onto a substrate related to the third embodiment differs from the method for deposition onto a substrate related to the second embodiment by the fact that the gas pressure while plasma generates in proportion to the distance between the substrates B and the ground members 1101 as well as the high-frequency output to the substrates B in the CVD deposition apparatus 1100 related to the second embodiment are both controlled. By controlling the gas pressure while plasma generates in proportion to the distance between the substrates B and the ground members 1101 in this manner makes it possible to optimize the state of the plasma around the periphery of the substrates B and to also optimize the deposition of coatings onto the substrates B.

FIG. 14 shows an example of a Paschen curve utilized when the method for deposition onto a substrate related to the third embodiment controls the gas pressure while plasma generates in proportion to the distance (hereinafter referred to as distance between the substrates and the ground members) between the substrates B and the ground members 1101. The Paschen curve shown in this figure uses a value that multiplies the distance between the substrates B and the ground members 1101 (Pa·mm) and a discharge start voltage (V) to represent a discharge state. The Paschen curve shown in this figure shows a case when Argon gas is being used. The as pressure and the value that multiplies the distance between the substrates and the ground members (hereinafter referred to as simply “multiplication value”) is from 1 to 100,000 Pa·mm and the discharge start voltage shows a portion from 10 to 1,000 V.

As shown in FIG. 14, the Paschen curve shows that the discharge start voltage is the smallest between a multiplication value of 500 to 1,000 Pa·mm and a voltage value of approximately 70 V to 80 V. The discharge start voltage suddenly rises in the region where the multiplication value is smaller than 500 Pa·mm. The discharge start voltage becomes 1,000 V when the multiplication value is 70 Pa·mm. In contrast, the discharge start voltage gradually rises in the region where the multiplication value is larger than 1,000 Pa·mm. The discharge start voltage becomes 1,000 V when the multiplication value is 80,000 Pa·mm.

The method for deposition onto a substrate related to the third embodiment based on this type of Paschen curve controls the gas pressure while plasma generates. In particular, a multiplication value in a fixed region of 500 Pa·mm or more is utilized as a target value in the method for deposition onto a substrate related to the third embodiment from the viewpoint of forming optimum values for the multiplication value and the discharge start voltage during the process to deposit coatings onto a substrate. Here, although a multiplication value in a region of 500 Pa·mm or more is utilized as a target value, other regions can also be utilized.

FIG. 15 shows a fixed region of a Paschen curve utilized when controlling the gas pressure while plasma generates in the method for deposition onto a substrate related to the third embodiment. In this figure, the multiplication value is principally set from 0 to 3,000 Pa·mm and the figure shows the portion of the discharge start voltage that corresponds to this range (60 V to 110 V). Furthermore, the portion of the multiplication value at 0 to 500 Pa·mm is omitted in this figure.

As shown in this figure, the discharge start voltage becomes larger in proportion to the magnitude of the multiplication value at the portion where the multiplication value is 0 to 3,000 Pa·mm. In more specific terms, the figure shows an approximate value of 70 V for the discharge start voltage when the multiplication value is 500 Pa·mm. The discharge start voltage also becomes larger as the multiplication value becomes larger. The figure shows an approximate value of 100 V for the discharge start voltage when the multiplication value is 3,000 Pa·mm.

FIG. 16 shows a more specific example of multiplication values (Pa·mm) in the method for deposition onto a substrate related to the third embodiment. In this figure the substrate B has a diameter of 30 mm. The “cylinder diameter” (mm) is the diameter of the ground member 1101 and “d” (mm) is the distance (distance between the substrates and the ground members) between the outer peripheral surface of the substrate B and the inner peripheral surface of the ground member 1101. For example, if the diameter of the ground member 1101 is 40 mm, the distance between the substrates and the ground members d will be 5 mm and if the diameter of the ground member 1101 is 800 mm, the distance between the substrates and the ground members d will be 385 mm.

As shown in this figure, if the substrate B is enclosed in the 40 mm ground member 1101 and the gas pressure is 0.5 Pa, the multiplication value will be 2.5 Pa·mm and if the gas pressure is 100 Pa, the multiplication value will be 500 Pa·mm. In the same manner, if the substrate B is enclosed in the 120 mm ground member 1101 and the gas pressure is 0.5 Pa, the multiplication value will be 22.5 Pa·mm and if the gas pressure is 100 Pa, the multiplication value will be 4,500 Pa·mm.

The gas pressure while plasma generates in proportion to the distance between the substrates and the ground members as well as the high-frequency output to the substrates B is controlled in the CVD deposition apparatus 1100 related to this embodiment. In the following, FIGS. 17 and 18 will be used to describe the effects obtained by controlling gas pressure while plasma generates as well as the high-frequency output to the substrates B.

FIG. 17 shows effects obtained when adjusting the gas pressure (Pa) supplied to the vacuum container 301 while plasma generates. In FIG. 17 the high-frequency output applied to the substrates B is fixed at 300 W.

In particular, FIG. 17 (a) shows the effects obtained by comparing the adhesiveness after 1,000 prints using photosensitive material manufactured using this substrate B. FIG. 17 (b) shows the effects obtained by comparing the resolution in prints in the initial state with this photosensitive material. FIGS. 18 (a) and (b) show the same.

As shown in FIG. 17, the adhesiveness in the protective surface layer after 1,000 prints changes its properties in proportion to the multiplication value. In more specific terms, when the distance between the substrates and the ground members is 10 mm, degraded properties are exhibited when the gas pressure is from 5 to 10 Pa and favorable properties are exhibited when the gas pressure is from 50 to 100 Pa. Furthermore, when the distance between the substrates and the ground members is 25 mm, degraded properties are exhibited when the gas pressure is 5 Pa and favorable properties are exhibited when the gas pressure is 100 Pa. Optimum properties are exhibited when the gas pressure is 50 Pa. Even further, when the distance between the substrates and the ground members is 85 mm, favorable properties are exhibited when the gas pressure is 5 Pa or 10 Pa to 50 Pa and optimum properties are exhibited when the gas pressure is 25 Pa. Because of this, it is understood that optimum properties are exhibited when the multiplication value is within approximately 2,000 to 2,500 Pa·mm (refer to FIG. 16).

In contrast, properties of the resolution in prints in the initial state change in proportion to the multiplication value. In more specific terms, when the distance between the substrates and the ground members is 10 mm, favorable properties are exhibited when the gas pressure is from 5 to 25 Pa and degraded properties are exhibited when the gas pressure is from 50 to 100 Pa. Even further, when the distance between the substrates and the ground members is 25 mm, favorable properties are exhibited when the gas pressure is 5 Pa or 10 Pa to 100 Pa and degraded properties are exhibited when the gas pressure is from 25 to 50 Pa. When the distance between the substrates and the ground members is 45 mm, favorable properties are exhibited when the gas pressure is 5 Pa or 50 Pa or 100 Pa and degraded properties are exhibited when the gas pressure is from 10 to 25 Pa. Moreover, when the distance between the substrates and the ground members is 85 mm, degraded properties are exhibited when the gas pressure is from 5 to 10 Pa and favorable properties are exhibited when the gas pressure is from 25 to 100 Pa. Because of this, it is understood that favorable properties are exhibited when the multiplication value is within approximately 25 to 250 Pa·mm as well as approximately 2,125 to 8,500 Pa·mm (refer to FIG. 16).

In the CVD deposition apparatus 1100 related to the third embodiment the gas pressure is controlled in proportion to the distance between the substrates and the ground members corresponding to the diagonal lines shown in FIG. 17 taking into consideration these types of properties. According to the method for deposition onto a substrate of the third embodiment, controlling the gas pressure while plasma generates in proportion to the distance between the substrates B and the ground members 1101 in this manner makes it possible to optimize the state of the plasma around the periphery of the substrates B and to also optimize the deposition of coatings onto the substrates B.

In particular, because settings are made to increase the gas pressure of the generating plasma as the distance between the substrates B and the ground members 1101 becomes shorter in the CVD deposition apparatus 1100 related to the third embodiment, it is possible to optimize the state of the plasma around the periphery of the substrates B and to also optimize the deposition of coatings onto the substrates.

FIG. 18 shows effects obtained when adjusting the high-frequency output (W) to the substrate B while plasma generates. In FIG. 18 the gas pressure supplied to the vacuum container 301 is fixed at 25 Pa.

As shown in FIG. 18, the adhesiveness in the protective surface layer after 1,000 prints changes its properties in proportion to the multiplication value. In more specific terms, when the distance between the substrates and the ground members is 10 mm, degraded properties are exhibited when the high-frequency output is 100 W or 250 W to 500 W and optimum properties are exhibited when the high-frequency output is 200 W. Further, when the distance between the substrates and the ground members is 25 mm, degraded properties are exhibited when the high-frequency output is 100 W and favorable properties are exhibited when the high-frequency output is 200 W or 300 to 500 W. Optimum properties are exhibited when the high-frequency output is 250 W. Even further, when the distance between the substrates and the ground members is 45 mm, degraded properties are exhibited when the high-frequency output is 100 W and favorable properties are exhibited when the high-frequency output is 200 W or 300 to 500 W. Optimum properties are exhibited when the high-frequency output is 250 W. Moreover, when the distance between the substrates and the ground members is 85 mm, degraded properties are exhibited when the high-frequency output is from 100 W to 200 W and favorable properties are exhibited when the high-frequency output is 250 W or 500 W. Optimum properties are exhibited when the high-frequency output is 300 W. Because of this, it is understood that the adhesiveness in the protective surface layer exhibits optimum properties when the high-frequency output is increased following increases in the multiplication value.

In contrast, properties of the resolution in prints in the initial state change in proportion to the multiplication value. In more specific terms, when the distance between the substrates and the ground members is 10 mm, favorable properties are exhibited when the high-frequency output is from 100 to 250 W and degraded properties are exhibited when the high-frequency output is from 300 to 500 W. Even further, when the distance between the substrates and the ground members is 25 mm, favorable properties are exhibited when the high-frequency output is from 100 to 300 W and degraded properties are exhibited when the high-frequency output is 500 W. When the distance between the substrates and the ground members is 45 mm, favorable properties are exhibited when the high-frequency output is from 100 to 300 W and degraded properties are exhibited when the high-frequency output is 500 W. Moreover, when the distance between the substrates and the ground members is 85 mm, favorable properties are exhibited when the high-frequency output is in a range of 100 to 500 W. Because of this, it is understood that the resolution exhibits degraded properties when the multiplication values are values in a fixed range.

In the CVD deposition apparatus 1100 related to this embodiment the high-frequency output is controlled in proportion to the distance between the substrates and the ground members corresponding to the diagonal lines shown in FIG. 18 taking into consideration these types of properties. According to the method for deposition onto a substrate of the third embodiment, controlling the high-frequency output applied to the substrates B in proportion to the distance between the substrates B and the ground members 1101 in this manner makes it possible to optimize the state of the plasma around the periphery of the substrates B and to also optimize the deposition of coatings onto the substrates B.

In particular, because settings are made to reduce the high-frequency output applied to the substrates B as the distance between the substrates B and the ground members 1101 becomes shorter in the CVD deposition apparatus 1100 related to the third embodiment, it is possible to optimize the state of the plasma around the periphery of the substrates B and to also optimize the deposition of coatings onto the substrates.

Although controlling the gas pressure in the CVD deposition apparatus 1100 related to the second embodiment was described in the method for deposition onto a substrate related to the third embodiment, there is no limitation to this and the gas pressure can also be controlled in the CVD deposition apparatus 300 related to the first embodiment. For this case as well, the same effects can be obtained as the method for deposition onto a substrate related to the third embodiment.

Substrates B (rollers used for the photosensitive material 101) used in the photosensitive material 101 of an image forming unit were described above. This description, however, is not limited to substrates B but can also be applied to other uses. For example, if there is a substrate B that requires some sort of protective coating, this description can be applied to the substrate B as well.

It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular structures, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.

The present invention is not limited to the above described embodiments, and various variations and modifications may be possible without departing from the scope of the present invention.

This application is based on the Japanese Patent Application No. 2004-288356 filed on Sep. 30, 2004, entire content of which is expressly incorporated by reference herein.

Claims

1. A method for depositing a layer on a substrate using a grounded vacuum container, the vacuum container containing a plurality of substrates, a photo conductor being formed on each of the plurality of substrates, the method comprising:

arranging a plurality of ground members around each of the plurality of substrates in the vacuum container;

filling the vacuum container with a CVD (Chemical Vapor Deposition) gas;

applying a voltage to the plurality of substrates to generate plasma around the plurality of substrates, ions being generated by collisions between the CVD gas and the generated plasma; and

attracting the generated ions to the plurality of substrates to deposit a layer on each of the plurality of substrates.

2. The method according to claim 1, wherein the voltage applied to the plurality of substrates comprises a high-frequency voltage.

3. The method according to claim 1, wherein the voltage applied to the plurality of substrates comprises a high-frequency voltage combined with a negative voltage.

4. The method according to claim 3, wherein the high-frequency voltage and the negative voltage comprise pulse voltages.

5. The method according to claim 1, wherein the ground member comprises a cylindrical member, and each of the plurality of the cylindrical members is arranged around each of the plurality of substrates.

6. The method according to claim 1, wherein the ground member comprises a hollow cylindrical member, and each of the plurality of substrates is contained in each of the plurality of the hollow cylindrical members.

7. The method according to claim 6, wherein a surface of the ground member comprises a mesh.

8. The method according to claim 1, a distance between the periphery of the vacuum container and a substrate closest to the periphery of the vacuum container is D1, and a distance between a substrate and a closest ground member is D2, D1 being larger than D2.

9. The method according to claim 1, a length of the ground member is L1, and a length of the substrate is L2, L1 being larger than L2.

10. A method for producing a photo conductor using a grounded vacuum container, the vacuum container containing a plurality of substrates, a photo conductor being formed on each of the plurality of substrates, the method comprising:

arranging a plurality of ground members around each of the plurality of substrates in the vacuum container;

filling the vacuum container with a CVD (Chemical Vapor Deposition) gas;

applying a voltage to the plurality of substrates to generate plasma around the plurality of substrates, ions being generated by collisions between the CVD gas and the generated plasma; and

attracting the generated ions to the plurality of substrates to deposit a layer on each of the plurality of substrates.

11. The method according to claim 10, wherein the voltage applied to the plurality of substrates comprises a high-frequency voltage.

12. The method according to claim 10, wherein the voltage applied to the plurality of substrates comprises a high-frequency voltage combined with a negative voltage.

13. The method according to claim 12, wherein the high-frequency voltage and the negative voltage comprise pulse voltages.

14. The method according to claim 10, wherein the ground member comprises a cylindrical member, and each of the plurality of the cylindrical members are arranged around each of the plurality of substrates.

15. The method according to claim 10, wherein the ground member comprises a hollow cylindrical member, and each of the plurality of substrates is contained in each of the plurality of the hollow cylindrical members.

16. The method according to claim 15, wherein a surface of the ground member comprises a mesh.

17. The method according to claim 10, a distance between the periphery of the vacuum container and a substrate closest to the periphery of the vacuum container is D1, and a distance between a substrate and a closest ground member is D2, D1 being larger than D2.

18. The method according to claim 10, a length of the ground member is L1, and a length of the substrate is L2, L1 being larger than L2.

19. The method according to claim 10, wherein the layer deposited on the substrate comprises a layer of hydrocarbon gas-based amorphous carbon.

20. A method for depositing a layer on a substrate using a grounded vacuum container, the vacuum container containing a plurality of substrates, a photo conductor being formed on each of the plurality of substrates, the method comprising:

arranging a plurality of ground members around each of the plurality of substrates in the vacuum container;

filling the vacuum container with a CVD (Chemical Vapor Deposition) gas;

controlling gas pressure of the CVD gas, based on a distance between the substrate and the ground member;

applying a voltage to the plurality of substrates to generate plasma around the plurality of substrates, ions being generated by collisions between the CVD gas and the generated plasma; and

attracting the generated ions to the plurality of substrates to deposit a layer on each of the plurality of substrates.

21. The method according to claim 20, wherein the shorter the distance between the substrate and the ground member, the higher the gas pressure.

22. A method for depositing a layer on a substrate using a grounded vacuum container, the vacuum container containing a plurality of substrates, a photo conductor being formed on each of the plurality of substrates, the method comprising:

arranging a plurality of ground members around each of the plurality of substrates in the vacuum container;

filling the vacuum container with a CVD (Chemical Vapor Deposition) gas;

controlling a voltage applied to the plurality of substrates, based on a distance between the substrate and the ground member;

applying a voltage to the plurality of substrates to generate plasma around the plurality of substrates, ions being generated by collisions between the CVD gas and the generated plasma; and

attracting the generated ions to the plurality of substrates to deposit a layer on each of the plurality of substrates.

23. The method according to claim 22, wherein the shorter the distance between the substrate and the ground member, the lower the voltage.

24. The method according to claim 22, wherein the voltage applied to the plurality of substrates comprises a high-frequency voltage.

25. The method according to claim 22, wherein the voltage applied to the plurality of substrates comprises a high-frequency voltage combined with a negative voltage.

26. The method according to claim 25, wherein the high-frequency voltage and the negative voltage comprise pulse voltages.

27. The method according to claim 22, wherein the substrate comprises a metallic tub in a cylindrical shape.

28. The method according to claim 27, wherein the metallic tub comprises a core tube utilized for a photo conductor.

29. The method according to claim 22, wherein the ground member comprises a cylindrical member, and each of the plurality of the cylindrical members are arranged around each of the plurality of substrates.

30. The method according to claim 22, wherein the ground member comprises a hollow cylindrical member, and each of the plurality of substrates is contained in each of the plurality of the hollow cylindrical members.

31. The method according to claim 22, wherein the layer deposited on the substrate comprises a layer of hydrocarbon gas-based amorphous carbon.

32. The method according to claim 31, wherein the layer of hydrocarbon gas-based amorphous carbon comprises a protective surface layer of a photo conductor.