FEEDER DEVICE FOR FEEDING MEDIA SHEETS

Abstract

A feeder device for feeding media sheets along a feed path, including: (a) an accommodator for accommodating the media sheets; (b) a feed mechanism including (b-1) a roller that is to be held in contact with the media sheets accommodated in the accommodator and (b-2) a motor that is controllable based on a variable so as to rotate the roller, so that the media sheets can be fed along the feed path by the roller; (c) a detector operable to detect an amount of rotation of the roller or the motor; (d) a controller operable to adjust the variable on the basis of the amount of rotation detected by the detector such that feed movement of each media sheet can be achieved substantially as desired; (e) a monitor operable to monitor the variable that is adjusted by the controller; and (f) a media-related information obtainer operable to obtain information related to the media sheets fed by the feed mechanism, based on the actual value of the adjusted variable monitored by the monitor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, advantages and technical and industrial significance of the present invention will be better understood by reading the following detailed description of presently preferred embodiment of the invention, when considered in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view showing a multifunction device 1 equipped with a sheet feeder 18 as a feeding device of the present invention:

FIG. 2 is a cross sectional view showing a main construction of a printer portion 2 of the multifunction device 1;

FIG. 3 is a plan view showing the printer portion 2 when a scanner portion 3 is removed from the multifunction device 1;

FIG. 4 is a set of views showing a sheet supply arm 26 that is inclined by an amount that varies depending upon a remaining amount of media sheets;

FIG. 5 is a block diagram showing a general construction of a main controller 60;

FIG. 6 is a block diagram showing a general construction of a motor controller 70;

FIG. 7 is a flow chart showing a routine carried out under control of a CPU 61;

FIG. 8 is a flow chart showing a sub-routine carried out under control of the CPU 61;

FIGS. 9A and 9B are views for showing a waveform (I₁(t)) representing, by way of example, a chronological change of an electric current I supplied to an electric motor when a sufficient amount of standard papers remain in a sheet supply tray 20;

FIGS. 10A and 10B are views for showing a waveform (I₂(t)) representing, by way of example, a chronological change of an electric current I supplied to the electric motor when no media sheet remains in the sheet supply tray 20;

FIGS. 11A and 11B are views for showing a waveform (I₃(t)) representing, by way of example, a chronological change of an electric current I supplied to the electric motor when no media sheet remains in the sheet supply tray 20 and a coefficient of friction of a surface of a sheet supply roller 25 is lowered;

FIGS. 12A and 12B are views for showing a waveform (I₄(t)) representing, by way of example, a chronological change of an electric current I supplied to the electric motor when the amount of standard papers remaining in the sheet supply tray 20 is small; and

FIG. 13A is a view for showing a waveform (I₅(t)) representing, by way of example, a chronological change of an electric current I supplied to the electric motor when a glossy paper as a final media sheet is fed;

FIG. 13B is a view for showing a waveform (I₆(t)) representing, by way of example, a chronological change of an electric current I supplied to the electric motor when a standard paper as a final media sheet is fed; and

FIG. 13C is a view for showing a waveform (I₇(t)) representing, by way of example, a chronological change of an electric current I supplied to the electric motor when a glossy paper is fed while a sufficient amount of glossy papers remain in the sheet supply tray 20.

Claims

1. A feeder device for feeding media sheets one after another along a feed path, comprising: (a) an accommodator capable of accommodating the media sheets stacked therein;(b) a feed mechanism including (b-1) a roller that is to be held in contact with the media sheets stacked in said accommodator and (b-2) an electric motor that is controllable based on a variable so as to rotate said roller, so that the media sheets can be fed along said feed path by said roller which is held in contact with the media sheets and which is rotated by said electric motor;(c) a detector operable to detect an amount of rotation of one of said roller and said electric motor;(d) a controller operable to adjust said variable on the basis of the amount of rotation detected by said detector such that feed movement of each of the media sheets along said feed path can be achieved substantially as desired;(e) a monitor operable to monitor an actual value of said variable that is adjusted by said controller; and(f) a media-related information obtainer operable to obtain information related to the media sheets fed by said feed mechanism, based on the actual value of the adjusted variable monitored by said monitor.

2. The feeder device according to claim 1, wherein said media-related information obtainer includes a media-type determiner operable to determine a type of the media sheets fed by said feed mechanism, based on the actual value of the adjusted variable monitored by said monitor.

3. The feeder device according to claim 2, wherein said media-type determiner determines the type of the media sheets fed by said feed mechanism, based on the actual value of said adjusted variable that is monitored in a stable stage of the feed movement of each of the media sheets in which said variable is held substantially constant.

4. The feeder device according to claim 2, further comprising a type-determination reference data storage storing a type-determination reference data indicative of a relationship between a reference value of said adjusted variable and the type of the media sheets to be fed by said feed mechanism, wherein said media-type determiner determines the type of the media sheets fed by said feed mechanism, based on the actual value of said adjusted variable monitored by said monitor and according to said type-determination reference data stored in said type-determination reference data storage.

5. The feeder device according to claim 2, further comprising: a friction element disposed in a bottom portion of said accommodator so as to be opposed to said roller, such that a friction acting between said friction element and a lowermost one of the media sheets is larger than a friction acting between the media sheets; anda finality-determination reference data storage storing a finality-determination reference data indicative of a reference value of said adjusted variable that is to be monitored when a currently fed one of the media sheets is a final sheet that is slid on said friction element so as to be fed along said feed path,wherein said media-type determiner determines also whether each of the media sheets is the final sheet, based on the actual value of said adjusted variable monitored by said monitor and according to said finality-determination reference data stored in said finality-determination reference data storage.

6. The feeder device according to claim 2, further comprising, in addition to said media-type determiner, a remaining-amount determiner that is operable to determine an amount of the media sheets remaining in said accommodator, based on the actual value of said adjusted variable monitored by said monitor in a registering stage of the feed movement of each of the media sheets in which each of the media sheets is registered.

7. The feeder device according to claim 6, further comprising a remaining-amount determination reference data storage storing a remaining-amount determination reference data indicative of a relationship between a reference value of said adjusted value and the amount of the media sheets remaining in said accommodator, wherein said remaining-amount determiner determines the amount of the media sheets remaining in said accommodator, based on the actual value of said adjusted variable monitored by said monitor and according to said remaining-amount determination reference data stored in said remaining-amount determination reference data storage.

8. The feeder device according to claim 2, further comprising, in addition to said media-type determiner, a media-presence determiner that is operable to determine whether at least one of the media sheets is present in said accommodator, based on the actual value of said adjusted variable monitored by said monitor and an upper threshold value of the adjusted variable.

9. The feeder device according to claim 8, wherein said media-presence determiner determines that none of the media sheets is present in said accommodator, when the actual value of said adjusted variable monitored by said monitor exceeds the upper threshold value.

10. The feeder device according to claim 2, further comprising, in addition to said media-type determiner, a checking-need determiner that is operable to determine whether a condition of said roller needs to be checked, wherein said checking-need determiner is operable, when none of the media sheets is present in said accommodator, to determine whether the condition of said roller needs to be checked, by detecting a slip motion of said roller on a friction element disposed in a bottom portion of said accommodator,and wherein said checking-need determiner detects the slip motion of said roller on said friction element, based on the actual value of said adjusted variable that is monitored by said monitor.

11. The feeder device according to claim 10, wherein said checking-need determiner detects the slip motion of said roller on said friction element, based on at least one of a time integral of the actual value of said adjusted variable and a time derivative of the actual value of said adjusted variable.

12. The feeder device according to claim 2, further comprising an indicator operable to indicate information related to result of determination made by said media-type determiner.

13. The feeder device according to claim 2, wherein said variable adjusted by said controller is a value related to an electric power that is supplied to said electric motor.

14. The feeder device according to claim 1, wherein said media-related information obtainer includes a remaining-amount determiner operable to determine an amount of the media sheets remaining in said accommodator, based on the actual value of the adjusted variable monitored by said monitor.

15. The feeder device according to claim 14, wherein said remaining-amount determiner determines a type of the media sheets fed by said feed mechanism, in addition to said amount of the media sheets remaining in said accommodator.

16. The feeder device according to claim 14, wherein said remaining-amount determiner determines said amount of the media sheets remaining in said accommodator, based on the actual value of said adjusted variable and also a type of the media sheets fed by said feed mechanism.

17. The feeder device according to claim 14, further comprising, in addition to said remaining-amount determiner as a first remaining-amount determiner that is operable to determine the amount of the media sheets remaining in said accommodator based on the actual value of said adjusted variable monitored by said monitor in a stable stage of the feed movement of each of the media sheets in which said variable is held substantially constant, a second remaining-amount determiner that is operable to determine the amount of the media sheets remaining in said accommodator, based on the actual value of said adjusted variable monitored by said monitor in a registering stage of the feed movement of each of the media sheets in which each of the media sheets is registered.

18. The feeder device according to claim 17, wherein one of said first remaining-amount determiner and said second remaining-amount determiner determines whether each of the media sheets is a final sheet that is slid on a bottom portion of said accommodator so as to be fed along said feed path,and wherein the other of said first remaining-amount determiner and said second remaining-amount determiner determines whether a number of the media sheets remaining in said accommodator is larger than a predetermined amount.

19. The feeder device according to claim 17, further comprising a remaining-amount determination reference data storage storing a remaining-amount determination reference data indicative of a relationship between a reference value of said adjusted variable and the amount of the media sheets remaining in said accommodator, wherein said second remaining-amount determiner determines the amount of the media sheets remaining in said accommodator, based on the actual value of said adjusted variable monitored by said monitor in said registering stage and according to said remaining-amount determination reference data stored in said remaining-amount determination reference data storage.

20. The feeder device according to claim 14, further comprising, in addition to said remaining-amount determiner, a media-presence determiner that is operable to determine whether at least one of the media sheets is present in said accommodator, based on the actual value of said adjusted variable monitored by said monitor and an upper threshold value of the adjusted variable.

21. The feeder device according to claim 20, wherein said media-presence determiner determines that none of the media sheets is present in said accommodator, when the actual value of said adjusted variable monitored by said monitor exceeds the upper threshold value.

22. The feeder device according to claim 14, further comprising, in addition to said remaining-amount determiner, a checking-need determiner that is operable to determine whether a condition of said roller needs to be checked, wherein said checking-need determiner is operated, when none of the media sheets is present in said accommodator, to determine whether the condition of said roller needs to be checked, by detecting a slip motion of said roller on a friction element disposed in a bottom portion of said accommodator,and wherein said checking-need determiner detects the slip motion of said roller on said friction element, based on the actual value of said adjusted variable that is monitored by said monitor.

23. The feeder device according to claim 22, wherein said checking-need determiner detects the slip motion of said roller on said friction element, based on at least one of a time integral of the actual value of said adjusted variable and a time derivative of the actual value of said adjusted variable.

24. The feeder device according to claim 14, further comprising an indicator operable to indicate information related to result of determination made by said remaining-amount determiner.

25. The feeder device according to claim 14, wherein said variable adjusted by said controller is a value related to an electric power that is supplied to said electric motor.