JP2000081820A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming device reduced in jitter etc., even in the case of grinding a photoreceptor drum with a grinding roller and where the grinding force is not influenced by a printing pattern and the occurrence of an insufficient grinding is prevented even in the case of continuously printing a pattern of a low printing ratio. SOLUTION: The image forming device is provided with an amorphous silicon photoreceptor, a developing means 4 for forming a toner image with abrasive toner, a supply means 4 for supplying the abrasive toner, grinding means 6 and 9 for bringing an elastic roller into press-contact with the surface of the photoreceptor and rotating the elastic roller so as to grind the surface of the photoreceptor, and the surface of the photoreceptor is ground so that the surface roughness of the photoreceptor may be <=500 Å. In this case, the grinding means 6 and 9 are provided with an grinding mode of preventing the elastic roller which is brought into press contact with the photoreceptor from being driven when a printing operation is executed, and supplying the abrasive toner by the abrasive toner supplying means 4, and also, rotating the elastic roller when the printing operation is not executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus using an amorphous silicon (hereinafter referred to as "a-Si") photosensitive drum, and particularly to an a-Si photosensitive drum capable of suppressing image deletion. It is related to the used method.

[0002]

2. Description of the Related Art It has been known that an image forming apparatus using an a-Si photosensitive drum is liable to cause image deletion due to its characteristics. That is, when charging is performed using a charger, ozone is generated by discharging the charger.
The components in the air are decomposed by this ozone, and NOx and S
An ion product such as Ox is generated. Since this ion product is water-soluble, it adheres to the photoreceptor drum and penetrates into a roughness structure of about 0.1 μm on the surface of the photoreceptor drum. In addition, they take in moisture in the atmosphere, which lowers the resistance of the surface of the photosensitive drum. As a result, a lateral flow of the potential occurs at the edge of the electrostatic latent image formed on the surface of the photosensitive drum, and as a result, the image may flow.

Conventionally, a heater is provided in a photoconductor drum to give energy for releasing the moisture taken in by the ion product, thereby suppressing a reduction in the resistance of the photoconductor drum surface in a high-humidity environment. It has been generalized.

However, in such an apparatus, the number of components for constituting the heater is large, which not only increases the cost but also requires consideration of safety.
Therefore, prior to the filing of the present application, the present applicant has developed a system for polishing ozone by using a system in which a photoreceptor is polished by an interaction between a polishing toner mixed with a polishing agent and a polishing means (a polishing roller and a cleaning blade) without using a heater. A technique for removing an object was proposed (Japanese Patent Application No. 9-315984).

This technique is an image forming apparatus having a structure for polishing the surface roughness of an a-Si photosensitive drum so as to be less than Rz 500 ° (angstrom). Even if the substance adheres to the surface of the photosensitive drum, the ozone product can be sufficiently removed to polish the surface roughness to Rz 500 ° or less.

[0006]

However, in order to polish the photosensitive drum with the elastic roller, a large pressing force of the elastic roller against the photosensitive drum and a linear velocity difference of about 20% are required. Image defects occur due to uneven rotation of the elastic roller. Further, when a pattern having a low printing ratio is continuously printed because the polishing force is easily affected by the printing pattern, an image flow occurs due to insufficient polishing. The present invention has been made in view of the above-described problems, and reduces jitter and the like even when the photosensitive drum is polished by a polishing roller. An object of the present invention is to provide an image forming apparatus that does not cause insufficient polishing even when printing.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an electrostatic latent image carrier using an amorphous silicon photoreceptor, and a toner comprising a polishing toner containing an abrasive in the electrostatic latent image. Developing means for forming an image, supply means for supplying the polishing toner, and polishing means for pressing an elastic roller against the surface of the photoconductor and rotating the elastic roller to polish the surface of the photoconductor. An image forming apparatus comprising: an image forming apparatus configured to print the toner image on paper while polishing the surface roughness of the photoreceptor to 500 ° or less by an interaction between the polishing toner supplied by the supply unit and the polishing unit. When the non-printing is performed, the polishing toner supply unit supplies the polishing toner, and polishes the photoconductor surface so that the elastic roller has a peripheral speed difference with respect to the rotation of the photoconductor. Wherein by preventing driving of the elastic roller which is pressed against the photosensitive member, in that the elastic roller is configured to perform a driven rotation that rotates with the rotation of the photosensitive member to.

In other words, a mode different from the normal printing operation is provided during non-printing, and the elastic roller is driven to forcibly grind the surface of the photoreceptor, and during the normal printing operation, the elastic roller is driven without being driven. As it does not polish the photoconductor surface as
Since the elastic roller is not always operated, problems such as jitter during printing can be solved.

In printing, the elastic roller pressed against the photosensitive member may be retracted during printing, and the peripheral speed difference between the photosensitive member and the elastic roller during printing may be made smaller than that during non-printing. Is also good. These can also solve problems such as jitter.

As described above, the polishing step is performed only in the polishing mode in which the polishing toner is supplied during non-printing and the polishing is performed by the elastic roller, so that the polishing step and the printing step are separated. It can be supplied and is not polished using untransferred toner at the time of printing, and is not affected by the printing pattern.

[0011]

Embodiments of the present invention will be described below. The present invention relates to an electrophotographic apparatus using an a-Si photosensitive drum, wherein the surface roughness of the photosensitive drum is reduced to Rz5.
In order to provide an apparatus for polishing under 00 °, FIG.
FIG. 1 is an explanatory diagram of a schematic configuration of a printer to which the present invention has been applied. FIG. 2 is an explanatory view of a main part of the photosensitive drum and the polishing roller.

An exposure source 3, a developing roller 4 (developing means and supply means), a transfer roller 5, a polishing roller 6 (polishing means), a cleaning blade 9 (polishing means), and a static eliminator along the rotation direction of the photosensitive drum 1. 10, a charger 2 is provided, and, as is well known, after the charge is removed by the charge remover 10, an exposure latent image is recorded by the exposure source 3 on the photoreceptor 1 uniformly charged by the charger 2, and the exposure latent image is recorded. To the developing roller 4 by reversal development
The toner image is transferred to the transfer paper 11 by the transfer roller 5.

The untransferred toner not transferred by the transfer roller 5 removes residual toner from the surface of the photosensitive drum 1 by a polishing roller 6 and a cleaning blade 9, and thereafter,
The removed residual toner is conveyed to a waste bottle (not shown) by a toner collecting device such as a collecting screw 8.

Reference numeral 14 denotes a cleaning device, which is a photosensitive member 1
And a cleaning blade 9, which is a polishing system for polishing the surface of the photoreceptor. The polishing roller 6 has a spring 7 for applying a constant pressure to the surface of the photoconductor. The configuration of the polishing roller 6 is covered with urethane foam rubber via a shaft. The rubber hardness is adjusted to 50 degrees via the shaft.

FIG. 2 is a view showing a mechanism for polishing the polishing roller 6 of the present invention. As shown in the figure, the drive sources of the photoreceptor 1 and the polishing roller 6 are independently provided, and 12 is a drive gear for transmitting a rotational drive from a power source A for transmitting power to the polishing roller 6 side. On the other hand, reference numeral 1b denotes a drive gear for transmitting rotation to the photosensitive drum 1 from a power source B for transmitting power to the photosensitive drum 1.

When the photosensitive drum 1 is polished by the polishing roller 6 during non-printing, the peripheral speed ratio between the photosensitive drum 1 and the polishing roller 6 is 1 to 10 (however, 1 is not included).
The power source A is rotated so that the polishing roller 6 rotates at a high speed, preferably 1 to 5 times (excluding 1).

Reference numeral 13 denotes a clutch for transmitting the power from the driving gear 12 to the polishing roller 6, and a clutch gear 13a disposed on the side for transmitting rotation from the power source of the polishing roller 6 to the polishing gear 13a.
Gear 13b for transmitting rotation to the polishing roller 6 and a clutch unit 13 for transmitting or not transmitting power
c. Reference numeral 6a denotes a drive gear disposed at the end of the shaft 6b of the polishing roller 6, which transmits power from the clutch gear 13b. Reference numeral 6c denotes a sliding member which applies a pressing force C (pressing of the spring 7 in FIG. 1) to the shaft 6b of the polishing roller 6 in the direction of the arrow to press the surface of the polishing roller 6 against the surface of the photosensitive drum 1. The member 6c is fixed and pressed down while sliding by the rotation of the polishing roller 6. Although not shown in the drawing, the polishing roller 6 that has been pressed against the surface of the photosensitive drum 1 is separated and retracted by releasing the pressing direction of the sliding member 6c.

The control at the time of printing, which is a feature of the present invention, is performed by controlling the power source A so as to reduce the peripheral speed ratio between the photosensitive drum 1 and the polishing roller 6. , The pressing force C is released to retract the polishing roller, the clutch 13 is disengaged, the transmission from the power source A to the polishing roller 6 is prevented, and the photosensitive drum 1 is driven to rotate.

FIG. 5 shows a layer structure of the photosensitive drum 1, and FIG.
0 is a conductive substrate, 21 is a photoconductive layer, and 22 is a surface protective layer. The photoreceptor used in the present invention is different from the conventional photoreceptor in the surface protective layer 22. The surface protection layer 22 is made of a-Si
It is composed of C: H, and its element ratio is represented by composition formula a-Si
_1-X C _X : When expressed as H, the value of X is 0.95 ≦ X <
1.00, preferably 0.96 ≦ X <0.98,
Further, the surface has a dynamic indentation hardness of 45 to 300 kgf /
It is in mm ^2.

By setting the value of X to 0.95 or more, the hardness becomes small and the surface is easily shaved, and a fresh surface always appears by polishing with the polishing roller 6 together with the polishing toner. When it is less than 30, the dynamic indentation hardness can be easily set to 45 kgf / mm ² or more.

The dynamic indentation hardness of the surface is 45 to 3
00 kgf / mm ² , preferably 50 to 220 kgf /
It is in mm ^2. As described above, since the hardness is set to 300 kgf / mm ² or less as compared with the conventional a-SiC: H surface protective layer, the surface is appropriately polished by the interaction between the polishing toner and the polishing roller 6 to expose the photosensitive layer. The discharge products adhered to the surface protection layer 22 of the body drum 1 can be polished. On the other hand, by setting the hardness to 45 kgf / mm ² or more, the shaving amount to be shaved by the polishing roller 6 does not become too large, and the life is extremely shortened as compared with the conventional a-SiC: H. Absent.

The dynamic indentation hardness is such that the film thickness is 1
This is an effective hardness evaluation method for evaluating the hardness of a thin film of 0 μm or less, a test load is applied to the surface of the thin film with a triangular pyramid indenter, and the indentation depth of the indenter at that time is measured.
This is the hardness that is determined by further calculation. In this measurement, an ultra-micro hardness tester DUH-201 manufactured by Shimadzu Corporation was used.

Further, instead of the surface protective layer 22, a-Si
C: H The hardness of the surface protective layer may be gradually reduced from the interface side with the photoconductive layer 21 toward the surface of the surface protective layer 22, and the other layer configurations may be the same. That is, when the configuration is made smaller in this way, the discharge products that have entered the concaves on the unevenness existing on the surface of the surface protective layer 22 at the initial stage of using the photosensitive drum 1 are removed. Irregularities can be removed by flattening, and by polishing with the polishing roller 6, the irregularities are gradually reduced to reduce irregularities, thereby easily removing products adsorbed on the surface. As the surface is abraded, the hardness of the surface is increased accordingly, and the amount of abrasion due to the polishing is reduced, thereby preventing the surface from being damaged. As the surface is scraped in this way, the surface roughness of the photoreceptor becomes 500
Å Polished below. The photoreceptor used in the present invention is a special photoreceptor having a structure capable of shaving the surface as described above, but is not limited thereto.

Next, the operation of the present invention will be described. In the normal printing operation, printing is performed in a state where the driving force to the polishing roller 6 is cut off by the clutch 13, and the polishing roller 6 rotates following the photosensitive drum 1. The non-printing time according to the present invention refers to a time when the machine is started up and when the normal printing operation performed every 10,000 sheets is different from the normal printing operation. 13 drives the polishing roller 6 pressed against the photoreceptor 1 by the spring 7. On the other hand, the charging voltage is set to 0 volt, and a developing bias of a predetermined voltage is applied to transfer the polishing toner from the developing roller 4 to the entire surface of the photosensitive drum 1 and carried to the polishing roller 6. The polishing toner is forcibly polished.

The toner is preferably a toner to which abrasive particles have been added in order to promote the polishing effect. In this way 50
On the surface of the a-Si photosensitive drum polished so as to be 0 ° or less, ion products are hardly attached and easily removed, so that image flow can be suppressed.

Hereinafter, embodiments of the present invention will be described. <Example 1> (Preparation of photoconductor and photoconductor polishing system) 30 mm in diameter
× Using an a-Si photosensitive drum manufactured in a size of 254 mm in length, 1% printing on A4 paper was performed. To the toner, 3% of titanium oxide is added as an abrasive, and a foamed EPDM roller (outer diameter 11 mm, sponge thickness 1.5 mm, hardness H
(S35 degrees), and apply a load of 200 to the photosensitive drum surface.
g / cm, and the peripheral speed ratio between the photosensitive drum and the polishing roller is 1: 2.
And a system for polishing the photoreceptor was provided. In addition,
A screw for collecting toner was disposed at a position opposite to the photosensitive drum of the polishing roller. The polishing roller was provided with a clutch so that the driving and the driving can be switched by an electric signal. The driving was set during the normal printing operation and the driving was performed in the forced polishing mode other than the normal printing operation. The forced polishing mode was set so as to operate every 10,000 wafers when the machine was started, and the operation time was 10 seconds.

(Printing test) KYOCERA FS-17 printing
00, and the image flow is H.00. H. Environment (30 ℃ 80
% RH) The image was confirmed after standing for 8 hours. The image flow is determined by rank, where 1 is a good side and 5 is a bad side.
The practical area was set to rank 1.5 or higher. The surface roughness of the photoreceptor drum after printing was measured using an atomic force microscope (AF).
According to M), 10-point average roughness (Rz) at a length of 100 μm
I asked.

The evaluation of the image deletion rank is as follows. 1: No fog was observed on the background portion of the print. 2: By using a loupe, fog is slightly observed in the background portion. 3: Fog is slightly observed in the background portion of the print by visual observation. 4: Fog is visually observed in the background. 5: Vertical streaks and the like appeared in the background portion, and remarkable fog was observed.

FIG. 3 shows the results obtained by this experiment. From the results, it was found that by performing printing, the surface roughness was improved, no image deletion occurred, and a good image without jitter or the like was obtained during non-printing.

<Second Embodiment> The same as the first embodiment except that the peripheral speed ratio between the polishing roller and the photosensitive drum is set to 1.2: 1 during normal printing and set to be lower than the peripheral speed ratio in the polishing mode. An experiment was performed. As a result, no image defect due to the influence of jitter was observed.

<Comparative Example 1> Without providing a forced polishing mode,
The same experiment as in the example was conducted except that the apparatus was used to polish the drum surface using untransferred toner during normal printing. The result obtained by this experiment is shown in FIG. From this result,
Since the printing rate was as low as 1%, the supply of the toner containing the abrasive to the polishing roller was small, and image deletion due to insufficient polishing was observed. This is because the drum surface is not polished effectively as compared with the embodiment, and an image flow is generated without completely removing ion products adhered to the photosensitive member surface. In other words, when the surface of the photoconductor drum is forcibly polished so that the surface of the photoconductor drum becomes smooth as in the present invention, the surface roughness of the photoconductor drum can be reduced to about 500 ° or less, and the image flow can be efficiently performed. And an image free from image defects such as jitter during printing can be obtained.

Comparative Example 2 The same experiment as in Example 1 was conducted except that the peripheral speed ratio between the polishing roller and the photosensitive drum was set to be the same during normal printing. As a result, image defects appeared due to the influence of jitter.

[0033]

As is apparent from the above description, according to the present invention, it is possible to suppress the image flow and to prevent the image defect due to the jitter at the time of printing.
Further, according to the present invention, since the heater temperature can be reduced, the heater capacity can be reduced, and the heater can be eliminated, energy can be saved and the heater warm time can be shortened.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a printer to which the present invention is applied.

FIG. 2 is an explanatory diagram of main parts of a photosensitive drum and a polishing roller.

FIG. 3 is a diagram showing the transition of the surface roughness of the photosensitive drum and the flow of the image with respect to the number of printed sheets (when the machine is started with A1 paper 1% printing and when a mode for forcibly polishing every 10,000 sheets is provided).

FIG. 4 is a diagram showing the transition of the surface roughness of the photosensitive drum and the flow of the image with respect to the number of printed sheets (when the photosensitive drum is polished with untransferred toner during normal printing with 1% A4 paper printing).

FIG. 5 is an explanatory view of a photoreceptor of the present invention.

[Explanation of symbols]

 1: Photoreceptor 2: Charger 3: Exposure source 4: Developing roller 5: Transfer roller 6: Polishing roller 7: Spring 8: Toner recovery screw 9: Cleaning blade 10: Static eliminator 11: Transfer paper 12: Clutch

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiromichi Ninomiya 3-5 Koikodai, Seika-cho, Soraku-gun, Kyoto Prefecture F-term in the Central Research Laboratory, Kyocera Corporation 2H027 DA35 DA36 DA36 EA09 ED27 HB19 JA01 2H034 AA05 CB01 2H068 DA01 FA16 FC15 FC20 2H077 AD02 AD06 FA22

Claims (3)

[Claims] 1. An electrostatic latent image carrier using an amorphous silicon photoreceptor, a developing means for forming a toner image on the electrostatic latent image with a polishing toner containing an abrasive, and a supplying means for supplying the polishing toner A polishing means for pressing an elastic roller against the surface of the photoreceptor and rotating the elastic roller to polish the surface of the photoreceptor, wherein the polishing toner supplied by the supply means and the polishing means In the image forming apparatus configured to print the toner image on paper while polishing the surface roughness of the photoreceptor to 500 ° or less by the interaction with, the polishing toner supply unit supplies the polishing toner during non-printing, The surface of the photosensitive member is polished so that the elastic roller has a peripheral speed difference with respect to the rotation of the photosensitive member. On the other hand, during printing, the elastic roller pressed against the photosensitive member is driven. By stopping the image forming apparatus, wherein said elastic roller is configured to perform a driven rotation that rotates with the rotation of the photosensitive member. 2. An electrostatic latent image carrier using an amorphous silicon photoreceptor, developing means for forming a toner image on the electrostatic latent image with a polishing toner containing an abrasive, and supplying means for supplying the polishing toner A polishing means for pressing an elastic roller against the surface of the photoreceptor and rotating the elastic roller to polish the surface of the photoreceptor, wherein the polishing toner supplied by the supply means and the polishing means In the image forming apparatus configured to print the toner image on paper while polishing the surface roughness of the photoreceptor to 500 ° or less by the interaction with, the polishing toner supply unit supplies the polishing toner during non-printing, The surface of the photoconductor is polished so that the elastic roller has a peripheral speed difference with respect to the rotation of the photoconductor. On the other hand, during printing, the elastic roller pressed against the photoconductor is retracted. An image forming apparatus comprising Rukoto. 3. An electrostatic latent image carrier using an amorphous silicon photoreceptor, developing means for forming a toner image on the electrostatic latent image with a polishing toner containing an abrasive, and supplying means for supplying the polishing toner A polishing means for pressing an elastic roller against the surface of the photoreceptor and rotating the elastic roller to polish the surface of the photoreceptor, wherein the polishing toner supplied by the supply means and the polishing means In the image forming apparatus configured to print the toner image on paper while polishing the surface roughness of the photoreceptor to 500 ° or less by interaction with the above, the polishing toner supply unit supplies the polishing toner during non-printing. The rotation of the photoconductor is performed while the elastic roller has a peripheral speed difference with respect to the rotation of the photoconductor. An image forming apparatus characterized by being configured so as to reduce.