Image forming apparatus, liquid discharging head, image forming method, recorded matter, and recording liquid

• US 20080024536A1
• Filed: 07/24/2007
• Published: 01/31/2008
• Est. Priority Date: 07/25/2006
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Hirano, Masanori, Inoue, Tomohiro, Yoshida, Takahiro, Yoshida, Masakazu, Ohta, Yoshihisa, Morohoshi, Naoya, Kimura, Shigeaki
• Granted Patent: US 7,527,351 B2
• Time in Patent Office: Days
• US Class Current: 347/13
• CPC Class Codes: B41J 11/009 Detecting type of paper, e.g. by automatic reading of a code that is printed on a paper package or on a paper roll or by sensing the grade of translucency of the paper
• CPC Class Codes: B41J 2/055 Devices for absorbing or preventing back-pressure
• CPC Class Codes: B41J 2/155 for line printing
• CPC Class Codes: B41J 2/2107 characterised by the ink properties supplying ink in a solid state B41J2/17593
• CPC Class Codes: B41J 2002/14419 Manifold
• CPC Class Codes: C09D 11/322 Pigment inks

Abstract

A disclosed image forming apparatus includes a line-type liquid discharging head including nozzles configured to jet liquid droplets. The nozzles are aligned in a sheet width direction. The line-type liquid discharging head includes plural nozzle rows each including an alignment of a plurality of the nozzles configured to discharge liquid droplets of the same color. A distance L1 between the nozzle rows is L1=T11×V1, where T1 is a liquid transfer amount impregnating time of a standard sheet and V1 is a sheet conveying speed.

Claims

1. An image forming apparatus comprising:

a line-type liquid discharging head comprising nozzles configured to jet liquid droplets, the nozzles being aligned in a sheet width direction, wherein;

the line-type liquid discharging head comprises plural nozzle rows each comprising an alignment of a plurality of the nozzles configured to jet liquid droplets of the same color; and

a distance L1 between the nozzle rows is L1=T1×

V1, where T1 is a liquid transfer amount impregnating time of a standard sheet and V1 is a sheet conveying speed.

2. The image forming apparatus according to claim 1, wherein:

the line-type liquid discharging head comprises plural head units each comprising one of the nozzle rows, each of the nozzle rows comprising an alignment of a plurality of the nozzles configured to jet liquid droplets of the same color; and

a distance L11 between the head units is L11=T1×

V1, where T1 is the liquid transfer amount impregnating time of the standard sheet and V1 is the sheet conveying speed.

3. The image forming apparatus according to claim 2, wherein:

a change is made such that the distance L11 between the head units is changed to a distance L12 (L12=L11×

(T1/T2)) in the event that a liquid transfer amount impregnating time T2 of a sheet to be used is different from the liquid transfer amount impregnating time T1 of the standard sheet.

4. The image forming apparatus according to claim 3, wherein:

in the event that the distance L12 between the head units, which distance L12 corresponds to the liquid transfer amount impregnating time T2 of the sheet to be used, is changed to a distance L13 that is longer than the distance L12, changes are made such that a sheet conveying speed V2 applied to the sheet to be used is changed to a sheet conveying speed V3 that is higher than the sheet conveying speed V2 and a head driving frequency f2 applied to the sheet to be used is changed to a head driving frequency f3 that is higher than the head driving frequency f2.

5. The image forming apparatus according to claim 1, wherein:

changes are made such that a sheet conveying speed V2 applied to a sheet to be used is determined such that V2=V1×

(T2/T1) and a head driving frequency f2 applied to the sheet to be used is determined such that f2=f1×

(T2/T1) according to a liquid transfer amount impregnating time T2 of the sheet to be used, where T1 is a liquid transfer amount impregnating time of a standard sheet, V1 is a sheet conveying speed applied to the standard sheet, and f1 is a head driving frequency applied for forming an image on the standard sheet.

6. The image forming apparatus according to claim 1, wherein:

the nozzles are aligned in a sheet conveying direction and the liquid discharging head is configured to be scanned in a direction orthogonal to the sheet conveying direction, wherein;

changes are made such that a liquid discharging head scanning speed U2 applied to a sheet to be used is determined such that U2=U1×

(T2/T1) and a head driving frequency f2 applied to the sheet to be used is determined such that f2=f1×

(T2/T1) according to a liquid transfer amount impregnating time T2 of the sheet to be used, where T1 is a liquid transfer amount impregnating time of a standard sheet, U1 is a liquid discharging head scanning speed applied to the standard sheet, and f1 is a head driving frequency applied for forming an image on the standard sheet.

7. The image forming apparatus according to claim 3, wherein:

the change is made according to a sheet type specified from the outside or a detected sheet type.

8. The image forming apparatus according to claim 1, wherein:

the liquid transfer amount impregnating time T1 of the standard sheet corresponds to time required for pigment-based ink to impregnate commercial/publication-use coated paper.

9. The image forming apparatus according to claim 8, wherein:

the commercial/publication-use coated paper comprises a recording medium comprising a base and a coating layer coating at least one side of the base; and

a transfer amount of pure water into the recording medium falls in a range of 4 ml/m² through 26 ml/m² during a contact time of 100 ms and a transfer amount of pure water into the recording medium falls in a range of 5 ml/m² through 29 ml/m² during a contact time of 400 ms, as measured with a dynamic scanning liquid absorption meter under the conditions of 23°

C. and 50% RH.

10. The image forming apparatus according to claim 8, wherein:

the commercial/publication-use coated paper comprises a recording medium comprising a base and a coating layer coating at least one side of the base; and

a transfer amount of recording liquid into the recording medium falls in a range of 4 ml/m² through 15 ml/m² during a contact time of 100 ms and a transfer amount of recording liquid into the recording medium falls in a range of 7 ml/m² through 20 ml/m² during a contact time of 400 ms, as measured with a dynamic scanning liquid absorption meter under the conditions of 23°

C. and 50% RH.

11. The image forming apparatus according to claim 8, wherein:

surface tension of the pigment-based ink is 15 mN/m or more and 35 mN/m or less.

12. The image forming apparatus according to claim 8, wherein:

the pigment-based ink comprises a fluorochemical surface active agent expressed by the following general formula (A),

CF₃CF₂(CF₂CF₂)m—

CH₂CH₂O(CH₂CH₂O)nH  

 

(A)

where m represents an integer number that falls in a range of 0 through 10 and n represents an integer number that falls in a range of 0 through 40.

13. The image forming apparatus according to claim 1, wherein:

dot rows comprising an alignment of dots extending in a recording direction are recorded as the nozzles jet the liquid droplets; and

the dot rows are recorded in such a manner that recording positions of odd numbered dot rows and recording positions of even numbered dot rows are shifted from each other by half a resolution in the recording direction.

14. The image forming apparatus according to claim 13, wherein:

the dot rows are recorded in such a manner as to be shifted from each other by half a resolution according to a sheet type specified from the outside or a detected sheet type.

15. An image forming method of forming an image using a line-type liquid discharging head comprising nozzles configured to jet liquid droplets, the nozzles being aligned in a sheet width direction, the image forming method comprising the step of:

forming the image by using the line-type liquid discharging head comprising plural nozzle rows each comprising an alignment of a plurality of the nozzles configured to jet liquid droplets of the same color, wherein;

a distance L1 between the nozzle rows is L1=T1×

V1, where T1 is a liquid transfer amount impregnating time of a standard sheet and V1 is a sheet conveying speed.

16. The image forming method according to claim 15, the image forming method comprising the step of:

forming the image by using the line-type liquid discharging head comprising plural head units each comprising a nozzle row comprising an alignment of a plurality of the nozzles configured to jet liquid droplets of the same color, wherein;

a distance L11 between the head units is L11=T1×

V1, where T1 is the liquid transfer amount impregnating time of the standard sheet and V1 is the sheet conveying speed.

17. The image forming method according to claim 16, further comprising the step of:

making a change such that the distance L11 between the head units is changed to a distance L12 (L12=L11×

(T1/T2)) in the event that a liquid transfer amount impregnating time T2 of a sheet to be used is different from the liquid transfer amount impregnating time T1 of the standard sheet.

18. The image forming method according to claim 17, further comprising the step of:

making changes such that a sheet conveying speed V2 applied to the sheet to be used is changed to a sheet conveying speed V3 that is higher than the sheet conveying speed V2 and a head driving frequency f2 applied to the sheet to be used is changed to a head driving frequency f3 that is higher than the head driving frequency f2, in the event that the distance L12 between the head units, which distance L12 corresponds to the liquid transfer amount impregnating time T2 of the sheet to be used, is changed to a distance L13 that is longer than the distance L12.

19. The image forming method according to claim 15, the image forming method comprising the step of:

making changes such that a sheet conveying speed V2 applied to a sheet to be used is determined such that V2=V1×

(T2/T1) and a head driving frequency f2 applied to the sheet to be used is determined such that f2=f1×

(T2/T1) according to a liquid transfer amount impregnating time T2 of the sheet to be used, where T1 is a liquid transfer amount impregnating time of a standard sheet, V1 is a sheet conveying speed applied to the standard sheet, and fl is a head driving frequency applied for forming an image on the standard sheet.

20. The image forming method according to claim 15, wherein the nozzles are aligned in a sheet conveying direction and the liquid discharging head is configured to be scanned in a direction orthogonal to the sheet conveying direction, the image forming method comprising the step of:

making changes such that a liquid discharging head scanning speed U2 applied to a sheet to be used is determined such that U2=U1×

(T2/T1) and a head driving frequency f2 applied to the sheet to be used is determined such that f2=f1×

(T2/T1) according to a liquid transfer amount impregnating time T2 of the sheet to be used, where T1 is a liquid transfer amount impregnating time of a standard sheet, U1 is a liquid discharging head scanning speed applied to the standard sheet, and f1 is a head driving frequency applied for forming an image on the standard sheet.