JPH10319665A - Color electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color electrophotographic device capable of saving resources by making a service life prolonged, a running cost lowered, and waste toner reduced, in a small size, at high speed, through simple constitution that is to say, providing a path spatially connecting the waste toner box with a development hopper. SOLUTION: As for this device, the image forming unit is provided with an electrifying device 10, an organic photoreceptor 9 forming the toner image, the development hopper 14 for gathering the toner, and the waste toner box 51 for gathering the waste toner recovered by a cleaning blade 27. The plural image forming unit is respectively arrayed in a annular shape and a whole body is made possible to rotate as one body, and the path 52 spatially connecting the waste toner box 51 with the development hopper 14 is disposed. Thus, the totter is allowed to pass through the path 52, and the toner is made possible to freely shift between the development hopper 14 and the waste toner box 51, therefore the waste toner becomes available for developing again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color printer,
The present invention relates to a color electrophotographic apparatus applicable to a color copying machine, a color facsimile, and the like.

[0002]

2. Description of the Related Art In general, in order to form a color image by using an electrophotographic method, a method of forming a color image by superimposing toner images of respective colors of yellow, magenta, cyan and black on a transfer material is adopted. Have been. As a method of forming a color image, an intermediate transfer method, a transfer drum method, a tandem method, and the like are generally used.

[0003] The intermediate transfer system is a system in which toner images of each color are sequentially formed on a single photosensitive member, and the toner images are sequentially superimposed on a transfer belt for primary transfer, and then collectively secondary transferred onto paper. It is. The transfer drum system is a system in which a toner image of each color is sequentially formed on one photoconductor, and the toner images are sequentially superimposed on paper wrapped in advance on a transfer drum. The tandem method is a method in which a plurality of image forming units are arranged side by side, a toner image of each color is formed by parallel processing, and the toner images are transferred in parallel onto a transfer material conveyed by a belt.

However, such a conventional color electrophotographic apparatus usually requires image forming means and developing means for four colors, so that the apparatus becomes larger than a monochrome electrophotographic apparatus.
A color electrophotographic apparatus which solves such a problem is proposed in Japanese Patent Application Laid-Open No. 7-36246. This is 4
By sequentially forming toner images of each color using a rotating image forming unit including two photoconductors, and sequentially superimposing the toner images on a transfer belt, the maintenance of the apparatus is improved and the size of the apparatus is reduced. .

Hereinafter, a specific example will be described with reference to the drawings. FIG. 11 is a sectional view showing an example of the conventional color electrophotographic apparatus. In the center of the apparatus, four fan-shaped image forming units 4Y, 4M, 4C, and 4B of yellow, magenta, cyan, and black form an image forming unit group, and are arranged in an annular shape.

An image forming unit 4 arranged in an annular shape
B, 4Y, 4M, and 4C are supported by a support (not shown). These image forming units are integrally driven by a moving motor 30 which is moving means controlled by a control circuit 29. By this driving, each image forming unit rotates in the direction of arrow E around a cylindrical fixed shaft 31 which does not rotate.

Each image forming unit is moved to and positioned at an image forming position facing a transfer roller 33 which supports an intermediate transfer belt 32 described later. The support of each image forming unit has a unit (not shown) for detecting that each image forming unit has moved to the image forming position, and each time the movement of each image forming unit is completed, it corresponds to the completion of the movement. Signal to control circuit 2
9

The signal light 1 by the laser beam modulated by the signal input to the printer unit by the laser exposure device 3
Generates 3. The signal light 13 is transmitted to the image forming units 4B and 4B.
C, passes through an optical path formed through the transparent window 4 opened in a part of the shaft 31, enters the optical correction means 5 fixed inside the shaft 31, and is reflected to the image forming position. The organic photoreceptor 9 of a certain image forming unit is irradiated to form a latent image. In the state of FIG. 11, the signal light 13 acts on the image forming unit 4B for black.

The optical path up to the optical correction means 5 is along the wall of the fan-shaped image forming unit. That is, the space between the wall surfaces of adjacent image forming units is used as an optical path.
Therefore, the occupied space of the image forming unit group has almost no wasted portion. In addition, since the optical correction unit 5 is provided at the center of the image forming unit group, it is simple and has high reliability for alignment and the like. As the optical correction unit 5, a cylindrical lens, a cylinder mirror, or the like is used.

In this method in which the optical correction means 5 is provided at the center of the image forming unit group, all conventional optical corrections are performed in the exposure apparatus 3 and a simple plane mirror is installed inside the shaft 31 to direct the laser beam. Compared to the conversion method, since the optical correction is performed near the image forming position, a unique effect that the accuracy of the positional deviation at the image forming position of the laser beam and the accuracy of the beam shape is increased.

Further, since the optical path is set so that the reflection surface of the optical correction means 5 faces downward, dust and the like in the apparatus hardly accumulate. The intermediate transfer belt 32 has a thickness of 10
An endless belt-like film of 0 μm made of semiconductive urethane as a base material. Transfer roller 33 and stainless steel roller 34 around which urethane foam is formed
And can be moved in the direction of arrow B.

The transfer roller 33 is lightly pressed against the organic photosensitive member 9 of the image forming unit 4B via the intermediate transfer belt 32. A second transfer roller 35 having the same configuration as the above-described transfer roller 33 is provided on the roller 34 via the intermediate transfer belt 32.
However, it is lightly pressed so that it can be driven to rotate. A nip portion where the intermediate transfer belt 32 and the second transfer roller 35 are pressed against each other is
A paper transport path is formed so that paper is sent from the paper supply unit 36.

The belt cleaner 4 of the belt cleaner section 40
By 0a, the intermediate transfer belt 32 is cleaned. The fixing device 44 is a fixing device for fixing the toner image on the paper after the transfer.
The sheet after fixing is discharged by a discharge roller 45.

According to the above electrophotographic apparatus, 4
By arranging one image forming unit in an annular shape and rotating the whole, it is possible to reduce the size in comparison with other types of color electrophotographic apparatuses.

[0015]

However, the above-described color electrophotographic apparatus has the following problems.

(1) According to the color electrophotographic apparatus described above, the apparatus can be reduced in size as a whole, but it does not reduce the size of the image forming unit itself or extend its life. In general, a color image has a larger image area ratio and consumes a larger amount of toner than a monochrome image. For this reason, the running cost is higher and the cycle of actual cartridge replacement and toner replenishment is shorter than in a black-and-white electrophotographic apparatus. For this reason, the life of the image forming unit is shorter than that of a black-and-white electrophotographic apparatus if the size is the same. With color electrophotographic devices as described above, this problem has not been solved.

(2) If the capacity of the toner in the developing hopper and the capacity of the waste toner box in the cleaner portion are increased, the service life can be extended for a while, but the outer diameter of the image forming unit group is increased. The whole device becomes large.

(3) When the size of the entire apparatus is increased, the rotational moment of the image forming unit group is increased, the mechanism for rotating and stopping the image forming unit group is also increased at the same time, and the switching speed of the image forming unit is slow. turn into.

The color electrophotographic apparatus according to the present invention solves the above-mentioned problem, and has a small size, high speed, and low image speed by a simple structure having a passage for spatially connecting the waste toner box and the developing hopper. It is an object of the present invention to provide a color electrophotographic apparatus in which the life of a forming unit is long, running costs are low, and resources can be saved by reusing waste toner.

[0020]

In order to achieve the above object, a color electrophotographic apparatus according to the present invention comprises a charging means, an electrostatic latent image holder for forming toner images of different colors, and a toner. Developing means including a developing hopper for storing
A plurality of image forming units arranged in a ring and rotatable integrally with each other; and a plurality of image forming units arranged in a ring and integrally rotatable. Transfer means for transferring the toner image on the electrostatic latent image holding body to a transfer material, laser exposure means for performing image exposure on the electrostatic latent image holding body at the image forming position, and rotating the image forming unit, A moving means for sequentially positioning each of the image forming units at the image forming position, wherein the waste toner box of each of the image forming units and the developing hopper are spatially connected. It is characterized by having a passage.
According to the color electrophotographic apparatus as described above, the simple configuration in which the waste toner box and the developing hopper are spatially connected to each other provides a small-sized, long cartridge life, low running cost, and low waste toner. A color electrophotographic apparatus that can save resources by reuse can be obtained.

In the color electrophotographic apparatus, the rotation direction of each of the image forming units is such that the image forming positions of each of the image forming units are in the order of the developing hopper, the passage, and the waste toner box. Preferably, it is the direction in which the image forming unit passes. With the rotation direction as described above, the backflow of the toner into the waste toner box when the image forming unit is at the image forming position can be reduced.

In the color electrophotographic apparatus, the inclination of the inner wall of the waste toner box is such that the toner in the waste toner box moves to the passage by gravity during rotation of the image forming unit. Preferably, it is provided.

Further, in the color electrophotographic apparatus, a plurality of toners in the waste toner box move on the inner wall of the waste toner box so that the toner in the waste toner box moves to the passage by gravity during rotation of the image forming unit. It is preferable that the inclination is formed in a zigzag shape, and each inclination is inclined toward the passage with the opposite side as the apex.

As described above, by providing the inner wall of the waste toner box with an inclination, the toner in the waste toner box can be efficiently moved to the passage. Further, in the color electrophotographic apparatus, both ends are supported by the waste toner box, and by having a weight, the relative rotation with respect to the image forming unit whose posture does not change even by the rotation of the image forming unit, With a stirring member formed in a spiral or screw shape,
It is preferable that the toner in the waste toner box is transferred to the passage by the relative rotation of the stirring member. By providing the stirring member as described above, the toner in the waste toner box can be efficiently moved to the passage.

In a preferred color electrophotographic apparatus provided with the stirring member, it is preferable that the spiral shape is formed by processing a linear material. Further, in the color electrophotographic apparatus, it is preferable that the passage is formed at both ends of the image forming unit in the rotation axis direction.

In a preferred color electrophotographic apparatus having a passage formed at both ends, the toner in the waste toner box is formed at both ends by gravity during rotation of the image forming unit. It is preferable that an inclination to each passage having a vertex at the center in the rotation axis direction of the image forming unit is provided on the inner wall of the waste toner box so that the waste toner box moves.

Also, a plurality of inclined walls are provided on the inner wall of the waste toner box so that the toner in the waste toner box moves to the respective passages formed at both ends by gravity while the image forming unit is rotating. Are formed in a zigzag shape,
Each slope on the right side with respect to the center part in the rotation axis direction of the image forming unit is inclined toward the right passage side with the center part side as a vertex, and each slope on the left side with the center part side as a vertex on the left passage side. It is preferable that it is inclined.

As described above, by providing the inner wall of the waste toner box with an inclination, the toner in the waste toner box can be efficiently moved to each passage at both ends.
Further, both ends are supported by the waste toner box,
By having a weight, the image forming unit rotates relative to the image forming unit whose attitude does not change even by the rotation of the image forming unit, and a spiral shape or a screw shape is formed. It is preferable that a stirring member having a different shape or a screw shape is provided, and the toner in the waste toner box is transferred to each of the paths at the both ends by the relative rotation of the stirring member.

As described above, the provision of the stirring member allows the toner in the waste toner box to be efficiently moved to the respective passages at both ends. Preferably, the spiral shape is formed by processing a linear material.

Further, in the color electrophotographic apparatus, when gravity acts on the passage in a direction in which toner moves from the developing hopper side to the waste toner box side, the passage is closed, and the waste toner box is closed. When gravity acts in a direction in which the toner moves from the side to the developing hopper side, it is preferable that an on-off valve for opening the passage is provided. In a preferred color electrophotographic apparatus provided with the on-off valve, the on-off valve is fixed to the passage by a hinge, and the on-off valve preferably opens and closes the passage with a rotation axis of the hinge as a fulcrum. .

As described above, the provision of the open / close valve can prevent toner from flowing back into the waste toner box when the image forming unit is at the image forming position, regardless of the rotation direction.

In the above-described color electrophotographic apparatus, it is preferable that the order of each color toner to be transferred to the transfer material be in the order of higher transparency. In a preferred color electrophotographic apparatus for transferring images in the order of higher light transmittance, the toner colors are yellow, magenta, cyan, and black, and the order of each color toner transferred to the transfer material is yellow, magenta, and cyan. , Black, or yellow, cyan, magenta, and black. With the transfer order as described above, it is possible to prevent color turbidity on the transfer material.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color electrophotographic apparatus according to the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view showing an entire color electrophotographic apparatus according to Embodiment 1 of the present invention. Components that are the same as those of the conventional example described with reference to FIG. 11 are denoted by the same reference numerals, and detailed description is omitted. Each image forming unit 1Y (for yellow), 1M (for magenta), 1C (for cyan), 1B
(For black) has the same configuration except for the toner color, and therefore, the configuration will be described with the image forming unit for yellow as a representative.

FIG. 2 is a longitudinal sectional view of the image forming unit according to the first embodiment at both ends in the rotation axis direction. The organic photoreceptor cover 28 is a cover for protecting the organic photoreceptor 9, and FIG. 2 shows an open state for image formation.

The developing hopper 14 and the waste toner box 51 are connected by a passage 52. Two passages 52 are provided at both ends in the longitudinal direction of the image forming unit 1Y. The toner can freely move between the developing hopper 14 and the waste toner box 51 through the passage 52.

FIG. 3 is a longitudinal sectional view of a central portion in the rotation axis direction of an example of the image forming unit according to the first embodiment. As shown in the figure, the image forming unit 1
At the center in the longitudinal direction of Y, the developing hopper 14 and the waste toner box 51 are separated, and the exposure signal 13 by the laser can pass through the gap.

As the toner 25Y, a non-magnetic yellow component was used. This toner 25Y has an average particle size of 9.
This is a dispersion in which a pigment as a colorant, a charge control agent, and a fixing improver are dispersed in a polyester resin, and a toner surface modifier is added. The developing hopper 14, the passage 52, and the waste toner box 51 are filled with 250 g of the toner 25Y.

Next, the operation of the color electrophotographic apparatus according to the first embodiment will be described with reference to FIGS. First, a yellow image is formed by the yellow image forming unit 1Y. The organic photoreceptor 9, which is a phthalocyanine-based electrostatic latent image holding member, is charged by the charger 10 to −70.
The organic photoreceptor 9 was negatively charged to 0 V and irradiated with an exposure signal 13 by a laser to form an electrostatic latent image. At this time, the entire surface exposure potential of the organic photoreceptor was -100V.

The surface of the organic photoconductor 9 is opposed to an aluminum developing roller 19 carrying toner 25Y and rotating at the same speed in the same direction as the organic photoconductor 9. A voltage obtained by superimposing a 750 V (0 to peak) sine wave AC bias having a frequency of 2 kHz on a DC voltage of 500 V was applied. As a result, only the negative-positive toner image remained on the organic photoreceptor 9 only in the image area. The toner image on the organic photoconductor 9 is transferred to the intermediate transfer belt 32 at the image forming position.

The toner in the developing hopper 14 is supplied to the developing roller 19 by a toner supply roller 21 formed of a urethane material. Also, the toner layer regulating blade 2
2, the thickness of the toner layer on the developing roller 19 is regulated.

Further, the diameter of the organic photoreceptor 9 is set to 30 mm, and the organic photoreceptor 9 is rotated at a peripheral speed of 150 mm / s in the direction of arrow C (FIG. 2).
It was rotated in the direction of arrow D (FIG. 2) at m / s.

Image forming unit group 1Y, 1M, 1C, 1B
The whole is driven by the moving motor 30 and integrally rotates in the direction of arrow A in FIG. When the transfer of the yellow toner image to the intermediate transfer belt 32 is completed, the image forming unit 1M is rotated by exactly 90 degrees from the state shown in FIG. 1 and stops at the position where the image forming unit 1M reaches the image forming position, and the image forming unit 1M is positioned. Is done. Since the portion of each image forming unit other than the organic photoreceptor 9 is located inside the rotation arc at the tip of the organic photoreceptor 9, the intermediate transfer belt 32 does not contact each image forming unit.

As in the case of the image forming unit 1Y, the laser exposure device inputs a signal light to the image forming unit 1M with a magenta signal to form and transfer a magenta toner image. At this time, the timing of writing the magenta signal light is controlled such that the next magenta toner image is positionally matched to the yellow toner image previously transferred onto the intermediate transfer belt 32.

During this time, the second transfer roller 35 and the belt cleaner 40a of the cleaner section 40 are slightly separated from the intermediate transfer belt 32, and do not affect the toner on the intermediate transfer belt 32. The same operation is performed for cyan and black, and toner images of four colors are superimposed on the intermediate transfer belt in a position-matching manner to form a color image.

After the transfer of the last black toner image, the toner images of the four colors are collectively transferred to the sheet sent from the sheet feeding section 36 at the same time by the action of the second transfer roller 35. Further, the toner image transferred to the sheet is fixed by a fixing device 44, and the sheet is discharged outside the apparatus via a discharge roller 45.

The residual toner on the organic photoreceptor 9 after the transfer of the toner image of each color is removed by the cleaning blade 27. The removed toner is temporarily stored in the waste toner box 51. By the rotation of the image forming unit group, the toner stored in the waste toner box 51 is
It is gradually returned to the developing hopper 14 through the passage 52 and is used again for developing.

Hereinafter, the movement of the toner in the image forming unit 1Y will be described more specifically with reference to FIG. When the transfer of the yellow image is completed, the image forming unit 1Y rotates in the direction of arrow A and moves to the position of the image forming unit 1B in FIG. At this position, the toner in the waste toner box 51 moves toward the developing hopper 14 through the passage 52 by the action of gravity.

Next, when the image forming unit 1Y moves to the position of the image forming unit 1C in FIG. 1, most of the toner is collected on the developing hopper 14 by the action of gravity. In other words, the toner in the waste toner box 51 after the transfer is transferred to the developing hopper 14 once.

Further, the image forming unit 1Y rotates in the direction of arrow A, and returns to the image forming position via the position of the image forming unit 1M in FIG. During this time, part of the toner passes through the passage 52 by the action of gravity and
It will return to 1. However, since the toner has a certain resistance to the flow, the reverse flow of the toner is suppressed to a certain small amount, and a sufficient amount of toner necessary for transfer is secured in the developing hopper 14.

Further, the inside of the waste toner box 51 is in a state where there is no toner once as described above. Therefore, a sufficient space for filling the toner is ensured. Further, as described above, since the amount of the backflow of the toner is small, even if the toner flows back into the waste toner box 51, it does not reach the level where the entire waste toner box 51 is filled. That is, since the toner does not reach the cleaning blade 27, cleaning failure can be prevented.

As the transfer is repeated and the amount of toner decreases, the effect of gravity on the toner also weakens, so that the above-mentioned toner backflow becomes smaller. Therefore, the waste toner can be continuously reused, and most of the toner stays in the developing hopper 14, so that the toner can be effectively used.

Since the rotation direction of the image forming units is set in the direction of arrow A, the developing hopper 14 of each image forming unit
Each of the image forming units passes through the image forming position in the order of the image forming unit, the passage 52, and the waste toner box 51. The reason for setting the direction of the arrow A is that the reverse flow rate of the toner is smaller than that in the case where the direction is reversed.

For example, the direction of moving from the position of the image forming unit 1M to the position of 1Y (arrow A direction) in FIG. 1 (direction of arrow A) is the direction of moving from the position of the image forming unit 1B of FIG. 1 to the position of 1Y (arrow A). (In the direction opposite to the direction), the action of gravity for moving the toner in the developing hopper 14 to the waste toner box 51 side is weaker. This is because, in the direction opposite to the arrow A, the toner has already gathered to the side of the passage 52 at the position of the image forming unit 1B in FIG. This is because at the position of the image forming unit 1M, most of the toner is gathered near the image forming portion, and there is not much toner near the passage 52.

In the first embodiment, the initial toner amount 25
With 0 g, 11,500 sheets of prints equivalent to an A4 blackening ratio of 5% could be output. After outputting 11,500 sheets, only about 20 g of toner was left in the image forming unit. As a result of analyzing the toner remaining in the image forming unit, no foreign matter such as paper dust was found to be mixed at all.

Next, as a comparative experiment, similar color printing was performed using an image forming unit having no passage 52 connecting the developing hopper 14 and the waste toner box 51.
In this case, the only space in which the toner can be stored is the developing hopper 14, so that the initial chargeable toner amount is 200.
g, and the number of printable sheets corresponding to an A4 blackening ratio of 5% is 810.
It was 0 sheets. The amount of toner remaining in the image forming unit after printing 8100 sheets was about 20 g in the developing hopper 14 and about 20 g in the waste toner box 29, for a total of about 40 g.

As described above, in the color electrophotographic apparatus of the present invention, since the waste toner box and the developing hopper are spatially connected by the passage, the waste toner can be reused. Further, since the toner can be stored in both the waste toner box and the developing hopper, the space of the image forming unit can be effectively used, and the size of the image forming unit can be reduced. In other words, a simple configuration of providing a space that connects the waste toner box and the developing hopper spatially provides a small size, a long cartridge life, low running cost, and resource saving by recycling waste toner. A photographic device can be obtained. (Embodiment 2) A color electrophotographic apparatus according to Embodiment 2 of the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 4 is a sectional view showing the entire color electrophotographic apparatus according to Embodiment 2 of the present invention.

The color electrophotographic apparatus according to Embodiment 2
The image forming unit is different from that of the first embodiment.
The image forming units 2Y (for yellow), 2M (for magenta), 2C (for cyan), and 2B (for black) have the same configuration except for the toner color. It will be described as.

At the center of the image forming unit 2Y in the rotation axis direction, as in the first embodiment shown in FIG.
The developing hopper 14 and the waste toner box 51 are separated from each other, and the exposure signal 13 by the laser can pass through the gap.

FIG. 5 is a longitudinal sectional view at both ends in the rotation axis direction of the yellow image forming unit 2Y. The passage 52 is provided with an on-off valve 53. The on-off valve 53 has a range F with the rotation axis of the hinge 54 as a fulcrum.
It is freely rotatable within. FIG. 5 shows a state in which the on-off valve 53 is in contact with the rotation stopper 2a under the action of gravity. That is, in this state, the on-off valve 53
The passage 52 is closed.

The developing hopper 14, the passage 52 and the waste toner box 51 are filled with 250 g of the same yellow non-magnetic one-component toner 25Y as in the first embodiment. The diameter of the organic photoreceptor 9 is 30 mm, and the peripheral speed is 50 mm.
/ S was rotated in the direction of arrow C, the diameter of the developing roller 19 was 15 mm, and the developing roller 19 was rotated in the direction of arrow D at a peripheral speed of 50 mm / s.

Next, the operation of the color electrophotographic apparatus according to the second embodiment will be described with reference to FIG. After the transfer of the toner image, the image forming unit 2Y rotates in the direction of arrow E. When the image forming unit 2Y reaches the position of the image forming unit 2C via the position of the image forming unit 2B in FIG. 4, the toner in the waste toner box 51 tries to move toward the developing hopper 14 by the action of gravity. I do. at the same time,
Since the on-off valve 53 is opened by the action of gravity, toner flows from the waste toner box 51 through the passage 52 to the developing hopper 14.
Will be moved to. According to the experiment, it was confirmed that the toner was quickly moved from the waste toner box 51 to the developing hopper 14.

Further, the image forming unit 2Y rotates in the direction of arrow E and passes through the position of the image forming unit 2M in FIG.
It will return to the image forming position again. At the image forming position, the toner in the developing hopper 14 tends to move to the waste toner box 51 side by the action of gravity, but at the same time, the on-off valve 53 comes into contact with the rotation stopper 2a by the action of gravity, and the passage 52 is closed. I'm blocking. That is, the on-off valve 53 can prevent the toner from flowing backward from the developing hopper 14 to the waste toner box 51. According to the experiment, it was confirmed that there was almost no backflow of the toner from the developing hopper 14 to the waste toner box 51.

In the second embodiment, the initial toner amount 25
With 0 g, 11,500 sheets of printing corresponding to an A4 blackening ratio of 5% could be output. After outputting 11,500 sheets, only about 20 g of toner was left in the image forming unit.
As a result of analyzing the toner remaining in the image forming unit, no foreign matter such as paper dust was found to be mixed at all.

As described above, in the second embodiment, since the backflow of the toner in the developing hopper 14 can be prevented, the toner can be effectively used for transfer. Further, since the backflow can be prevented, the amount of toner remaining in the waste toner box 51 becomes small. For this reason, since the toner does not reach the vicinity of the cleaning blade due to the backflow of the toner, cleaning failure can be prevented.

That is, the color electrophotographic apparatus is small in size, has a long cartridge life, and has a low running cost due to a simple structure in which a passage for connecting the waste toner box and the developing hopper spatially is provided and a hinge is provided in the passage. Can be obtained.

In this embodiment, the direction of rotation of the image forming unit group is the direction of arrow E in FIG. 4. However, even in the opposite direction, the passage is closed by the opening / closing door at the image forming position. The same effect as in the case of the direction of arrow E is obtained. This was confirmed by experiments. (Embodiment 3) A color electrophotographic apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS. In the third embodiment, a small particle size toner is used as the toner. The third embodiment has the same configuration as that of the first embodiment except for the image forming unit. Therefore, only the configuration of the image forming unit will be described. Since the image forming units have the same configuration except for the toner color, the image forming unit for yellow will be described as a representative.

FIG. 6 is a longitudinal sectional view of the image forming unit according to the third embodiment at both ends in the rotation axis direction. Since the state shown in this figure is the same as the state shown in FIG. 2 of the first embodiment, the same number is assigned and the detailed description is omitted. The diameter of the organic photoreceptor 9 is 20 mm,
The developing roller 19 is rotated in the direction of arrow C at a peripheral speed of 100 mm / s.
Rotated in the direction.

The toner 25Y is a yellow non-magnetic one-component toner having an average particle size of 6.5 μm, a pigment as a colorant, a charge controlling agent, and a fixing improver dispersed in a polyester resin, and a toner surface modification. The agent was added. The developing hopper 14, the passage 52, and the waste toner box 51 are filled with 250 g of the toner 25Y.

FIG. 7 is a sectional view of the waste toner box 51 taken along the line II of FIG. As shown in FIG. 7, the inner wall of the waste toner box 51 is provided with slopes 58a and 58b that are inclined toward the respective passage sides at both ends with the central part 57 in the rotation axis direction of the image forming unit as the apex. Therefore, the rotation of the image forming unit moves the toner 25Y in the direction of the arrow in FIG. That is, the toner 25Y moves to the left and right passages.

The inner wall of the waste toner box 51 is not limited to the line II in FIG. 7, but is similarly formed in other places at the center from the center in the rotation axis direction of the image forming unit to both ends. I have.

The operation of the apparatus is the same as that of the first embodiment, and the description is omitted. Activate the device and
The state of the toner in the waste toner box 51 at the image forming position was observed every time printing was performed on 00 sheets. After printing 4000 sheets, it was confirmed that there was almost no toner in the waste toner box 51. Further, after 4000 sheets of printing, the toner in the waste toner box 51 moves to the developing hopper 14 through the passage 52 quickly, and the toner in the developing hopper 14 is also rotated by the rotation of the image forming unit. It was confirmed that there was no backflow to

The reason for the absence of toner backflow is that the toner has a certain resistance to flow, and the effect of gravity weakens as the amount of toner decreases due to repeated transfer.
This is because the toner easily stays in the developing hopper 14.

In the color electrophotographic apparatus according to the third embodiment, 14,600 sheets of prints corresponding to an A4 blackening ratio of 5% could be output with an initial toner amount of 250 g. Also, 14600
After the sheet output, only about 30 g of toner was left in the image forming unit.

The inclination formed on the inner wall of the waste toner box 51 is not limited to that shown in FIG. 7, and the same effect can be obtained even if a plurality of inclinations are formed. FIG. 8 shows a waste toner box 51 having a plurality of slopes.
7 is a cross-sectional view taken along line II of FIG.

A plurality of slopes are formed in a zigzag shape on the inner wall of the waste toner box. Each slope 59a on the right side of the center portion 57 in the rotation axis direction of the image forming unit is
With the 7 side as the apex, the right side is inclined toward the passage, and the left side is inclined 5
9b has a central portion 57 side as an apex and is inclined to the left passage side. Therefore, the toner moves in the direction of the arrow in FIG. 8 due to the rotation of the image forming unit. That is, the toner moves to the left and right passages.

Next, as a comparative experiment, the waste toner box 5
A similar experiment was performed using an image forming unit in which no inclination was formed on the inner wall of No. 1. In such a color electrophotographic apparatus, an A4 blackening ratio of 5
% Could be output only up to 12000 sheets. After 12,000 sheets were output, about 70 g of toner remained in the image forming unit, and about 40 g remained in the waste toner box 51, particularly in the central portion in the longitudinal direction.

A similar experiment was conducted using several types of toner. As a result, the fluidity of the toner and the waste toner box 5
It was found that there was a correlation with the amount of residual toner in 1. That is, in the case of a toner having poor fluidity such as a toner having a small particle diameter, the amount of residual toner tends to increase.

On the other hand, in the case of the apparatus according to the third embodiment in which the inner wall of the waste toner box 51 is inclined, the amount of the residual toner does not depend much on the fluidity of the toner. Also, almost no toner remained in the waste toner box 51.

As described above, according to the third embodiment, with a simple configuration in which the inner wall of the waste toner box is provided with an inclination,
It can handle toner with poor fluidity such as small particle size toner,
A color electrophotographic apparatus which is small in size, has a long cartridge life, low running cost, and can save resources by reusing waste toner can be obtained. (Embodiment 4) A color electrophotographic apparatus according to Embodiment 4 of the present invention will be described with reference to FIGS. In the fourth embodiment, as in the third embodiment, a small particle size toner is used as the toner. In the third embodiment, except for the image forming unit,
Since the configuration is the same as that of the first embodiment, only the image forming unit will be described. Since the image forming units have the same configuration except for the toner color, the image forming unit for yellow will be described as a representative.

FIG. 9 is a longitudinal sectional view at both ends in the rotation axis direction of the yellow image forming unit according to the third embodiment. The state shown in FIG.
5 is the same as that of the first embodiment described with reference to FIG. 2, and the same reference numerals are given and the detailed description is omitted. The diameter of the organic photoreceptor 9 is 20 mm, and the peripheral speed is 100 mm /
s in the direction of arrow C, and the developing roller 19
mm, it was rotated in the direction of arrow D at a peripheral speed of 100 mm / s.

As the toner 25Y, the same toner as in the third embodiment was used. The developing hopper 14, the passage 52, and the waste toner box 51 were filled with 250 g of the toner 25Y.
The stirring member 55 is formed by processing a wire into a spiral shape. FIG. 10 shows a view of the stirring member 55 viewed from the direction of arrow F in FIG. Shafts 55 a and 55 b formed at both ends of the stirring member 55 are supported by the waste toner box 51. For this reason, the stirring member 55 includes the shafts 55a and 55b.
You can freely rotate around.

A weight 56 is fixed to the stirring member 55. Since the weight 56 is fixed, the attitude of the stirring member 55 does not always change even when the image forming unit rotates. That is, regardless of the position of the image forming unit, the stirring member 55 maintains the state in which the weight 56 is on the lower side as shown in FIG.

Therefore, the stirring member 55 rotates apparently, that is, relatively rotates with respect to the image forming unit. Due to this relative rotation, the toner in the waste toner box 51 is transferred along a spiral formed on the stirring member 55. As shown in FIG. 10, the direction of the spiral is different from the center 59 of the stirring member 55. Therefore, by the relative rotation of the stirring member 55,
The toner on the right side of the central portion 59 is transferred to the right passage, and the toner on the left side of the central portion 59 is transferred to the left passage.

The operation of the apparatus is the same as that of the first embodiment, and a description thereof will be omitted. By operating the apparatus, the state of the toner inside the waste toner box 51 was observed at the image forming position every 1000 prints. It was confirmed that there was almost no toner in the waste toner box after printing 4000 sheets. Further, after 4000 sheets of printing, the toner in the waste toner box 51 moves to the developing hopper 14 through the passage 52 quickly, and the toner in the developing hopper 14 is also rotated by the rotation of the image forming unit. It was confirmed that there was no backflow to

The reason for the absence of toner backflow is that, as in the case of the third embodiment, the toner has a certain resistance to the flow, and the effect of gravity weakens as the toner decreases as the transfer is repeated. Is the developing hopper 14
This is because it is easy to stay inside.

Further, it was confirmed that the toner in the waste toner box 51 was gradually transferred from the center to the passages 52 at both ends along the spiral formed in the stirring member 55. As a result of the operation of the apparatus, 14,600 sheets of prints equivalent to an A4 blackening ratio of 5% could be output with an initial input toner amount of 250 g. After the output of 14,600 sheets, the image forming unit
Only about 30 g of toner was left.

Next, as a comparative experiment, the waste toner box 5
A similar experiment was carried out using an image forming unit in which the stirring member 55 was not provided in 1. As a result, the initial input toner amount 2
At 50 g, printing corresponding to an A4 blackening ratio of 5% could be output only up to 12,000 sheets. After outputting 12,000 sheets, about 70 g of toner remains in the image forming unit.
Approximately 40 g was in the waste toner box 51, especially at the center in the longitudinal direction.

A similar experiment was conducted using several types of toners. As a result, the fluidity of the toner and the waste toner box 5
It was found that there was a correlation with the residual amount of toner in 1.
That is, in the case of a toner having poor fluidity such as a toner having a small particle diameter, the amount of residual toner tends to increase.

On the other hand, in the apparatus according to the fourth embodiment in which the stirring member 55 is provided, the residual amount of the toner does not depend much on the fluidity of the toner. Also, almost no toner remained in the waste toner box 51.

As described above, according to the third embodiment, it is possible to cope with a toner having a low fluidity such as a toner having a small particle diameter with a simple configuration, and is small in size, has a long cartridge life, low running cost, and A color electrophotographic apparatus capable of saving resources by reusing toner can be obtained.

The stirring member 55 used in the third embodiment is used.
As shown in FIG. 10, a wire formed into a spiral shape as shown in FIG. 10 was used, but a wire formed in a screw shape may be used. In this case, the toner in the waste toner box 51 is transferred along the shape of the screw.

If the direction of the screw shape is reversed around the center of the stirring member 55, the toner on the right side of the center is transferred to the right passage by the relative rotation of the stirring member 55, and The left toner will be transported to the left passage.

In the first to fourth embodiments, the case where the image forming unit is used up is shown. However, the running cost can be further reduced by providing the toner replenishing means.

In the first to fourth embodiments, since the toner is superimposed on the transfer material, the amount of the toner on the transfer material transferred earlier is small when the image forming unit performs the transfer later. It is conceivable that the color of the toner in the image forming unit that performs reverse transfer and performs transfer later with time is turbid.

In the experiment, when the black toner was first transferred, the color turbidity became noticeable in the other image forming units, especially in the yellow image forming unit near the end of the life. On the other hand, when the yellow toner was first transferred and the black toner was last, color turbidity could not be recognized at all in the image forming units even near the end of the life.

Therefore, in the first to fourth embodiments, the order in which the toner of each color is transferred to the transfer material is yellow, magenta,
The order of cyan and black or the order of yellow, cyan, magenta and black is preferred. Further, even when using a color toner of another color, it is preferable to transfer from the one having the highest light transmittance.

Further, in the first to fourth embodiments, the case where the developing means is a non-contact developing method with a blade layer forming method has been described, but the developing means is not limited thereto. For example, a similar effect can be obtained by a rotating roller layer forming method or a counter blade layer forming method as a layer forming method, and a similar effect can be obtained by a contact developing method in contact with an organic photoreceptor as a developing method. Was.

[0098]

As described above, according to the color electrophotographic apparatus of the present invention, it has a simple structure in which a passage connecting the developing hopper and the waste toner box is provided, is small, has a long cartridge life, and has a low running cost. A low color electrophotographic apparatus can be obtained.

Also, by providing an on-off valve in the passage,
Backflow of the toner into the waste toner box can be prevented regardless of the rotation direction. Further, by providing the inner wall of the waste toner box with an inclination, the toner in the waste toner box can be efficiently moved to the passage.

By providing a stirring member in the waste toner box, the toner in the waste toner box can be efficiently moved to the passage. In addition, by transferring each color toner to the transfer material in order from the one having the highest light transmittance, the turbidity of the color on the transfer material can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an entire color electrophotographic apparatus according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view at both ends in the rotation axis direction of the image forming unit according to the first embodiment of the present invention;

FIG. 3 is a longitudinal sectional view of a central portion of the image forming unit according to the first embodiment of the present invention in the rotation axis direction.

FIG. 4 is a cross-sectional view showing the entire color electrophotographic apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a longitudinal sectional view at both ends in the rotation axis direction of an image forming unit according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view at both ends in a rotation axis direction of an image forming unit according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of the waste toner box taken along line II of FIG. 6;

FIG. 8 shows a waste toner box in which a plurality of slopes are formed in FIG.
Sectional view along line II

FIG. 9 is a longitudinal sectional view at both ends in the rotation axis direction of an image forming unit according to a third embodiment of the present invention.

FIG. 10 is a view of the stirring member viewed from the direction of arrow C in FIG. 9;

FIG. 11 is a cross-sectional view showing an example of a conventional color electrophotographic apparatus.

[Explanation of symbols]

 1Y, 2Y Yellow image forming unit 1M, 2M Magenta image forming unit 1C, 2C Cyan image forming unit 1B, 2B Black image forming unit 2a Rotation stop unit 3 Laser exposure device 9 Organic photoreceptor 14 Developing hopper 25Y Yellow Toner 27 Cleaning blade 32 Intermediate transfer belt 51 Waste toner box 52 Passage 53 Open / close valve 54 Hinge 55 Stirring member 56 Weight 57, 59 Central portion 58a, 58b, 59a, 59b in the rotation axis direction of the image forming unit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tadaaki Ohno 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (15)

[Claims] 1. A charging device, an electrostatic latent image holder for forming toner images of different colors, a developing device including a developing hopper for storing toner, a cleaning device, and a toner collected by the cleaning device. A plurality of image forming units arranged in an annular shape and rotatable integrally, and a toner image on the electrostatic latent image holding member is transferred at a single image forming position. Transfer means for transferring the image onto the material, laser exposure means for performing image exposure on the electrostatic latent image holding member at the image forming position, and rotating the image forming unit to move each of the image forming units to the image forming position. A moving means for sequentially positioning the waste toner box of each of the image forming units and the developing hopper. Color electrophotographic equipment. 2. The rotation direction of each image forming unit is such that each image forming unit passes through the image forming position in the order of a developing hopper, a passage, and a waste toner box of each image forming unit. The color electrophotographic apparatus according to claim 1. 3. An inner wall of the waste toner box is inclined so that the toner in the waste toner box moves to the passage by gravity during rotation of the image forming unit. 3. The color electrophotographic apparatus according to 2. 4. A plurality of slopes are formed in an inner wall of the waste toner box in a zigzag manner such that toner in the waste toner box moves to the passage by gravity during rotation of the image forming unit, 3. Each of the inclines is inclined toward the passage with the apex opposite to the passage as a vertex.
2. The color electrophotographic apparatus according to 1. 5. A helical shape or a screw shape in which both ends are supported by the waste toner box and have a weight, so that the both ends rotate relative to the image forming unit whose posture does not change even when the image forming unit rotates. The color electrophotographic apparatus according to claim 1, further comprising a stirring member formed with the toner, wherein the toner in the waste toner box is transferred to the passage by a relative rotation of the stirring member. 6. The color electrophotographic apparatus according to claim 5, wherein the spiral shape is formed by processing a linear material. 7. The color electrophotographic apparatus according to claim 1, wherein the passages are formed at both ends of the image forming unit in a rotation axis direction. 8. A central portion in the rotation axis direction of the image forming unit so that toner in the waste toner box moves to a path formed at both ends by gravity during rotation of the image forming unit. The inclination to each passage with the top as
8. A waste toner box provided on an inner wall of the waste toner box.
2. The color electrophotographic apparatus according to 1. 9. A plurality of inclined walls on the inner wall of the waste toner box so that the toner in the waste toner box moves to respective passages formed at both ends by gravity during rotation of the image forming unit. Are formed in a zigzag shape, and each slope on the right side is inclined to the right passage side with the central part side as an apex, and each slope on the left side is the central part side with respect to the central part in the rotation axis direction of the image forming unit. The color electrophotographic apparatus according to claim 7, wherein the color electrophotographic apparatus is inclined to the left side of the passage with a top as a top. 10. A helical shape or a screw shape in which both ends are supported by the waste toner box and have weights, so that the attitude relative to the image forming unit does not change even when the image forming unit is rotated. Is formed, and a stirring member having a different direction of the helical shape or the screw shape is provided around a central portion in the direction of the rotation axis. By relative rotation of the stirring member, the toner in the waste toner box is The color electrophotographic apparatus according to claim 7, which is transferred to each passage. 11. The color electrophotographic apparatus according to claim 7, wherein said spiral shape is formed by processing a linear material. 12. When the gravity acts on the passage in a direction in which the toner moves from the developing hopper side to the waste toner box side, the passage is closed, and the toner is moved from the waste toner box side to the developing hopper side. 8. The color electrophotographic apparatus according to claim 1, further comprising an on-off valve that opens the passage when gravity acts in a direction in which the color image moves. 13. The color electrophotographic apparatus according to claim 12, wherein the on-off valve is fixed to the passage by a hinge, and the on-off valve opens and closes the passage with a rotation shaft of the hinge as a fulcrum. 14. The method according to claim 1, wherein the order of toners of each color to be transferred onto the transfer material is from the one having the highest light transmittance.
The color electrophotographic apparatus according to any one of the above items. 15. The toner color is four colors of yellow, magenta, cyan and black, and the order of each color toner to be transferred to the transfer material is yellow, magenta, cyan and black, or yellow, cyan, magenta and black. 15. The color electrophotographic apparatus according to claim 14, wherein the order is an order.