JP2803671B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer, and more particularly, to an image forming apparatus in which a large number of sheets are housed in a machine and orthogonal to a sheet conveying direction. The present invention relates to an image forming apparatus (hereinafter, referred to as a copying machine) including a sheet storage device (hereinafter, referred to as a cassette) which is detachably mounted in a direction in which the image forming apparatus is mounted.

2. Description of the Related Art Conventionally, a copier including a cassette that accommodates a large number of sheets and is removably mounted in a direction perpendicular to the sheet conveying direction is known in the interior of the apparatus. When a cassette is installed in the apparatus, a sheet presence / absence sensor detects the presence / absence of a sheet stored in the cassette.

However, in the copying machine, when the cassette is attached or detached, the sensor lever of the sensor for detecting the presence or absence of a sheet stored in the cassette may come into contact with the cassette, which may damage the sensor arm.

In order to solve this drawback, the present applicant has devised a copying machine provided with a sensor whose sensor arm moves up and down when a cassette is attached and detached. The copying machine 10 has a cassette 1 detachably mounted on a machine body 11 as shown in FIGS. 14 to 17 (not shown).
It can be pulled out to the front side of 11. Also, the fuselage
A pressure plate 13 is supported on the upper part of the opening 11 so as to be freely opened and closed.
A handle 44 is provided on the front side of the cassette 1, and a handle 45 for lifting the cassette 1 is provided on the left and right sides of the cassette 1. The cassette 1 has a middle plate 2 on which a large number of sheets S are stacked, and a regulating plate 3 for regulating the lateral movement of the sheets S. The middle plate 2 has a plurality of long holes 4, 4 formed in the sheet width direction, and the regulating plate 3 is configured to be able to move to these long holes 4, 4 according to the sheet size. And project from the long hole 4.
A separating claw 5 for separating the sheets S one by one is provided above the downstream end of the regulating plate 3.
A separation claw 5 is also provided on the right side of the upper side of the downstream side of the side plate 8. A shaft 6 connected to a motor (not shown) is rotatably supported on the upper part of the cassette 2.
A plurality of paper feed rollers 7 are fixed to the shaft 6 so as to correspond to various sheet sizes. The middle plate 2 is urged upward by a spring 9, and the sheets S loaded on the middle plate 2 are urged toward the sheet feeding rollers 7.

A light transmission type sheet presence / absence sensor 67 is attached to the upper body 11 of the cassette 1 via a mounting plate 66, and a shaft 69 is supported by a body frame (not shown) facing the sensor 67. . Further, at the shaft 69, one end 70a
A wide and L-shaped sensor lever 70 in side view is swingably supported, and a detection roller 71 is rotatably supported at the other end of the lever 70 in the cassette 1 attaching / detaching direction. Also,
A receiving member 68 is provided on the back side of the portion where the depressions 35 are located, and the receiving member 68 transmits the urging force of the spring 9 to the middle plate 2 uniformly. Further, the spring 9 is adapted to move along with the regulating plate 3.

When the cassette 1 is mounted, the detection roller 71 is moved from the position indicated by the solid line by the sheet S stored in the cassette 1.
The sensor 67 is turned off by moving to the position indicated by the dashed line (see FIG. 17) and blocking one end 70a of the sensor lever 70 between the light emitting portion and the light receiving portion of the sheet presence sensor 67. Then, the control unit that receives the OFF signal of the sensor 67 determines that there is a sheet S in the cassette 1. Then, when the start key is pressed, the sheet S is fed from the cassette 1 by the paper feed roller 7, the image of the sheet S is copied, and the sheet S is discharged out of the machine body 11. By the same operation, the copying operation is repeated, and when the sheet S runs out in the cassette 1, the detection roller 71
Falls into the hole 48 formed in the middle plate 2 and moves from the two-dot chain line position to the solid line position. As a result, the one end 70a of the sensor lever 70 also moves from the two-dot chain line position that blocks between the light emitting unit and the light receiving unit of the sheet presence sensor 67 to the actual battle position that does not block between them, and the sensor 67 turns ON. Further, the sensor
The control unit that receives the ON signal of 67 determines that there is no sheet S in the cassette 1 and issues an alarm to the display unit. Then, the operator confirming the alarm pulls out the cassette 1, stacks the sheets S on the cassette 1, and mounts the sheets S on the body 11.

(C) Problems to be Solved by the Invention In the above-described copying machine, the detection roller 71 rotates only in the cassette attaching / detaching direction. There was a problem that a paper defect might occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which does not cause conveyance resistance during sheet feeding, thereby solving the above-mentioned problems.

(D) Means for Solving the Problems The present invention has been made in view of the above circumstances, and has a structure in which a large number of sheets are stored in a body and detachably mounted in a direction orthogonal to a sheet conveying direction. A sheet storage device, rotatable in the sheet conveying direction so as to be able to move between a detection position for detecting a sheet stored in the sheet storage device and a retracted position separated from the sheet, which is disposed in the body. A movable sheet detecting movable body, and a sensor operated by the movable sheet detecting movable body, and a detecting unit configured to detect the presence or absence of a sheet stored in the sheet storing apparatus. An urging means disposed on the body, having an engaging portion, and urging the sheet detection movable body toward the retreat position side in cooperation with the sheet detection movable body; and mounting the sheet storage device. A release unit that is disposed on the front side and that comes into contact with the engagement unit to release the urging force of the urging means in response to mounting the sheet storage device on the body; and a mounting direction of the sheet storage device. A positioning unit disposed on the front side, which abuts on positioning means disposed on the body when the sheet storage device is mounted on the body to determine a sheet feeding position of the sheet storage device. .

(E) Operation Based on the above configuration, when the sheet storage device is mounted in the body, the release portion of the sheet storage device comes into contact with the engagement portion to release the urging force of the urging means, and the sheet detection movable body is moved. Move to the detection position. Then, the sheet storage device is positioned and held at the sheet feeding position by the positioning portion of the sheet storage device coming into contact with the positioning means.

At this time, since the release unit and the positioning unit are both disposed on the near side in the mounting direction of the sheet storage device, the urging release operation by the release unit and the positioning operation to the sheet feeding position by the positioning unit are performed. Is performed at an accurate timing without causing a displacement.

Then, in a state where the sheet storage device is mounted at the sheet feeding position, the sheet detecting movable body is at the detection position by detecting the urging of the urging means, and the presence or absence of the sheet of the sheet storage device is detected. The sheet detection movable body rotates in the sheet conveying direction to allow the sheet to be smoothly fed.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

The cassette 1 is, as shown in FIG.
It is removably mounted in 11 and is guided by guides 12 and 12 so that it can be pulled out in a direction perpendicular to the sheet conveying direction. The fuselage 11 includes a pressure plate 13, a platen 15, a light source 16, mirrors 17, 18, 19, 20, 21, 22, and a lens 23. A transport roller pair 25 and a register roller are provided downstream of the cassette 1. A pair 26 is provided. Further, an image forming section 27 is provided downstream of the roller pair 26, and a transport belt 29 and a fixing device 30 are provided downstream of the image forming section 27. A discharge roller pair 31 is provided downstream of the fixing device 30, and a discharge tray 32 is provided downstream of the discharge roller pair 31.

As shown in FIGS. 3, 4, and 5 (a) and (b), the cassette 1 has a sheet size detection block 33 detachably mounted on the back side in the cassette insertion direction C. The block 33 is configured to press a sheet size detection switch 63a, 63b, 63c disposed on the side of the body 11 described below, and the block 33 can be replaced according to the sheet size. It has become. Furthermore, middle plate 2
The third and subsequent feed rollers 7a, 7b from the right in the feed direction
A recess 35 is formed as a relief portion at a position opposing the sheet feeding rollers 7a and 7b when feeding a narrow sheet S not located at these rollers 7a and 7b.
b does not contact the middle plate 2. In addition, 3 in the figure
Reference numeral 6 denotes a regulating plate that regulates the backward movement of the sheet S. The regulating plate 36 controls the holes 40 corresponding to the sheet size in the main body of the cassette 1 and the backward movement of the vertically long sheet S. It can be moved and attached to the regulating holes 41. A concave portion 42 as a first engaging portion is formed in the upper portion on the far side of the cassette 1, and a plurality of cassettes 1 are stacked on the lower portion on the far side of the cassette 1. A projection 43 is provided as a second engagement portion that fits into the recess 42 of the lower cassette 1 to position the cassette 1. A stopper 46 made of resin is provided at both ends on the far side of the cassette 1.
Is composed of a stopper receiving portion 47, a step portion 49, a slope 50, and a spring portion 51 (see FIG. 6). Also, the stopper
Reference numeral 46 denotes a protrusion amount and an elastic limit that are set so that when the cassette 1 is mounted on the body 11, it is elastically deformed and becomes flush with the upper surface of the cassette 1.

Reference numeral 48 in FIG. 4 denotes a hole for detecting the presence or absence of a sheet. As shown in FIGS. 1A and 1B, a shaft 80 is supported substantially horizontally near the paper feed roller 7, and the sensor arm 81 is swingable by the shaft 80. Supported. A sheet presence sensor 85 is provided on a guide plate 83 which is located near one end 81a of the arm 81 and forms an upper part of the paper feed path 82, and the sensor 85 is turned on by one end 81a of the sensor arm 81.・ It is turned off. Further, the paper feed path 82 is constituted by a guide plate 83 and a guide block 86 provided opposite to the guide plate 83, and the tip of the block 86 has a rib shape. A shaft 87 is supported on the front side of the block 86, and a release lever (biasing means) 89 is swingably supported by the shaft 87. The release lever 89 is urged to swing counterclockwise by a coil spring (biasing means) 90, and one end 89a of the release lever 89 is extended horizontally to the sensor arm (sheet detection movable body) 81. The arm 81 comes into contact with the distal end 81b of the bent portion to urge the arm 81 to swing clockwise. The sheet presence sensor 85 is connected to a control unit 91. In a state where the cassette is not mounted, the arm 81 is at the position indicated by the broken line in FIG.
The sensor 85 is off.

Also, on the upper part of the fuselage 11 where the cassette 1 is mounted,
As shown in FIG. 7A, a groove into which the stopper 46 fits.
51, a step 52 with which the stopper 46 is engaged, and a step 52
A front inclined surface 53 is formed.

Further, as shown in FIG. 8, a positioning plate (positioning portion) 55 formed of a steel plate is fixed to a near center of the cassette 1 by screws or the like.
Is attached to a magnet catch (positioning means) 57 provided on the machine body 11 via a mounting plate 56. Then, the mounting plate 56 is attached to the body 11 in the direction of the arrow.
mm so that the position of the magnet catch 57 can be adjusted.
In addition, as shown in FIG. 8 and FIG.
55 is provided at a position on the near side in the mounting direction of the cassette 1 similarly to a part (release section) 1a of the cassette 1 described later.

Also, in the portion of the body 11 facing the block 33,
As shown in FIGS. 9 (a) and 9 (b), a mounting plate 59 is provided, and the mounting plate 59 is a pin having a protruded tip protruding from a bracket 60 fixed to the body 11. The pin 61 is slidably supported, and a spring 62 is contracted between the tip of the pin 61 and the mounting plate 59. The mounting plate 59 further includes a switch 63a for detecting a sheet size based on the position of the block 33,
63b, 63c and a switch 63d for detecting the presence / absence of the cassette 1 are provided, and the cassette 1 has a gap between the mounting plate 59 and the main body of the cassette 1 at a position sandwiching these switches 63a. A positioning projection 65 for positioning is provided.

When the sheet S is positioned up to the paper feed rollers 7a and 7b, as shown in FIGS. 10 and 11, a sheet made of a flexible material forming the same plane as the middle plate 2 is used. The plate auxiliary member 37 is configured so as to be able to be mounted in the recess 35, whereby the pressing force of the sheet S against the sheet feeding rollers 7a and 7b is ensured.

And, as shown in detail in FIG. 12, the intermediate plate auxiliary member 37 has claws 37a at both ends, and the claws 37a, 37a are inserted into slit-shaped holes 35a, 35a formed in the recess 35. It is designed to be supported by being inserted.

Further, as shown in detail in FIGS. 13 (a) and 13 (b), the separation claw 5 has a U-shape in a front view, and one end 5a thereof is turned by a shaft 72 supported by the cassette 1 body. It is movably supported. A link lever 73 is provided below the separation claw 5.
Is pivotally supported by a shaft 75 supported by the cassette main body, and one end 73a of the lever 73 abuts on the middle plate 2 on which the sheet S is loaded and swings clockwise to thereby rotate the other end 73b. Urges the separation claw 5 to rotate counterclockwise.

Since the present embodiment has the above configuration, the copying machine 10
When a plurality of cassettes 11 are stacked outside the body 11, the operator fits the lower projection 43 of the upper cassette 1 into the upper concave portion 42 of the lower cassette 1. Thereby, a plurality of cassettes 1 can be stacked without the lower surface of the upper cassette 1 coming into contact with the upper surface of the lower cassette 1 (see FIGS. 5A and 5B).

When the largest size sheet S is stored in one of the stacked cassettes 1 and is mounted on the copying machine 10, the operator moves the regulating plate 3 to the left end of the cassette and feeds the sheet. The middle plate auxiliary member 37 is mounted in the depressions 35, 35 at positions opposed to the paper rollers 7a, 7b.
When a large number of maximum size sheets S (for example, width D) are stacked on the middle plate 2 of the cassette 1 (see FIG. 10),
The middle plate 2 descends against the spring 9 due to the weight of the sheet S. Further, when sheets S are stacked until the sheets are fully loaded, the operator loads sheets S...
These sheets S are pressed against the spring 9 in the direction of arrow F (see FIG. 13 (b)). The middle plate 2 is also pushed down in the F direction together with these sheets S, and the middle plate 2 comes into contact with one end 73a of the link lever 73 to swing the lever 73 clockwise. Then, when the lever 73 swings clockwise, the other end 73b of the lever 73 comes into contact with the separation claw 5 and rotates the separation claw 5 in a counterclockwise direction. From the position to the solid line position (see FIG. 13 (b)), and the leading end thereof is pushed up from the uppermost surface of the sheets S. Further, the operator moves the sheets S... In the transport direction until the leading ends of the sheets S.
When the force in the direction is released, the middle plate 2 and the sheets 2.
, The uppermost sheet S of the sheets S...
Abuts on the tip of the separation claw 5 and is positioned. On this occasion,
The urging force of the spring 9 in the portion where the recess 35 is located is the receiving member 68
Thus, the power is uniformly transmitted to the middle plate 2. Further, at this time, one end 73a of the link lever 73 and the middle plate 2 are not in contact with each other, and the other end 73b is not in contact with the separation claw 5, so that the link lever 73 is in contact with the middle plate 2 and the separation claw. It has no effect.

When the cassette 1 loaded with the sheets S... Is mounted on the body 11, the operator
When the cassette is placed on 12, 12 and pushed in the direction of arrow G (see FIG. 7 (a)), the upper surface of the stopper 46 is pushed downward by the inclined surface 53 on the side of the machine body 11, so that the upper surface of the stopper 46 is deformed and the cassette is deformed. 1 and the same plane. Then, when the stopper 46 exceeds the step 52, the deformation of the stopper 46 returns to its original state,
The stopper 46 and the step 52 are engaged with each other and the step 49
Abuts on the cassette body to prevent deformation,
Cannot be easily pulled out in the direction of arrow H (see FIG. 7 (b)). If the cassette 1 needs to be pulled out, the cassette 1 is rotated in the direction of arrow I (see FIG. 7 (c)) so that the lower end of the cassette 1 is located at the escape of the rail 12, and When the upper part of the cassette 1 becomes lower than the step 52 of the machine body 11, the cassette 1 is pulled out in the direction of arrow J.

Further, when the cassette 1 is pushed into the body 11, the positioning plate
55 is attracted to the magnet catch 57, whereby the cassette 1 is positioned (see FIG. 8). At this time, the positioning projections 65, 65 on the back side of the cassette 1 abut against the mounting plate 59, and the mounting plate 59 is moved against the springs 62, 62 so that the switch 6
3a: The distance between the leading end and the cassette 1 body is set to a predetermined amount. Then, the block 33 is a switch 63a for detecting the sheet size,
One of 63b, 63c, for example, 63b is turned on, and the cassette 1 body turns on a switch 63d for detecting the presence or absence of the cassette.
The ON signals of these switches 63b and 63d are transmitted to the control unit.

Also, by mounting the cassette 1, a part 1a of the cassette 1
Abuts on one end 89b of the release lever 89 to move the lever 89 clockwise, and the lever 89 swings from the solid line position to the chain line position (see FIG. 1 (b)). Then, the sensor arm 81 urged clockwise by one end 89a of the lever 89
Swings by its own weight in the counterclockwise direction, moves from the chain line position to the solid line position (FIG. 1 (a)), and moves one end 81c of the arm 81.
Abuts on the uppermost sheet S (see FIG. 1A).
Note that the operation of the part 1a of the cassette 1 swinging the release lever 89 is such that the part 1a of the cassette 1 is located at a position on the near side in the mounting direction of the cassette 1 similar to the positioning plate 55 (see FIG. 8). In addition, since the displacement of the contact position between the part 1a of the cassette 1 and the release lever 89 can be prevented, it is performed very accurately. It is more preferable that the one end 81c of the sensor arm 81 abuts on the sheet S, if the timing is set immediately before the cassette is mounted, in order to prevent the sheet from shifting. At this time, since one end 81a of the sensor arm 81 still blocks the light emitting portion and the light receiving portion of the sheet presence / absence sensor 85, the sensor 85 remains OFF. Then, the control unit 91 that receives the OFF signal from the sensor 85 determines that there is a sheet S in the cassette 1.
When a document is placed on the platen 15 and the start key is pressed, the lamp 16, the mirrors 17, 18, 19, 20, 21, 22 and the lens 2
The image of the original is read by 3 to form an image on the image forming unit 27. On the other hand, the sheet S is separated from the cassette 1 by the sheet feeding roller 7 and the separation claws 5, 5, and only the uppermost sheet S is fed. At this time, the sensor arm 81 is swingable in the sheet conveying direction (leftward or rightward in FIG. 1A).
Therefore, there is no transfer resistance. Then, the sheet S is conveyed to the registration roller pair 26 by the conveyance roller pair 25, and the conveyance force is applied by the conveyance roller pair 25 that abuts the nip of the roller pair 26 and slips, thereby correcting the skew. Then, the sheet is conveyed in synchronization with the image of the image forming unit 27 by the registration roller pair 26 which starts rotating at a predetermined timing. Further, the image of the sheet S is copied by the image forming unit 27, and is conveyed to the fixing device 30 by the conveyance belt 29. Then, the sheet S is fixed with an image by the fixing device 30, and is discharged to a discharge tray 32 by a pair of discharge rollers 31.

When stacking sheets S of a medium size (for example, width E) on the cassette 1, the operator moves the regulating plate 3 according to the sheet width, and adds the medium plate auxiliary only to the recess 35 opposed to the sheet feeding roller 7b. The member 37 is mounted, and the member 37 opposing the paper feed roller 16a is removed (see FIG. 10). Hereinafter, an image forming operation is performed by the same operation as described above.

Then, when the sheet S runs out in the cassette 1, one end 81c of the sensor arm 81 falls into the hole 48, and the sensor arm 81 swings counterclockwise. As a result, the other end 81a of the sensor arm 81 moves from a position blocking the light emitting portion and the light receiving portion of the sheet presence / absence sensor 85 to a position not blocking the gap therebetween, and the sensor 85 is turned ON (FIG. 1 (c)). )reference). Furthermore,
The control section 91 which receives the ON signal of the sensor 85 determines that there is no sheet S in the cassette 1 and issues an alarm on the display section. Then, the operator who confirms the alarm pulls out the cassette 1 and replenishes the cassette 1 with sheets S. When pulling out the cassette 1, a part of the cassette 1
When 1a is separated from one end of the release lever 89, the lever 89 swings counterclockwise by the urging force of the coil spring 90, and the sensor arm 81 is pushed clockwise by the lever 89 pushing the tip 81b. Through the hole 48, then gradually the first
It retreats to the position shown by the solid line in FIG. Thus, the sensor arm 81 does not contact the cassette 1.

As described above, in the present embodiment, the positioning portion 55 between the cassette 1 and the body 11 is provided on the near side in the mounting direction (see FIG. 8).
The release portion (part of the cassette 1) 1a is also provided on the near side in the mounting direction similarly to the positioning portion (positioning plate) 55 (see FIG. 1B, urging means (release lever 89, coil spring 90) Can be reliably performed.
If the contact position between the release lever 89 and the cassette 1 is displaced (causing variations in dimensional accuracy of the product or expansion of the product due to temperature change, etc.), the urging means cannot be released sufficiently, and a sheet detection error may occur. Although there is a possibility of causing this, as in this embodiment,
By setting the contact position of the release lever 89 and the portion 1a of the cassette 1 at the same position as the positioning portion 55 between the cassette 1 and the body 11, the occurrence of displacement can be largely prevented, and It is possible to effectively prevent a failure in releasing the means.

The device according to the invention is as described above, but is not limited to this embodiment. For example, one end 81c of the sensor 81 may be a rotatable roller. The rotation axis of the roller is parallel to the axis of the roller 7.

(G) Effects of the Invention As described above, according to the present invention, when the sheet storage device is not mounted in the body, the sheet detecting movable body is in the retracted position by the urging means, and the sensor is not operated. , The durability of the sensor is not impaired.

In addition, since the sheet detection movable body rotates in the sheet conveying direction to allow the sheet to move smoothly, it is possible to effectively prevent skew and defective feeding during sheet feeding,
When the sheet storage device is attached to and detached from the body, the sheet detection movable body is moved to the retracted position, so that the sheet detection movable body does not interfere with the attachment / detachment operation of the sheet storage device.

Further, since the urging release operation and the positioning operation are performed at an accurate timing by the release unit and the positioning unit located in the same mounting direction of the sheet storage device, the release operation and the positioning operation are performed accurately in the vicinity of the sheet feeding position of the sheet storage device. When the force is released, the movable sheet detecting member comes to the detecting position, and the movable member comes to the detecting position on the front side of the sheet feeding position. Can be prevented, and when the positioning section is at the sheet feeding position in contact with the positioning means, the release means releases the urging means without fail,
It is possible to prevent the free rotation of the sheet detection movable body from being hindered by the release failure, and to reliably detect the presence or absence of the sheet in the sheet storage device.

[Brief description of the drawings]

1 (a), 1 (b) and 1 (c) are views showing a main part of an image forming apparatus according to the present invention. FIG. 2 is a front sectional view showing the image forming apparatus according to the present invention. Further, FIGS. 3 to 13 (a) and 13 (b) are views showing the main parts of the image forming apparatus according to the present invention. 14 to 17 show an image forming apparatus devised by the present applicant. DESCRIPTION OF SYMBOLS 1 ... Sheet storage apparatus, 10 ... Image forming apparatus, 11 ... Machine body, 55 ... Positioning part (positioning plate), 57 ... Positioning means (magnet catch), 81 ... Sheet detection movable body (sensor arm) , 85 ... sensor (sheet presence sensor), 89 ... urging means (release lever), 89b ... engaging part (one end), 90 ... urging means (coil spring), S ... sheet.

Claims (1)

(57) [Claims] A sheet storage device for storing a large number of sheets in a body and detachably mounted in a direction orthogonal to a sheet conveying direction; a sheet disposed in the body and stored in the sheet storage device. A sheet detection movable body rotatable in the sheet conveying direction so as to be able to move between a detection position for detecting the sheet detection position and a retracted position separated from the sheet, and a sensor operated by the sheet detection movable body. Detecting means for detecting the presence / absence of a sheet stored in the sheet storage device. The image forming apparatus further comprising: an engagement portion disposed on the body and linked to the sheet detection movable body. Biasing means for biasing the sheet detection movable body to the retracted position side, and disposed in front of the mounting direction of the sheet storage device, and in accordance with mounting the sheet storage device on the body, A release unit that comes into contact with the engagement unit to release the urging force of the urging unit; and a release unit that is disposed on the front side in the mounting direction of the sheet storage device, and is disposed on the body when the sheet storage device is mounted on the body. And a positioning unit for determining a sheet feeding position of the sheet storage device by contacting the positioning means.