JP2007033848A - Charging process evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging process evaluation method capable of easily and properly evaluating whether an electrostatic charging process is satisfactory or not. <P>SOLUTION: At least a photoreceptor 1 or a charging roller 13 disposed without being in electrical contact with the photoreceptor 1 is stopped. An AC voltage overlapped by a DC voltage for a fixed period of time is applied to the charging roller 13 and thereby the photoreceptor 1 is charged. Then, from information about the width of the trace of discharge caused in the photoreceptor 1 or charging roller 13 and information about its depth, whether a charging process is satisfactory or not is evaluated in terms of, for example, validity for electrostatic charging conditions, the electrical characteristics of the photoreceptor 1 and charging roller 13, and a gap G between the photoreceptor 1 and charging roller 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for evaluating a charging process in which a member to be charged is charged by a charging member.

  In an image forming apparatus using an electrophotographic process, a charging process for uniformly charging a photoconductor as an image carrier, an exposure process for forming an electrostatic latent image based on image information, and developing the electrostatic latent image with toner. A toner image is formed on the photoreceptor through a developing step. Then, an image is formed on the transfer material through a transfer process for transferring the toner image to the transfer material and a fixing process for fixing the toner image on the transfer material. In the charging process, a non-contact charging device such as a scorotron charger has been used conventionally, but harmful gases such as ozone and NOx are generated with corona discharge. Therefore, a contact charging type charging device is used in which a charging roller as a charging member is brought into contact with the photosensitive member to charge the photosensitive member. In this contact charging type charging device, generation of harmful gases such as ozone and NOx is small, and the device can be miniaturized. However, if the residual toner after transfer is not completely removed from the photoreceptor, the residual toner adheres to the charging roller, resulting in variations in the resistance of the charging roller, and variations in the charging potential of the photoreceptor. This was the cause of uneven image density.

  In view of this, there has been proposed a charging device of a proximity charging system in which a charging roller is disposed in proximity to a photosensitive member so as not to be in electrical contact (eg, Patent Documents 1, 2, and 3). In this proximity charging type charging device, a gap is formed between the charging roller and the photosensitive member, so that the residual toner hardly adheres to the charging member.

JP 2002-108095 A JP 2004-264792 A JP-A-2005-4000

  In the proximity charging method described above, the charging potential of the photosensitive member can be set to a target voltage by applying an AC voltage in which a DC voltage is superimposed on the charging roller. The parameters of the charging conditions at this time include the DC voltage and AC voltage to be applied and their frequencies, the electrical characteristics of the photosensitive member and the charging roller, and the interval between the photosensitive member and the charging roller. The applied AC voltage determines the distance between the photosensitive member and the charging roller that can cause discharge. The larger the AC voltage applied, the more the discharge can occur even if the distance between the photosensitive member and the charging roller is increased. That is, as the alternating voltage applied is larger, discharge occurs in a wider area of the charging roller, and the charging unevenness of the photosensitive member can be reduced. Therefore, in reality, since there are variations in electrical characteristics (resistance unevenness, etc.) in the photoconductor and the charging roller, the applied AC voltage is often set high. However, since discharging is a process in which charged particles such as ions and electrons are exposed to the photosensitive member and the charging roller, oxidation deterioration of the photosensitive member and the charging roller occurs. When the alternating voltage to be applied is large, the amount of charged particles generated increases especially where the distance between the photoconductor and the charging roller is small. Therefore, the oxidative deterioration of the photoconductor and the charging roller becomes severe at that portion, and the photoconductor and the charging roller. Must be replaced early. Further, the frequency of the AC voltage to be applied determines the number of times that discharge can occur per unit time. That is, the charging unevenness of the photosensitive member can be reduced as the frequency of the applied AC voltage is increased. Therefore, as described above, in reality, there are variations in electrical characteristics between the photoconductor and the charging roller, and therefore the frequency of the applied AC voltage is often set high. However, when the frequency of the AC voltage is large, the photoconductor and the charging roller are oxidatively deteriorated, and the photoconductor and the charging roller must be replaced early.

  In addition, if the distance between the photosensitive member and the charging roller is too short, no discharge occurs, and no discharge occurs below about 7 μm according to Paschen's law. In reality, due to the electric capacity of the photoconductor and the resistance of the charging roller, it is said that the distance between the photoconductor and the charging roller where discharge begins to occur is approximately 20 μm or more. Although it is important to control the distance between the photoconductor and the charging roller in units of μm, in reality, the charging roller has a surface roughness in units of μm. In many cases, the AC voltage and the frequency value are set higher.

  In this way, it is necessary to select charging conditions that do not cause uneven charging in the charging process, and the charging conditions are determined in consideration of variations in the electrical characteristics and dimensions of the photoreceptor and charging roller. It is easy to select the charging conditions that are likely to cause the phenomenon. Therefore, it is necessary to set the life of the photoconductor and the charging roller to be short and to replace the photoconductor and the charging roller in a short cycle.

  However, in order to reduce maintenance costs and replacement costs, it is desirable to set charging conditions that are as gentle as possible. However, until now, it has been difficult to see exactly where charging (discharging) occurs. For this reason, it has been difficult to evaluate the quality of the charging process, such as appropriateness of charging conditions, variation in the distance between the photosensitive member and the charging roller (dimensional accuracy), and variation in electrical characteristics of the photosensitive member and the charging roller. Although it is possible to estimate the quality of the charging process to some extent by measuring the charging potential of the photoconductor, the charging potential of the photoconductor can also be measured only in a few limited places, and the quality of the charging process can be evaluated appropriately. It was not a thing. In actual image formation, discharge is performed while rotating the photosensitive member and the charging roller, so that the entire surface of the photosensitive member and the charging roller is basically uniformly oxidized and decomposed. For this reason, when trying to evaluate the quality of the charging process (quality or life of the photoconductor or charging roller), the discharge must be performed until a decrease in the diameter of the photoconductor or charging roller can be confirmed. Cost. In addition, since the amount of decrease in the diameter of the photoconductor and the charging roller is small, the reliability of the evaluation is low.

  The present invention has been made in view of the above problems, and an object thereof is to provide a charging process evaluation method capable of easily and appropriately evaluating the quality of a charging process.

In order to achieve the above object, the charging process evaluation method according to claim 1 stops at least one of the charging member and a member to be charged that is electrically non-contacted with the charging member, and makes the charging member constant. The object to be charged is charged by applying an alternating voltage on which a time direct voltage is superimposed, and the quality of the charging process is evaluated based on the discharge mark generated on the charging member or the object to be charged.
The charging process evaluation method according to claim 2 is characterized in that, in the charging process evaluation method according to claim 1, the quality of the charging process is evaluated based on width information of discharge marks generated on the charging member or the body to be charged. Is.
The charging process evaluation method according to claim 3 is characterized in that, in the charging process evaluation method according to claim 1, the quality of the charging process is evaluated based on depth information of discharge marks generated on the charging member or the charged body. To do.
The charging process evaluation method according to claim 4 is the charging process evaluation method according to claim 3, wherein the life of the charging member or the member to be charged is estimated based on depth information of a discharge mark generated on the charging member or the member to be charged. It is characterized by doing.
A charging process evaluation method according to a fifth aspect is the charging process evaluation method according to the first, second, third, or fourth aspect, wherein the member to be charged is a photosensitive member used for image formation, and the charging member is electrically connected to the photosensitive member. The charging roller is disposed in a non-contact manner, and is a charging roller that charges the photosensitive member by applying an AC voltage on which a DC voltage is superimposed.

  As a result of intensive investigations, the present inventors have found the following as to whether there is a method for easily evaluating whether or not the charging process is operating well. In a charging process in which a charged member is charged by applying an AC voltage superimposed with a DC voltage to a charging member that is arranged in a non-contacting manner with the charged member in a non-contact manner, a part of the energy from the discharge is charged to the charged member or the charged member. The higher the C—C bond of the organic material of the member is cut. Therefore, if at least one of the member to be charged and the charging member is stopped and an AC voltage on which a DC voltage is superimposed is applied, a discharge occurs only at a portion where the member to be charged and the charging member face each other, and a discharge occurs at the other portion. In other words, streaky defect portions, so-called discharge marks, are generated on the charged object and the charging member that are stopped. By looking at the discharge marks, it is possible to easily and appropriately evaluate the quality of the charging process, such as the validity of the charging conditions, variations in the electrical characteristics between the charged body and the charging member, and variations in the distance between the charged body and the charging member. can do.

  According to the present invention, there is an excellent effect that a charging process evaluation method capable of easily and appropriately evaluating the quality of a charging process can be provided.

  Hereinafter, the evaluation method of the charging process according to the present embodiment will be described. First, the configuration of an image forming apparatus on which a photosensitive member that is a member to be evaluated and a charging roller that is a charging member that are evaluated in the present embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus. The image forming apparatus shown in FIG. 1 is configured as a copier, a printer, a facsimile, or a multifunction machine having at least two of these functions. In this image forming apparatus, a photosensitive member 1 to be charged is arranged in a main body housing (not shown), and is rotated in the clockwise direction in FIG. 1, and its surface moves in the direction of arrow A. The photoreceptor 1 is composed of a photoreceptor in which a photosensitive layer 3 is laminated on the outer peripheral surface of a drum-shaped conductive base 2. The photosensitive member may be a belt-shaped photosensitive member that is driven by being wound around a plurality of rollers, or a drum-shaped or belt-shaped photosensitive member made of a dielectric. Around the photoreceptor 1, a static elimination lamp 4, a charging device 5, a laser writing unit 6, a developing device 7, a transfer device 8, and a cleaning device 12 are arranged.

  In the image forming apparatus having the above-described configuration, the photosensitive member 1 is rotationally driven during the image forming operation, the surface of the photosensitive member 1 is irradiated with light from the static elimination lamp 4, and the surface thereof is initialized. The surface of the body 1 is charged with a predetermined polarity. The surface of the photosensitive member 1 charged by the charging device 5 is irradiated with light-modulated laser light L emitted from a laser writing unit 6 which is an example of an exposure device, whereby an electrostatic latent image is formed on the surface of the photosensitive member 1. It is formed. Next, the electrostatic latent image is visualized as a toner image by toner charged to a predetermined polarity when passing through the developing device 7. On the other hand, a transfer material P made of, for example, transfer paper is fed between the transfer device 8 and the photoconductor 1 facing the photoconductor 1 at a predetermined timing. At this time, the toner formed on the photoconductor 1 The image is electrostatically transferred onto the transfer material P. The transfer material P to which the toner image has been transferred continues to pass between the fixing roller 10 and the pressure roller 11 of the fixing device 9, and at this time, the toner image is fixed on the transfer material P by the action of heat and pressure. The transfer residual toner that is not transferred to the transfer material P and remains on the surface of the photoreceptor 1 is removed by the cleaning device 12.

  The charging device 5 includes a charging roller 13 that is a charging member disposed opposite to a moving charging member surface, in the illustrated example, the surface of the photosensitive member 1, and a power source 14 that applies a voltage to the charging roller 13. Yes. The power supply 14 applies an AC voltage superimposed with a DC voltage to the charging roller 13, and generates a discharge between the charging roller 13 and the surface of the photoconductor 1 to charge the surface of the photoconductor 1 to a predetermined polarity. The charging roller 13 is made of, for example, a cylindrical conductive core bar (stainless steel or the like). An elastic layer made of a rubber or plastic material may be provided on the outer side of the metal core because the photoconductor may be damaged by contact with the photoconductor when the charging roller is assembled. Further, a high resistance thin layer may be provided on the elastic layer.

  The charging roller 13 is opposed to the surface of the photoreceptor 1 with a minute gap G of, for example, 10 μm to 150 μm so as not to be in electrical contact. FIG. 2 is a configuration diagram showing a configuration example for placing the charging roller 13 on the surface of the photosensitive member 1 with a minute gap G therebetween. As shown in FIG. 2, for example, a spacer made of a tape 20 is attached to each end region in the longitudinal direction of the charging roller 13, and the charging roller 13 is brought into contact with the surface of the photoreceptor 1. A minute gap G is maintained with respect to the surface of the photoreceptor 1. In addition, a minute gap can be secured using a flange or the like.

  In the present embodiment, whether the charging process works well in the charging device 5 is evaluated by the following method. That is, when an AC voltage in which a DC voltage is superimposed for a certain period of time is applied to the charging roller 13 without rotating either one or both of the photosensitive member 1 and the charging roller 13, a part of the energy generated by the discharge is charged to the photosensitive member 1 and the charging roller 13. The C—C bond of the organic substance of the roller 13 is cut, and a discharge mark is formed only at a place where the photoreceptor 1 and the charging roller face each other. The quality of the charging process is evaluated by this discharge mark. FIG. 3 is a conceptual diagram showing the shape of discharge marks on the surface of the photoreceptor. FIG. 4 is a conceptual diagram showing another shape of the discharge trace on the surface of the photoreceptor. As shown in FIG. 3, for example, it is assumed that one discharge mark having a width a is formed on the surface of the photoreceptor 1 in the circumferential direction of the photoreceptor 1. If there is no variation in the axial direction in the minute gap G between the photoconductor 1 and the charging roller 13, the width a is constant in the axial direction as shown in FIG. Further, if the small gap between the photosensitive member and the charging roller is partially smaller than the discharge limit, no discharge occurs in that portion, so that discharge traces having widths a ′ and a ″ are formed as shown in FIG. Two are formed. On the other hand, when the minute gap G between the photosensitive member 1 and the charging roller 13 varies in the axial direction, the widths a, a ′, and a ″ of the discharge marks are not constant. Similarly, the shape of the discharge mark also changes due to uneven electric capacity of the photoreceptor 1 and uneven resistance of the charging roller 13. As described above, it is possible to easily verify variations in dimensional accuracy / assembly accuracy and electrical characteristics between the photosensitive member 1 and the charging roller 13 by the shape of the discharge trace. As a result, it is possible to easily predict the ease of occurrence of charging potential unevenness when normal charging is performed using the photosensitive member 1 and the charging roller 13, and whether the charging process operates satisfactorily and appropriately. Can be evaluated.

  Further, in the charging method evaluation method described above, discharge occurs only at a location where the photoconductor 1 and the charging roller 13 face each other, and the surface of the photoconductor 1 and the charging roller 13 is oxidized and decomposed only at that location to reduce the diameter. Become. On the other hand, there is no change in the photosensitive member 1 and the charging roller 13 in a place where no discharge occurs. For this reason, it is easy to obtain depth information of the location of the discharge trace if the location where no discharge is generated is used as a reference. The depth information of the discharge trace may be considered as damage directly received by the photoreceptor 1 or the charging roller 13 due to the discharge, and the time from the decrease in the film thickness of the photoreceptor 1 or the charging roller 13 due to the discharge to the lifetime can be easily predicted. can do. Specifically, if the width of the discharge mark is known as amm, it can be considered that the acceleration test is π · b / a times when the diameter of the photoreceptor 1 or the charging roller 13 is bmm. For example, if a discharge trace having a width of 1.5 mm is generated on the photoreceptor 1 having a diameter of 30 mm, this corresponds to an acceleration experiment of π × 30 / 1.5 = 62.8 times. In actual image formation, the photosensitive member 1 and the charging roller 13 are always rotated and a portion where charging is not always performed always occurs. Therefore, discharge is less likely to occur compared to the evaluation method of the charging process. The process evaluation method is a further accelerated test.

  In the above-described evaluation method of the charging process, if the width of the discharge mark is a (mm), the linear velocity of the photosensitive member 1 is v (mm / s), and the frequency of the applied AC voltage is f (Hz), v It can be seen that charging potential unevenness is likely to occur unless / f <a. FIG. 5 is a conceptual diagram showing the shape of a discharge mark when charging potential unevenness does not occur on the photoconductor. FIG. 6 is a conceptual diagram showing the shape of a discharge mark when charging potential unevenness occurs on the photoreceptor. FIG. 7 is a conceptual diagram showing the shape of the discharge trace when the discharge trace is divided into two and uneven charging potential occurs. As shown in FIG. 5, when the discharge trace satisfies v / f <a, uneven charging potential hardly occurs and a substantially uniform charging potential can be obtained in the circumferential direction of the photoreceptor 1. On the other hand, as shown in FIG. 6, when the discharge trace satisfies v / f> a, charging potential unevenness is likely to occur in the circumferential direction of the photoreceptor 1, which is not preferable. In addition, as shown in FIG. 7, when the interval between the photosensitive member 1 and the charging roller 13 is small and the discharge trace is divided into two, even if v / f> a, charging potential unevenness occurs. It will occur. In such a case, the widths a ′ and a ″ (see FIG. 4) should be used as the discharge width.

  Also, in fact, even in the discharge trace, that is, where the discharge is occurring, the density of the discharge is higher in the place where the distance between the photoconductor and the charging roller is closer than in the place where the distance is far, so there is a difference in the charging potential. Yes. For this reason, the value of the width a of the discharge trace may be set small from the standard of uniformity of the charging potential by the image forming apparatus. In this case, for example, from the depth information of the discharge trace, it is possible to define a width a that gives a certain depth.

  In order to increase the width a of the discharge mark, the applied AC voltage (Vpp) is increased, the interval between the photosensitive member 1 and the charging roller 13 is decreased, or the diameter of the charging roller 13 is increased. Is effective. However, if the AC voltage Vpp to be applied is too large, the density at which discharge occurs is different between a place where the distance between the photoconductor 1 and the charging roller 13 is near and a place where the charge roller 13 is far away, and uneven charging potential at the place where the discharge occurs. Becomes even larger. For this reason, it is not preferable to increase the alternating voltage Vpp applied carelessly. In the present embodiment, as described above, the intensity of the discharge at the place where the discharge is generated can be easily obtained from the depth information of the discharge trace, so that the appropriateness of the AC voltage Vpp applied from the depth information of the discharge trace can be determined. It is good to evaluate sex.

  As described above, according to the evaluation method of the charging process according to the present embodiment, if the discharge trace is observed, the electrical characteristics of the photoconductor and the charging roller are varied and the dimensional accuracy is changed, the AC voltage applied to the charging roller and its frequency, In addition, the validity of charging conditions such as a minute gap between the photosensitive member and the charging roller can be easily verified. Further, the lifetime of each member can be predicted based on the depth information of the discharge marks of the photosensitive member and the charging roller. Furthermore, the quality of the photoconductor and the charging roller itself in the charging process can be evaluated. Specifically, various prescriptions, manufacturing methods, and storage conditions of the photoreceptor and the charging roller can be evaluated. When the prescription and the manufacturing method are determined, it can be suitably used for delivery inspection in each manufacturing lot, for example.

  In the evaluation method of the charging process according to the present embodiment, there is no change except for the portion where the photoconductor 1 and the charging roller 13 are opposed to each other. Therefore, a pair of the photoconductor 1 and the charging roller 13 is used. After the evaluation, the photosensitive member 1 and the charging roller 13 are slightly rotated so that the places where no discharge occurs are opposed to each other, so that a new charging process can be evaluated and evaluated. Since the photosensitive member 1 and the charging roller 13 used for the evaluation of the charging process have discharge marks, they are not mounted on the image forming apparatus but are replaced with a new photosensitive member 1 and a charging roller. Needless to say, it is mounted on the image forming apparatus.

  Also, in the charging method evaluation method according to the present embodiment, no abnormality such as heat generation occurs unless an extremely large value is used for the charging condition parameter. However, in the case of a long-time test or the like, the organic part of the photoreceptor 1 or the charging roller 13 may be decomposed and leak may occur. It is preferable to have a safety device that shuts off the supply.

Hereinafter, specific examples of the evaluation method of the charging process will be described.
[Example 1]
Three types of charging rollers were evaluated as charging rollers for a black photosensitive unit of an image forming apparatus (image Neo Neo C385 (manufactured by Ricoh)). The charging roller has a configuration in which a conductive rubber mainly composed of epichlorohydrin rubber is attached to a stainless steel cylinder, and the rubber hardness of the epichlorohydrin rubber is three types of 65, 73, and 76. . The minute gap between the photoconductor and the charging roller was formed by attaching a gap tape having a width of 10 mm and a thickness of 55 μm at a position 15 mm from the end of the charging roller. Then, a charging roller is disposed immediately above the photoconductor, the charging roller is pressed against the photoconductor with a spring, and a DC voltage of −600 V is applied between the photoconductor and the charging roller under the condition that the photoconductor and the charging roller are not rotated. An AC voltage having a frequency of 780 Hz and 2400 V was applied for 5 minutes. As a result, white streak discharge marks were generated on the charging roller and the photoreceptor. When the discharge mark near the center of the charging roller was observed, the discharge mark of the charging roller having a rubber hardness of 72 and 77 was a single streak having a width of about 1.5 mm. Two streaks having a width of about 0.6 μm were observed on both sides of a portion having no change in width of about 0.6 μm. From this result, it was evaluated that the charging roller having the rubber hardness of 65 had a higher frequency than the charging roller having the rubber hardness of 73 and 76 and was not preferable in order to perform uniform charging.

[Example 2]
The charging roller having a rubber hardness of 65 in Example 1 was further charged for 20 minutes. When the charging roller was observed, there was only one discharge mark up to 15 mm on the inner side where the gap tape was attached, but there were two discharge marks inside, and the width of the area where there was no change between the discharge marks. The center of the charging roller was the widest.
Therefore, a new charging roller having a rubber hardness of 65 is mounted on the image forming apparatus (image Neo Neo C385 (manufactured by Ricoh)), both the photosensitive member and the charging roller are rotated, and a DC voltage of −600 V is applied to frequencies of 780 Hz and 2400 V. An alternating voltage was applied, that is, normal charging was performed. The charging potential unevenness on the surface of the photoreceptor corresponding to the position of 15 mm inside the center of the charging roller and the gap tape was measured. As a result, the charging potential unevenness on the surface of the photoreceptor corresponding to the position of 15 mm inside the gap tape was 8 V or less, but the charging potential unevenness on the surface of the photoreceptor corresponding to the center was 14 V. Again, it was determined that a charging roller with a rubber hardness of 65 was not preferred in this charging process. This is because a charging roller having a rubber hardness of 65 can maintain the gap G at a predetermined size in the vicinity of the gap tape, but since the hardness is small and it is easily bent, the gap G becomes smaller than the predetermined size near the center.

[Example 3]
A charging roller having a rubber hardness of 73 was charged for 25 minutes under the same conditions as in Example 1. When the depth of the discharge mark near the center of the charging roller was measured, the 0.2 to 1 μm additive dispersed in the epichlorohydrin rubber of the charging roller was completely exposed. From this, it was found that the charging roller was etched by about 1 μm by charging for 25 minutes.
[Comparative Example 1]
A new charging roller with a rubber hardness of 73 is mounted on an image forming apparatus (image Neo Neo C385 (manufactured by Ricoh)), both the photosensitive member and the charging roller are rotated, and a DC voltage of −600 V is applied to a frequency of 780 Hz and an AC voltage of 2400 V. And only charging was performed for 5 hours. An attempt was made to measure the outer shape of the charging roller, but the change in the outer shape due to charging could not be measured.
In Example 3, the etching speed was obtained from the depth of the discharge trace, and the life of the charging roller could be easily estimated, whereas in Comparative Example 1, the life of the charging roller was small and the life was small. It was difficult to estimate.

[Example 4]
The charging roller having a rubber hardness of 76 was charged for 60 minutes under the same conditions as in Example 1, with the AC frequency applied being 780 and 950 Hz. When the depth of the discharge mark near the center of the charging roller was measured with a laser microscope VK-9500 (manufactured by Keyence), it was etched by 2.2 μm and 2.8 μm, respectively, when the frequencies were 780 and 950 Hz. It was evaluated that the life of the charging roller was longer when the frequency was 780 Hz.
A new charging roller having a rubber hardness of 76 is mounted on an image forming apparatus (image Neo Neo C385 (manufactured by Ricoh)), both the photosensitive member and the charging roller are rotated, a DC voltage of −600 V is applied to frequencies of 780 and 950 Hz, and 2400 V. An AC voltage was applied for charging. When charging unevenness at the center of the charging roller was measured and found to be 8 V or less at both frequencies, 780 Hz was adopted as the charging condition.

As described above, according to the evaluation method of the charging process according to the present embodiment, the discharge mark is formed on the photosensitive member 1 that is a member to be charged or the charging roller 13 that is a charging member. is there. Therefore, the quality of the charging process can be evaluated easily and appropriately.
Further, according to the evaluation method of the charging process according to the present embodiment, it is possible to verify the occurrence of charging potential unevenness and the validity of the charging condition from the information on the width of the discharge trace, and easily and appropriately evaluate the quality of the charging process. Can do.
Further, according to the evaluation method of the charging process according to the present embodiment, it is possible to verify the occurrence of charging potential unevenness and the validity of the charging conditions based on the depth information of the discharge trace, and easily and appropriately evaluate the quality of the charging process. be able to.
Further, according to the evaluation method of the charging process according to the present embodiment, it is easy to predict the life of the photoconductor and the charging roller, and it is easy to estimate the replacement time of the photoconductor and the charging roller.
Further, according to the evaluation method of the charging process according to the present embodiment, it is possible to select a gentle charging condition and mount a photoconductor and a charging roller that have been appropriately evaluated in the image forming apparatus.

1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus. FIG. 2 is a schematic configuration diagram illustrating a configuration of a photoreceptor and a charging roller. The conceptual diagram which shows the shape of the discharge trace on the surface of a photoreceptor. The conceptual diagram which shows another shape of the discharge trace on the surface of a photoreceptor. FIG. 3 is a conceptual diagram illustrating a shape of a discharge mark when charging potential unevenness does not occur on a photoconductor. FIG. 3 is a conceptual diagram illustrating a shape of a discharge mark when charging potential unevenness occurs on a photoreceptor. The conceptual diagram which shows the shape of the discharge trace in case a charging potential nonuniformity arises with two discharge traces.

Explanation of symbols

1 Photoconductor 13 Charging roller 20 Tape

Claims (5)

  At least one of the charging member and the member to be charged that is arranged in a non-contact manner with the charging member is stopped, and the charging member is charged by applying an AC voltage in which a DC voltage is superimposed on the charging member for a certain period of time. And a charging process evaluation method for evaluating the quality of the charging process based on discharge traces generated on the charging member or the object to be charged. In the charging process evaluation method according to claim 1,
A charging process evaluation method, wherein the quality of the charging process is evaluated based on width information of discharge marks generated on the charging member or the body to be charged. In the charging process evaluation method according to claim 1,
A charging process evaluation method, wherein the quality of the charging process is evaluated based on depth information of discharge marks generated on the charging member or the member to be charged. In the charging process evaluation method according to claim 3,
A charging process evaluation method characterized in that the life of the charging member or the member to be charged is estimated based on depth information of a discharge mark generated on the charging member or the member to be charged. In the charging process evaluation method according to claim 1, 2, 3, or 4,
The member to be charged is a photosensitive member used for image formation, and the charging member is a charging roller that is arranged in an electrically non-contact manner with the photosensitive member and applies an alternating voltage superimposed with a direct current voltage to charge the photosensitive member. The charging process evaluation method characterized by the above-mentioned.

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