Image forming apparatus for forming image on sheet

Patent metadata

Field	Value
Publication number	US-9802778-B2
Application number	US-201615184026-A
Country	US
Kind code	B2
Filing date	Jun 16, 2016
Priority date	Jun 26, 2015
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

An image forming apparatus may comprise the following elements. A stacking unit in which a sheet is stacked. A conveyance unit conveys the sheet. A time-counting unit counts a conveyance time from when the conveyance unit starts to convey the sheet until the sheet arrives at a predetermined position on a conveyance path. A determination unit determines that over stacking has occurred, if the conveyance time of the sheet exceeds a first over stacking threshold value.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a stacking unit in which a sheet is stacked;
a conveyance unit configured to convey the sheet stacked in the stacking unit;
a time-counting unit configured to count a conveyance time from when the conveyance unit starts to convey the sheet until the sheet arrives at a predetermined position on a conveyance path; and
a determination unit configured to determine that over stacking in the stacking unit has occurred, upon the conveyance time of the sheet exceeding a first over stacking threshold value.

2. The image forming apparatus according to claim 1 , further comprising:
a detection unit configured to detect that a conveyance delay or a jam has occurred on the sheet based on whether or not the conveyance time of the sheet exceeds a conveyance delay threshold value for stopping image formation and discharging the sheet or a jam threshold value for stopping image formation and conveyance of the sheet,
wherein the first over stacking threshold value is smaller than the conveyance delay threshold value and the jam threshold value.

3. The image forming apparatus according to claim 2 , further comprising
a substituting unit configured to cause the determination unit to determine that over stacking in the stacking unit has occurred by substituting a value larger than the first over stacking threshold value for the conveyance time in a case that the sheet does not arrive at the predetermined position within a predetermined time.

4. The image forming apparatus according to claim 1 , further comprising
a detection unit configured to detect the sheet conveyed by the conveyance unit at the predetermined position,

wherein the time-counting unit is further configured to count the conveyance time from when the conveyance unit starts to convey the sheet until the detection unit detects the sheet.

5. The image forming apparatus according to claim 1 ,
wherein the determination unit executes the over stacking determination from when the conveyance unit starts a conveyance job for the sheet until a predetermined number of sheets are conveyed.

6. The image forming apparatus according to claim 1 , further comprising:
a measuring unit configured to measure an environmental condition of an environment in which the image forming apparatus is set,
wherein the determination unit executes the over stacking determination upon the environmental condition measured by the measuring unit being a predetermined environmental condition.

7. The image forming apparatus according to claim 6 ,
wherein the predetermined environmental condition is that an absolute amount of vapor is smaller than or equal to a predetermined amount of vapor, an environmental temperature is lower than or equal to a predetermined temperature, and environmental humidity is lower than or equal to a predetermined humidity.

8. The image forming apparatus according to claim 1 ,
wherein the stacking unit has a regulating member that regulates a height of a sheet bundle stacked in the stacking unit.

9. The image forming apparatus according to claim 1 , further comprising:
an identifying unit configured to identify a type of the sheet,
wherein the determination unit executes the over stacking determination upon the type of the sheet being identified as an envelope type sheet.

10. The image forming apparatus according to claim 9 ,
wherein the identifying unit is configured to identify the type of the sheet as the envelope type sheet upon an envelope mode being designated from among a plurality of control modes provided in the image forming apparatus.

11. The image forming apparatus according to claim 9 , further comprising:
a size designation unit configured to designate a size of the sheet,
wherein the identifying unit is configured to identify the type of the sheet as the envelope type sheet based on the size of the sheet.

12. The image forming apparatus according to claim 1 ,
wherein the time-counting unit is configured to re-count the conveyance time upon the conveyance unit being instructed to retry sheet conveyance, and
upon the conveyance time of the sheet counted after the conveyance unit is instructed to retry sheet conveyance being smaller than a second over stacking threshold value that is smaller than the first over stacking threshold value, the determination unit determines that over stacking has occurred.

13. The image forming apparatus according to claim 1 , further comprising:
an output unit configured to output over stacking information indicating that sheets are over-stacked, upon the determination unit determining that sheets are over-stacked in the stacking unit.

14. The image forming apparatus according to claim 13 , further comprising
a sheet-counting unit configured to count a number of consecutive sheets for which an event occurred after the determination unit determines that over stacking in the stacking unit has occurred, the event being an event where the conveyance time of a sheet conveyed from the stacking unit does not exceed the first over stacking threshold value,
wherein the output unit is further configured to stop outputting the over stacking information in a case that the number of consecutive sheets counted by the sheet-counting unit reaches a stop threshold.

15. The image forming apparatus according to claim 13 , further comprising
a detection unit configured to detect whether or not a sheet is stacked in the stacking unit,
wherein the output unit is further configured to stop outputting the over stacking information in a case that the detection unit detects that the sheet is not stacked in the stacking unit after the determination unit determines that over stacking in the stacking unit has occurred.

16. The image forming apparatus according to claim 13 , wherein
the output unit is further configured to stop outputting the over stacking information in a case that a type of the sheet stacked in the stacking unit changes after the determination unit determines that over stacking in the stacking unit has occurred.

17. The image forming apparatus according to claim 1 , further comprising:
a housing; and
a pull-out/push-in detection unit configured to detect pulling out and pushing in of the stacking unit from and to the housing
wherein the determination unit includes an over stacking determination unit configured to determine whether or not sheets are over-stacked in the stacking unit based on whether or not the conveyance time of a first sheet that is conveyed after the pull-out/push-in detection unit detects pulling out and pushing in of the stacking unit exceeds the first over stacking threshold value.

18. The image forming apparatus according to claim 17 , further comprising
an output unit configured to output over stacking information indicating that sheets are over-stacked, upon the determination unit determining that sheets are over-stacked in the stacking unit.

19. The image forming apparatus according to claim 18 , wherein
the output unit is further configured to stop outputting the over stacking information in a case that the over stacking determination unit determines that sheets are not over-stacked in the stacking unit after the over stacking determination unit determines that sheets are over-stacked in the stacking unit.

20. The image forming apparatus according to claim 18 , wherein
the output unit is further configured to stop outputting the over stacking information in a case that the pull-out/push-in detection uni

Assignees

• Canon Kk

Inventors

• Isobe Ken-Ichiro
• Sugano Michio

Classifications

• G03G2215/00383

  Cassette · CPC title

• B65H7/20

  Controlling associated apparatus · CPC title

• B65H2511/528

  Jam · CPC title

• B65H2513/53

  Operations & Transport · mapped topic

• B65H7/18 Primary

  Modifying or stopping actuation of separators · CPC title