JPH10198144A - Image forming device and developer cartridge therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device and a developer cartridge therefor capable of securing the sufficient recovery amount of developer without decreasing the filling amount of unused developer by increasing substantial effective capacity while preventing a developer recovery box from getting large. SOLUTION: Since a developer recovery port 146 is positioned on the upper side (anti-gravity side) within an end face 84 in the recovery box 132b, the free end of a plate-like elastic body 143 is separated from the port 146 by the gravity F of a weight 142. Therefore, the developer L discharged from a developing device 12 is recovered from the port 146 into the recovery box. Meanwhile, the developer recovery port 146 is positioned on the lower side (gravity side) within the end face 84 in the recovery box 132a, so that the free end of the plate-like elastic body 143 is pressed to the port 146 by the gravity F of the weight 142 so as to prevent the back flow of the developer L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine or a facsimile apparatus for forming a toner image on a recording sheet, and a developer cartridge thereof. The present invention relates to an image forming apparatus provided with a function of collecting a developer in a developer cartridge and the developer cartridge.

[0002]

2. Description of the Related Art An electrophotographic full-color image forming apparatus is equipped with three developing devices each filled with a developer of three primary colors, or four developing devices further filled with a black developer. Then, these are arranged to face one or a plurality of photosensitive drums, and an electrostatic latent image is visualized with a plurality of colors of developer and superimposed to form an image.

In general, when importance is attached to downsizing and cost reduction of an apparatus, a configuration is adopted in which a plurality of developing units are sequentially arranged facing one photosensitive drum. For this reason, a rotating body holding four developing units is arranged near one photosensitive drum, and by rotating the rotating body, each developing unit is sequentially moved to a position facing the photosensitive drum, and each developing unit is moved. An image forming apparatus that sequentially visualizes an electrostatic latent image with an agent has been proposed.

In such an image forming apparatus, a two-component developer containing a toner and a carrier is used as a developer. However, in a two-component developer, the carrier deteriorates when image formation is repeated and the chargeability is deteriorated. Therefore, it is necessary to replace the carrier by replenishing new developer and recovering excess developer at the same time. For this reason, for example,
In Japanese Patent No. 591 or JP-A-5-289504, a small amount of carrier is replenished together with the toner necessary for image formation, and the naturally increased developer gradually overflows from the developing device, thereby replenishing the toner and replacing the carrier. And a trickle developing method have been proposed. At this time, the excess developer is collected from the developing device by a developer collecting port provided in each of the developer cartridge and the developing device so as to face each other when the developer cartridge is properly mounted on the developing device. And via a developer outlet.

[0005]

FIG. 11 is a cross-sectional view of a cylindrical developer collection box 300 mounted on a conventional developer cartridge, and is similar to one embodiment of the present invention described later with reference to FIG. Is attached to one end of a cylindrical developer cartridge. The collection box 300 includes a cylindrical side surface 203 extending in the longitudinal direction of the developer cartridge,
An end face 202 orthogonal to the long axis is formed, and a cap 131 is fitted to the opposite end of the end face 202. At the center of the end surface 202 of the collecting box 132, a developer collecting port 201 for collecting excess developer from the developing device is opened.

However, in the above-described configuration, when the collected developer L accumulates in the collection box 300 for about half or more, it flows backward from the collection port 201 to the developing device, so that only less than half the volume of the collection box 300 is collected. Can not. On the other hand, if the size of the collection box 300 is increased so that a sufficient amount of the developer can be collected even if the effective volume of the collection box 300 is half, the volume of the developer container is reduced by that much, and the unused developer is not used. There is a problem that the life (replacement cycle) of the developer cartridge is shortened because the amount of the filled developer decreases.

An object of the present invention is to solve the above-mentioned problems of the prior art and reduce the amount of unused developer by increasing the effective volume of the collection box without increasing the size of the collection box. An object of the present invention is to provide an image forming apparatus and a developer cartridge for the same, which can ensure a sufficient collection amount without any trouble.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention is characterized in that the following means are taken. (1) In a cylindrical developer cartridge in which a developer collection box is mounted at one end of a cylindrical developer accommodating section for accommodating a developer containing at least a toner and a carrier, a developer collection port opened to the collection box. Has a shutter mechanism for preventing the collected developer from flowing out. According to such a configuration, it is possible to prevent the developer collected in the collection box from flowing back to the developing device side. (2) the collection port is opened near an end of an end face intersecting with the long axis of the developer cartridge, and the shutter mechanism is
When the collection box is rotated about the axis, the collection port is opened within a predetermined range within one rotation and closed outside the predetermined range. According to such a configuration,
The shutter mechanism provided at the collection port automatically opens and closes according to the position of the collection box, so that it closes when the developer flows backward to the developer unit, and opens when it is not. In this case, the developer can be collected without flowing backward. (3) The end face of the collection box is inclined by a predetermined angle with respect to a plane orthogonal to the long axis, the collection port is opened at an obtuse angle with the side surface of the collection box, and the shutter mechanism is cantilevered. It is composed of a long plate-like elastic body which is supported in the form of a beam and whose weight is fixed to the free end, and fixing means for fixing the plate-like elastic body to the collection box, and the gravity caused by the weight of the plate-like elastic body When the collection box is out of the predetermined range, the free end of the collection box is pressed against the collection port, and when the collection box is within the predetermined range, the collection box is separated from the collection port. According to such a configuration, the shutter mechanism opens when the developer collection port is above the center position of the end face, and closes when the developer collection port is below the center position, without increasing the size of the collection box. Only its effective volume can be increased. (4) The fixing means further includes means for restricting the movement of the plate-like elastic body so that one end of the elastic body is not separated from the recovery port by a predetermined distance or more. According to such a configuration, set of the plate-like elastic body can be prevented. (5) A slit was formed in the longitudinal direction of the plate-like elastic body. According to such a configuration, when the plate-like elastic body is pressed against the recovery port, the developer that has entered between the end face and the end face can be easily moved to the opposite side through the slit, so that the plate-like elastic body The movement is not hindered by the developer. (6) a developing device in which the developer cartridge of any one of the constitutions (1) to (5) is detachably mounted, a rotating body that rotates while holding a plurality of developing devices concentrically around a rotation axis, Control means for controlling the rotation of the rotator so that each developing device is sequentially arranged to face the rotating drum, and excessive developer in the developing device is transferred to the collection box of the developer cartridge by rotation of the rotator. In the image forming apparatus to be recovered, the developer cartridge is mounted on the developing device such that the recovery port of the recovery box is positioned on the rotation shaft side in the end face. According to such a configuration, it is possible to provide an image forming apparatus in which a large number of carriers can be replaced by a single cartridge replacement.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view of a developing device 12 and a developer cartridge 10 of a rotary developing device to which the present invention is applied. FIG. 2 is a cross-sectional view showing a state in which the developing device 12 and the developer cartridge 10 are attached to the rotary developing device. FIG. 3 is a sectional view showing a state where the developer cartridge 10 is assembled to the developing device 12. FIG. 4 is an enlarged sectional view of the developing device 12 and the developer cartridge 10. FIG. 5 is an exploded perspective view of the developer cartridge 10. FIG. 6 is an enlarged perspective view of the developing device 12. FIG.
5 is an enlarged perspective view of a long lid 38 of the developing device 12. FIG. FIG.
3 is an enlarged perspective view of the developer cartridge 10. FIG.

As shown in FIG. 2, the rotary developing device includes a photosensitive drum 20, and a substantially cross-shaped rotating body 34 is arranged beside the photosensitive drum 20. In the developing device 12 and the developer cartridge 10, C (cyan), M (magenta), Y (yellow), and BK (black) developers L in which toner and carrier are premixed
Is housed.

As shown in FIG. 1, the developing device 12 includes a long case 14 having an open upper portion, and the inside thereof is filled with a developer L obtained by premixing a toner and a carrier. . A magnet roll 18 is rotatably supported on the lateral side wall 16 of the case 14, and is rotated in the direction of arrow A by a gear mechanism (not shown) provided on the shaft 17. The magnet roll 18
The carrier contained in the developer is attracted by magnetic force to form a magnetic brush, and the toner adsorbed on the carrier is supplied to the photosensitive drum 20. Thereby, the electrostatic latent image formed on the photosensitive drum 20 is visualized. In addition, two spiral augers 22 are arranged in parallel with the magnet roll 18,
24 is pivotally supported on the side wall 16. Gear mechanisms (not shown) are provided at the ends of the shafts 26, 28 of the spiral augers 22, 24, and rotate in the same direction as the magnet roll 18.

As shown in FIGS. 3 and 6, the shaft 2
The spiral portion 30 provided on the outer periphery of the shaft 6 has a spiral shape inclined in the direction of arrow B, and the spiral portion 32 provided on the outer periphery of the shaft 28 has a spiral shape inclined in the direction opposite to the arrow B. It has become. Thus, when the magnet roll 18 rotates, the spiral auger 22 is rotated.
Is stirred while transporting the developer L in the direction of arrow B.
The spiral auger 24 agitates while transporting the developer L in the direction opposite to the arrow B, so that the magnet roll 18
Is supplied with the developer L. When the spiral augers 22 and 24 are stopped, the spiral portions 30 and 32 are inclined in a direction in which the developer L circulates from the spiral auger 22 to the spiral auger 24 by rotation of a rotating body 34 described later.

A partition plate 36 is provided in the case 14 so as to partition the spiral augers 22 and 24 in the longitudinal direction. Both ends in the longitudinal direction of the partition plate 36 do not reach the side wall 16. Near the right end, the developer L stirred and conveyed by the spiral auger 22 is conveyed to the spiral auger 24 side, and near the left end. The developer L stirred and transported by the spiral auger 24 is transported to the spiral auger 22 side.
Further, the spiral auger 22 is provided with a spiral portion that is wound in the reverse direction of the spiral portion 30 near the right end portion of the partition plate 36, and the spiral auger 24 has a spiral portion 32 near the left end portion of the partition plate 36. The spiral part of the reverse winding is provided. Thereby, the partition plate 36
The developer L can smoothly circulate between the spiral auger 22 and the spiral auger 24 from the boundary.

On the other hand, a packing 37 is adhered to the opening edge of the case 14 and is sealed by a long lid 38. The long lid 38 has a flange 40 protruding therefrom.
The outer peripheral portion of the magnet roll 18 is held between the flange 42 formed on the case 14 and a part thereof exposed. The long lid 38 is provided with a claw (not shown) protruding therefrom, and is engaged with a concave portion 44 formed in the case 14 to temporarily fix the long lid 38 to the case 14.

A rectangular supply port 41 (see FIG. 3) penetrates to the left from the center of the long lid 38. Supply port 41
A mounting plate 52 is erected on the front side of the mounting plate 52. The side surface of the mounting plate 52 is curved in an arc shape, and a substantially cylindrical casing 54 is mounted on this arc surface. As shown in FIG. 3, an opening 56 communicating with the supply port 41 is formed on the outer peripheral surface of the casing 54. Also,
A flap (not shown) that opens and closes the supply port 41 according to the rotational position of the rotating body 34 (change in the direction of action of gravity) described later is provided on the periphery of the supply port 41. A spiral auger 60 is provided in the casing 54. Spiral part 62 of this spiral auger 60
Is a spiral auger 22 disposed in the case 14.
And functions to transport the developer L in the direction of arrow B. Further, guide grooves 67 are formed on both sides of the outer peripheral surface on the left side of the casing 54, and a receiving plate 66 curved so as to draw a semicircle is attached. The receiving plate 66 is provided with a receiving port 64. An arc-shaped curved receiving plate 76 is provided on an extension of the receiving plate 66.
Through the discharge pipe 70.

The discharge pipe 70 is twisted and bent in a "L" shape, and the recovery port 72 located in the case 14 is located upstream of the supply port 41 (in the direction in which the developer is conveyed by the spiral auger 22). ). Further, the collection port 72 is formed by the magnet roll 18 and the photosensitive drum 20.
Is set so as to be parallel with the developer surface of the developer, and the opening area thereof is the carrier contained in the developer consumed at one image density of 100% of the maximum print paper. Of the rotating body 34 can be recovered by one rotation.

On the other hand, a slide shutter 68 curved so as to draw a circular shape is slidably engaged with the guide groove 67 of the receiving plate 66. A stop wall 69 (see FIG. 7) is formed at the upper end of the slide shutter 68. When the end of the receiving plate 66 hits the stop wall 69, the slide shutter 68 stops at a position where the receiving port 64 and the discharge port 74 are shielded. In the width direction of the stop wall 69, an engagement groove 78 that engages with an engagement piece 122 protruding from the collection case 120 shown in FIG. 5 when the developer cartridge 10 is mounted is cut. .

Further, a cylindrical holder 124 having both ends opened is fixed to the upper surface of the long lid 38. A guide groove 1 is formed on the inner peripheral wall of the holder 124 along the longitudinal direction.
26 is extended. A guide projection 130 is provided in the guide groove 126 so as to project from a cap 128 of the developer cartridge 10, and the developer cartridge 10 is loaded into the holder 124. The developer cartridge 10 includes a cylindrical housing portion 86, and the housing portion 86.
And a cylindrical recovery case 120 fitted into the opening. A receiving port 6 is provided on the outer peripheral surface of the collecting case 120.
A supply port 80 is formed at a position corresponding to 4, and an intake port 82 is formed at a position corresponding to the discharge port 74.

The collection case 120 has a cylindrical collection box 132 into which the cap 131 is pressed. When the collection box 132 is fitted into the collection case 120, its end surface 84 serves as a partition wall (see FIG. 3) to partition the supply port 80 and the intake port 82. This prevents the developer L stored in the storage section 86 from flowing into the collection box 132.
A part of the end face 84 projects in the longitudinal direction to form the overhanging piece 1.
34 (see FIG. 5). The opening 136 formed in the overhanging piece 134 communicates with the intake port 82 when the collection box 132 is fitted into the collection case 120. Thereby, the collection box 132
The carrier is collected through the outlet 74, the inlet 82, and the opening 136. As shown in FIG. 3, an agitator 88 is provided in the storage unit 86, and the stored developer L is stirred and conveyed to the supply port 80.

The collection case 120 and the collection box 1
Although not shown, the joint with the tape 32 is taped, so that only the collection box 132 can be removed as needed. This facilitates the processing of the carrier accumulated in the collection box 132. Further, the volume of the collection box 132 is set to a size capable of collecting all the carriers contained in the developer stored in the developer cartridge 10.

The periphery of the supply port 80 and the intake port 82 is cut down along the circumferential direction, and a guide groove (not shown) is formed. A shutter 98 curved in an arc shape along the developer cartridge 10 is attached to the guide groove so as to be slidable in the circumferential direction. On the upper surface of the shutter 98, a long groove 138 is formed in the width direction. The long groove 138 engages with a protrusion 140 protruding from the lower end of the receiving plate 76, and when the long plate-shaped handle 100 provided on the cap 131 is picked and turned with a finger, the developer cartridge 10 is turned. The supply port 80 and the intake port 82 are opened and closed.

A cylindrical slide cover 102 is slidably mounted so as to surround the collection case 120. The slide cover 102 is urged by a spring 104 in a direction to cover the shutter 98.
For this reason, when the developer cartridge 10 is not mounted, the shutter 98 is covered by the urging force of the spring 104. When the developer cartridge 10 is mounted on the rotating body 34, the inclined open end of the slide cover 102 is The shutter 98 is exposed by the operation of inserting the developer cartridge 10 when the stopper 98 is hit.

FIG. 9 is a cross-sectional view of the collecting box 132 for storing the collected developer L. In FIG. 9, the collecting box 132 is positioned vertically with respect to the rotating shaft 34a of the rotating body 34.
The state of two collection boxes 132a and 132b is shown. FIG. 10 is a cross-sectional view taken along line AA of the collection box 132a located above the rotation shaft 34a.

The collection box 132 of the present invention has a cylindrical side surface 141 extending in the longitudinal direction of the developer cartridge.
And an end surface 84 inclined by a predetermined angle with respect to a plane orthogonal to the long axis, and a cap 131 is fitted to the opposite end of the end surface 84. The angle θ between the end surface 84 of the collection box 132 and the side surface 141 thereof
A developer collecting port 146 communicating with the opening 136 provided in the overhanging piece 134 is opened on the side where is an obtuse angle (lower side in the collecting box 132a).

In the collection box 132, there is provided a shutter mechanism that opens the developer collection port 146 within a predetermined rotation angle range and closes it outside the predetermined rotation angle range.
For example, the shutter mechanism closes when the collection box 132 is positioned above the rotation shaft 34a, and opens when the collection box 132 is positioned below the rotation shaft 34a.

This shutter mechanism has a weight 14 at its free end.
The plate-shaped elastic member 143 is fixed to the developer recovery box 132. The fixed member 144 fixes the plate-shaped elastic member 143 in the developer collection box 132. The free end of the plate-like elastic body 143 is pressed against the developer recovery port 146 outside the predetermined rotation angle range by the gravity of the weight 142, and is fixed so as to be separated from the developer recovery port 146 within the predetermined rotation angle range. Have been.

In such a configuration, the collection box 1
32b, the free end of the plate-like elastic body 143 is in a position in which the developer recovery port 146 is located above (the antigravity side) in the end surface 84 as a result. Is separated from the recovery port 146 by the gravity F of the weight 142. Therefore, the developer L discharged from the developing device 12 is collected into the collection box 132 from the collection port 146. In addition, in this position, the recovery port 146 is located above the center of the end face 84, so that the developer L can be stored beyond the center of the end face 84. The fixing member 1
44, the free end of the plate-like elastic body 143 is connected to the developer collecting port 1
A support portion 144a is provided for restricting a change in the posture so as not to remain at a predetermined distance from 46.

On the other hand, when the developer recovery port 146 is located above the rotation shaft 34a as in the case of the recovery box 132a and the developer recovery port 146 is located on the lower side (gravity side) in the end surface 84, the weight 142 Elastic body 143 by the gravity F of
Is pressed against the recovery port 146. For this reason,
The developer L in the collection box 132a does not flow back to the outside. In the present embodiment, the plate-like elastic body 14
3, since the slit 143a is formed in the longitudinal direction, when the plate-like elastic body 143 is pressed against the recovery port 146, the developer that has entered between the end surface 84 and the elastic body 143 easily moves to the opposite side through the slit 143a. Can be moved to
The operation of the plate-like elastic body 143 is not hindered by the developer.

FIG. 12 shows the relationship between the number of rotations of the rotating body 34 and the amount of developer collected in the collection box 132.
It is the figure which compared using the collection box from which the position of a collection port differs with the same capacity. In the prior art in which the collection port is opened at the center of the end face, as plotted with a black circle, the collection amount does not increase when the number of rotations exceeds about 200 rotations,
In the present embodiment plotted with squares, the collection amount continues to increase up to 550 times when the developer cartridge reaches the end of its life. FIG. 13 is a graph showing the relationship between the number of rotations of the rotating body 34 and the amount of developer remaining in the developing device.
While the number of rotations suddenly increases when the rotation exceeds the rotation, in the present embodiment, it is always within the range of 380 grams or 400 grams.

As described above, according to the present embodiment, only the effective volume of the developer collecting box 132 can be increased without increasing the size of the developer collecting box 132. The agent can be continuously collected. Accordingly, the carrier exchange is always performed, so that not only a stable image can be always obtained, but also the toner concentration of the two-component developer (that is, the ratio of the toner weight to the total weight of the carrier and the toner) is stabilized, so that a high image quality can be obtained. Image quality can be obtained.

In the above-described embodiment, the present invention has been described as applied to a color printer. However, the present invention is not limited to this, and is similarly applicable to other image forming apparatuses such as a color copying machine and a facsimile machine. Can be applied.

[0032]

As described above, according to the present invention, the following effects can be achieved. (1) According to the first aspect of the invention, it is possible to prevent the developer collected in the developer collection box from flowing back to the developing device side. (2) According to the second aspect of the present invention, the shutter mechanism provided in the developer collection port automatically opens and closes in accordance with the position of the collection box. If the closing operation is performed and the opening operation is performed in other postures, the developer can be collected without flowing backward. (3) According to the third aspect of the present invention, the shutter mechanism opens when the developer collection port is above the center position of the end face, and closes when the developer collection port is below the center position. Without increasing the effective volume. (4) According to the invention of claim 4, sag of the plate-like elastic body can be prevented. (5) According to the invention of claim 5, when the plate-like elastic body is pressed against the collection port, the developer that has entered between the end face and the elastic body can easily move to the opposite side through the slit.
The movement of the plate-like elastic body is not hindered by the developer. (6) According to the seventh aspect of the present invention, it is possible to provide an image forming apparatus in which a large number of carriers can be replaced by a single cartridge replacement.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a developing device and a developer cartridge of a rotary developing device to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a state in which a developing device and a developer cartridge are attached to a rotary developing device.

FIG. 3 is a cross-sectional view illustrating a state where a developer cartridge is assembled to a developing device.

FIG. 4 is an enlarged sectional view of a developing device and a developer cartridge.

FIG. 5 is an exploded perspective view of the developer cartridge.

FIG. 6 is an enlarged perspective view of a developing device.

FIG. 7 is an enlarged perspective view of a long lid of the developing device.

FIG. 8 is an enlarged perspective view of a developer cartridge.

FIG. 9 is a cross-sectional view illustrating a movement of a shutter in a collection box having a different posture.

FIG. 10 is a sectional view of a collection box.

FIG. 11 is a sectional view of a conventional collection box.

FIG. 12 is a diagram illustrating a relationship between the number of rotations of a rotating body and a collected amount of developer collected in a collection box.

FIG. 13 is a diagram illustrating a relationship between the number of rotations of a rotating body and the amount of developer remaining in a developing device.

[Explanation of symbols]

Reference Signs List 10: developer cartridge, 12: developing device, 34: rotating body, 66: receiving plate, 68: slide shutter, 12
0: collection case, 132: developer collection box

Claims (7)

[Claims] 1. A cylindrical developer cartridge in which a developer collection box is mounted at one end of a cylindrical developer accommodating portion for accommodating a developer containing at least a toner and a carrier, wherein the developer is opened to the collection box. A developer cartridge, wherein a shutter mechanism is provided at a collection port to prevent the collected developer from flowing out. 2. The collection port is opened near an end of an end surface intersecting with a long axis of the developer cartridge. The shutter mechanism is configured to rotate the collection box when the collection box is rotated about the axis.
2. The developer cartridge according to claim 1, wherein the recovery port is opened within a predetermined range within one rotation, and is closed outside the predetermined range. 3. An end face of the collection box is inclined at a predetermined angle with respect to a plane orthogonal to the long axis, and a collection port is opened at a side forming an obtuse angle with a side surface of the collection box. A longitudinal plate-like elastic body supported in a cantilever manner and having a fixed weight at a free end, and fixing means for fixing the plate-like elastic body to a collection box; and a weight of the plate-like elastic body. The gravitational force acts to press the free end of the collection box to the collection port if the collection box is outside the predetermined range, and to separate the collection box from the collection port if the collection box is within the predetermined range. 3. The developer cartridge according to 2. 4. The apparatus according to claim 3, wherein said fixing means further comprises means for restricting the movement of one end of said plate-shaped elastic body so that said one end is not separated from said collection port by a predetermined distance or more. The developer cartridge according to claim 1. 5. The plate-like elastic body has a slit formed in a longitudinal direction thereof.
3. The developer cartridge according to claim 1. 6. The range in which the shutter mechanism is to be opened is a range in which the collection port is located on the anti-gravity direction side in the end face of the collection box.
The developer cartridge according to any one of the above. 7. A developing device to which the developer cartridge according to claim 1 is detachably mounted, and a rotating device that rotates while holding a plurality of developing devices concentrically around a rotation shaft. And a control unit for controlling the rotation of the rotating body so that each of the developing units is sequentially arranged to face the rotating drum. Excess developer in the developing unit is rotated by the rotating body to form a developer cartridge. The image forming apparatus according to claim 1, wherein the developer cartridge is attached to the developing device such that a collection port of the collection box is positioned on the rotation shaft side in an end surface of the developer cartridge. apparatus.