JP2004317859A - Excessive solvent removing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent reduction in solvent recovering ability when an elastic porous layer of a squeezing roller is deteriorated and to surely carry out solvent recovery in high speed rotation. <P>SOLUTION: The squeezing roller 15 consists of an inner cylinder 17 with one part of a periphery wall in the circumferential direction made to be a blind patch and the other part a porous constitution and an outer cylinder 17 with the whole periphery wall made to be the porous constitution and is provided with the elastic porous layer on its outer periphery side and fit into the inner cylinder to be freely rotated. The inner cylinder is fixed to a supporting stand to have its angle freely adjusted so that the blind part of the inner cylinder is face to an image carrier side and also in the rotating direction. A rotating drive means is connected to the outer cylinder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is used in a wet electrophotographic printing machine in which a toner image is developed on the surface of a latent image holding member with a liquid toner, and a developing device for removing an excess solvent on the surface of the latent image holding member. The present invention relates to a device for removing excess solvent provided downstream of the apparatus.
[0002]
[Prior art]
The above-mentioned wet electrophotographic printing machine is disclosed in, for example, Japanese Patent Application Laid-Open No. H11-157, and is arranged around a latent image holding member (photosensitive drum) from a rolling contact portion between the latent image holding member and an intermediate transfer member in a rotation direction downstream side. A plurality of sets of image forming means including a charger, an exposing device, and a developing device, and removing excess solvent for removing the solvent remaining on the surface of the latent image holding member that has passed through the image forming means at the most downstream side thereof. Means are arranged.
[0003]
The conventional excess solvent removing means is as shown in FIG. 7, in which a shielding cylinder a made of a non-permeable material is used as a core, and an elastic porous layer b is fixed to the outside of the shielding cylinder a. The squeezing roller d composed of the outer cylinder c having a porous structure is rolled and brought into contact with the latent image holding member e. The shielding cylinder a has a notch-shaped vent f opposed to the inner surface of the outer cylinder c of the aperture roller d at a position shifted in the rotational direction from the position of the aperture roller d facing the latent image holding member d. Is provided, and a pressure reducing device such as a vacuum pump is connected to the vent f.
[0004]
Then, the solvent absorbed from the surface of the latent image holding member e by the elastic porous layer b of the squeezing roller d rotating in synchronization with the latent image holding member e is separated from the portion facing the latent image holding member e. At the position, the excess solvent g of the latent image holder e is sucked through the vent f and the excess solvent g is squeezed and collected without being affected by the suction force from the vent f.
[0005]
[Patent Document 1]
JP-A-2002-23504 (paragraphs 0044 to 0048, FIG. 3)
[0006]
[Problems to be solved by the invention]
In the above-described conventional excess solvent removing device, the portion of the squeezing roller d facing the latent image holding member e is shielded, so that the solvent is removed from the surface of the latent image holding member on the outer peripheral portion of the squeezing roller d. Since the absorption is performed only by the absorption power of the elastic porous layer d, if the absorption power of the elastic porous layer d decreases due to the clogging or deterioration, the solvent cannot be recovered.
[0007]
Further, in order to increase the suction force inside the squeezing roller d, the shielding section by the shielding cylinder a is long, and thus the opening width of the ventilation port f is reduced. There is a problem that the suction of the solvent through the vent f cannot be made in time.
[0008]
The present invention has been made in view of the above, and even if the elastic porous layer provided on the outer periphery of the squeezing roller deteriorates due to clogging or the like, it is possible to prevent the recovery power of the excess solvent from the latent image holding member from being reduced. It is another object of the present invention to provide a surplus solvent removing device capable of surely collecting a surplus medium even under high-speed rotation.
[0009]
In order to achieve the above object, a surplus medium removing device according to the present invention is a developing device for a wet type electrophotographic printing machine that develops a toner image on the surface of a latent image holding member using a developing device using liquid toner. In an excess solvent removing device provided on the downstream side so as to face the latent image holding member surface, an inner cylinder in which a part of the peripheral wall in the circumferential direction is blinded and the other part is made porous, and an entire peripheral wall of the peripheral wall And a squeezing roller comprising an outer cylinder rotatably fitted to the inner cylinder with an elastic porous layer provided on the outer peripheral side and an inner cylinder, and a blind-shaped portion of the inner cylinder. Are fixed to a support table so as to face the latent image holding member and to be angle-adjustable in the rotation direction, and a rotation driving means is connected to the outer cylinder. The support base is configured to be movable in a direction in which the elastic porous layer of the squeezing roller comes into contact with and separate from the latent image holding member, and a doctor blade contacts the elastic porous layer of the squeezing roller. A solvent receiver was provided below the squeezing roller.
[0010]
[Operation]
According to this configuration, the squeezing roller moves to the squeezing position where the elastic porous layer contacts the latent image holding member and rotates the outer cylinder provided with the elastic porous layer, thereby forming the latent image holding member. The solvent on the surface is squeezed out by the elastic porous layer, and is sucked into the inner cylinder through the porous outer cylinder and the peripheral wall of the inner cylinder by the negative pressure in the inner cylinder.
[0011]
At this time, since the blind member is provided in a portion of the inner cylinder facing the latent image holding member, the elastic porous layer in a portion facing the latent image holding member and in contact with the latent image holding member is provided from the inner cylinder. No negative pressure is applied. Therefore, the solvent on the surface of the latent image carrier is absorbed only by the contact or pressing action of the elastic porous layer, and the toner image on the surface of the latent image carrier is not transferred to the elastic porous layer side.
[0012]
In the above operation, when the elastic porous layer is clogged or degraded and the solvent absorbing power of the elastic porous layer is reduced, the solvent cannot be recovered from the surface of the latent image holding member. The cylinder is angularly displaced in the rotation direction of the outer cylinder to shift the position of the blind portion in the circumferential direction so that the porous portion of the inner cylinder is closer to the opposing portion between the elastic porous layer and the latent image holding member. As a result, the solvent on the surface of the latent image holding member is supplementarily sucked by the negative pressure action of the inner cylinder, and the recovering power of the solvent is recovered.
[0013]
Further, in the above operation, the solvent absorbed in the elastic porous layer is sucked toward the inner cylinder side in the entire region of the cylindrical portion outside the blind portion. Since the area of the porous component of the inner cylinder is larger than that of the blind part, the suction range of the inner cylinder becomes longer in the circumferential direction, and even under high-speed rotation, the solvent can be reliably collected by the squeezing roller. It can be carried out.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a main part of a wet electrophotographic printing machine provided with a surplus solvent removing device 1 according to the present invention, and a photosensitive drum 2 which is an example of a latent image holding member is surrounded by an intermediate transfer roller 3 A photoconductor drum cleaner device 4, a static elimination device 5, a plurality of sets, for example, first and second image forming devices 6a and 6b, and a drying device 7, The surplus medium removing device 1 is disposed between the most downstream image forming device 6 b and the drying device 7.
[0015]
The wet type electrophotographic printing machine is arranged symmetrically with respect to one location on the peripheral surface of the intermediate transfer roller 3, and the continuous paper W passes between the two intermediate transfer rollers 3, so that double-side printing is performed on the continuous paper W. ing. It is also possible to perform one-sided printing by rolling the impression cylinder against the intermediate transfer roller 3.
[0016]
The image forming apparatuses 6a and 6b of each set have substantially the same configuration, and a charger device 8, an exposure device (latent image forming device) 9, a developing device 10, and a squeeze roller 11 are arranged from the upstream side in the rotation direction of the photosensitive drum 2 in the rotation direction. They are arranged in order.
[0017]
In this wet electrophotographic printing machine, the toner and the potential remaining on the surface of the photosensitive drum 2 are removed by the photosensitive drum cleaning device 4 and the charge removing device 5 as the photosensitive drum 2 rotates. Next, two color toner images are formed by the first and second image forming apparatuses 6a and 6b.
[0018]
At this time, in each of the image forming apparatuses 6a and 6b, the surface of the photosensitive drum 2 is charged to a predetermined voltage by the charger device 8, and the surface of the photosensitive drum 2 is irradiated with a laser beam image-modulated by the exposure device 9 to be statically charged. An electrostatic latent image is formed, and this electrostatic latent image is developed into a toner image by the developing device 10. Then, the developing toner at this time is supplied to the surface of the photosensitive drum 2 together with the solvent. Excess solvent at this time is removed by the squeeze roller 11.
In such a wet electrophotographic printing machine, the excess medium cannot be completely removed by the squeeze roller 11 in each of the image forming apparatuses 6a and 6b, and the surface of the photosensitive drum 2 that has passed through both the image forming apparatuses 6a and 6b is still dried by the drying apparatus 7. There are surplus media that cannot be completely removed. The excess solvent removing device 1 according to the present invention is for removing excess solvent present downstream of the image forming devices 6a and 6b.
[0020]
Hereinafter, the configuration of the excess solvent removing device 1 will be described with reference to FIGS.
[0021]
In the figure, reference numeral 15 denotes an aperture roller which comes into contact with the photosensitive drum 2 and rotates in the opposite direction (the same circumferential direction). The squeezing roller 15 is rotatably and tightly fitted on the outer side of the inner cylinder 17 having both end shafts supported by brackets 16a and 16b, and has an elastic porous layer, for example, a sponge layer 18, on the outer periphery. It comprises a laminated outer cylinder 19. The outer cylinder 19 has a porous structure having a large number of small holes 20 all around its peripheral wall. In addition, on the peripheral wall of the inner cylinder 17, a portion of the squeeze roller 16 in contact with the photoconductor drum 2, that is, a portion facing the photoconductor drum 2 is a blind portion 17a over a predetermined angle θ in the circumferential direction. The other peripheral wall has a porous structure in which many small holes 21 are provided over the entire length. The angle θ of the blind portion 17a is about 90 degrees and is provided over the entire length.
[0022]
Shafts 22a and 22b projecting from both ends of the inner cylinder 17 are fixed to the brackets 16a and 16b so as to be angularly displaceable in the rotation direction. A passage 24 communicating with the inner hollow portion of the inner cylinder 17 is provided at the axis of one shaft 22a, and this passage 24 is connected to a suction device (not shown) via a pipe 25 connected to an end of the shaft 22a. Are in communication.
[0023]
Both ends of the outer cylinder 19 are rotatably supported by the shafts 22a and 22b of the inner cylinder 17, and a pulley 26a is fixed to one end. The pulley 26a is fixed to the output shaft of the drive motor 27. A belt 29 is wound around 26b, and the outer cylinder 19 is rotated by the drive motor 27 in a direction opposite to that of the photosensitive drum 2, that is, so that the contact peripheral surface runs in the same direction.
[0024]
Brackets 16a and 16b for fixedly supporting the cylinder 17 are supported by a support base 28. Brackets 30a, 30b provided at both ends of the support base 28 are supported by guide rods 32a, 32b provided on the front and rear frames 31a, 31b so as to be movable in the direction of separation and contact with the photosensitive drum 2. . The drive motor 27 is coupled to the support base 28 via a support arm 33 so as to be movable in the direction of adjusting the tension of the belt 29.
[0025]
Further, the support base 28 is provided with a dish-shaped solvent receiver 34 for receiving the solvent dripped from the sponge layer 18 of the squeeze roller 15. The solvent receiver 34 is provided on the surface of the sponge layer 18 of the squeeze roller 15. Is provided so as to be movable in the contact direction.
[0026]
The brackets 30a, 30b at both ends of the support base 28 are provided with grooves 36, 36 in a direction perpendicular to the moving direction thereof. Further, on both sides of the support base 28, cylinder devices 37, 37 which operate in the movement direction of the support base 28 are fixedly provided on the frames 31a, 31b, and are turned around the piston rod in a direction perpendicular to the axis. Moving locking pieces 38a and 38b are provided. When the locking pieces 38a, 38b are pivoted toward the brackets 30a, 30b of the support base 28, they engage with the grooves 36, 36 thereof.
[0027]
The positional relationship between the locking pieces 38a, 38b provided on the cylinder devices 37, 37 and their piston rods and the grooves 36, 36 with which they are engaged is determined by the fact that the sponge layer 18 of the squeezing roller 15 has a predetermined pressure (deformation amount). The locking pieces 38a, 38b engage with the grooves 36, 36 in a range of a standby position in which this portion is separated by a predetermined distance (for example, 7 mm) from the throttle position in contact with the photosensitive drum 2 in (2). Thus, the cylinder devices 37, 37 extend and contract over this range. 39, 39 are stoppers 10 for setting the moving end of the squeeze roller 15 toward the photosensitive drum 2, and the set position is variable.
[0028]
The squeezing roller 15 can be moved to a maintenance position where the squeezing roller 15 is separated from the photosensitive drum 2 by a distance greater than the contact / separation stroke, and the cylinder device 37 is moved to a position corresponding to the groove 36 of the one bracket 30b at the end. Another locking piece 38c having the same function as the locking piece 38b provided on the piston rod is provided in the groove 36 so as to be detachable.
[0029]
The operation of the surplus solvent removing device 1 having the above configuration will be described below.
The squeezing roller 15 of the excess solvent removing device 1 is manually moved along the guide rods 32a and 32b between a position where the sponge layer 18 is close to the surface of the photosensitive drum 2 and a maintenance position where the sponge layer 18 is largely separated from this position. Be moved.
[0030]
Then, the squeezing roller 15 is moved to a position close to the photosensitive drum 2, and the locking pieces 37 a and 37 b are rotated and engaged with the grooves 36 of the brackets 30 a and 30 b provided at both ends of the support base 28 at this time. Combine. In this state, the squeezing roller 15 is rotated by the drive motor 27, and the cylinder devices 37, 37 are extended to move the squeezing roller 15 to the squeezing position, whereby the sponge layer 18 of the squeezing roller 15 is moved to the photosensitive drum 2. The solvent that is pressed against the surface and adheres to the surface of the photosensitive drum 2 is squeezed out by the sponge layer 18. At this time, since the air in the inner cylinder 17 is sucked by the suction device through the pipe 25 and the inside thereof has a negative pressure, this negative pressure is applied to the outer cylinder through the small holes 20 and 21. The solvent acting on the outer surface of the inner cylinder 19 and being drawn out by the sponge layer 18 is removed from the outer peripheral surface of the outer cylinder 19 in the entire area where the inner cylinder 17 is out of the blind portion 17a, that is, in an area sufficiently larger than the blind portion. It is sucked into the inner cylinder 17 through small holes 20 and 21 provided in the peripheral wall of the outer cylinder 19 and the inner cylinder 17, and then is sucked into the suction device via the pipe 25.
[0031]
At this time, since the blind portion 17a without the small hole 21 is provided on the peripheral wall of the inner cylinder 17 at a position facing the photosensitive drum 2, a portion of the outer cylinder 19 facing the photosensitive drum 2 is provided. The negative pressure from the suction device is not applied to the inner surface of the. For this reason, the above-mentioned suction force is not applied to the sponge layer 18 in the portion in contact with the photosensitive drum 2.
[0032]
Therefore, in the portion of the sponge layer 18 that is in contact with the photosensitive drum 2, no forcible suction force due to the negative pressure acts, and the excess solvent on the surface of the photosensitive drum 2 is absorbed by the liquid absorbing force of the sponge itself. Is done. As described above, this solvent is sucked into the inner cylinder 17 through the small holes 20 and 21 at a position past the blind portion 17a of the inner cylinder 17.
[0033]
For this reason, on the surface of the photosensitive drum 2 where the sponge layer 18 of the squeezing roller 15 is in contact, no suction force due to the negative pressure acts, and only the pressing of the sponge layer 18 causes excess solvent to be removed from the sponge layer 18. , And the toner forming the toner image on the surface of the photosensitive drum 2 is prevented from adsorbing to the sponge layer 18 due to the negative pressure in the squeezing roller 15. Transfer of toner can be prevented.
[0034]
The solvent is sucked by the negative pressure of the inner cylinder 17 when the sponge layer 18 at the part in contact with the photoreceptor drum 2 is located outside the position of the blind portion 17 a of the inner cylinder 17. As a result, since the amount of solvent impregnation is always small in the portion facing the photoconductor drum, the solvent is satisfactorily performed in this portion.
[0035]
When the sponge layer 18 is clogged or deteriorated by the toner in the action of removing the surplus solvent and the liquid absorbing power is reduced, the ability of the squeeze roller 15 to remove the solvent is reduced. .
[0036]
In such a case, as shown in FIG. 3 (b), the inner cylinder 17 is angularly displaced and the position of the blind portion 17a is shifted in the circumferential direction by the displacement angle R, so that the porous structure of the cylinder 17 is changed. The portion is brought closer to the opposing portion between the sponge layer 18 of the outer cylinder 19 and the photosensitive drum 2.
[0037]
As a result, a negative pressure from the inner cylinder 17 acts on a part of the sponge layer 18 in a portion opposed to and in contact with the photosensitive drum 2, and the liquid absorbing force of the sponge layer 18 in this portion is reduced by the negative pressure. The liquid absorbing force due to the pressure is applied to correct the decrease in the liquid absorbing force of the sponge layer 18 itself.
[0038]
The solvent absorbed by the sponge layer 18 and remaining on the sponge layer 18 is scraped off by the doctor 35 according to the rotation of the squeezing roller 15 and received by the solvent receiver 34.
[0039]
The squeeze roller 15 is moved to a standby position separated from the photosensitive drum 2 by shortening the cylinder devices 37, 37, as shown in FIG.
[0040]
Further, by removing the locking pieces 38a, 38b provided on the piston rods of the cylinder devices 37, 37 from the grooves 36, 36 of the brackets 30a, 30b, the squeezing roller 15 is moved from the photosensitive drum 2 as shown in FIG. It is moved to a maintenance position that is greatly separated. At this time, the other locking pieces 38a are locked to the brackets 30a and 30b.
[0041]
In the above-described embodiment, an example in which the sponge layer 18 is laminated on the outer peripheral surface of the outer cylinder 19 has been described, but this is not limited thereto. Any material can be used as long as it can absorb the residual solvent.
[0042]
【The invention's effect】
According to the present invention, the surplus solvent on the surface of the latent image holding member can be removed without the force of the negative pressure acting on the surface of the latent image holding member, and thus without affecting the toner image on the surface of the latent image holding member.
[0043]
Then, when the liquid absorbing force of the elastic porous layer itself of the squeezing roller is reduced due to clogging or deterioration of the squeezing roller, the inner cylinder of the squeezing roller is angularly displaced, whereby the latent image holding member of the elastic porous layer is displaced. A negative pressure is applied to the inside of a part of the opposed portion to prevent the liquid absorbing force due to the negative pressure from acting at the time of assisting. be able to.
[0044]
According to the present invention, the area of the porous component provided on the peripheral wall of the inner cylinder is larger than that of the blind-shaped part provided on a part of the peripheral wall of the inner cylinder. It becomes longer in the circumferential direction, so that the solvent can be reliably recovered by the squeezing roller even under high-speed rotation.
[0045]
Further, by bringing the doctor blade into contact with the liquid absorbing material layer, the solvent remaining on the liquid absorbing material layer and the toner transferred to the surface thereof are scraped off.
[Brief description of the drawings]
FIG. 1 is a schematic structural explanatory view showing a main part of a wet electrophotographic printing machine provided with an excess solvent removing device according to the present invention.
FIG. 2 is a partially broken plan view showing a main part of the present invention.
3A is an enlarged cross-sectional view taken along the line AA in FIG. 2, and FIG.
FIG. 4 is an operation explanatory view showing a standby state.
FIG. 5 is an operation explanatory view showing a maintenance state.
FIG. 6 is an enlarged sectional view taken along the line BB of FIG. 4;
FIG. 7 is a sectional view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Excessive solvent removal apparatus, 2 ... Photoconductor drum (latent image holding body), 3 ... Intermediate transfer roller, 4 ... Photoconductor drum cleaner, 5 ... Electrostatic removal apparatus, 6a, 6b ... Image forming apparatus, 7 ... Drying apparatus, 8: Charger device, 9: Exposure device, 10: Developing device, 11: Squeeze roller, 15: Squeeze roller, 16a 16b: Bracket, 17: Inner cylinder, 17a: Blind portion, 18: Sponge layer (elastic porous layer) , 19 ... outer cylinder, 20, 21 ... small hole, 22a, 22b ... shaft, 24 ... passage, 25 ... piping, 26a, 26b ... pulley, 28 ... support base, 27 ... drive motor, 29 ... belt, 30a, 30b ... Bracket, 31a, 31b ... Frame, 32a, 32b ... Guide rod, 33 ... Support arm, 34 ... Solvent receiver, 35 ... Doctor blade, 36 ... Groove, 37 ... Cylinder device, 38a, 38b 38c ... engaging piece.

Claims (3)

A surplus solvent removing device provided downstream of the developing device of a wet electrophotographic printing machine so as to face the surface of the latent image holding member so that the toner image is developed on the surface of the latent image holding member by a developing device using liquid toner. At
An inner cylinder in which a part of the peripheral wall in the circumferential direction is blinded, and the other part has a porous configuration, and the entire inner peripheral wall has a porous configuration, and an elastic porous layer is provided on the outer peripheral side to form the inner cylinder. A squeezing roller composed of an outer cylinder rotatably fitted to the inner cylinder and supporting the inner cylinder so that the blind portion of the inner cylinder is directed toward the latent image holding member and the angle thereof can be adjusted in the rotation direction. An apparatus for removing excess solvent, wherein the apparatus is fixed to a base and a rotation driving means is connected to the outer cylinder. 2. The apparatus for removing excess solvent according to claim 1, wherein the support is movable in a direction in which the elastic porous layer of the squeezing roller comes into contact with or separates from the latent image holding member. 3. The apparatus according to claim 1, further comprising a doctor blade provided in contact with the elastic porous layer of the squeezing roller, and a solvent receiver provided below the squeezing roller.

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