Variable sheet guide position sensor

• US 5,573,236 A
• Filed: 08/05/1994
• Issued: 11/12/1996
• Est. Priority Date: 08/05/1994
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Damouth, David E., Acquaviva, Thomas, Petocchi, Ermanno C., Robinson, Norman D. Jr.
• Primary Examiner(s): SKAGGS JR, H GRANT
• Application Number:
  US08/286,352
• Time in Patent Office: 830 Days
• Field of Search: 250/214 PR, 250/559.19, 250/559.24, 250/559.26, 271/171, 271/265.01, 271/265.02, 271/145, 271/9.06, 355/311
• US Class Current: 271/265.02
• CPC Class Codes: B65H 1/00 Supports or magazines for piles from which articles are to be separated carriers used for associating, collating, or gathering articles B65H39/00
• CPC Class Codes: B65H 1/04 adapted to support articles substantially horizontally, e.g. for separation from top of pile
• 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 2220/02 indicating an entity which is controlled, adjusted or changed by a control process, i.e. output
• CPC Class Codes: B65H 2220/11 indicating that the input or output entities exclusively relate to machine elements
• CPC Class Codes: B65H 2511/10 Size; Dimensions
• CPC Class Codes: B65H 2511/20 Location in space
• CPC Class Codes: B65H 2553/40 using optical, e.g. photographic, elements
• CPC Class Codes: G03G 15/6502 Supplying of sheet copy material; Cassettes therefor
• CPC Class Codes: G03G 2215/00734 of sheet size

Abstract

An apparatus for determining the dimensions of a stack of sheets in the tray. An optical sensor is arranged so that movement of the sheet guides in a paper tray causes a variably graduated scale to be moved past the sensor. The sensor may either be a transmissive or reflective type analog sensor in which the strength of the signal generated by the sensor is converted into a position of the side guides and as the analog scale is continuously variable, there is no need for separate discrete sensors or switches and sheet sizes of any dimension can be accommodated. A recalibration process is used to prevent contamination of the gauge and the associated change in signal strength by this sensor from causing the size determinations to be inaccurate. Alternatively, a digital sensor in cooperation with a digital bar code or other digital scale can be utilized to determine the variable sheet size, which digital sensor and variable scale are insensitive to contamination by dirt or paper particles, etc. The sensor system herein is very robust and provides a simple device for determining the size of a stack of sheets in a paper tray.

Claims

1. An apparatus for detecting the size of a sheet, comprising:

an optical sensor;

a sheet position indicator;

a variable scale operatively associated with said optical sensor so that different sized sheets are positioned at different positions along said variable scale, wherein said sensor generates a signal uniquely indicative of the position of the sheet relative to said variable scale to provide an indication of the sheet size;

a second optical sensor;

a second sheet position indicator; and

a second variable scale operatively associated with said second optical sensor so that different sized sheets are positioned at different positions along said second variable scale, wherein said second sensor generates a signal uniquely indicative of the position of the sheet relative to said second variable scale to provide an indication of the sheet size; and

a first wiper member operatively associated with said first mentioned optical sensor to prevent contamination of said first mentioned variable scale.

2. An apparatus for detecting the size of a sheet comprising:

an optical sensor; and

a variable scale operatively associated with said optical sensor so that different sized sheets are positioned at different positions along said variable scale, wherein said sensor generates a signal uniquely indicative of the position of the sheet relative to said variable scale to provide an indication of the sheet size;

a second optical sensor; and

a second variable scale operatively associated with said second optical sensor so that different sized sheets are positioned at different positions along said second variable scale, wherein said second sensor generates a signal uniquely indicative of the position of the sheet relative to said second variable scale to provide an indication of the sheet size; and

a second wiper member operatively associated with said second optical sensor to prevent contamination of said second variable scale.

3. An electrophotographic printing machine having a device for detecting the size of a sheet, comprising:

an optical sensor;

a sheet position indicator;

a variable scale operatively associated with said optical sensor so that different sized sheets cause said sheet position indicator to be positioned at different positions along said variable scale, wherein said sensor generates a signal uniquely indicative of the position of the sheet relative to said variable scale to provide an indication of the sheet size;

a second optical sensor;

a second sheet position indicator;

a second variable scale operatively associated with said second optical sensor so that different sized sheets cause said second sheet position indicator to be positioned at different positions along said second variable scale, wherein said second sensor generates a signal uniquely indicative of the position of the sheet relative to said second variable scale to provide an indication of the sheet size; and

a first wiper member operatively associated with said first mentioned optical sensor to prevent contamination of said first mentioned variable scale.

4. An electrophotographic printing machine having a device for detecting the size of a sheet, comprising:

an optical sensor;

a variable scale operatively associated with said optical sensor so that different sized sheets are positioned at different positions along said variable scale, wherein said sensor generates a signal uniquely indicative of the position of the sheet relative to said variable scale to provide an indication of the sheet size;

a second optical sensor;

a second variable scale operatively associated with said second optical sensor so that different sized sheets are positioned at different positions along said second variable scale, wherein said second sensor generates a signal uniquely indicative of the position of the sheet relative to said second variable scale to provide an indication of the sheet size; and

a second wiper member operatively associated with said second optical sensor to prevent contamination of said second variable scale.