Developing method and developing apparatus featuring two latent image developing operations using two electrical fields

• US 6,954,285 B2
• Filed: 04/27/2001
• Issued: 10/11/2005
• Est. Priority Date: 05/02/2000
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Zaima, Nobuhiko, Ogata, Takao, Suzuki, Kazuo
• Primary Examiner(s): TRAN, DOUGLAS Q
• Application Number:
  US09/842,671
• Publication Number:
  US 20020051142A1
• Time in Patent Office: 1,628 Days
• Field of Search: 358 11- 118, 358/3.32, 355/89, 355/106, 355/107, 355/115, 355/126, 399/6, 399/7, 399 26- 28, 399/31, 399 61- 63, 399 49- 55, 270/60, 270/19, 271/288, 271/298
• US Class Current: 358/1.8
• CPC Class Codes: G03G 15/065 Arrangements for controlling the potential of the developing electrode
• CPC Class Codes: G03G 15/0855 the concentration being measured by optical means
• CPC Class Codes: G03G 15/5058 using a test patch
• CPC Class Codes: G03G 2215/00042 Optical detection
• CPC Class Codes: G03G 2215/0177 Rotating set of developing units

Abstract

The present invention provides a developing method for developing a latent image formed on an image bearing member with developer including toner and carrier contained in a developer containing portion, comprising the steps of developing a first latent image for controlling a replenishing amount of the developer to the developer containing portion by a first developing electrical field, and developing a second latent image for controlling gradation of an image by a second developing electrical field, and wherein the first developing electrical field is different from the second developing electrical field.

Claims

1. A developing method for developing a latent image formed on an image bearing member with a developer including a toner and a carrier contained in a developer containing portion, the developing method comprising the steps of:

developing a latent image for controlling a replenishing amount of the developer to the developer containing portion using a first developing electrical field; and

developing the latent image for a normal image using a second developing electrical field,

wherein a changed amount of a density of the developed image with respect to a changed amount of a density of the toner in the developer in the developer containing portion is greater when using the first developing electrical field than when using the second developing electrical field.

2. A developing method according to claim 1, wherein the first developing electrical field is an alternating electrical field.

3. A developing method according to claim 1 or 2, wherein the second developing electrical field alternately includes a period during which an alternating electrical field is formed and a period during which the alternating field is not formed.

4. A developing method according to claim 1, further comprising the step of:

detecting information corresponding to a density of a developed image obtained by developing using first developing electrical field,

wherein the replenished amount of the developer to the developer containing portion is controlled on the basis of the detected information.

5. A developing method according to claim 1, wherein the first developing electrical field is an alternating electrical field.

6. A developing method according to claim 1, further comprising the step of:

detecting information corresponding to a density of a developed image obtained by developing the first latent image,

wherein a replenished amount of the developer to the developer containing portion is controlled on the basis of the detected information.

7. A developing method according to claim 1, further comprising the steps of:

detecting information corresponding to a density of the developed image obtained by developing the second latent image; and

controlling a gradation of the developed image on the basis of the detected information.

8. A developing method for developing a latent image formed on an image bearing member with a developer including a toner and a carrier contained in a developer containing portion, the developing method comprising the steps of:

developing a first latent image for controlling a replenishing amount of the developer to the developer containing portion using a first developing electrical field; and

developing a second latent image for controlling a gradation of a developed image using a second developing electrical field,

wherein a changed amount of a density of the developed image with respect to a changed amount of a density of the toner in the developer in the developer containing portion is greater when using the first developing electrical field than when using the second developing electrical field.

9. A developing method according to claim 8, wherein the first developing electrical field is an alternating electrical field.

10. A developing method according to claim 8 or 9, wherein the second developing electrical field alternately includes a period during which an alternating electrical field is formed and a period during which the formation of the alternating electrical field is not formed.

11. A developing method according to claim 8, further comprising the step of:

detecting information corresponding to a density of a developed image obtained by developing the first latent image,

wherein the replenished amount of the developer to the developer containing portion is controlled on the basis of the detected information.

12. A developing method according to claim 8, further comprising the steps of:

detecting information corresponding to a density of the developed image obtained by developing the second latent image; and

controlling a gradation of the developed image on the basis of the detected information.

13. A developing apparatus comprising:

a developer containing portion for containing a developer including a toner and a carrier; and

a developer carrying member for carrying the developer,

wherein when a latent image is formed on an image bearing member, a developing electrical field is formed between said image bearing member and said developer carrying member,

wherein the developing apparatus is operable in a plurality of modes including;

a first mode in which a latent image for controlling a replenishing amount of the developer to the developer containing portion is developed using a first developing electrical field; and

a second mode in which a latent image for a normal image is developed using a second developing electrical field,

wherein a changed amount of a density of a developed image with respect to a changed amount of a density of the toner in the developer in the developer containing portion is greater when using the first developing electrical field than when using the second developing electrical field.

14. A developing apparatus according to claim 13, wherein the first developing electrical field is an alternating electrical field.

15. A developing apparatus according to claim 13 or 14, wherein the second developing electrical field alternately includes a period during which an alternating electrical field is formed and a period during which the alternating electrical field is not formed.

16. A developing apparatus according to claim 13, further comprising:

a detector for detecting information corresponding to a density of developed image obtained by developing with the first developing electrical field,

wherein the replenished amount of the developer to said developer containing portion is controlled on the basis of the detected information.

17. A developing apparatus according to claim 13, wherein the first developing electrical field is an alternating electrical field.

18. A developing apparatus according to claim 13, further comprising:

a detector for detecting information corresponding to a density of a developed image obtained by developing the first latent image,

wherein a replenished amount of the developer to said developer containing portion is controlled on the basis of the detected information.

19. A developing apparatus according to claim 13, further comprising:

a detector for detecting information corresponding to a density of a developed image obtained by developing the second latent image; and

a controller for controlling a gradation of the developed image on the basis of the detected information.

20. A developing apparatus comprising:

a developer containing portion for containing a developer including a toner and a carrier; and

a developer carrying member for carrying the developer,

wherein when a latent image is formed on an image bearing member, a developing electrical field is formed between said image bearing member and said developer carrying member,

wherein the developing apparatus is operable in a plurality of modes including;

a first mode in which a first latent image for controlling a replenishing amount of the developer to the developer containing portion is developed using a first developing electrical field; and

a second mode in which a second latent image for controlling gradation of a developed image is developed using a second developing electrical field,

wherein a changed amount of a density of a developed image with respect to a changed amount of a density of the toner in the developer in the developer containing portion is greater when using the first developing electrical field than when using the second developing electrical field.

21. A developing apparatus according to claim 20, wherein the first developing electrical field is an alternating electrical field.

22. A developing apparatus according to claim 20 or 21, wherein the second developing electrical field alternately includes a period during which an alternating electrical field is formed and a period during which the alternating electrical field is not formed.

23. A developing apparatus according to claim 20, further comprising:

a detector for detecting information corresponding to a density of a developed image obtained by developing the first latent image,

wherein the replenished amount of the developer to said developer containing portion is controlled on the basis of the detected information.

24. A developing apparatus according to claim 20, further comprising a detector for detecting information corresponding to a density of a developed image obtained by developing the second latent image;

and

a controller for controlling a gradation of the developed image on the basis of the detected information.