JP2009042433A - Image forming apparatus, layer thickness detecting method, and layer thickness detecting program - Google Patents

Image forming apparatus, layer thickness detecting method, and layer thickness detecting program Download PDF

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JP2009042433A
JP2009042433A JP2007206274A JP2007206274A JP2009042433A JP 2009042433 A JP2009042433 A JP 2009042433A JP 2007206274 A JP2007206274 A JP 2007206274A JP 2007206274 A JP2007206274 A JP 2007206274A JP 2009042433 A JP2009042433 A JP 2009042433A
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charge amount
coating layer
layer
image carrier
initial value
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Hideki Moriya
秀樹 守屋
Chikao Ikeda
周穂 池田
Hidehiko Yamaguchi
英彦 山口
Masao Omori
雅夫 大森
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Fujifilm Business Innovation Corp
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Fuji Xerox Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To easily detect the layer thickness of the covering layer of a body to be charged having a plurality of covering layers whose dielectric constants are different. <P>SOLUTION: A control unit 62 detects an initial value of the saturated charge amount Q of an image carrier 22 through a current detecting section 88, calculates a reciprocal A0 of the initial value of the detected saturated charge amount and then, assumes that the dielectric constant of a protective layer 98 is equal to the dielectric constant of a charge transport layer 96, without changing the layer thickness initial value of the protective layer 98, to calculate the reciprocal A1 of the assumed initial value of the saturated charge amount of the image carrier 22 and determines that the image carrier 22 is used up, when the reciprocal of the saturated charge amount of the image carrier 22 detected after that is nearly equal to a predetermined value C showing the service life of the image carrier 22 (a value corresponding to the layer thickness c of the charge transport layer 96 used for determining that the image carrier 22 is used up). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、画像形成装置、層厚検出方法及び層厚検出プログラムに関するものである。   The present invention relates to an image forming apparatus, a layer thickness detection method, and a layer thickness detection program.

特許文献１は、電極部材に異なる電圧を印加して得られたＶ−Ｉ特性に基づいて、被帯電体の厚みを検知する画像形成装置を開示する。   Patent Document 1 discloses an image forming apparatus that detects the thickness of an object to be charged based on VI characteristics obtained by applying different voltages to electrode members.

特許第３０６４６４３号Japanese Patent No. 3064643

本発明は、誘電率が異なる複数の被覆層を具備する被帯電体の被覆層の層厚を容易に検出することができる画像形成装置、層厚検出方法及び層厚検出プログラムを提供することを目的とする。   The present invention provides an image forming apparatus, a layer thickness detection method, and a layer thickness detection program capable of easily detecting the layer thickness of a coating layer of an object to be charged having a plurality of coating layers having different dielectric constants. Objective.

上記目的を達成するため、請求項１に係る本発明は、誘電率が所定値である第１の被覆層と、この第１の被覆層よりも誘電率が大きく、前記第１の被覆層をさらに被覆する第２の被覆層とを具備する像保持体と、この像保持体に接触又は近接して該像保持体を帯電させる帯電部材と、この帯電部材により帯電させられる前記像保持体の飽和電荷量を検出する飽和電荷量検出手段と、この飽和電荷量検出手段が検出する飽和電荷量に基づいて、前記第２の被覆層の層厚初期値を変えることなく、前記第２の被覆層の誘電率が前記第１の被覆層の誘電率と等しいと仮定した場合の飽和電荷量の仮定初期値を算出する仮定初期値算出手段と、この仮定初期値算出手段が算出する飽和電荷量の仮定初期値と前記飽和電荷量検出手段が検出する飽和電荷量との相対関係に基づいて、前記第１の被覆層の層厚を算出する層厚算出手段とを有する画像形成装置である。   In order to achieve the above object, the present invention according to claim 1 includes a first coating layer having a predetermined dielectric constant, a dielectric constant larger than that of the first coating layer, and the first coating layer. Further, an image carrier comprising a second coating layer for coating, a charging member for charging the image carrier in contact with or in proximity to the image carrier, and the image carrier charged by the charging member. Based on the saturation charge amount detecting means for detecting the saturation charge amount and the saturation charge amount detected by the saturation charge amount detection means, without changing the initial layer thickness of the second coating layer, the second coating An assumed initial value calculating means for calculating an assumed initial value of a saturated charge amount when it is assumed that the dielectric constant of the layer is equal to the dielectric constant of the first covering layer; and the saturated charge amount calculated by the assumed initial value calculating means Assumed initial value and saturation charge detected by the saturation charge amount detection means Based on the relative relationship between an image forming apparatus having a layer thickness calculating means for calculating the thickness of the first coating layer.

請求項２に係る本発明は、前記仮定初期値算出手段が、前記第１の被覆層と前記第２の被覆層との層厚比及び誘電率比に基づいて、飽和電荷量の仮定初期値を算出する請求項１記載の画像形成装置である。   According to a second aspect of the present invention, the assumed initial value calculating means is configured to assume an assumed initial value of the saturation charge amount based on a layer thickness ratio and a dielectric constant ratio between the first coating layer and the second coating layer. The image forming apparatus according to claim 1, wherein

請求項３に係る本発明は、前記像保持体の動作量を検出する動作量検出手段と、前記飽和電荷量検出手段が飽和電荷量を検出する時機を制御する制御手段とをさらに有し、前記制御手段は、前記動作量検出手段が検出する動作量に基づいて、前記飽和電荷量検出手段が飽和電荷量の検出を再開するよう制御する請求項１又は２記載の画像形成装置である。   The present invention according to claim 3 further includes an operation amount detection means for detecting an operation amount of the image carrier, and a control means for controlling the timing when the saturation charge amount detection means detects the saturation charge amount, 3. The image forming apparatus according to claim 1, wherein the control unit controls the saturation charge amount detection unit to resume detection of the saturation charge amount based on the operation amount detected by the operation amount detection unit.

請求項４に係る本発明は、前記制御手段が、前記飽和電荷量検出手段が検出する飽和電荷量の検出結果及び検出精度に基づいて、前記飽和電荷量検出手段が飽和電荷量を検出する時機の間隔を制御する請求項３記載の画像形成装置である。   According to a fourth aspect of the present invention, when the control unit detects the saturation charge amount based on a detection result and detection accuracy of the saturation charge amount detected by the saturation charge amount detection unit. The image forming apparatus according to claim 3, wherein the interval is controlled.

請求項５に係る本発明は、前記層厚算出手段が算出する前記第１の被覆層の層厚に基づいて、前記像保持体の寿命を判定する寿命判定手段をさらに有する請求項１乃至４いずれか記載の画像形成装置である。   According to a fifth aspect of the present invention, there is provided a life judging means for judging a life of the image carrier based on a layer thickness of the first covering layer calculated by the layer thickness calculating means. Any one of the image forming apparatuses.

請求項６に係る本発明は、誘電率が所定値である第１の被覆層と、この第１の被覆層よりも誘電率が大きく、第１の被覆層をさらに被覆する第２の被覆層とを具備する被帯電体の飽和電荷量を検出し、第２の被覆層の層厚初期値を変えることなく、第２の被覆層の誘電率が第１の被覆層の誘電率と等しいと仮定して、検出した飽和電荷量に基づく飽和電荷量の仮定初期値を算出し、算出した飽和電荷量の仮定初期値とその後の被帯電体の飽和電荷量との相対関係に基づいて、第１の被覆層の層厚を算出することにより検出する層厚検出方法である。   According to a sixth aspect of the present invention, there is provided a first coating layer having a predetermined dielectric constant, and a second coating layer having a dielectric constant larger than that of the first coating layer and further covering the first coating layer. And the dielectric constant of the second coating layer is equal to the dielectric constant of the first coating layer without changing the initial value of the thickness of the second coating layer. Assuming that the assumed initial value of the saturated charge amount based on the detected saturated charge amount is calculated, and based on the relative relationship between the calculated assumed initial value of the saturated charge amount and the saturated charge amount of the subsequent charged object, This is a layer thickness detection method in which detection is performed by calculating the layer thickness of one coating layer.

請求項７に係る本発明は、誘電率が所定値である第１の被覆層と、この第１の被覆層よりも誘電率が大きく、第１の被覆層をさらに被覆する第２の被覆層とを具備する被帯電体の飽和電荷量を検出するステップと、第２の被覆層の層厚初期値を変えることなく、第２の被覆層の誘電率が第１の被覆層の誘電率と等しいと仮定して、検出した飽和電荷量に基づく飽和電荷量の仮定初期値を算出するステップと、算出した飽和電荷量の仮定初期値とその後の被帯電体の飽和電荷量との相対関係に基づいて、第１の被覆層の層厚を算出することにより検出するステップとをコンピュータに実行させる被帯電体の層厚検出プログラムである。   The present invention according to claim 7 includes a first coating layer having a predetermined dielectric constant, and a second coating layer having a dielectric constant larger than that of the first coating layer and further covering the first coating layer. And detecting the saturation charge amount of the member to be charged, and without changing the initial thickness of the second coating layer, the dielectric constant of the second coating layer is the dielectric constant of the first coating layer. Assuming that they are equal, a step of calculating an assumed initial value of the saturated charge amount based on the detected saturated charge amount, and a relative relationship between the assumed initial value of the calculated saturated charge amount and the subsequent saturated charge amount of the object to be charged And a step of detecting the layer thickness of the first coating layer based on the computer program.

請求項１に係る本発明によれば、本構成を有していない場合に比較して、誘電率が異なる複数の被覆層を具備する像保持体の被覆層の層厚を容易に検出することができる。   According to the first aspect of the present invention, the layer thickness of the coating layer of the image carrier having a plurality of coating layers having different dielectric constants can be easily detected as compared with the case where the present configuration is not provided. Can do.

請求項２に係る本発明によれば、請求項１に係る本発明の効果に加えて、像保持体の飽和電荷量の仮定初期値を容易に算出することができる。   According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the assumed initial value of the saturation charge amount of the image carrier can be easily calculated.

請求項３に係る本発明によれば、請求項１又は２に係る本発明の効果に加えて、像保持体の交換が不要な時期に第１の被覆層の層厚を算出することを防止することができる。   According to the third aspect of the present invention, in addition to the effect of the present invention according to the first or second aspect, it is possible to prevent the thickness of the first covering layer from being calculated at a time when replacement of the image carrier is unnecessary. can do.

請求項４に係る本発明によれば、請求項３に係る本発明の効果に加えて、第１の被覆層の層厚を効率的に精度よく算出することができる。   According to the present invention of claim 4, in addition to the effect of the present invention of claim 3, the layer thickness of the first coating layer can be calculated efficiently and accurately.

請求項５に係る本発明によれば、請求項１乃至４いずれかに係る本発明の効果に加えて、像保持体の寿命を容易に判定することができる。   According to the fifth aspect of the present invention, in addition to the effect of the present invention according to any one of the first to fourth aspects, the lifetime of the image carrier can be easily determined.

請求項６に係る本発明によれば、本構成を有していない場合に比較して、誘電率が異なる複数の被覆層を具備する被帯電体の被覆層の層厚を容易に検出することができる。   According to the sixth aspect of the present invention, it is possible to easily detect the layer thickness of the coating layer of the member to be charged having a plurality of coating layers having different dielectric constants, compared to the case where the present configuration is not provided. Can do.

請求項７に係る本発明によれば、本構成を有していない場合に比較して、誘電率が異なる複数の被覆層を具備する被帯電体の被覆層の層厚を容易に検出することができる。   According to the present invention of claim 7, it is possible to easily detect the layer thickness of the coating layer of the object to be charged that includes a plurality of coating layers having different dielectric constants, compared to the case where the present configuration is not provided. Can do.

次に本発明の実施形態を図面に基づいて説明する。
図１及び図２において、本発明の実施形態に係る画像形成装置１０の概要が示されている。画像形成装置１０は、画像形成部１２と、原稿読取装置１４とを有する。画像形成部１２は、例えばゼログラフィ方式のもので、用紙などの記録媒体が積載された例えば４段の給紙トレイ１６ａ，１６ｂ，１６ｃ，１６ｄ及び手差しトレイ１８とを有し、これらトレイ１６ａ〜１６ｄ、１８から記録媒体搬送路２０に供給された記録媒体に画像を形成するようになっている。 Next, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming unit 12 and a document reading device 14. The image forming unit 12 is of a xerographic type, for example, and has, for example, four stages of paper feed trays 16a, 16b, 16c, 16d on which recording media such as paper are stacked, and a manual feed tray 18, and these trays 16a to 16a. An image is formed on the recording medium supplied to the recording medium conveyance path 20 from 16d and 18.

即ち、画像形成部１２は、例えば円筒状の回転する像保持体２２と、この像保持体２２を一様に接触帯電する例えば帯電ロールからなる帯電部材２４と、この帯電部材２４により一様に帯電された像保持体２２に静電潜像を形成する露光装置（光書込み装置）２６と、この露光装置２６により形成された像保持体２２上の潜像を現像剤で可視化する現像装置２８と、この現像装置２８により形成された現像剤像を記録媒体に転写する転写装置３０と、像保持体２２に残った現像剤をクリーニングするクリーナ３２とを有する。   In other words, the image forming unit 12 includes, for example, a cylindrical rotating image holding body 22, a charging member 24 made of, for example, a charging roll that uniformly charges the image holding body 22, and the charging member 24. An exposure device (optical writing device) 26 that forms an electrostatic latent image on the charged image carrier 22 and a developing device 28 that visualizes the latent image on the image carrier 22 formed by the exposure device 26 with a developer. And a transfer device 30 that transfers the developer image formed by the developing device 28 to a recording medium, and a cleaner 32 that cleans the developer remaining on the image carrier 22.

帯電部材２４は、例えばゴムなどの弾性を有する部材を表面に有し、像保持体２２に接触して回転する。露光装置２６は、レーザ走査方式のもので、例えば原稿読取装置１４で読み取った原稿の画像をレーザのオンオフ信号に変えて出力する。転写装置３０は例えば転写ロールから構成され、この転写装置３０により現像剤像が転写された記録媒体が定着装置３４に送られ、この定着装置３４により現像剤像が記録媒体に定着される。現像剤像が定着された記録媒体は、排出トレイ３６に排出される。   The charging member 24 has a member having elasticity, such as rubber, on the surface thereof, and rotates in contact with the image carrier 22. The exposure device 26 is of a laser scanning type and outputs, for example, an image of a document read by the document reading device 14 instead of a laser on / off signal. The transfer device 30 is composed of, for example, a transfer roll, and the recording medium onto which the developer image has been transferred by the transfer device 30 is sent to the fixing device 34, and the developer image is fixed to the recording medium by the fixing device 34. The recording medium on which the developer image is fixed is discharged to the discharge tray 36.

記録媒体搬送路２０には、複数の記録媒体搬送ロール３８が設けられている。この記録媒体搬送ロール３８の一つとして、転写装置３０上流側近傍には、レジストロール４０が配置されている。このレジストロール４０は、供給された記録媒体を一時停止させ、像保持体２２に潜像が形成されるタイミングと同期して記録媒体を転写装置３０に供給するように制御される。   A plurality of recording medium conveying rolls 38 are provided in the recording medium conveying path 20. As one of the recording medium transport rolls 38, a registration roll 40 is disposed in the vicinity of the upstream side of the transfer device 30. The registration roll 40 is controlled so as to temporarily stop the supplied recording medium and supply the recording medium to the transfer device 30 in synchronization with the timing at which the latent image is formed on the image holding member 22.

原稿読取装置１４は、原稿を光学的に読み取る光学系４２と、自動原稿送り装置４４とを有する。
光学系４２は、自動原稿送り装置４４により送られた原稿を流し読みする機能と、反射ミラー等を走査して原稿台ガラス５４上に載置された原稿を読み取る機能とを備えている。 The document reading device 14 includes an optical system 42 that optically reads a document and an automatic document feeder 44.
The optical system 42 has a function of flowing and reading a document sent by the automatic document feeder 44 and a function of reading a document placed on the document table glass 54 by scanning a reflection mirror or the like.

自動原稿送り装置４４は、多数の原稿が載置される原稿載置台５６と、原稿を搬送する原稿搬送路５８と、画像を読み取った後の原稿が排出される排出台６０とを有する。   The automatic document feeder 44 includes a document placement table 56 on which a large number of documents are placed, a document conveyance path 58 that conveys the document, and a discharge table 60 that ejects the document after the image is read.

また、画像形成装置１０は、制御ユット６２、表示装置及びキーボードなどを含むユーザインタフェース装置（ＵＩ装置）６４、ＨＤＤ・ＣＤ装置などの記憶装置６６及び通信装置６８などを有する。制御ユニット６２は、ＣＰＵ７０及びメモリ７２などを含み、画像形成装置１０を構成する各部を制御するようにされている。
このように、画像形成装置１０は、コンピュータとしての機能を含み、記憶媒体７４又は通信装置６８を介して受け入れたプログラムを実行することにより、印刷などの処理を行う。 The image forming apparatus 10 includes a control unit 62, a user interface device (UI device) 64 including a display device and a keyboard, a storage device 66 such as an HDD / CD device, a communication device 68, and the like. The control unit 62 includes a CPU 70, a memory 72, and the like, and controls each part constituting the image forming apparatus 10.
As described above, the image forming apparatus 10 includes a function as a computer, and performs processing such as printing by executing the program received via the storage medium 74 or the communication device 68.

次に、像保持体２２、帯電部材２４及びその周辺について詳述する。
図３は、像保持体２２、帯電部材２４及びその周辺の構成の詳細を示す模式図である。帯電部材２４には、電源部８２が接続されている。電源部８２は、交流電源８４及び直流電源８６を有し、制御ユニット６２の制御に応じて、所定の直流電圧Ｖｄｃに交流電圧Ｖａｃを重畳した電圧を帯電部材２４に印加する。例えば、電源部８２は、交流電源８４が１０００Ｈｚの周波数でピーク間電圧Ｖｐｐが８００〜２５００Ｖ程度の交流電圧を帯電部材２４に対して印加し、直流電源８６が−７５０Ｖ程度の直流電圧Ｖｄｃを帯電部材２４に対して印加して、所定の電流を帯電部材２４に供給するようにされている。電流検出部８８は、電源部８２が帯電部材２４に対して流す電流を検出し、制御ユニット６２に対して出力する。 Next, the image carrier 22, the charging member 24, and the periphery thereof will be described in detail.
FIG. 3 is a schematic diagram showing details of the configuration of the image carrier 22, the charging member 24, and the periphery thereof. A power supply unit 82 is connected to the charging member 24. The power supply unit 82 includes an AC power supply 84 and a DC power supply 86, and applies a voltage obtained by superimposing the AC voltage Vac on the predetermined DC voltage Vdc to the charging member 24 in accordance with the control of the control unit 62. For example, in the power supply unit 82, the AC power supply 84 applies an AC voltage with a frequency of 1000 Hz and a peak-to-peak voltage Vpp of about 800 to 2500 V to the charging member 24, and the DC power supply 86 charges a DC voltage Vdc of about −750 V. It is applied to the member 24 to supply a predetermined current to the charging member 24. The current detection unit 88 detects a current that the power supply unit 82 flows to the charging member 24 and outputs the detected current to the control unit 62.

像保持体２２は、例えば接地されたアルミニウムなどからなる円筒状の導電性支持体９０と、この導電性支持体９０の外面を覆う感光層９２とを有し、例えば帯電部材２４が接触する軸方向の長さが３００ｍｍにされている。感光層９２は、図４に示すように、例えば電荷発生層９４、電荷輸送層（ＣＴ層）９６及び保護層（ＯＣ層）９８から構成される。電荷発生層９４は、電荷キャリア生成材料を含んで導電性支持体９０を被覆している。電荷輸送層９６は、電荷キャリア輸送材料を含む所定の誘電率の部材からなり、層厚が所定値に設定され、電荷発生層９４の外側に積層されている。保護層９８は、誘電率が電荷輸送層９６よりも大きい部材からなり、層厚が所定値に設定され、電荷輸送層９６の外側に積層されている。また、保護層９８は、電荷輸送層９６よりも硬度が高くされている。   The image carrier 22 includes a cylindrical conductive support 90 made of, for example, grounded aluminum, and a photosensitive layer 92 that covers the outer surface of the conductive support 90. The length in the direction is 300 mm. As shown in FIG. 4, the photosensitive layer 92 includes, for example, a charge generation layer 94, a charge transport layer (CT layer) 96, and a protective layer (OC layer) 98. The charge generation layer 94 covers the conductive support 90 including a charge carrier generating material. The charge transport layer 96 is made of a member having a predetermined dielectric constant containing a charge carrier transport material, has a layer thickness set to a predetermined value, and is stacked outside the charge generation layer 94. The protective layer 98 is made of a member having a dielectric constant larger than that of the charge transport layer 96, has a layer thickness set to a predetermined value, and is laminated outside the charge transport layer 96. Further, the protective layer 98 has a higher hardness than the charge transport layer 96.

図５は、電流検出部８８が検出する直流電流値と像保持体２２の電位との関係を示すグラフである。ここで、電源部８２は像保持体２２を帯電させるために帯電部材２４に対して交流電圧と直流電圧とを印加しており、直流電源８６が帯電部材２４に対して印加する直流電圧が−７５０Ｖとなっている。帯電部材２４に−７５０Ｖの直流電圧が印加され、像保持体２２が１回転すると、像保持体２２は約−７２０Ｖに帯電し、制御ユニット６２は電流検出部８８が検出する帯電電流とリーク電流とを含む直流電流値に応じて電荷量Ｑ１を算出する。像保持体２２は１回転しても帯電電荷量が飽和していない。   FIG. 5 is a graph showing the relationship between the DC current value detected by the current detector 88 and the potential of the image carrier 22. Here, the power source unit 82 applies an AC voltage and a DC voltage to the charging member 24 in order to charge the image carrier 22, and the DC voltage applied to the charging member 24 by the DC power source 86 is − It is 750V. When a DC voltage of −750 V is applied to the charging member 24 and the image carrier 22 rotates once, the image carrier 22 is charged to about −720 V, and the control unit 62 detects the charging current and leakage current detected by the current detector 88. The charge amount Q1 is calculated according to a direct current value including The charge amount of the image carrier 22 is not saturated even after one rotation.

像保持体２２が２回転すると、像保持体２２は約−７４０Ｖに帯電し、制御ユニット６２は電流検出部８８が検出する帯電電流とリーク電流とを含む直流電流値に応じて電荷量Ｑ２を算出する。像保持体２２は２回転しても帯電電荷量が飽和していない。像保持体２２が３回転すると、像保持体２２は約−７５０Ｖに帯電し、制御ユニット６２は電流検出部８８が検出する帯電電流とリーク電流とを含む直流電流値に応じて電荷量Ｑ３を算出する。像保持体２２は３回転すると帯電電荷量が飽和している。像保持体２２が４回転すると、像保持体２２の帯電電荷量が飽和しているので、制御ユニット６２は電流検出部８８が検出するリーク電流のみからなる直流電流値に応じて電荷量Ｑ４を算出する。なお、電流検出部８８が検出するリーク電流には、電源部８２が印加する電圧値に応じて変化するリーク電流と、電源部８２が印加する電圧値によらず流れるリーク電流とが含まれている。   When the image carrier 22 rotates twice, the image carrier 22 is charged to about −740 V, and the control unit 62 sets the charge amount Q2 according to the direct current value including the charging current and the leakage current detected by the current detector 88. calculate. Even when the image carrier 22 is rotated twice, the charged charge amount is not saturated. When the image carrier 22 rotates three times, the image carrier 22 is charged to about −750 V, and the control unit 62 sets the charge amount Q3 according to the DC current value including the charging current and the leakage current detected by the current detector 88. calculate. When the image carrier 22 rotates three times, the charge amount is saturated. When the image carrier 22 rotates four times, the charge amount of the image carrier 22 is saturated. Therefore, the control unit 62 sets the charge amount Q4 according to the DC current value consisting only of the leakage current detected by the current detector 88. calculate. Note that the leakage current detected by the current detection unit 88 includes a leakage current that varies depending on the voltage value applied by the power supply unit 82 and a leakage current that flows regardless of the voltage value applied by the power supply unit 82. Yes.

像保持体２２が３回転するまでに制御ユニット６２が算出した電荷量Ｑ１，Ｑ２，Ｑ３には、それぞれリーク電流に対応する電荷量Ｑ４が含まれている。そこで、制御ユニット６２は、像保持体２２の飽和電荷量Ｑを下式１により算出することにより、検出するようにされている。   The charge amounts Q1, Q2, and Q3 calculated by the control unit 62 until the image carrier 22 rotates three times each include a charge amount Q4 corresponding to the leakage current. Therefore, the control unit 62 is configured to detect the saturation charge amount Q of the image carrier 22 by calculating the following equation 1.

飽和電荷量Ｑ＝Ｑ１＋Ｑ２＋Ｑ３−Ｑ４×３ ・・・（１）   Saturation charge Q = Q1 + Q2 + Q3-Q4 × 3 (1)

像保持体２２は、上述したように円筒状の部材であり、帯電部材２４が接触することによって外面側から摩耗し、感光層９２の総層厚が摩耗によって減少すると、飽和電荷量Ｑが増大する。
そこで、制御ユニット６２は、像保持体２２の飽和電荷量Ｑを検出し、感光層９２の総層厚を算出することにより検出して、像保持体２２の寿命を判定するようにされている。 As described above, the image carrier 22 is a cylindrical member, and wears from the outer surface side when the charging member 24 comes into contact. When the total layer thickness of the photosensitive layer 92 decreases due to wear, the saturation charge amount Q increases. To do.
Therefore, the control unit 62 detects the saturation charge amount Q of the image carrier 22 and calculates the total thickness of the photosensitive layer 92 to determine the lifetime of the image carrier 22. .

図６は、像保持体２２の動作量に応じて摩耗する感光層９２の総層厚の変化と、像保持体２２の飽和電荷量の変化との関係を示すグラフである。なお、像保持体２２の飽和電荷量の変化は、図６において、縦軸に像保持体２２の飽和電荷量の逆数をとることによって示されている。   FIG. 6 is a graph showing the relationship between the change in the total layer thickness of the photosensitive layer 92 that is worn according to the operation amount of the image carrier 22 and the change in the saturation charge amount of the image carrier 22. Note that the change in the saturation charge amount of the image carrier 22 is shown in FIG. 6 by taking the reciprocal of the saturation charge amount of the image carrier 22 on the vertical axis.

図６に示すように、感光層９２の総層厚の初期値をａ（仕様値：定数）とすると、像保持体２２の動作量に応じて感光層９２が摩耗し、感光層９２の総層厚がｂ０（仕様値：定数）になるまで、略保護層（ＯＣ層）９８のみが摩耗する。保護層９８が摩耗する間は、感光層９２の総層厚と像保持体２２の飽和電荷量の逆数とが比例関係にある。感光層９２の層層厚がｂ０に達すると、保護層９８は略消失しており、さらに感光層９２が動作を続けると、電荷輸送層（ＣＴ層）９６のみが摩耗する。また、電荷輸送層９６が摩耗する間も、感光層９２の総層厚と像保持体２２の飽和電荷量の逆数とが比例関係にある。ただし、上述したように、保護層９８は、誘電率が電荷輸送層９６よりも大きいので、感光層９２の総層厚に対する像保持体２２の飽和電荷量の逆数の傾きは、保護層９８が摩耗している期間よりも、電荷輸送層９６が摩耗している期間の方が大きくなっている。   As shown in FIG. 6, when the initial value of the total thickness of the photosensitive layer 92 is a (specification value: constant), the photosensitive layer 92 is worn according to the operation amount of the image carrier 22, and the total photosensitive layer 92 is Until the layer thickness reaches b0 (specification value: constant), only the protective layer (OC layer) 98 is worn. While the protective layer 98 is worn, the total thickness of the photosensitive layer 92 and the inverse of the saturation charge amount of the image carrier 22 are in a proportional relationship. When the layer thickness of the photosensitive layer 92 reaches b0, the protective layer 98 is substantially lost, and when the photosensitive layer 92 continues to operate, only the charge transport layer (CT layer) 96 is worn. While the charge transport layer 96 is worn, the total thickness of the photosensitive layer 92 and the inverse of the saturation charge amount of the image carrier 22 are in a proportional relationship. However, as described above, since the protective layer 98 has a dielectric constant larger than that of the charge transport layer 96, the slope of the reciprocal of the saturation charge amount of the image carrier 22 with respect to the total thickness of the photosensitive layer 92 is that of the protective layer 98. The period during which the charge transport layer 96 is worn out is larger than the period during which it is worn out.

制御ユニット６２は、電流検出部８８介して像保持体２２の飽和電荷量Ｑの初期値を検出し、保護層９８の層厚初期値を変えることなく、保護層９８の誘電率が電荷輸送層９６の誘電率と等しいと仮定して、像保持体２２の飽和電荷量の仮定初期値を算出し、その後に検出する像保持体２２の飽和電荷量Ｑが像保持体２２の寿命を示す所定値（像保持体２２が寿命に達したと判定されるべき電荷輸送層９６の層厚ｃに対応する値）に略一致した場合に、像保持体２２が寿命に達したと判定するようにされている。   The control unit 62 detects the initial value of the saturation charge amount Q of the image carrier 22 via the current detection unit 88, and the dielectric constant of the protective layer 98 is changed to the charge transport layer without changing the initial layer thickness of the protective layer 98. Assuming that the dielectric constant is equal to 96, an assumed initial value of the saturation charge amount of the image carrier 22 is calculated, and the saturation charge amount Q of the image carrier 22 detected thereafter indicates a predetermined lifetime indicating the life of the image carrier 22. When the value substantially corresponds to the value (the value corresponding to the layer thickness c of the charge transport layer 96 to be determined that the image carrier 22 has reached the lifetime), it is determined that the image carrier 22 has reached the lifetime. Has been.

制御ユニット６２は、図６に示したように、飽和電荷量Ｑを示す値に代えて、飽和電荷量の逆数を用いて飽和電荷量の変化を示すようにされてもよい。
例えば、制御ユニット６２は、電流検出部８８介して像保持体２２の飽和電荷量Ｑの初期値を検出し、検出した飽和電荷量の初期値の逆数Ａ０を算出した後に、保護層９８の層厚初期値を変えることなく、保護層９８の誘電率が電荷輸送層９６の誘電率と等しいと仮定して、像保持体２２の飽和電荷量の仮定初期値の逆数Ａ１を算出し、その後に検出する像保持体２２の飽和電荷量の逆数が像保持体２２の寿命を示す所定値Ｃ（像保持体２２が寿命に達したと判定されるべき電荷輸送層９６の層厚ｃに対応する値）に略一致した場合に、像保持体２２が寿命に達したと判定するようにされてもよい。 As shown in FIG. 6, the control unit 62 may be configured to indicate the change in the saturation charge amount using the reciprocal of the saturation charge amount instead of the value indicating the saturation charge amount Q.
For example, the control unit 62 detects the initial value of the saturation charge amount Q of the image carrier 22 via the current detection unit 88 and calculates the reciprocal A0 of the detected initial value of the saturation charge amount. Assuming that the dielectric constant of the protective layer 98 is equal to the dielectric constant of the charge transport layer 96 without changing the initial thickness value, an inverse number A1 of the assumed initial value of the saturation charge amount of the image carrier 22 is calculated, and thereafter The reciprocal of the saturation charge amount of the image carrier 22 to be detected corresponds to a predetermined value C indicating the life of the image carrier 22 (corresponding to the layer thickness c of the charge transport layer 96 to be determined that the image carrier 22 has reached the life. (Value) may be determined to have reached the end of its life.

像保持体２２の寿命を示す所定値Ｃは、飽和電荷量の仮定初期値の逆数Ａ１に対する相対値であり、感光層９２の総層厚が初期値ａから例えば４０％消失した場合の飽和電荷量の逆数に対応している。
また、制御ユニット６２は、像保持体２２の動作量を検出し、飽和電荷量が誤差を含んで検出されても、検出精度に応じて、飽和電荷量の逆数が所定値Ｃよりも大きい値（例えば所定値Ｂ１：電荷輸送層９６の層厚ｃよりも大きい値の層厚ｂ１に対応）になるように、像保持体２２の動作量に応じて感光層９２の摩耗量（又は総層厚）を予測し、予測結果に応じたタイミング（時機）に飽和電荷量Ｑの検出を再開するようにされてもよい。
さらに、制御ユニット６２は、電流検出部８８を介して検出した飽和電荷量Ｑの値に応じて、次に飽和電荷量Ｑを検出する時機を設定するようにされてもよい。例えば、制御ユニット６２は、検出した飽和電荷量Ｑの値が層厚ｃの値に近づくにつれて、飽和電荷量Ｑを検出する間隔を短くするようにされてもよい。 The predetermined value C indicating the lifetime of the image carrier 22 is a relative value with respect to the reciprocal A1 of the assumed initial value of the saturated charge amount, and the saturated charge when the total layer thickness of the photosensitive layer 92 disappears, for example, 40% from the initial value a. Corresponds to the inverse of the quantity.
Further, the control unit 62 detects the operation amount of the image carrier 22, and even if the saturation charge amount is detected including an error, the reciprocal of the saturation charge amount is a value larger than the predetermined value C according to the detection accuracy. The amount of wear (or total layer) of the photosensitive layer 92 according to the operation amount of the image carrier 22 so as to be (for example, a predetermined value B1: a layer thickness b1 having a value larger than the layer thickness c of the charge transport layer 96). (Thickness) may be predicted, and detection of the saturation charge amount Q may be resumed at a timing (time) according to the prediction result.
Further, the control unit 62 may set a timing for detecting the saturation charge amount Q next in accordance with the value of the saturation charge amount Q detected via the current detection unit 88. For example, the control unit 62 may shorten the interval for detecting the saturation charge amount Q as the value of the detected saturation charge amount Q approaches the value of the layer thickness c.

次に、制御ユニット６２が電荷輸送層９６の層厚を算出し、像保持体２２の寿命を判定するために行う処理の具体例について説明する。
図７は、制御ユニット６２が電荷輸送層９６の層厚を算出し、像保持体２２の寿命を判定するために実行する寿命判定プログラム１００の構成を示すプログラム構成図である。
図７に示すように、寿命判定プログラム１００は、サイクル数（動作量）検出部１０２、時機（タイミング）制御部１０４、飽和電荷量検出部１０６、仮定初期値算出部１０８、層厚算出部１１０及び寿命判定部１１２から構成される。 Next, a specific example of processing performed for the control unit 62 to calculate the layer thickness of the charge transport layer 96 and determine the lifetime of the image carrier 22 will be described.
FIG. 7 is a program configuration diagram showing a configuration of a lifetime determination program 100 executed by the control unit 62 to calculate the layer thickness of the charge transport layer 96 and determine the lifetime of the image carrier 22.
As shown in FIG. 7, the life determination program 100 includes a cycle number (operation amount) detection unit 102, a time (timing) control unit 104, a saturated charge amount detection unit 106, an assumed initial value calculation unit 108, and a layer thickness calculation unit 110. And a life determination unit 112.

サイクル数検出部１０２は、例えば像保持体２２に対する静電潜像形成回数情報（像保持体２２の回転数）を取得して、像保持体２２のサイクル数（動作量）を検出し、時機制御部１０４に対して出力する。   The cycle number detection unit 102 acquires, for example, information on the number of electrostatic latent image formations on the image carrier 22 (the number of rotations of the image carrier 22), detects the cycle number (operation amount) of the image carrier 22, and Output to the control unit 104.

時機制御部１０４は、サイクル数検出部１０２が出力する像保持体２２のサイクル数に応じて、飽和電荷量検出部１０６が飽和電荷量Ｑの初期値を検出する時機（タイミング）を制御するとともに、飽和電荷量検出部１０６が検出する飽和電荷量Ｑの検出結果、及びサイクル数検出部１０２が出力する像保持体２２のサイクル数に応じて、飽和電荷量検出部１０６が次に飽和電荷量Ｑを検出する時機（タイミング）を制御する。   The timing control unit 104 controls the timing (timing) at which the saturation charge amount detection unit 106 detects the initial value of the saturation charge amount Q according to the number of cycles of the image carrier 22 output from the cycle number detection unit 102. The saturation charge amount detection unit 106 then selects the saturation charge amount according to the detection result of the saturation charge amount Q detected by the saturation charge amount detection unit 106 and the number of cycles of the image carrier 22 output from the cycle number detection unit 102. The timing (timing) for detecting Q is controlled.

飽和電荷量検出部１０６は、時機制御部１０４の制御（設定）に応じて、電流検出部８８が検出する帯電電流とリーク電流とを含む直流電流値を受け入れ、上式１を用いて像保持体２２の飽和電荷量Ｑを算出することにより検出し、飽和電荷量Ｑの初期値を仮定初期値算出部１０８に対して出力し、その他の飽和電荷量Ｑの値を時機制御部１０４及び層厚算出部１１０に対して出力する。   The saturation charge amount detection unit 106 accepts a direct current value including a charging current and a leakage current detected by the current detection unit 88 in accordance with the control (setting) of the timing control unit 104, and holds an image using the above equation 1. The saturation charge amount Q of the body 22 is detected and detected, and the initial value of the saturation charge amount Q is output to the assumed initial value calculation unit 108, and the other saturation charge amount Q values are output to the time control unit 104 and the layer Output to the thickness calculator 110.

仮定初期値算出部１０８は、飽和電荷量検出部１０６が出力する飽和電荷量Ｑの初期値を受け入れ、例えば上述した像保持体２２の飽和電荷量の仮定初期値を算出し、層厚算出部１１０に対して出力する。
なお、仮定初期値算出部１０８は、飽和電荷量検出部１０６が出力する飽和電荷量Ｑの初期値を受け入れ、例えば上述した像保持体２２の飽和電荷量Ｑの初期値の逆数Ａ０、及び像保持体２２の飽和電荷量の仮定初期値の逆数Ａ１を算出し、層厚算出部１１０に対して出力するようにされてもよい。 The assumed initial value calculation unit 108 receives the initial value of the saturation charge amount Q output from the saturation charge amount detection unit 106, calculates, for example, the assumed initial value of the saturation charge amount of the image carrier 22 described above, and the layer thickness calculation unit. 110 for output.
The assumed initial value calculation unit 108 receives the initial value of the saturation charge amount Q output from the saturation charge amount detection unit 106, and for example, the reciprocal A0 of the initial value of the saturation charge amount Q of the image carrier 22 described above and the image. The reciprocal A1 of the assumed initial value of the saturation charge amount of the holding body 22 may be calculated and output to the layer thickness calculation unit 110.

層厚算出部１１０は、仮定初期値算出部１０８が出力する飽和電荷量の仮定初期値（又は仮定初期値の逆数Ａ１）と、飽和電荷量検出部１０６が出力する飽和電荷量Ｑとを受け入れ、飽和電荷量の仮定初期値（又は仮定初期値の逆数Ａ１）と飽和電荷量Ｑ（又は１／Ｑ）との相対関係に応じて感光層９２の総層厚を算出し、寿命判定部１１２に対して出力する。
例えば、層厚算出部１１０は、仮定初期値の逆数Ａ１と飽和電荷量Ｑの逆数１／Ｑとの相対関係に応じて感光層９２の総層厚を算出する場合、下式２による演算を行って、感光層９２の総層厚の値を算出する。 The layer thickness calculation unit 110 receives the assumed initial value of the saturated charge amount output from the assumed initial value calculation unit 108 (or the reciprocal A1 of the assumed initial value) and the saturated charge amount Q output from the saturated charge amount detection unit 106. The total thickness of the photosensitive layer 92 is calculated according to the relative relationship between the assumed initial value of the saturated charge amount (or the reciprocal A1 of the assumed initial value) and the saturated charge amount Q (or 1 / Q), and the life determination unit 112. Output for.
For example, when calculating the total layer thickness of the photosensitive layer 92 according to the relative relationship between the reciprocal number A1 of the assumed initial value and the reciprocal number 1 / Q of the saturated charge amount Q, the layer thickness calculation unit 110 performs the calculation according to the following equation 2. Then, the value of the total layer thickness of the photosensitive layer 92 is calculated.

Ａ１＝Ａ０×（ａ０×Ｒ＋ｂ０）÷（ａ０＋ｂ０） ・・・（２）
ただし、
Ａ１：仮定初期値の逆数
Ａ０：飽和電荷量Ｑの初期値の逆数
ａ０：保護層９８の層厚（仕様値：定数）
ｂ０：電荷輸送層９６の層厚（仕様値：定数）
Ｒ：誘電率比＝ε１／ε２
ε１：保護層９８の誘電率
ε２：電荷輸送層９６の誘電率 A1 = A0 × (a0 × R + b0) ÷ (a0 + b0) (2)
However,
A1: Reciprocal of assumed initial value
A0: Reciprocal of initial value of saturation charge amount Q
a0: Layer thickness of the protective layer 98 (specification value: constant)
b0: Layer thickness of the charge transport layer 96 (specification value: constant)
R: dielectric constant ratio = ε1 / ε2
ε1: dielectric constant of protective layer 98
ε2: dielectric constant of the charge transport layer 96

寿命判定部１１２は、層厚算出部１１０が出力した感光層９２の総層厚の値を受け入れ、感光層９２の総層厚が電荷輸送層９６の層厚ｂ０（仕様値：定数）以下であり、像保持体２２の寿命と判定されるべき電荷輸送層９６の層厚ｃ（判定基準値）に略一致した場合に、像保持体２２が寿命に達したと判定し、例えばＵＩ装置６４などに対して出力する。   The life determination unit 112 receives the value of the total layer thickness of the photosensitive layer 92 output from the layer thickness calculation unit 110, and the total layer thickness of the photosensitive layer 92 is equal to or less than the layer thickness b0 (specification value: constant) of the charge transport layer 96. Yes, when the thickness of the charge transport layer 96 to be determined as the lifetime of the image carrier 22 is substantially equal to the thickness c (determination reference value), it is determined that the image carrier 22 has reached the lifetime, for example, the UI device 64. Is output for

図８は、制御ユニット６２が寿命判定プログラム１００を実行して像保持体２２の寿命を判定するために行う処理例（Ｓ１０）を示すフローチャートである。
図８に示すように、ステップ１００（Ｓ１００）において、飽和電荷量検出部１０６は、時機制御部１０４の制御に応じて、飽和電荷量Ｑの初期値を検出する。 FIG. 8 is a flowchart showing a processing example (S10) performed for the control unit 62 to execute the life determination program 100 to determine the life of the image carrier 22.
As shown in FIG. 8, in step 100 (S <b> 100), the saturation charge amount detection unit 106 detects the initial value of the saturation charge amount Q in accordance with the control of the timing control unit 104.

ステップ１０２（Ｓ１０２）において、仮定初期値算出部１０８は、像保持体２２の飽和電荷量の仮定初期値（又は仮定初期値の逆数Ａ１）を算出する。   In step 102 (S102), the assumed initial value calculation unit 108 calculates an assumed initial value (or an inverse number A1 of the assumed initial value) of the saturation charge amount of the image carrier 22.

ステップ１０４（Ｓ１０４）において、サイクル数検出部１０２は、像保持体２２のサイクル数（動作量）を検出する。   In step 104 (S104), the cycle number detection unit 102 detects the cycle number (operation amount) of the image carrier 22.

ステップ１０６（Ｓ１０６）において、時機制御部１０４は、Ｓ１０４の処理で検出したサイクル数が例えば所定値に達したか否かを判定し、所定値に達した（サイクル数＝所定値）場合にはＳ１０８の処理に進み、その他の場合にはＳ１０４の処理に進む。ここで、制御ユニット６２がサイクル数と比較する所定値は、例えば電荷輸送層９６の層厚が層厚ｃよりも大きい値の層厚ｂ１であることを予測可能なサイクル数（像保持体２２の動作量）である。   In step 106 (S106), the time control unit 104 determines whether or not the number of cycles detected in the process of S104 has reached a predetermined value, for example, and if it has reached a predetermined value (number of cycles = predetermined value). The process proceeds to S108, and in other cases, the process proceeds to S104. Here, the predetermined value that the control unit 62 compares with the number of cycles is, for example, the number of cycles that can be predicted that the layer thickness b1 of the charge transport layer 96 is larger than the layer thickness c (the image carrier 22). ).

ステップ１０８（Ｓ１０８）において、時機制御部１０４は、飽和電荷量Ｑの検出時機を飽和電荷量検出部１０６に対して設定する。   In step 108 (S108), the timing control unit 104 sets the timing for detecting the saturation charge amount Q to the saturation charge amount detection unit 106.

ステップ１１０（Ｓ１１０）において、飽和電荷量検出部１０６は、時機制御部１０４による設定に応じて飽和電荷量Ｑを検出する。   In step 110 (S110), the saturation charge amount detection unit 106 detects the saturation charge amount Q according to the setting by the timing control unit 104.

ステップ１１２（Ｓ１１２）において、層厚算出部１１０は、Ｓ１０２の処理において算出された像保持体２２の飽和電荷量の仮定初期値（又は仮定初期値の逆数Ａ１）と、Ｓ１１０の処理において検出された飽和電荷量Ｑ（又は１／Ｑ）との相対関係に応じて感光層９２の総層厚を算出する。   In step 112 (S112), the layer thickness calculator 110 detects the assumed initial value (or the inverse A1 of the assumed initial value) of the saturation charge amount of the image carrier 22 calculated in the process of S102 and the process of S110. The total layer thickness of the photosensitive layer 92 is calculated according to the relative relationship with the saturated charge amount Q (or 1 / Q).

ステップ１１４（Ｓ１１４）において、寿命判定部１１２は、Ｓ１１２の処理において算出された感光層９２の総層厚が像保持体２２の寿命と判定されるべき電荷輸送層９６の層厚ｃ（判定基準値）に略一致するか否かを判定し、感光層９２の総層厚が層厚ｃに略一致する場合にはＳ１１６の処理に進み、その他の場合はＳ１０８の処理に進む。   In step 114 (S114), the lifetime determination unit 112 determines the layer thickness c of the charge transport layer 96 (determination criterion) for which the total layer thickness of the photosensitive layer 92 calculated in the processing of S112 should be determined as the lifetime of the image carrier 22. Value), if the total thickness of the photosensitive layer 92 substantially matches the layer thickness c, the process proceeds to S116, and otherwise the process proceeds to S108.

ステップ１１６（Ｓ１１６）において、寿命判定部１１２は、像保持体２２が寿命であると判定する。   In step 116 (S116), the lifetime determination unit 112 determines that the image carrier 22 has a lifetime.

本発明の実施形態に係る画像形成装置の概要を示す側面図である。1 is a side view illustrating an outline of an image forming apparatus according to an embodiment of the present invention. 本発明の実施形態に係る画像形成装置の概要を示す構成図である。1 is a configuration diagram illustrating an overview of an image forming apparatus according to an embodiment of the present invention. 像保持体、帯電部材及びその周辺の構成の詳細を示す模式図である。FIG. 2 is a schematic diagram illustrating details of an image carrier, a charging member, and the surrounding configuration. 像保持体の断面の構成を示す模式図である。It is a schematic diagram which shows the structure of the cross section of an image holding body. 電流検出部が検出する直流電流値と像保持体の電位との関係を示すグラフである。It is a graph which shows the relationship between the direct current value which an electric current detection part detects, and the electric potential of an image holding body. 像保持体の動作量に応じて摩耗する感光層の総層厚の変化と、像保持体の飽和電荷量の変化との関係を示すグラフである。6 is a graph showing a relationship between a change in the total layer thickness of a photosensitive layer worn according to an operation amount of the image carrier and a change in a saturation charge amount of the image carrier. 制御ユニットが電荷輸送層の層厚を算出し、像保持体の寿命を判定するために実行する寿命判定プログラムの構成を示すプログラム構成図である。It is a program block diagram which shows the structure of the lifetime determination program performed in order that a control unit calculates the layer thickness of an electric charge transport layer, and determines the lifetime of an image carrier. 制御ユニットが寿命判定プログラムを実行して像保持体の寿命を判定するために行う処理例（Ｓ１０）を示すフローチャートである。It is a flowchart which shows the process example (S10) performed in order that a control unit may perform the lifetime determination program and determine the lifetime of an image holding body.

１０ 画像形成装置
１２ 画像形成部
２２ 像保持体
２４ 帯電部材
６２ 制御ユニット
６４ ＵＩ装置
７０ ＣＰＵ
７２ メモリ
８２ 電源部
８４ 交流電源
８６ 直流電源
８８ 電流検出部
９０ 導電性支持体
９２ 感光層
９４ 電荷発生層
９６ 電荷輸送層
９８ 保護層
１００ 寿命判定プログラム
１０２ サイクル数検出部
１０４ 時機制御部
１０６ 飽和電荷量検出部
１０８ 仮定初期値算出部
１１０ 層厚算出部
１１２ 寿命判定部 DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming part 22 Image holding body 24 Charging member 62 Control unit 64 UI apparatus 70 CPU
72 Memory 82 Power supply unit 84 AC power supply 86 DC power supply 88 Current detection unit 90 Conductive support 92 Photosensitive layer 94 Charge generation layer 96 Charge transport layer 98 Protective layer 100 Life determination program 102 Cycle number detection unit 104 Time control unit 106 Saturation charge Quantity detection unit 108 Assumed initial value calculation unit 110 Layer thickness calculation unit 112 Life determination unit

Claims (7)

誘電率が所定値である第１の被覆層と、この第１の被覆層よりも誘電率が大きく、前記第１の被覆層をさらに被覆する第２の被覆層とを具備する像保持体と、この像保持体に接触又は近接して該像保持体を帯電させる帯電部材と、この帯電部材により帯電させられる前記像保持体の飽和電荷量を検出する飽和電荷量検出手段と、この飽和電荷量検出手段が検出する飽和電荷量に基づいて、前記第２の被覆層の層厚初期値を変えることなく、前記第２の被覆層の誘電率が前記第１の被覆層の誘電率と等しいと仮定した場合の飽和電荷量の仮定初期値を算出する仮定初期値算出手段と、この仮定初期値算出手段が算出する飽和電荷量の仮定初期値と前記飽和電荷量検出手段が検出する飽和電荷量との相対関係に基づいて、前記第１の被覆層の層厚を算出する層厚算出手段とを有する画像形成装置。   An image carrier comprising: a first coating layer having a predetermined dielectric constant; and a second coating layer having a dielectric constant larger than that of the first coating layer and further covering the first coating layer; A charging member for charging the image carrier in contact with or in proximity to the image carrier, a saturation charge amount detecting means for detecting a saturation charge amount of the image carrier charged by the charging member, and the saturation charge Based on the saturation charge amount detected by the quantity detection means, the dielectric constant of the second coating layer is equal to the dielectric constant of the first coating layer without changing the initial layer thickness of the second coating layer. An assumed initial value calculating means for calculating an assumed initial value of the saturated charge amount, and an assumed initial value of the saturated charge amount calculated by the assumed initial value calculating means and the saturated charge detected by the saturated charge amount detecting means. Based on the relative relationship with the amount, the thickness of the first coating layer Calculating an image forming apparatus having a layer thickness calculating means for. 前記仮定初期値算出手段は、前記第１の被覆層と前記第２の被覆層との層厚比及び誘電率比に基づいて、飽和電荷量の仮定初期値を算出する請求項１記載の画像形成装置。   2. The image according to claim 1, wherein the assumed initial value calculation means calculates an assumed initial value of a saturation charge amount based on a layer thickness ratio and a dielectric constant ratio between the first coating layer and the second coating layer. Forming equipment. 前記像保持体の動作量を検出する動作量検出手段と、前記飽和電荷量検出手段が飽和電荷量を検出する時機を制御する制御手段とをさらに有し、前記制御手段は、前記動作量検出手段が検出する動作量に基づいて、前記飽和電荷量検出手段が飽和電荷量の検出を再開するよう制御する請求項１又は２記載の画像形成装置。   The apparatus further includes an operation amount detection unit that detects an operation amount of the image carrier, and a control unit that controls when the saturation charge amount detection unit detects a saturation charge amount, and the control unit detects the operation amount detection 3. The image forming apparatus according to claim 1, wherein the saturation charge amount detection unit performs control so as to restart detection of the saturation charge amount based on an operation amount detected by the unit. 前記制御手段は、前記飽和電荷量検出手段が検出する飽和電荷量の検出結果及び検出精度に基づいて、前記飽和電荷量検出手段が飽和電荷量を検出する時機の間隔を制御する請求項３記載の画像形成装置。   The said control means controls the time interval when the said saturation charge amount detection means detects a saturation charge amount based on the detection result and detection accuracy of the saturation charge amount which the said saturation charge amount detection means detects. Image forming apparatus. 前記層厚算出手段が算出する前記第１の被覆層の層厚に基づいて、前記像保持体の寿命を判定する寿命判定手段をさらに有する請求項１乃至４いずれか記載の画像形成装置。   5. The image forming apparatus according to claim 1, further comprising a lifetime determining unit that determines a lifetime of the image carrier based on a layer thickness of the first covering layer calculated by the layer thickness calculating unit. 誘電率が所定値である第１の被覆層と、この第１の被覆層よりも誘電率が大きく、第１の被覆層をさらに被覆する第２の被覆層とを具備する被帯電体の飽和電荷量を検出し、第２の被覆層の層厚初期値を変えることなく、第２の被覆層の誘電率が第１の被覆層の誘電率と等しいと仮定して、検出した飽和電荷量に基づく飽和電荷量の仮定初期値を算出し、算出した飽和電荷量の仮定初期値とその後の被帯電体の飽和電荷量との相対関係に基づいて、第１の被覆層の層厚を算出することにより検出する層厚検出方法。   Saturation of an object to be charged comprising a first coating layer having a predetermined dielectric constant and a second coating layer having a dielectric constant larger than that of the first coating layer and further covering the first coating layer Detecting the amount of charge and assuming that the dielectric constant of the second coating layer is equal to the dielectric constant of the first coating layer without changing the initial layer thickness of the second coating layer, The assumed initial value of the saturated charge amount based on the calculated initial charge value is calculated, and the layer thickness of the first coating layer is calculated based on the relative relationship between the calculated assumed initial value of the saturated charge amount and the subsequent saturated charge amount of the charged object. Layer thickness detection method for detecting by doing. 誘電率が所定値である第１の被覆層と、この第１の被覆層よりも誘電率が大きく、第１の被覆層をさらに被覆する第２の被覆層とを具備する被帯電体の飽和電荷量を検出するステップと、第２の被覆層の層厚初期値を変えることなく、第２の被覆層の誘電率が第１の被覆層の誘電率と等しいと仮定して、検出した飽和電荷量に基づく飽和電荷量の仮定初期値を算出するステップと、算出した飽和電荷量の仮定初期値とその後の被帯電体の飽和電荷量との相対関係に基づいて、第１の被覆層の層厚を算出することにより検出するステップとをコンピュータに実行させる被帯電体の層厚検出プログラム。   Saturation of an object to be charged comprising a first coating layer having a predetermined dielectric constant and a second coating layer having a dielectric constant larger than that of the first coating layer and further covering the first coating layer Detecting the amount of charge and the detected saturation assuming that the dielectric constant of the second coating layer is equal to the dielectric constant of the first coating layer without changing the initial thickness of the second coating layer Based on the step of calculating the assumed initial value of the saturated charge amount based on the charge amount, and the relative relationship between the calculated assumed initial value of the saturated charge amount and the saturated charge amount of the object to be charged thereafter, the first covering layer A program for detecting a layer thickness of an object to be charged, which causes a computer to execute a step of detecting by calculating the layer thickness.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018097268A (en) * 2016-12-15 2018-06-21 コニカミノルタ株式会社 Image formation apparatus

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