Title:
PAPER FEEDING DEVICE FOR IMAGE FORMING APPARATUS
Kind Code:
A1


Abstract:
An embodiment of the present invention relates to an image forming apparatus including: a control panel for designating a size of sheets fed by a paper feeding cassette; a sidewall motor that opens a front sidewall and a rear sidewall to the maximum when the paper feeding cassette is drawn out from an apparatus main body and slides the front sidewall and the rear sidewall to both side positions of the sheets of the designated size when the paper feeding cassette is inserted into the apparatus main body; and an end wall motor that opens an end wall to the maximum when the paper feeding cassette is drawn out from the apparatus main body and slides the end wall to a trailing end position of the sheets of the designated size when the paper feeding cassette is inserted into the apparatus main body.



Inventors:
Matsushima, Toshihiro (Shizuoka, JP)
Application Number:
12/363414
Publication Date:
08/06/2009
Filing Date:
01/30/2009
Assignee:
Kabushiki Kaisha Toshiba (Tokyo, JP)
Toshiba Tec Kabushiki Kaisha (Tokyo, JP)
Primary Class:
International Classes:
B65H1/00
View Patent Images:



Primary Examiner:
CICCHINO, PATRICK D
Attorney, Agent or Firm:
PATTERSON + SHERIDAN, L.L.P. (Houston, TX, US)
Claims:
What is claimed is:

1. A paper feeding device for an image forming apparatus comprising: a housing member that is inserted into and removed from an apparatus main body and stores recording media; a guide member that is slidably provided in the housing member and regulates a feeding position of the recording media to an image forming unit; and a driving member that slides the guide member according to a size of the recording median when the housing member is inserted into the apparatus main body.

2. The device according to claim 1, further comprising a detecting member that detects the size of the recording media.

3. The device according to claim 2, wherein the detecting member includes a pressure sensor that detects pressure to the guide member by the recording media.

4. The device according to claim 2, wherein the detecting member includes a photo-sensor.

5. The device according to claim 1, wherein the size of the recording media is set by the apparatus main body.

6. The device according to claim 5, wherein the size of the recording media is set by data input by from the apparatus main body.

7. The device according to claim 5, wherein the size of the recording media is set according to an inserting position of the housing member into the apparatus main body.

8. The device according to claim 1, wherein the driving member slides the guide member to an open position when the housing member is drawn out from the apparatus main body and slides the guide member to the feeding position when the housing member is inserted into the apparatus main body.

9. The device according to claim 1, wherein the guide member includes a side guide member that regulates a side of the recording media and an end guide member that regulates a trailing end of the recording media, and the driving member includes a first driving member that drives the side guide member and a second driving member that drives the end guide member.

10. An image forming apparatus comprising: an apparatus main body including an image forming unit; and a paper feeding device including a housing member that is inserted into and removed from an apparatus main body and stores recording media to be fed to the image forming unit, a guide member that is slidably provided in the housing member and regulates a feeding position of the recording media to the image forming unit and a driving member that slides the guide member according to a size of the recording media when the housing member is inserted into the apparatus main body.

11. The apparatus according to claim 10, wherein the paper feeding device further includes a detecting member that detects the size of the recording media.

12. The apparatus according to claim 11, wherein the detecting member includes a pressure sensor that detects pressure to the guide member by the recording media.

13. The apparatus according to claim 11, wherein the detecting member includes a photo-sensor.

14. The apparatus according to claim 10, wherein the apparatus main body further includes a setting member that sets the size of the recording media.

15. The apparatus according to claim 14, wherein the setting member includes an input unit that inputs the size of the recording media.

16. The apparatus according to claim 14, wherein the size of the recording media is set according to an inserting position of the paper feeding device into the apparatus main body.

17. The apparatus according to claim 10, wherein the driving member slides the guide member to an open position when the housing member is drawn out from the apparatus main body and slides the guide member to the feeding position when the housing member is inserted into the apparatus main body.

18. The apparatus according to claim 10, wherein the guide member includes a side guide member that regulates a side of the recording media and an end guide member that regulates a trailing end of the recording media, and the driving member includes a first driving member that drives the side guide member and a second driving member that drives the end guide member.

19. A sheet storing method for an image forming apparatus comprising: sliding a guide member to an open position by drawing out a housing member from an apparatus main body; and sliding the guide member to a storing position according to a size of a recording media by inserting the housing member into the apparatus main body.

20. The method according to claim 19, wherein the sliding the guide member to the storing position includes sliding to a storing position at a side of the recording media and sliding to a storing position at a trailing end of the recording media.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Provisional U.S. Application 61/026,681 filed on Feb. 6, 2008, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a paper feeding device for an image forming apparatus that stably feed sheets to an image forming unit of a copying machine or a multi-function peripheral.

BACKGROUND

There is a paper feeding cassette mounted on an image forming apparatus to feed sheets to an image forming unit. In this paper feeding cassette, both sides and trailing ends of sheets of various sizes are regulated by guides to prevent a tilt of the sheets.

In the paper feeding cassette in the past, after supplying sheets, an operator manually moves the guides to regulating positions according to a size of the sheets.

However, in the apparatus in the past in which the guides are manually moved, after supplying sheets into the paper feeding cassette, in some case, the operator forgets to move the guides or fails to move the guides to accurate regulating positions. When the sheets in the paper feeding cassette are not accurately regulated, the sheets skew when the sheets are taken out from the paper feeding cassette. As a result, it is likely that an image quality is deteriorated and a sheet jam occurs.

Therefore, there is a demand for a paper feeding device for an image forming apparatus that can surely move, when sheets are set in a paper feeding cassette, guides to regulating positions according to a size of the sheets, prevent the sheets from skewing, prevent a sheet jam from occurring, and realize improvement of an image quality.

SUMMARY

According to an aspect of the present invention, an image quality is improved through improvement of performance for feeding sheets to an apparatus main body and a sheet jam is prevent from occurring.

According to the aspect, there is provided a paper feeding device for an image forming apparatus including: a housing member that is inserted into and removed from an apparatus main body and stores recording media; a guide member that is slidably provided in the housing member and regulates a feeding position of the recording media to an image forming unit; and a driving member that slides the guide member according to a size of the recording media when the housing member is inserted into the apparatus main body.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a copying machine according to a first embodiment of the present invention;

FIG. 2 is a schematic top view of a paper feeding cassette according to the first embodiment;

FIG. 3 is a schematic diagram for explaining driving of sidewalls and an end wall of the paper feeding cassette according to the first embodiment;

FIG. 4 is a schematic top view of stop positions of the sidewalls and the end wall of the paper feeding cassette according to the first embodiment;

FIG. 5 is a schematic diagram for explaining supply of sheets into the paper feeding cassette according to the first embodiment; and

FIG. 6 is a schematic top view of a paper feeding cassette according to a third embodiment of the present invention.

DETAILED DESCRIPTION

A first embodiment of the present invention is explained below.

FIG. 1 is a schematic diagram of a copying machine 1 as an image forming apparatus according to the first embodiment. The copying machine 1 includes a scanner unit 13 that scans an image, a printer unit 14 that forms an image, a paper feeding unit 21 as a paper feeding device including an upper paper feeding cassette 21a, a lower paper feeding cassette 21b, and a large capacity cassette 21c for feeing sheets P as a recording medium, and a paper discharging unit 70 including a first tray 71 and a second tray 72 for accumulating the sheets P discharged from the printer unit 14 as an image forming unit. A control panel 102 as an input unit supported by a pole 101 is provided in an apparatus main body 11 that configures an outer hull of the copying machine 1. A manual paper feeding unit 23 is provided on a side of the apparatus main body 11. A conveying path 40 for the sheets P is provided in a route leading from the paper feeding unit 21 or the manual paper feeding unit 23 to the paper discharging unit 70 through the printer unit 14 of the copying machine 1.

The scanner unit 13 scans an object having image information (hereinafter referred to as original document) fed from an auto document feeder (ADF) 35 and capture the image information as image data. After the scanner unit 13 finishes scanning the image information, the ADF 35 discharges the original document to a document discharging unit 31.

The printer unit 14 forms, on the sheet P, an image corresponding to inputted image information or the image information scanned by the scanner unit 13. The printer unit 14 includes photoconductive drums 41, charging devices 48 that uniformly charge the photoconductive drums 41, an exposing device 42 that forms electrostatic latent images on the photoconductive drums 41, developing devices 43 that develop the electrostatic latent images formed on the photoconductive drums 41, and a transfer device 44 that transfers toner images developed on the photoconductive drums 41 onto the sheets P of arbitrary sizes. The transfer device 44 includes a transfer belt 44a and a secondary transfer roller 44b. The printer unit 14 further includes a fixing device 45 that fixes the toner images on the sheet P having the toner images transferred thereon by the transfer device 44. The fixing device 45 includes a fixing roller 46 and a press roller 47.

The conveying path 40 includes conveying rollers 24 and registration rollers 16 for feeding the sheet P taken out from the paper feeding unit 21 or the manual paper feeding unit 23 by a pickup roller 22 to the transfer device 44. The conveying path 40 conveys the sheet P having the fixed toner images to the paper discharging unit 70 through the transfer device 44 and the fixing device 45.

The paper discharging unit 70 includes a paper discharging and conveying path 60 that discharges the sheet P to the first tray 71 or the second tray 72 or reverses the sheet P. The paper discharging and conveying path 60 includes a lower conveying path 61 and an upper conveying path 62. A first gate 63 divides the lower conveying path 61 and the upper conveying path 62. The lower conveying path 61 reaches the first tray 71 through a first paper discharge roller 18. The upper conveying path 62 includes a second conveying path 52 on an upper side and a third conveying path 53 on a lower side. A second gate 67 divides the second conveying path 52 and the third conveying path 53.

The second conveying path 52 reaches the second tray 72 through a second paper discharge roller 19. The third conveying path 53 is a reversing and retracting path for the sheet P. The third conveying path 53 includes a reversing and conveying roller 68. When a trailing end of the sheet P conveyed to the third conveying path 53 passes the first gate 66, the reversing and conveying roller 68 rotates in the opposite direction. The reversing and conveying roller 68 rotates in the opposite direction to reversely convey the sheet P from the third conveying path 53 in the direction of a circulating path 50. The circulating path 50 feeds the sheet P to the transfer device 44 again.

The upper paper feeding cassette 21a and the lower paper feeding cassette 21b of the paper feeding unit 21 have the same structure. As shown in FIG. 2, each of the upper paper feeding cassette 21a and the lower paper feeding cassette 21b includes a case 78 as a housing member that stores the various sheets P and is inserted into and removed from the apparatus main body 11 and a front sidewall 80f and a rear sidewall 80r as side guide members that are slidably provided in the case 78 and regulate both sides of the various sheets P. Further, each of the upper paper feeding cassette 21a and the lower paper feeding cassette 21b includes an end wall 81 as an end guide member that is slidably provided in the case 78 and regulates trailing ends of the various sheets P. The case 78 can be drawn out to a front side relative to the apparatus main body 11. The case 78 has on a rear side thereof a connector 78a for connecting the case 78 to an upper input and output terminal 11a or a lower input and output terminal 11b of the apparatus main body 11 when the case 78 is inserted into the apparatus main body 11. A tray-up sheet metal 82 that supports the sheets P is provided on a bottom surface of the case 78.

The front sidewall 80f and the rear sidewall 80r slide in an arrow “m” direction or an arrow “n” direction along a guide shaft 78b fixed to the bottom surface of the case 78. The end wall 81 slides in an arrow “s” direction or an arrow “t” direction along a slit 78c formed in the bottom surface of the case 78.

As shown in FIG. 3, a front ladder 83f is provided in the front sidewall 80f. A rear ladder 83r is provided in the rear sidewall 80r. The front ladder 83f and the rear ladder 83r engage with a gear 87 driven by a sidewall motor 86. The front ladder 83f, the rear ladder 83r, the sidewall motor 86, and the gear 87 configure a driving member. When the gear 87 rotates in an arrow “v” direction, the front sidewall 80f is slid in the arrow “n” direction by the front ladder 83f and the rear sidewall 80r is slid in the arrow “m” direction by the rear ladder 83r. When the gear 87 rotates in an arrow “w” direction, the front sidewall 80f is slid in the arrow “m” direction by the front ladder 83f and the rear sidewall 80r is slid in the arrow “n” direction by the rear ladder 83r.

The end wall 81 is slid by an end wall driving mechanism 84 as a driving member. The end wall driving mechanism 84 includes a conveyor belt 88 that reciprocatingly conveys the end wall 81 and an end wall motor 90 that reciprocatingly rotates the conveyor belt 88. When the connector 78a is connected to the input and output terminal 11a or the input and output terminal 11b, the sidewall motor 86 and the end wall motor 90 are connected to a CPU 110 that controls the entire copying machine 1. The sidewall motor 86 and the end wall motor 90 are controlled to be driven by the CPU 110.

The paper feeding cassette 21a or the paper feeding cassette 21b is drawn out from the apparatus main body 11 to disconnect the connector 78a from the input and output terminal 11a or the input and output terminal 11b of the apparatus main body 11. The sidewall motor 86 drives in the arrow “w” direction to slide the front sidewall 80f in the arrow “m” direction and open the front sidewall 80f to the maximum and stops the front sidewall 80f in a sheet supply position. Further, the sidewall motor 86 slides the rear sidewall 80r in the arrow “n” direction to open the rear sidewall 80r to the maximum and stops the rear sidewall 80r in a sheet supply position. When the front sidewall 80f and the rear sidewall 80r are present in the sheet supply positions, a distance between the sidewalls 80f and 80r is larger than the width of largest sheets stored in the paper feeding cassette 21a or 21b.

When the connector 78a is disconnected from the input and output terminal 11a of the apparatus main body 11, the end wall motor 90 rotates the conveyor belt 88 in the arrow “t” direction and slides the end wall 81 in the arrow “t” direction. The end wall motor 90 opens the end wall 81 to the maximum and stops the end wall 81 in a sheet supply position on a rear end side of the case 78. When the end wall 81 is present in the sheet supply position, a distance from a distal end 78d of the case 78 to the end wall 81 is larger than the length of the largest sheets stored in the paper feeding cassette 21a or 21b. Opening the front sidewall 80f, the rear sidewall 80r, or the end sidewall 81 to the maximum, means the sidewall is opened to a slide limit in the case 78.

When the paper feeding cassette 21a or 21b is inserted into the apparatus main body 11 and the connector 78a is connected to the input and output terminal 11a of the apparatus main body 11, the sidewall motor 86 drives in the arrow “v” direction to close the front sidewall 80f and the rear sidewall 80r according to a size of sheets in the paper feeding cassette 21a or 21b. When the number of revolutions of the sidewall motor 86 reaches the number of revolutions set according to the size of the sheets in the paper feeding cassette 21a or 21b, the sidewall motor 86 stops the driving. When the sidewall motor 86 stops, the distance between the front sidewall 80f and the rear sidewall 80r coincides with the width of the sheets stored in the paper feeding cassette 21a or 21b. The front sidewall 80f and the rear sidewall 80r regulate both sides in the width direction of the sheets P in the paper feeding cassette 21a or 21b.

When the connector 78a is connected to the input and output terminal 11a of the apparatus main body 11, the end wall motor 90 rotates the conveyor belt 88 in the arrow “s” direction to slide the end wall 81 in the arrow “s” direction and closes the end wall 81 according to the size of the sheets in the paper feeding cassette 21a or 21b. When the number of revolutions of the end wall motor 90 reaches the number of revolutions set according to the size of the sheets in the paper feeding cassette 21a or 21b, the end wall motor 90 stops the driving. When the end wall motor 90 stops, the end wall 81 regulates the trailing end of the sheets P in the paper feeding cassette 21a or 21b.

The control panel 102 includes a display unit 102a and a keyboard 102b. The control panel 102 has an input function for inputting conditions for image formation by the copying machine 1, start of the image formation, start of image scanning by the scanner unit 13, and the like to the CPU 110. The control panel 102 has a display function and the like for performing display of a confirmation screen for inputted information and the like and display of a down state and the like of the copying machine 1. The control panel 102 displays insertion and removal of the paper feeding cassettes 21a and 21b into and from the apparatus main body 11. A user designates, on the control panel 102, sizes of the sheets P stored in the paper feeding cassettes 21a and 21b.

The user designates, on the control panel 102, a size of the sheets P stored in the upper paper feeding cassette 21a as, for example, the A4 landscape size in the JIS standard. The CPU 110 outputs a signal for storing the sheets P of the A4 landscape size in a correct position to the upper input and output terminal 11a. The sidewall motor 86 and the end wall motor 90 of the upper paper feeding cassette 21a drive, according to the signal from the upper input and output terminal 11a, to store the sheets P of the A4 landscape size in the correct position in the case 78. The user designates, on the control panel 102, a size of the sheets P stored in the lower paper feeding cassette 21b as, for example, the A3 size in the JIS standard. The CPU 110 outputs a signal for storing the sheets P of the A3 size in a correct position to the lower input and output terminal 11b. The sidewall motor 86 and the end wall motor 90 of the lower paper feeding cassette 21b drive, according to the signal from the lower input and output terminal 11b, to store the sheets P of the A3 size in the correct position in the case 78.

The user instructs, on the control panel 102, the copying machine 1 to form an image on the sheets P. The upper paper feeding cassette 21a stores, for example, the sheets P of the A4 landscape size in the JIS standard as shown in FIG. 4 according to the instruction from the control panel 102. When the upper paper feeding cassette 21a is inserted into the apparatus main body 11 (the connector 78a is connected to the upper input and output terminal 11a), the sidewall motor 86 drives and the front sidewall 80f and the rear sidewall 80r slide to positions for regulating both the sides of the sheets P and stop. The end wall motor 90 drives and the end wall 81 is slid to a position for regulating the trailing end of the sheets P and stops (indicated by a solid line in FIG. 4). The lower paper feeding cassette 21b stores, for example, the sheets P of the A3 size in the JIS standard according to the instruction from the control panel 102.

According to the instruction for image formation, the charging device 48 charges the photoconductive drum 41. The exposing device 42 outputs image light (exposure light) corresponding to image data that should be formed as an image on the charged photoconductive drum 41. The exposing device 42 irradiates the exposure light on the photoconductive drum 41 to form an electrostatic latent image corresponding to the exposure light thereon. The electrostatic latent image formed on the photoconductive drum 41 is developed with a toner by the developing device 43 and visualized. A toner image obtained by visualizing the electrostatic latent image on the photoconductive drum 41 is transferred onto the sheet P by the transfer device 44. The sheet P is fed from the paper feeding unit 21 or the manual paper feeding unit 23 and conveyed through the conveying path 40 and reaches the transfer device 44. The toner image transferred onto the sheet P is fixed on the sheet P by the fixing device 45. The sheet P having the toner image fixed thereon is conveyed to the paper discharging and conveying path 60. The sheet P is discharged to the first tray 71 or the second tray 72 through the paper discharging and conveying path 60 or conveyed to the transfer device 44 again through the circulating path 50.

While the designated image formation is carried out, for example, if the sheets P in the upper paper feeding cassette 21a are exhausted, the control panel 102 displays, on the display panel 102a, a message for urging supply of the sheets P into the upper paper feeding cassette 21a. For the supply of the sheets P, the user draws out the upper paper feeding cassette 21a from the apparatus main body 11. When the user draws out the upper paper feeding cassette 21a and disconnects the connector 78a of the case 78 from the upper input and output terminal 11a of the apparatus main body 11, the sidewall motor 86 drives in the arrow “w” direction. The front sidewall 80f slides in the arrow “m” direction to a position indicated by a dotted line in FIG. 4. The rear sidewall 80r slides in the arrow “n” direction to a position indicated by a dotted line in FIG. 4. The front sidewall 80f and the rear sidewall 80r open to maximum positions. The end wall motor 90 rotates the conveyor belt 88 in the arrow “t” direction. The end wall 81 slides in the arrow “t” direction to a position indicated by a dotted line in FIG. 4 and opens to a maximum position.

In a state in which the front sidewall 80f, the rear sidewall 80r, and the end wall 81 are open to the maximum, the user supplies the sheets P of the A4 size into the case 78 of the upper paper feeding cassette 21a. When the sheets P are supplied into the case 78, the sheets P may out of alignment as shown in FIG. 5. Even if some of the sheets P are not aligned, after supplying the sheets P into the case 78, the user directly inserts the upper paper feeding cassette 21a into the apparatus main body 11.

When the user inserts the upper paper feeding cassette 21a into the apparatus main body 11 and connects the connector 78a of the case 78 to the upper input and output terminal 11a of the apparatus main body, the sidewall motor 86 drives in the arrow “v” direction. The front sidewall 80f and the rear sidewall 80r slide from the maximum open state to positions for regulating both the sides of the sheets P of the A4 landscape size and stops in a position indicated by a solid line in FIG. 4. The sheets P that are not aligned during the supply into the case 78 come into contact with the front sidewall 80f and the rear sidewall 80r to be regulated on both the sides thereof. Both the sides of the sheets P in the case 78 are aligned in A4 landscape size positions.

When the user connects the connector 78a of the case 78 to the upper input and output terminal 11a of the apparatus main body 11, the end wall motor 90 rotates the conveyor belt 88 in the arrow “s” direction. The end wall 81 slides from the maximum open state to a position for regulating the trailing end of the sheets P of the A4 landscape size and stops in a position indicated by a solid line in FIG. 4. The sheets P that are not aligned during the supply into the case 78 come into contact with the end wall 81 to be regulated at the trailing end thereof. The trailing end of the sheets P in the case 78 is aligned in an A4 landscape size position. The out of alignment of the sheets P is corrected in the upper paper feeding cassette 21a. The sheets P are supplied in a state aligned in a correct paper feeding position of the A4 landscape size.

When the user supplies the sheets P into the lower paper feeding cassette 21b instructed to store the sheets P of the A3 size, the user supplies the sheets P in the same manner as the supply of the sheets P into the upper paper feeding cassette 21a. The user draws out the lower paper feeding cassette 21b from the apparatus main body 11. When the user disconnects the connector 78a of the case 78 from the lower input and output terminal 11b of the apparatus main body 11, the sidewall motor 86 is drove to slide the front sidewall 80f and the rear sidewall 80r from positions for regulating the sheets P of the A3 size to the maximum open positions. The end wall motor 90 drives to slide the end wall 81 from a position for regulating the sheets P of the A3 size to the maximum open position.

The user supplies the sheets P of the A3 size into the lower paper feeding cassette 21b. After supplying the sheets P, the user inserts the lower paper feeding cassette 21b into the apparatus main body 11. When the user connects the connector 78a of the case 78 to the lower input and output terminal 11b of the apparatus main body 11, the sidewall motor 86 is drove. The front sidewall 80f and the rear sidewall 80r slide from the maximum open state to positions for regulating both the ends of the sheets P of the A3 size and stop. The end wall motor 90 is drove and the end wall 81 slides from the maximum open state to a position for regulating the trailing end of the sheets P of the A3 size and stops.

In a state in which the lower paper feeding cassette 21b is inserted in the apparatus main body 11, the front sidewall 80f and the rear sidewall 80r are in contact with both the sides of the sheets P of the A3 size. The sheets P that are not aligned during the supply are regulated on both the sides by the front sidewall 80f and the rear sidewall 80r. Both the sides are aligned in A3 size positions. The end wall 81 comes into contact with the trailing end of the sheets P. The sheets P that are not aligned during the supply are regulated at the trailing end thereof by the end wall 81. The trailing end is aligned in an A3 size position. In the lower paper feeding cassette 21b, the sheets P are supplied in a correct paper feeding position of the A3 size.

In this embodiment, a size of the sheet P designated by the user on the control panel 102 is not limited. The size may be the B4 size in the JIS standard, the Legal size, the Letter size, or the Ledger size of the US standard, or the like. When the user changes a size of the sheet P in the paper feeding cassette 21a or 21b, the user selects the upper paper feeding cassette 21a or the lower paper feeding cassette 21b on the control panel 102. The user inputs a size of the sheets P fed from the selected paper feeding cassette 21a or 21b and determines the change of the size, on the control panel 102. According to information inputted on the control panel 102, the CPU 110 outputs a signal for storing the sheets P of the changed size in a correct position to the upper input and output terminal 11a or the lower input and output terminal 11b.

In this embodiment, the user disconnects the connector 78a from the input and output terminal 11a or the input and output terminal 11b of the apparatus main body 11 and opens the front sidewall 80f, the rear sidewall 80r, or the end sidewall 81 to the maximum. However, the present invention is not limited to this. The front sidewall 80f, the rear sidewall 80r, or the end sidewall 81 may be opened in a range in which the user can easily supply the sheets P.

According to the first embodiment, in supplying the sheets P into the paper feeding cassette 21a or 21b, the user draws out the upper paper feeding cassette 21a or the lower paper feeding cassette 21b from the apparatus main body 11. Then, the sidewall motor 86 slides the front sidewall 80f and the rear sidewall 80r to the maximum open positions. The end wall motor 90 slides the end wall 81 to the maximum open position. When the user supplies the sheets P into the case 78, the front sidewall 80f, the rear sidewall 80r, or the end wall 81 is not an obstacle. The user can easily supply the sheets P.

According to the first embodiment, the sheets P are supplied into the case 78 and the upper paper feeding cassette 21a or the lower paper feeding cassette 21b is inserted in the apparatus main body 11. Then, the sidewall motor 86 slides the front sidewall 80f and the rear sidewall 80r to positions corresponding to the width of the size designated by the user on the control panel 102. The end wall motor 90 slides the end wall 81 to a position corresponding to the trailing end of the sheets P of the size designated by the user on the control panel 102. The out of alignment of the sheets P that occurs during the supply is corrected by inserting the upper paper feeding cassette 21a or the lower paper feeding cassette 21b into the apparatus main body 11. The sheets P can be stored in a correct paper feeding position. The paper feeding cassette 21a or 21b can feed the sheets P in a proper position. It is possible to easily align the leading end of the sheets P in the position of the registration rollers 16, prevent a positional shift of an image due to the out of alignment of the sheet P, and improve an image quality.

According to the first embodiment, after supplying the sheets P, the user does not have to operate the front sidewall 80f, the rear sidewall 80r, or the end wall 81. The user can easily supply the sheets P. After the supply of the sheets P into the case 78, the user does not forget to reset the front sidewall 80f, the rear sidewall 80r, or the end wall 81 to the position for regulating the sheets P. It is possible to prevent a paper jam due to the failure to reset the front sidewall 80f, the rear sidewall 80r, or the end wall 81.

According to the first embodiment, the user can change a size of the sheets P in the paper feeding cassette 21a or 21b on the control panel 102. It is easy to change the size of the sheets P in the paper feeding cassette 21a or 21b.

A copying machine according to a second embodiment of the present invention is explained below. In the second embodiment, a size of sheets stored in the paper feeding cassette in the first embodiment is designated for each of inserting positions in the apparatus main body (e.g., when the paper feeding cassette is inserted into an upper part of the apparatus main body, the size is designated as the A4 landscape size and, when the paper feeding cassette is inserted into a lower part thereof, the size is designated as the A3 size) Otherwise, the second embodiment is the same as the first embodiment. Concerning components same as those in the first embodiment, the explanation in the first embodiment applies in the second embodiment.

In the second embodiment, for example, the upper input and output terminal 11a of the apparatus main body 11 is controlled by the CPU 110 and outputs a signal for always storing the sheets P of the A4 landscape size in a correct position. The lower input and output terminal 11b is controlled by the CPU 110 and outputs a signal for always storing the sheets P of the A3 size in a correct position.

When the sheets P in the upper paper feeding cassette 21a or the lower paper feeding cassette 21b are exhausted, for example, the display panel 102a displays a message for urging supply of the sheets P. To supply the sheets P, the user draws out the upper paper feeding cassette 21a or the lower paper feeding cassette 21b from the apparatus main body 11 according to the message. For example, when the user draws out the upper paper feeding cassette 21a and disconnects the connector 78a of the case 78 from the upper input and output terminal 11a of the apparatus main body 11, the front sidewall 80f and the rear sidewall 80r are opened to the maximum positions by the sidewall motor 86. The end wall 81 is opened to the maximum position by the end wall motor 90.

The user supplies the sheets P of the A4 size into the case 78 of the upper paper feeding cassette 21a. Even if some of the sheets P are not aligned in the case 78, the user directly inserts the upper paper feeding cassette 21a into the apparatus main body 11. When the user connects the connector 78a of the case 78 to the upper input and output terminal 11a of the apparatus main body, the front sidewall 80f and the rear sidewall 80r are slid by the sidewall motor 86. The front sidewall 80f and the rear sidewall 80r slide from the maximum open state to the positions for regulating both the ends of the sheets P of the A4-landscape size and stop. Both the sides of the sheets P in the case 78 are aligned in the A4 landscape size positions.

The end wall 81 is slid by the end wall motor 90. The end wall 81 slides from the maximum open state to the position for regulating the trailing end of the sheets P of the A4 landscape size and stops. The trailing end of the sheets P in the case 78 is aligned in the A4 landscape size position. The out of alignment of the sheets P is corrected in the upper paper feeding cassette 21a. The sheets P are stored in a state aligned in the correct paper feeding position of the A4 landscape size. Supply of the sheets P into the lower paper feeding cassette 21b is performed in the same manner as the supply of the sheets P into the upper paper feeding cassette 21a.

In the second embodiment, a size of the sheets P designated for each of inserting positions in the apparatus main body 11 is not limited. The size of the sheets P for each of the inserting positions in the apparatus main body 11 is changed, for example, during maintenance by a serviceperson. An output signal from the upper input and output terminal 11a or the lower input and output terminal 11b is changed during the maintenance.

According to the second embodiment, when the user supplies the sheets P into the case 78, the front sidewall 80f, the rear sidewall 80r, or the end wall 81 are open to the maximum. The front sidewall 80f, the rear sidewall 80r, or the end wall 81 is not an obstacle. The user can easily supply the sheets P.

According to the second embodiment, after the supply of the sheets P, the out of alignment of the sheets P that occurs during the supply is corrected by inserting the paper feeding cassette 21a or 21b into the apparatus main body 11. The sheets P can be stored in a correct paper feeding position. The paper feeding cassette 21a or 21b can feed the sheets P in a proper position. It is possible to prevent a positional shift of an image due to the out of alignment of the sheet P and improve an image quality.

According to the second embodiment, after the supply of the sheets P, the user does not forget to reset the front sidewall 80f, the rear sidewall 80r, or the end wall 81 to the position for regulating the sheets P. It is possible to prevent a paper jam due to the failure to reset the front sidewall 80f, the rear sidewall 80r, or the end wall 81.

A copying machine according to a third embodiment of the present invention is explained below. In the third embodiment, a size of sheets stored in the paper feeding cassette is detected and the guide member is slid in the first embodiment. Otherwise, the third embodiment is the same as the first embodiment. Concerning components same as those in the first embodiment, the explanation in the first embodiment applies in the third embodiment.

In the third embodiment, as shown in FIG. 6, for example, the rear sidewall 80r and the end wall 81 respectively include a side pressure sensor 91 and an end pressure sensor 92 as detecting members on surfaces that come into contact with the sheets P. The side pressure sensor 91 or the end pressure sensor 92 detects pressure caused by the contact with the sheets P on the rear sidewall 80r or the end wall 81. Detection results of the side pressure sensor 91 and the end pressure sensor 92 are inputted to the CPU 110 from the connector 78a and the input and output terminals 11a and 11b.

A first photo-sensor 93a and a second photo-sensor 93b as detecting members that detect, for example, the rear sidewall 80r are provided on the bottom surface of the case 78. The first photo-sensor 93a detects that the rear sidewall 80r reaches the A4 landscape size position. The second photo-sensor 93b detects that the rear sidewall 80r reaches the B4 size position.

Third to fifth photo-sensors 94a, 94b, and 94c as detecting members that detect, for example, the end wall 81 are provided on the bottom surface of the case 78. The third photo-sensor 94a detects that the end wall 81 reaches the A4 landscape size position. The fourth photo-sensor 94b detects that the end wall 81 reaches the B4 size position. The fifth photo-sensor 94c detects that the end wall 81 reaches the A3 size position. Detection results of the first to fifth photo-sensors 93a, 93b, 94a, 94b, and 94c are inputted to the CPU 110 from the connector 78a and the input and output terminals 11a and 11b.

The CPU 110 stores, in a memory 110a, a pressure (α) caused on the front sidewall 80f and a pressure (β) caused on the end wall 81 when, for example, the sheets P in 500 sheet units are aligned in the case 78. The memory 110a stores size of the sheets P correspond to driving times of the sidewall motor 86, when a detection result (pressure) of the side pressure sensor 91 run to the pressure (α). The memory 110a stores size of the sheets P correspond to driving times of the end wall motor 90, when a detection result (pressure) of the end pressure sensor 92 run to the pressure (β).

When the sheets P in the upper paper feeding cassette 21a or the lower paper feeding cassette 21b are exhausted, for example, the display panel 102a displays a message for urging supply of the sheets P. To supply the sheets P, the user draws out the upper paper feeding cassette 21a or the lower paper feeding cassette 21b from the apparatus main body 11 according to the message. For example, when the user draws out the upper paper feeding cassette 21a and disconnects the connector 78a of the case 78 from the upper input and output terminal 11a of the apparatus main body 11, the front sidewall 80f and the rear sidewall 80r are opened to the maximum positions by the sidewall motor 86. The end wall 81 is opened to the maximum position by the end wall motor 90.

For example, the user supplies 500 pieces of the sheets P of the A4 size into the upper paper feeding cassette 21a. Even if some of the sheets P are not aligned in the case 78, the user directly inserts the upper paper feeding cassette 21a into the apparatus main body 11. When the connector 78a of the case 78 is connected to the upper input and output terminal 11a of the apparatus main body 11, the front sidewall 80f and the rear sidewall 80r are started to slide by the sidewall motor 86. When the rear sidewall 80r slides in the arrow “m” direction from the maximum open state, the rear sidewall 80r comes into contact with the sheets P. The side pressure sensor 91 inputs a detection result (pressure) caused by the contact with the sheets P to the CPU 110. The CPU 110 detects the driving times of the sidewall motor 86, when a detection result of the side pressure sensor 91 coincide with the pressure (α). The CPU 110 reads a size of sheets correspond to the driving times of the sidewall motor 86 in the memory 110a.

When the user connects the connector 78a of the case 78 to the upper input and output terminal 11a of the apparatus main body, the end wall 81 is started to slide by the end wall motor 90. When the end wall 81 slides in the arrow “s” direction from the maximum open state, the end wall 81 comes into contact with the trailing end of the sheets P. The end pressure sensor 92 inputs a detection result (pressure) caused by the contact with the sheets P to the CPU 110. The CPU 110 detects the driving times of the end wall motor 90, when a detection result of the end pressure sensor 92 coincide with the pressure (β) The CPU 110 reads a size of sheets correspond to the driving times of the end wall motor 90 in the memory 110a.

The CPU 110 performs matching of the size of the sheets obtained from the detection result of the size pressure sensor 91 and the size of the sheets obtained from the detection result of the end pressure sensor 92 and determines a size of the sheets P supplied into the case 78. When the CPU 110 determines that the sheet size is the A4 landscape size, the CPU 110 stops the sidewall motor 86 according to detection of the rear sidewall 80r by the first photo-sensor 93a. The CPU 110 stops the end wall motor 90 according to detection of the end wall 81 by the third photo-sensor 94a.

In the case 78, the sheets P come into contact with the front sidewall 80f and the rear sidewall 80r stopped in a detection position of the first photo-sensor 93a and the end wall 81 stopped in a detection position of the third photo-sensor 94a. The sheets P are regulated by the front sidewall 80f, the rear sidewall 80r, and the end wall 81, whereby the out of alignment of the sheets P caused during the supply is corrected. The sheets P are supplied in a state aligned in the correct paper feeding position of the A4 landscape size in the upper paper feeding cassette 21a. Supply of the sheets P into the lower paper feeding cassette 21b is performed in the same manner as the supply of the sheets P into the upper paper feeding cassette 21a.

In the third embodiment, a size of the sheets P supplied to the paper feeding cassette 21a or 21b is not limited.

After the size of the sheets P is determined, a photo-sensor does not have to be used for detection of a stop position of the front sidewall 80f, the rear sidewall 80r, or the end wall 81. Driving times to the stop position of the sidewall motor 86 and the end wall motor 90 corresponding to sizes of the sheets P may be set in advance to determine the stop position of the front sidewall 80f, the rear sidewall 80r, or the end wall 81.

In the third embodiment, a size of the sheets P designated for each of the inserting positions of the apparatus main body 11 is not limited. When a size of the sheets P supplied into the paper feeding cassette 21a or 21b is changed, the CPU 110 detects the driving times of the sidewall motor 86, when a detection result of the side pressure sensor 91 coincide with the pressure (α) or the driving times of the end wall motor 90, when a detection result of the end pressure sensor 92 coincide with the pressure (β). The CPU 110 reads a size of sheets correspond to the driving times of the sidewall motor 86 and the end wall motor 90.

According to a size of sheets, when the first or the second photo-sensors 93a, 93b detects the rear sidewall 80r reaches the position for regulating the sheets P, the CPU 110 stops the sidewall motor 86. According to a size of sheets, when any one of the third to fifth photo-sensors 94a, 94b, and 94c detects the end wall 81 reaches the position for regulating the sheets P, the CPU 110 stops the end wall motor 90. The front sidewall 80f, the rear sidewall 80r, or the end wall 81 can correct the out of alignment of the sheets P of a size corresponding to the size of the sheets and supply the sheets P into the paper feeding cassette 21a or 21b in a state aligned in a correct paper feeding position.

According to the third embodiment, when the user supplies the sheets P into the case 78, the front sidewall 80f, the rear sidewall 80r, or the end wall 81 are open to the maximum. The front sidewall 80f, the rear sidewall 80r, or the end wall 81 is not an obstacle. The user can easily supply the sheets P.

According to the third embodiment, after the supply of the sheets P, the out of alignment of the sheets P that occurs during the supply is corrected by inserting the paper feeding cassette 21a or 21b into the apparatus main body 11. The sheets P can be stored in a correct paper feeding position. The paper feeding cassette 21a or 21b can feed the sheets P in a proper position. It is possible to prevent a positional shift of an image due to the out of alignment of the sheet P and improve an image quality.

According to the third embodiment, after the supply of the sheets P, the user does not forget to reset the front sidewall 80f, the rear sidewall 80r, or the end wall 81 to the position for regulating the sheets P. It is possible to prevent a paper jam due to the failure to reset the front sidewall 80f, the rear sidewall 80r, or the end wall 81.

According to the third embodiment, it is possible to determine a size of the sheets P supplied into the case 78 using an output of the side pressure sensor 91 and the end pressure sensor 92.

The present invention is not limited to the embodiments. Various modifications are possible without departing from the spirit of the present invention. For example, the number of paper feeding devices mounted on and removed from the apparatus main body of the image forming apparatus and a size of recording media are not limited. A driving source on the apparatus main body side may be used for the driving member that slides the guide member. The image forming apparatus may be an image forming apparatus that forms an image on the basis of data from a computer terminal. A setting member may be an input unit of the computer terminal.