JP2002308466A - Feeder and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of an apparatus by reducing the size of a paper feeder, and to improve convenience of the paper feeder. SOLUTION: A paper feed tray 40 for feeding a sheet P has a detecting roller 51 for detecting passing of the last loaded sheet and a lever 53 for energizing the sheet P to the detecting roller 51. The lever 53 is rotated interlocking with the operation of storing the paper feed tray 40 to store the sheet in the paper feed tray 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feeding device such as a feeding tray for feeding sheets and an image forming apparatus provided with the feeding device.

[0002]

2. Description of the Related Art A manual feeder such as a manual feed tray of a conventional image forming apparatus is provided with a sensor for detecting the presence or absence of a sheet, and detects the presence or absence of a sheet before image formation or the presence or absence of a sheet during image formation. I have.

However, particularly in an image forming apparatus such as a full-color printer or a copying machine, a toner image formed on a photosensitive drum is transferred to an intermediate transfer body, and is transferred onto a sheet conveyed from a manual feeder. In an image forming apparatus in which a secondary transfer roller transfers a toner image on an intermediate transfer member, the following problem occurs.

[0004] With the sheet presence / absence detection sensor provided in the conventional image forming apparatus, when the absence of a sheet is detected, the toner image has already been transferred from the photosensitive drum onto the intermediate transfer body. Troubles such as soiling the body with toner occurred. In view of this, with respect to the above-described image forming apparatus, by rotating the rollers to start the movement of the last sheet (last sheet) in the manual feeder,
Last sheet detection means for detecting the last sheet is provided to prevent contamination by toner.

In the last sheet detecting means, a lever is provided in a direction for urging the sheet against the roller, and the sheet is surely brought into contact with the roller so that the roller is accurately rotated so that the detection of the last sheet is performed reliably. It has a simple configuration.

[0006]

However, if a lever is provided in a direction in which the roller is securely brought into contact with the sheet, the roller itself is provided in the manual feeding device, so that space is required for disposing the lever. And the device becomes larger. In addition, there was a problem that the lever was in the way when the seat was set.

An object of the present invention is to reduce the size of the feeding device by reducing the size of the device. Another object is to improve the usability of the feeding device.

[0008]

In order to achieve the above object, a typical configuration of the present invention is a rotating body for detecting the passage of the last stacked sheet, and a rotating body for urging the sheet against the rotating body. A feeding device for feeding a sheet, wherein the urging device rotates and is housed in the feeding device in conjunction with an operation of housing the feeding device. And

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described with reference to the drawings. 1 is a schematic diagram of the image forming apparatus, FIG. 2 is a diagram illustrating a state where sheets are stacked on a feed tray, and FIG. 3 is a diagram illustrating a state where sheets are conveyed on the feed tray. FIG. 4 is a diagram illustrating a state where the feeding tray is stored in the image forming apparatus.

As shown in FIG. 1, a four-drum full-color color printer is exemplified as the image forming apparatus 1. In the image forming apparatus 1, a photosensitive drum 21 (21Y, 21M, 21C, 21Bk) of each color as an image carrier is provided for each image forming station provided with yellow, magenta, cyan, and black developers (toners). Have been.

Each photosensitive drum 21 (21Y, 21M, 21C, 21C)
The surface of Bk) is a laser scanner device 22 corresponding to each color.
(22Y, 22M, 22C, 22Bk) to form an electrostatic latent image on the photosensitive drum 21 by being exposed to laser light emitted from the photosensitive drum 21. A toner image is formed on the electrostatic latent image by toner of each color, and thereafter, the toner image on the photosensitive drum 21 is
The image is transferred to the intermediate transfer belt 30.

Sheets P are stacked on the feeding cassette 10 and a feeding tray 40 as a feeding device. At the time of cassette feeding, the sheet P is fed from a feeding cassette 10 by a feeding roller 11, and the sheet P is conveyed to a secondary transfer roller 16 through a feed retard roller 12 and a conveying roller pair 13. When the tray is fed, M
The sheet P is fed by the P feed roller 14, the sheet P is directly abutted against the registration roller pair 15, and after forming the loop, the registration roller pair 15 is rotated and conveyed to the secondary transfer roller 16.

The toner image formed on the intermediate transfer belt 30 is transferred to the sheet P conveyed between the intermediate transfer belt 30 and the secondary transfer roller 16, and is transferred by the fixing device 17 downstream of the conveyance path. The applied toner image is fixed on the sheet P. Thereafter, the sheet P is discharged to the discharge tray 20 by the discharge rollers 18 and 19. Next, the feeding tray 40 will be specifically described.

As shown in FIG. 2, the feed tray 40 has last sheet detecting means 50 for detecting the last sheet (last sheet) loaded. Last sheet detection means 50
Are a detection roller 51 as a rotating body that rotates when the sheet P abuts, a photo interrupter 52 that detects the rotation of the detection roller 51, and a biasing unit that abuts the sheet P in the direction of the detection roller 51. It has a lever 53, a lever holder 54 for holding the lever 53, butting springs 55 and 56, and a presence / absence detection sensor 59 for detecting the presence / absence of the sheet P upstream of the MP feeding roller 14 in the conveyance direction.

Here, the lever 53 is formed integrally with the rotating shaft 53a, and is urged via a sheet P to a detection roller 51 provided on the feeding tray 40 by an abutting spring 55. The lever holder 54 has a bearing for the rotating shaft 53a,
53 is rotatable around this bearing. Further, the lever holder 54 itself also has a rotating shaft 54a of an integral structure, is rotatable around a bearing (not shown) protruding from the feeding tray frame 57, and abutment provided on the feeding tray frame 57. Department
It is urged by abutment spring 56 to 58.

Then, when the image forming apparatus 1 receives the print signal, the required number of sheets P
Registration roller pair 15 by P feed roller 14 (see FIG. 1)
Is fed in the direction of arrow A toward. When the fed sheet P is the last sheet, the lever 53
Is urged to the detection roller 51, the detection roller 51 rotates in response to the conveyance of the sheet P, and the slit provided in the detection roller 51 causes the photo interrupter 52 to rotate more than a predetermined number of times within a predetermined time. When turned ON / OFF, the sheet P is determined to be the last sheet, and after outputting the last sheet, the image forming process is temporarily stopped.

As shown in FIG. 3, when the conveyance of the sheet P determined to be the last sheet further proceeds and passes through the presence / absence detection sensor 59, the flag provided in the presence / absence detection sensor 59 shuts off the photo interrupter 52, The presence or absence of the sheet P on the feed tray 40 is recognized again. When the sheet P is set in this state, the presence / absence detection sensor 59 rotates to determine that the sheet P is loaded on the feed tray 40, and the image forming process is restarted.

When no sheets P are stacked on the feed tray 40, the feed tray 40 can be stored. Next, a configuration for storing the feed tray 40 will be described. A tray 41 and an auxiliary tray 42 are provided on the feed tray 40 for stacking long sheets P in the transport direction. The tray 41 has a shaft 41a that can extend and contract along the guide 60, and the auxiliary tray 42 is foldable with respect to the tray 41 about a rotation axis (not shown).

When storing the feed tray 40, first, the auxiliary tray 42 for stacking the long sheets P on the feed tray 40 in the conveying direction is rotated to the tray 41. Auxiliary tray 42
Is slid along the guide 60 of the tray cover 43.

As shown in FIG. 4, when the tray cover 43 is pushed in the transport direction, the feed tray 40 pushes the lever 53 and the lever holder 54. The feed tray 40 is closed.

As described above, the detection tray 51 for detecting the passage of the last sheet stacked and the lever 53 for urging the sheet P to the detection roller 51, and the feeding tray 40 for feeding the sheet P are provided. In, since the lever 53 is rotated and stored in the feed tray 40 in conjunction with the operation of storing the feed tray 40,
The lever 53 need not always be extended, and the size of the image forming apparatus can be reduced by reducing the size of the feed tray 40. Further, the usability of the feeding tray 40 can be improved.

(Second Embodiment) A second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a diagram illustrating a state in which sheets are stacked on a feeding tray, and FIG. 6 is an explanatory diagram of a configuration of a lever. In the description of the second embodiment, the first
The same components as those of the embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 5, last sheet detecting means
70 is a detection roller 51, a photo interrupter 52, a presence / absence detection sensor 71, a lever 72, a presence / absence detection sensor spring 73,
And a lever spring 74. The presence / absence detection sensor 71 is rotatable about a rotation shaft 71 a that is integrally formed, and is urged by a presence / absence detection sensor spring 73 in a direction opposite to the transport direction. Here, as shown in FIG. 6, the lever 72 has a bearing portion, and is rotatably pressed by an abutting portion 71b provided on the presence / absence detection sensor 71.

In FIG. 5, the sheet P is placed on the feeding tray 40.
Is loaded, the end of the sheet P rotates the presence / absence detection sensor 71 (from the state of the broken line to the state of the solid line), and the lever 72 that has been rotated together with the presence / absence detection sensor 71 contacts the sheet P. At this time, the lever 72 is urged by the lever spring 74 to the detection roller 51 provided on the feed tray 40 via the sheet P.

Here, when the sheets P are stacked, since the rotation of the presence / absence detection sensor 71 and the lever 72 are linked, the lever 72 is separated from the feed tray 40, and a space is secured on the feed tray 40. Therefore, the sheet P can be set easily.

As described above, the lever 72 is connected to the feed tray 40
The sheet P is rotated in conjunction with the operation of storing the sheet P, and is not only stored in the feeding tray 40, but also rotated in conjunction with the operation of inserting the sheet P into the feeding tray 40. Since it can be easily performed, the size of the image forming apparatus can be reduced by downsizing the feed tray 40, and the usability of the feed tray 40 can be further improved.

(Other Embodiments) In the above-described embodiment, a four-color color printer has been exemplified as an image forming apparatus. However, the present invention is not limited to this, and is also applicable to image forming apparatuses such as facsimile machines and copiers. May be applied.

Further, in the above-described embodiment, the feeding device is formed integrally with the image forming apparatus as the feeding tray 40. However, the present invention is not limited to this. Is also good.

[0029]

As described above, according to the present invention, in the feeding device for feeding a sheet, the urging means is rotated in conjunction with the operation of storing the feeding device, and the urging means is rotated into the feeding device. Since the sheet is stored, the size of the apparatus can be reduced by reducing the size of the feeding apparatus. Further, the usability of the feeding device can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus.

FIG. 2 is a diagram illustrating a state in which sheets are stacked on a feeding tray.

FIG. 3 is a diagram illustrating a state where a sheet is conveyed in a feeding tray.

FIG. 4 is a diagram illustrating a state in which the feeding tray is stored in the image forming apparatus.

FIG. 5 is a diagram illustrating a state where sheets are stacked on a feeding tray.

FIG. 6 is an explanatory diagram of a configuration of a lever.

[Explanation of symbols]

 P: Sheet 1: Image forming apparatus 10: Feeding cassette 11: Feeding roller 12: Feed retard roller 13: Conveying roller pair 14: MP feeding roller 15: Registration roller pair 16: Secondary transfer roller 17: Fixing unit 18 ... discharge roller 19 ... discharge roller 20 ... discharge tray 21 ... photosensitive drum 30 ... intermediate transfer belt 40 ... feed tray 41 ... tray 41a ... shaft 42 ... auxiliary tray 43 ... tray cover 50 ... last sheet detecting means 51 ... detection roller 52… Photo interrupter 53… Lever 53a… Rotating axis 54… Lever holder 54a… Rotating axis 55… Abut spring 56… Abut spring 57… Feed tray frame 58… Abut section 59… Presence detection sensor 60… Guide 70… Last sheet detecting means 71… Presence detection sensor 71a… Rotating shaft 71b… Abutting part 72… Lever 73… Presence detection sensor spring 74… Lever spring

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Claims (3)

[Claims] 1. A feeding device for feeding a sheet, comprising: a rotating body for detecting the passage of the last stacked sheet; and a biasing means for biasing the sheet to the rotating body. A feeding device, wherein the urging means is rotated and stored in the feeding device in conjunction with an operation of storing the feeding device. 2. The feeding device according to claim 1, wherein the urging unit rotates in conjunction with an operation of inserting a sheet into the feeding device. 3. An image forming apparatus comprising: an image carrier; and a feeding device, wherein the toner image formed on the image carrier is transferred to a sheet fed from the feeding device. An image forming apparatus, wherein the apparatus is the feeding apparatus according to claim 1.