JP2013044871A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of problems due to excessive lubricant application or insufficient lubricant application by appropriately maintaining lubricant amount on an image carrier such as a photoreceptor according to variation of lubricant application amount.SOLUTION: In an electrophotographic image forming apparatus which includes a lubricant application device 140 for applying lubricant on an image carrier such as a photoreceptor drum 110 and applies an AC voltage to charging means 120 for charging the photoreceptor drum 110, an AC peak-to-peak voltage (Vp-p) applied to the charging means 120 is varied in accordance with variation of consumption amount of a lubricant 141. The lubricant application device 140 constitutes a mechanism which scrapes off a solid lubricant in a bar-shape with a brush roller 142 and applies it to the photoreceptor drum 110. The AC peak-to-peak voltage (Vp-p) applied to the charging means 120 is made greater in the initial period of the use of the brush roller 142, is made smaller in the initial period of the use of the lubricant 141, and gradually made smaller according to the time of use of the brush roller 142.

Description

  The present invention relates to an electrophotographic image forming apparatus equipped with a lubricant application mechanism such as a metal soap lubricant application device.

  With the recent progress in color, high speed, and high image quality of copying machines and printers, quadruple tandem image forming apparatuses have become mainstream among electrophotographic image forming apparatuses. In addition, with increasing awareness of the environment, recycling, high reliability, and long life have become increasingly important. In addition, due to consideration for the office environment, awareness of ozone generation and dust generation is increasing.

  Therefore, many electrophotographic image forming apparatuses employ a charging roller system that generates a small amount of ozone as a charging member. Furthermore, with the aim of extending the life, a charging roller facing the photoconductor with a small gap may be employed. In addition, due to the demand for higher image quality, there are an increasing number of cases where an AC voltage is sufficiently applied to the charging roller to apply an alternating voltage that stabilizes the charging potential.

  In this type of image forming apparatus, when an AC voltage is applied to the charging roller, the surface of the photoconductor is destroyed by the charging current. Therefore, a lubricant is applied to the photoconductor to protect the surface of the photoconductor. It has become to. When a lubricant such as zinc stearate is applied to the photoreceptor, the lubricant is destroyed by a charging current instead of the photoreceptor, so that the surface of the photoreceptor is protected from destruction. Also, by applying the lubricant, it is possible to improve the cleaning performance by lowering the coefficient of friction of the photoreceptor surface and stabilizing the behavior of the cleaning blade edge.

  FIG. 1 is a sectional view conceptually showing the internal mechanism of the four-tandem image forming apparatus as described above. The image forming apparatus 1 forms a color image using toner of each color of yellow (Y), magenta (M), cyan (C), and black (K). The image forming apparatus 1 has a configuration in which a sheet feeding unit 10 in which sheet feeding cassettes 11 and 12 that store sheets as recording media are disposed is provided below, and an image forming unit 20 and a transfer unit 30 are disposed above the sheet feeding unit 10. .

  The image forming unit 20 includes photosensitive drums 110Y, 110M, 110C, and 110K (hereinafter referred to as the photosensitive drum 110 unless otherwise specified), which are image carriers. Four image forming units 100Y, 100M, 100C, and 100K are provided. The transfer unit 30 includes an intermediate transfer belt 34 as an intermediate transfer member formed of a flexible endless belt wound around a plurality of rollers 31, 32, and 33, and a secondary transfer roller 35. Further, an optical writing unit 40 that is a latent image forming apparatus that forms a latent image on each of the photosensitive drums 110Y, 110M, 110C, and 110K, a fixing device 50 that fixes a toner image on a sheet, and the like are disposed. Further, a transport path 60 for transporting paper is formed between the paper feed cassettes 11 and 12 and the fixing device 50.

  Further, a belt cleaning is performed in which a secondary transfer roller 35 serving as a secondary transfer device is disposed on a portion of the intermediate transfer belt 34 facing the roller 32 so as to face the conveyance path, and the belt surface is cleaned on a portion facing the roller 31. A device 37 is installed.

  The image forming unit 20 is disposed so as to face the lower belt running side of the intermediate transfer belt 34 disposed between the rollers 31 and 32 of the intermediate transfer belt 34. In each of the image forming units 100Y, 100M, 100C, and 100K, the photosensitive drums 110Y, 110M, 110C, and 110K are disposed so as to be in contact with the intermediate transfer belt 34. In the figure, reference numerals 70Y, 70M, 70C, and 70K denote toner bottles for storing replenishment toner.

  In the image forming apparatus 1, the photosensitive drums 110Y, 110M, 110C, and 110K of the image forming units 100Y, 100M, 100C, and 100K are exposed in a predetermined pattern by the optical writing unit 40, and the photosensitive drums 110Y, 110M, 110C, and 110K is developed by the developing unit, sequentially transferred onto the intermediate transfer belt 34, transferred to the transfer sheet conveyed from the sheet feeding cassettes 11 and 12 on the sheet conveying path 60 by the secondary transfer roller 35, and fixed. It is fixed and discharged by the device 50.

  FIG. 2 is a sectional view showing the image forming unit shown in FIG. The image forming units 100Y, 100M, 100C, and 100K have the same structure as well as different toner colors. Therefore, the structure of one image forming unit 100 will be described without adding a suffix to the reference numerals. In the image forming unit 100, a charging unit 120, a developing device 130, a lubricant applying device 140, and a cleaning device 150 are arranged around the photosensitive drum 110.

  In this image forming unit, the charging unit 120 employs a charging roller that faces the photosensitive drum 110 with a gap and is applied with an AC voltage, aiming at high image quality and long life. Specifically, the charging unit 120 includes a charging roller 121 disposed with a gap (gap) in the photosensitive drum 110 and a cleaning roller 122 that removes dirt on the charging roller 121. The developing device 130 includes a developing roller 131 and stirring rollers 132 and 133.

  The cleaning device 150 contacts the photoconductor drum 110 to remove residual toner on the photoconductor drum 110, and the lubricant application blade 160 contacts the photoconductor drum 110 and applies a lubricant application device to the photoconductor drum 110. The lubricant applied at 140 is thinned. Reference numeral 153 in the drawing denotes a waste toner transport member that transports the removed waste toner.

  In the illustrated image forming apparatus, the contact area between the member to which the lubricant is applied and the surface of the image carrier such as the photosensitive drum is changed due to the change in the image area ratio, and the supply of the lubricant is excessive or insufficient. In order to prevent this, the lubricant application device 140 is disposed on the downstream side of the cleaning device 150 in the rotation direction of the photosensitive drum 110. In the following, terms such as an image carrier, a photoconductor, and a photoconductor drum are used separately, but are not limited to any one, and are used according to the context as appropriate.

  The image forming apparatus also includes a lubricant application blade 161 that contacts the photoconductor drum 110 and thins the lubricant 141 applied by the lubricant application device 140 and applies the thin film to the photoconductor drum 110. The lubricant application blade 161 is supported by a support member 162. The lubricant application blade 161 is in contact with the photosensitive drum 110 from the trailing direction. When the lubricant application blade 161 is brought into contact with the trailing direction, the amount of the lubricant 141 to be scraped off from the photosensitive drum 110 can be reduced, and therefore the application efficiency of the lubricant 141 is good.

  In such a lubricant application mechanism, the amount of the lubricant 141 applied to the photosensitive drum 110 is such that the brush roller 142 has a brush set, the lubricant 141 is new, old, etc., as shown in FIGS. 3A to 3D. It changes with.

  That is, as shown in the lubricant application amount curves of FIGS. 3E and 3F, it changes depending on the brush set, the new / old lubricant, and the like. For example, when the brush roller 142 is new and has no settling, the scraping ability of the lubricant by the brush roller 142 is large, and the amount of lubricant applied to the photosensitive drum 110 is used to some extent by the brush and the lubricant. Therefore, the amount of the lubricant applied is greater than when the application is stable, and the application tends to be excessive. When the application is excessive, the charging roller 121 is soiled by the lubricant, the roller resistance increases due to the soiling, and eventually, charging failure occurs and a vertical stripe image or the like is generated.

  On the other hand, when only the lubricant 141 is new in the replacement of the lubricant and the contact area between the brush roller 142 and the lubricant 141 is small, the scraping ability of the lubricant 141 by the brush roller 142 is small, and the lubricant to the photosensitive drum 110 is reduced. The amount of application becomes smaller than when the application is stable, resulting in insufficient application of the lubricant. If the photosensitive member protective action is insufficient, the surface of the photosensitive drum 110 is destroyed by the charging current, and filming of the surface of the photosensitive drum 110 occurs. In addition, due to insufficient lubrication of the photosensitive drum 110, a cleaning failure or the like also occurs. Furthermore, even when the brush roller 142 has been used for a long time and the brush roller 142 becomes sticky, the ability of the brush roller 142 to scrape the lubricant is reduced, and the amount of lubricant applied to the photosensitive drum 110 is stable. Smaller than time. Even in such a case, since the application of the lubricant is insufficient, the protective action of the photosensitive member is insufficient, the surface destruction of the photosensitive drum 110 proceeds, and the photosensitive member filming occurs. In addition, due to insufficient lubrication of the photosensitive member, defective cleaning or the like also occurs.

  Therefore, in Patent Document 1, in an image forming apparatus that supplies a lubricant to the surface of an image carrier by a blade cleaning method, the surface of the image carrier is obtained by uniformly applying the lubricant to the surface of the image carrier as little as possible. In order to achieve stable cleaning over the long term without causing image flow, fusing, etc., the surface of the image carrier has a cubic and / or particle shape. Alternatively, a polishing agent having a rectangular parallelepiped shape and a primary particle size of 30 nm or more and 300 nm or less and a lubricant are supplied, and the supply amount of the polishing agent is A (μg / cm ^ 2). When the supply amount is B (μg / cm ^ 2), the discharge current amount flowing from the charging member to the image carrier is ΔIac (mA), and the Taber wear amount of the image carrier is T (mg), 0.5 × ΔIac / T ≦ A + 10B ≦ 5 × ΔIac / T The invention of satisfying the relationship of 1 ≦ A / B ≦ 20 is disclosed. In the above and below, the symbol “^” indicates a power.

  Further, in Patent Document 2, the amount of lubricant applied to the surface of the photoconductor is set to an amount capable of suppressing deterioration of the surface of the photoconductor due to discharge, and the problem of maintaining the effect of applying the lubricant over a long period of time is described. And a lubricant disposed at a position where it can be applied to the surface of the image carrier charged by a charging member to which a voltage is applied, and a coating means for applying the lubricant to the surface of the image carrier. The amount of the lubricant applied to the surface of the image carrier is 25 × f × (Vpp / 2Vth) / L [nm / s] or more, and the amount of lubricant applied to the surface of the image carrier is By controlling in this way, an invention is disclosed in which the function of the lubricant can be maintained over a long period of time, and deterioration such as film scraping on the surface of the image carrier can be prevented.

  Further, in Patent Document 3, an object is to provide an image forming apparatus having a configuration in which high durability can be obtained without increasing a load on a charging unit by a relatively simple control operation. Provided with charging means that can be uniformly charged while being placed in contact with or in close proximity to the image carrier, the electrostatic latent image formed on the uniformly charged image carrier is subjected to visible image processing by a developing device Then, after transferring the visible toner image to the transfer object, a means for removing the toner remaining on the surface of the image carrier by a cleaning device, and supplying a lubricant to the image carrier And the charging means has a counter that counts the number of times of image formation or the rotation time of the image carrier, and an AC voltage value applied between image formation and non-image formation according to the counter value. Control hand to control the ratio of Characterized in that it is connected, the invention is that disclosed in.

  In view of the above-described conventional problems, the present invention maintains an appropriate amount of lubricant on an image carrier such as a photoconductor against the variation in the amount of lubricant applied as described above, resulting in excessive application of lubricant. It is an object to prevent the occurrence of problems such as contamination of the charging roller due to toner, charging failure associated therewith, streak image, photoconductor filming due to insufficient application of lubricant, and cleaning failure.

  The image forming apparatus of the present invention is an electrophotographic image forming apparatus in which a mechanism for applying a lubricant to an image carrier such as a photosensitive drum is mounted, and an AC voltage is applied to a charging member that charges the image carrier. The AC peak-to-peak voltage (Vp-p) applied to the charging member is changed in accordance with the consumption variation of the lubricant.

  According to the present invention, the amount of the lubricant remaining on the image carrier after passing through the charging member is appropriately maintained, and the image carrier is caused by the lubricant smearing of the charging member due to excessive application of the lubricant or insufficient application of the lubricant. It is possible to prevent problems such as filming and poor cleaning.

A sectional view conceptually showing an internal mechanism of a four-tandem image forming apparatus Sectional drawing which shows the image formation unit shown in FIG. Enlarged sectional view showing the operation of a conventional lubricant application mechanism The same enlarged sectional view The same enlarged sectional view The same enlarged sectional view The figure which shows the relationship between the lubricant application amount in the conventional lubricant application mechanism and the application device usage time The figure which shows the relationship between the lubricant application amount in the conventional lubricant application mechanism and the application device usage time when only the lubricant is replaced with a new one The expanded sectional view which shows the effect | action of Embodiment 1 of this invention The same enlarged sectional view The same enlarged sectional view The figure which shows the relationship between the lubricant application quantity of Embodiment 1 of this invention, and the voltage between charging alternating current peaks. Diagram showing the relationship between the amount of lubricant applied and the charging AC peak-to-peak voltage Sectional drawing which shows Embodiment 2 of this invention The same enlarged sectional view Diagram showing the relationship between the amount of lubricant applied and the charging AC peak-to-peak voltage

Embodiments of the present invention will be described below.
As described above, the amount of the lubricant applied to the image carrier such as the photoconductor varies depending on the brush setting, the new / old lubricant, etc., and the amount of the lubricant applied to the photoconductor is large. In this case, the charging roller or the like is soiled with lubricant due to overcoating, and vertical streaks due to poor charging occur. Conversely, if the amount of lubricant applied is small, the photoconductor protection action is insufficient due to insufficient application of the lubricant. Photoreceptor filming occurs and cleaning failure occurs due to insufficient lubrication. Since the lubricant maintains the photosensitive member protecting action by being destroyed and consumed by the charging current flowing through the charging member, more charging current flows when the AC peak-to-peak voltage applied to the charging member is increased. The attacking action of the charging current on the photoconductor increases, and the amount of lubricant to be destroyed and consumed is necessary for protecting the photoconductor.

  When the amount of lubricant applied is large, such as when the lubricant application brush is new, the AC peak-to-peak voltage is greater than the normal value (when the amount of lubricant applied is stabilized by using a certain amount of brush / lubricant, etc.). On the other hand, if the lubricant application brush is worn out and the amount of wet lubricant applied is small, the AC peak-to-peak voltage will be made smaller than the normal value. In addition, the AC peak-to-peak voltage applied to the charging member is changed. As a result, the amount of lubricant remaining on the photosensitive member after passing through the charged portion is properly maintained, and problems such as charging roller contamination due to excessive application of lubricant, filming of the photosensitive member due to insufficient application of lubricant, and poor cleaning occur. Can be prevented.

  In the following description, the same or similar parts as those in the conventional example will be described with the same reference numerals.

<Embodiment 1>
4A to 4E show Embodiment 1 of the present invention. In the present embodiment, the lubricant application device 140 is provided on the downstream side in the rotation direction of the photosensitive drum 110 in order to stabilize the lubricant application. Since the configuration is basically the same as that of the conventional technique, the amount of the lubricant 141 applied to the photosensitive drum 110 varies depending on whether the brush roller 142 is new or old (slack) and the lubricant 141 is new / old. Similar to the prior art, when the brush roller 142 is new and has no settling, etc., the scraping ability of the lubricant 141 by the brush roller 142 is large, and the amount of lubricant applied from the brush roller 142 to the photosensitive drum 110 is as follows. (Brush / lubricant etc. is used to some extent and the amount of applied lubricant is stable). In such a case, in this embodiment, by increasing the alternating peak-to-peak voltage (Vp-p) applied to the charging roller 121 and increasing the charging current, the amount of lubricant consumed by destruction is increased by the charging current. The excessive application amount of the lubricant 141 is destroyed and consumed. Accordingly, it is possible to prevent excessive lubricant 141 on the photosensitive drum 110 from adhering to the charging roller 121, and to suppress the contamination of the charging roller 121, thereby preventing the occurrence of problems such as charging failure and streak image due to the contamination. The amount of lubricant remaining on the photosensitive drum 110 after passing through the position of the charging unit 120 can be properly maintained. For example, in the initial stage of use of the brush roller 142, when the lubricant application amount is about 1.5 times that when the lubricant application is stable, the charging AC peak-to-peak voltage is 1.9 kVp-p when the lubricant application is stable. The charging AC peak-to-peak voltage is increased to 2.1 kVp-p (FIGS. 4A and 4D).

  Further, when the brush roller 142 is used for a long period of time, the brush roller 142 is drooping, and the amount of the lubricant 141 applied is smaller than when the lubricant application is stable. In this case, in this embodiment, the AC peak-to-peak voltage (Vp-p) applied to the charging roller 121 is reduced, the charging current is reduced, and the attacking action of the charging current on the photosensitive drum 110 is reduced. The necessary amount of lubricant 141 that is destroyed and consumed for protecting the photosensitive drum 110 is reduced. As a result, it is possible to prevent the surface of the photosensitive drum 110 from being destroyed due to insufficient application of the lubricant, resulting in filming of the photosensitive member, and poor cleaning due to insufficient lubrication. For example, when the life of the brush roller 142 is approaching and the amount of lubricant applied is about 0.7 times that when the lubricant application is stable, the charging AC peak-to-peak voltage is 1.9 kVp-p when the lubricant application is stable. The charging AC peak-to-peak voltage is reduced to 1.7 kVp-p (FIGS. 4C and 4D).

  In this embodiment, the image forming unit 100 is a process cartridge in which the photosensitive drum 110, the charging unit 120, the developing device 130, the lubricant applying device 140, and the cleaning device 150 are integrated. Replace the image unit 100. By integrating various means relating to image formation into a unit, the setability and maintainability are improved, and further, the position accuracy of the photoconductor is also improved. Although not shown in the figure, a detection means for detecting whether or not the image forming unit 100 as a process cartridge is new is provided, the cumulative number of rotations of the photosensitive drum 110 is recorded, and the usage time of the process cartridge is recorded. Thereby, the usage time of the brush roller 142 is detected, and the charging AC peak-to-peak voltage is controlled as described above. These charging AC peak-to-peak voltages can be changed by changing the control value of the charging AC peak voltage directly in the case of constant voltage control due to the difference in the control method for controlling the AC applied voltage to the charging means 120. In the case of constant current control, this can be achieved by changing the control value of the charging current. Moreover, you may implement these control value changes in steps (FIG. 4E).

<Embodiment 2>
5A to 5C show Embodiment 2 of the present invention. The present embodiment has substantially the same configuration as that of the first embodiment, but differs in the configuration of a process cartridge that is used by replacing the lubricant 141 because the life of the lubricant 141 is short.

  In this configuration, when only the lubricant 141 is replaced and renewed while the brush roller 142 is used, the contact area between the brush roller 142 to which the lubricant is applied and the lubricant 141 is reduced, and the brush roller 142 is lubricated. The ability to scrape off the agent 141 is reduced, and the amount of lubricant applied to the photosensitive drum 110 is reduced. In such a case, in this embodiment, the AC peak-to-peak voltage (Vp-p) applied to the charging roller 121 is reduced, the charging current is reduced, and the photosensitive body attack action of the charging current is reduced. Accordingly, the necessary amount of the lubricant 141 that is destroyed and consumed for protecting the photosensitive drum 110 is reduced, and the surface destruction of the photosensitive drum 110 is progressed due to insufficient application of the lubricant. Can be prevented. In the second embodiment, a detection mechanism for detecting a new state of the lubricant 141 is mounted to detect that the lubricant 141 is new.

  As the lubricant 141 used in each embodiment described above, a lubricant containing a fatty acid metal salt (A) and an inorganic lubricant (B) is preferable. The fatty acid metal salt is prevented from being destroyed by the charging current, and the surface of the photosensitive drum 110 is prevented from being destroyed. At the same time, the inorganic lubricant that is not destroyed by the charging current has a lubricating action (the lubricant is composed only of the fatty acid metal salt). Therefore, the cleaning of the surface of the photosensitive drum 110 can be better maintained.

  Examples of the fatty acid metal salt (A) include barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate, Zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, palmitate Aluminum, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricinoleate, cadmium ricinoleate and mixtures thereof Some, but not limited to these. Moreover, you may use these in mixture. In the practice of the present invention, zinc stearate is considered to be most preferable because it is particularly excellent in film formability on an image carrier. In addition, the fatty acid metal salt is zinc stearate to improve the film-forming property on the photoreceptor, and the lubricity and protection of the photoreceptor are excellent. In addition, when the inorganic lubricant is boron nitride, the lubricity is excellent. It becomes.

  In the present application, the inorganic lubricant (B) refers to an inorganic compound that cleaves and lubricates itself or causes internal slipping. Specific examples of substances include talc, mica, boron nitride, Examples include molybdenum sulfide, tungsten disulfide, kaolin, smectite, hydrotalcite compound, calcium fluoride, graphite, plate-like alumina, sericite, and synthetic mica, but are not limited thereto. Boron nitride has hexagonal mesh surfaces with tightly intermingled atoms overlapping at wide intervals, and the force acting between the layers is only a weak van der Waals force. It is considered preferable. That is, when the lubricant contains an inorganic lubricant in the fatty acid metal salt, the fatty acid metal salt prevents the surface of the photoreceptor from being destroyed by the charging current, and at the same time, lubrication is performed by the inorganic lubricant that is not destroyed by the charging current. Since the action is maintained in a better state (than when the lubricant is a fatty acid metal salt), it is possible to maintain the photoreceptor cleaning better. These inorganic lubricants may be subjected to surface treatment as necessary for imparting hydrophobicity or the like.

  As described above, even when the lubricant application brush is new and the amount of lubricant application is large, the lubricant applied on the photoconductor can be further increased by increasing the charging AC peak voltage more than usual. It is possible to prevent the excessive lubricant on the photosensitive member from adhering to the charging member, which causes problems such as contamination of the charging roller due to excessive application of the lubricant, poor charging due to contamination, and vertical stripe images. Occurrence can be prevented.

  In addition, even when the lubricant application amount is small, such as changing the lubricant only in a state where the brush and lubricant are used to some extent and the lubricant application amount is stable, the charging AC peak-to-peak voltage is made smaller than usual, By reducing the photosensitive body attacking action of the charging current, the amount of lubricant that is destroyed and consumed by the protection of the photosensitive body is reduced, and it is possible to prevent problems such as filming of the photosensitive body and defective cleaning due to insufficient application of the lubricant. .

  In addition, even when the brush roller is drunk due to long-term use and the amount of lubricant applied decreases, similarly, by reducing the charging AC peak-to-peak voltage to a lower level than usual, the AC attack effect on the photosensitive member is reduced. Further, the amount of lubricant that is destroyed and consumed by protecting the photoconductor is reduced, and problems such as photoconductor filming and poor cleaning due to insufficient application of the lubricant can be prevented.

  Furthermore, if a lubricant application mechanism is provided on the downstream side of the photoconductor cleaning means with respect to the photoconductor rotation direction, there is no excessive or insufficient supply of lubricant to the photoconductor due to the image area ratio (in photoconductor cleaning upstream application). When the image area increases, the contact area between the lubricant and the photoreceptor surface decreases, resulting in insufficient application of the lubricant), and stable application of the lubricant becomes possible.

  If a contact charging roller is mounted as a charging device, the generation of ozone is reduced. If a charging roller facing the photoconductor with a small gap is mounted as a charging device, dirt such as toner from the photoconductor hardly adheres to the surface of the charging roller, so that the charging roller can be prevented from becoming dirty and the life can be extended.

  If a polymerized toner having a uniform shape is used, the development characteristics and transferability are improved, and the image quality is improved.

1: Image forming apparatus 10: Paper feed unit 11, 12: Paper feed cassette 20: Image forming unit 30: Transfer unit 31, 32, 33: Roller 34: Intermediate transfer belt 35: Secondary transfer roller 37: Belt cleaning device 40 : Optical writing unit 50: Fixing device 60: Transport paths 70Y, 70M, 70C, 70K: Toner bottles 100Y, 100M, 100C, 100K: Image forming units 110Y, 110M, 110C, 110K: Photosensitive drum 120: Charging means 121 : Charging roller 122: cleaning roller 130: developing device 131: developing roller 132, 133: stirring roller 140: lubricant applying device 141: lubricant 142: brush roller 150: cleaning device 153: waste toner conveying member 160: applying lubricant Blade 161: Lubricant application blade 162: Support member

JP 2009-128842 A JP 2006-113499 A JP 2010-008998 A

Claims (10)

In an electrophotographic image forming apparatus equipped with a mechanism for applying a lubricant to an image carrier such as a photosensitive drum, and applying an AC voltage to a charging means for charging the image carrier.
An image forming apparatus, wherein an alternating peak-to-peak voltage (Vp-p) applied to the charging unit is changed in accordance with fluctuations in the consumption amount of the lubricant.   2. The image forming apparatus according to claim 1, wherein when the amount of applied lubricant is larger than when the amount of applied lubricant is stable, the AC peak voltage (Vp-p) applied to the charging means is increased. apparatus.   2. The image forming apparatus according to claim 1, wherein when the lubricant application amount is smaller than that when the lubricant application amount is stable, the AC peak-to-peak voltage (Vp-p) applied to the charging unit is reduced. apparatus.   2. The image forming apparatus according to claim 1, wherein the mechanism for applying the lubricant is a lubricant applying mechanism for scraping a stick-shaped solid lubricant with a brush roller and applying the lubricant to the surface of the image carrier, and the initial use of the brush roller. And an AC peak-to-peak voltage (Vp-p) applied to the charging means is increased.   2. The image forming apparatus according to claim 1, wherein the mechanism for applying the lubricant is a lubricant application mechanism for scraping off a rod-shaped solid lubricant with a brush roller and applying the same to the surface of the image carrier, and the initial use of the lubricant. And an AC peak-to-peak voltage (Vp-p) applied to the charging means is reduced.   2. The image forming apparatus according to claim 1, wherein the lubricant application mechanism is a lubricant application mechanism that scrapes off a rod-shaped solid lubricant with a brush roller and applies the lubricant to the surface of the image carrier, and the usage time of the brush roller. Accordingly, an AC peak-to-peak voltage (Vp-p) applied to the charging unit is reduced.   7. The image forming apparatus according to claim 1, wherein a mechanism for applying a lubricant to the image carrier is mounted downstream of a cleaning device that cleans the image carrier with respect to the rotation direction of the image carrier. An image forming apparatus.   8. The image forming apparatus according to claim 1, wherein a contact charging roller is mounted as the charging unit.   9. The image forming apparatus according to claim 8, wherein the charging roller faces the image carrier with a minute gap. 10. The image forming apparatus according to claim 1, wherein the image carrier, the charging unit, the image carrier cleaning device, and the latent image on the image carrier are developed as an image forming unit. An image forming apparatus comprising a process cartridge including at least one of developing devices.