WO1996011426A1 - Imaging apparatus and intermediate transfer blanket therefor - Google Patents

Abstract

Imaging apparatus including an imaging surface having a toner image formed thereon and an intermediate transfer member (30, 102, 104), which receives the toner image from the imaging surface and from which it is subsequently transferred. The intermediate transfer member (30, 102, 104) includes a drum (30) having mounting recesses formed therein and an intermediate transfer blanket (104) mounted on the drum (30). The blanket (104) has a layered transfer portion having a transfer surface (109) on one face thereof which receives the toner image and optionally an adhesive layer (126) on the opposite face thereof and a mounting fixture (106), attached to one edge of the layered transfer portion and adapted to mate with the mounting recesses in the drum, whereby the transfer blanket (104) is fixedly and removably mounted on the drum (30).

Description

1 IMAGING .APPARATUS AND INTERMEDIATE TR.ANSFER BLANKET THEREFOR

2 FIELD OF THE INVENTION

3 The present invention relates to image forming and

4 image transfer apparatus especially for use in electrostatic

5 imaging using an intermediate transfer blanket .

6 BACKGROUND OF THE INVENTION

7 The use of an intermediate trans fer member in

8 electrostatic imaging is well known.

9 Various types of intermediate trans fer members are

10 known and are descri bed , f or example i n U . S . Patent s

11 3 , 862 , 848 , 4 , 684 , 238 , 4 , 690 , 539 and 4 , 531 , 825 and in the

12 RELATED APPLICATIONS listed above, the specifications of all

13 of which are incorporated herein by reference.

14 Belt-type intermediate transfer members for use in

15 electrophotography are known in the art and are described,

16 inter alia, in U.S. Patents 3,893,761, 4,684,238 and

17 4,690,539, the specifications of which are incorporated

18 herein by reference.

19 The use of intermediate transfer members and members

20 including transfer blankets for offset ink printing is also

21 well known. Such blankets have characteristics which are

22 suitable for ink transfer but are generally not usable, per

23 se, for liquid toner imaging.

24 SUMMARY OF THE INVENTION

25 The present invention seeks to provide, in one aspect

26 thereof, improved image transfer apparatus using an improved

27 intermediate transfer member.

28 The present invention further seeks to provide, in a

29 second aspect thereof, an improved image transfer member for

30 use in imaging apparatus, especially in image forming

31 apparatus using electrostatically charged toner.

32 The present invention further seeks to provide, in a

33 third aspect thereof, an improved image transfer blanket for

34 use as part of the image transfer member in imaging

35 apparatus, especially in image forming apparatus using

36 electrostatically charged toner. 1 There is thus provided in accordance with a preferred

2 embodiment of the invention, imaging apparatus comprising:

3 an imaging surface having an image, preferably a toner

4 image formed thereon; and

5 an intermediate transfer member, which receives the

6 toner image from the imaging surface and from which it is

7 subsequently transferred, comprising:

8 a drum having mounting recesses formed therein;

9 and

10 an intermediate transfer blanket mounted on the

11 drum, the blanket comprising:

12 a layered transfer portion having a transfer

13 surface on one face thereof which receives the toner image

14 and preferably an adhesive layer on an opposite surface

15 thereof; and

16 a mounting fixture, attached to only one

17 edge of the layered transfer portion and adapted to mate

18 with the mounting recesses in the drum,

19 whereby the transfer blanket is removably mounted on

20 the drum.

21 In a preferred embodiment of the invention at least a

22 portion of a surface of the layered transfer portion

23 opposite to the transfer surface is bonded to the drum.

24 Preferably, the layered transfer portion comprises an

25 electrically conductive layer underlying the transfer

26 surface; and the mounting fixture comprises an electrically

27 conductive element, attached to one edge of the transfer

28 portion, which is electrically connected to the electrically

29 conductive layer.

30 I n a pref erred embodiment o f the invention , the

31 electrically conductive element, which preferably comprises

32 at least one " L " shaped f inger- like extension extending

33 therefrom, that contacts the drum , wherein the drum is

34 electrified to a voltage which is operative to transfer the

35 toner image f rom the imaging surf ace to the trans fer

36 surface . Preferably, said at least one " L" shaped extension 1 has a first portion extending in a direction perpendicular

2 to the l ayered trans f er portion and a second portion

3 attached and substantially perpendicular to the first

4 portion and extending substantially parallel to and away

5 from the layered transfer portion.

6 Preferably , the mounting recesses further comprise 7 recesses therein which receive said second portion.

8 There i s f urther provided in accordance wi th a

9 preferred embodiment of the invention , a substantially

10 rectangular intermediate transfer blanket comprising:

11 a layered transfer portion having a transfer surface on

12 one face thereof ; and

13 a mounting fixture, adapted for mounting the blanket on

14 a drum , attached to only one edge of the layered transfer

15 portion.

16 Preferably, the layered transfer portion comprises an

17 electrically conductive layer underlying the trans fer

18 surface; and the mounting fixture comprises an electrically

19 conductive element , attached to one edge of the transfer

20 portion, which is electrically connected to the electrically

21 conductive layer .

22 Pref erably , the electrical ly conductive element

23 comprises at least one " L" shaped f inger-like extension

24 extending therefrom, which extension preferably has a first

25 portion extending in a direction perpendicular to the

26 layered transfer portion and a second portion attached and

27 subs t ant i al ly perpend icular to the f i rs t port ion and

28 extending substantial ly paral lel to and away f rom the

29 layered transfer portion.

30 In a preferred embodiment of the invention the layered

31 transfer portion comprises a conformal layer formed of a

32 material having a Shore A hardness of les s than 65 ,

33 preferably less than about 50 and more than about 30.

34 Preferably, the transfer surface is a release layer for

35 toner .

36 There is further provided in accordance with a 1 preferred embodiment of the invention, a substantially

2 rectangular intermediate transfer blanket comprising:

3 a layered transfer portion having a transfer surface on

4 one face and including a conductive layer underlying the

5 transfer surface; and

6 a conductive element, attached to one edge of the

7 transfer portion, which is electrically connected to the

8 conducting layer.

9 There i s f urther provided i n accordance wi th a

10 pref erred embodiment o f the invent ion , a l ayered

11 intermediate transfer member and blanket comprising :

12 a transfer surface on one face; and

13 a conforming layer having a shore A hardness of less

14 than about 65 , preferably less than about 50 and preferably

15 more than about 30.

16 There is f urther provided in accordance with a

17 pref erred embodiment of the invention , a layered

18 intermediate transfer blanket comprising:

19 a transfer surface on one face of the blanket; and

20 an adhesive layer on the opposite face of the blanket

21 which i s stable at a temperature o f at least 80 ^β C ,

22 preferably above 100 ^β C , more preferably above 120 ° C , most

23 preferably above 150°C .

24 There is further provided in a preferred embodiment of

25 the invention , a layered intermediate transfer blanket

26 comprising:

27 an transfer surface on one face of the blanket; and

28 a soft layer on the opposite face of the blanket which

29 has a Shore A hardness of less than 90, more preferably less

30 than 45, most preferably less than 25.

31 In a preferred embodiment of the invention the soft

32 layer comprises an acrylic polymer.

33 In a preferred embodiment of the invention the layered

34 transfer portion comprises an adhesive layer on a side

35 thereof opposite to the transfer surface.

36 There is further provided in accordance with a 1 preferred embodiment of the invention, imaging apparatus for

2 performing an imaging process, comprising:

3 an imaging surface having a liquid toner image

4 comprising toner particles and carrier liquid formed

5 thereon; and

6 an intermediate transfer member, which receives the

7 toner image from the imaging surface and from which it is

8 subsequently transferred, comprising:

9 a layered transfer portion having a transfer

10 surface on one face thereof which receives the toner image;

11 a resilient layer underlying the transfer surface

12 which comprises a material which is at least partly

13 leachable by the carrier liquid; and

14 a barrier layer, preferably comprising at least

15 partially hydrolyzed polyvinyl alcohol, that is

16 substantially impervious to the carrier liquid and is

17 situated intermediate the resilient layer and the transfer

18 surface.

19 There is further provided, in a preferred embodiment of

20 the invention a layered intermediate transfer member

21 comprising:

22 a transfer surface;

23 a resilient layer underlying the transfer surface which

24 comprises a material which is at least partly leachable by a

25 liquid hydrocarbon; and

26 a barrier layer, preferably comprising at least

27 partially hydrolyzed polyvinyl alcohol, that is

28 substantially impervious to the liquid hydrocarbon and is

29 situated intermediate the resilient layer and the transfer

30 surface.

31 There is further provided, in accordance with a

32 preferred embodiment of the invention, a layered

33 intermediate transfer member for receiving liquid toner

34 images comprising toner particles and carrier liquid

35 comprising:

36 a transfer surface; 1 a resilient layer underlying the transfer surface which

2 comprises a material which is at least partly leachable in

3 the carrier liquid; and

4 a barrier layer, preferably comprising at least

5 partially hydrolyzed polyvinyl alcohol, that is

6 substantially impervious to the carrier liquid and is

7 situated intermediate the resilient layer and the transfer

8 surface.

9 There is further provided, in accordance with a

10 preferred embodiment of the invention, imaging apparatus for

11 performing an imaging process, comprising:

12 an imaging surface having a liquid toner image

13 comprising toner particles and carrier liquid formed

14 thereon; and

15 an intermediate transfer member, which receives the

16 toner image from the imaging surface and from which it is

17 subsequently transferred, comprising:

18 a layered transfer portion having a transfer

19 surface on one face thereof which receives the toner image;

20 a resilient layer underlying the transfer surface

21 which comprises a material which interferes with the

22 operation of the imaging process;

23 a barrier layer, preferably comprising at least

24 partially hydrolyzed polyvinyl alcohol, that is

25 substantially impervious to the interfering material

26 comprised in the resilient layer and is situated

27 intermediate the resilient layer and the transfer surface.

28 In a preferred embodiment of the invention, the

29 material is a gas and the barrier layer is a barrier layer

30 for gasses.

31 There is further provided, in accordance with a

32 preferred embodiment of the invention, a layered

33 intermediate transfer member, comprising:

34 a transfer surface;

35 a resilient layer underlying the transfer surface; and

36 a barrier layer, preferably comprising at least 1 partially hydrolyzed polyvinyl alcohol, that is

2 substantially impervious to liquid hydrocarbons and is

3 situated intermediate the resilient layer and the transfer

4 surface.

5 There is further provided, in accordance with a

6 preferred embodiment of the invention, a layered

7 intermediate transfer member, comprising:

8 a transfer surface;

9 a resilient layer underlying the transfer surface which

10 releases gases; and

11 a barrier layer, preferably comprising at least

12 partially hydrolyzed polyvinyl alcohol, that is

13 substantially impervious to the gasses and is situated

14 intermediate the resilient layer and the transfer surface.

15 There is further provided, in accordance with a

16 preferred embodiment of the invention, a layered

17 intermediate transfer member for receiving liquid toner

18 images comprising toner particles and carrier liquid

19 comprising:

20 a transfer surface;

21 a resilient layer underlying the transfer surface

22 comprising a material which is at least partly leachable in

23 the carrier liquid; and

24 a barrier layer, preferably comprising at least

25 partially hydrolyzed polyvinyl alcohol, that is

26 substantially impervious to the carrier liquid and is

27 situated intermediate the resilient layer and the transfer

28 surface. 29

30 31 32 33 34 35 36 1 BRIEF DESCRIPTION OF THE DRAWINGS

2 The present invention will be understood and

3 appreciated more fully from the following detailed

4 description, taken in conjunction with the drawings in

5 which:

6 Fig . 1 is a simplified sectional illustration of

7 electrostatic imaging apparatus constructed and operative in

8 accordance with a preferred embodiment of the present

9 invention;

10 Fig. 2 is a simplified enlarged sectional illustration

11 of the apparatus of Fig. 1;

12 Fig. 3A is a simplified, cross-sectional side view of

13 an intermediate transfer member, including a removable

14 intermediate transfer blanket mounted on a drum, in

15 accordance with a preferred embodiment of the invention;

16 Fig. 3B is a partially cut-away top view of the

17 intermediate transfer member of Fig. 3A;

18 Figs. 4A and 4B are respective top and side views of an

19 intermediate transfer blanket in accordance with a preferred

20 embodiment of the invention;

21 Fig. 4C shows details of the layered construction of

22 the intermediate transfer blanket in accordance with a

23 preferred embodiment of the invention;

24 Fig. 4D is a cut-away expanded view of a securing

25 mechanism on the intermediate transfer blanket of Figs 4A

26 and 4B; and

27 Fig . 5 is a simplified cross- sectional illustration of

28 a portion of an intermediate transfer member , including a

29 removable intermediate transfer blanket mounted on a drum in

30 accordance wi th another pre ferred embodiment o f the

31 invention . 32

33 34 35 36 1 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

2 Reference is now made to Figs . 1 and 2 which illustrate

3 a multicolor electrostatic imaging system constructed and

4 operative in accordance with a preferred embodiment of the

5 present invent ion . As seen in Figs . 1 and 2 there i s

6 provided an imaging sheet , preferably an organic

7 photoreceptor 12 , typically mounted on a rotating drum 10.

8 Drum 10 is rotated about its axis by a motor or the like

9 ( not shown ) , in the direction of arrow 18 , past charging

10 apparatus 14 , preferably a corotron, scorotron or roller

11 charger or other suitable charging apparatus known in the

12 art and which i s adapted to charge the surface of sheet

13 photoreceptor 12. The image to be reproduced is focused by

14 an imager 16 upon the charged surface 12 at least partially

15 discharging the photoconductor in the areas struck by light ,

16 thereby forming the electrostatic latent image . Thus , the

17 latent image normally includes image areas at a f irst

18 e lectrica l potent i al and background area s at another

19 electrical potential .

20 Photoreceptor sheet 12 may use any sui table

21 arrangement of layers of materials as is known in the art,

22 however , in the preferred embodiment of the photoreceptor

23 sheet , certain of the layers are removed from the ends of

24 the sheet to facilitate its mounting on drum 10.

25 This pre ferred photoreceptor sheet and preferred

26 methods of mounting it on drum 10 are described in a co-

27 pending U. S . Patent application of Belinkov et al . , IMAGING

28 APPARATUS AND PHOTORECEPTOR THEREFOR, filed September 7 ,

29 1994 , assigned serial number 08/301 , 775 , and on applications

30 filed in other countries claiming priority therefrom, the

31 disclosure of which is incorporated herein by reference .

32 Alternatively, photoreceptor 12 may be deposited on the drum

33 10 and may form a continuous surf ace . Furthermore ,

34 photoreceptor 12 may be a non-organic type photoconductor

35 based, for example, on a compound of Selenium.

36 Imaging apparatus 16 may be a modulated laser beam 1 scanning apparatus, an optical focusing device for imaging a

2 copy on a drum or other imaging apparatus such as is known

3 in the art.

4 Also associated with drum 10 and photoreceptor sheet

5 12 , in the preferred embodiment of the invention, are a

6 multicolor liquid developer spray assembly 20, a developing

7 assembly 22, color specific cleaning blade assemblies 34, a

8 background cleaning station 24, an electrified squeegee 26,

9 a background discharge device 28 , an intermediate transfer

10 member 30 , cleaning apparatus 32 , and , opt ional ly , a

11 neutralizing lamp assembly 36.

12 Develop ing a s semb ly 22 pre f erably includes a

13 development roller 38. Development roller 38 is preferably

14 spaced f rom photoreceptor 12 thereby f orming a gap

15 therebetween of typically 40 to 150 micrometers and is

16 charged to an electrical potential intermediate that of the

17 image and background areas of the image. Development roller

18 38 is thus operative, when maintained at a suitable voltage,

19 to apply an electric field to aid development of the latent

20 electrostatic image.

21 Development roller 38 typically rotates in the same

22 sense as drum 10 as indicated by arrow 40 . This rotation

23 provides for the surface of sheet 12 and development roller

24 38 to have opposite velocities at the gap between them.

25 Multicolor liquid developer spray assembly 20 , whose

26 operation and structure is described in detail in U . S .

27 Patent 5 , 117 , 263 , the disclosure of which is incorporated

28 herein by reference , may be mounted on axis 42 to allow

29 assembly 20 to be pivoted in such a manner that a spray of

30 liquid toner containing electrically charged pigmented toner

31 particles can be directed either onto a portion of the

32 development roller 38 , a portion of the photoreceptor 12

33 or directly into a development region 44 between

34 photoreceptor 12 and development roller 38. Alternatively,

35 assembly 20 may be fixed . Preferably, the spray is directed

36 onto a portion of the development roller 38. 1 Color specific cleaning blade assemblies 34 are

2 operatively associated with developer roller 38 for separate

3 removal of residual amounts of each colored toner remaining

4 thereon after development. Each of blade assemblies 34 is

5 selectably brought into operative association with developer

6 roller 38 only when toner of a color corresponding thereto

7 is supplied to development region 44 by spray assembly 20.

8 The construction and operation of cleaning blade assemblies

9 is described in PCT Publication WO 90/14619 and in US patent

10 5,289,238, the disclosures of which are incorporated herein

11 by reference.

12 Each cleaning blade assembly 34 includes a toner

13 directing member 52 which serves to direct the toner

14 removed by the cleaning blade assemblies 34 from the

15 developer roller 38 to separate collection containers 54,

16 56, 58, and 60, for each color to prevent contamination of

17 the various developers by mixing of the colors. The toner

18 collected by the collection containers is recycled to a

19 corresponding toner reservoir (55, 57, 59 and 61). A final

20 toner directing member 62 always engages the developer

21 roller 38 and the toner collected thereat is supplied into

22 collection container 64 and thereafter to reservoir 65 via

23 separator 66 which is operative to separate relatively clean

24 carrier liquid from the various colored toner particles. The

25 separator 66 may be typically of the type described in U.S.

26 Patent 4,985,732, the disclosure of which is incorporated

27 herein by reference.

28 In a preferred embodiment of the invention, as

29 described in U.S. Patent 5,255,058, the disclosure of which

30 is incorporated herein by reference, where the imaging speed

31 is very high, a background cleaning station 24 typically

32 including a reverse roller 46 and a fluid spray apparatus 48

33 is provided. Reverse roller 46 which rotates in a direction

34 indicated by arrow 50 is electrically biased to a potential

35 intermediate that of the image and background areas of

36 photoconductive drum 10, but different from that of the 1 development roller. Reverse roller 46 is preferably spaced

2 apart from photoreceptor sheet 12 thereby forming a gap

3 therebetween which is typically 40 to 150 micrometers.

4 Fluid spray apparatus 48 receives liquid toner from

5 reservoir 65 via conduit 88 and operates to provide a supply

6 of preferably non-pigmented carrier liquid to the gap

7 between sheet 12 and reverse roller 46. The liquid supplied

8 by fluid spray apparatus 48 replaces the liquid removed from

9 drum 10 by development assembly 22 thus allowing the

10 reverse roller 46 to remove charged pigmented toner

11 particles by electrophoresis from the background areas of

12 the latent image. Excess fluid is removed from reverse

13 roller 46 by a liquid directing member 70 which continuously

14 engages reverse roller 46 to collect excess liquid

15 containing toner particles of various colors which is in

16 turn supplied to reservoir 65 via a collection container 64

17 and separator 66.

18 The apparatus embodied in reference numerals 46, 48, 50

19 and 70 is not required for low speed systems, but is

20 preferably included in high speed systems.

21 Preferably, an electrically biased squeegee roller 26

22 is urged against the surface of sheet 12 and is operative to

23 remove liquid carrier from the background regions and to

24 compact the image and remove liquid carrier therefrom in the

25 image regions. Squeegee roller 26 is preferably formed of

26 resilient slightly conductive polymeric material as is well

27 known in the art, and is preferably charged to a potential

28 of several hundred to a few thousand volts with the same

29 polarity as the polarity of the charge on the toner

30 particles.

31 In a first preferred embodiment the squeegee roller is

32 made by molding a soft polyurethane rubber coating onto a

33 metal core, coating the molded core with a conductive

34 lacquer and coating the lacquer with a low conductivity

35 elastomer. Alternatively, in a second embodiment, the molded

36 coating can be made of an elastomer with a controlled 1 conductivity and the lacquer can be omitted. In a third

2 embodiment, a single coating of controlled conductivity

3 elastomer is used and the outer layer is omitted.

4 In the first squeegee embodiment the metal core is

5 cleaned, and coated with a rubber to metal adhesive, such

6 as, for example CILBOND 49 SF (Compounding Ingredients

7 Limited, UK) dissolved in an equal amount of methyl ethyl

8 ketone, which is dried at 110^βC for one hour. An outer mold

9 having a diameter about 9.5 mm greater than that of the core

10 is dip coated with a release agent, such as, for example, a

11 mixture of 10 parts Syl-Off 7600 (Dow Corning), 1 part Syl-

12 Off 7601 and 150 parts n-hexane which is then cured for one

13 hour at 110°C. The space between the core and the mold (pre-

14 heated to 70-80°C) is filled with polyurethane rubber for

15 casting (CIL A 20, Compounding Ingredients Limited, UK)

16 which is preheated under vacuum at 80^βC for 16 hours and

17 then at 120°C for an additional hour. The polyurethane is

18 cured at 135^βC for 8 hours. After cooling and removal of the

19 coated core from the mold (which removal may be aided by a

20 solvent, such as Isopar), the cast material is ground to

21 size to approximately ±5 micrometers. The preferred hardness

22 of the coating is about 20 Shore A, although this hardness

23 may vary from 15-40 Shore A depending on the amount of

24 liquid removal desired.

25 The ground sur f ace i s cleaned wi th acetone and

26 preferably dip coated with a conductive lacquer ( preferably,

27 3 parts H322 ( Lord Corporation , USA ) and 1 part ethyl

28 acetate ) which has been prefiltered through a lint free

29 cloth to give a thicknes s ( a f ter drying ) o f about 30

30 micrometers.

31 A top layer of 50 parts Fomrez 50 (Witco. Corp., USA)

32 dissolved in 75 parts ethyl acetate to which is added 3

33 parts of DC193 (Dow Corning) and about 6 parts of di-phenyl

34 methane 4,4' di-isocyanate (MDI) ( Des odor 44V20

35 manufactured by Bayer, Germany) is filtered and dip coated

36 onto the lacquer coating a plurality of times to achieve a 1 coating thickness of 60-70 micrometers. The coated squeegee

2 is dried at room temperature and cured at 140°C for 2 hours.

3 The preferred hardness of the material forming the outer

4 layer is about 30-35 Shore A and this hardness can be

5 controlled by changing the proportion of MDI in the coating.

6 The coating has a resistivity in the range of 10° to lO¹^

7 ohm-cm, with a preferred value of 1-3x10° to 2-3x10 ohm-cm.

8 In the second embodiment of the squeegee roller, the

9 cast covering for the core is preferably an elastomer having

10 the proper combination of hardness (15-30 Shore A,

11 preferably 20 Shore A) and resistivity (1-10x10^ ohm-cm).

12 This material can be polyurethane, nitrile or other oil

13 resistant rubber. Polyurethane with selectable resistivity

14 and hardness is available from Merthane Products (USA).

15 After casting as described above, the coating is ground to

16 size and finish and coated with a top layer which is made in

17 the same manner as the top layer of the first embodiment.

18 In the third embodiment of the squeegee roller, the top

19 layer is omitted and the conductive elastomer is preferably

20 cast to exact size.

21 Discharge device 28 is operative to flood the sheet 12

22 with light which discharges the voltage remaining on sheet

23 12, mainly to reduce electrical breakdown and improve

24 transfer of the image to intermediate transfer member 30.

25 Operation of such a device in a write black system is

26 described in U.S. Patent 5,280,326, the disclosure of which

27 is incorporated herein by reference.

28 Figs. 1 and 2 further show that multicolor toner spray

29 assembly 20 receives separate supplies of colored toner

30 typically from four different reservoirs 55, 57, 59 and 61.

31 Figure 1 shows four different colored toner reservoirs 55,

32 57, 59 and 61 typically containing the colors Yellow,

33 Magenta, Cyan and, optionally, Black respectively. Pumps 90,

34 92, 94 and 96 may be provided along respective supply

35 conduits 98, 101, 103 and 105 for providing a desired amount

36 of pressure to feed the colored toner to multicolor spray 1 assembly 20. Alternatively, multicolor toner spray assembly

2 20, which is preferably a three level spray assembly,

3 receives supplies of colored toner from up to six different

4 reservoirs (not shown) which allows for custom colored toner

5 in addition to the standard process colors.

6 A preferred type of toner for use with the present

7 invention is that described in Example 1 of U.S. Patent

8 4,794,651, the disclosure of which is incorporated herein by

9 reference or variants thereof as are well known in the art.

10 For colored liquid developers, carbon black is replaced by

11 color pigments as is well known in the art. Other toners may

12 alternatively be employed, including liquid toners and, as

13 indicated above, including powder toners. 4 Another preferred embodiment of the toner for use in

15 the invention is prepared using the following method: 6 1) Solubilizing 1400 grams of Nucrel 925 (ethylene

17 copoly er by Dupont ) and 1400 g of Isopar L (Exxon) are 8 thoroughly mixed in an oil heated Ross Double Planetary 9 Mixer at least 24 RPM for 1.5 hours, with the oil 0 temperature at 130°C. 1200 g of preheated Isopar L is added 1 and mixing is continued for an additional hour. The mixture 2 is cooled to 45 " C, while stirring is continued over a period 3 of several hours, to form a viscous material. 4 2) Milling and Grinding 762 grams of the result of the 5 Solubilizing step are ground in a IS attritor (Union Process 6 Inc. Akron Ohio), charged with 3/16" carbon steel balls at 7 250 RPM, together with 66.7 grams of Mogul L carbon black 8 (Cabot), 6.7 grams of BT 583D (blue pigment produced by 9 Cookson), 5 grams of aluminum tri stearate and an additional 0 1459.6 grams of Isopar L for eight hours at 30°C. 1 3) Continuation of Grinding 34.5 grams of ACumist A-12 2 (a micronised polyethylene wax produced by Allied Signal) is 3 added and grinding is continued for an additional 4 hours. 4 The resulting particles are fibrous particles have a 5 measured diameter in the range of 1-3 micrometers. 6 The resulting material is diluted with additional 1 Isopar L and Marcol 82 to give a working developer in which

2 the dry solids portion is about 1.7% and in which the

3 overall ratio of Isopar L to Marcol is between about 50:1

4 and 500:1, more preferably between about 100:1 and 200:1.

5 Charge director as described in US patent application

6 07/915,291 (utilizing lecithin, BBP and ICIG3300B) and in WO

7 94/02887, in an amount equal to 40 mg/gm of solids, is added

8 to charge the toner particles. Other charge directors and

9 additional additives as are known in the art may also be

10 used.

11 The above described process produces a black toner.

12 Cyan, magenta and yellow toners can be produced by using a

13 different mix of materials for step 2). For Cyan toner, 822g

14 of the solubilized material, 21.33 grams each of BT 583D and

15 BT 788D pigments (Cookson), 1.73 grams of D1355DD pigment

16 (BASF), 7.59 grams of aluminum tri stearate and 1426 grams

17 of Isopar L are used in step 2. For Magenta toner, 810 grams

18 of solubilized material, 48.3 grams of Finess Red F2B, 6.81

19 grams of aluminum tri-stearate and 1434.2 grams of Isopar L

20 are used in step 2. For yellow toner 810 grams of

21 solubilized material, 49.1 grams of D1355DD pigment, 6.9

22 grams of aluminum tri-stearate and 1423 grams of Isopar L

23 are used in step 2.

24 Intermediate transfer member 30, an especially

25 preferred embodiment of which is described in detail below

26 (in conjunction with Figs. 3 and 4), may, for some

27 embodiments of the invention, be any suitable intermediate

28 transfer member having a multilayered transfer portion such

29 as those described below or in US Patents 5,089,856 or

30 5,047,808 or in the applications of which this application

31 is a continuation in part, the disclosures of which are

32 incorporated herein by reference and by other structures

33 known in the art. Member 30 is maintained at a suitable

34 voltage and temperature for electrostatic transfer of the

35 image thereto from the image bearing surface. Intermediate

36 transfer member 30 is preferably associated with a pressure 1 roller 71 for transfer of the image onto a final substrate

2 72 , such as paper, preferably by heat and pressure. For the

3 especi al ly pref erred toner described above , an image

4 temperature of about 95 ^β C at the inception of fusing is

5 preferred.

6 Certain aspects of the present invention, especially

7 the method of mounting a transfer blanket on a drum are of

8 general applicability and are applicable to a wide range of

9 blanket types for ink, liquid toner or powder toner as are

10 known in the art.

11 Cleaning apparatus 32 is operative to scrub clean the

12 surf ace o f photoreceptor 12 and preferably includes a

13 cleaning rol ler 74 , a sprayer 76 to spray a non-polar

14 cleaning liquid to assist in the scrubbing process and a

15 wi per b l ade 78 to complete the cleaning of the

16 photoconductive surface . Cleaning roller 74 which may be

17 formed of any synthetic resin known in the art for this

18 purpose is driven in the same sense as drum 10 as indicated

19 by arrow 80, such that the surface of the roller scrubs the

20 surface of the photoreceptor . Any residual charge left on

21 the surf ace of photoreceptor sheet 12 may be removed by

22 f looding the photoconductive surf ace wi th l ight f rom

23 optional neutralizing lamp assembly 36 , which may not be

24 required in practice.

25 In accordance with a preferred embodiment of the

26 invention, after developing each image in a given color, the

27 single color image is transferred to intermediate transfer

28 member 30 . Subsequent images in di f f erent colors are

29 sequentially transferred in alignment with the previous

30 image onto intermediate transfer member 30. When all of the

31 desired images have been transferred thereto, the complete

32 multi-color image is transferred from transfer member 30 to

33 substrate 72. Impression roller 71 only produces operative

34 engagement between intermediate trans fer member 30 and

35 substrate 72 when trans f er of the compos i te image to

36 substrate 72 takes place . Alternatively, each single color 1 image is separately transferred to the substrate via the

2 intermediate transfer member. In this case, the substrate is

3 fed through the machine once for each color or is held on a

4 platen and contacted with intermediate transfer member 30

5 for composite image transfer. Alternatively, the

6 intermediate transfer member is omitted and the developed

7 single color images are transferred sequentially directly

8 from drum 10 to substrate 72.

9 Figs. 3A, 3B and 4A-4D illustrate a preferred

10 embodiment of intermediate transfer member 30 in accordance

11 with a preferred embodiment of the invention. Fig 3A shows

12 an intermediate transfer blanket 100 mounted on a drum 102.

13 Transfer blanket 100 (whose details are shown in Figs. 4C

14 and 4D) comprises a preferably layered transfer portion 104

15 and a mounting fitting 106.

16 As shown most clearly in Fig. 4C, transfer portion 104

17 comprises a release layer 109 which is outermost on the

18 blanket when it is mounted on drum 102. Underlying layer 109

19 is a conforming layer 111 preferably of a soft elastomer,

20 preferably of polyurethane and preferably having a Shore A

21 hardness of less than about 65, more preferably, less than

22 about 55, but preferably more than about 35. A suitable

23 hardness value is between 45-55, preferably about 50.

24 Underlying layer 111 is a conductive layer 114 which

25 overlays a thin barrier layer 115. Barrier layer 115

26 overlays a blanket body 116 comprising a top layer 118, a

27 compressible layer 120 and a fabric layer 122. Underlying

28 the fabric layer is preferably an adhesive layer 126 which

29 is in contact with drum 102.

30 Drum 102 is preferably heated by an internal halogen

31 lamp heater or other heater to aid transfer of the image to

32 and from the release layer 109 to a final substrate as is

33 well known in the art. Other heating methods, or no heating

34 at all, may also be used in the practice of some aspects of

35 the invention. The degree of heating will depend on the

36 characteristics of the toner and or ink used in conjunction 1 with the invention.

2 As shown in Figs. 4A, 4B and 4D, mounting fitting 106

3 comprises an elongate electrically conducting bar 108, for

4 example of a metal such as aluminum formed with a series of

5 L-shaped mounting legs 110 (in the form of finger-like

6 extensions) which are also conducting, preferably of the

7 same material as bar 108, and preferably formed integrally

8 therewith. In particular, bar 108 is formed with a slot into

9 which the end of layered transfer portion 104 is inserted.

10 Preferably, the end of the layered portion which is inserted

11 into the mounting bar does not have a release layer 109 or

12 conforming layer 111, whereby conducting layer 114 is

13 exposed and is therefore in electrical contact with bar 108.

14 Alternatively, the bar 108 can be formed with sharp internal

15 projections which pierce the outer layers of the blanket and

16 contact the conducting layer.

17 Optionally, each of the layers beneath the conducting

18 layer 114 may be partially conducting (for example, by the

19 addition of conductive carbon black or metal fibers) and the

20 adhesive layer may be conductive, such that current also

21 flows directly from the drum surface to the conducting

22 layer.

23 In one preferred embodiment of the invention, fitting

24 106 is formed of a single sheet of metal, wherein the legs

25 are partially cut from the metal which is bent into a U

26 shape to form the slot into which the layered portion is

27 inserted. After insertion, the outer walls of the slot are

28 forced against the layered portion to secure the layered

29 portion in the slot. The partially cut out portion is bent

30 to form the mounting legs.

31 In the preferred embodiment of the invention shown in

32 Figs. 1-3, drum 102 is maintained at a potential suitable

33 for transferring images to the intermediate transfer member,

34 for example at 500 volts, which voltage is applied, via

35 mounting fitting 106 to conductive layer 114. Thus, the

36 source of transfer voltage is very near the outer surface of 1 portion 104 which allows for a lower transfer potential on

2 the drum.

3 In a preferred embodiment of the invention, Transfer

4 portion 104 is fabricated by the following procedure:

5 1- The starting structure for blanket construction is a

6 blanket body 116 generally similar to that generally used

7 for printing blankets. One suitable body is MCC-1129-02

8 manufactured and sold by Reeves SpA, Lodi Vecchio (Milano),

9 Italy. Other preferred blanket types are described in US

10 Patents 5,047,808; 4,984,025; 5,335,054 and PCT publications

11 WO 91/03007; WO 91/14393; WO 90/14619; and WO 90/04216,

12 which are incorporated herein by reference. In a preferred

13 embodiment of the invention, body 116 comprises a fabric

14 layer 122, preferably of woven NOMEX material and having a

15 thickness of about 200 micrometers, a compressible layer

16 120, preferably comprising about 400 micrometers of

17 saturated nitrile rubber loaded with carbon black to

18 increase its thermal conductivity. Layer 120 preferably

19 contains small voids (about 40 - 60 % by volume) and a top

20 layer 118 preferably comprised of the same material as the

21 compressible layer, but without voids. Layer 109 is

22 preferably about 100 micrometers thick. The blanket body is

23 produced by manufacturing methods as are generally used for

24 the production of offset printing blankets for ink offset

25 printing.

26 Blanket body 116 is preferably sized to a relatively

27 exact thickness by abrading portions of the surface of top

28 layer 118. A preferred thickness for the finished body 116

29 is about 700 micrometers, although other thicknesses are

30 useful, depending on the geometry of the printing system in

31 which it is used and the exact materials used in the blanket

32 body.

33 2- The fabric side of blanket body 116 is preferably

34 coated with a 30 micrometer thick coating of silicone based

35 adhesive (preferably, Type D 66 manufactured by Dow

36 Corning). The adhesive is covered with a sheet of mylar 1 coated with a fluorosilicone material, such as DP 5648

2 Release Paper (one side coat) distributed by H.P. Smith

3 Inc., Bedford Park, IL. This adhesive is characterized by

4 its good bond to the surface of drum 102 and is resistant to

5 the carrier liquid used in the liquid toner. The blanket may

6 be removed from the drum, when its replacement is desired,

7 by cutting the blanket along the edge of fitting 106 and

8 removing the blanket and fitting.

9 An adhesive is used to assure good thermal contact

10 between the back of the blanket and the drum on which it is

11 mounted. A silicone adhesive is used since adhesives

12 normally used in attachment of blankets deteriorate under

13 the heat which is generated in the underlying drum in the

14 preferred apparatus. While the temperature of the drum

15 varies, depending on the thermal resistance of the blanket

16 and the desired surface temperature of the blanket (which in

17 turn depends on the toner used in the process and the

18 details of transfer of the toner to the final substrate),

19 the drum temperature may reach 80^βC, 100°C, 120°C or 150^βC

20 or more.

21 3- Top layer 118 is preferably coated with a sub-micron

22 layer of primer before being coated with additional layers.

23 A preferred primer is Dow Corning 1205 Prime Coat. The type

24 of primer depends on the properties of the top layer and of

25 the conductive layer. Preferably, 0.3 micron of primer is

26 coated onto a clean top layer with a No. 0 bar in a wire-rod

27 coating apparatus and is allowed to dry before applying the

28 conductive layer.

29 4- Since blanket body 116 may contain materials such as

30 anti-oxidants, anti-ozonants or other additives which may

31 migrate through the upper layers of the blanket, for example

32 as a gas when the blanket is heated during the imaging

33 process and/or in the presence of carrier liquid such as

34 Isopar L, barrier layer 115 is preferably coated onto top

35 layer 118 (or more exactly onto the primer). This barrier

36 layer should be substantially impervious to such materials 1 in the blanket body which may migrate and/or to the carrier

2 liquid which is used .

3 If this layer is omitted, under certain circumstances

4 the additive materials can cause deterioration of the

5 photoreceptor . In particular, it was found that the imaging

6 process may become humidity dependent .

7 In a preferred embodiment of the invention , a 4 - 11

8 micrometer layer of polyvinyl alcohol ( 88% hydrolyzed ) is

9 coated onto the primer layer covering top layer 118.

10 Polyvinyl alcohol , 88% hydrolyzed , having an average

11 molecular weight preferably between 85 , 000 and 145 , 000

12 ( Aldrich Chemical Co . Inc . , Milwaukee, WI ) is dissolved in

13 water at 90 ° C by continuously stirring the mixture in a

14 reflux system for 30 minutes . After 30 minutes , a quantity

15 of ethanol equal to twice the quantity of water is added to

16 the solution, the resulting polyvinyl alcohol concentration

17 being preferably less than 10% . Higher concentration

18 solutions can be used ; however , they give a more viscous

19 solution which is hard to spread evenly.

20 The solution is deposited on layer 118 of body 116

21 using a fine wire rod or knife inclined at 30-45 ° to the

22 direction of movement of the knife or body. The solvent is

23 evaporated either by drying at room temperature or by

24 blowing hot air on the layer.

25 One or more coating passes are employed to give the

26 required thickness .

27 Too thin a layer will result in some trans fer of

28 material from body 116 , which has been correlated with

29 reduced transfer ef f iciency from the photoreceptor to the

30 intermediate transfer blanket , which is believed to be

31 caused by photoreceptor deteriorat ion . Whi le f our

32 micrometers of material appears to be suf ficient to avoid

33 leaching, a somewhat larger thickness is preferably used .

34 Other barrier materials and other thicknesses may be

35 used depending on the carrier liquid used for the toner or

36 the gasses omitted by body 116. Other barrier materials may 1 require lesser or greater thickness depending on their

2 resistance to the carrier liquid or the gasses released by

3 body 116. Alternatively, if body 116 resists leaching by the

4 carrier liquid or does not contain materials which are

5 released ( especially when body 116 is heated ) or any anti-

6 oxidants and/or anti-ozonants, layer 115 may be omitted.

7 Polyvinyl alcohol is a thermoplastic crystall ine

8 material having a melting point which is higher than the

9 temperature of the blanket during operation . Polyvinyl

10 alcohol is also believed to form a layer which is impervious

11 to gasses and to the hydrocarbon carrier liquid used in the

12 liquid toner.

13 5- Conductive layer 114 is preferably formed of acrylic

14 rubber loaded with conductive carbon black. In a preferred

15 embodiment of the invention, only 2-3 micrometers of

16 conductive coating are required. The conductive layer is

17 formed by first compounding 300 grams of Hytemp 4051EP (Zeon

18 Chemicals) with 6 grams of Hytemp NPC 50 and 9 grams of

19 sodium stearate in a two-roll mill for 20 minutes; and then

20 dissolving 150 grams of the compounded material in 2000

21 grams of methyl ethyl ketone (MEK) by stirring for 12 hours

22 at room temperature.

23 40 grams of conductive carbon black, such as, for

24 example, Printex XE2 (Degussa) are added to the solution and

25 the mixture is ground in a 01 attritor (Union Process)

26 loaded with 3/16" steel balls. Grinding proceeds at 10°C for

27 4 hours after which time the material is diluted by the

28 addition of MEK to a concentration of 7.5-8% solids and

29 discharged from the grinder in the form of a conductive

30 lacquer.

31 The blanket (after step 3 or step 4) is overcoated with

32 about 3 micrometers of the conductive lacquer (three passes

33 using a No. 0 rod) and allowed to dry for 5 minutes at room

34 temperature.

35 An additional coating of primer is added over the

36 conductive lacquer (except for the portion which is to be 1 inserted into bar 108 ) before the soft elastomeric

2 conforming layer is applied.

3 The resistance of the conductive layer should

4 preferably be more than about 20 kohms/square and preferably

5 less than about 50 kohm/square. This value will depend on

6 the resistivity of the layers above the conducting layer and

7 on the aspect ratio of the blanket. In general, the

8 resistance should be low enough so that the current flowing

9 on the conducting layer (to supply leakage current through

10 the overlying layers ) should not cause a substantial

11 variation of voltage along the surface of the blanket. The

12 resistance of the conducting layer and, more importantly,

13 the resistance of the overlying layers control the current

14 flowing through the overlying layers. Generally speaking,

15 the conductive layer has a relatively low resistance and

16 resistivity, the conforming layer (layer 111) has a higher

17 resistivity and the overlying release layer (layer 109 ) has

18 a still higher resistivity.

19 6- One kg of pre-filtered Fomrez-50 polyester resin

20 (Hagalil Company, Ashdod, Israel) is dehydrated and degassed

21 under vacuum at 60^βC. 600 grams of the degassed material is

22 mixed with 1.4 grams of di-butyl-tin-diluarate (Aldrich) and

23 degassed at room temperature for 2 hours. 30 grams of the

24 resulting material, 3.15 grams of RTV Silicone 118 (General

25 Electric) and 4.5 grams of Polyurethane cross-linker,

26 DESMODUR 44V20 (Bayer) are stirred together. A 100

27 micrometer layer of the material is coated over the primed

28 conductive layer using a No. 3 wire rod with several passes

29 under clean conditions, preferably, class 100 conditions.

30 The coating is cured for two hours at room temperature under

31 a clean hood to form a polyurethane layer.

32 Other methods of forming suitable conforming layers are

33 shown and described in the parents of this application.

34 Alternatively, the conductive layer may be omitted and layer

35 118 made conductive.

36 Layer 111 which is thus formed should have a resistance 1 of the order of about 10⁹ ohm-cm, good thermal stability at

2 the working temperature of the blanket surface, which is

3 preferably about 100°C or less.

4 The function of the conforming layer is to provide good

5 conformation of the blanket to the image forming surface

6 (and the image on the image forming surface) at the low

7 pressures used in transfer of the image from the image

8 forming surface to the blanket. The layer should have a

9 Shore A hardness preferably of between 25 or 30 and 65, more

10 preferably about 50. While a thickness of 100 micrometers is

11 preferred, other thicknesses, between 50 micrometers and 300

12 micrometers can be used, with 75 to 125 micrometers being

13 preferred.

14 7- 12 grams of RTV silicone 236 (Dow Corning) release

15 material preferably diluted with 2 grams of Isopar L (Exxon)

16 and 0.72 grams of Syl-off 297 (Dow Corning) are mixed

17 together. A wire rod (bar No. 1) coating system is used,

18 with five or six passes, under clean conditions to achieve

19 an 8 micrometer release layer thickness. The material is

20 cured at 140"C for two hours. The cured release material has

21 a resistivity of approximately 10¹ to 10¹⁵ ohm-cm.

22 In order to mount blanket 100 on drum 102, mounting

23 legs 110 are inserted into a plurality of mounting holes 130

24 formed in drum 102, preferably without removing the mylar

25 sheet from the adhesive layer (the back of the blanket). As

26 can be seen most clearly in Fig. 3A, 3B and 4D, mounting

27 legs 110 each have a tip portion 132 and a back portion 134.

28 Tips 132 are inserted into slots formed in the far sidewalls

29 of mounting holes 130 and the back portion 134 rests against

30 the opposite sidewall of the hole. In this way the end of

31 the blanket is accurately positioned. The edge of the mylar

32 sheet closest to the legs is removed and the remainder of

33 the mylar sheet is progressively removed while making sure

34 that the successive portions of the blanket which are thus

35 attached to the drum by the adhesive lie flat against the

36 drum. 1 The present inventors have found that this method of

2 mounting is far superior to either adhesive mounting alone

3 or to grippers at both ends of the blanket in providing a

4 stable transfer surface.

5 As an alternative to, or additional to, the adhesive

6 layer 126, a very soft conforming layer may be used at the

7 back of the blanket. A soft layer of this type will allow

8 for good thermal contact between the blanket and the heated

9 drum 102 so that the temperature of the drum need not be

10 excessive in order for the outer surface of the blanket to

11 reach its operating temperature. Furthermore, such a very

12 soft layer will cause the blanket to "cling" to the drum

13 obviating the use of adhesive under certain circumstances.

14 Furthermore, when the blanket is replaced there is no

15 adhesive residue on the drum to be removed.

16 A very soft layer may be produced by the following

17 method:

18 1- lOOg of Hi-Temp 4051 EP (Zeon) acrylic resin is

19 mixed with 2g NPC-50 crosslinker (Zeon) and 3g sodium

20 stearate and dissolved in toluene to give a solution of 15%

21 non-volatile solids. Optionally, up to about 40g of carbon

22 black Pearls 130 (Cabot) is added.

23 2- A thin layer of the solution is coated onto release

24 coated mylar and dried. This process is repeated several

25 times until a thickness of preferably 20-30 micrometers is

26 achieved.

27 3- The uncured resin is laminated to the adhesive

28 layer of a blanket produced in accordance with the

29 invention, or directly to the fabric layer. This step is

30 preferably carried out prior to the cure of the release

31 layer.

32 4- The laminated structure is cured together with the

33 release layer and the release coated mylar is removed.

34 The layer has a Shore A hardness of about 20-24

35 without carbon black and about 40-45 with carbon black.

36 Softer materials are also suitable; however, substantially 1 harder materials do not adhere well to the drum surface.

2 Optionally, the adhesive layer at the trailing end of the

3 blanket is not coated with the very soft layer to improve

4 coherence of the blanket and the drum. This is especially

5 desirable for harder layers.

6 The acrylic material may be replaced by other soft

7 elastomer materials such as soft polyurethane or nitrile

8 rubber. Other heat improving fillers which have a smaller

9 effect on the hardness of the final product may be used

10 instead of carbon black, such as Fe2C>3 or alpha aluminum

11 oxide.

12 Fig. 5 shows an alternative, preferred embodiment of

13 the invention in which somewhat different shaped holes 130'

14 are used. In this embodiment the back portion 134 rests

15 against a protrusion 150 formed on one side of the hole

16 while a surface 154 of leg 110 rests against the bottom 156

17 of a protrusion formed on the other side of the hole.

18 While the preferred electrical connection between the

19 conductive layer and the mounting bar is preferably achieved

20 by removing (or not forming) the layers which overlay an end

21 portion of the conductive layer, piercing the overlying

22 layers, for example, by crimping and/or piercing the

23 mounting bar, for example, at points marked 160 in Fig. 4D.

24 Crimping can also be used to hold the blanket in the

25 mounting bar.

26 While the adhesive layer preferably covers the back of

27 the blanket, alternatively the adhesive layer may cover only

28 a portion of the back such as the edge farthest away from

29 the bracket (the trailing edge of the blanket); or may, for

30 some embodiments of the invention and under certain

31 circumstances, be omitted.

32 It should be understood that some aspects of the

33 invention are not limited to the specific type of image

34 forming system used and some aspects of the present

35 invention are also useful with any suitable imaging system

36 which forms a liquid toner image on an image forming surface 1 and, for some aspects of the invention, with powder toner

2 systems. Some aspects of the invention are also useful in

3 systems such as those using other types of intermediate

4 transfer members such as belt or continuous coated drum type

5 transfer members. Some aspects of the invention are suitable

6 for use with offset printing systems. The specific details

7 given above for the image forming system are included as

8 part of a best mode of carrying out the invention; however,

9 many aspects of the invention are applicable to a wide range

10 of systems as known in the art for electrophotographic and

11 offset printing and copying.

12 It will be appreciated by persons skilled in the art

13 that the present invention is not limited by the description

14 and example provided hereinabove. Rather, the scope of this

15 invention is defined only by the claims which follow: 16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

Claims

1 CLAIMS

2 1. Imaging apparatus comprising:

3 an imaging surface having a toner image formed thereon;

4 and

5 an intermediate transfer member, which receives the

6 toner image from the imaging surface and from which it is

7 subsequently transferred, comprising:

8 a drum having mounting recesses formed therein; and

9 an intermediate transfer blanket mounted on the

10 drum, the blanket comprising:

11 a layered transfer portion having a transfer

12 surface on one face thereof which receives the toner image;

13 and

14 a mounting fixture, attached to only one edge of

15 the layered transfer portion and adapted to mate with the

16 mounting recesses in the drum,

17 whereby the transfer blanket is removably mounted on

18 the drum. 19

20 2. Apparatus according to claim 1 wherein at least a

21 portion o f a surf ace of the layered trans f er portion

22 opposite to the transfer surface is bonded to the drum. 23

24 3. Apparatus according to claim 1 or claim 2 wherein the

25 layered transfer potion comprises an adhesive layer on a

26 second face thereof opposite the transfer surface. 27

28 4. Apparatus according to any of the preceding claims

29 wherein the l ayered trans f er portion compri ses an

30 electrically conductive layer underlying the transfer

31 surface; and

32 wherein the mounting fixture comprises an electrically

33 jq-αnductive element , attached to one edge of the transfer

³⁴

which is electrically connected to the electrically

35 cofclgtøctive layer. 36 1 5. Apparatus according to claim 4 wherein the electrically

2 conductive element contacts the drum and wherein the drum is

3 electrified to a voltage which is operative to transfer the

4 toner image from the imaging surface to the transfer

5 surface. 6

7 6. Apparatus according to claim 4 wherein the electrically

8 conductive element comprises at least one "L" shaped finger-

9 like extension extending therefrom. 10

11 7. Apparatus according to claim 6 wherein said at least

12 one "L" shaped extension has a first portion extending in a

13 direction perpendicular to the layered transfer portion and

14 a second portion attached and substantially perpendicular

15 to the first portion and extending substantially parallel to

16 and away from the layered transfer portion. 17

18 8. Apparatus according to claim 7 wherein said mounting

19 recesses further comprise recesses therein which receive

20 said second portion. 21

22 9. A substantially rectangular intermediate transfer

23 blanket comprising:

24 a layered transfer portion having a transfer surface on

25 one face thereof; and

26 a mounting fixture, adapted for mounting the blanket on

27 a drum, attached to only one edge of the layered transfer

28 portion. 29

30 10. An intermediate transfer blanket according to claim 9

31 wherein the layered trans fer portion comprises an

32 electrically conductive layer underlying the transfer

33 surface; and

34 wherein the mounting fixture comprises an electrically

35 conductive element , attached to one edge of the transfer

36 portion, which is electrically connected to the electrically 1 conductive layer. 2

3 11. A substantially rectangular intermediate transfer

4 blanket comprising:

5 a layered transfer portion having a transfer surface on

6 one face and including an electrically conductive layer

7 underlying the transfer surface; and

8 an electrically conductive element , attached to one

9 edge of the trans fer portion , which i s electrical ly 10 connected to the conducting layer.

11

12 12. An intermediate transfer blanket according to claim 10

13 or claim 11 wherein the conductive element comprises at

14 least one "L" shaped finger-like extension extending

15 therefrom. 16

17 13. An intermediate transfer blanket according to claim 12

18 wherein said at least one "L" shaped extension has a first

19 portion extending in a direction perpendicular to the

20 layered transfer portion and a second portion attached and

21 substantially perpendicular to the first portion extending

22 away from the layered transfer portion. 23

24 14. An intermediate transfer blanket according to any of

25 claims 9-13 wherein the layered transfer portion comprises a

26 conformal layer formed of a material having a Shore A

27 hardness of less than 65. 28

29 15. A layered intermediate transfer member comprising:

30 an outermost transfer surface; and

31 a conforming layer operatively associated with the

32 transfer surface and having a shore A hardness of less than

33 about 65. 34

35 16. A substantially rectangular intermediate transfer

36 member according to claim 15. 1

2 17. An intermediate transfer member according to any of

3 claims 14-16 wherein said conforming layer has a Shore A

4 hardness of less than about 50. 5

6 18. An intermediate transfer member according to any of

7 claims 14-17 wherein said conforming layer has a Shore A

8 hardness of more than about 30. 9

10 19. An intermediate transfer member according to claim 18

11 wherein said conforming layer has a Shore A hardness of more

12 than about 35. 13

14 20. An intermediate transfer blanket according to any of

15 claims 9-19 wherein the layered transfer portion comprises a

16 soft layer, having a Shore A hardness of less than 90, on

17 the surface of the layered transfer portion opposite to the

18 transfer surface. 19

20 21. A layered intermediate transfer blanket comprising:

21 an transfer surface on one face of the blanket; and

22 a soft layer on the opposite face of the blanket which

23 has a Shore A hardness of less than 90. 24

25 22. An intermediate transfer member according to claim 20

26 or claim 21 wherein the soft layer has a Shore A hardness of

27 less than about 45. 28

29 23. An intermediate transfer member according to claim 20

30 or claim 23 wherein the soft layer has a Shore A hardness of

31 less than about 25. 32

33 24. An intermediate transfer member according to claim 20

34 or claim 23 wherein the soft layer has a Shore A hardness of

35 about 45. 36 1 25. An intermediate transfer blanket according to any of

2 claims 20-24 wherein the soft layer comprises an acrylic

3 elastomer. 4

5 26. An intermediate transfer member according to any of

6 claims 9-19 and including:

7 an adhesive layer on the opposite face of the blanket

8 from the transfer surface. 9

10 27. An intermediate transfer member according to claim 26

11 wherein the adhesive layer is stable at a temperature of at

12 least 80°C. 13

14 28. A layered intermediate transfer blanket comprising:

15 an transfer surface on one face of the blanket; and

16 an adhesive layer on the opposite face of the blanket

17 which is stable at a temperature of at least 80^βC. 18

19 29. An intermediate transfer blanket according to any of

20 claims 26-28 wherein the adhesive layer is stable at a

21 temperature above 100°C. 22

23 30. An intermediate transfer blanket according to claim 29

24 wherein the adhesive layer is stable at a temperature above

25 120°C. 26

27 31. An intermediate transfer blanket according to claim 29

28 wherein the adhesive layer is stable at a temperature above

29 150°C. 30

31 32. Am intermediate transfer member according to any of

32 claims 9-31 and including:

33 a resilient layer underlying the transfer surface; and

34 a barrier layer that is substantially impervious to

35 l iquid hydrocarbons and i s situated intermediate the

36 resilient layer and the transfer surface . 1

2 33. A layered intermediate transfer member, comprising:

3 a transfer surface;

4 a resilient layer underlying the transfer surface; and

5 a barrier layer that is substantially impervious to

6 liquid hydrocarbons and is situated intermediate the

7 resilient layer and the transfer surface. 8

9 34. An intermediate transfer member according to claim 32

10 or claim 33 wherein the resilient layer comprises a material

11 which is at least partly leachable by the liquid

12 hydrocarbon. 13

14 35. An intermediate transfer member according to any of

15 claims 32-34 wherein the member is adapted for the transfer

16 of liquid toner images comprising toner particles and

17 carrier liquid and wherein the liquid hydrocarbon is said

18 carrier liquid. 19

20 36. An intermediate transfer member according to any of

21 claims 9-31 and including:

22 a resilient layer underlying the transfer surface; and

23 a barrier layer that is substantially impervious to

24 gases and is situated intermediate the resilient layer and

25 the transfer surface. 26

27 37. A layered intermediate transfer member, comprising:

28 a transfer surface;

29 a resilient layer underlying the transfer surface which

30 releases gases; and

31 a barrier layer that is substantially impervious to the

32 gasses and is situated intermediate the resilient layer and

33 the transfer surface. 34

35 38. An transfer member according to any of claims 31-37

36 wherein the barrier layer comprises at least partially 1 hydrolyzed polyvinyl alcohol. 2

3 39. An intermediate transfer member comprising:

4 a conductive layer having a relatively low electrical

5 resistivity;

6 an outer layer having a relatively high electrical

7 resistivity; and

8 a third layer intermediate the conductive and outer

9 layers having an electrical resistivity intermediate the 10 relatively low and relatively high electrical resistivities. 11

12 40. An intermediate transfer member according to claim 39

13 wherein the third layer is a conforming layer having a Shore

14 A hardness of less than about 65. 15

16 41. An intermediate transfer member according to any of

17 claims 9-40 wherein the outer layer is a release layer for

18 toner. 19

20 42. Imaging apparatus for performing an imaging process,

21 comprising:

22 an imagi ng sur f ace having a l iqu id toner image

23 compri s ing toner part icles and carrier l iqu id f ormed

24 thereon; and

25 an intermediate transfer member according to any of

26 claims 9-31 , which receives the toner image from the imaging

27 surface and from which it is subsequently transferred . 28

29 43. Imaging apparatus for performing an imaging process ,

30 comprising:

31 an imaging surface having a liquid toner image

32 comprising toner particles and carrier liquid formed

33 thereon; and

34 an intermediate transfer member, which receives the

35 toner image from the imaging surface and from which it is 36^subsequently transferred, comprising: 1 a layered transfer portion having a transfer

2 surface on one face thereof which receives the toner image;

3 a resilient layer underlying the transfer surface

4 which comprises a material which interferes with the

5 operation of the imaging process;

6 a barrier layer that is substantially impervious

7 to the interfering material comprised in the resilient layer

8 and is situated intermediate the resilient layer and the

9 transfer surface. 10

11 44. Imaging apparatus according to claim 43 wherein the

12 barrier layer comprises at least partially hydrolyzed

13 polyvinyl alcohol. 14

15 45. Imaging apparatus according to claim 43 or claim 44

16 wherein the barrier layer is a barrier layer for gasses. 17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35. _

3 'l.