JPH0375440U

JPH0375440U -

Info

Publication number: JPH0375440U
Application number: JP13607089U
Authority: JP
Priority date: 1989-11-27
Filing date: 1989-11-27
Publication date: 1991-07-29

Description

[Brief explanation of drawings]

第１図は本考案を利用する複写装置の一例の説
明図、第２図は基準パターンと露光光源を示す説
明図、第３図はトナー濃度検知センサの構造を示
す平面図、第４図は制御装置のブロツク図、第５
図は制御装置の一部の回路図でＡはメイン制御部
、Ｂはイレーサに関する回路図、第６図は操作部
の平面説明図、第７図はイレーサ制御フローチヤ
ートである。１……感光体、２……帯電チヤージヤ、３……
ミラー、４……イレーサ、５，６……現像器、７
……転写前除電ランプ、８……転写チヤージヤ、
１２……クリーニング装置、１３……除電ランプ
、１４……トナー濃度検知センサ、２１……モー
タ。 FIG. 1 is an explanatory diagram of an example of a copying apparatus using the present invention, FIG. 2 is an explanatory diagram showing a reference pattern and an exposure light source, FIG. 3 is a plan view showing the structure of a toner concentration detection sensor, and FIG. Block diagram of the control device, No. 5
The figures are circuit diagrams of a part of the control device, in which A is a main control section, B is a circuit diagram relating to the eraser, FIG. 6 is a plan view of the operating section, and FIG. 7 is an eraser control flowchart. 1... Photoreceptor, 2... Charger, 3...
Mirror, 4...Eraser, 5, 6...Developer, 7
...Pre-transfer static elimination lamp, 8...Transfer charger,
12... Cleaning device, 13... Static elimination lamp, 14... Toner concentration detection sensor, 21... Motor.

Claims

[Scope of Utility Model Registration Claim] A toner image formed by charging, exposing, and developing a photoreceptor is transferred to a transfer material, at which time a reference pattern is exposed on the photoreceptor, and the charge is erased from non-image areas with an eraser. The reference pattern toner image and the photoreceptor background density are detected by a light reflection type toner density detection sensor, and the toner density of the developing device is controlled based on the value of the ratio between the reference pattern image density and the photoreceptor background density. In a copying apparatus, when a predetermined number of copies is reached, the toner density sensor is scanned in the axial direction of the photoreceptor to detect the density of the background portion of the photoreceptor, and when the detection output is less than a preset value, The voltage applied to the eraser is switched to a voltage higher than the normal voltage, and if the detection output of the toner density sensor is less than the set value when the next predetermined number of copies is reached, a warning is displayed on the operation unit and copying is prohibited. A copying apparatus characterized in that the voltage applied to the eraser is returned to the normally used voltage when the voltage exceeds a set value.