Patent Application
20110215518
Embodiments described herein relate generally to an image forming apparatus in which sheet remaining at the time of pulling out a sheet cassette is prevented.
At present, in a sheet cassette inserted in an image forming apparatus, a structure including a tray for stacking a sheet bundle and a pair of side walls to regulate the position of the sheet bundle in the width direction is mainstream. The sheet cassette further includes a coupling member (shaft+pin). When the sheet cassette is inserted in the inside of the image forming apparatus, the coupling member is inserted in a drive unit (coupling) fixed in the image forming apparatus and is coupled. The drive unit raises the tray to a position where the uppermost sheet of the sheet bundle stacked on the tray contacts a paper feed roller.
On the other hand, when the sheet cassette is pulled out from the inside of the image forming apparatus, there is a possibility that the uppermost sheet of the sheet bundle is placed in the state in which the sheet contacts the paper feed roller or is pinched. In this case, a friction force is exerted on the uppermost sheet by the paper feed roller. While the sheet cassette is pulled out from the inside of the image forming apparatus, the uppermost sheet is forced to remain in the inside of the image forming apparatus. There is a possibility that the uppermost sheet climbs over the side wall, and drops into a portion in the inside of the image forming apparatus and between the sheet cassette and the drive unit. Here, the portion in the inside of the image forming apparatus and between the sheet cassette and the drive unit is defined as a rear side space of the sheet cassette. Even if the uppermost sheet does not contact the paper feed roller, there is a possibility that the sheet drops into the rear side space of the sheet cassette by the shock when the sheet cassette is inserted into the inside of the image forming apparatus. This phenomenon is liable to occur when a maximum number of sheets are stacked on the sheet cassette.
When the sheet cassette is inserted into the inside of the image forming apparatus in the state where the sheet drops in the rear side space of the image forming apparatus, there is a possibility that various defects occur in the image forming apparatus. The sheet dropped in the rear side space of the sheet cassette cuts off the coupling between the coupling member and the drive unit, or damages these parts.
Although the defects as stated above exist, the user can not recognize that the sheet is significantly shifted from a normal set position in the sheet cassette, and further, the user can not recognize even that the sheet drops in the rear side space of the sheet cassette.
In general, according to one embodiment, an image forming apparatus includes a cassette, a sensor and a controller. The cassette stacks a sheet. The sensor is provided at the rear end of the cassette. When the sensor detects the protrusion of the sheet from the cassette, the controller controls to notify that the sheet protrudes by using an alarm.
The scanner 30 is located at an upper part of the image forming apparatus 1. The scanner 30 captures image information, which is an object of image formation in the image forming part 10, from a document as image data. The control panel 40 is located at an upper part of the image forming apparatus 1. The control panel 40 has an input function to input the start of image formation in the image forming part 10 and the start of reading of image information of a document by the scanner 30. The control panel 40 has a display function to display various messages to the user. The paper discharge tray 50 is located at the side of the image forming apparatus 1. The paper discharge tray 50 stacks the sheet subjected to the image formation by the image forming part 10.
The sheet cassette 201 includes a housing 2011, a front-side side wall 2012F, a rear-side side wall 2012R, an end wall 2013, a tray 2014 and a sensor 2015. The housing 2011 is box-shaped, and sheets are stacked and received in the inside thereof. In the housing 2011, the sheet bundle is stacked so that the X direction coincides with the width direction of the sheet, and the Y direction coincides with the longitudinal direction of the sheet. The front-side side wall 2012F contacts the side surface, at one end side (front side), of the sheet bundle stacked on the sheet cassette 201. The front-side side wall 2012F moves back and forth in the X direction, and regulates the position of the sheet in the width direction. Similarly, the rear-side side wall 2012R contacts the side surface, at the other end (rear side), of the sheet bundle stacked on the sheet cassette 201. The rear-side side wall 2012R moves back and forth in the X direction, and regulates the position of the sheet in the width direction.
The end wall 2013 contacts the surface, at the rear end side, of the sheet bundle in the Y direction. The end wall 2013 moves back and forth in the Y direction, and regulates the position of the sheet in the longitudinal direction. The tray 2014 contacts the lowermost surface of the sheet bundle stacked on the housing 2011.
Incidentally, in this embodiment, sheet displacement means that the sheet climbs over the rear side wall surface of the sheet cassette 201 and is displaced to a position where the sheet contacts the sensor 2015. Sheet remaining means that the sheet subjected to the sheet displacement drops in the rear side space of the sheet cassette 201, and remains in the inside of the image forming apparatus 1.
The sensor 2015 is positioned in the vicinity of the wall surface of the sheet cassette 201 at the rear side. The sensor 2015 protrudes in the vertical direction from the housing 2011. The sensor 2015 is a rod-shaped actuator. The sensor 2015 detects a change of pressure due to the contact of something with a portion protruding in the vertical direction from the housing 2011. While the sensor 2015 detects that some pressure is applied, the sensor is placed in the ON state and outputs a signal. That is, the sensor 2015 can detect the sheet displacement. Specifically, the sensor 2015 detects the sheet which climbs over the rear-side side wall 2012R in the X direction, and further climbs over the rear side wall surface of the sheet cassette 201 (protruding from the housing 2011). While nothing contacts the portion protruding from the housing 2011 in the vertical direction, that is, no pressure is applied, the sensor 2015 is placed in the OFF state and does not output a signal. When the sheet cassette 201 is pulled out from the image forming apparatus 1, the sensor 2015 pulls out the sheet subjected to the sheet displacement, together with the sheet cassette 201, from the inside of the image forming apparatus 1. The sensor 2015 functions also as a stopper to prevent the sheet from remaining in the image forming apparatus 1.
The bottom of the sheet cassette 201 also has a groove similar to the groove 2021 in the X direction so that it does not contact the sensor of the sheet cassette 203 located below the sheet cassette 201. The bottom of the sheet cassette 203 also has a groove similar to the groove 2021 in the X direction so that it does not contact the sensor of the sheet cassette 204 located below the sheet cassette 203. The bottom of the image forming part 10 located above the sheet cassette 202 also has a groove similar to the groove 2021 in the X direction so that it does not contact the sensor of the sheet cassette 202. The bottom of the sheet cassette 204 is not required to have a groove since a member to be pulled out from the image forming apparatus 1 and having a sensor does not exist below the sheet cassette 204. That is, the bottoms of at least the sheet cassettes 201, 202 and 203 and the image forming part 10 have the grooves. Incidentally, when the sheet cassette 204 can be received at an arbitrary position of the sheet conveyance device 20, for example, at the position of one of the sheet cassettes 201, 202 and 203 shown in
The bottom of the sheet cassette 201 also has a cover member similar to the cover member 2022 at the front side so that it faces the sensor of the sheet cassette 203 located below the sheet cassette 201. The bottom of the sheet cassette 203 also has a cover member similar to the cover member 2022 at the front side so that it faces the sensor of the sheet cassette 204 located below the sheet cassette 203. The bottom of the image forming part 10 located above the sheet cassette 202 also has a cover member similar to the cover member 2022 at the front side so that it faces the sensor of the sheet cassette 202. The bottom of the sheet cassette 204 is not required to have a cover member at the front side since there is no member which is located below the sheet cassette 204, is pulled out from the image forming apparatus 1 and has a sensor. That is, the bottoms of at least the sheet cassettes 201, 202 and 203 and the image forming part 10 have the cover members at the front side. Incidentally, when the sheet cassette 204 can be received at an arbitrary position of the sheet conveyance device 20, for example, at a position of one of the sheet cassettes 201, 202 and 203 shown in
Next, a description will be made on various modes concerning the structure of the sensor 2015 and the connection between the sensor 2015 and the housing 2011. As shown in
Further, as shown in
Further, the sensor 2015 has a notch 2015a. The notch 2015a is located in the vicinity of the tip of the surface of the sensor 2015, which contacts a sheet. The notch 2015a is dented in the X direction from the surface of the sensor 2015, which contacts the sheet, in the state where the sensor 2015 protrudes in the vertical direction. The notch 2015a is provided in the Y direction on the surface of the sensor 2015, which contacts the sheet. The notch 2015a catches the sheet before the sheet climbs over the sensor 2015 in the X direction. Incidentally, the notch 2015a has only to be capable of catching the sheet, and its shape is not limited. A recess or a concave part may be adopted. Even if the sheet cassette 201 is pulled out from the image forming apparatus 1 in the state where the sheet displacement occurs, the sheet subjected to the sheet displacement, together with the sheet cassette 201, is pulled out from the inside of the image forming apparatus 1 in the state where it is caught by the notch 2015a.
The surface of the sensor 2015, which contacts the sheet, is orthogonal to the X direction in the state where the sensor protrudes in the vertical direction. As the surface of the sensor 2015, which contacts the sheet, becomes large, the function as a stopper to the sheet becomes effective. Although
In this embodiment, the CPU 901 always monitors whether the signal from the sensor 2015 is on or off. When detecting the signal from the sensor 2015 (in other words, the sensor 2015 detects the contact of a sheet), the CPU 901 controls the control panel 40 to display an attention message indicating that there is a possibility that the sheet displacement occurs. The control panel 40 functions as an alarm of the attention message. Incidentally, the CPU 901 may control so that the attention message or a warning sound is outputted as sound from the control panel 40. The CPU 901 may control to turn on a lamp of the control panel 40. The CPU 901 may control the control panel 40 so that the display of the attention message, the sound output, and the turning-on of the lamp are executed in an arbitrary combination simultaneously or in sequence. Incidentally, after the sensor 2015 is placed in the off state and the open and close sensor detects that the sheet cassette 201 is completely inserted in the image forming apparatus 1, the CPU 901 controls to resume the conveyance of a sheet by the paper feed roller 21.
According to this embodiment, when the sheet cassette 201 is pulled out from the image forming apparatus 1, the sheet displacement can be detected, and the sheet remaining can be prevented. The user confirms the attention message displayed on the control panel 40, and can early recognize the possibility of the occurrence of the sheet remaining. As a result, the user removes the sheet subjected to the sheet displacement, and can prevent a defect from occurring in the image forming apparatus 1.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
This application is based upon and claims the benefit of priority from Provisional Application No. 61/310,169, filed on Mar. 3, 2010, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61310169 | Mar 2010 | US |
