JPH11310342A - Sheet feeder and image forming device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge electricity charged to sheets before the sheets are separated in a sheet feeder. SOLUTION: A sheet feeder 20 is provided with a sheet stacking means 22 detached from a main body 21 and capable of stacking sheets, a feeding means 23 for feeding sheets S on the sheet stacking means, and grounding means 41, 24 and 56 for grounding the sheets on the stacking means 22. Each grounding means is provided with a contact 41 provided on the sheet stacking means so as to be brought into contact with the sheets, and a conductive material 24 provided in the main body 21 so as to be grounded and brought into contact with the contact 41 when the sheet stacking means is fixed to the main body 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet feeding apparatus for feeding a sheet, and an image forming apparatus including the apparatus, such as a printer, a copying machine, and a facsimile.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional sheet feeding apparatus is detachable from a main body 2 of a sheet feeding apparatus 1.
A cassette-like sheet stacking means 3 in which a plurality of sheets S are stored; an elevating means 5 for elevating and lowering an elevating table 4 in the sheet stacking means 3 mounted on the main body 2; Feeding means 6 for separating and feeding the sheets stacked on the lifting table 4. Sheet feeding device 1
Is connected to an inkjet printer 10 which is an example of an image forming apparatus.

When the sheet stacking means 3 is mounted on the main body 2, the elevating means 5 raises the elevating table 4 so that the sheet S approaches the feeding means 6. The feeding unit 6 feeds the sheet S to the separation roller pair 7 based on a print start signal from the inkjet printer 10. When the sheets overlap, the separation roller pair 7 separates and feeds only one sheet to the inkjet printer 10.

[0004] However, the sheet S may be charged with static electricity, and the ink jet printer 10 may not be able to form a clear image on the sheet. Also,
The sheets fed to the inkjet printer 10 may be mutually sucked and partially overlap. For this reason, the image forming means 11 of the ink jet printer 10
Before or after, or in the image forming means 11, a not-shown charge removing means for removing static electricity is provided.

[0005]

However, the sheet remains charged until it is sent to the static elimination means. For this reason, the conventional sheet feeding apparatus has a problem that the sheet cannot be reliably separated and fed by the separation roller pair.

Further, if the ink jet printer is provided with such a sheet feeding device, a plurality of sheets may be sent in a pile, and an accurate image cannot be formed on the sheets.

(Purpose) The present invention provides a sheet feeding apparatus for removing electricity from a sheet before separating the sheet, and an image forming apparatus capable of forming an accurate image on the sheet. The purpose is to:

[0008]

The above object is achieved by the following sheet feeding apparatus.

A sheet stacking means which is detachable from the main body and which can stack sheets, a feeding means for feeding the sheet on the sheet stacking means, and a ground for grounding the sheet on the sheet stacking means. Means, wherein said ground means is provided on said sheet stacking means and is in contact with said sheet, and provided on said main body and grounded,
And a conductor with which the contact contacts when the sheet stacking means is mounted on the main body.

Further, the contact is fed next by the feeding means and comes into contact with the sheet.

Further, the sheet stacking means has an elevating platform for loading and elevating the sheet, and the contact is in contact with the sheet ascending and descending by the elevating platform.

The above problem is solved by the following image forming apparatus.

The image forming apparatus includes any one of the above-described sheet feeding devices, and image forming means for forming an image on a sheet fed by the sheet feeding device.

(Operation) The contact is grounded when it comes into contact with a conductor when the sheet stacking means is mounted on the main body of the sheet feeding apparatus.

The sheet comes into contact with the contact when the sheet is stacked on the sheet stacking means, or when the sheet stacking means is mounted on the main body of the sheet feeding device and moved up and down by the elevating table. As a result, the charged electricity of the sheet is released, and the sheet feeding device surely separates and feeds the sheets one by one.

The image forming apparatus performs image processing on the sheets reliably sent one by one from the sheet feeding apparatus.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an ink jet printer as an example of an image forming apparatus will be described.

The ink jet printer 10 includes an ink jet head (image forming means) 11 for discharging fine ink for forming an image, and an ink jet printer 10
And a transport belt 13 that circulates and rotates a drive shaft 12 to transport the sheet. The sheet is conveyed by the conveyance belt 13 from right to left in FIG. While the sheet is being conveyed, an image is formed on the surface of the sheet by ink ejected from the inkjet head 11 that reciprocates in a direction orthogonal to the conveying direction.

The configuration of the sheet feeding device will be described.

The sheet feeding device 20 mainly includes a housing 21 as a main body, and a cassette holder 22 as sheet stacking means which is attached to and detached from the housing 21.

The housing 21 is provided with the ink jet printer 10.
The upper portion is provided with a feed roller 23 for feeding and separating the sheet S to and from the inkjet printer 10, and a pair of separation rollers 29, 29. A leaf spring 24, which is a grounded conductor, is provided at a vertically intermediate portion of the housing 21.

The side plates 25 and 26 (see FIGS. 3 and 4) of the housing 21 are provided with lifting arms 27 and 27 as lifting means for raising and lowering synchronously. Both lifting arms 2
At the upper end of the tip 7, there are provided round bar-shaped receiving projections 28, 28 for receiving an elevator 34 described later.

As shown in FIG. 5, the cassette holder 22
Has a casing 30 and a lifting table 34 on which sheets can be loaded and lowered. The casing 30 includes a side plate 31,
31; a rear plate 32; a front plate 33 which can be opened and closed;
And a bottom plate 43 for receiving the bottom plate 4. The front plate 33 is
The convex portion 35 and the concave portion 36 that fit each other are held in a closed state by the side plate 31. A pair of protrusions 37 and 38 projecting outward from the side plate 31 are provided on both sides of the lift table 34. The elevating table 34 is guided by the projections 37 and 38 and a pair of slits 39 and 40 formed on the side plate 31 and opened at the lower end to move up and down. At the lower ends of the projections 37, 38, recesses 37a, 38a to be fitted with the receiving projections 28 are formed.

On the projection 37 closer to the rear plate 32, a claw 37b abutting on the receiving projection 28 is provided so as to project downward.
The rear plate 32 is provided with a contact 41 having elasticity that comes into contact with a sheet in the cassette holder 22 through the through-hole 42.

The size of the cassette holder 22 differs depending on the size of sheets to be stacked and stored. For this reason, when attached to the housing 21 of the sheet feeding device 20,
The rear plate 32 shown in FIG. 1 includes a sheet holder, as shown in FIG.
One pair of identification protruding pieces 50 and 51 is provided vertically. The identification protrusions 50 and 51 are provided on the sensor 5 disposed on the housing 21 side.
2, 53 are in contact with each other. The identification protrusions 50 and 51 are inserted into the support holes 54 and 55 of the housing 21 and also serve to support the cassette holder 22 on the housing 21.

The operation of the sheet feeding device will be described.

The sheets are stacked on a lift 34 of the cassette holder 22 with the front plate 33 opened. The elevating table 34 on which the sheets are loaded is received by the bottom plate 43 until the cassette holder 22 is mounted on the housing 21 of the sheet feeding device 20.

The cassette holder 22 includes a casing 30
Is supported by the housing 21, and the lift 34 is
7 is mounted on the housing 21 by being placed on the housing 7.

The casing 30 is supported by the housing 21 by inserting the identification projections 50, 51 into the support holes 54, 55. In addition, the elevating table 34 puts the projections 37 and 38 on the receiving projections 28 on the elevating arm 27 waiting at the lowest position, and fits the recesses 37a and 38a of the projections 37 and 38 into the round bar-shaped receiving projections 28. By doing so, it is positioned and supported on the lifting arm 27. At this time, the elevator 34 is guided and positioned by the pawl 37b.

When the casing 30 is mounted on the housing 21, the contact 41 comes into contact with the leaf spring 24. Further, when the identification protruding pieces 50 and 51 are inserted into the support holes 54 and 55, they are detected by the sensors 52 and 53, and the sensors 52 and 53 determine which size of the sheet holder 22 is mounted on the housing. Is detected. The size signal is sent to the inkjet printer 10.

Thereafter, the lifting arm 27 is raised inside the casing 30 by a driving means (not shown). As the lifting arm 27 moves up, the sheet S also moves up. The sheet S comes into contact with the contacts 41 during the ascent. The static electricity charged on the sheet S is transmitted to the contact 41 and the leaf spring 2.
4 and the ground cord 56.

The elevating table 34 is still raised, and automatically stops when the uppermost sheet comes into contact with the feed roller 23. The feed roller 23 is started based on a lift stop signal of the lift 34 and a print start signal from the inkjet printer 10, and separates the sheet into a pair of separation rollers 29.
Send to At this time, since the static electricity of the sheet has been removed, the sheet hardly overlaps and is sent to the separation roller pair 29. Even if a plurality of sheets are stacked and sent out from the casing 30, the sheet S is
The sheet is separated by the separation roller pair 29 and sent to the ink jet printer 10 by only one sheet.

When a certain number of sheets S are fed into the ink jet printer 10, the elevator 34 is raised again, and the uppermost sheet is raised to such a height that it can be easily fed into the ink jet printer 10.
At this time, as the lift 34 rises, a new sheet comes into contact with the contactor 41 and the static electricity on the sheet is removed.

The contact may be provided on the upper part of the casing 30 as shown in FIGS. The contact 60 in this case is made of a conductive plate 61 provided on the casing 30.
And is in surface contact with the uppermost sheet surface. Therefore, the contact 60 can reliably remove static electricity. Moreover, since the contact 60 comes into contact with the sheet immediately before being discharged from the cassette holder 22, static electricity can be removed at the last stage of discharging from the sheet supply device.

The leaf spring 41 is connected to the earth cord 56, but when the housing 21 is formed of a conductive material,
For example, when a sheet metal is formed by bending, an earth cord becomes unnecessary.

The operation of the ink jet printer will be described.

In FIG. 1, an ink jet printer 1
0 sets the reciprocating width of the inkjet head 11 based on the sheet size signal from the sheet feeding device 20, and conveys the sheet sent from the sheet feeding device 20 by the transport belt 13, 11
Is reciprocated to eject ink and form an image on a sheet. Since the inkjet printer 10 reliably sends sheets one by one from the sheet feeding device 20,
Images can be reliably formed one by one on a sheet.

[0038]

According to the sheet feeding apparatus of the present invention, a grounding means is provided for contacting the sheet on the replaceable sheet stacking means, and the charging of the sheet is performed through the grounding means before the sheet is separated and fed. Since the sheets are discharged, the sheets can be reliably separated and fed one by one.

According to the image forming apparatus of the present invention, since the sheet feeding device capable of feeding the sheets one by one is provided, the image can be formed on the sheets one by one.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view of a sheet feeding apparatus according to an embodiment of the present invention and an ink jet printer including the sheet feeding apparatus.

FIG. 2 is a diagram in which an elevator of the sheet feeding apparatus in FIG. 1 is lifted.

FIG. 3 is a diagram when the cassette holder is placed on the lifting arm, as viewed from the inkjet printer side.

FIG. 4 is a diagram in which a lifting platform is raised.

FIG. 5 is a perspective view of the cassette holder of FIG. 1;

FIG. 6 is a schematic front sectional view of a sheet feeding device according to another embodiment and an ink jet printer having the device.

FIG. 7 is a perspective view of the cassette holder of FIG. 6;

FIG. 8 is a schematic front sectional view of a conventional sheet feeding device and an ink jet printer having the device.

[Explanation of symbols]

 S Sheet 10 Inkjet Printer (Image Forming Device) 11 Inkjet Head (Image Forming Means) 13 Conveying Belt (Image Forming Means) 20 Sheet Feeding Device 21 Housing (Main Body) 22 Cassette Holder (Sheet Loading Means) 23 Feeding Roller ( Feeding means) 24 Leaf spring (conductor, grounding means) 41 Contact (grounding means) 56 Earth cord (grounding means) 60 Contactor (grounding means) 61 Conductive plate (grounding means)

Claims (4)

[Claims] 1. A sheet stacking means detachable from a main body and capable of stacking sheets, a feeding means for feeding the sheets on the sheet stacking means, and a sheet on the sheet stacking means grounded A grounding means, wherein the grounding means is provided on the sheet stacking means and is in contact with the sheet, and the grounding means is provided on the main body and the sheet stacking means is mounted on the main body. A sheet feeding device, comprising: a conductor that contacts the contactor. 2. The sheet feeding apparatus according to claim 1, wherein the sheet stacking means has a lifting platform for loading and lifting the sheets, and the contact contacts a sheet raised and lowered by the lifting platform. . 3. The sheet feeding device according to claim 1, wherein the contact is next fed by the feeding means and comes into contact with a sheet. 4. An image, comprising: the sheet feeding device according to claim 1, 2 or 3, and image forming means for forming an image on a sheet fed by the sheet feeding device. Forming equipment.