JP2001122450A - Sheet feeding device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sense if a sheet can be fed or not by a feed roller prior to feeding by the feed roller. SOLUTION: The sheet feeding device comprises a sheet stacking table 7 for stacking sheets P, a feed roller 2 abutting to the uppermost sheet of the stacked sheets on the table 7 for feeding it, and a sheet abutting member 3 having an abutting part 3a abutting to the uppermost sheet on the table 7 and vertically moving in compliance with the sheet amount stacked on the table 7. The abutting part of the sheet abutting member is positioned on a virtual line of sheet feed direction passing a position near the feed roller and approximately in the center across the width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus and an image forming apparatus including the sheet feeding apparatus, such as a printer, a copying machine, and a facsimile.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a copying machine, a printer, and a facsimile which forms an image on a sheet material such as a copy sheet by an image forming means, a sheet comprising a loading table or the like for loading a plurality of sheet materials. A stacking device is detachably attached to a main body of the image forming apparatus, and sheet materials stacked on the sheet stacking device are sequentially picked up by a feeding roller or the like from a topmost one, and a sheet conveying path connected to the image forming means. To be sent to
These constitute a sheet feeding device.

[0003] The configuration of a conventional sheet feeding apparatus and an image forming apparatus having the same will be described below. FIG. 6 is a cross-sectional view illustrating an example of a conventional image forming apparatus, and is a view illustrating a schematic configuration of a laser beam printer as an image forming apparatus to which a sheet stacking apparatus main body 1, which is a housing on the sheet stacking and feeding apparatus side, is mounted. It is.

In this laser beam printer, a lever 33 as a sheet detecting means for detecting the presence or absence of a sheet material in a printer main body 101 as a housing and a lever detection sensor 34 described later, and a laser beam printer mounted in the sheet stacking apparatus main body 1. A feeding roller 12 for feeding the fed sheet material, a separation pad 6 for separating the fed sheet material, a conveying roller pair 102 as a conveying means for conveying the sheet material, a registration roller pair 103, A laser scanning optical unit 105 for irradiating the photosensitive drum 104 with an optical image corresponding to the image information;
Process cartridge 106 having photosensitive drum 104
A transfer unit having a transfer roller 107 for transferring a toner image developed by a developing material (hereinafter, referred to as toner) on the photosensitive drum 104 to a sheet material, and an unfixed toner image on the sheet material Roller 108 for fixing
And a pressure roller 109, and a discharge roller pair 110 for discharging the fixed image to the outside of the printer main body.

Next, the structure of a conventional sheet feeding device provided in the laser beam printer will be described.
FIG. 7A is a perspective view showing a sheet feeding apparatus when the sheet stacking apparatus main body 1 is mounted on the printer main body 101, and FIGS. 7B and 7C are arrows in FIG. 7A, respectively. FIG. 3 is a cross-sectional view of the sheet feeding device as viewed from a direction A and a direction B.

In this sheet feeding apparatus, the feeding roller 12 is mounted on a roller driving shaft (not shown) rotatably supported on the printer main body 101 side. The roller drive shaft is located in a direction perpendicular to the feeding direction of the sheet material stacked in the sheet stacking device main body 1,
Feed rollers 5 are attached to both end sides of the roller. A substantially L-shaped lever 33 for detecting the presence or absence of a sheet material is rotatably supported by a support portion (not shown) of the printer main body 101. A sensor 34 is provided.

A sheet stacking plate 37 provided with a relief hole 37a is provided inside the sheet stacking apparatus main body 1, and the sheet material P is stacked on the sheet stacking plate 37.
Further, a side regulating plate 8 which is a sheet material regulating member is provided parallel to the feeding direction of the sheet material P loaded on the sheet loading plate 37 and opposed to both side surfaces of the sheet material P, and is provided rearward in the sheet material conveying direction. The portion is provided with the separation pad 6 of FIG.

Hereinafter, the operation of a laser beam printer equipped with a conventional sheet feeding device will be described. As shown in FIG. 6, the sheet stacking plate 37 of the sheet stacking device main body 1
The sheet material P stacked on the feed roller 12 is rotated by the roller drive shaft in the direction of arrow G based on a control signal from a control unit (not shown), and the feed roller 12 is rotated. The sheet is fed and conveyed by friction with the sheet material P. The conveyed sheet material P is separated by only one uppermost sheet material by the action of the separation pad 6 provided on the downstream side in the conveyance direction, and then conveyed sequentially to the conveyance roller pair 102 and the registration roller pair 103. You.

The sheet material P is conveyed by a pair of registration rollers 103 in accordance with the rotation of a photosensitive drum 104 as an electrophotographic photosensitive member disposed in a process cartridge 106 serving as a recording means.
As a result, the toner image on the photosensitive drum 104 is transferred onto the sheet material P. Subsequently, the sheet material P is transferred to the fixing roller 10.
The toner image on the sheet material P is fixed as a permanent image by being heated and pressed by a roller pair of the roller 8 and the pressing roller 109. Thereafter, the sheet material P is discharged onto the discharge receiving portion 113 by the discharge roller pair 110.

Here, the lever 3 in the sheet feeding apparatus is used.
A configuration for detecting the position of No. 3 will be described. As shown in FIG. 7, a lever detection sensor 34 is provided near the lever 33. The lever detection sensor 34 includes a transmission type or reflection type photo sensor including a light emitting element and a light receiving element, and an electric contact. Generally, general-purpose electrical components such as microswitches that detect positions by open / short are used.

In this example, a transmission type photosensor is used for the lever detection sensor 34, and FIGS. 8A to 8C show the lever detection sensor 34 and the lever 33 from the side.
(D) is shown from the front side. Lever detection sensor 34
8 can output the position of the lever 33 as an electric signal using the position of the imaginary line A in FIG. 8 as a threshold value. As shown in FIG. It is possible to discriminate between the case of entering the inside and the case of the lever 33 going out of the threshold as shown in FIG.

Hereinafter, the operation and function of the lever 33 and the lever detection sensor 34 provided in the conventional sheet feeding apparatus will be described. FIGS. 9A and 9B are enlarged views of the sheet detecting means viewed from the side of the main body 1 of the sheet stacking apparatus. When the sheet stacking apparatus main body 1 is mounted on the laser beam printer main body 101, the lever 33 shown in FIG.
Of the lever member 33a comes into contact with the uppermost sheet material, the lever 33 enters the threshold value (virtual line A) of the lever detection sensor 34, and the sheet material P is placed on the sheet stacking plate 37 of the sheet stacking apparatus main body 1. Is present, and the detection sensor 34 outputs a signal to that effect.

On the other hand, as shown in FIG. 9B, when the sheet material on the sheet stacking plate 37 runs out due to continuous feeding of the sheet material or the like, the lever 33 is moved in the direction of the arrow B by its own weight or a separately provided spring force. , And the leading end portion 33a enters the lower portion of the relief hole 37a provided in the sheet stacking plate 37. As a result, when the lever 33 goes out of the threshold value of the lever detection sensor 34, it is determined that the sheet material P does not exist on the sheet stacking plate 37 of the sheet stacking apparatus main body 1, and a signal to that effect is sent from the detection sensor 34. Is output.

As described above, in the conventional sheet feeding apparatus and the image forming apparatus provided with the same, the presence of the sheet material in the sheet stacking apparatus main body 1 can be detected by the operation of the lever 33 and the lever detection sensor 34. The control unit makes the display unit such as a display perform various displays based on the detection result, thereby prompting the user to replenish the sheet material.

[0015]

However, the conventional configuration has the following problems.

[0016] In recent years, laser beam printers have become widespread and are used in various environments around the world. Along with this, when the condition of the sheet material used is poor, a printer capable of handling a sheet material that is left particularly in a humid environment and has a wavy edge has been required. .

FIG. 10 is a view when the sheet material whose edges are wavy is left on the sheet stacking apparatus main body 1 when the sheet material is left under a high humidity condition, as viewed from the direction of arrow A in FIG. 1
0 (a) is a feed roller 1 near the concave portion of the wavy sheet material.
2 shows the case where it is located. At this time, a gap X between the feeding roller 12 and the sheet material P was generated near the center of the feeding roller 12, and the feeding roller 12 could not contact the sheet material P and could not be fed. This state occurs when a large amount of corrugated sheet material is stacked on the sheet stacking apparatus main body 1 (hereinafter, referred to as full load), and is particularly remarkable when highly rigid cardboard is used as the sheet material. there were.

As a conventional measure which has been taken as a measure against the feeding failure, if the sheet cannot be fed, the loaded sheet material P is turned upside down.
As shown in FIG. 0B, when the concave and convex portions of the wavy sheet material are reversed, the gap between the feeding roller 12 and the sheet material P is eliminated, and the sheet material P is subjected to frictional force from the feeding roller 12. It is possible to receive.

However, according to the configuration of the conventional sheet feeding apparatus, when the sheet cannot be fed due to the use of the wavy sheet material, the cause of the wavy sheet is provided unless the user reads the manual in detail. It could not be determined that the material was used. Therefore, in the configuration of the conventional sheet feeding apparatus, the main body of the printer stops even though the sheet material P is stacked in the main body 1 of the sheet stacking apparatus.
In many cases, the user assumed that the failure was in the printer body.

A first object of the present invention is to solve the above-mentioned problems, and a sheet feeding apparatus capable of detecting whether or not a sheet material can be fed by a feeding roller prior to feeding, and a sheet feeding apparatus therefor. An image forming apparatus provided with:

A second object of the present invention is to solve the above-mentioned problems by providing a sheet feeding apparatus having a feeding roller and a sheet presence / absence detecting means for detecting the presence / absence of a sheet material. An object of the present invention is to provide a sheet feeding apparatus capable of detecting whether or not a sheet material can be fed by a feeding roller using a sheet presence / absence detecting unit and an image forming apparatus having the same with a simple configuration similar to the related art. .

[0022]

A first configuration of a sheet feeding apparatus according to the present invention that achieves a first object includes a sheet loading table on which a sheet material is loaded, and a sheet loading table loaded on the sheet loading table. It has a feeding roller that contacts the upper sheet material and feeds the sheet material, and a contact portion that contacts the uppermost sheet material on the sheet loading table, according to the loading amount of the sheet material on the sheet loading table. A sheet abutting member that moves up and down, wherein the abutting portion is disposed on an imaginary line in the sheet feeding direction that passes through a position near the feeding roller and substantially at the center in the width direction. And

According to a second configuration of the sheet feeding apparatus according to the present invention that achieves the first object, a sheet loading table on which a sheet material is loaded is arranged coaxially with each other and loaded on the sheet loading table. A pair of feed rollers that abut on the uppermost sheet material and feed the sheet material, and a contact portion that abuts on the uppermost sheet material on the sheet loading table. A sheet abutting member that moves up and down in accordance with the stacking amount, wherein the sheet abutting member is arranged such that the abutting portion is located in a gap between the respective feeding rollers.

According to a third configuration of the sheet feeding apparatus according to the present invention that achieves the first object, in the first or second configuration, a detection signal corresponding to a position of a contact portion of a sheet contact member is provided. It has a sensor for outputting.

According to a fourth configuration of the sheet feeding apparatus according to the present invention that achieves the first object, in the third configuration, the presence or absence of a sheet material on a sheet stacking table is detected based on a detection signal of a sensor. And a sheet presence / absence detecting means.

A first configuration of a sheet feeding apparatus according to the present invention that achieves the second object includes a sheet loading table on which a sheet material is loaded, and a top sheet material loaded on the sheet loading table. In a sheet feeding apparatus including a feed roller that contacts and feeds a sheet material and a sheet presence / absence detection unit that detects presence / absence of the sheet material on the sheet loading table, the sheet presence / absence detection unit includes A sheet contact member having a contact portion that contacts the top sheet material and moving up and down according to the amount of sheet material loaded on the sheet stacking table; and detection according to the position of the contact portion of the sheet contact member A sensor for outputting a signal, wherein the sheet contact member is arranged on an imaginary line in the sheet feeding direction in which the contact portion passes near the feeding roller and substantially at the center in the width direction.

A second configuration of the sheet feeding apparatus according to the present invention that achieves the second object is that a sheet loading table on which a sheet material is loaded is arranged coaxially with each other and loaded on the sheet loading table. A pair of feed rollers for feeding the sheet material in contact with the uppermost sheet material, and sheet presence / absence detection means for detecting the presence / absence of the sheet material on the sheet stacking table. A sheet contact member having a contact portion that contacts the uppermost sheet material on the loading table and moving up and down according to the amount of sheet material loaded on the sheet loading table; and a position of the contact portion of the sheet contact member And a sensor that outputs a detection signal corresponding to the sheet feeding roller, wherein the sheet contact member is disposed such that the contact portion is located in a gap between the respective feeding rollers.

The sensor in the sheet feeding device feeds the sheet material by causing the contact portion of the sheet contact member to contact the sheet material of the feeding roller based on the deformation of the sheet material loaded on the sheet stacking table. An error signal is output when the position is relatively lower than the position where the error occurs.

In this case, an error display means for displaying an error indicating that feeding is impossible based on an error signal from the sensor is provided.

Further, drive control means for controlling the drive of the feed roller is provided, and the drive control means controls the drive of the feed roller so as to prohibit the feeding of the sheet material when an error signal is output from the sensor. Take control.

The sheet loading table in the sheet feeding device is
It is good also as composition provided with the hole into which the contact part of a sheet contact member enters.

In order to achieve the first or second object, the image forming apparatus according to the present invention includes a sheet feeding device having any one of the above-described configurations, and an image forming device that prints an image on a sheet material fed by the sheet feeding device. Image forming means for forming.

[0033]

Embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiment, an example of a sheet feeding apparatus applied to the laser beam printer described with reference to FIG. 6 will be described, and a schematic configuration of the laser beam printer, and image printing after feeding and printing up to discharge will be described. Since the operation is as described above, the description is omitted, and FIGS. 6 and 7 are referred to as needed.

(First Embodiment) FIG. 1 (a) is a perspective view of a sheet feeding apparatus according to a first embodiment of the present invention. FIG. 9 is a diagram when a corrugated sheet material is stacked on a sheet stacking device main body. FIGS. 1B and 1C are cross-sectional views of the sheet feeding apparatus viewed from the direction of arrow A (the direction of feeding the sheet material) and the direction B (the width direction of the sheet material) in FIG. is there.

As shown in FIG. 1, the sheet feeding device includes a sheet stacking device main body 1 as a housing, a sheet stacking plate 7 on which sheets are stacked, and a sheet stacking plate 7 on which the sheets are stacked. A side regulating plate 8 for adjusting the posture, a feed roller 2 for abutting on the uppermost sheet material stacked on the sheet stacking plate 7 to feed the sheet material, and a sheet roller stacked on the sheet stacking plate 7; A lever 3 serving as a sheet contact member having a contact portion 3a contacting a higher-order sheet material and moving in accordance with the amount of the sheet material on the sheet stacking plate 7, and a lever detection sensor for detecting the position of the lever 3 And control means (not shown) (not shown) for controlling the operation of these units.
And

The sheet stacking apparatus main body 1 is detachably attached to the printer main body 101 of the laser beam printer shown in FIG. In the sheet stacking apparatus main body 1, a sheet stacking plate 7 and a side regulating plate 8 are movably arranged. In this embodiment, the feed roller 2, the lever 3, and the lever detection sensor 4 are attached to the printer main body 101.

The sheet stacking plate 7 is rotatable up and down in the sheet stacking apparatus main body 1 about a fulcrum 7s on the base end side. The sheet material is not stacked by a biasing means (not shown). In the state, the front end side comes into contact with the feeding roller 2 or the feeding roller 5. Also, the sheet stacking plate 7
Is provided with a relief hole 7a at the approximate center position on the distal end side for the contact portion 3a of the lever 3 to enter.

The side regulating plate 8 is used to hold the sheet stacking device main body 1.
Is mounted so as to be able to reciprocate in the width direction with respect to the sheet material, and the position of the sheet material is adjusted so as to come into contact with the side surface of the sheet material stacked on the sheet stacking plate 7, thereby adjusting the posture of the sheet material. .

In this embodiment, a pair of feed rollers are mounted on a roller drive shaft (not shown). Here, each of the feeding rollers 2 and 2 has a substantially half-moon-shaped cross-sectional shape, and has a feeding surface 2a for feeding a sheet material;
And a standby surface 2b that faces the sheet material in an initial state before feeding. At the lower position facing each of the feed rollers 2, 2, a sheet material stacked on the sheet stacking plate 7 is not separated when the feed rollers 2, 2 separate the sheets into one sheet. The illustrated separation pad (see FIG. 6) is provided.

A pair of feed rollers 5 are attached to roller drive shafts outside the feed rollers 2 and 2. As shown in FIG. 1C, each of the feed rollers 5 and 5 is a substantially circular member having a diameter slightly smaller than that of the feed roller 2.
When the standby surface 2b of the second roller 2 is opposed to the sheet material, the standby surface 2b abuts on the uppermost sheet material and each of the feed rollers 2, 2
Has a function of separating the standby surface 2b from the sheet material so as not to contact with the sheet surface.

In the sheet feeding apparatus, the roller driving shaft is driven to rotate by a motor (not shown) from the initial state shown in FIG. And the respective feeding rollers 5, 5 rotate integrally, and when the feeding surface 2a of each of the feeding rollers 2, 2 comes into contact with the sheet material, the contact between the sheet material and each of the feeding rollers 5, 5 is changed. When released, each of the feed rollers 2 rotates once to feed the uppermost sheet material stacked on the sheet stacking plate 7 by a predetermined distance.

The lever 3 has a generally L-shaped outer shape,
It is rotatably attached to the printer main body 101 side around the fulcrum 3s. Here, the lever 3 is shown in FIG.
As shown in (a), the contact portion 3a on the leading end side is disposed so as to be located in the gap between the feed rollers 2 and 2.

The lever detection sensor 4 is, for example, a transmission type photo sensor, and is disposed so as to cover a tip portion of the lever 3 on the side opposite to the contact portion 3a. An error signal is output when a line is crossed. The signal from the lever detection sensor 4 is supplied to the CPU.

In the sheet feeding apparatus according to the present embodiment, the contact portion 3a of the lever 3 is provided so as to enter the gap between the feeding rollers 2 and 2, as shown in FIG. ,
The position of the uppermost sheet material P on the sheet stacking plate 7 is detected in the outer peripheral cylinder of the feed roller 2 which is very close to the contact position between the feed roller 2 and the sheet material P.

Next, the threshold line of the lever detection sensor 4, the operation of the sheet feeding device in each state of the sheet material stacked on the sheet stacking plate 7, and the like will be described with reference to FIG.

FIG. 2A is a diagram for explaining the threshold value of the lever detection sensor 4. In the sheet feeding device, the outer circumference of the feeding roller 2 (the lowest point of the feeding surface 2a of the feeding roller 2).
When the contact portion 3a of the lever 3 comes into contact with a tangent line H contacting the ridge line 3b, the ridgeline 3b at the tip end opposite to the contact portion 3a of the lever 3
The positions of the lever 3 and the lever detection sensor 4 are determined so that the position of the lever 3 and the threshold line A of the lever detection sensor 4 overlap.

FIG. 2B is a diagram when a normal normal sheet material is stacked on the sheet stacking plate 7, and the position of the uppermost sheet material is indicated by a reference line M. In this case, as can be understood from comparison with FIG. 2A, since the reference line M comes to a position higher than the tangent line H, the lever 3 enters the threshold line A and the outer peripheral cylinder of the feeding roller 2 Is considered to be the uppermost sheet material, and the lever detection sensor 4 outputs a signal to that effect to the CPU.

Next, FIG. 2 (c) shows the state when the sheet material on the sheet stacking plate 7 is exhausted or when the sheet stacking plate 7
FIG. 3 is a diagram when the sheet stacking apparatus main body 1 is mounted on the printer main body 101 without loading a sheet material on the printer body 101. If there is no sheet material on the sheet stacking plate 7, the leading end side of the lever 3 enters the escape hole 7a of the sheet stacking plate 7, and the contact portion 3a of the lever 3 is located below the sheet stacking plate 7. The ridge line 3b of the lever 3 goes outside the threshold line A of the lever detection sensor 4, and it is considered that there is no sheet material that can be fed by the feed roller 2. In this case, the lever detection sensor 4
Outputs an error signal to the CPU.

FIG. 2D shows a case where a sheet material whose end is wavy is stacked on the sheet stacking plate 7, and the sheet material cannot be fed by the feeding roller 2, or It is sectional drawing shown about the case where a defect arises. In such a case, when the position of the uppermost sheet material with which the contact portion 3a of the lever 3 contacts is indicated by a reference line L, FIG.
As can be seen from comparison with FIG.
Ridge 3b of the lever 3 goes outside the threshold line A. Therefore, also in this case, it is considered that there is no sheet material that can be fed by the feeding roller 2, and the lever detection sensor 4 outputs an error signal to the CPU.

As described above, according to the sheet feeding apparatus of the present embodiment, the sheet stacking plate 7 is switched between a state in which the sheet material is stacked on the sheet stacking plate 7 and the sheet can be fed, and a state in which the sheet material cannot be fed. Two states, that is, when no sheet material is loaded on the sheet 7 and when feeding is not possible even when the sheet material is loaded, can be detected.

Therefore, in the sheet feeding apparatus or the image forming apparatus including the sheet feeding apparatus, when an error signal is output from the lever detection sensor 4 in a feeding disabled state using a display unit such as a display. And CPU
Controls the display means to display, for example, an error message indicating that "paper cannot be fed because paper is missing or paper is wavy", and it is possible to inform the user of a feed disabled state. Further, the display means may display "Replenish if paper is missing, replace or replace paper if paper is present" and give the user an instruction to clear the error. It becomes possible.

Further, in the sheet feeding apparatus or the image forming apparatus having the sheet feeding apparatus, when an error signal is output from the lever detection sensor 4 in the feeding disabled state, the rotation of the feeding roller 2 is performed. By controlling the CPU to prohibit driving, image forming operation, and the like, it is possible to prevent the occurrence of a jam, skewing, printing failure, and the like due to a feeding failure of the sheet material in advance.

As described above, the sheet feeding apparatus according to the present embodiment has the conventional function of detecting the presence or absence of a sheet material in the sheet stacking apparatus main body 1 and additionally has the function of detecting a sheet material having a wavy edge. In the case where sheets are stacked, it can be detected that there is no sheet material in the outer peripheral cylinder of the feeding roller 2. Therefore, even if there is a sheet material in the main body 1 of the sheet stacking device, it is possible to inform the user that the sheet cannot be fed, and a very easy-to-use sheet feeding device can be realized with a very simple configuration similar to the related art. It is possible to do.

(Second Embodiment) Next, a second embodiment of the sheet feeding apparatus will be described with reference to FIG.

FIG. 3 (a) is a perspective view showing a second embodiment of the sheet feeding apparatus, in which the sheet is in a poorly left state (particularly in a humid environment) and has a wavy sheet end. But,
This shows a case where the sheet is fully loaded on the sheet stacking apparatus main body. FIGS. 3B and 3C are cross-sectional views of the sheet feeding device viewed from the direction of arrow A (the direction of feeding the sheet material) and the direction B (the width direction of the sheet material) in FIG. is there.

In the sheet feeding apparatus according to the second embodiment, as apparent from FIG. 1, the configuration of the feeding roller, the position of the lever, the lever detection sensor, and the position of the relief hole of the sheet stacking plate are different. This is different from the first embodiment. Hereinafter, the same portions as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

The feeding roller 12 according to the second embodiment has a substantially half-moon-shaped cross-sectional shape like the feeding roller 2 according to the first embodiment, and is used for feeding a sheet material. Surface 12a
And a standby surface 12b opposed to the sheet material in an initial state before feeding, but in the present embodiment, one is attached to a roller drive shaft (not shown) and has a long shape in the width direction. It has become. A separation pad (not shown) for separating the sheet material stacked on the sheet stacking plate 17 into one sheet at the time of feeding by the feeding roller 12 is provided at a lower position facing the feeding roller 12. 6 (see FIG. 6).

In the sheet feeding apparatus, the roller driving shaft is driven to rotate by a motor (not shown) from the initial state shown in FIG. 3 so that the feeding roller 12 and the feeding rollers located at both ends of the feeding roller 12 are rotated. When the feeding surface 12a of the feeding roller 12 comes into contact with the sheet material, the contact between the sheet material and each of the feeding rollers 5, 5 is released, and the feeding roller 12 is rotated. The uppermost sheet material stacked on the sheet stacking plate 17 after one rotation is fed by a predetermined distance.

The lever 13 in the present embodiment has a substantially L-shaped outer shape and is rotatably mounted on the printer main body 101 side around the fulcrum 13s. Here, as shown in FIG. 3A, the lever 13 has an abutting portion 13a on the front end side provided near the feeding roller 12 and at the center rear in the width direction.

As the lever detection sensor 14, for example, a transmission type photo sensor is used.
It is arranged so as to cover the tip part on the opposite side to the point a, and outputs an error signal when the ridgeline 13b of the part exceeds a predetermined threshold line. The threshold line of the lever detection sensor 14, the operation of the sheet feeding device in each state of the sheet material stacked on the sheet stacking plate 17, and the like are the same as those in the first embodiment described above with reference to FIG. This is the same, and the description is omitted.

In this embodiment, as shown in FIG. 3 (c), the contact portion 13a of the lever 13 contacts the uppermost sheet material on the sheet stacking plate 17 slightly behind the feed roller 12. , The position of the uppermost sheet material is detected. Also,
When no sheet material is stacked on the sheet stacking plate 17, the abutting portion 13 a of the lever 13 enters into the relief hole 17 a provided on the sheet stacking plate 17.

In the second embodiment, since the contact portion 13a of the lever 13 contacts the sheet material outside the outer peripheral cylinder of the feed roller 12, the detection accuracy is slightly inferior to that of the first embodiment. However, the number of feed rollers is one as in the conventional example shown in FIG. 7, and the configuration of the feed rollers does not need to be changed, and the position of the lever, the lever detection sensor, and the relief hole of the sheet stacking plate is determined. Since only a change is required, a user-friendly sheet feeding apparatus with a very simple configuration similar to the conventional one can be provided.

(Third Embodiment) Next, FIGS.
A third embodiment of the sheet feeding apparatus will be described with reference to FIG.

FIG. 4 is a perspective view of a sheet feeding device according to a third embodiment of the present invention. The sheet feeding device has a poor standing state (especially in a humid environment), and a sheet material having a wavy sheet end portion. FIG. 7 is a diagram when the sheet is fully loaded in the sheet stacking device main body. FIGS. 4B and 4C are cross-sectional views of the sheet feeding apparatus viewed from the direction of arrow A (the direction of feeding the sheet material) and the direction of B (the width direction of the sheet material) in FIG. is there.

The sheet feeding apparatus according to the third embodiment has a configuration in which a lever, a lever detection sensor, and two relief holes for a sheet stacking plate are provided, as is clear from FIG. However, the present embodiment is different from the first embodiment. Hereinafter, the same portions as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

The feed rollers 2 and 3 in the third embodiment
2 has the same configuration as that of the first embodiment. In the third embodiment, a lever as a sheet contact member that moves in accordance with the stacking amount of the sheet material on the sheet stacking plate 27 is provided at the same position as the first embodiment. And the second lever 33 disposed at the same position as the conventional sheet feeding apparatus described with reference to FIG. Accordingly, the first lever detection sensor 4 that detects the position of the first lever 3 is also the first lever detection sensor.
The second lever detection sensor 34 for detecting the position of the second lever 33 is disposed at the same position as that of the conventional sheet feeding apparatus described with reference to FIG. An escape hole 27b into which the contact portion 3a of the first lever 3 enters is arranged at the same position as in the first embodiment,
A relief hole 27a into which the contact portion 33a of the second lever 33 enters is arranged at the same position as the conventional sheet feeding device described with reference to FIG.

In the sheet feeding apparatus according to the third embodiment, the first lever 3 and the first lever detection sensor 4 are provided inside the outer peripheral cylinder of the feeding roller 2 in the same manner as in the first embodiment. This is to detect whether or not there is a top sheet material, that is, whether or not the sheet material stacked on the sheet stacking plate 27 can be fed by the feeding roller 2. The second lever detection sensor 34 detects the presence or absence of a sheet material on the sheet stacking plate 27 as in the conventional sheet feeding device.

As described above, in the sheet feeding apparatus according to the third embodiment, the configuration of the first embodiment is added while utilizing the configuration of the conventional example, and the number of additional members is reduced. .

Next, with reference to FIG. 5, the threshold lines of the lever detection sensors 4 and 34, the operation of the sheet feeding device in each state of the sheet material stacked on the sheet stacking plate 27, and the like will be described. .

FIG. 5A shows each lever detection sensor 4, 34.
In this embodiment, the outer circumference of the feed roller 2 (the feed surface 2a of the feed roller 2) is described.
When the contact portion 3a of the first lever 3 contacts the tangent line H1 that is in contact with the lowermost point of the first lever 3, the ridge line 3b at the tip end opposite to the contact portion 3a is set to the threshold line A1 in the first lever detection sensor 4.
The positions of the first lever 3 and the first lever detection sensor 4 are determined so as to overlap. On the other hand, regarding the positions of the second lever 33 and the second lever detection sensor 34, when the contact portion 33a of the second lever 33 contacts the tangent H2 set below the tangent H1, the second The positional relationship is such that the ridgeline 33b of the lever 33 overlaps the threshold line A2 of the second lever detection sensor 34.

FIG. 5B is a view when a normal normal sheet material is stacked on the sheet stacking plate 27, and the uppermost sheet position is indicated by a reference line M. In this case, FIG.
As can be seen from comparison with FIG.
1 and H2, both levers 3, 3
3 both fall within the threshold lines A1 and A2. Therefore, in this case, the first lever detection sensor 4 determines that the uppermost sheet material is present in the outer peripheral cylinder of the feeding roller 2 and can be fed, and outputs a signal to that effect to the CPU. On the other hand, the second lever detection sensor 34 determines that there is a sheet material on the sheet stacking plate 27 and outputs a signal to that effect.

Next, FIG. 5C shows a state in which the sheet stacking apparatus main body 1 is mounted on the printer main body 101 when the sheet material on the sheet stacking plate 27 is exhausted or when no sheet material is stacked on the sheet stacking plate 27. FIG. When there is no sheet material on the sheet stacking plate 27, the leading ends of the levers 3, 33 enter the escape holes 27 b, 27 a of the sheet stacking plate 27, and the contact portions 3 a, 33 a are located below the sheet stacking plate 27. Ridge line 3 of each lever 3, 33
b and 33b are threshold lines A of the lever detection sensors 4 and 34, respectively.
1, Go out of A2. Therefore, in this case, the first lever detection sensor 4 determines that there is no uppermost sheet material in the outer peripheral cylinder of the feeding roller 2 and there is no sheet material that can be fed by the feeding roller 2, An error signal is output. Further, the second lever detection sensor 34 determines that there is no sheet material on the sheet stacking plate 27 and outputs an error signal in the same manner.

FIG. 5D shows a case where a sheet material whose end portion is wavy is stacked on the sheet stacking plate 27, and the sheet material cannot be fed by the feed roller 2, or It is sectional drawing shown about the case where a defect arises. In such a case, when the position of the uppermost sheet material with which the contact portion 3a of the lever 3 abuts is indicated by the reference line L, as can be understood from comparison with FIG. Since it comes to a position lower than the tangent line H1, the ridge line 3b of the first lever 3 goes out of the threshold line A1. Therefore, also in this case, it is considered that there is no uppermost sheet material in the outer peripheral cylinder of the feeding roller 2 and there is no sheet material that can be fed by the feeding roller 2, and the first lever detection sensor 4 outputs an error. Output a signal.

On the other hand, regarding the second lever 33 and the second lever detection sensor 34, since the tangent H2 is set at a position lower than the tangent H1, the second lever 33
Is included in the threshold line A2. Therefore, in this case, the second lever detection sensor 34 determines that there is a sheet material on the sheet stacking plate 27 and outputs a signal to that effect, and does not output an error signal.

As described above, in the third embodiment, the means for detecting the sheet material on the sheet stacking plate 27 is provided at two places, and when the sheet material is stacked on the sheet stacking plate 27, And the sheet stacking plate 2
No sheet material is loaded on the sheet 7 and the sheet cannot be fed, and a case where the sheet material is loaded on the sheet loading plate 27 but the sheet material does not exist in the outer peripheral cylinder of the feeding roller and the sheet cannot be fed. , Can be detected separately.

Therefore, in the sheet feeding device of the third embodiment or the image forming apparatus provided with the sheet feeding device, in addition to the effects of the first embodiment, display means such as a display is used. For example, it is only necessary to give an error display and an instruction for canceling the error to indicate that "the paper is not present and should be replenished" and "the paper is wavy and should be replaced or reinserted in the opposite direction". Therefore, there is an advantage that the user can understand the cause of the error at a glance, and it is possible to provide a sheet feeding apparatus and an image forming apparatus which are very easy to use for the user.

In the third embodiment, a feeding roller,
The first lever 3 and the first lever detection sensor 4 have the same configuration as that of the first embodiment in FIG.
In this regard, similarly to the second embodiment in FIG. 3, a lever 13 for detecting the position of the sheet material behind one feed roller 12 and a lever detection sensor 14 for detecting the position of the lever 13 may be used. Good.

In each of the embodiments described above, the lever that comes into contact with the sheet material is of a rotary type, but may be of a type other than the rotary type, for example, a vertical type.

Further, in each of the above-described embodiments, the feeding roller is formed to have a substantially half-moon-shaped cross section in which the sheet feeding failure is particularly likely to occur for the corrugated sheet material. However, the feeding roller is not limited to this. For example, it may have a circular cross section.

[0080]

As described in detail above, according to the sheet feeding apparatus of the present invention, the sheet contact member is such that the contact portion passes near the feed roller and substantially at the center in the width direction. Since the sheet material is arranged on the imaginary line in the feeding direction, it is possible to accurately detect the height position of the sheet material in the vicinity of the approximate center in the width direction of the feeding roller. It is possible to detect whether or not the sheet material can be fed by the feeding roller prior to feeding when the sheet material having the wavy shape is used.

According to the sheet feeding apparatus of the present invention,
Since the sheet contact member is arranged such that the contact portion is located in the gap between the pair of feed rollers, it is possible to accurately detect the height position of the sheet material immediately near each feed roller. This makes it possible to detect whether or not the sheet material can be fed by the feeding roller prior to feeding, for example, in the case where a sheet material with a bad end and a wavy edge is used, for example. .

Further, since it is possible to use the sheet contact member of the sheet presence / absence detecting means for detecting the presence / absence of the sheet material on the sheet stacking table, it is realized with a very simple configuration as in the conventional case. It is possible.

Therefore, according to the present invention, a sheet feeding apparatus capable of detecting whether or not a sheet material can be fed by a feeding roller such as a feeding roller prior to feeding, and an image forming apparatus having the same. The device can be provided with a simple configuration similar to the related art.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of a sheet feeding apparatus according to the present invention.

FIG. 2 is a diagram illustrating a threshold line of a lever detection sensor according to the first embodiment, an operation in each state of a sheet material stacked on a sheet stacking plate, and the like.

FIG. 3 is a diagram illustrating a second embodiment of the sheet feeding apparatus.

FIG. 4 is a diagram illustrating a third embodiment of the sheet feeding device.

FIG. 5 is a diagram illustrating a threshold line of a lever detection sensor according to the third embodiment, an operation in each state of a sheet material stacked on a sheet stacking plate, and the like.

FIG. 6 is a sectional view of a laser beam printer provided with a conventional sheet feeding device.

FIG. 7 is a diagram illustrating a conventional sheet feeding apparatus.

8A and 8B are a side view and a front view illustrating the position of a lever and the configuration of a lever detection sensor.

FIG. 9 is a diagram for explaining the operation and function of a lever and a lever detection sensor of a conventional sheet detection unit.

FIG. 10 is a diagram illustrating a conventional sheet feeding device, and is a diagram illustrating a case where a sheet material whose ends are wavy is fed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet stacking apparatus main body 2, 12 Feeding roller 2a, 12a Feeding surface 2b, 12b Standby surface 3, 13 Lever 33 Second lever 3a, 13a, 33a Contact portion 3b, 13b, 33b Edge line 4 Lever detection sensor 34 Second lever detection sensor A, A1, A2 Threshold line 5 Feed roller 7, 17, 27 Sheet stacking plate 7a, 17a, 27a, 27b Escape hole H, H1, H2 Tangent line 8 Side regulating plate 101 Printer main body

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F048 AA02 AA04 AA05 AB01 BA03 BB02 BB09 CA02 CB04 DA04 DB12 DC05 DC09 DC12 EA02 EB12 3F343 FA02 FB02 FB03 FB04 GA03 GB01 GC01 GD01 HA14 HA33 HB03 HD18 LA04 LA15 LC02 MA19 LD04 MA24 MB03 MB10 MC21 MC22 MC23

Claims (11)

[Claims] 1. A sheet loading table on which a sheet material is loaded, a feeding roller for contacting an uppermost sheet material loaded on the sheet loading table and feeding the sheet material, and on the sheet loading table A sheet contact member having a contact portion contacting the uppermost sheet material of the sheet stacker and moving up and down in accordance with the amount of the sheet material loaded on the sheet stacking table; A sheet feeding device, wherein the portion is disposed on an imaginary line in a sheet feeding direction passing through a position near the feeding roller and substantially at a center in a width direction. 2. A pair of sheet stacks on which sheet materials are stacked, and a pair of coaxially arranged sheet feeders which are arranged coaxially with each other and abut on the uppermost sheet material stacked on the sheet stacker to feed the sheet materials. A feed roller, and a sheet contact member having a contact portion that comes into contact with the uppermost sheet material on the sheet stacking table and moving up and down according to the stacking amount of the sheet material on the sheet stacking table; The sheet feeding device according to claim 1, wherein the sheet contact member is arranged such that the contact portion is located in a gap between the respective feeding rollers. 3. The sheet feeding device according to claim 1, further comprising a sensor that outputs a detection signal according to a position of the contact portion of the sheet contact member. 4. The sheet feeding apparatus according to claim 3, further comprising a sheet presence / absence detection unit that detects presence / absence of a sheet material on the sheet stacking table based on a detection signal of the sensor. 5. A sheet loading table on which a sheet material is loaded,
A sheet feeding roller for contacting the uppermost sheet material stacked on the sheet stacking table and feeding the sheet material, and a sheet presence / absence detecting unit for detecting the presence or absence of the sheet material on the sheet stacking table. In the sheet feeding device, the sheet presence / absence detecting unit has a contact portion that contacts a topmost sheet material on the sheet stacking table, and moves up and down according to a stacking amount of the sheet material on the sheet stacking table. A sheet contact member, and a sensor that outputs a detection signal corresponding to a position of the contact portion of the sheet contact member, wherein the sheet contact member has the contact portion near the feeding roller and A sheet feeding device arranged on an imaginary line in a sheet feeding direction passing through a substantially central position in a width direction. 6. A sheet stacking table on which a sheet material is stacked, and a pair of coaxially arranged sheet sheets which are arranged coaxially with each other and contact the uppermost sheet material stacked on the sheet stacking table to feed the sheet material. A feed roller; and a sheet presence / absence detection unit that detects presence / absence of a sheet material on the sheet stacking table, wherein the sheet presence / absence detection unit is configured to be in contact with an uppermost sheet material on the sheet stacking table. A sheet contact member that moves up and down according to the amount of sheet material loaded on the sheet stacking table, and a sensor that outputs a detection signal according to the position of the contact portion of the sheet contact member. The sheet feeding device, wherein the sheet contact member is disposed such that the contact portion is located in a gap between the respective feeding rollers. 7. The sensor according to claim 1, wherein the contact portion of the sheet contact member contacts the sheet material of the feed roller based on a deformation of the sheet material loaded on the sheet loading table, and the sheet material is removed. The sheet feeding apparatus according to claim 3, wherein an error signal is output when the sheet is located at a position relatively lower than a part to be fed. 8. The sheet feeding device according to claim 7, further comprising an error display unit for displaying an error indicating that feeding is impossible based on an error signal from the sensor. 9. A driving control unit for controlling driving of the feeding roller, wherein the driving control unit is configured to prohibit feeding of the sheet material when the error signal is output from the sensor. 9. The sheet feeding device according to claim 7, wherein driving of the feeding roller is controlled. 10. The sheet feeding device according to claim 1, wherein the sheet stacking table includes a hole into which the contact portion of the sheet contact member enters. . 11. A sheet feeding device according to claim 1, further comprising: an image forming unit that forms an image on a sheet material fed by the sheet feeding device. Characteristic image forming apparatus.