JPH02173766A - Image forming device - Google Patents

Abstract

PURPOSE:To completely erase electric charges and to improve image quality by providing a developer adhering area so that a specified amount of developer may be supplied to the rubbing part of an erasing means and a recording medium. CONSTITUTION:The toner adhering area is provided in an image nondisplay area 12B so that the specified amount of toner may be supplied to the rubbing part of a cleaning member 13 and the recording medium 1. In such a case, the developer adhering to the developer adhering area is supplied to the rubbing part of the erasing member accompanied with the movement of the recording medium 1 and the rubbing part of the erasing member is always kept in a state where it is filled with the developer. Since the contact area of the rubbing part becomes large even if the erasing member consecutively rubs the white image part of the recording medium 1, electrical resistance is made low and the charge generated on the surface of the recording medium in the case of forming an image, the charge given to the developer and other charge generated by the rubbing of the recording medium 1 with the erasing member in the case of erasing the image move through a conductive erasing means 13b to reduce electrostatic charging quantity on the recording medium 1. Thus, the magnetic developer is prevented from adhering to the nonimage part and the high definition image is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus applied to printers, display devices, etc., and in particular to an image forming apparatus that applies a voltage between a plurality of recording electrodes and a recording medium to form a developer. It relates to a device that forms an image by attaching particles of the same to a recording medium.

(Prior Art) As a conventional image forming apparatus of this type, for example,
There is something like the one shown in the figure. That is, conductive toner is conveyed onto the recording electrode 109 by the rotation of the magnetic roller 117, and the toner adheres or does not adhere to the position facing the recording electrode 109 depending on the signal from the recording electrode 109, thereby forming an image. form. After the image is formed and displayed in this manner, the image is erased by the cleaning member 113.

This cleaning member 113 is grounded and the first
As shown in FIG. 1, when the recording medium 101 moves from above to below the cleaning section, the toner 107 forming an image on the recording medium 101 is scraped off by the brush 113b of the cleaning member 113 on the recording medium 101. ,
Due to its own weight, it is collected by the image forming unit 104 and used again for image formation.

(Problems to be Solved by the Invention) However, in the case of the above-described conventional technology, a small amount of charge is generated due to friction between the recording medium 101 and the brush 113b. Here, if a large amount of toner is clogged in the brush 113b, the recording medium 101
Since the contact area between the recording medium 101 and the cleaning member 113 is wide, the resistance between the recording medium 101 and the cleaning member 113 is reduced, and the generated charge can be sufficiently flowed to the ground. However, when the amount of toner in the brush 113b decreases, the contact area between the recording medium 101 and the brush 113b decreases, and the contact area between the recording medium 101 and the cleaning member 1 decreases.
13 becomes high, and the electric charge generated by friction remains in the cleaning part.

Then, the residual charge and the toner 1 charged during image formation are
Coupled with the charge caused by 07, the surface of the recording medium 101 becomes positively or negatively charged depending on the material. As a result, when the charged recording medium 101 passes through the image forming section 104, charges remain on the surface of the recording medium 101, so when the next image is formed, the previous image remains in the next image section ( There have been problems such as ghost phenomenon) and toner adhesion to non-image areas (fogging phenomenon).

. Therefore, such a phenomenon may occur when a continuous white image area (area with almost no toner adhesion) is displayed on one screen within one screen area displayed on the display unit, or when only a white image is displayed continuously. As a result, the amount of toner in the brush 113b decreases, making it more likely to occur.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to completely erase the electric charges generated due to the friction of the sliding portion between the erasing means and the recording medium. An object of the present invention is to provide an image forming apparatus and thereby improve image quality.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a conductive magnetic developer is electrostatically deposited on a movable recording medium held on a surface in a display section. An image is formed by adhering to the recording medium, and the developer of the image formed on the recording medium is erased by a conductive erasing means that slides into contact with the surface of the recording medium, and at the same time, the developer remains on the surface of the recording medium through this erasing means. The image forming apparatus is characterized in that the recording medium is provided with a developer adhering area for supplying a certain amount of developer to a sliding contact portion between the erasing means and the recording medium. do.

This developer adhesion area is set in an area other than the image display area.
It may also be provided in the image display area. Furthermore, it may be provided in both the image display area and an area other than the image display area.

Further, a detection means for detecting the charge accumulated on the surface of the recording medium is provided, and a static elimination power source is provided that applies a voltage of opposite polarity to the charge accumulated on the surface of the recording medium to the erasing means based on the detected value of the detection means. It may be configured to provide the following.

(Function) In the image forming apparatus configured as described above, the developer attached to the developer adhesion area of the recording medium is supplied to the sliding contact portion of the erasing member as the recording medium moves, and the erasing member is always in sliding contact. The area is kept filled with developer. Therefore, even if the erasing member makes continuous sliding contact with the white image area of the recording medium, the contact area of the sliding contact area becomes large, so the electrical resistance decreases, and the electric charge generated on the surface of the recording medium during image formation is reduced. , or the electric charge given to the developer, or other electric charge generated by sliding contact between the recording medium and the erasing member during surface image erasing, moves through the conductive erasing means, reducing the amount of charge on the recording medium. do.

Further, in another invention, the charge on the surface of the recording medium is detected by a detection means. Then, by applying a negative voltage to the erasing member when the amount of charge is positive, and applying a positive voltage when the amount of charge is negative, the charge on the recording medium is forcibly removed.

(Example) The present invention will be explained below based on the illustrated example. 1st
The figure shows an image forming apparatus according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes an endlessly formed recording medium, and the recording medium 1 is rotated between a pair of rollers 2 and 3 arranged above and below. An image forming means 4 for forming an image on the recording medium l is provided at a position facing the lower roller 3.

As shown in FIG. 2, this image forming means 4 includes toner 7 as a conductive magnetic developer on the outer periphery of a non-magnetic cylinder 6.
is transported by the magnetic field of the rotating magnet 8. At this time, the recording control unit 10 applies a voltage depending on the image information to the recording electrodes 9 arranged densely along the axial direction of the non-magnetic cylinder 6 between the recording medium l and the recording electrodes 9 to generate the recorded information. An image is formed by depositing toner 7 on the insulating layer 1a of the recording medium 1 in accordance with the above (see Japanese Patent Publication No. 51-46707).

The image displayed on the recording medium 1 is visibly displayed on a display section 12 having an opening formed in the front surface of the main body 11 of the apparatus. On the back side of the recording medium 1, a cleaning member 13 for erasing the image displayed on the recording medium 1 is fixed to the back plate 11a of the apparatus main body 11 via a mounting member 14.

This cleaning member 13 has a cleaning main body 13a.
and a soft, conductive brush 13b as an erasing means, which is positioned so as to rub against the recording medium 1 at an appropriate angle and distance.

In addition to carbon fiber, the materials for this cleaning member (3) include soft plastics (botethylene, polypropylene) that have conductivity through composites, urethane rubber,
Materials such as silicon are applicable.

Further, a non-magnetic member 15 and a magnet 16 for supporting the recording medium 1 are provided at a position facing the cleaning member 13 with the recording medium 1 in between. This magnet 16 is for preventing the toner 7 from scattering when erasing an image. In addition, since this magnet 16 has the function of collecting toner 7 at the tip of the brush 13b, the contact area between the recording medium 1 and the cleaning member 13 is increased (and the recovered toner 7 is utilized by the image forming means 4). It also serves the function of increasing efficiency.

The display unit 12 displays the toner image formed on the front side of the recording medium 1, but the recording medium 1 can form images on two sides, the front side and the back side, and the image on the first side. is displayed on the display section 12, the image on the second surface is located on the back side with respect to the display section 12.

Then, the recording medium 1 is the first one. Image display area 1 on the second side
2A and the non-image display area 1 between each image display area 12A.
It is classified into 2B.

A toner adhesion area is provided in this non-image display area 12B for supplying a predetermined amount of toner to the sliding contact portion between the cleaning member 13 and the recording medium 1. In this embodiment, this toner adhesion area is a black image 17 in which toner 7 adheres as a dark image over the entire non-image display area 12B.
．． 18. This black image 17.18 is controlled by the recording control unit 10 to form a black image 17.18 at the leading edge or trailing edge of the image information, or both the leading edge and the trailing edge, so as to correspond to the non-image display area. controlled.

In other words, even if a white screen is displayed continuously on the display unit 12, the toner 7 is attached to the recording medium l due to the black image 17, 18, and when the recording medium l moves in the direction of the arrow, The black image 17.degree. 18 also moves, and a predetermined amount of toner 7 is always supplied into the brush 13b.

Therefore, the contact area between the recording medium 1 and the cleaning member 13 is wide, and the electric charge generated on the surface of the recording medium 1 during image formation, or the electric charge applied to the toner 7, and furthermore, when erasing the image, is The electric charge generated by the rubbing between the recording medium 1 and the brush 13b serving as an erasing member can be moved through the conductive cleaning member 13, and the surface of the recording medium 1 can be neutralized. As a result, the surface potential of the recording medium 1 becomes constant, and the next image formation can be performed in good condition.

A second embodiment of the invention is shown in FIG. In this second embodiment, unlike the first embodiment, a toner adhesion area is provided in the image display area 12A of the recording medium 1.

In this case, each time the recording control unit 10 turns on the power and displays the specified number of screens, the image display area 12A displays
A black image 3o is formed. In other words, by forming a black image on several screens when the power is turned on, the brush 13
Sufficient toner 7 is replenished during b. If a white image is continuously recorded on the display unit 12, the brush 1
Even if the toner 7 in the toner 3b decreases, the black image 3 is periodically removed before the charge removal efficiency of the surface of the recording medium 1 decreases.
By displaying 0 for several pages, sufficient toner 7 is replenished into the brush 13b in the same way as when the power is turned on.

FIG. 4 shows a third embodiment of the invention. In this third embodiment, a black image as a toner adhesion area is formed in both the image display area 12A and the non-image display area 12B. The other configurations and operations are the same as those in the second embodiment, so their explanations will be omitted.

FIG. 5 shows a fourth embodiment of the invention. Unlike the first to third embodiments, this embodiment does not provide a toner adhesion area on the recording medium 1, and the cleaning member 13
A power source 19 for eliminating static electricity for applying a predetermined voltage to the recording medium 1 and a detection means 20 for detecting the amount of charge on the surface of the recording medium 1 are provided.

FIG. 6 is an enlarged sectional view of the recording medium 1 applied to this fourth embodiment. In the same figure, IA is the surface layer, which is made of a transparent material whose main component is butyral resin, phenol resin, or urethane resin, and the surface film
On the lower surface of A, there is a white layer I consisting of a white inorganic substance such as titanium oxide (TiOz) or aluminum oxide (A120) and an adhesive (acrylic resin, plastic resin).
B is provided. Further, a base material ID made of plastic resin such as polyethylene terephthalate, polyethylene, polypropylene, etc. is provided on the bottom layer of the recording medium 1, and the upper surface thereof is made of aluminum or 1.5% to provide conductivity. A conductive layer IC is provided in which TOl (indium and tin oxide) is vapor deposited.

Also in this fourth embodiment, in order to erase the toner image formed by the image forming means 4 and displayed on the display section 12,
This is done by moving the recording medium 1 in the direction of the arrow in the figure and scraping off the toner 7 on the recording medium 1 with the conductive brush 13b of the cleaning member 13.

By the way, when performing such a charge erasing operation, if the surface layer IA of the recording medium l is made of butyral resin, the surface layer IA may interact with the toner 7 when it passes through the recording electrode 9 for image formation. Positive or negative charges are generated on the surface layer IA due to the rubbing or due to the brush 13b also rubbing against the toner 7 when passing through the cleaning member 13 for image erasing. If image formation is performed again using the positively or negatively charged recording medium 1 in this way, toner will adhere to the white image area of the surface layer IA of the recording medium 1, resulting in deterioration of image quality. .

Although the charge on the surface layer IA can be eliminated to some extent by forming black images 17 and 18 in the non-image area of the recording medium 1 as in the first embodiment, When a material with a high resistance value is used as a layer other than the conductive layer IC and image formation is performed in a low humidity environment, it is not possible to remove the static electricity from the recording medium 1 by the brush 13b alone.
In some cases, it may not be possible to completely eliminate static electricity.

Therefore, in this fourth embodiment, in order to completely eliminate the electric charge generated on the recording medium 1, a voltage having a polarity opposite to that of the electric charge eliminating power source 19 is applied. That is, the detection means 20 detects the amount of charge on the surface layer IA of the recording medium 1, and based on the detected value, a positive voltage is applied when a negative charge is generated, and a negative voltage is applied when a positive voltage is generated. A voltage is applied from a power source 19 through the cleaning member 13 . In this case, it is sufficient that the applied voltage is in the range of -30 to +30V.

As mentioned above, even in the fourth embodiment, the first
In addition to being able to perform stable image erasure at all times as in the third embodiment, it is also possible to perform stable image erasure regardless of the material and environment of the recording medium 1, and to prevent the recording medium 1 from becoming dirty. It also has the effect of being able to record and display high-quality images.

In addition, the voltage forcibly applied by the power supply is -30 to +3
0V, and the current flowing between the recording medium 1 and the cleaning member 13 is several tens of microamperes at most, so there is no need to provide a large power source 19. Therefore, a remarkable effect in preventing toner adhesion can be obtained without increasing the size and cost of the apparatus.

Next, FIGS. 7 to 9 respectively show the fifth embodiment of the present invention.
Examples 1 to 7 are shown. In each of these embodiments, not only the static eliminating power supply 19 is provided as in the fourth embodiment, but also the black images 17, 18, 3 as in the first to third embodiments are provided.
0 is also provided. That is, the fifth
In this embodiment, black images 17 and 18 are provided in the non-image display area 12B as in the first embodiment.

Further, in the sixth embodiment shown in FIG. 8, a static eliminating power source 19 is provided, and a black image 30 is provided in the image display area 12A as in the second embodiment.

Furthermore, in the seventh embodiment shown in FIG. 9, a black image 30.18 is formed in both the non-image display area 12B and the image display area 12A as in the third embodiment, together with the static elimination power supply 19. It was designed to do so.

By using such means, an appropriate amount of toner 7 is always supplied into the brush 13b, and the contact area between the recording medium 1 and the cleaning member 13 is widened, so that the recording medium 1 and the cleaning member 13 can be easily connected to each other during image formation. Electric charges generated by rubbing with the cleaning member 13 can be efficiently eliminated.

The other configurations and operations are the same as those of the fourth embodiment, so their explanations will be omitted.

(Effects of the Invention) The present invention has the above-described structure and operation, and is capable of constantly and reliably supplying developer to the erasing means that rubs and erases an image formed by a magnetic developer on a recording medium. Images can be erased and high quality images can be formed.

Additionally, even if a voltage with the opposite polarity to the charge on the recording medium is applied to the recording medium, unnecessary charges on the surface of the recording medium can be completely eliminated, and magnetic development on non-image areas on the surface of the recording medium can be completely eliminated. It is possible to prevent the adhesion of agents and form high-quality images.

[Brief explanation of the drawing]

1 is a side cross-sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention; FIG. 3 to 5 are side sectional views showing the schematic configuration of image forming apparatuses according to second to fourth embodiments of the present invention, respectively, and FIG. 6 is an enlarged cross-sectional view of one good leaf and one mosquito of the recording medium in FIG. 5. 7 to 9 are schematic configurations of image forming apparatuses according to fifth to seventh embodiments of the present invention. FIG. 10 is a side sectional view showing a schematic configuration of a conventional image forming apparatus. The sectional view, FIG. 11, is an explanatory diagram of the cleaning mechanism shown in FIG. 10. Explanation of symbols 1...Recording medium 2.3...Roller 4...
- Image forming means 6... Non-magnetic cylinder 7... Toner (magnetic conductive developer) 8... Rotating magnet 9... Recording electrode 0...
Recording control unit 12...Display unit 3...Cleaning member 13a...Cleaning body 13b...Brush (erasing means) 7.18.30...Black image 9...Electrode for static elimination 20...・Detection means 2A...
・Image display area 12B...Non-image display area! Figure 10 Country Figure 3

Claims (5)

[Claims] (1) An image is formed by electrostatically adhering a conductive magnetic developer onto a movable recording medium held on the surface of the display unit, and the developer for the image formed on the recording medium In an image forming apparatus that erases charges by a conductive erasing means that comes into sliding contact with the surface of a recording medium, and at the same time erases charges remaining on the surface of the recording medium via the erasing means, the erasing means and the recording are placed on the recording medium. An image forming apparatus characterized in that a developer adhering area for supplying a certain amount of developer is provided at a sliding contact portion with a medium. (2) The image forming apparatus according to claim 1, wherein the developer attachment area is provided in an area other than the image display area of the recording medium. (3) The image forming apparatus according to claim 1, wherein the developer attachment area is provided in an image display area of the recording medium. (4) The image forming apparatus according to claim 1, wherein the developer adhesion area is provided in both an image display area and an area other than the image display area of the recording medium. (5) An image is formed by electrostatically depositing a conductive magnetic developer on a movable recording medium held on the surface of the display unit, and a developer for the image formed on the recording medium. In an image forming apparatus that erases electric charges accumulated on the surface of the recording medium by a conductive erasing means that slides on the surface of the recording medium, and at the same time erases electric charges remaining on the surface of the recording medium via this erasing means. What is claimed is: 1. An image forming apparatus that is provided with a detection means for detecting electric charges, and a charge eliminating power supply that applies a voltage having a polarity opposite to the electric charge accumulated on the surface of a recording medium to an erasing means based on a detection value of the detection means.