JP2000172047A - Color electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent soil of the inside of a device due to toner spillage by storing in a developing part toner separated from a developing roller and also receiving by a toner receiving member toner spilling from the opening of an image forming unit rotatively moving. SOLUTION: An image forming position includes an exposure position where a laser beam 10 strikes a photoreceptor 2 and a transfer position where the photoreceptor 2 and a transfer drum 34 are in contact with each other. In the position, each image forming unit performs an image forming operation. Because non-magnetic one-component toner is used, magnetic force cannot be used as force with which toner is held on each developing roller 23, and toner that is small in amount of charges sticks to the developing roller 23 with weak electrostatic force. As the developing roller 23 rotates, toner accumulates below the developing roller 23, so that when an image forming unit group 8 rotatively moves, the toner accumulating in each image forming unit spills out. The toner falling down in the direction of gravity is received by a toner spillage receptacle 46 as a toner receiving member, thereby preventing it from scattering in an electrophtographic device.

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, and an electrophotographic photosensitive member and a developing device used for the apparatus.

[0002]

2. Description of the Related Art As an example of a conventional color electrophotographic apparatus,
The configuration will be described with reference to JP-A-7-36246. FIG. 12 is an overall configuration diagram of the conventional color electrophotographic apparatus, and the maximum print size is an A4 size apparatus. In this conventional example, an intermediate transfer belt 102 is used as an image synthesis transfer unit. Intermediate transfer belt unit 10
1 is an intermediate transfer belt 102, a first transfer roller 103,
The color image is superimposed on the belt 102 by including the second transfer roller 104, the cleaner roller 105, the waste toner reservoir 106, and the like. In the center of the printer, four fan-shaped image forming units 107Bk, 107Y, 107M, and 107 having the same size for each color of black, yellow, magenta, and cyan.
C constitutes the image forming unit group 108 and is arranged in an annular shape as shown in the figure.

When the image forming unit 107 is properly mounted in the printer, mechanical drive systems and electric circuit systems on both the image forming unit side and the printer main body side are connected via a mutual coupling member. Mechanically and electrically integrated. Image forming unit 10 arranged in an annular shape
7Bk, 107Y, 107M, and 107C are supported by a support, are driven by a moving motor as a whole, and are configured to be rotatable about a fixed, non-rotating cylindrical shaft 109. At the time of image formation, each image forming unit rotates and moves the image forming position 11 facing the first transfer roller 103 that sequentially supports the intermediate transfer belt 102.
0 can be located. The image forming position 110 is also an exposure position by the laser beam 111.

Reference numeral 112 denotes a laser exposure device disposed on the lower side of the printer. 113 is an optical path window, 114 is a mirror, 115 is an exposure window of the image forming unit 107Bk, 11
Reference numeral 6 denotes a developing device disposed on the upper side in the image forming unit;
17 is a cleaner disposed on the lower side, and 118 is a diameter 3
0 mm photosensitive drum. 119 is a third transfer roller, and 120 is a fixing machine. This is disclosed in JP-A-7-362.
This is the configuration of Japanese Patent Publication No. 46-46.

[0005] This conventional color electrophotographic apparatus is modified, and a developing device is provided with a one-component developing device for flying and developing toner, that is, a so-called jumping developing device. An apparatus using a transfer drum around which the recording medium was wound was constructed. FIG. 13 shows the configuration.
Reference numeral 1 denotes a transfer drum having a diameter of 120 mm. Transfer drum 1
After electrostatically adsorbing paper on the surface and winding it, photoreceptor 2
The upper toner image is directly transferred to paper by applying a bias voltage, and a color toner image is synthesized.

The transfer drum 1 includes a surface elastic layer 3, a cleaner 4, a paper suction roller 5, a paper separation charger 6, and the like. At the center of the printer, four fan-shaped image forming units 7Y, 7M, 7C, and 7Bk, each of yellow, magenta, cyan, and black, form an image forming unit group 8, and are arranged in an annular shape as shown in the figure. I have. Reference numeral 9 denotes a laser exposure device disposed on the upper side in the printer. The laser beam 10 is applied to the image forming units 7Y and 7Y.
M, through a light path window 11 formed through a window, opened through a part of the shaft 12 and incident on a fixed mirror 13 in the shaft 12, reflected and formed at an image forming position 14. The light enters the image forming unit 7Y from the exposure window 15 of the unit 7Y, and passes through the optical path between the cleaner 16 and the developing unit 17 disposed above and below the image forming unit, thereby exposing the left side surface of the photosensitive drum 2 to light. And is scanned and exposed in the generatrix direction. The toner image formed on the photoconductor 2 is transferred to paper on the transfer drum 1. Next, the image forming unit group 8 is rotated by 80 ° in the direction of arrow Q, and the magenta image forming unit 7M is moved.
Is replaced with the image forming position 14. By performing the same operation as the yellow step, the magenta toner image is transferred onto the paper on the transfer drum 1 so as to overlap the yellow toner image. The same operation is further performed using cyan and black image forming units. After the full-color image is completed on the paper, the paper is separated from the transfer drum 1 by the separation charger 6 and finally fixed by the fixing device 18.

[0007]

In the conventional apparatus shown in FIG. 13, the diameter of the photosensitive member was 30 mm, and the diameter of the transfer drum, which is an image synthesizing transfer section, was 120 mm, which is four times the diameter of the photosensitive member.
The diameter of the developing roller of the developing device was 16 mm. This device has the following problems. In the apparatus shown in FIG. 13, since the one-component developing unit is swung upside down with the rotation of the image forming unit group, the non-magnetic toner accumulated inside the image forming unit easily spills down and contaminates the inside of the apparatus. .

An object of the present invention is to provide a color electrophotographic apparatus in which a developing device using a one-component non-magnetic toner is configured as an image forming unit, and the entire image forming unit group is rotated and moved inside a printer. To prevent contamination of the interior.

[0009]

In order to achieve the above object, the present invention has the following arrangement. The invention according to claim 1 is an image comprising a developing device for storing a non-magnetic one-component toner, forming a thin layer of the non-magnetic toner on a developing roller, and causing the non-magnetic toner to fly by an alternating electric field for development. A forming unit and the image forming unit, wherein the image forming unit is located at a position where the opening of the image forming unit faces upward, and at a position downstream of the moving direction of the image forming unit with respect to the position; An image forming position for forming a toner image on
An image forming unit group that is rotatable and movable so as to be able to take a position downstream of the image forming position in the moving direction of the image forming unit and the opening is directed downward, and gravity of the image forming unit group A toner receiving member which is disposed in the lower direction and located downstream of the image forming unit located at the image forming position in the moving direction, and is provided so as to face the image forming unit at the position where the opening faces downward. , And
At the image forming position, the toner detached from the developing roller is accommodated in the developing device, and spills out of the opening in the image forming unit that rotates to the downstream in the moving direction from the image forming position. A color electrophotographic apparatus characterized in that toner is received by a toner receiving member.

According to a sixth aspect of the present invention, there is provided a developing method for storing a non-magnetic one-component toner, forming a thin layer of the non-magnetic toner on a developing roller, and causing the non-magnetic toner to fly by an alternating electric field for development. An image forming unit provided with an image forming unit and the image forming unit, wherein the image forming unit is located at a position where an opening of the image forming unit faces upward, and at a position downstream of the image forming unit with respect to the moving direction with respect to the position. Rotating so as to take an image forming position where a toner image is formed on the photoconductor, and a position downstream of the image forming position in the moving direction of the image forming unit and the opening is directed downward. A movable electroforming unit group, wherein the method includes a step of recovering the toner falling from the inside of the image forming unit to the outside, wherein the toner is separated from the developing roller at the image forming position. Storing the toner in the developing device, and the image forming unit rotatably moving downstream from the image forming position in the rotation direction. Receiving toner spilled by a toner receiving member disposed below the image forming unit group in the direction of gravity;
And a toner collection method for a color electrophotographic apparatus.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction and operation of a color electrophotographic apparatus according to one embodiment of the present invention will be described below with reference to the drawings.

The configuration of the color electrophotographic apparatus of the present invention will be described in detail with reference to FIG. 13 differs from FIG. 13 in the configuration of the transfer drum and the developing device. 2 is a photoreceptor, 3 is a surface elastic layer of the transfer drum 34, 4 is a cleaner, 5 is a paper suction roller,
6 is a separation charger, 7 is an image forming unit, 8 is an image forming unit group, 9 is a laser exposure device, 10 is a laser beam, 11 is an optical path window, 12 is a shaft, 13 is a mirror, 14 is an image forming position, 15 Is an exposure window, 16 is a cleaner, 17 is a developing device, 1
8 is a fixing machine, and 19 is paper. Here, in the present invention, in order to solve the above-described problem of the conventional example, the diameters of the photoconductor 2 and the transfer drum 34 are different, and are 24 mm and 144 mm, respectively.
mm, and the diameter of the photosensitive member 2 is 1/6 of the diameter of the transfer drum.
And has an integer ratio relationship of 1: 6.

Here, the image forming position 14 refers to the laser light 1
0 indicates a position including an exposure position corresponding to the photoconductor 2 and a transfer position where the photoconductor 2 and the transfer drum 34 are in contact with each other, and is a position where the image forming unit performs the temporal image forming operation. That is, in FIG. 1, it is the position where the yellow image forming unit 7Y exists.

An image forming unit 7 arranged in an annular shape
Y, 7M, 7C, and 7Bk are supported by a support (not shown), and are driven by moving means as a whole of the image forming unit group 8, and are rotated around a fixed and non-rotating cylindrical shaft 12 in an arrow direction Q. It is configured to be rotatable.

FIG. 2A shows a black image forming unit 7Bk,
(B) Image forming unit 7 for yellow, magenta and cyan
Y, 7M and 7C are shown. Each image forming unit differs only in the size of the developer and the developing device contained therein. Since the other components are the same, the image forming unit 7Bk for black will be described for simplicity of description, and the other colors will be omitted. In addition, the same reference numerals are assigned to the same parts for each color, and when it is necessary to distinguish the configuration of each color, a letter indicating each color is added to the reference numeral.

FIG. 2 shows the arrangement of the developing devices in the image forming position, and the upper part of the drawing is shown as the upper part in the direction of gravity. In FIG. 2A, reference numeral 10 denotes the laser beam also shown in FIG. 1, and reference numeral 2 denotes a diameter 2 mainly composed of a polycarbonate-based binder resin using phthalocyanine as a photosensitive material.
4 mm organic photoreceptor, 20 is a corona charger for negatively charging the photoreceptor, 21 is a grid for controlling the charging potential of the photoreceptor constant, 15 is an opening of the image forming unit through which laser light enters the image forming unit. Exposure window 17Bk is a black developing device. The developing device 17 includes a toner hopper 22, a developing roller 23 having a diameter of 12 mm as a toner carrier, a supply roller 24 that frictionally charges toner and supplies the toner to the developing roller 23, a blade 25 made of urethane rubber, and the like. Therefore, the diameter of the developing roller 23 as a toner carrier is １ ／ of the diameter of the photoconductor 2. In the toner hopper 22,
The toner contains black toner 26Bk in which a black pigment is dispersed in a polyester resin.

The black toner is triboelectrically charged by the supply roller 24, formed into a thin layer of about 30 μm by the blade 25, and then carried on the surface of the developing roller 23 to form the photosensitive members 2 and 2.
The image is developed with a gap of 00 μm. At this time, as a developing bias, 750 V0-p (peak-to-peak 1.
5 kV) AC voltage (frequency 3 kHz) was applied. 1
Reference numeral 6 denotes a cleaner for cleaning the toner remaining on the surface of the photoconductor 2 after the transfer, and includes a cleaning blade 28 made of rubber and a waste toner reservoir 30 for storing the waste toner 29. The photoreceptor 2 rotates in a direction indicated by an arrow at a peripheral speed of 100 mm / s.
Reference numeral 3 also rotates in the same traveling direction as the photosensitive member 2 at a peripheral speed of 100 mm / s. A dotted circle 31 indicates a maximum outer circumference circle when the image forming unit group 8 in FIG. 1 rotates and is also a movement locus of the outermost circumference of the photoconductor 2. 32 is a blade protection member of the present invention described later. An agitator 33 supplies the toner 26 from the toner hopper 22 to the supply roller 24.

FIG. 2A shows an image forming unit for yellow, magenta, and cyan.
This is different from the above-described black developing device 17Bk. The black image forming unit 7Bk in FIG. 2A has a substantially fan-shaped shape, and the fan-shaped spread angle θ is 120 °. The breakdown is cleaner part 1
6 is about 30 ° and the developing unit 17Bk is about 90 °. On the other hand, the yellow, magenta, and cyan image forming unit shown in FIG. 2A has a fan-shaped spread angle θ of 80 °, the cleaner unit 16 has the same angle of approximately 30 °, and the developing unit 17 has the approximately 5 ° angle.
0 °. Accordingly, the capacity of the black toner hopper is 1.8 times the capacity of the hoppers of the other three colors. In general, the amount of black toner used is larger than that of the other three colors, but this configuration can reduce the frequency of replacement of the black image forming unit.

Returning to FIG. In the printer of FIG. 1, the image forming unit group 8 is rotated and moved, and the yellow image forming unit 7Y is positioned and fixed at the image forming position 14.
The paper 19 sent from the paper cassette is wound around the transfer drum 34 by the paper suction roller 5 in advance.

The structure of the transfer drum 34 which is an image synthesizing transfer section used in the present invention will be described with reference to FIG. The transfer drum 34 has a conductive foam elastic layer 36 having a thickness of about 5 mm formed on an aluminum drum base 35 to which a transfer bias voltage having a diameter of 139 mm is applied.
0 μm polyvinylidene fluoride film 37 is coated,
The maximum diameter is 144 mm. Therefore, the developing roller, the photoconductor, and the transfer drum are set to an integer ratio of 1: 2: 6. The transfer drum 34 has a length of 10
A recess 38 having a depth of 0 mm and a depth of 4 mm is formed.

In the present invention, the concave portion 38 is formed in a part of the cylindrical image synthesizing transfer portion, and when the image forming unit group rotates, the concave portion faces the image forming position, and the outer peripheral length of the concave portion is formed. However, because the configuration is longer than the distance from the position at which the photoconductor that rotates at least and the outermost peripheral portion of the image synthesis transfer unit starts contacting to the position of the photoconductor at the image forming position,
The occurrence of scratches on the photoreceptor surface can be prevented.

A paper 19 is wound around the surface of the transfer drum 34, and a color toner image is sequentially transferred and superimposed on the paper 19 to form a full-color image. Thereafter, the paper 19 is separated from the transfer drum 34 and fixed. . FIG. 3A shows an intermediate transfer drum 39 for directly transferring a toner image, and such an intermediate transfer drum can be applied to the present invention. The intermediate transfer drum 39 transfers a toner image to a high-resistance layer on the surface by applying a transfer bias, forms a full-color toner image on the intermediate transfer drum surface 39, and then transfers the toner image to the paper 19 by a transfer unit 40. This is a configuration for transferring an image.

Referring back to FIG. 1, the full-color image forming process will be described. The printer of FIG. 1 first performs a yellow image forming process. The operation of the image forming unit 7Y will be described with reference to FIG. The photoconductor 2 was charged to -450 V by the charger 20 to which a voltage of -450 V was applied to the grid 21. The photosensitive member 2 was irradiated with a laser beam 10 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -50V. The photoreceptor 2 was developed by the developing roller 23 carrying the one-component yellow toner 26Y. At this time -450
When passing through the surface of the photoconductor 2 on which the electrostatic latent image has been written by being charged to V, the developing roller 23 is supplied with -300
750V0-p (Peak-to-
An AC voltage (frequency: 3 kHz) with a peak of 1.5 kV was applied. As a result, a yellow-positive yellow toner image was formed only on the image area on the photoconductor 2. At this time, the image forming unit group 8 is at the position shown in FIG. 1, and the yellow image forming unit 7Y is at the image forming position 14 as shown. During this image forming process, the photoconductor 2 and the paper 19 on the transfer drum 34 are
Is in contact with In the image forming process of the image forming unit described above, the image was formed by the yellow toner.

Immediately after all the yellow toner images have been transferred, the entire image forming unit group 8 is driven by the moving motor and rotated exactly 80 ° in the direction of arrow Q in FIG. 1 to move the image forming unit 7M to the image forming position. It stopped at the position where it reached 14. When the rotation of the image forming unit group 8 is completed and the image forming unit 7M reaches the image forming position 14 and the rotation of the photoconductor 2 reaches a constant speed, the laser exposure device 9 receives the magenta signal again as before. The image forming unit 7M was irradiated with signal light to form and transfer a magenta toner image. By this time, the transfer drum 34 has made one rotation, the signal light of magenta and the timing of writing are controlled, and the magenta toner image previously transferred is superimposed so that the next magenta toner image is positionally matched. Was.

Again, the entire image forming unit group 8 was driven by the moving motor and rotated by 80 ° in the direction of arrow Q, and stopped at the position where the image forming unit 7C reached the image forming position 14. The same operation as for yellow magenta was performed for cyan.

Finally, the entire image forming unit group 8 is rotated by 120 ° in the direction of arrow Q to replace the image forming unit 7Bk with the image forming position 14 and form an image with black toner. The four color toner images were superimposed on the paper on the transfer drum 34 in a position-matching manner, and a full-color image was formed. The toner image transferred to the paper was fixed by the fixing device 18.

The above is the description of the configuration and operation of the representative embodiment of the present invention.

Next, the operation and effect of the present invention will be described with reference to FIGS.

FIG. 4 is a view for explaining the effect of the present invention in which the diameter of the photosensitive member 2 is set to an integral ratio of 1/5 or less of the diameter of the cylindrical image transfer section 34. In the above embodiment, a drum having a diameter of 24 mm was used for the photosensitive member 2, and a drum having a diameter of 144 mm, which was six times as large as the transfer drum 34, was used at this time. The developing method used in the present invention is a so-called jumping developing method in which the toner is brought into contact with the photoreceptor in a non-contact manner and is developed by flying in a space. In this developing method, the charge amount of the toner is set to -3 to 5 μm so that the toner can easily fly in space.
C / g and -10 to 30 of the conventional two-component developer toner.
It is adjusted very low compared to μC / g. When such toner is transferred from the photoreceptor to the transfer drum, a phenomenon has occurred in which the toner image is easily scattered and an unclear image is formed. In response to this phenomenon, the inventors have found that the smaller the diameter of the photoreceptor, the more the scattering of the toner can be reduced.

The reason will be discussed with reference to FIG. FIG.
(A) Large-diameter photoreceptor 2 having a diameter of 40 mm or more and 144 mm
3 shows the contact state between the photosensitive drum 2 and the transfer drum 34 when the transfer drum 34 is used. FIG. 5A shows the case where a small-diameter photosensitive member having a diameter of 24 mm is used. In both figures, the toner image 26 on the photoreceptor is
Is transferred to the image. + 1k for transfer drum
A voltage of V is applied, and the negatively charged toner 26 is transferred to the surface of the paper 19. At this time, the low-charged toner used in the present invention is very easy to fly electrostatically for the purpose of flying development.
Flying starts from a gap of mm (distance number 41 in the figure), and the image is transferred. At this time, even if the image is sharp on the photoreceptor, the toner scatters on the paper 19 and is blurred.

The smaller the area where the gap 41 is 0.7 mm or less, that is, the area 42 in FIG. Figure (A)
Needless to say, 43 in FIG. 13A becomes narrower than 42 in FIG. In an experiment, in the transfer process using such a toner having a low charge amount, the diameter of the photoconductor is set to １ ／ of the diameter of the transfer drum.
It has been determined that the following can be achieved at a resolution of 400 dpi so that flying dust can not be visually recognized. In addition, 600d
In order to obtain a high-resolution image of pi or more, it has been determined that it is more desirable to set an integer ratio of 1/6 or less. Examples of the configuration that achieves the effects of the present invention include the following combinations of the diameters of the transfer drum and the photoconductor. Transfer drum diameter: 280 mm, photoconductor diameter: 40 mm, (1/7) Transfer drum diameter: 240 mm, photoconductor diameter: 40 mm, (1/6) Transfer drum diameter: 210 mm, photoconductor diameter: 30 mm, (1/7) ) Transfer drum diameter: 180 mm, photoconductor diameter: 30 mm, (1/6) transfer drum diameter: 150 mm, photoconductor diameter: 30 mm, (1/5) transfer drum diameter: 168 mm, photoconductor diameter: 24 mm, (1/6) 7) Transfer drum diameter: 144 mm, photoconductor diameter: 24 mm, (1/6)

Conversely, combinations in which the effect of preventing toner scattering is not so recognized are as follows. Transfer drum diameter: 180 mm, Photoconductor diameter: 60 mm, (1/3) Transfer drum diameter: 160 mm, Photoconductor diameter: 40 mm, (1/4) Transfer drum diameter: 120 mm, Photoconductor diameter: 30 mm, (1/4) )

Next, the operation of the second configuration of the present invention will be described with reference to FIG. In the present invention, a developing device having a configuration in which a thin layer of non-magnetic toner is formed on a toner carrier, that is, a developing roller 23, and is rotated in substantially the same speed and in the same traveling direction as the photoconductor 2 to perform development. With this configuration, a feature of the present invention is that the outer peripheral length of the developing roller 23 is an integer fraction of the outer peripheral length of the photoconductor 2 and the outer peripheral length of the developing roller 23 is an integral number of the outer peripheral length of the transfer drum 31. 1

In the present invention, the outer peripheral length is defined. However, when an intermediate transfer belt is used, the expression of the outer peripheral length is appropriate, and when a photosensitive drum or a transfer drum is used, it is synonymous with the diameter.

The constituent requirements of the present invention are the following four conditions. (1) The developing roller rotates with the photoconductor at substantially the same speed in the same traveling direction. (2) The outer peripheral length between the developing roller and the photoconductor has an integer ratio relationship. (3) The photoconductor and the transfer drum rotate at substantially the same speed in the same traveling direction. (4) The outer peripheral lengths of the photoconductor and the transfer drum have an integer ratio relationship.

Here, if the rotation unevenness cycle of the developing roller is shifted for each color, the hue difference of the composite color becomes large when different colors are superimposed. On the other hand, when the rotation unevenness periods of the developing rollers of the respective colors are made to coincide with each other and superimposed, they appear on the image as color density changes instead of hue differences. In a business color print in which the difference in hue often has a meaning of display, the hue difference is less preferable than the color density unevenness. The developing device of the present invention has a configuration in which a rubber blade is pressed and fixed on a developing roller.
5 pressing marks appear. Further, if left for a long time under high temperature and high humidity, the used rubber blade 25 may be deformed. In such a case, development unevenness occurs in the rotation cycle of the development roller. However, even in such a case, since the generated horizontal streak cycle is synchronized with the photoconductor rotation cycle and the transfer drum rotation cycle for each color, the hue does not differ for each print even for a plurality of puddings. It does not give a different impression to the obtained data and does not give any visual discomfort. In the present invention, such hue unevenness does not appear.

The integer ratio relationship between the outer peripheral lengths of the developing roller, the photosensitive member, and the transfer drum is not limited to a color electrophotographic apparatus having a fan-shaped image forming unit as shown in FIG. Image forming unit 7Y, M, C, Bk
It is needless to say that the present invention can also be applied to a color electrophotographic apparatus using the same.

Further, as another effect of the present invention, the deformation of the rubber blade under such high temperature and high humidity can be prevented, and the occurrence of image unevenness can be prevented. This effect is shown in FIG.
This will be described with reference to FIG. In the present invention, the developing device 17 has a configuration in which a thin layer of non-magnetic toner is formed on a toner carrier by a rubber elastic blade 25. At this time,
The blade protection member reduces the supply pressure of the toner from inside the toner hopper to the developing roller in the lateral direction of gravity during image formation of the image forming unit, thereby preventing the elastic blade from being pressed. At the same time, when the image forming unit does not form an image, this member reduces the pressure of the toner in the toner hopper on the developing roller in the direction of gravity, thereby preventing the elastic blade from being pressed.

In the present invention, as shown in FIG. 8, the printer does not operate in a state where the vertical relationship of the developing unit 17 is constant in the printer apparatus, and the states (A) to (D) are repeated to form a full-color image. Here, attention is paid to the position of the cyan image forming unit 7C. The start of full-color image formation starts from the yellow image formation unit 7Y and is in the state of FIG. Thereafter, the process proceeds to (a) and (c), and finally, the black image forming unit 7B
The process ends at the position (d) in the image formation state of k. Generally,
Even in the case of a full-color printer, black single-color printing is frequently used, and there are many stops in this state (d). If the apparatus is left for a long time under high temperature and high humidity, the cyan image forming unit 7C is liable to cause a trouble inside the developing device. The problem of FIG. 8D will be described with reference to FIG. FIG. 9 is an enlarged view of the state of the cyan image forming unit 7C of FIG. In this state, the toner 26 in the toner hopper is
The entire weight of C is applied to the vicinity of the developing roller 23.
There are problems such as (A) the rubber blade 25 is easily deformed, which causes image unevenness, and (B) the toner near the developing roller tends to aggregate.

Regarding the problem (A), the toner 26 in the toner hopper presses the rubber blade 25 downward in the direction of gravity (in the direction of arrow G), and permanent deformation accompanied by deterioration of urethane rubber is likely to occur under high humidity. . In particular, when the polyester resin is used for the toner, the specific gravity of the styrene acrylic resin is 1.2, which is heavier than 1.05, and the toner is 8 μm
In the case where the fluidity is reduced due to the formation of fine particles below, the blade compression phenomenon becomes a problem. In a monochrome monochrome printer, the toner is designed so as not to press the blade. However, in the present invention, one of the four image forming units must be stored for a long time in the state shown in FIG. Is done.

FIG. 9A shows the toner aggregation phenomenon near the developing roller in FIG. 9B. When the weak aggregate 44 of the toner is generated, the supply of the toner from the toner hopper to the supply roller 24 is hindered in the image forming state of the image forming unit.
Insufficient supply of toner to the developing roller 23 occurs, and in severe cases, image omission may occur.

In order to solve the problems (A) and (B), in the present invention, this problem is solved by adding a constituent member that prevents the weight of the toner from directly hitting the rubber blade in the downward direction of gravity (the direction of arrow G). Was solved. As shown in FIG. 10, since the blade protection member 32 is provided above the blade 25 in the direction of gravity, the toner 2
6 is not directly applied to the blade 25. Accordingly, it is possible to prevent the deformation of the blade and the generation of the toner aggregate due to the compression of the toner.

Further, the blade protection member 32 of the present invention
There is another effect in the operation of the image forming unit in the image forming state. As shown in FIG. 10A, the toner supply pressure (in the direction of arrow P) due to the rotation of the toner supply agitator 33 is not directly applied to the rubber blade 32. Thereby, regulation of the toner layer thickness by the blade 25 is stabilized, and a uniform image can be obtained.

Another operation and effect of the present invention will be described.
The color electrophotographic apparatus of the present invention uses a non-magnetic one-component toner. For this reason, magnetic force cannot be used as the toner carrying force on the developing roller. The low charge toner adheres to the developing roller with a weak electrostatic force. For example, when the yellow image forming unit 7 </ b> Y is used for image formation as shown in FIG. 11, the toner 45 gradually accumulates below the developing roller 23 as the developing roller 23 rotates. In this state, the spilled toner 45 does not spill outside due to the exterior of the image forming unit 7Y. However, when the image forming unit group 8 rotates, the image forming unit 7Y
The spilled toner 45 accumulated in the toner spills out. In particular, according to the present invention, since a large image forming unit group is rotationally moved, not only a large amount of vibration is generated but also the image forming unit is rotationally moved while the vertical position is reversed. Therefore, in the present invention, the falling toner 47 is received by using the spilled toner receiver 46 as the toner receiving member for receiving the dropped toner 47 downward in the direction of gravity so as not to be scattered inside the electrophotographic apparatus.

At this time, the falling toner 47 does not always fall downward in the direction of gravity due to the flow of air accompanying the rotational movement of the image forming unit group 8. This image forming unit group 8
In order to prevent toner scattering due to the rotational movement of
It has been found that when the gap 49 between the side wall 48 of the spilled toner receiver 46 and the image forming unit group 8 of the present invention is set to 2 mm or less, contamination inside the apparatus due to toner can be prevented.

[0046]

According to the present invention, in a color electrophotographic apparatus for moving an entire developing device using a one-component non-magnetic toner in a vertical direction inside a printer, a spilled toner receiver is provided below an image forming unit group. Therefore, contamination in the apparatus can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a color electrophotographic apparatus of the present invention.

FIG. 2 is a configuration diagram illustrating the configuration of an image forming unit of the present invention.

FIG. 3 is a configuration diagram showing a configuration of a transfer drum and an intermediate transfer drum, which are image synthesis transfer units of the present invention.

FIG. 4 is an explanatory diagram illustrating a configuration of the present invention.

FIG. 5 is an explanatory diagram for explaining the effect of the present invention in detail.

FIG. 6 is an explanatory diagram illustrating a configuration of the present invention.

FIG. 7 is a configuration diagram of another embodiment of the present invention.

FIG. 8 is an explanatory view for explaining a problem of the conventional example.

FIG. 9 is an explanatory diagram for explaining the problem of the conventional example in more detail;

FIG. 10 is an explanatory diagram for explaining another effect of the present invention in detail.

FIG. 11 is an explanatory diagram for explaining still another effect of the present invention in detail.

FIG. 12 is a configuration diagram of a conventional color electrophotographic apparatus.

FIG. 13 is a configuration diagram of a color electrophotographic apparatus according to a second conventional example.

[Explanation of symbols]

2 Photoreceptor 7Bk Image forming unit for black 7Y, M, C Image forming unit for yellow, magenta, cyan 8 Image forming unit group 9 Laser exposure device 12 Axis 13 Mirror 16 Cleaner 17 Developing device 32 Blade protection member 34 Transfer drum 46 Spill Toner tray

Claims (6)

[Claims] 1. An image forming unit which contains a non-magnetic one-component toner, forms a thin layer of the non-magnetic toner on a developing roller, and has a developing device for developing the non-magnetic toner by flying by an alternating electric field. And disposing the image forming unit, wherein the image forming unit comprises:
With respect to a position where the opening of the image forming unit faces upward, an image forming position where a toner image is formed on a photoconductor on the downstream side in the moving direction of the image forming unit with respect to the position, and a position relative to the image forming position. Downstream of the moving direction of the image forming unit,
An image forming unit group rotatable so as to be able to take a position where the opening faces downward; and an image forming unit located below the image forming unit group in the direction of gravity and located at the image forming position. A toner receiving member disposed on the downstream side in the movement direction and provided so as to face the image forming unit at a position where the opening faces downward, and the toner separated from the developing roller at the image forming position. And a toner receiving member for receiving the toner spilling outside from the opening in the image forming unit rotating and moving downstream from the image forming position in the moving direction. A color electrophotographic apparatus characterized by the above-mentioned. 2. The color electrophotographic apparatus according to claim 1, wherein the toner receiving member receives the toner dropped from an opening of the image forming unit that rotates. 3. The color electrophotographic apparatus according to claim 1, wherein the toner receiving member has a bottom portion and a pair of side walls along a rotation direction of the image forming unit, and accommodates the toner dropped therein. 4. The color electrophotographic apparatus according to claim 3, wherein a distance between the side walls is shorter than an outer diameter of the image forming unit group. 5. The color electrophotographic apparatus according to claim 3, wherein a gap between a side wall of the toner receiving member and a rotation outer peripheral circle of the image forming unit group is 2 mm or less. 6. An image forming unit containing a non-magnetic one-component toner, forming a thin layer of the non-magnetic toner on a developing roller, and developing the non-magnetic toner by flying by an alternating electric field. And disposing the image forming unit, wherein the image forming unit comprises:
With respect to a position where the opening of the image forming unit faces upward, an image forming position where a toner image is formed on a photoconductor on the downstream side in the moving direction of the image forming unit with respect to the position, and a position relative to the image forming position. Downstream of the moving direction of the image forming unit,
A group of image forming units that are rotatable and movable so as to be able to take a position where the opening faces downward, wherein a method for collecting toner that falls from the inside of the image forming unit to the outside is provided. In the image forming position, a step of accommodating the toner detached from the developing roller in the developing device, and in the image forming unit that is rotated from the image forming position to the downstream in the rotational direction, in the developing device. Receiving the toner contained therein, the toner spilling out from the opening by a toner receiving member disposed below the image forming unit group in the direction of gravity. Toner collection method.