Contamination sensor

• US 4,099,861 A
• Filed: 11/10/1976
• Issued: 07/11/1978
• Est. Priority Date: 11/10/1976
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Abel, Frank Bernard
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US05/740,527
• Time in Patent Office: 608 Days
• Field of Search: 15/319, 15/339, 323/21, 340/237 P, 340/239 F, 355/15, 250/215
• US Class Current: 399/34
• CPC Class Codes: A47L 9/2815 using optical detectors
• CPC Class Codes: A47L 9/2857 User input or output elements for control, e.g. buttons, switches or displays
• CPC Class Codes: A47L 9/2889 Safety or protection devices or systems, e.g. for prevention of motor over-heating or for protection of the user
• CPC Class Codes: G03G 21/0005 for removing solid developer or debris from the electrographic recording medium

Abstract

A contamination sensor for monitoring exhaust path of the cleaning apparatus of an electrophotographic copier/duplicator to determine a malfunction condition in the cleaning apparatus. The sensor includes a light emitting diode (LED) placed in the exhaust path of the cleaning apparatus downstream of the final filter thereof and an optical sensor positioned to view the LED. The optical sensor produces a signal dependent upon the concentration of particulate toner in the exhaust path. The optical sensor is connected to the inverting input of a integrated circuit comparator wherein the signal from the optical sensor is compared to a reference signal. When the reference signal is exceeded, a circuit breaker is opened to give an appropriate alarm and/or shut down the copier/duplicator.

Claims

1. In a cleaning apparatus for removing particulate toner material from the photoconductive member of an electrophotographic copier, said cleaning apparatus including means for generating an air stream to entrain the removed particulate toner material and means for separating the entrained particulate toner material from the air stream, sensor means for determining an abnormal condition in said cleaning apparatus, said sensor means comprising:

means for producing a first signal indicative of the concentration of particulate toner material entrained in said air stream, said first signal producing means being located in the air stream downstream of said separating means and said generating means;

means for producing a reference signal representative of an abnormal concentration of particulate toner material; and

means for comparing said first signal with said reference signal, said comparing means including means for producing a second signal when said first signal exceeds said reference signal and means responsive to said second signal for shutting down the electrophotographic copier.

2. The invention of claim 1 wherein said first signal producing means comprises:

a support mounted in said air stream downstream of said separating means and said generating means;

emitting means positioned in said support for emitting a radiant energy signal through said air stream; and

receiving means positioned in said support opposite said emitting means for receiving said radiant energy signal passing through said air stream, the level of said radiant energy signal as received by said receiving means being reduced in direct proportion to the amount of particulate toner material in said air stream, said receiving means being responsive to the level of said radiant energy signal as received for producing said first signal which is inversely proportional to the received level of said radiant energy signal.

3. The invention of claim 2 wherein said emitting means is a light emitting diode and said receiving means is a photocell.

4. The invention of claim 2 wherein said second signal producing means comprises:

an operational amplifier having a threshold level representative of abnormal concentration of particulate toner material in said air stream, a clamping circuit normally maintaining the output of said operational amplifier at zero, and circuit means coupled to said receiving means for turning said operational amplifier on to produce said second signal when said first signal from said receiving means exceeds the threshold level.

5. The invention of claim 4 wherein said means for shutting down the electrophotographic copier comprises:

a circuit breaker interconnected with the electrophotographic copier control, said circuit breaker being operatively coupled to said operational amplifier so as to be opened upon the production of said second signal by said operational amplifier.

6. A method of determining a malfunction condition in a vacuum cleaning apparatus for an electrophotographic copier, and shutting down the electrophotographic copier upon the occurrence of such malfunction condition, said method including the steps of:

determining the concentration of particulate toner material in the air stream of the vacuum cleaning apparatus immediately upstream of point at which said air stream passes into the environment surrounding said electrophotographic copier;

comparing the concentration of particulate toner material in the air stream with a predetermined maximum permissible concentration of particulate toner material in the air stream; and

shutting down the electrophotographic copier when the determined concentration of particulate toner material exceeds the predetermined maximum permissible concentration of particulate material.

7. The invention of claim 6 further including the step of providing an alarm when said particulate toner material in the air stream exceeds the predetermined maximum permissible concentration of particulate toner material.