JPH11258904A - Developing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roll by which the resolution of an image by an image forming device is excellently maintained. SOLUTION: As for the developing roll developing a latent image formed on the outer peripheral surface of a photoreceptor by being brought into contact with the photoreceptor and supplying the outer peripheral surface of the photoreceptor with toner, it is provided with a core bar 12 and a roll main body 16 made of conductive rubber stuck to the outer periphery of the core bar 12 through a primer 14, and is used for the image forming device in a state where the outer periphery of the roll main body 16 is exposed, and the glossiness of the outer peripheral surface of the roll main body 16 is set within the range of >=1.3 and <=3.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a developing roll provided in a developing device used as a process device in an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as an apparatus used as a process device in an image forming apparatus such as an electronic copying apparatus or a laser printer, a toner is supplied onto a photosensitive drum to form an electrostatic latent image formed on the photosensitive drum. 2. Description of the Related Art A developing device for developing (developing an image) is known. 2. Description of the Related Art In recent years, in an image forming apparatus using a non-magnetic one-component toner as a toner, a developing roll formed of a conductive roll may be used as a component for transporting the toner in a developing device.

[0003] As this developing roll, a configuration in which a conductive rubber roll main body is disposed around the outer periphery of a metal core material is known. Is charged and adsorbed, and the toner is conveyed onto the outer peripheral surface of the photosensitive drum according to the rotation of the developing roll via fine irregularities on the surface of the outer peripheral surface of the developing roll.

For this reason, conventionally, as a factor affecting the quality of an image formed by an image forming apparatus, particularly the resolution, attention has been paid to the surface roughness (including so-called "undulation") of a developing roll. The theme of quality control is how the surface roughness can be kept constant, in other words, the developing rolls whose surface roughness is determined not to be within the predetermined range are discarded as defective. , Quality control was done.

[0005]

In order to inspect the surface roughness of the developing roll as described above, the inspection needle must be brought into contact with the outer peripheral surface of the developing roll according to the JIS standard. Even if it is judged as “good”, there is a possibility that the outer peripheral surface of the developing roll may be damaged by this inspection. You have to do it.

[0006] Such a surface roughness test is very time-consuming. Specifically, the moving speed of the test needle is set to, for example, 0.3 mm / sec, and φ16 mm
When the outer peripheral surface of the developing roll is inspected over the entire circumference, the measured length is about 50.24 mm, and this inspection alone takes about 3 minutes. In this way, from the viewpoint of productivity, it is a fact that 100% inspection is impossible,
Improvement is required.

On the other hand, in order to prevent the manufactured developing roll from being damaged by inspection, the developing roll is incorporated into an image forming apparatus without performing a surface roughness test, and the image forming process is actually executed to form, for example, on a sheet. A test (so-called image output test) for forming a “solid black” image and determining the density unevenness has been performed. However, in this image output test, if deterioration of image quality due to a defect of the developing roll is confirmed, remove the defective developing roll,
A new developing roll must be mounted, but even in such a case, an image output test must be performed again, which has been pointed out to be very inefficient, and improvement is demanded.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a developing roll in which the resolution of an image formed by an image forming apparatus is well maintained. is there.

A further object of the present invention is to determine whether the surface condition of the developing roll, which affects the resolution of an image formed by the image forming apparatus, is good or bad without incorporating the developing roll into the image forming apparatus. An object of the present invention is to provide a developing roll that can be distinguished.

Another object of the present invention is to provide a developing roll capable of quantitatively measuring the surface condition of the developing roll which affects the resolution of an image formed by an image forming apparatus.

Another object of the present invention is to provide a developing roll which enables inspection of the surface state of the developing roll which affects the resolution of an image formed by an image forming apparatus in a non-contact state. .

[0012]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, the developing roll according to the present invention comprises:
According to the first aspect of the present invention, there is provided a developing roll for contacting a photosensitive member, supplying toner to an outer peripheral surface of the photosensitive member, and visualizing a latent image formed on the outer peripheral surface of the photosensitive member. With gold
A rubber layer formed on the outer periphery of the metal core, and used in an image forming apparatus in a state where the outer periphery of the rubber layer is exposed, and the outer peripheral surface of the rubber layer has a glossiness of 1.3 or more and 3.5 or more. It is characterized in the following range.

According to a second aspect of the present invention, there is provided a developing roller, wherein the glossiness of the outer peripheral surface of the rubber layer is in the range of 1.5 or more and 3.0 or less. .

According to a third aspect of the present invention, in the developing roll according to the present invention, the outer peripheral surface of the rubber layer is polished with a film.

According to a fourth aspect of the present invention, in the developing roller, the rubber layer is formed of conductive silicone rubber.

According to a fifth aspect of the present invention, in the developing roll according to the fifth aspect, the rubber layer is bonded to the outer periphery of the metal core via a primer.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of the developing roll according to the present invention will be described below in detail.

{Description of Developing Roll 10} First, the structure of the developing roll 10 which characterizes this embodiment will be described. For example, in an image forming apparatus such as an electronic copying machine, a laser beam printer, or an electronic facsimile machine, the developing roll 10 is a photosensitive member (specifically,
A developer (in this embodiment, a non-magnetic one-component toner) is supplied (conveyed) to the outer peripheral surface of the photosensitive drum, and the electrostatic latent image formed on the outer peripheral surface of the photoconductor is visualized ( That is, in the developing device for developing, the toner supply (conveyance)
It is provided as a member. As shown in FIG. 1, the developing roll 10 includes a metal core 12 and a conductive rubber roll body 16 attached to the outer periphery of the metal core 12 via a primer 14. I have.

Here, the cored bar 12 may be a metal having a predetermined rigidity and a sufficient conductivity, and in this embodiment, is made of an iron material. Further, in this embodiment, the roll body 16 is formed to have a size capable of forming an image on an A4 size sheet, and its outer diameter is set to φ18 mm. Further, in this embodiment, the roll body 16 is formed of conductive silicone rubber.

The developing roll 10 has a roll resistance value of 10 [4] Ω (in the following description, the number in [] represents a power of 10; 4] indicates 10 to the fourth power.) To 1
It is set within the range of 0 [7] Ω.

In this embodiment, eight developing rolls 10 are prepared, and these eight developing rolls 10 are used.
Experiments were performed on gloss and image resolution. Hereinafter, the configuration of the developing roll 10 according to each embodiment will be specifically described.

Example 1 A primer 14 was applied to the outer peripheral surface of an iron core 12 having an outer diameter of 17 mm, and a conductive silicone rubber (XE23-B5435; manufactured by Toshiba Silicone Co., Ltd.) was extruded through the primer 14. Then, a roll body 16 made of conductive rubber is provided on the outer periphery of the cored bar 12. Thus, the material of the developing roll 10 is formed. Then, this material is subjected to a primary vulcanization treatment in a steam pot, and then to a secondary vulcanization treatment in an oven.
Developing roll 10 to which a roll body 16 is attached via
To form a base material.

Then, the base material is made of φ18.5 mm-1.
Coarsely ground to an outer diameter of 8.6 mm.
Finish grinding was performed as a final step using a cylindrical grinder (LEO-600 F2; manufactured by Mizuguchi Seisakusho), and the developing roll 10 was finally obtained. In the following description, it is indicated as the roll number of the developing roll 10 obtained in the first embodiment.

Embodiments 2 to 8 The same forming steps as in Embodiment 1 described above
Along with the processing step, the developing roll 10 is obtained through the above-described finish grinding processing, and the outer peripheral surface of the roll body 16 as the outermost peripheral surface of the developing roll 10 is subjected to a film polishing treatment as a final step, so that the developing roll 10 Finally got.
In the following description, it is referred to as the roll number of the developing roll 10 obtained in Example 2, and the same applies hereinafter.

Next, the correlation between the glossiness of the developing roll and the resolution of the image, which is the gist of the present invention, will be described in detail.

{Description of Correlation between Glossiness and Image Resolution} (Explanation of Measurement of Development Roll Glossiness) First, measurement conditions of the development roll glossiness will be described. The glossiness measurement mechanism used was VGS-1001DP manufactured by Nippon Denshoku Industries Co., Ltd.
JIS Z874 using this gloss measurement mechanism.
The 75-degree specular gloss was measured based on Method 2 in 1. When calibrating the 95% gloss, a flat plate holder was used.

In the measurement of the glossiness, the aforementioned 8
The measurement position of the developing roll 10 is set at the center in the axial direction, and as shown in FIG.
0 is divided into four equal parts along the circumferential direction, and the measurement start position is denoted by the symbol X.
The glossiness was measured first at this X position. When the measurement of the gloss at this X position is completed,
The developing roll 10 was rotated clockwise by 90 degrees, the stop position thereof was indicated by a symbol Y, and the glossiness was measured at this Y position.

When the measurement of the glossiness at the Y position is completed, the developing roll 10 is further rotated clockwise by 90 degrees, and the stop position thereof is indicated by the symbol X '. The gloss was measured. When the measurement of the glossiness at the X 'position is completed, the developing roll 10 is further rotated clockwise by 90 degrees, the stop position thereof is indicated by a symbol Y', and the glossiness is measured at the Y 'position. did.

That is, the measured value of each developing roll 10 is composed of four measured values (X, Y, X ', Y') shifted by 90 degrees in the circumferential direction at the central portion in each axial direction. become. The average value of four measured values (X, Y, X ', Y') was adopted as the glossiness of each developing roll 10.

(Explanation of Measurement of Toner Conveying Ability of Developing Roll 10) On the other hand, an important factor for examining the resolution of an image is the conveying ability of the toner conveyed by the developing roll 10, and The transport capacity includes the thickness of the toner layer carried on the surface of the developing roll 10 (that is, the thickness of the toner layer).

Therefore, the eight developing rolls 10 whose glossiness was measured by the above-described method were sequentially mounted on the cartridge, and after passing the blank paper, the developing roll was removed from the cartridge to remove the toner adhering to the outer peripheral surface of the developing roll. The adhesion weight was measured by a measuring method known as a so-called "tape method". The tape used in this tape method is Sumitomo 3M
Mending tape (width 12 mm).

The measurement results of the glossiness and the toner layer thickness of each developing roll 10 are as shown in Table 1.

[0033]

[Table 1]

(Explanation of Correlation) As shown in FIG. 8, the correlation between the gloss of the developing roll 10 and the thickness of the toner layer based on Table 1 indicates that the gloss is in the range of 0.6 to 3.5. As a result, a strong correlation that could draw a linear calibration curve was confirmed.

That is, by measuring the glossiness of the developing roll 10 in a non-contact state, the developing roll 10 can be mounted on a cartridge without conducting a paper-passing experiment, and the contact can be measured as in a surface roughness test. Even if no test is performed, the thickness of the toner layer can be reliably predicted.

{Measurement of Surface Roughness} Next, the surface roughness of the eight developing rolls 10 was measured.

Here, the surface roughness of each developing roll 10 is as follows:
Using a surface roughness meter (Surfcom 550A: manufactured by Tokyo Seimitsu Co., Ltd.), the measurement length is 2.5 m based on the old JIS standard.
m and the moving speed of the inspection needle were measured under the measurement conditions of 0.3 mm / sec. Table 2 shows the measurement results.

[0038]

[Table 2]

As is evident from Table 2, the surface roughness of the developing roll whose outer peripheral surface is polished is smaller than that of the developing roll whose outer peripheral surface is not polished. It has been found that there is a correlation that the outer peripheral surface of the developing roll 10 has a finer surface roughness than the case where the film is not polished. However, it has not been possible to specify that there is some correlation between glossiness and surface roughness.

{Explanation on Correlation between Glossiness and Image Resolution} (Explanation on Measurement of Image Resolution) {Measurement of Line Width and Line Pitch when Reproducing Fine Line} Next, eight developing rolls 10 With 1,200 dpi as the image resolution
Are sequentially mounted on a developing unit of an image evaluator (Feather 550; manufactured by Tektronix) having the ability of
An image in which a fine line with a line pitch of 175 μm was drawn was printed (printed) on A4 size paper using cyan toner. Here, the line width and the line pitch described above are, as shown in FIG. 2, the thickness of the drawn thin line (the width along the direction orthogonal to the direction in which the thin line extends) and the width of the thin line adjacent to each other. The center-to-center distances are shown.

Then, a magnified photograph of the image output on the A4 size paper was taken at a magnification of 50 times using an optical microscope (PMG3: manufactured by Olympus Optical Industrial Co., Ltd.). First, the results (enlarged photographs) of Examples 1 to 8 are shown in FIGS. 3A to 3H, respectively. Then, on each of the photographs shown in FIGS. 3A to 3H, the line width was measured at 80 locations and the line pitch was measured at 70 locations by calipers. The measurement results for these line widths are shown in FIG.
4H show a histogram, and the measurement results regarding the line pitch are shown as histograms in FIGS. 5A to 5H for each of the eight developing rolls.

Here, in the enlarged photographs shown in FIGS. 3A to 3H, the thin lines are developed as black bands and the intervals are developed as white bands. The width was measured, and the width of the white band was measured as the interval between the thin lines.
Since the line pitch is a distance from the center line of a thin line to the center line of an adjacent thin line, it was calculated from the measured line width and interval of the thin line using the following formula. That is, line pitch = line width × (1/2) + interval + next line width × (1 /
2) In addition, as shown in FIG. 6, when a convex portion or a concave portion was present in the black band, the width from the vertex of the convex portion or the bottom of the concave portion, ie, the width from the boundary between the black portion and the white portion was measured. . Furthermore, as shown in FIG. 7, when the boundary between the black part and the white part was unclear, an extension was drawn from a clear part before and after the boundary, and the measurement was performed after assuming the boundary from this extension.

{Evaluation of Reproducibility of Fine Lines} On the other hand, in evaluating the reproducibility of thin lines, it is possible to judge that the reproducibility of fine lines is good if the measured values have no variation and are constant. Based on the measurement results shown in FIGS. 4A to 4H and FIGS. 5A to 5H, the standard deviation for each example regarding the line width and the line pitch was calculated. Table 3 and Table 4 show the calculation results.
Shown in

[0044]

[Table 3]

[0045]

[Table 4]

FIG. 8 shows the correlation between the glossiness and the line width and line pitch from Tables 3 and 4.

In evaluating the calculation results of the standard deviation shown in Table 3, when determining the reproducibility of the fine line, the optimum surface condition for improving the reproducibility of the fine line has a smoothness close to a mirror surface. Things are ideal. For this reason, it is possible to judge that the measured value is constant without variation, so that the reproducibility of the fine line is good.
Those having a standard deviation of 15 or more and less than 20 were determined to be good (○) for those having a standard deviation of less than 5 and less than 20.
Those having a standard deviation of 20 or more were judged to be unacceptable (x).

As a result, as shown in the comprehensive evaluation in Table 5 and FIG. 8, the reproducibility of a fine line is determined when the glossiness is 1.3 to 3.5 in the range of good or excellent as the judgment result. From the viewpoint, it has been found that a material having a glossiness of 1.5 to 3.0, which is in an excellent range as a result of the determination, is particularly optimum.

[0049]

[Table 5]

That is, the developing roll, which is used for low resolution by finish grinding, uses a film having a film count of 600 to 4,000 to form a conductive roll on the outermost peripheral surface of the developing roll 10 after finish grinding. Rubber roll body 1
By polishing the outer peripheral surface of the film 6 as a film, it can be used as a developing roll for high resolution, and the productivity can be improved, and thereby, the manufacturing cost of the developing roll can be reduced. Can be done.

It is needless to say that the present invention is not limited to the configuration of the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

For example, in the description of the above embodiment,
Although various numerical values and raw materials have been described, the present invention is not limited to such numerical values and raw materials, but may be anything as long as a similar effect can be achieved.

The surface conditions shown in Table 5 show the results of visual observation by the observer.

As described above, according to the present invention, there is provided a developing roll in which the resolution of an image when formed by an image forming apparatus is kept good.

Further, according to the present invention, it is possible to determine whether the surface condition of the developing roll, which affects the resolution of an image formed by the image forming apparatus, is good without incorporating the developing roll into the image forming apparatus. Is provided.

Further, according to the present invention, there is provided a developing roll capable of quantitatively measuring the surface condition of the developing roll which affects the resolution of an image formed by the image forming apparatus.

Further, according to the present invention, there is provided a developing roll capable of inspecting the surface condition of the developing roll in a non-contact state which affects the resolution of an image formed by the image forming apparatus. .

[0056]

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a developing roll according to the present invention and a side position of glossiness thereof.

FIG. 2 is a diagram illustrating a line width and a line pitch of a thin line.

FIG. 3A is a view showing an image when the fine line shown in FIG. 2 is reproduced using the developing roll of Example 1 by a photograph taken with an optical microscope.

FIG. 3B is a diagram showing an image when the fine line shown in FIG. 2 is reproduced using the developing roll of Example 2 by a photograph taken with an optical microscope.

FIG. 3C is a diagram showing an image obtained by reproducing the fine line shown in FIG. 2 using the developing roll of Example 3 by a photograph taken with an optical microscope.

FIG. 3D is a diagram showing an image when the fine line shown in FIG. 2 is reproduced using the developing roll of Example 4 by a photograph taken with an optical microscope.

FIG. 3E is a diagram showing an image obtained by reproducing the fine line shown in FIG. 2 using the developing roll of Example 5 by a photograph taken with an optical microscope.

FIG. 3F is a diagram showing an image when the fine line shown in FIG. 2 is reproduced using the developing roll of Example 6 by a photograph taken with an optical microscope.

FIG. 3G is a diagram showing an image when the fine line shown in FIG. 2 is reproduced using the developing roll of Example 7 by a photograph taken with an optical microscope.

FIG. 3H is a diagram showing an image when the fine line shown in FIG. 2 is reproduced using the developing roll of Example 8 by a photograph taken with an optical microscope.

FIG. 4A is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 1 over 80 locations.

FIG. 4B is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 2 over 80 locations.

FIG. 4C is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 3 over 80 locations.

FIG. 4D is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 4 over 80 locations.

FIG. 4E is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 5 over 80 locations.

FIG. 4F is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 6 over 80 locations.

FIG. 4G is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 7 over 80 locations.

FIG. 4H is a diagram showing, as a histogram, a measurement result obtained by measuring the line width of a thin line reproduced using the developing roll of Example 8 over 80 locations.

FIG. 5A is a diagram showing, as a histogram, measurement results obtained by measuring the line pitch of fine lines reproduced using the developing roll of Example 1 over 70 locations.

FIG. 5B is a diagram showing, as a histogram, measurement results obtained by measuring the line pitch of fine lines reproduced using the developing roll of Example 2 over 70 locations.

FIG. 5C is a diagram showing, as a histogram, a measurement result obtained by measuring the line pitch of a fine line reproduced using the developing roll of Example 3 over 70 locations.

FIG. 5D is a diagram showing, as a histogram, a measurement result obtained by measuring the line pitch of a fine line reproduced using the developing roll of Example 4 over 70 locations.

FIG. 5E is a diagram showing, as a histogram, measurement results obtained by measuring the line pitch of fine lines reproduced using the developing roll of Example 5 over 70 locations.

FIG. 5F is a diagram showing, as a histogram, a measurement result obtained by measuring the line pitch of a fine line reproduced using the developing roll of Example 6 over 70 locations.

FIG. 5G is a diagram showing, as a histogram, measurement results obtained by measuring the line pitch of fine lines reproduced using the developing roll of Example 7 over 70 locations.

FIG. 5H is a diagram showing, as a histogram, measurement results obtained by measuring the line pitch of fine lines reproduced using the developing roll of Example 8 over 70 locations.

FIG. 6 is a diagram for explaining measurement of a reproduced fine line unevenness state.

FIG. 7 is a diagram for explaining measurement of a reproduced thin line in an unclear state;

FIG. 8 is a diagram simultaneously showing a correlation between glossiness and a toner layer thickness, and a correlation between glossiness and a standard deviation of a line width and a line pitch of a fine line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Development roll 12 Core metal 14 Primer 16 Roll body

Claims (5)

[Claims] A developing roller for contacting the photosensitive member and supplying toner to an outer peripheral surface of the photosensitive member to visualize a latent image formed on the outer peripheral surface of the photosensitive member; A rubber layer formed on the outer periphery of a cored bar, used in an image forming apparatus in a state where the outer periphery of the rubber layer is exposed, wherein the gloss of the outer peripheral surface of the rubber layer is 1.3 or more and 3.5 or less A developing roll, wherein 2. The developing roll according to claim 1, wherein a glossiness of an outer peripheral surface of the rubber layer is in a range of 1.5 or more and 3.0 or less. 3. The developing roll according to claim 1, wherein an outer peripheral surface of the rubber layer is polished with a film. 4. The developing roll according to claim 1, wherein said rubber layer is formed of conductive silicone rubber. 5. The developing roll according to claim 4, wherein the rubber layer is bonded to an outer periphery of the core via a primer.