JPS6018298B2 - Micro gap maintenance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for maintaining a constant minute gap between a rotating cylindrical body and a specific member.

One device equipped with such a device includes a rotating donor drum that uniformly carries powder toner on its outer circumferential surface, and a recording device that faces the outer circumferential surface of the donor drum with a predetermined small gap therebetween. A direct recording device is known that has an electrode and records an image on a recording sheet passing through the gap by applying a signal corresponding to graphic information to the recording electrode. In such a direct recording device, in order to obtain a good and stable recorded image, it is required that the gap between the outer peripheral surface of the donor drum and the recording electrode be kept substantially constant. This is because if the gap is smaller than a predetermined value, the recording sheet will come into contact with the toner on the donor drum, causing background stains, and if the gap is larger than a predetermined value, electrical loss will increase and toner suction will be reduced. This is because there will be situations where something is not done. Furthermore, if the voids change periodically or intermittently, shading occurs in the recorded image, degrading the quality of the image. In order to deal with this, it has been conventional practice to attach a spacer member such as a roller to the recording electrode and bring it into contact with the outer circumferential surface of the donor drum to maintain the gap with the outer circumferential surface of the donor drum as a reference. .

In this case, if there is no foreign matter such as powder toner in the contact area between the spacer member and the donor drum, the gap will always be kept constant. However, in the direct recording device as described above, Since the donor drum carries powder toner over its entire outer peripheral surface, the powder toner is likely to scatter and adhere to the contact area between the spacing member and the donor drum. It is in. When toner adheres to the contact surface between the base member and the donor drum, the toner is removed by the pressing force between the base member and the donor drum.
adheres to the substrate member or the outer surface of the donor drum. In this state, the surface of the spacing member or the donor drum becomes uneven, and a perfect cylindrical body cannot be obtained, especially on the outer circumferential surface of the donor drum, making it impossible to maintain the gap at a constant value, and the outer circumferential surface of the donor drum This may cause problems such as scratches. In view of the above-mentioned problems in conventional direct recording devices, the present invention provides an improved microgap maintaining device configured to prevent powder toner from adhering to the contact area between the spacing member and the donor drum. is intended to provide.

The object of the present invention is to provide a rotating cylindrical body, a specific member disposed facing the outer circumferential surface of the cylindrical body parallel to the cylindrical body, and a member supported by the specific member and on the outer circumferential surface of the cylindrical body. In the apparatus, the cylindrical body has both ends of its outer circumferential surface serving as guide surfaces for the smoothing member, and the device maintains a predetermined gap between the outer circumferential surface and the specific member; The guide surface is separated from the outer circumferential surface of the central portion via an annular groove, and a foreign matter removing element is slidably contacted on the guide surface on the advancing side in the rotational direction of the cylindrical body from the contact portion with the spacing member. This is achieved by a microgap maintaining device characterized by the following.

According to the present invention, by providing the annular groove, foreign matter such as toner is prevented from entering the guide surface, and in the event that foreign matter such as toner adheres to the guide surface. However, it is removed by the foreign matter removal element before the contact part with the smoother member, so that the contact part between the smoother member and the guide surface of the cylindrical body is always kept clean, and the gap is kept at a constant value. It becomes like this.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is directly applied to a recording device will be described in detail below with reference to the accompanying drawings.

Prior to explaining the present invention, the general structure of a direct recording device will first be explained using FIG. In Fig. 1, the reference numeral 1 indicates a donor drum as a rotating cylindrical body, and in the upper part of the donor drum, there is a part facing the outer circumferential surface of the donor drum with a predetermined small gap 3 therebetween. A recording electrode 2 is provided as a specific member for this purpose. The donor drum 1 has a layer of a magnetic material such as nickel on the outer circumferential surface of a non-magnetic cylindrical body made of, for example, aluminum or brass, and the outer circumferential surface is processed to have fine irregularities. The recording electrode 2 extends along one generatrix at the top of the donor drum 1 in the figure, and is embedded with a large number of needle-like electrodes aligned along the generatrix direction, and selectively outputs signals according to calligraphic information. It is now being applied to A toner container 6, which is equipped with a toner replenishing device 4 and contains a powdery conductive magnetic toner 5, is disposed below the donor drum.

A non-magnetic sleeve element 7 is disposed inside the toner container 6 with a predetermined small gap from the outer peripheral surface of the donor drum 1 and rotates about its own central axis.
is installed. One magnetic pole is placed inside the sleeve element 7 and connected to the donor drum 1 across the sleeve element 7.
A magnet element 8 is disposed facing the outer peripheral surface of the donor drum 1 , and a magnet element 9 facing the magnet element 8 is disposed inside the donor drum 1 . Further, on the advancing side in the rotational direction of the donor drum from the part where the magnet element 9 is disposed, there are magnet elements 10 facing each other on the outside and inside of the donor drum.
11 are arranged. A recording paper 12 is passed through the gap 3 between the donor drum 1 and the recording electrode 2,
The recording paper 12 is conveyed in the direction of the arrow in such a manner that it is in contact with the tip of the recording electrode 2.

The toner 5 in the toner container 6 is transported by a sleeve element 7 rotating in the direction of the arrow and a magnet element 8 disposed inside the sleeve element 7.
The sleeve element 7 is transferred toward the outer circumferential surface of the donor drum while being attached to the outer circumferential surface of the sleeve element 7. This toner is transferred from the surface of the sleeve element 7 to the outer peripheral surface of the donor drum by the magnetic element 9, held on the outer peripheral surface by the residual magnetism of the donor drum 1, and transferred as the donor drum rotates. As the donor drum rotates, the toner held on the outer peripheral surface of the donor drum is brought between the magnet elements 10 and 11, and the toner that has been adhering to the outer peripheral surface of the donor drum in a disordered manner is moved by the lines of magnetic force of the magnet elements 10 and 11. They line up along the line and form a so-called tower. This tower is recording paper 12
It is non-contact. The donor drum is rotated in the direction indicated by the arrow in the same direction as the conveying direction of the recording paper 12 at a circumferential speed equal to or greater than the conveying speed of the recording paper. In this state, when a signal corresponding to calligraphic information is applied to the recording electrode 2, in the gap 3, a local electric field is generated that penetrates the recording paper 12 in the thickness direction according to the signal voltage. Due to the action of this electric field, a charge is injected into the toner adhering to the outer peripheral surface of the donor drum by electrostatic induction, and the interaction between this charge and the self-electric field causes the donor to be selectively injected according to the applied signal. the recording paper 1
It metastasizes to the surface of 2. In this way, a toner image corresponding to the graphic information is formed on the surface of the recording paper 12, and this toner image is fixed by an appropriate means to become a permanent image. In such a direct recording device, the air gap 3 between the donor drum and the recording electrode 2 must be maintained constant during the recording operation. Next, the microgap maintaining device according to the present invention will be explained using FIGS. 2 to 5.

Figures 2 to 4 show one example of a direct recording device to which the present invention is applied.
Two examples are shown. Of these, FIG. 2 is a front view showing the mounting structure of the donor drum and the recording electrode, FIG. FIG. 3 is a cross-sectional view taken along line W-W in the figure.
In addition, in FIGS. 2 to 4, parts corresponding to those in FIG. 1 are designated by the same reference numerals as in FIG. 1.
The donor drum is rotatably supported by a shaft 22 between left and right side plates 20 and 21. This donor drum 1 has annular grooves la near both left and right ends thereof, and the space between the annular grooves la actually carries the toner.
In the so-called image forming effective area lb, and on the drum side end side of each of the annular grooves la, there is a guide surface lc. The recording electrode 2 is supported between the side plates 20 and 21 by a linear ball bearing device 23 so as to be movable in the vertical direction in the figure, and by a compression coil spring 24 downward in the figure, that is, around the outer periphery of the donor drum 1. A force of imitation is being applied to the person's face. The recording electrode 2 has roller brackets 26 fixedly supported at both ends by screws 25, and each of the roller brackets 26 is connected to a roller 28 by a shaft 27.
It is rotatably supported. The rollers 28 are each pressed against the guide surface lc of the donor drum 1, roll on the guide surface lc as the donor drum rotates, and rotate the donor drum 1 with reference to the outer peripheral surface of the donor drum 1.
The gap between the outer peripheral surface of the recording electrode 2 and the recording electrode 2 is kept constant. As shown in the figure, the roller bracket 26 has a cap shape that covers the roller 28, and the skirt portion 26' on the image forming effective area lb side
is engaged with the circular ring la at a predetermined small interval,
A labyrinth 29 is defined between the annular groove la and the annular groove la. Further, a scraper blade 30 is provided on the advancing side in the rotational direction of the donor drum 1 from the contact portion between the roller 28 and the guide surface lc, and is in sliding contact with the guide surface lc at that position.

The scraper blade 30 may be constructed of rubber or a rubber-like material, as best shown in FIG.
It is sandwiched between two support plates 31 and 32 and fixed with screws 33. Further, the scraper blade has an inclined surface 30' on the advancing side in the direction of rotation of the donor drum, and the scraped toner powder is guided to the inclined surface 30' and removed. With the above configuration, even if the toner in the image forming effective area lb of the donor drum 1 tries to enter the contact area between the guide surface lc and the roller 28, it will not be able to enter the circular groove la and its annular groove. This is blocked by a labyrinth 29 which is constructed in sections. In addition, even if toner passes through that part and adheres to the guide surface lc, it will be removed from the guide surface lc by the scraper blade 3 before the contact part with the roller 28.
More scraped and removed. Therefore, the contact area between the guide surface lc of the donor drum and the roller 28 is always kept clean and free of toner. As a result, the void 3
is kept at a predetermined constant value. FIG. 5 is an enlarged front view of main parts showing another embodiment of a direct recording apparatus to which the present invention is applied.

In FIG. 5, parts corresponding to those in FIGS. 1 to 4 are designated by the same reference numerals as those in FIGS. 1 to 4. In this embodiment, the scraper blade 30
The scraping edge 30'' is inclined with respect to the generatrix of the donor drum 1.As shown in the figure, the side edge side of the donor drum 1 is closer to the advancing side in the rotational direction of the donor drum than the center side. Therefore, in this case, the toner scraped by the scraper blade 301 is guided by the slope of the scraping green 30'' and removed toward the side edge of the donor drum 1. , toner is prevented from remaining in the contact area between the donor drum and the scraper blade 30. In the embodiment described above,
Although the toner adhering to the guide surface lc was removed using a scraper blade, the present invention is not limited to this. Toner removal may be performed using cleaning rollers 34 and 35 as shown in FIG. Good too. In this case, the cleaning roller 34 may be made of rubber or foamed resin, and the cleaning roller 35 may contain a volatile liquid such as alcohol or isopa.
Although the present invention has been described in detail with respect to specific embodiments above, it is clear to those skilled in the art that the present invention is not limited to these and that various embodiments are possible within the scope of the present invention. Probably.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the general structure of a direct recording device;
FIG. 2 is a front view showing the attachment structure of the donor drum and recording electrodes of the direct recording device according to the present invention, FIG. 3 is a vertical sectional view showing an enlarged main part thereof, and FIG. 4 is a line taken along the line of FIG. 3. W-N
FIG. 5 is an enlarged front view of another embodiment of a direct recording device to which the microgap maintaining device of the present invention is applied, and FIG. 6 is a direct view to which the present invention is applied. FIG. 7 is a sectional view showing still another embodiment of the recording device. 1... Donor drum, la... Annular groove, l
b... Image forming effective area, lc... Guide surface, 2... Recording electrode, 3... Void,
4... Toner supply device, 5... Toner, 6... Toner container, 7... Sleeve element, 8, 9, 11... ...Magnetic element, 12
... Recording paper, 20, 21 ... Side plate, 2
2... Shaft, 23... Linear ball bearing device, 24... Compression coil spring, 25...
...Screw, 26...Roller bracket, 27...Shaft, 28
...Roller, 29...Labyrinth, 30...Scraper blade, 31, 32...Support plate, 33...Screw, 34
, 35...Cleaning loaf. False I figure Rare 2 figure Rare 3 figure Rare 4 figure Older sister 5 figure False 6 figure

Claims (1)

[Claims] 1. A rotating cylindrical body, a specific member disposed facing the outer circumferential surface of the cylindrical body in parallel with the cylindrical body, and a spacer member supported by the specific member and in contact with the outer circumferential surface of the cylindrical body. In the apparatus for maintaining a predetermined gap between the outer circumferential surface and a specific member, the cylindrical body has both ends of the outer circumferential surface serving as guide surfaces for the spacer member, and the guide surfaces are circular. A microgap that is separated from the outer circumferential surface of the central portion via a groove, and is formed by sliding a foreign matter removing element on the guide surface on the advancing side in the rotational direction of the cylindrical body from the contact portion with the spacer member. maintenance equipment.