Variable speed printing

• US 20070248374A1
• Filed: 04/19/2007
• Published: 10/25/2007
• Est. Priority Date: 04/21/2006
• Status: Active Grant

• Current Assignee: Océ-Technologies B.V. (Canon Inc.)
• Original Assignee: Océ-Technologies B.V. (Canon Inc.)
• Inventors: Fabel, Ronald, La Vos, Peter G., Waarsing, Berend J.W., Heeman, Frederik G., Burger, Johan H.
• Granted Patent: US 8,231,287 B2
• Time in Patent Office: Days
• US Class Current: 399/82
• CPC Class Codes: G03G 15/6564 with correct timing of sheet feeding
• CPC Class Codes: G03G 2215/00945 Copy material feeding speed varied over the feed path
• CPC Class Codes: G03G 2215/00949 Copy material feeding speed switched according to current mode of the apparatus, e.g. colour mode

Abstract

An image reproduction device for document processing has a nominal processing speed at which it can process sheets continuously at a nominal document quality. However, the image reproduction device is arranged to process sheets at a continuously variable processing speed including the nominal processing speed. The actual processing speed is selected in dependence on operational conditions. In particular, the device is arranged to gradually adjust the processing speed from one processing speed to another processing speed. A control structure is given to select the variable processing speed in dependence on operational conditions, and to operate the image reproduction device at the selected processing speed. In a particular application of the variable speed, a print job may be started at an increased processing speed and then gradually fall back to the nominal speed, giving a fast start and a shorter processing time for short print jobs.

Claims

1. An image reproduction device for document processing, said image processing device comprising:

an input unit that provides sheets;

a document conveying system that conveys the sheets from the input unit to an output unit to receive processed documents;

a sheet processing system that applies an image pattern to a sheet while the sheet is being conveyed from the input unit to the output unit at a processing speed; and

a control unit, said control unit being arranged to;

process the sheets at a nominal processing speed, at a nominal sheet distance and a nominal document quality, the image reproduction device being arranged to operate at the nominal processing speed continuously; and

process the sheets at a second processing speed, the second processing speed being different from the nominal processing speed while the sheets are processed at the nominal sheet distance and the nominal document quality,

wherein the image reproduction device is arranged to operate at a continuously variable processing speed in a range of processing speeds in which the documents are processed at the nominal sheet distance and the nominal document quality, which range includes the second processing speed, and the control unit is further arranged to select a processing speed in the range of processing speeds in dependence on operational conditions, and operate the image reproduction device at the selected processing speed.

2. The device as claimed in claim 1, wherein the control unit is arranged to gradually adjust the processing speed from one processing speed to another processing speed.

3. The device as claimed in claim 1, wherein the control unit is arranged to select a processing speed that is higher than the nominal processing speed, in dependence on first operational conditions.

4. The device as claimed in claim 3, wherein the control unit is arranged to maintain a selected processing speed higher than the nominal processing speed for a time period selected in dependence on the first operational conditions.

5. The device as claimed in claim 3, wherein the first operational conditions comprise a job setting, timing, page count or a sensor signal.

6. The device as claimed in claim 3, wherein the control unit is arranged to determine a period of increased processing speed to perform jobs at a predetermined productivity independent of the actual job size.

7. The device as claimed in claim 3, wherein the first operational conditions comprise:

detecting a high priority job;

or

detecting an interrupt job that has to be processed while an earlier job is being processed.

8. The device as claimed in claim 3, wherein said first operational conditions comprise a processing mode and selecting the higher processing speed in dependence on the processing mode.

9. The device as claimed in claim 8, wherein said processing mode is duplex printing and wherein the control unit operates the device at an increased processing speed and adjusts processing timing to be acceptable for the output unit.

10. The device as claimed in claim 1, wherein the control unit is arranged to select a processing speed that is lower than the nominal processing speed, in dependence on second operational conditions.

11. The device as claimed in claim 10, wherein said second operational conditions comprise an operational parameter, said operational parameter being fuser temperature or available energy supply.

12. The device as claimed in claim 1, further comprising an output unit that delivers processed documents, wherein the control unit is arranged to detect a finishing parameter of the output unit, and to adjust processing speed and timing in dependence on the finishing parameter.

13. The device as claimed in claim 12, wherein the control unit is arranged to initially select an increased processing speed and subsequently reduce the speed to a required sheet receiving speed of the output unit.

14. The device as claimed in claim 1, further comprising a scanner unit, wherein the control unit is arranged to execute a scan job at a scan speed in dependence on the selected processing speed.

15. The device as claimed in claim 1, further comprising a plurality of units to control individual elements of the sheet processing system and the document conveying system, wherein the control unit is arranged to determine a sheet position of at least one sheet being conveyed, and communicate commands with the units to control the individual elements at respective operational speeds in dependence on the sheet position.

16. A method of controlling an image reproduction device for document processing, the device comprising an input unit that provides sheets, a document conveying system that conveys the sheets from the input unit to an output unit for receiving processed documents, a sheet processing system that applies an image pattern to a sheet while the sheet is being conveyed from the input unit to the output unit at a processing speed, said method comprising the steps of:

processing the sheets at a nominal processing speed, at a nominal sheet distance and a nominal document quality, said nominal processing speed being a processing speed at which the image reproduction device can operate continuously;

processing the sheets at a second processing speed, the second processing speed being different from the nominal processing speed while the sheets are processed at the nominal sheet distance and the nominal document quality;

operating the image reproduction device at a continuously variable processing speed in a range of processing speeds in which the documents are processed at the nominal sheet distance and the nominal document quality, which range includes the second processing speed;

selecting a processing speed in the range of processing speeds in dependence on operational conditions; and

operating the image reproduction device at the selected processing speed.

17. The method as claimed in claim 16, further comprising the step of gradually adjusting the processing speed from one processing speed to another processing speed.

18. The method as claimed in claim 16, further comprising the step of gradually adjusting the processing speed to a processing speed higher than the nominal speed for a limited time period in dependence on first operational conditions.

19. The method as claimed in claim 16, further comprising the step of gradually adjusting the processing speed to a processing speed lower than the nominal speed in dependence on second operational conditions.

20. The method as claimed in claim 16, further comprising the steps of:

controlling individual elements of the sheet processing system and the document conveying system;

determining a sheet position of at least one sheet being conveyed; and

communicating commands for operating the individual elements at respective operational speeds in dependence on the sheet position.