JP3333343B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder used in an image forming apparatus utilizing an electrophotographic system.

[0002]

2. Description of the Related Art As shown in a perspective view schematically in FIG. 9, this type of conventional paper feeder is constituted by a paper feed cassette detachably mountable to an image forming apparatus main body. In FIG. 9, 1
Denotes a device main body of the image forming apparatus, 2 denotes a sheet feeding cassette for storing a plurality of sheets, 3 denotes a sheet feeding roller for feeding sheets one by one from the sheet feeding cassette 2 to the apparatus main body 1, 4a denotes a pressing roller, 4b Is a pressure plate. Also, K is the direction of attachment / detachment of the sheet cassette 2, L is the sheet width direction, Q is the sheet cassette width, and R is the sheet cassette opening width.

The width R of the sheet cassette in the sheet cassette mounting opening provided in the apparatus main body 1 is slightly larger than the sheet cassette width Q. The position of the paper feed cassette 2 was determined by the fitting dimensions. However, since the size of the paper feed cassette 2 is larger than that of the paper that enters the paper feed cassette 2, the width Q of the paper feed cassette that uses the large-size paper for A3 is 300 mm or more. In the paper width direction L becomes larger. Therefore, the device body 1
There is a problem that the position of the paper feed cassette 2 deviates from the position of the writing reference, and the position of the paper and the printed character are shifted when printing is performed.

In order to solve the above-mentioned problem, Japanese Patent Laid-Open No.
As described in Japanese Patent No. 5837, a sheet feeding cassette and a manual feed tray are pressed against a positioning portion of a sheet printing position by pressing means such as a spring. When the paper cassette 2 shown in FIG. 9 is mounted on the apparatus main body 1 in order to prevent misalignment of printing, the paper cassette 2 is
Pressing means is provided for pressing one side, which is a reference position in the sheet width direction L, by the pressing plate 4b provided with a.

[0005]

However, the paper cassette having such a configuration has a large fitting size because it has a pressing means for pressing the paper cassette in order to prevent the printing position of the paper from shifting. It becomes bigger. Further, since parts such as a pressing roller and a pressing plate are required as the pressing means, there has been a problem that the number of parts and the number of assembling steps are increased and the cost is increased.

The present invention solves the above-mentioned problem of the prior art, in which a first concave portion, a first convex portion, a second convex portion, and a second concave portion are provided in an image forming apparatus main body and a paper feed cassette. The positioning of the sheet cassette is performed by providing the second convex portion and the second
It is an object of the present invention to provide a paper feeder in which the writing reference position for printing on paper is not deviated and the detachment operation can be carried out smoothly without reducing the play due to the fitting tolerance due to the recess.

[0007]

In order to achieve this object, the present invention provides a paper feed cassette for storing a plurality of sheets.
Feeding paper detachably installed at the bottom of the main body of the image forming apparatus
In the apparatus , a first concave portion provided in guide means of the sheet cassette at both lower ends of the image forming apparatus main body for positioning the sheet cassette in a mounting / removing direction, and bottom portions at both ends of the sheet cassette. The side wall of the paper cassette
Paper of independent and first convex portions to be fitted with the first recess provided on an outer surface substantially flush with said first recess and the first protrusion, to Cartesian and detachable direction An opening for mounting a sheet cassette of the image forming apparatus main body for performing positioning in a width direction.
A second projection provided on the upper side of a front upper portion of the paper feed cassette, the inner surface of the paper feeding cassette side walls
Furthermore, a second concave portion provided inside the side wall and fitted to the second convex portion is provided.

A second convex portion and a second concave portion for positioning in the sheet width direction are formed on a same straight line parallel to a handle provided for attaching and detaching the sheet cassette and the attaching and detaching direction of the sheet cassette. Is characterized by being located at

Further, the second convex portion and the second concave portion for positioning in the sheet width direction are located on a straight line parallel to the attaching / detaching direction passing through the center of gravity of the sheet cassette.

The rear end of the second convex portion facing the paper feed roller is flush with the guide surface of the conveyance guide member of the image forming apparatus main body and protrudes downward from the conveyance guide member. It is configured as follows.

[0011]

According to the above arrangement, the first concave portion, the first convex portion, the second convex portion, and the second concave portion are provided in the image forming apparatus main body and the sheet feeding cassette, and the first concave portion and the first concave portion are provided. The convex portion, the second convex portion, and the second concave portion are fitted to each other to determine a writing reference position in the paper cassette attaching / detaching direction and the paper width direction.

Further, the second convex portion, the concave portion, and the handle portion of the sheet cassette are provided so as to be located on the same straight line parallel to the attaching / detaching direction, so that the sheet cassette can be smoothly attached / detached.

Further, the second convex portion and the concave portion are provided so as to be located on the same straight line parallel to the attaching / detaching direction passing through the center of gravity of the sheet cassette, so that the sheet cassette can be smoothly attached / detached.

The rear end of the second convex portion of the main body of the image forming apparatus opposite to the sheet feeding roller is provided on the same plane as the guide surface so as to protrude below the conveyance guide member, thereby providing the main body of the image forming apparatus. The paper does not enter the gap between the conveyance guide member and the paper feed cassette.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing the structure of an image forming apparatus using an electrophotographic method. It should be noted that in the description of the conventional example of FIG. 9 and the following drawings, components having the same function are denoted by the same reference numerals.

In FIG. 1, 1 is an apparatus main body, 1a is a cover of the apparatus main body 1, 2 is a paper feed cassette, 3 is a paper feed roller,
Reference numeral 5 denotes a photosensitive member located at a substantially central portion, 6 denotes a charging unit, 7 denotes a developing unit, 8 denotes a transfer unit, 9 denotes a cleaning unit, and 10 denotes a photosensitive member 5, a charging unit 6, a developing unit 7, and a cleaning unit 9.
, A registration roller 11 for feeding the fed paper P to the transfer means 8, a fixing means 12 for fixing the transferred image, and a discharge roller 13 for ejecting the image-recorded paper P out of the apparatus main body 1. A paper discharge roller, 14 is a stock unit on which the recorded paper P is placed, 15 is a case, 16 is an electrical unit, 17
Is a power supply unit, 18 is an optical means, 19 is a paper support member, 19a is a horizontal portion of the paper support member 19, 19b is a vertical portion of the paper support member 19, 20 is a transport path in the paper feed cassette 2, and 20a is a paper feeder. A conveyance guide member for conveying the fed sheet to the registration roller 8;
20b is a guide surface of the transport guide member 20a, 21 is a handle of the paper feed cassette, and P is a sheet.

At a substantially central portion of the apparatus main body 1, there is provided a cartridge 10 having a photoreceptor 5 and the like. A paper feed cassette 2 is disposed below the cartridge 10, and a paper P fed from a paper feed roller 3 is transported by a transport guide. The registration roller passes through the guide surface 20b of the member 20a.
The print data is sent to the transfer means 8 at a predetermined timing by 11. The paper P on which the toner image of the photoconductor 5 is recorded
The discharge roller is fixed by the fixing means 12 located above
By 13, it is discharged and placed on the stock unit 14.

The cover 1 which is a part of the case of the apparatus body 1
Below the stock portion 14 and the cover 1a provided on the upper surface of the a, a controller board and various adjustment switches and control units (not shown) mounted on the controller board in a metal case 15 are provided. The electrical unit 16 is further provided with a power supply unit 17 therebelow. And
Optical means 18 for writing an image on photoconductor 5 is a case
It is located below 15.

In the stock section 14, the discharged paper P
A paper support member 19 for supporting the leading end of the paper discharge direction is slidably provided in the paper discharge direction. The paper supporting member 19 is composed of a horizontal portion 19a and a vertical portion 1 with respect to the paper discharging direction.
9b is formed in a substantially L-shape.

An optional paper feed unit (not shown) can be added below the paper feed cassette 2, and the paper P fed from the optional paper feed unit passes through the transport path 20 in the paper feed cassette 2. As described above, the processing is performed in the same manner as the sheet P fed from the sheet cassette 2 thereafter.

FIG. 2 is a perspective view schematically showing an image forming apparatus main body according to the first embodiment of the present invention and a detachable portion of a sheet cassette. In FIG. 2, reference numeral 22 denotes a guide rail which is a guide means provided at the lower end of both ends of the apparatus main body 1, reference numeral 23 denotes a first concave portion provided on each guide rail 22, and reference numeral 24 denotes a first concave portion provided at the lower end of both ends of the sheet cassette 2. Reference numeral 25 denotes a second convex portion which is elongated and protrudes downward in the form of a rib on the side of the paper feed roller 3 of the mounting opening of the paper cassette 2 of the apparatus main body 1, and 25a denotes a second convex portion. 25b is a front end of the second convex portion on the side of the sheet cassette mounting opening, and 26 is a second convex portion provided on the front upper portion of the sheet cassette 2. The second concave portion is fitted to the portion 25.

The paper feed cassette 2 is mounted in the apparatus main body 1 while sliding on a guide rail 22 provided in the apparatus main body 1. At this time, the positioning of the paper feed cassette 2 in the attaching / detaching direction K is performed by the first concave portion 23 provided on the guide rail 22 provided at the lower end of both ends of the apparatus main body 1 and the first concave portion provided at the lower end of both ends of the paper feed cassette 2. Are determined by fitting of the convex portions 24 of. In addition, the paper cassette 2 is
Positioning in the sheet width direction L of intersection includes a second protrusion 25 which is fed sheet feeding roller 3 of the mounting opening of the cassette 2 of the apparatus main body 1 projecting downward from the side where the position of the paper feed cassette 2 It is determined by fitting the second concave portion 26 provided in the upper part of the front surface.

Here, both the second convex portion 25 and the second concave portion 26 have a width of only about 2 to 3 mm, and do not require as large a fitting tolerance as the apparatus main body 1 and the paper feed cassette 2. In other words, when the paper feed cassette 2 is mounted on the apparatus main body 1, the writing reference does not deviate from the position of the paper feed cassette 2, and as a result, the print position of the printed paper P does not deviate.

When the paper feed cassette 2 is mounted on the apparatus main body 1, the paper feed cassette 2 can be moved up and down by 2 to 3 mm, and the first projection 24 under the paper feed cassette 2 rides on the guide rail 22. Even if the sheet cassette 2 is lifted by the height of the first projection 24, the second projection 25 is smoothly fitted into the second recess 26. The second convex portion 25 of the apparatus main body 1 preferably has good dimensional accuracy because it serves as a reference for a writing position on the paper P, and a frame member for holding the cartridge 10 having the optical unit 18 and the photoreceptor 5. It is desirable that they are formed integrally with each other.

Next, FIG. 3 is a perspective view showing the relationship between the handle, the second concave portion, and the second convex portion of the image forming apparatus main body according to the second embodiment. FIG. 4 shows the state of the second convex portion and the second concave portion before (a) the mating resistance occurs during the mounting of the sheet cassette of the second embodiment and (b) when the mating resistance occurs during the mounting. It is explanatory drawing which shows the relationship of fitting resistance. In FIG. 4, S is a generating portion of a fitting resistance generated between the second concave portion and the second convex portion, F is a force pressing the handle portion 21 for mounting the sheet cassette 2, and Z is a force from the generating portion S. This is the distance to the position where the force F is applied.

Now, when the paper feed cassette 2 is mounted on the apparatus main body 1, the second convex portion 25 of the apparatus main body 1 and the second concave portion 26 of the paper feed cassette 2 are fitted as described in the first embodiment. It begins to match (see FIG. 4 (a)). At this time, when the handle 21, the second protrusion 25, and the second recess 26 of the sheet cassette 2 are not located on the same straight line parallel to the attaching / detaching direction K, the sheet cassette 2 is removed from the handle 21. The fitting force is generated between the second convex portion 25 and the second concave portion 26 by the force F applied in the mounting direction, and the paper feed cassette 2 is rotated by the rotational moment F × Z about the generating portion S. It is inclined obliquely (see FIG. 4B). In order to prevent the above-mentioned problem, in the second embodiment, the second convex portion 25, the second concave portion 26 and the handle portion of the sheet cassette 2 are provided.
Reference numeral 21 is provided on the same straight line parallel to the attaching / detaching direction K of the sheet cassette 2 (see FIG. 3). Thereby, even if the fitting resistance between the second convex portion 25 and the second concave portion 26 is large, the second convex portion 25
And the second concave portion 26 are fitted so that the sheet feeding cassette 2 does not tilt obliquely.

Next, FIG. 5 is a perspective view showing the relationship between the sheet feeding cassette, the second convex portion, and the second concave portion in the third embodiment. FIG. 6 is an explanatory view when a force is applied in the mounting direction from the handle before (a) and during (b) the mounting of the sheet cassette shown in the second embodiment. In FIG. 6, 27 is a left and right stopper for determining the position of the left and right side edges of the sheet P, 28 is a rear stopper for determining the position of the rear end of the sheet P, and M is the position of the center of gravity of the sheet cassette on which the sheet P is placed. .

When the paper feed cassette 2 is mounted on the apparatus main body 1, the second convex portion 25 of the apparatus main body 1 and the second concave portion 26 of the paper feed cassette 2 fitted with the second convex portion 25 are formed. If the handle portion 21 is not positioned on the same straight line parallel to the attaching / detaching direction K passing through the center of gravity M of the paper cassette 2 (see FIG. 6A), the paper cassette 2 and the paper cassette 2 The sheet cassette 2 is tilted due to the inertia force of the sheet P (see FIG. 6B). In order to prevent the above-described problem, in the third embodiment, the second convex portion 25 of the apparatus main body 1, the second concave portion 26 of the sheet cassette 2, and the handle 21 are attached and detached through the center of gravity M of the sheet cassette 2. It is provided on the same straight line parallel to the direction K (see FIG. 5). Thus, when the paper feed cassette 2 is mounted on the apparatus main body 1, the paper feed cassette 2 does not tilt obliquely due to the inertial force of the paper feed cassette 2 and the paper P, and the operation of attaching and detaching the paper feed cassette 2 can be performed smoothly.

The left and right stoppers 27 and the rear stopper 28 of the sheet cassette 2 can be slid freely so that the position of the sheet P placed on the sheet cassette 2 can be fixed even when the sheet size is changed. Therefore, the print position of the paper P is determined by determining the paper feed position of the paper feed cassette 2.

Next, FIG. 7 is a sectional view showing the relationship between the gap formed between the transport guide member and the paper feed cassette, the leading edge of the fed paper, and the second convex portion in the fourth embodiment. This is a gap formed between the guide member 20a and the sheet cassette 2. FIG. 8 is a cross-sectional view illustrating a state in which the leading end of the fed paper has entered the gap formed between the conveyance guide member and the paper feed cassette according to the fourth embodiment.

A gap B is required between the paper feed cassette 2 and the transport guide member 20a for the attachment / detachment operation of the paper feed cassette 2. However, there is a possibility that the leading end of the sheet P fed from the sheet feeding roller 3 enters the gap B (see FIG. 8). In order to prevent this, in the fourth embodiment, as shown in FIG. 7, a rear end portion 25a of the second convex portion 25 which fits into the second concave portion 26 of the paper feed cassette 2 on the side facing the paper feed roller 3. Are provided on the same plane as the guide surface 20b of the transport guide member 20a of the apparatus main body 1. This prevents the paper P from entering the gap B between the paper feed cassette 2 and the transport guide member 20a of the apparatus main body 1.

As described above, the first concave portion 23, the first convex portion 24, the second convex portion 25, and the second concave portion 26 are provided in the apparatus main body 1 and the sheet feeding cassette 2, and The positions of the second convex portion 25, the second concave portion 26 of the sheet cassette 2, and the handle portion 21 are on the same straight line parallel to the attaching / detaching direction K of the sheet cassette 2, and the center of gravity M of the sheet cassette 2 is by providing such a pass, the position in the sheet width direction L is determined to Cartesian to position the detachable direction K of the detachable direction K of the paper feed cassette 2, also facing the paper feed roller 3 of the second convex portion 25 By providing the rear end portion 25a on the same side as the guide surface 20b of the transport guide member 20a, the sheet P is inserted into the gap B when the sheet cassette 2 is mounted on the apparatus main body 1 and when the sheet is fed. Paper can be fed smoothly without entering.

[0033]

As described above, according to the present invention,
A first concave portion, a first convex portion, a second convex portion, and a second concave portion are provided in the image forming apparatus main body and the sheet feeding cassette, and the first concave portion and the first convex portion, and a first concave portion having a small fitting tolerance. The second projection and the second depression are fitted to each other, so that the writing reference position in the paper cassette attaching / detaching direction and the paper width direction can be determined, and there is no need for pressing means for pressing the paper cassette to the reference position. The number of points and the number of man-hours can be reduced to reduce costs.

Further, by providing the second convex portion, the second concave portion, and the handle portion of the sheet cassette so as to be located on the same straight line parallel to the attaching / detaching direction, the second convex portion and the second concave portion are provided. Even if the mating resistance is large, they are fitted without tilting obliquely, and the paper cassette can be mounted smoothly.

Further, by providing the second convex portion and the second concave portion so as to be located on the same straight line parallel to the attaching / detaching direction passing through the center of gravity of the sheet cassette, the sheet is fed by the inertia force of the sheet cassette and the sheet. The paper cassette can be mounted smoothly without tilting.

Further, by providing the rear end of the second convex portion of the image forming apparatus main body facing the paper feed roller on the same plane as the guide surface, the distance between the paper feed cassette and the conveyance guide surface of the apparatus main body can be improved. There is an effect that the leading edge of the paper fed from the paper feed roller does not enter into the gap between the paper feeders, and the paper can be fed smoothly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of an image forming apparatus using an electrophotographic method.

FIG. 2 is a perspective view schematically showing an attaching / detaching portion of an image forming apparatus main body and a sheet feeding cassette according to the first embodiment of the present invention.

FIG. 3 is a perspective view illustrating a relationship between a handle portion, a second concave portion, and a second convex portion of the image forming apparatus main body according to the second embodiment of the present invention.

FIG. 4 is a diagram illustrating a second convex portion and a second convex portion before (a) generating a mating resistance during the mounting of the sheet cassette and (b) generating a mating resistance during the mounting in the second embodiment of the present invention; It is explanatory drawing which shows the relationship of the fitting resistance of a recessed part.

FIG. 5 illustrates a paper feed cassette and a second paper feed cassette according to a third embodiment of the present invention.
FIG. 5 is a perspective view showing a relationship between a convex portion and a second concave portion.

FIG. 6 is an explanatory diagram when a force is applied from the handle in the mounting direction before (a) and during mounting (b) of the sheet cassette shown in the second embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a relationship between a gap formed between a conveyance guide member and a sheet feeding cassette, a leading end of a fed sheet, and a second protrusion according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a state in which the leading end of a fed sheet enters a gap formed between a conveyance guide member and a sheet feeding cassette according to a fourth embodiment of the present invention.

FIG. 9 is a perspective view schematically illustrating a configuration of a sheet cassette that can be attached to and detached from a conventional image forming apparatus main body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Device main body, 1a ... Cover, 2 ... Paper feed cassette (paper feeder), 3 ... Paper feed roller, 4a ... Press roller, 4
b: pressure plate, 5: photoreceptor, 6: charging means, 7: developing means, 8: transfer means, 9: cleaning means, 10
... Cartridge, 11 ... Registration roller, 12 ... Fixing unit, 13 ... Discharge roller, 14 ... Stock unit, 15 ... Case, 16 ... Electric unit, 17 ... Power supply unit, 18 ... Optical unit,
19: paper support member, 19a: horizontal portion, 19b: vertical portion, 20: transport path, 20a: transport guide member, 20b: guide surface, 21: handle portion, 22: guide rail, 23: first concave portion, 24 ... First convex part, 25 ... Second convex part, 25
a ... rear end, 25b ... front end, 26 ... second concave part, 27 ...
Left and right stoppers, 28 ... Rear stopper.

Claims (4)

(57) [Claims] A paper cassette for storing a plurality of sheets is provided.
Feeding paper detachably installed at the bottom of the main body of the image forming apparatus
In the apparatus , a first concave portion provided in guide means of the sheet cassette at both lower ends of the image forming apparatus main body for positioning the sheet cassette in a mounting / removing direction, and bottom portions at both ends of the sheet cassette. The side wall of the paper cassette
Paper of independent and first convex portions to be fitted with the first recess provided on an outer surface substantially flush with said first recess and the first protrusion, to Cartesian and detachable direction An opening for mounting a sheet cassette of the image forming apparatus main body for performing positioning in a width direction.
A second projection provided on the upper side of a front upper portion of the paper feed cassette, the inner surface of the paper feeding cassette side walls
And a second concave portion provided inside the side wall and fitted to the second convex portion. 2. A second convex portion and a second concave portion for positioning in a sheet width direction are provided on a same straight line parallel to a handle portion provided for attaching and detaching a sheet cassette and the attaching and detaching direction of the sheet cassette. The sheet feeding device according to claim 1, wherein 3. The paper feeding apparatus according to claim 2, wherein the second convex portion and the second concave portion for positioning in the sheet width direction are located on a straight line parallel to the attaching / detaching direction passing through the center of gravity of the sheet cassette. 1
Or the paper feeder according to 2. 4. A rear end portion of the second convex portion facing the paper feed roller is flush with a guide surface of a transport guide member of the image forming apparatus main body, and protrudes downward from the transport guide member. 2. The sheet feeding device according to claim 1, wherein: