Print media detector and method for use in a printing device

• US 6,365,889 B1
• Filed: 02/24/1999
• Issued: 04/02/2002
• Est. Priority Date: 02/24/1999
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Elgee, Steven B.
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/256,974
• Time in Patent Office: 1,133 Days
• Field of Search: 250/221, 347/101, 347/102, 347/14
• US Class Current: 250/221
• CPC Class Codes: B41J 11/009 Detecting type of paper, e.g. by automatic reading of a code that is printed on a paper package or on a paper roll or by sensing the grade of translucency of the paper
• CPC Class Codes: B65H 2220/01 indicating an entity as a function of which control, adjustment or change is performed, i.e. input
• CPC Class Codes: B65H 2220/03 indicating an entity which is measured, estimated, evaluated, calculated or determined but which does not constitute an entity which is adjusted or changed by the control process per se
• CPC Class Codes: B65H 2511/40 Identification
• CPC Class Codes: B65H 2511/416 of material
• CPC Class Codes: B65H 2511/51 Presence
• CPC Class Codes: B65H 2515/60 Optical characteristics, e.g. colour, light
• CPC Class Codes: B65H 2553/412 in barrier arrangements, i.e. emitter facing a receptor element
• CPC Class Codes: B65H 2557/64 for detecting type or properties of handled material
• CPC Class Codes: B65H 2701/1712 Transparent
• CPC Class Codes: B65H 7/14 by photoelectric feelers or detectors
• CPC Class Codes: G03G 15/65 Apparatus which relate to the handling of copy material handling sheets or webs in general B65H; for photographic purposes in general G03B
• CPC Class Codes: G03G 15/6591 characterised by the recording material, e.g. plastic material, OHP, ceramics, tiles, textiles details transferring the toner pattern onto particular materials G03G15/1625
• CPC Class Codes: G03G 15/6594 characterised by the format or the thickness, e.g. endless forms
• CPC Class Codes: G03G 2215/00497 Overhead Transparency, i.e. OHP
• CPC Class Codes: G03G 2215/00552 Purge of recording medium at jam
• CPC Class Codes: G03G 2215/00751 of sheet type, e.g. OHP

Abstract

A print media detection system for use in a printing device is disclosed. An embodiment of the print media detection system includes a source configured to transmit a light signal and a sensor configured to detect the light signal and generate an electrical signal in response to the light signal, the electrical signal having a magnitude that increases up to a substantially constant value as an intensity of the light signal from the source increases. The sensor is also configured to generate the electrical signal with a first magnitude for a transparent print media through which the light signal from the source travels to the sensor. The sensor is further configured to generate the electrical signal with a second magnitude less than the first magnitude for nontransparent print media positioned in a path of the light signal from the source to the sensor. A printing device including the print media detection system is also disclosed. A method of detecting transparent and nontransparent print media for use in a printing device is additionally disclosed. Further characteristics and features of the print media detection system, printing device, and method are described herein, as are examples of various alternative embodiments.

Claims

1. A print media detection system for use in a printing device, the print media detection system comprising:

means for transmitting a light signal;

means for sensing the light signal and producing an electrical signal having a first magnitude for a transparent print media through which the light signal travels and a second magnitude less than the first magnitude for nontransparent print media positioned in a path of the light signal from the source to the sensor; and

focus means incorporated into the means for transmitting light for ensuring that lightweight media is sensed as nontransparent print media, wherein lightweight media is media that, in the absence of the focus means, would not substantially attenuate the light.

2. The print media detection system of claim 1, further comprising means coupled to the means for sensing for controlling an operating parameter of the printing device based at least in part on the electrical signal received from the means for sensing.

3. The print media detection system of claim 1, wherein the focus means includes a focused light emitting diode.

4. The print media detection system of claim 1, wherein the means for sensing includes a phototransistor.

5. The print media detection system of claim 1, in a printing device.

6. A method of detecting transparent and nontransparent print media for use in a printing device, the method comprising:

transmitting a light signal toward a sheet of print media;

controlling the light signal so that it is substantially attenuated by lightweight media that has a transparence characteristic that is between nontransparent print media and transparent print media;

measuring an intensity of light at a sensor positioned along a path of the light signal, the sheet of print media being positioned between the light signal and the sensor;

generating one of an electrical signal having a first magnitude for a measured intensity of light substantially equal to an intensity of the light signal and an electrical signal having a second magnitude less than the first magnitude for a measured intensity of light less than the intensity of the light signal.

7. The method of claim 6, further comprising controlling an operating parameter of the printing device based at least in part on the electrical signal.