Image display medium, image-forming method and image-forming apparatus capable of repetitive writing on the image display medium

• US 6,407,763 B1
• Filed: 07/21/2000
• Issued: 06/18/2002
• Est. Priority Date: 07/21/1999
• Status: Expired due to Term

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Machida, Yoshinori, Shigehiro, Kiyoshi, Sakamaki, Motohiko, Kakinuma, Takeo, Yamaguchi, Yoshiro, Koshimizu, Minoru, Oba, Shota, Nakayama, Nobuyuki
• Primary Examiner(s): PENDEGRASS, JOAN H
• Application Number:
  US09/621,546
• Time in Patent Office: 697 Days
• Field of Search: 347/111, 347/122, 347/151, 347/153, 430/19, 430/32, 430/41, 345/84, 345/107, 359/290, 359/296, 399/158, 399/131
• US Class Current: 347/112
• CPC Class Codes: B41M 5/20 using electric current B41M5/24 takes precedence ; processes in which the current is transformed into a heat pattern for obtaining transfer to a receptor sheet B41M5/382; electro-coagulable or electro-adhesive printing or recording B41C1/105
• CPC Class Codes: G02F 1/1671 involving dry toners
• CPC Class Codes: G02F 1/1685 Operation of cells; Circuit arrangements affecting the entire cell
• CPC Class Codes: G03G 15/6597 the imaging being conformed directly on the copy material, e.g. using photosensitive copy material, dielectric copy material for electrostatic printing
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field

Abstract

Provided are an image display medium which satisfies, a safety and a high-speed response and which is capable of repetitive rewriting, an image-forming method in which an image can be formed on the image display medium, and an image-forming apparatus. An image display medium is formed by interposing black particles and white particles between a display substrate and a non-display substrate made of a dielectric. A printing electrode first applies an AC voltage to frictionally charge the black and white particles, and then applies a DC voltage adapted to an image between the substrates. The black particles adhered to a portion (non-image portion) to which the voltage of the display substrate is applied are moved to the non-display substrate.

Claims

1. An image display medium comprising:

a pair of substrates, and a space defined between them, with at least one of a gas disposed in the space and partial vacuum formed in the space; and

plural types of particle groups contained between the substrates to be movable therebetween by an applied electric field, the plural types of particle groups being different in color and charging property.

2. The image display medium as claimed in claim 1, wherein at least two types of the particle groups are mutually moved in opposite directions by the applied electric field.

3. The image display medium as claimed in claim 1, wherein the filling rate of the plural types of the particle groups contained between the substrates is not less than 0.1% and not more than 50%.

4. The image display medium as claimed in claim 1, wherein when the average particle diameter of each particle group is 2r, the particles of the particle groups have an average amount of charge of not less than ±

5×

(r²/10²) fC per particle and not more than ±

150×

(r²/10²) fC per particle.

5. The image display medium as claimed in claim 1, wherein an additive is incorporated in the surfaces of the particles of at least one type of the particle groups, and the additive contains a titanium compound obtained by the reaction of TiO(OH)₂ and a silane compound.

6. The image display medium as claimed in claim 1, wherein at least one type of the particle groups has a magnetic property.

7. The image display medium as claimed in claim 1, further comprising:

a cell structure composed of cells of a predetermined shape between the substrates.

8. The image display medium as claimed in claim 1, further comprising:

a cell structure composed of cells of a predetermined shape between the substrates,

wherein the particle groups are contained in the cells corresponding to respective plural colors forming a multicolor image.

9. The image display medium as claimed in claim 1, wherein matrix electrodes are formed on the pair of substrates.

10. The image display medium as claimed in claim 1, wherein a pixel electrode is formed on one of the pair of substrates, and an electrode is formed on the other substrate.

11. The image display medium as claimed in claim 1, wherein a photoconductive layer is formed on one of the pair of substrates.

12. The image display medium as claimed in claim 1, wherein a photoconductive layer is formed on one of the pair of substrates, and at least one type of the particle groups contains particles formed of a photoconductive material.

13. An image-forming method in which the image is formed on the image display medium as claimed in claim 1, the method comprising the steps of:

forming on a latent image carrier an electrostatic latent image corresponding to an image; and

generating an electric field between a counter electrode and the latent image carrier, the counter electrode being mounted in a position facing the latent image carrier such that the image display medium can be positioned therebetween.

14. An image-forming apparatus in which the image is formed on the image display medium as claimed in claim 1, the image-forming apparatus comprising:

electric field-generating means for generating an electric field according to the image between the pair of substrates.

15. An image-forming apparatus for forming an image on an image display medium, comprising:

the image display medium comprising a pair of substrates, plural types of particle groups contained between the substrates to be movable therebetween by an applied electric field, the plural types of particle groups being different in color and charging property, and a photoconductive layer being formed on one of the pair of substrates;

voltage-applying means for applying a voltage between the pair of substrates;

a transparent panel formed according to a pattern corresponding to the image; and

a light source for irradiating the transparent panel with light.

16. An image-forming apparatus for forming an image on an image display medium, comprising:

the image display medium comprising a pair of substrates, and a space defined between them, with at least one of a gas disposed in the space and partial vacuum formed in the space, and plural types of particle groups contained between the substrates to be movable therebetween by an applied electric field, the plural types of the particle groups being different in color and charging property;

a latent image carrier;

electrostatic latent image forming means for forming on the latent image carrier an electrostatic latent image corresponding to an image; and

a counter electrode for generating an electric field between itself and the latent image carrier, the counter electrode being mounted in a position facing the latent image carrier such that the image display medium can be positioned therebetween.

17. The image-forming apparatus as claimed in claim 16, wherein a bias voltage is applied to the counter electrode.

18. The image-forming apparatus as claimed in claim 16, further comprising:

inputting means for inputting whether a medium on which the image is formed is the image display medium or an image-recording medium;

developing means for developing the electrostatic latent image formed by the electrostatic latent image forming means with a toner when the result inputted by the inputting means is the image-recording medium;

transferring means for transferring the toner image developed by the developing means onto the image-recording medium; and

fixing means for fixing the toner image transferred onto the image-recording medium.

19. The image-forming apparatus as claimed in claim 16, further comprising:

medium-detecting means for detecting whether a medium on which the image is formed is the image display medium or an image-recording medium;

developing means for developing the electrostatic latent image formed by the electrostatic latent image forming means with a toner when the result inputted by the inputting means is the image-recording medium;

transferring means for transferring the toner image developed by the developing means onto the image-recording medium; and

fixing means for fixing the toner image transferred onto the image-recording medium.

20. The image-forming apparatus as claimed in claim 16, further comprising:

inputting means for inputting whether a medium on which the image is formed is the image display medium or an image-recording medium;

developing means for developing the electrostatic latent image formed by the electrostatic latent image forming means with a toner when the result inputted by the inputting means is the image-recording medium;

a counter electrode for transferring the toner image developed by the developing means onto the image-recording medium; and

fixing means for fixing the toner image transferred onto the image-recording medium.

21. The image-forming apparatus as claimed in claim 16, further comprising:

inputting means for inputting whether a medium on which the image is formed is the image display medium or an image-recording medium;

developing means for developing the electrostatic latent image formed by the electrostatic latent image forming means with a toner when the result inputted by the inputting means is the image-recording medium;

a counter electrode for transferring the toner image developed by the developing means onto the image-recording medium; and

fixing means for fixing the toner image transferred onto the image-recording medium,

wherein the fixing by the fixing means is not conducted when the result inputted by the inputting means is the image display medium.

22. The image-forming apparatus as claimed in claim 16, further comprising:

inputting means for inputting whether a medium on which the image is formed is the image display medium or an image-recording medium;

developing means for developing the electrostatic latent image formed by the electrostatic latent image forming means with a toner when the result inputted by the inputting means is the image-recording medium;

a counter electrode for transferring the toner image developed by the developing means onto the image-recording medium;

fixing means for fixing the toner image transferred onto the image-recording medium; and

development stopping means for stopping the development by the developing means when the result inputted by the inputting means is the image display medium.

23. The image-forming apparatus as claimed in claim 16, further comprising:

charging means for previously charging the particle groups.

24. The image-forming apparatus as claimed in claim 16, further comprising:

charging means for previously charging the particle groups by applying at least one of a DC voltage and an AC voltage to the substrates.

25. The image-forming apparatus as claimed in claim 16, further comprising:

vibrating means for vibrating the substrates as charging means for previously charging the particle groups.

26. The image-forming apparatus as claimed in claim 16, further comprising:

charging means for previously charging the particle groups by applying an alternating magnetic field to the image display medium,

wherein at least one type of the particle groups has a magnetic property.

27. An image-forming method comprising the step of:

just before applying an electric field according to image information, applying an alternating electric field to plural types of particle groups contained between substrates in an image display medium to be movable therebetween by an applied electric field, the plural types of particle groups being different in color and charging property.

28. The image-forming method as claimed in claim 27, wherein the alternating electric field is applied to the whole surface of the image display medium simultaneously.

29. The image-forming method as claimed in claim 27, wherein the alternating field is applied, just before the electric field according to the image information is applied, according to a sequence for applying an electric field in a line unit.

30. The image-forming method as claimed in claim 27, wherein an amplitude of the alternating electric field is reduced with the lapse of time.

31. The image-forming method as claimed in claim 27, wherein a voltage waveform of the alternating electric field is rectangular.

32. An image display medium comprising:

a first member;

a second member mounted facing the first member;

first particles contained in a space formed between the first member and the second member, the first particles being moved toward the first member by an electric field applied between the first member and the second member; and

second particles contained in the space, which are different in color from the first particles, the second particles being moved toward the second member by the electric field applied between the first member and the second member.

33. An image display medium comprising:

a first member;

a second member mounted facing the first member;

first particles contained in a space formed between the first member and the second member, the first particles being charged positively or negatively; and

second particles contained in the space, which are different in color from the first particles, the second particles being charged opposite in polarity to that of the first particles.

34. An image display medium comprising:

a first member;

a second member mounted facing the first member;

first particles contained in a space formed between the first member and the second member, the first particles having an insulating property on at least the surfaces thereof and being charged positively; and

second particles contained in the space, which are different in color from the first particles, the second particles having an insulating property on at least the surfaces thereof and being charged negatively.

35. An image display medium comprising:

a first member;

a second member mounted facing the first member;

first particles contained in a space formed between the first member and the second member, the first particles having an insulating property on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an electron-transporting property or a hole-transporting property on at least the surfaces thereof.

36. An image display medium comprising:

a first member having a conductivity;

a second member mounted facing the first member and having a hole-transporting property or an electron-transporting property;

first particles contained in a space formed between the first member and the second member, the first particles having an insulating property on at least the surfaces thereof and being charged positively or negatively; and

second particles contained in the space, which are different in color from the first particles, the second particles having a conductivity on at least the surfaces thereof.

37. An image display medium comprising:

a first member having a hole-transporting property;

a second member mounted facing the first member and having an insulating property or a hole-transporting property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an insulating property on at least the surfaces thereof and being charged positively or negatively.

38. An image display medium comprising:

a first member having an electron-transporting property;

a second member mounted facing the first member and having an electron-transporting property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an insulating property on at least the surfaces thereof and being charged positively.

39. An image display medium comprising:

a first member having an insulating property or an electron-transporting property;

a second member mounted facing the first member and having an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an insulating property on at least the surfaces thereof and being charged positively or negatively.

40. An image display medium comprising:

a first member having an electron-transporting property;

a second member mounted facing the first member and having an electron-transporting property or an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a hole-transporting property on at least the surfaces thereof and being charged positively; and

second particles contained in the space, which are different in color from the first particles, the second particles having a hole-transporting property on at least the surfaces thereof and being charged negatively.

41. An image display medium comprising:

a first member having an insulating property;

a second member mounted facing the first member and having an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a hole-transporting property on at least the surfaces thereof and being charged positively; and

second particles contained in the space, which are different in color from the first particles, the second particles having a hole-transporting property on at least the surfaces thereof and being charged negatively.

42. An image display medium comprising:

a first member;

a second member mounted facing the first member;

first particles contained in a space formed between the first member and the second member, the first particles having a hole-transporting property on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an electron-transporting property on at least the surfaces thereof.

43. An image display medium comprising:

a first member having an electron-transporting property or an insulating property;

a second member mounted facing the first member and having an electron-transporting property or an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a hole-transporting property on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having a conductivity on at least the surfaces thereof.

44. An image display medium comprising:

a first member having a hole-transporting property;

a second member mounted facing the first member and having a hole-transporting property or an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having an electron-transporting property on at least the surfaces thereof and being charged positively; and

second particles contained in the space, which are different in color from the first particles, the second particles having an electron-transporting property on at least the surfaces thereof and being charged negatively.

45. An image display medium comprising:

a first member having an insulating property;

a second member mounted facing the first member and having an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having an electron-transporting property on at least the surfaces thereof and being charged positively; and

second particles contained in the space, which are different in color from the first particles, the second particles having an electron-transporting property on at least the surfaces thereof and being charged negatively.

46. An image display medium comprising:

a first member having a hole-transporting property or an insulating property;

a second member mounted facing the first member and having an insulating property or a hole-transporting property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an electron-transporting property on at least the surfaces thereof.

47. An image display medium comprising:

a first member having a conductivity;

a second member mounted facing the first member and having a conductivity or an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an insulating property on at least the surfaces thereof.

48. An image display medium comprising:

a first member having a hole-transporting property;

a second member mounted facing the first member and having an electron-transporting property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an insulating property on at least the surfaces thereof.

49. An image display medium comprising:

a first member having a conductivity;

a second member mounted facing the first member and having a hole-transporting property, a conductivity or an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having a hole-transporting property on at least the surfaces thereof.

50. An image display medium comprising:

a first member having a hole-transporting property;

a second member mounted facing the first member and having an electron-transporting property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having a hole-transporting property or an electron-transporting property on at least the surfaces thereof.

51. An image display medium comprising:

a first member having a conductivity;

a second member mounted facing the first member and having an electron-transporting property, a conductivity or an insulating property;

first particles contained in a space formed between the first member and the second member, the first particles having a conductivity on at least the surfaces thereof; and

second particles contained in the space, which are different in color from the first particles, the second particles having an electron-transporting property on at least the surfaces thereof.