JP4499216B2

JP4499216B2 - Image forming apparatus

Info

Publication number: JP4499216B2
Application number: JP25913399A
Authority: JP
Inventors: 季文三村
Original assignee: Toshiba Corp; Toshiba TEC Corp
Current assignee: Toshiba Corp; Toshiba TEC Corp
Priority date: 1999-09-13
Filing date: 1999-09-13
Publication date: 2010-07-07
Anticipated expiration: 2019-09-13
Also published as: JP2001083843A

Description

【０００１】
【発明の属する技術分野】
本発明はプリンタや電子写真装置等画像形成装置において、通紙を伴わないプレラン動作中の異常発生により、感光体に現像剤やトナーが大量に付着するのを防止する画像形成装置に関する。
【０００２】
【従来の技術】
プリンタや電子写真装置等画像形成装置のトナー及びキャリアからなるいわゆる二成分現像剤にて現像を行う現像器にあっては、オートトナーセンサにより現像器内のトナー濃度を検知し、その検知結果に応じてトナー補給を行い、所望の現像濃度を保持している。このオートトナーセンサは、確実且つ安定にトナー濃度を検知するため、画像形成装置本体の設置時あるいは現像器の交換時等の最初のセットアップ時や現像剤を新品に交換した直後等に、現像剤を現像器内になじませ又、オートトナーセンサーの検知値の初期値を設定し直すために、従来は、通紙を伴わないで感光体を回転し現像器を作動する通称プレランを行っていた。
即ち、現像容器内で新品の現像剤を攪拌して現像剤中のトナーの帯電を立ち上げるとともに、感光体を数分間回転させて、その時のオートトナーセンサーの検知値を初期値として設定していた。
【０００３】
又画像形成装置にあっては、ある一定時間以上画像形成装置本体の主電源が遮断された後に電源を投入した場合（例えば、朝の電源投入時や、機体内の紙詰まり除去のためにフロントカバーを開閉した時等）にも、従来は、通紙を伴わないで感光体を回転し現像器を作動する上記プレランを行っていた。
【０００４】
【発明が解決しようとする課題】
しかしながら上記従来の画像形成装置においては、通紙を伴わないプレランを行う間に帯電部材の破損や、帯電トランス・現像バイアストランス等の不調あるいは、帯電部材の装着を忘れるなどの異常を発生していると、現像時、感光体に甚だしい量のトナーや現像剤の付着を生じてしまう。このため感光体に付着した大量のトナーにより感光体周囲や画像形成装置本体内を汚染したり、現像剤中のキャリアにより感光体やクリーニングブレード等感光体接触部材を損傷するという問題を有していた。しかも通紙をしていないため、被転写紙を目視しての異常の確認をすることが出来ず、異常の発見が遅れ、感光体へのより大量のトナーや現像剤付着により、被害を更に大きくするという問題を生じていた。
【０００５】
そこで本発明は上記課題を除去するもので、通紙を伴わないプレラン動作時に帯電装置や現像バイアス等に異常を生じた場合に、目視による事無く直ちにその異常を検知して感光体へのトナーあるいは現像剤のより大量の付着を防止し、画像形成装置本体内の汚損や、感光体及び感光体接触部材の損傷を生じる事無く、信頼性の高い画像形成装置を提供する事を目的とする。
【０００６】
【課題を解決するための手段】
本発明は上記課題を解決するために、ドラム状の像担持体と、この像担持体の回転に従い前記像担持体を一様に帯電する帯電手段と、この帯電手段により一様に帯電された前記像担持体上に静電潜像を形成する潜像形成手段と、この潜像形成手段位置を通過後の前記像担持体にトナーを付与する現像手段と、前記像担持体上のトナーを被転写体に転写する転写手段と、この転写手段位置通過後の前記像担持体上の残留トナーを除去するクリーニング手段と、前記現像手段から前記クリーニング手段に達する間に設けられ前記像担持体表面の反射率を検知する検知手段とを具備し、前記潜像形成手段による静電潜像形成動作及び前記転写手段による転写動作を伴わないで前記像担持体及び前記現像手段を作動しているプレラン時に、前記検知手段が所定値の範囲外であって、前記所定値の範囲より多量の前記トナーの付着を検出した時には、前記像担持体の回転を停止するものである。
【００１０】
上記手段により本発明は、通紙を伴わないプレラン動作時に、現像器からクリーニング手段に達する間に設けられる検知手段により像担持体表面の反射率を検知して、像担持体に甚だしいトナーや現像剤が付着していて、検知手段による検知結果が所定値の範囲外であれば、像担持体の回転を速やかに停止することにより、画像形成装置本体内の汚損や、感光体及び感光体接触部材の損傷を防止すると共に、像担持体への更なるトナーや現像剤の付着を防止出来、信頼性の高い画像形成装置を提供するものである。
【００１１】
【発明の実施の形態】
以下本発明を図１乃至図４に示す実施の形態を参照して説明する。図１は画像形成装置で有る複写機（図示せず）の画像形成部１０を示す概略構成図であり、像担持体であるドラム状の感光体１１周囲には帯電手段であり感光体１１を一様に−６５０Ｖに帯電する帯電チャージャ１２、画像情報を光情報に変換し感光体１１を走査露光して静電潜像を形成するする潜像形成手段で有る露光装置（図示せず）の露光部１３、感光体にトナーを付与する現像手段で有る現像器１４、感光体１１上のトナー像を被転写体で有るシート紙等に転写する転写手段で有り転写ベルト１６ａ、転写ローラ１６ｂを有する転写装置１６、剥離爪１７、感光体１１表面の反射率を検知する検知手段で有る反射率センサ１８、クリーニング装置２０、除電器２１がその回転方向に沿って順次配置されている。
【００１２】
又、２２は、図示しない給紙カセット装置或いは給紙トレイ等より供給されるシート紙を、感光体１１上に形成されるトナー像に同期して転写装置１６方向に搬送するレジストローラである。
【００１３】
現像器１４は、筐体１４ａ内にトナー及びキャリアからなる二成分現像剤を収容し、上下現像ローラ２３ａ、２３ｂには、図示しないバイアストランスにより−４５０Ｖの現像バイアスが印加されている。更に筐体１４ａ内には二成分現像剤を攪拌・搬送する第１及び第２のミキシングオーガ２４ａ、２４ｂが設けられ、第１のミキシングオーガ下方には、現像剤中のトナー濃度を検知するオートトナーセンサ２６が設けられている。
【００１４】
そして剥離爪１７、反射率センサ１８、クリーニング装置２０は、図２に示す様にクリーナーユニット２７に一体的に形成されている。発光部１８ａ及び受光部１８ｂにより構成される反射率センサ１８は、クリーナーユニット２７の剥離爪１７の間に設置されている。この反射率センサ１８は、通紙をせずに感光体１１上に形成される基準のパターンのトナー像の反射率を検知し、その検知結果が所望の範囲に入るように各プロセス条件を制御し、一定の画質を得ようとする画質維持制御に使用される基準パターン検知手段を兼用と共に、通紙をせずに感光体１１及び現像ローラ２３ａ、２３ｂを回転するプレラン時の感光体１１の反射率を検知し、帯電チャージャ１２や現像バイアスの異常の検知に使用される。
【００１５】
クリーニング装置２０は、ケース２０ａ上方にメインブレード２８を有し、ケース２０ａ下方にはリカバリーブレード３０を有している。又３１はケース２０ａ底面にて回収された残留トナーをケース２０ａの一側に搬送するトナー回収オーガ、３２は感光体１１上の残留トナーを除去するファーブラシである。
【００１６】
又図３は画像形成部１０のプレランを制御する制御系３５を示すブロック図であり、複写機本体を制御する制御装置３６には、出力インターフェース３７を介し、感光体１１及び現像器１４の各種ドライバ３８、高圧発生部４０、警告を表示する表示部４１が接続されている。又制御装置３６には、入力インターフェース４２を介し入力キー４３、反射率センサ１８、オートトナーセンサ２６、その他スイッチ・センサ類４４が接続されている。
【００１７】
次に図４に示すフローチャートを参照してプレラン時の作用について述べる。
ステップ１００のスタートにて複写機（図示せず）本体の電源を投入すると、ステップ１０１あるいはステップ１０２のいずれかに進む。ステップ１０１では、複写機本体設置時あるいは現像器の交換時等の最初のセットアップ時や現像剤を新品に交換した直後等にオートトナーセンサ２６を初期化するプレラン１を実施し、ステップ１０２では、ある一定時間以上画像形成装置本体の主電源が遮断された後に電源を投入した場合（例えば、朝の電源投入時や、複写機本体内の紙詰まり処置後等）のプレラン２を実施する。
【００１８】
そしてプレラン１、プレラン２のいずれであってもステップ１０３に進み感光体１１及び現像器１４を回転する。この時、帯電チャージャ１２、及び現像バイアスが正常であれば、感光体１１はその矢印ｘ方向の回転に従い、帯電チャージャ１２により一様に−６５０Ｖに帯電された状態で現像器１４に達する。現像器１４では現像バイアスが−４５０Ｖで有る事から、上下現像ローラ２３ａ、２３ｂから感光体１１側にトナー付着を生じる事無く、感光体１１は反射センサ１８に達する。
【００１９】
一方、ステップ１０３で、帯電チャージャ１２が異常であれば、感光体１１はその回転時、帯電チャージャ１２による帯電が成されず、その表面電位がほぼ０Ｖの状態で現像器１４に達する。このため、−４５０Ｖの現像バイアスが印可される上下現像ローラ２３ａ、２３ｂから感光体１１表面全面にトナー付着を生じこの状態で反射センサ１８に達する。
【００２０】
この後ステップ１０４に示す様に反射率センサ１８は、感光体１１表面の反射率を検出しステップ１０６に進む。即ち帯電チャージャ１２、及び現像バイアスが正常であり、感光体１１にトナーが付着していない場合、反射率センサ１８は感光体１１表面からの反射率が所定値（感光体１１表面にわずかにトナーとキャリアが付着している状態）の範囲内である旨を検知しており、ステップ１０７に進み、この後所定時間プレランを継続する。一方、帯電チャージャ１２及び／又は現像バイアスが異常であり、感光体１１表面全面にトナーが付着している場合、反射率センサ１８は感光体１１表面からの反射率が所定値の範囲外である旨を検知することから、ステップ１０８に進み、制御装置３６は、感光体１１及び現像器１４の回転を速やかに停止すると共に表示部４１に異常である旨の警告を表示する。
【００２１】
これにより、異常時、現像器１４から反射率センサ１８に達するまで感光体１１全面にトナー付着が見られるものの、更なる大量のトナー付着は防止される。
【００２２】
尚この様にしてなる画像形成部１０及び制御系３５を東芝テック社製デジタル複写機プリマージュ６５１に採用し、帯電チャージャ１２の図示しない給電部にスイッチを設け、帯電を遮断できるようにして、帯電チャージャ１２を正常状態と、異常状態とに切換えて、現像器１４のオートトナーセンサ２６の初期設定のためのプレラン操作を行った。
【００２３】
この結果、帯電チャージャ１２に給電を行いプレランを行った場合はオートトナーセンサ２６を良好に初期設定出来る。一方、帯電チャージャ１２の給電を遮断して、プレランを行った場合は感光体１１のトナー全面付着部は、反射率センサ１８に達した時点で感光体１１が速やかに停止される。これにより、感光体１１のトナーが全面に付着した部分がクリーニング装置２０のメインブレード２８に達する事が無く、その摺接による感光体１１やメインブレード２８の損傷を防止出来る。又、現像器１４から反射率センサ１８に達するまでの間にあっては、感光体１１の全面にトナー付着を生じるものの、その付着量は複写機本体内にトナー飛散を生じる程ではなく、感光体１１周辺装置の汚損も見られなかった。
【００２４】
この様に構成すれば、オートトナーセンサ２６を初期化するプレラン１あるいは、一定時間以上主電源が遮断された後の電源投入後のプレラン２において、帯電チャージャ１２や現像器１４に異常を生じ、感光体１１に大量のトナーあるいは現像剤が付着した場合には、反射率センサ１８が反射率が所定値の範囲外にあることを直ちに検知し、制御装置３６により感光体１１及び現像器１４の回転を速やかに停止し表示部４１に異常である旨の警告を表示出来る。従って感光体１１表面の現像剤の大量付着部がクリーニング装置２０のメインブレード２８に達する事が無く、摺接による感光体１１やメインブレード２８の損傷を防止出来る。又、異常発生にかかわらず感光体１１へのトナー等の大量付着を従来に比し著しく抑える事が出来、感光体１１の周辺装置の汚損や、トナー等の飛散による複写機本体内の汚損を防止出来、プレラン時の信頼性向上を得られる。
【００２５】
尚本発明は、上記実施の形態に限られるもので無く、その趣旨を変えない範囲での変更は可能であって、像担持体表面の反射率を検知する検知手段は画質維持制御のために基準パターンを検知する基準パターン検知手段との兼用で無くても良く、又その設置位置も、現像後、クリーニング手段に達するまでの間であれば任意である。又異常発生時の警告は、音声や、ランプ等限定されない、
【００２６】
【発明の効果】
以上説明したように本発明によれば、通紙を伴わないプレラン時に、像担持体上に大量のトナーあるいは現像剤が付着する異常を生じた場合には、像担持体表面を検知する検知手段にてその旨を直ちに検知し、像担持体及び現像手段を速やかに停止して、更なる現像剤等の付着を防止出来る。従って像担持体表面に大量に付着する現像剤等が周辺装置に付着して装置の汚損を生じたり、あるいはトナー飛散により複写機本体内の汚損を生じる事が無く、また、大量付着部をクリーニングする際に、キャリアにより像担持体やクリーニングブレードを損傷するおそれも無く、プレラン時の信頼性向上をえられる。そして現像手段にあっては、現像剤等による装置の汚損を生じる事無くオートトナーセンサの初期値設定を確実に行う事が出来る。
【図面の簡単な説明】
【図１】本発明の実施の形態の複写機の画像形成部を示す概略構成図である。
【図２】本発明の実施の形態のクリーナーユニットを示す概略正面図である。
【図３】本発明の実施の形態のプレラン操作の制御系を示すブロック図である。
【図４】本発明の実施の形態のプレラン時の作用を示すフローチャートである。
【符号の説明】
１０…画像形成部
１１…感光体
１２…帯電チャージャ
１３…露光部
１４…現像器
１６…転写装置
１８…反射率センサ
２０…クリーニング装置
２３ａ、２３ｂ…上下現像ローラ
２６…オートトナーセンサ
２７…クリーナーユニット
２８…メインブレード[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that prevents a large amount of developer and toner from adhering to a photoreceptor due to an occurrence of an abnormality during a pre-run operation without passing paper in an image forming apparatus such as a printer or an electrophotographic apparatus.
[0002]
[Prior art]
In a developing device that develops with a so-called two-component developer composed of toner and carrier of an image forming apparatus such as a printer or an electrophotographic apparatus, the toner density in the developing device is detected by an auto toner sensor, and the detection result is Accordingly, the toner is replenished to maintain a desired development density. This auto toner sensor detects the toner concentration reliably and stably, so that the developer can be used at the time of initial setup such as when the main body of the image forming apparatus is installed or when the developer is replaced or immediately after the developer is replaced with a new one. In the past, in order to reset the initial value of the detection value of the auto toner sensor, a so-called pre-run in which the photosensitive member is rotated and the developing device is operated without passing paper is performed. .
That is, a new developer is stirred in the developing container to raise the charge of the toner in the developer, and the photosensitive member is rotated for several minutes, and the detection value of the auto toner sensor at that time is set as an initial value. It was.
[0003]
Also, in the image forming apparatus, when the power is turned on after the main power of the image forming apparatus main body has been shut off for a certain period of time (for example, when the power is turned on in the morning or when the paper jam in the machine is removed) Conventionally, when the cover is opened and closed, the above pre-run for rotating the photosensitive member and operating the developing device without passing paper is performed.
[0004]
[Problems to be solved by the invention]
However, in the above conventional image forming apparatus, abnormalities such as breakage of the charging member, malfunction of the charging transformer / developing bias transformer, or forgetting to attach the charging member occur during pre-run without passing paper. If so, a significant amount of toner or developer adheres to the photoreceptor during development. For this reason, there are problems that a large amount of toner adhering to the photoconductor contaminates the periphery of the photoconductor and the inside of the image forming apparatus main body, and the photoconductor contact member such as the photoconductor and the cleaning blade is damaged by the carrier in the developer. It was. Moreover, because the paper is not passed, it is not possible to confirm the abnormality by visual inspection of the transfer paper, the discovery of the abnormality is delayed, and the damage is further increased by the larger amount of toner and developer adhering to the photoconductor. There was a problem of making it bigger.
[0005]
Accordingly, the present invention eliminates the above-described problem. When an abnormality occurs in the charging device or the developing bias during the pre-run operation without passing paper, the abnormality is immediately detected without visual observation, and the toner on the photosensitive member is detected. Alternatively, it is an object of the present invention to provide a highly reliable image forming apparatus that prevents a larger amount of developer from adhering to the image forming apparatus main body and causes no contamination of the image forming apparatus main body or damage to the photosensitive member and the photosensitive member contact member. .
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a drum-shaped image carrier, charging means for uniformly charging the image carrier according to the rotation of the image carrier, and charging uniformly by the charging means. A latent image forming unit for forming an electrostatic latent image on the image carrier, a developing unit for applying toner to the image carrier after passing through the position of the latent image forming unit, and a toner on the image carrier. A transfer means for transferring to the transfer body; a cleaning means for removing residual toner on the image carrier after passing through the position of the transfer means; and a surface of the image carrier provided between the developing means and the cleaning means And a pre- run that operates the image carrier and the developing unit without an electrostatic latent image forming operation by the latent image forming unit and a transfer operation by the transfer unit. in time, the detection hand There be outside the range of the predetermined value, upon detection of a large amount of the toner adhesion than the range of the predetermined value is for stopping the rotation of the image bearing member.
[0010]
By the above means, the present invention can detect the reflectance of the surface of the image carrier by the detection means provided while reaching the cleaning means from the developing unit during the pre-run operation without passing paper, and can generate a large amount of toner and developer on the image carrier. If the agent is attached and the detection result by the detection means is out of the predetermined value range, the rotation of the image carrier is quickly stopped, so that the contamination inside the image forming apparatus main body or the contact between the photoconductor and the photoconductor An object of the present invention is to provide a highly reliable image forming apparatus capable of preventing damage to members and preventing further toner and developer from adhering to an image carrier.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a schematic configuration diagram showing an image forming unit 10 of a copying machine (not shown) which is an image forming apparatus. A drum-shaped photoconductor 11 which is an image carrier is a charging means. A charging charger 12 that is uniformly charged to −650 V, and an exposure device (not shown) that is a latent image forming unit that converts image information into optical information and scans and exposes the photosensitive member 11 to form an electrostatic latent image. An exposure unit 13, a developing unit 14 that is a developing unit that applies toner to the photoconductor, a transfer unit that transfers a toner image on the photoconductor 11 to a sheet paper that is a transfer target, and a transfer belt 16a and a transfer roller 16b. A transfer device 16, a peeling claw 17, a reflectance sensor 18 serving as a detecting means for detecting the reflectance of the surface of the photoreceptor 11, a cleaning device 20, and a static eliminator 21 are sequentially arranged along the rotation direction.
[0012]
Reference numeral 22 denotes a registration roller that conveys sheet paper supplied from a sheet feeding cassette device or a sheet feeding tray (not shown) in the direction of the transfer device 16 in synchronization with the toner image formed on the photosensitive member 11.
[0013]
The developing device 14 contains a two-component developer composed of toner and carrier in a casing 14a, and a developing bias of −450 V is applied to the upper and lower developing rollers 23a and 23b by a bias transformer (not shown). Furthermore, first and second mixing augers 24a and 24b for stirring and transporting the two-component developer are provided in the housing 14a, and an auto-detection unit for detecting the toner concentration in the developer is provided below the first mixing auger. A toner sensor 26 is provided.
[0014]
The peeling claw 17, the reflectance sensor 18, and the cleaning device 20 are integrally formed with the cleaner unit 27 as shown in FIG. The reflectance sensor 18 including the light emitting unit 18 a and the light receiving unit 18 b is installed between the peeling claws 17 of the cleaner unit 27. The reflectance sensor 18 detects the reflectance of the toner image of the reference pattern formed on the photoconductor 11 without passing paper, and controls each process condition so that the detection result falls within a desired range. In addition, the reference pattern detecting means used for the image quality maintenance control for obtaining a constant image quality is also used, and the photoconductor 11 at the time of pre-run that rotates the photoconductor 11 and the developing rollers 23a and 23b without passing paper is used. The reflectance is detected and used to detect abnormalities in the charging charger 12 and the developing bias.
[0015]
The cleaning device 20 has a main blade 28 above the case 20a and a recovery blade 30 below the case 20a. Reference numeral 31 denotes a toner collection auger that conveys residual toner collected on the bottom surface of the case 20a to one side of the case 20a, and 32 denotes a fur brush that removes residual toner on the photoconductor 11.
[0016]
FIG. 3 is a block diagram showing a control system 35 for controlling the pre-run of the image forming unit 10. The control device 36 for controlling the copying machine main body is connected to various types of the photoreceptor 11 and the developing device 14 via an output interface 37. A driver 38, a high pressure generator 40, and a display 41 for displaying a warning are connected. Further, an input key 43, a reflectance sensor 18, an auto toner sensor 26, and other switches / sensors 44 are connected to the control device 36 through an input interface 42.
[0017]
Next, the operation during pre-run will be described with reference to the flowchart shown in FIG.
When the power of the copying machine (not shown) is turned on at the start of step 100, the process proceeds to either step 101 or step 102. In step 101, pre-run 1 for initializing the auto toner sensor 26 is performed at the time of initial setup such as when the copying machine main body is installed or when the developing device is replaced or immediately after the developer is replaced with a new one. A pre-run 2 is performed when the power is turned on after the main power of the image forming apparatus main body has been shut off for a certain period of time (for example, when the power is turned on in the morning or after a paper jam has been cleared in the copying machine main body).
[0018]
Then, in either pre-run 1 or pre-run 2, the process proceeds to step 103 and the photosensitive member 11 and the developing device 14 are rotated. At this time, if the charging charger 12 and the developing bias are normal, the photoconductor 11 reaches the developing unit 14 in a state of being uniformly charged to −650 V by the charging charger 12 according to the rotation in the arrow x direction. Since the developing unit 14 has a developing bias of −450 V, the photosensitive member 11 reaches the reflection sensor 18 without causing toner adhesion from the upper and lower developing rollers 23 a and 23 b to the photosensitive member 11 side.
[0019]
On the other hand, if the charging charger 12 is abnormal in step 103, the photosensitive member 11 is not charged by the charging charger 12 during its rotation, and reaches the developing device 14 with its surface potential being approximately 0V. For this reason, toner adheres to the entire surface of the photoreceptor 11 from the upper and lower developing rollers 23a and 23b to which a developing bias of −450 V is applied, and reaches the reflection sensor 18 in this state.
[0020]
Thereafter, as shown in step 104, the reflectance sensor 18 detects the reflectance of the surface of the photoconductor 11, and proceeds to step 106. That is, when the charging charger 12 and the developing bias are normal and the toner is not attached to the photosensitive member 11, the reflectance sensor 18 has a predetermined reflectance (a slight amount of toner on the surface of the photosensitive member 11). And the carrier is in a state of being attached), the process proceeds to step 107, and then pre-run is continued for a predetermined time. On the other hand, when the charging charger 12 and / or the developing bias is abnormal and the toner adheres to the entire surface of the photosensitive member 11, the reflectance from the surface of the photosensitive member 11 is out of the predetermined value range. The control device 36 promptly stops the rotation of the photoconductor 11 and the developing device 14 and displays a warning indicating that there is an abnormality on the display unit 41.
[0021]
As a result, when an abnormality occurs, toner adhesion is observed on the entire surface of the photoconductor 11 until the reflectance sensor 18 is reached from the developing device 14, but further large amount of toner adhesion is prevented.
[0022]
The image forming unit 10 and the control system 35 formed in this way are adopted in the TOSHIBA TEC digital copier pre-image 651, and a switch is provided in a power supply unit (not shown) of the charging charger 12 so as to cut off the charging. The pre-run operation for the initial setting of the auto toner sensor 26 of the developing device 14 was performed by switching the charger 12 between a normal state and an abnormal state.
[0023]
As a result, when power is supplied to the charging charger 12 and pre-run is performed, the auto toner sensor 26 can be favorably initialized. On the other hand, when the precharge is performed with the power supply of the charging charger 12 shut off, the photosensitive member 11 is immediately stopped when the toner entire surface adhesion portion of the photosensitive member 11 reaches the reflectance sensor 18. As a result, the portion of the photoconductor 11 where the toner adheres to the entire surface does not reach the main blade 28 of the cleaning device 20, and damage to the photoconductor 11 and the main blade 28 due to the sliding contact can be prevented. In addition, although toner adheres to the entire surface of the photoconductor 11 from the developing device 14 until the reflectance sensor 18 is reached, the adhering amount is not so large as to cause toner scattering in the copying machine main body. There was no contamination of the peripheral equipment.
[0024]
With this configuration, in the pre-run 1 for initializing the auto toner sensor 26 or in the pre-run 2 after the power is turned on after the main power is shut off for a certain time, an abnormality occurs in the charging charger 12 and the developing device 14, When a large amount of toner or developer adheres to the photoreceptor 11, the reflectance sensor 18 immediately detects that the reflectance is out of the predetermined value range, and the controller 36 controls the photoreceptor 11 and the developer 14. The rotation can be quickly stopped and a warning that there is an abnormality can be displayed on the display unit 41. Therefore, a large amount of developer adhering portion on the surface of the photoconductor 11 does not reach the main blade 28 of the cleaning device 20, and damage to the photoconductor 11 and the main blade 28 due to sliding contact can be prevented. In addition, a large amount of toner or the like adheres to the photoconductor 11 regardless of the occurrence of an abnormality, which can be remarkably suppressed as compared with the prior art. Can be prevented, and improved reliability during pre-run.
[0025]
The present invention is not limited to the above-described embodiment, and can be changed without departing from the spirit of the present invention. The detection means for detecting the reflectance of the surface of the image carrier is used for image quality maintenance control. It does not have to be combined with the reference pattern detection means for detecting the reference pattern, and the installation position is arbitrary as long as it is after development until the cleaning means is reached. Also, the warning when an abnormality occurs is not limited to voice, lamp, etc.
[0026]
【The invention's effect】
As described above, according to the present invention, in the pre-run without passing paper, when an abnormality occurs in which a large amount of toner or developer adheres to the image carrier, the detection unit detects the surface of the image carrier. This can be immediately detected, and the image carrier and the developing means can be quickly stopped to prevent further adhesion of developer or the like. Therefore, a large amount of developer or the like adhering to the surface of the image carrier adheres to the peripheral device and causes no contamination of the device, or contamination of the copying machine main body due to toner scattering, and the large amount of adhesion portion is cleaned. In this case, there is no risk of damaging the image carrier and the cleaning blade by the carrier, and the reliability during pre-run can be improved. In the developing means, it is possible to reliably set the initial value of the auto toner sensor without causing the device to be soiled by the developer or the like.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an image forming unit of a copier according to an embodiment of the present invention.
FIG. 2 is a schematic front view showing a cleaner unit according to the embodiment of the present invention.
FIG. 3 is a block diagram showing a control system for a pre-run operation according to the embodiment of the present invention.
FIG. 4 is a flowchart showing an operation during pre-run according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Image forming part 11 ... Photoconductor 12 ... Charger 13 ... Exposure part 14 ... Developing device 16 ... Transfer device 18 ... Reflectance sensor 20 ... Cleaning device 23a, 23b ... Upper and lower developing roller 26 ... Auto toner sensor 27 ... Cleaner unit 28 ... Main blade

Claims

A drum-shaped image carrier;
Charging means for uniformly charging the image carrier according to the rotation of the image carrier;
Latent image forming means for forming an electrostatic latent image on the image carrier uniformly charged by the charging means;
Developing means for applying toner to the image carrier after passing through the latent image forming means position;
Transfer means for transferring the toner on the image carrier to the transfer target;
Cleaning means for removing residual toner on the image carrier after passing through the transfer means position;
A detecting means provided between the developing means and the cleaning means for detecting the reflectance of the image carrier surface;
During the pre-run when the image carrier and the developing unit are operated without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit, the detection unit is out of a predetermined value range . The image forming apparatus is characterized in that the rotation of the image carrier is stopped when it is detected that a larger amount of the toner is attached than the predetermined value range .

A drum-shaped image carrier;
Charging means for uniformly charging the image carrier according to the rotation of the image carrier;
Latent image forming means for forming an electrostatic latent image on the image carrier uniformly charged by the charging means;
Developing means for applying toner to the image carrier after passing through the latent image forming means position;
Transfer means for transferring the toner on the image carrier to the transfer target;
Cleaning means for removing residual toner on the image carrier after passing through the transfer means position;
A detecting means provided between the developing means and the cleaning means for detecting the reflectance of the image carrier surface;
During the pre-run when the image carrier and the developing unit are operated without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit, the detection unit is out of a predetermined value range . An image forming apparatus characterized in that when an adhesion of a larger amount of the toner than the predetermined value is detected, rotation of the image carrier is stopped and a warning is generated.

A drum-shaped image carrier;
Charging means for uniformly charging the image carrier according to the rotation of the image carrier;
Latent image forming means for forming an electrostatic latent image on the image carrier uniformly charged by the charging means;
Developing means for applying toner to the image carrier after passing through the latent image forming means position;
Transfer means for transferring the toner on the image carrier to the transfer target;
Cleaning means for removing residual toner on the image carrier after passing through the transfer means position;
A reference pattern detecting unit provided between the developing unit and the cleaning unit, and detecting a reflectance of a reference pattern formed on the image carrier without a transfer operation by the transfer unit;
During the pre-run when the image carrier and the developing unit are operated without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit, the reference pattern detection unit is out of a predetermined value range. The image forming apparatus is characterized in that the rotation of the image carrier is stopped when it is detected that a larger amount of the toner is attached than the predetermined value range .

A drum-shaped image carrier;
Charging means for uniformly charging the image carrier according to the rotation of the image carrier;
Latent image forming means for forming an electrostatic latent image on the image carrier uniformly charged by the charging means;
Developing means for applying toner to the image carrier after passing through the latent image forming means position;
Transfer means for transferring the toner on the image carrier to the transfer target;
Cleaning means for removing residual toner on the image carrier after passing through the transfer means position;
A reference pattern detecting unit provided between the developing unit and the cleaning unit, and detecting a reflectance of a reference pattern formed on the image carrier without a transfer operation by the transfer unit;
During the pre-run when the image carrier and the developing unit are operated without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit, the reference pattern detection unit is out of a predetermined value range. The image forming apparatus is characterized in that when an adhesion of a larger amount of the toner than the range of the predetermined value is detected, the rotation of the image carrier is stopped and a warning is generated .

The initial setting of the auto toner sensor of the developing means is performed during the pre-run when the image carrier and the developing means are operated without the electrostatic latent image forming operation by the latent image forming means and the transfer operation by the transfer means. 5. The image forming apparatus according to claim 1, wherein the image forming apparatus is in a pre-run time .