JP2002187629A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device preventing a feeding error of a thick paper sheet such as a postal card or a envelope without deteriorating separation property of a normal paper sheet. SOLUTION: This paper feeding device is provided so that angles of a paper loading plate 7 are adjustable according to the paper sheet 2 to change paper entrance angles θ. Consequently, a feeding error of a thick paper sheet 2 such as a postal card or a envelope can be prevented without deteriorating separation property of the normal paper sheet.

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 for an electrophotographic image forming apparatus such as a laser printer, PPC, FAX, and the like.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an electrostatic latent image formed on a photoreceptor is visualized by a toner of a developing device, and the visualized toner image is converted to a table on which a sheet is loaded (hereinafter, referred to as a table). (Referred to as “paper feed tray”). Next, the transferred image on the sheet is fixed on the sheet by a fixing device and discharged, thereby obtaining a final image. At this time, as a method of feeding the paper sheet one by one from the paper feed tray, a claw is provided at a corner of the leading end of the paper feed tray to buckle the paper when feeding the paper. There are a claw separation method for slipping out, and a FRR method in which a reverse roller that rotates in a direction opposite to the feed roller is provided slightly ahead of the paper feed tray and separates by using friction with paper.

However, at present, a friction pad system, which is advantageous in terms of reliability and cost, is often used. FIG.
2 and 13 are diagrams showing a configuration of a conventional sheet feeding device employing a friction pad system. The paper 2 set on the paper stacking plate 1 provided on the paper feed tray 10 is pressed by the paper feed roller 4 by the pressurizing mechanism 3 and starts to be fed by the rotation of the paper feed roller 4. The sheet is separated and transported by a friction pad 6 pressed by a spring 5. Angle θ between the paper 2 and the surface of the friction pad 6 when the leading edge of the paper 2 enters the friction pad 6
(Hereinafter referred to as “sheet entry angle θ”) varies depending on the type of the sheet 2 to be fed, the material of the friction pad 6, and the like, but is usually set to 25 to 35 °.
In general, the greater the angle of entry θ, the higher the sheet separation performance. However, when the paper entering angle θ is large, the load when the leading end of the paper 2 enters the friction pad 6 with thick paper such as a postcard or an envelope made of government increases, and there is a problem that non-feeding is likely to occur.

[0004] For this purpose, for example, Japanese Utility Model Publication No. 8-5163
Japanese Patent Application Laid-Open Publication No. Hei 11 (1995) discloses a sheet feeding device of an image forming apparatus that detects a sheet size and a sheet thickness and controls a separation pressure and a sheet feeding pressure to appropriate values. Japanese Utility Model Publication No. Hei 7-45482 discloses a friction separating mechanism of an automatic sheet feeding device that separates a friction pad from a sheet feeding roller by stiffening a sheet when passing thick paper. Further, Japanese Utility Model Publication No. Hei 8-25655 discloses an adhesive structure of a sheet separation pad of an automatic sheet feeder having a structure capable of easily converting a separation pad having a different material according to a paper type.

[0005]

SUMMARY OF THE INVENTION In order to further improve the above-mentioned problem, the present invention changes the angle of the sheet stacking plate in accordance with the sheet to change the sheet entering angle, thereby impairing the separation performance of plain paper. It is another object of the present invention to provide a sheet feeding device which is unlikely to cause a non-feed on thick paper such as a postcard or an envelope made by government. Furthermore, by automatically detecting the thickness of the paper, the angle of the paper stacking plate can be automatically changed according to the thickness of the paper, making it difficult for non-feeding of thick paper such as government-made postcards and envelopes to occur, and It is an object to provide a paper feed mechanism with good operability. In addition, by detecting the paper size, it is possible to automatically change the paper stacking plate angle when it detects that the paper size is unique to thick paper such as government postcards and envelopes. An object of the present invention is to provide a paper feed mechanism which is less likely to cause non-feed on thick paper such as a postcard or an envelope, and which has good operability. Also, mechanically linked to a paper position regulating member such as a side fence or end fence,
If the position of the paper position regulating member is a position for paper of a size specific to thick paper such as government-made postcards or envelopes, the paper stacking plate angle can be changed automatically, and non-feeding with thick paper such as government-made postcards or envelopes It is an object of the present invention to provide a paper feed mechanism that is less likely to generate paper and has good operability.

[0006]

According to a first aspect of the present invention, there is provided a paper feeder for use in an electrophotographic image forming apparatus, wherein the means for separating the paper comprises a friction pad separating system. In this case, the sheet feeding device is configured to make the inclination of the table on which the sheets are loaded variable. According to a second aspect of the present invention, in the paper feeder according to the first aspect, means for detecting the thickness of the stacked paper is provided, and when the stacked paper is detected as thick paper, the feeding is performed. Use a paper feeder that reduces the inclination of the paper tray. According to a third aspect of the present invention, in the paper feeder according to the first aspect, there is provided means for detecting a size of the stacked sheets,
If the loaded paper is detected to be of a specific size, the paper feed tray is set to have a smaller inclination.

According to a fourth aspect of the present invention, in the paper feeder used in the electrophotographic image forming apparatus, the means for separating the paper is a friction pad separation system.
A sheet feeding device is provided in which a sheet stacking plate of a table for stacking sheets has an angle variable with respect to a friction pad surface on a downstream side in a sheet conveying direction. According to a fifth aspect of the present invention, in the paper feeder according to the fourth aspect, means for detecting the thickness of the stacked sheets is provided, and when the stacked sheets are detected to be thick, the sheets are stacked. Change the angle in the direction that lifts the downstream part of the plate. Claim 6
The invention described in (5) is the paper feeder according to (5), further comprising means for detecting the size of the stacked paper,
When it is detected that the stacked sheets have a specific size, the sheet feeding device changes the angle in a direction in which the downstream portion of the sheet stacking plate is lifted. According to a seventh aspect of the present invention, in the paper feeder according to the first aspect, a regulating member for regulating a position of an end portion of the sheet is made variable on the sheet feeding bottom plate according to a sheet size, and is interlocked with the position of the regulating member. Then, the sheet feeding device changes the angle in the direction in which the downstream portion of the sheet stacking plate is lifted.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing a configuration of a sheet feeding device of the present invention. FIG. 1A is a diagram illustrating a configuration of a sheet feeding device in a state of feeding plain paper other than thick paper. The sheet feed tray (10) and the arm (11) provided integrally with the sheet feed tray engage the stopper (12) to maintain the inclination (indicated by the angle α from the horizontal in FIG. 1). The stopper (12) is provided integrally with a lever (13) rotatably provided at a fulcrum (14), and the lever (13) is pulled to the left side in the figure by a spring (15). The position is maintained by hitting (17). The solenoid (16) is not energized, and in this state, the force pulling the lever (13) toward the solenoid (16) is applied to the sheet feed tray (1).
0) and only the force due to the weight of the paper (2) loaded thereon, the angle of the paper feed tray is kept at α = 22 ° because the force of the spring (15) is sufficiently strong. The paper entering angle at this time is 35 °.

FIG. 1B is a diagram showing the configuration of the sheet feeding device in a state of feeding thick paper. At this time, the solenoid (16) is energized. When the lever (13) is pulled by the solenoid (16), the lever (1) is pulled.
3) is pulled until it hits the lever stopper B (18). The attraction force of the solenoid (16) is
Make it stronger than the force of 5). This allows
The position of the stopper (12) is changed. The angle of the paper feed tray is α = 17 ° and the solenoid (16) is 5
° becomes smaller. Thereby, the lever (13) provided integrally is pulled to the left side in the figure by the spring (15), and keeps its position by hitting the lever stopper A (17). When the solenoid (16) is not energized, the force for pulling the lever toward the solenoid is only the force due to the weight of the paper feed tray (10) and the paper (2) stacked thereon, so that the spring (1) is pulled.
5) The force is strong enough and the angle of the paper feed tray is α = 22 °
Is kept in. The paper entering angle at this time is 30 °. As described above, the paper entry angle θ can be switched between plain paper and thick paper by switching ON / OFF of the solenoid (16) according to the thickness of the paper set in the paper feed tray. Accordingly, it is possible to provide a sheet feeding device that does not deteriorate the performance of separating plain paper and hardly causes non-feeding of thick paper such as an official postcard or an envelope.

(Second Embodiment) FIG. 2 is a flowchart for operating a solenoid when the thickness of a sheet is detected. The sheet thickness of the sheet (2) set on the sheet stacking plate (1) is detected by a sheet thickness sensor (not shown) for detecting the sheet thickness. At this time, if the thickness of the sheet is equal to or greater than the specified value, the solenoid (16) is turned on, and the state shown in FIG. If the thickness of the sheet is less than the specified value, the solenoid (16) is turned off, and the state shown in FIG. Thereby, when the thick paper is set, the paper entering angle θ can be automatically reduced, and a paper feeding device that does not easily cause non-feeding can be provided.

(Third Embodiment) FIG. 3 is a flowchart for operating a solenoid when the size of a sheet is detected. The thickness of the sheet (2) set on the sheet stacking plate (1) is detected by a sheet thickness sensor (not shown) for detecting the size of the sheet. At this time, if the paper size is a specified size, the solenoid (16)
N, resulting in the state of FIG. When the paper size is out of the specified range, the solenoid (16) is turned off,
The state shown in FIG. The paper size for which the solenoid (16) is turned on is a size (postcard, envelope made by government) specific to thick paper as shown in Table 1.

[Table 1] Thereby, when a sheet of a specified size is set, the sheet entering angle θ can be automatically reduced, and a sheet feeding apparatus in which non-feeding hardly occurs can be provided.

(Fourth Embodiment) FIG. 4 is a schematic diagram showing the configuration of a sheet feeding device according to the present invention. FIG. 5 is an enlarged view showing a part of the sheet feeding device of FIG. The downstream side (paper feed roller (4) side) of the paper loading plate (1) with respect to the paper transport direction
When a member whose angle is variable with respect to the surface of the friction pad (6) (hereinafter referred to as a "front paper stacking plate") (7) is provided, and thick paper (2) such as an official postcard or an envelope is fed. Further, there is provided a mechanism for changing an angle in a direction in which the front paper stacking plate (7) is lifted. Thereby, the front paper stacking plate (7)
Is not 35 °, the sheet entering angle θ is 35 °, but as shown in FIG. 5, the sheet entering angle θ can be reduced to θ = 30 °. As a result, the paper (2) when the thick paper (2) is fed
Since the load at the time when the tip enters the friction pad (6) increases, it is possible to improve the problem that non-feeding is likely to occur.

FIG. 6 is a schematic diagram showing the structure of a mechanism for changing the angle of the front sheet stacking plate. FIG. 7 is a diagram showing a configuration when FIG. 6 is viewed from below. A fulcrum (20) is attached to a holder (21) having a lever (19) fixed to the sheet stacking plate (1).
And rotatably provided. A boss (22) is provided integrally with the lever (19), and the rotation of the lever (19) causes the slide member (23) to move in the left-right direction in FIG. When the slide member (23) is on the left side as shown in FIG. 7B, the protrusion (2) provided on the front sheet stacking plate (7) is used.
Since 4) is pushed upward by the slide member (23), as shown in FIG. 6, the front paper stacking plate (7) is raised, and the paper entering angle θ is reduced. When the slide member (23) is on the right side as shown in FIG. 7A, the protrusion (24) provided on the front sheet stacking plate (7) is separated from the slide member (23). The front paper loading plate (7) is not lifted, and the paper entering angle θ does not change. This makes it possible to change the angle of the paper loading plate according to the paper and change the paper entry angle θ, so that the separation performance of plain paper is not impaired, and thick paper such as government-made postcards and envelopes And a sheet feeding device that is unlikely to cause non-feeding.

(Fifth Embodiment) FIG. 8 is a schematic diagram showing the structure of a mechanism for changing the angle of the front sheet stacking plate. FIG.
FIG. 9 is a diagram showing a configuration when FIG. 8 is viewed from below. The lever (2) is rotatable about the fulcrum (29) on the paper loading plate (1).
5), and the lever (25) is provided with a spring (30).
Accordingly, as shown in FIG. 9A, the wire is pulled downward, and a solenoid (31) is provided on the opposite side. When the solenoid (31) is not energized, the lever (2) is pulled by the spring (30).
5) is at a position corresponding to the stopper (27). At this time, since the projection (24) provided on the front paper stacking plate (7) is separated from the slide member (23), the front paper stacking plate (7) is not lifted, and the paper entering angle is not increased. θ does not change.

When the solenoid (31) is energized, the position of the lever (25) is changed by suction of the solenoid (31) as shown in FIG. 9 (b), and the lever (25) is provided on the front sheet stacking plate (7). Since the raised portion (24) is pushed upward by pressing, the front paper stacking plate (7) as shown in FIG.
Is lifted, and the paper entry angle θ decreases. The solenoid (31) is energized by the loaded paper (2).
This is when the thickness of the sheet (2) is detected to be greater than a reference value by a sheet thickness sensor (not shown) for detecting the thickness of the sheet (2). As a result, when thick paper (2) such as an official postcard or an envelope is loaded, the solenoid (31) is energized, so that the entry angle θ of the paper is reduced, thereby preventing the use of thick paper such as an official postcard or an envelope. It is possible to provide a sheet feeding device that does not easily cause feeding.

(Sixth Embodiment) Here, a description will be given with reference to FIGS. 8 and 9 as in the fifth embodiment. A lever (25) is provided on the paper loading plate (1) so as to be rotatable around a fulcrum (29), and this lever (25) is pulled downward by a spring (30) as shown in FIG. On the opposite side, a solenoid (31) is provided. When the solenoid (31) is not energized, the lever (25) is in a position where it comes into contact with the stopper (27) due to the pulling force of the spring (30). At this time, since the protrusion (24) provided on the front paper stacking plate (7) is separated from the slide member (23), the front paper stacking plate (7) is separated.
Is not lifted, and the paper entering angle θ does not change.

When the solenoid (31) is energized, as shown in FIG. 9 (b), the position of the lever (25) is changed by suction of the solenoid (31), and the lever (25) is mounted on the front sheet stacking plate (7). Since the raised convex portion (24) is pushed upward and raised, as shown in FIG. 8, the front paper stacking plate (7) is raised, and the paper entering angle θ is reduced. The solenoid (31) is energized when it detects that the size of the loaded paper (2) is a specified size. The specified size here is a paper size specific to thick paper such as government-made postcards and envelopes, as shown in Table 1 described above. As a result, when thick paper (2) such as an official postcard or an envelope is loaded, the solenoid (31) is energized, so that the entering angle θ of the paper is reduced, and the thick paper (2) such as an official postcard or an envelope is used. It is possible to provide a sheet feeding device that does not easily cause non-feeding.

(Seventh Embodiment) FIGS. 9 and 10 are schematic diagrams showing the configuration of a sheet feeding apparatus according to the present invention. A side fence (32) that regulates the left and right positions with respect to the paper transport direction
a, 32b) are connected by a pinion gear (33) so that the left and right side fences (32a, 32b) move in conjunction with each other. In the side fence (32b), a member (hereinafter, referred to as a "push-up member") for pressing the convex portion (24) provided on the front sheet stacking plate (7) (34).
Are provided integrally. Here, as shown in FIG. 11B, for example, side fences (32a, 32b)
When the width between the sheets is 110 mm or less (generally, paper frequently used with a width of less than this width is an official postcard or envelope).
The push-up member (34) pushes the convex portion (24), and the front sheet stacking plate (7) is lifted, so that the sheet entering angle θ decreases. In the case of paper (2) of other size, FIG.
(A) (In this figure, for example, the side fence (32
a, 32b) 210 mm = A4 size paper is set vertically to the width when set. ), Since the push-up member (34) is separated from the projection (24),
The front paper stacking plate (7) is not lifted, and the paper entering angle θ does not change.

[0019]

As described above, the paper feeder according to the first and fourth aspects is provided so that the angle of the paper loading plate can be changed according to the paper to change the paper entrance angle θ. Therefore, it is possible to provide a sheet feeding device that does not deteriorate the performance of separating plain paper and hardly causes non-feeding of thick paper such as an official postcard or an envelope. Also,
In the paper feeding device according to the second and fifth aspects, by automatically detecting the thickness of the paper, the angle of the paper stacking plate can be automatically changed according to the thickness of the paper. As a result, it is possible to provide a paper feed mechanism that does not easily cause non-feeding of thick paper and has good operability. Further, in the paper feeding device according to the third and sixth aspects, by detecting the paper size, it is possible to detect when the paper size is a paper having a size specific to thick paper such as an official postcard or an envelope. In addition, the paper stacking plate angle can be automatically changed, a non-feeding of thick paper such as a postcard or an envelope made of government is hard to occur, and a paper feeding mechanism with good operability can be provided. Further, in the paper feeding device according to the seventh aspect, the position of the paper position regulating member is mechanically linked with a paper position regulating member such as a side fence or an end fence, and the position of the paper position regulating member is a size specific to thick paper such as an official postcard or an envelope. In this position, the paper stacking plate angle can be automatically changed, and non-feeding of thick paper such as postcards and envelopes is difficult to occur, and a paper feed mechanism with good operability can be provided. it can.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a sheet feeding device of the present invention.

FIG. 2 is a flowchart for operating a solenoid when the thickness of a sheet is detected.

FIG. 3 is a flowchart for operating a solenoid when a sheet size is detected.

FIG. 4 is a schematic diagram illustrating a configuration of a sheet feeding device of the present invention.

FIG. 5 is an enlarged view showing a part of the sheet feeding device of FIG. 4;

FIG. 6 is a schematic diagram showing a configuration of a mechanism for changing an angle of a front paper stacking plate.

FIG. 7 is a diagram showing a configuration when FIG. 6 is viewed from below.

FIG. 8 is a schematic diagram showing a configuration of a mechanism for changing an angle of a front paper stacking plate.

9 is a diagram showing a configuration when FIG. 8 is viewed from below.

FIG. 10 is a schematic diagram illustrating a configuration of a sheet feeding device of the present invention.

FIG. 11 is a schematic diagram illustrating a configuration of a sheet feeding device of the present invention.

FIG. 12 is a diagram showing a configuration of a conventional paper feeding device employing a friction pad system.

FIG. 13 is a diagram showing a configuration of a conventional sheet feeding device employing a friction pad system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper loading plate 2 paper 3 pressure mechanism 4 paper feed roller 5 spring 6 friction pad 7 front paper loading plate 10 paper feed tray 11 arm 12 stopper 13 lever 14 fulcrum 15 spring 16 solenoid 17 lever stopper A 18 lever stopper B 19 Lever 20 Support point 21 Holder 22 Boss 23 Slide member 24 Convex part 25 Lever 27 Stopper 29 Support point 30 Spring 31 Solenoid 32a, 32b Side fence 33 Pinion gear 34 Push-up member

Continued on the front page F term (reference) 3F048 AA02 AA04 AA05 AB01 BA14 BA20 BB02 BB05 BD07 CA02 CA03 DA01 EB12 3F343 FA02 FB02 FB03 FB04 FC01 GA03 GB01 GC01 GD01 HA12 HD08 HD09 HD10 HD18 JA01 LC02 LC04 LC19 LD04 LD11 LD25 MA03 MB03 MA03 MC05 MC07 MC19 MC21 MC30

Claims (7)

[Claims] 1. A sheet feeding device used in an electrophotographic image forming apparatus, wherein a means for separating sheets is a friction pad separating method, and a tilt of a table on which sheets are stacked is made variable. Paper equipment. 2. The paper feeding device according to claim 1, further comprising means for detecting the thickness of the stacked paper, and tilting the paper feeding tray when detecting that the stacked paper is thick paper. Paper feeder, characterized in that the paper feed is reduced. 3. The paper feeding device according to claim 1, further comprising: means for detecting the size of the stacked paper, and when the stacked paper is detected to be a specific size,
A sheet feeding device characterized in that the inclination of the sheet feeding tray is reduced. 4. A sheet feeding device used in an electrophotographic image forming apparatus, wherein the means for separating sheets is of a friction pad separating type, and a sheet stacking plate of a table for stacking sheets in a sheet conveying direction. A sheet feeding device characterized in that an angle with respect to a friction pad surface is variable on a downstream side. 5. The sheet feeding device according to claim 4, further comprising means for detecting a thickness of the stacked sheets, and a downstream portion of the sheet stacking plate when the stacked sheets are detected to be thick sheets. A paper feed device characterized by changing the angle in the direction in which the paper is lifted. 6. The paper feeding device according to claim 5, further comprising: means for detecting the size of the stacked paper, and when it is detected that the stacked paper has a specific size,
A sheet feeding device, wherein the angle is changed in a direction in which a downstream portion of a sheet stacking plate is lifted. 7. A paper feeder according to claim 1, wherein a regulating member for regulating the position of the end of the paper is made variable on the paper supply bottom plate in accordance with the size of the paper, and the paper is stacked in conjunction with the position of the regulating member. A sheet feeding device characterized by changing an angle in a direction of lifting a downstream portion of a plate.