JP2011175212A - Toner supplying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a liquid toner layer with uniform film thickness in the width direction of a supply roller in a toner supplying device. <P>SOLUTION: A toner supply pan 41 is arranged where a liquid toner T is stored and an anilox roller 32 is immersed in the liquid toner T. In the toner supply pan 41, a toner supply port 58 is arranged on one side of the circumference direction or the anilox roller 32, while a toner blade 43 is arranged on the other side. A bottom wall part 51 of the toner supply pan 41 is bent/curved along the circumferential face in the circumference direction of the anilox roller 32 so that a first clearance S1 between the circumferential face of the anilox roller 32 and an inside wall face 51c on one side is set to be larger than a second clearance S2 between the circumferential face of the anilox roller 32 and an inside wall face 51d on the outer side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toner supply device that supplies stored toner.

  Conventionally, a toner composed of a thermoplastic resin, a pigment, and the like is developed into an electrostatic latent image formed on a photosensitive member using a liquid toner dispersed in a carrier, and is primarily transferred to an intermediate transfer member, and further liquid toner An electrophotographic printing apparatus has been proposed in which printing is performed by transferring the toner onto the surface of the printing material and fixing the toner in the transferred liquid toner to the printing material. This electrophotographic printing apparatus develops an electrostatic latent image formed on a photoreceptor with liquid toner, primarily transfers the developed toner image to an intermediate transfer member, and further transfers the developed toner image. In the nip portion with the backup roller to which the bias voltage is applied, printing is performed by transferring the liquid toner on the intermediate transfer member onto the substrate.

  In this electrophotographic printing apparatus, the liquid toner is supplied from the reservoir to the developing roller via the leveling roller by the anilox roller, and from the peripheral surface of the developing roller to the portion where the electrostatic latent image on the photosensitive drum is formed. Transcribed. In this case, a groove or a recess is formed in the peripheral surface of the supply roller, and the liquid toner is carried in the groove or the recess of the supply roller by rotating with a part of the supply roller immersed in the storage portion. The excess liquid toner is scraped off, and the liquid toner carried by the supply roller is supplied to the developing roller that is in contact therewith.

  As such a toner supply device, there is one described in Patent Document 1 below.

JP 2003-066729 A

  In the conventional toner supply device described above, the liquid toner is supplied from the reservoir to the developing roller by the supply roller. The liquid toner remaining on the peripheral surface of the developing roller is scraped off by the blade and is conveyed by the conveying device. Collected in the reservoir. That is, the residual liquid toner is collected and reused. In this case, each roller contacts and supplies the liquid toner to generate heat, and the temperature of the liquid toner rises. When the temperature of the liquid toner rises, the contained toner particles are likely to melt, and it becomes difficult to form a liquid toner layer having a uniform film thickness in the width direction of the supply roller, resulting in a problem that print quality is deteriorated. is there.

  SUMMARY An advantage of some aspects of the invention is that it provides a toner supply device capable of forming a liquid toner layer having a uniform thickness in the width direction of a supply roller.

  To achieve the above object, a toner supply device of the present invention includes a toner supply pan for storing liquid toner, a toner supply unit for supplying liquid toner to the toner supply pan, and a liquid stored in the toner supply pan. A toner supply device comprising: a toner supply roller capable of supplying liquid toner by being partially immersed in toner and rotating; and a toner blade for scraping off excess liquid toner from the toner supply roller. Is provided with the toner supply portion on one side in the circumferential direction of the toner supply roller, the blade on the other side, and an inner wall surface that bends or curves along the circumferential surface of the toner supply roller. A first gap between the peripheral surface of the toner supply roller and the inner wall surface on the one side is the toner supply roller. Said is larger than the second gap between the wall surface in the circumferential surface and the other side of it is characterized in.

  Accordingly, the liquid toner supplied from the toner supply unit to one side of the toner supply pan flows from the first gap side to the second gap side along the circumferential direction of the toner supply roller, but this second gap is narrow. From here, it flows along the axial direction of the toner supply roller. Therefore, in the toner supply pan, the liquid toner circulates in the circumferential direction and the axial direction along the peripheral surface of the toner supply roller, and the contact area between the liquid toner and the peripheral surface of the toner supply roller is increased. Thus, cooling of the liquid toner is promoted, melting of the toner particles is suppressed, and a liquid toner layer having a uniform film thickness can be formed in the width direction of the toner supply roller.

  In the toner supply device of the present invention, a third gap between the peripheral surface of the toner supply roller and the inner wall surface is provided between the first gap and the second gap in the circumferential direction of the toner supply roller. The third gap is set larger than the first gap and the second gap.

  Accordingly, the liquid toner supplied from the toner supply unit to one side of the toner supply pan passes through the third gap wider than the first gap along the circumferential direction of the toner supply roller from the first gap side to the second gap side. Since the third gap is wide, the liquid toner easily flows from the first gap side to the second gap side, and the cooling efficiency of the liquid toner can be improved.

  In the toner supply device of the present invention, the toner supply unit is provided on the one side with respect to the first gap.

  Accordingly, the liquid toner supplied from the toner supply unit to one side of the toner supply pan flows from the wide first gap side to the narrow second gap side, and then flows in the axial direction of the toner supply roller. Circulation efficiency can be improved.

  In the toner supply device of the present invention, a plurality of the toner supply units are provided at equal intervals in the axial direction of the toner supply roller.

  Accordingly, the liquid toner supplied from the toner supply unit to one side of the toner supply pan flows almost uniformly in the axial direction of the toner supply roller, and a liquid toner layer having a uniform film thickness is formed in the width direction of the toner supply roller. Can be formed.

  The toner supply device of the present invention is characterized in that a toner collection pan for receiving liquid toner overflowed from the one side of the toner supply pan is provided below the toner supply pan.

  Accordingly, by overflowing the liquid toner in the toner supply pan from one side of the toner supply pan, the circulation performance of the liquid toner in the toner supply pan can be improved, and the circulation efficiency of the liquid toner can be improved.

  In the toner supply device of the present invention, the toner supply pan is provided with a discharge port at the bottom for discharging the liquid toner to the toner recovery pan.

  Therefore, when the supply of the liquid toner becomes unnecessary, the liquid toner in the toner supply pan can be discharged from the discharge port to the toner collection pan, and the deterioration of the quality of the liquid toner due to being left can be suppressed.

  In the toner supply device of the present invention, the toner recovery pan is provided with a discharge port for discharging the liquid toner at the bottom and an inclined surface for flowing the stored liquid toner to the discharge port.

  Therefore, the toner in the toner collection pan is appropriately guided to the discharge port by the inclined surface, and can be properly discharged from this discharge port.

  According to the toner supply device of the present invention, the first gap between the peripheral surface of the toner supply roller and one side of the toner supply pan is set larger than the second clearance between the peripheral surface of the toner supply roller and the other side of the toner supply pan. Therefore, the liquid toner supplied from the toner supply unit to one side of the toner supply pan flows from the first gap side to the second gap side, and then flows along the axial direction of the toner supply roller. By increasing the contact area with the peripheral surface of the supply roller, cooling of the liquid toner is promoted, melting of the toner particles is suppressed, and a liquid toner layer having a uniform thickness is formed in the width direction of the toner supply roller. Can do.

FIG. 1 is a schematic diagram illustrating a printing unit equipped with a toner supply device according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the developing unit of this embodiment. FIG. 3 is a front view illustrating the toner supply device of this embodiment. FIG. 4 is a plan view illustrating the toner supply pan. FIG. 5 is a cross-sectional view illustrating the toner recovery pan. FIG. 6 is an exploded perspective view showing the toner supply device of this embodiment.

  Exemplary embodiments of a toner supply device according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example.

  FIG. 1 is a schematic diagram showing a printing unit equipped with a toner supply device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a developing unit of this embodiment, and FIG. 3 is a toner of this embodiment. FIG. 4 is a plan view showing the toner supply pan, FIG. 5 is a cross-sectional view showing the toner recovery pan, and FIG. 6 is an exploded perspective view showing the toner supply device of this embodiment.

  The electrophotographic printing apparatus according to the present embodiment is a liquid developing electrophotographic printer, and includes a paper feeding unit, a printing unit, and a paper discharging unit. For example, the paper feed unit can supply print sheets, which are sheets of sheets, one by one from the paper feed tray to the printing unit. The printing unit can perform printing on one side or both sides of the supplied printing sheet. The paper discharge unit can discharge a print sheet printed on one or both sides by the printing unit to a paper discharge tray.

  Hereinafter, the electrophotographic printing apparatus of this embodiment will be described in detail. As shown in FIG. 1, the printing unit 10 includes an intermediate transfer member 11, a backup roller 12, and a plurality (four in this embodiment) of developing units 13, 14, 15, and 16. Although not shown, the printing unit 10 further includes a print sheet conveying device, a toner fixing device, and the like. In this case, the printing unit 10 is configured to be able to perform process color printing, and is a developing unit corresponding to each process color of C (indigo), M (red), Y (yellow), and K (black). 13, 14, 15, and 16.

  The intermediate transfer member 11 is in contact with the backup roller 12, and a nip portion (transfer position) N1 is formed at the contact portion. A blanket 11a is wound around the peripheral surface of the intermediate transfer body 11, and the blanket 11a is made of urethane conductive rubber. The intermediate transfer body 11 has a bias voltage difference from a photosensitive drum 21 described later. I have it.

  On the other hand, the backup roller 12 is arranged to apply a pressure to the intermediate transfer body 11 at a predetermined pressure, for example, about 1 to 13 kg / cm, and forms the above-described nip portion N1. For this reason, the print sheet S is conveyed between the intermediate transfer member 11 and the backup roller 12 so that a predetermined nip pressure is applied. The backup roller 12 is applied with a transfer bias of about −800V, for example. Therefore, due to the difference between the bias voltage of the intermediate transfer body 11 and the backup roller 12, a force for sucking the liquid toner T from the intermediate transfer body 11 to the backup roller 12 side is given, and the liquid toner from the intermediate transfer body 12 to the printing sheet S is applied. T electrostatic transfer is promoted.

  The developing units 13, 14, 15, and 16 are arranged around the intermediate transfer body 11 along the rotation direction, and the configuration is the same except that the color of the liquid toner T to be used is different. ing. Therefore, in the following, the developing unit 13 will be described in detail.

  As shown in FIG. 2, the developing unit 13 forms an electrostatic latent image on the photosensitive drum 21 on the basis of image data transmitted from a control device (not shown), and liquid is formed at a position corresponding to the electrostatic latent image. The toner is supplied, and the image of the liquid toner T formed on the photosensitive drum 21 is transferred to the intermediate transfer body 11.

  Here, the liquid toner T is a toner in which particulate toner formed by a thermoplastic material and a pigment (pigment or dye) is dispersed and blended in a liquid carrier. Here, as a carrier, Liquid toner T is an oil-based solvent (for example, nonpolar, paraffinic solvent such as mineral oil) containing about 10 to 40 percent by weight of particulate toner having an average particle size of 1 to 2 μm. It is used as

  The developing unit 13 includes a photosensitive drum (photosensitive member) 21, a cleaning unit 22, a static eliminator 23, a charging device 24, an exposure device 25, and a developing device 26. The photosensitive drum 21 has a photosensitive layer formed on its peripheral surface including a photosensitive agent such as amorphous silicon (a-Si) or a photosensitive polymer. The photosensitive drum 21 is in contact with the intermediate transfer member 11 at the nip portion N2, and is configured to be able to transfer the liquid toner T on the photosensitive drum 21 to the intermediate transfer member 11 side.

  The photosensitive drum 21 has a cleaning unit 22, a static eliminator 23, a charging device 24, an exposure device 25, and a developing device from the upstream side along the rotation direction of the photosensitive drum 21 starting from the nip portion N2 around the photosensitive drum 21. 26 are arranged opposite to the photosensitive layer formed on the surface of the photosensitive drum 21 in order.

  The cleaning unit 22 includes a cleaning blade 22a, and can remove the liquid toner T remaining on the peripheral surface of the photosensitive drum 21 and discharge it to a toner collection path (not shown). In other words, the cleaning blade 22 a is a rectangular plate formed of an elastic material, and is supported so that the tip portion contacts the circumferential surface of the photosensitive drum 21. The liquid toner T on the circumferential surface of the photosensitive drum 21 is supported by the cleaning blade 22 a. Can be scraped off.

  The liquid toner T removed from the photosensitive drum 21 is discharged from a liquid toner discharge port 52d (not shown).

  The static eliminator 23 has a function of erasing charges remaining on the photosensitive layer of the photosensitive drum 21. The charging device 24 includes a plurality of non-contact discharge type chargers such as a corotron type or a scorotron type arranged along the circumferential direction of the photosensitive drum 21, and the photosensitive layer of the photosensitive drum 21 is uniformly formed. For example, it has a function of charging to about 500V.

  The exposure device 25 is composed of a light emitting device (LED array) in which light emitters (for example, LEDs) are arranged in a rod shape along the axial direction of the photosensitive drum 21, and is based on image data sent from a control device. Each LED is made to emit light. That is, the surface of the photosensitive layer of the photosensitive drum 21 that is uniformly charged by the charging device 24 is irradiated with light from the exposure device 25, so that the photosensitive layer is uncharged in the light irradiation portion, and the photosensitive layer. An electrostatic latent image based on the image data can be formed. The light emitting device may be configured to form an electrostatic latent image by scanning a semiconductor laser or the like based on image data instead of the LED array.

  The developing device 26 includes a toner storage unit 31, an anilox roller 32, a leveling roller 33, a developing roller 34, a toner charger 35, and toner recovery units 36 and 37. The liquid toner T can be transferred to the portion where the image is formed.

  The toner storage unit 31 stores the liquid toner T, and the liquid toner can be supplied and discharged so that a part of the anilox roller 32 is immersed in the liquid toner T. The anilox roller 32 is a metal roller, and a concave portion (cell) suitable for supplying the liquid toner T with a desired film thickness is formed on the entire surface of the anilox roller 32. The anilox roller 32 can be driven to rotate in the same direction as the photosensitive drum 21.

  The leveling roller 33 is made of urethane rubber, and is disposed between the anilox roller 32 and the developing roller 34, and the peripheral surface is in contact with the anilox roller 32 and the developing roller 34. Further, the leveling roller 33 is rotatable in such a direction that the peripheral surfaces thereof advance in the same direction at the contact point with the anilox roller 32.

  The developing roller 34 is made of conductive rubber and is disposed so as to form the nip portion N3 in contact with the photosensitive drum 21. Further, the developing roller 34 is rotatable at a nip portion N3 such that the circumferential surface of the photosensitive drum 31 and the circumferential surface of the developing roller 34 advance in the same direction. Further, the developing roller 34 is set so that its peripheral surface speed is the same as the peripheral surface speed of the photosensitive drum 21. The toner charger 35 has a function of uniformly charging the peripheral surface of the developing roller 34.

  As described above, the conductive developing roller 34 and the photosensitive drum 21 come into contact with each other at the nip portion N3, so that the toner charged from the peripheral surface of the developing roller 34 to the portion where the electrostatic latent image is formed on the photosensitive drum 21 is included. The liquid toner T is transferred and developed.

  Then, the developed liquid toner T on the peripheral surface of the photosensitive drum 21 is transferred to the intermediate transfer body 11 at the nip portion N2, and a liquid toner layer containing an image of the toner is formed on the peripheral surface of the intermediate transfer body 11. Can be formed.

  The toner collecting unit 36 can remove and collect the liquid toner T remaining on the peripheral surface of the developing roller 34. The toner collecting unit 37 can remove and collect the liquid toner T remaining on the peripheral surface of the leveling roller 33. The toner collecting units 36 and 37 have substantially the same configuration, and the residual toner peeled off from the leveling roller 33 and the developing roller 34 as a toner supply roller is conveyed to a predetermined position and collected in a toner tank (not shown). To do.

  Meanwhile, in the developing device 26, the liquid toner T is supplied from the toner storage unit 31 to the developing roller 34 by the anilox roller 32 and the leveling roller 33. The liquid toner remaining on the peripheral surface of the developing roller 34 is It is scraped off by the toner recovery units 36 and 37, recovered, and reused. In this case, the rollers 32, 33, and 34 are in contact with each other and supply the liquid toner T to generate heat, and the temperature of the liquid toner T rises. When the temperature of the liquid toner T rises, the contained toner particles are easily melted, and it becomes difficult to form a liquid toner layer having a uniform film thickness in the width direction of the anilox roller 32, and the print quality is deteriorated.

  Therefore, in the liquid toner supply device of the present embodiment configured by the toner storage unit 31, the anilox roller 32, the leveling roller 33 and the like in the developing device 26, the liquid toner T is circulated to increase the contact area with the anilox roller 32. The liquid toner T is cooled by enlarging and performing heat exchange here.

  As shown in FIGS. 3 to 6, the liquid toner supply device of this embodiment includes an anilox roller (toner supply roller) 32, a toner supply pan 41, a toner supply line 42, a toner blade 43, and a toner recovery pan. 44.

  As described above, the anilox roller 32 is a metal roller in which concave portions (cells) suitable for supplying the liquid toner T with a desired film thickness are formed on the entire surface of the anilox roller 32 in a predetermined direction ( In FIG. 3, it can be rotated in the clockwise direction.

  The toner supply pan 41 stores the liquid toner T and is long along the axial direction of the anilox roller 32 and is bent (or curved) along the circumferential surface of the anilox roller 32. The side wall portions 52 and 53 rising from the end portion of the anilox roller 32 in the bottom wall portion 51 in the axial direction, and the side wall portions 52 and 53 rising from one end portion of the bottom wall portion 51 in the circumferential direction of the anilox roller 32. It is comprised from the back wall part 55 which continues in a row. In this case, the bottom wall portion 51 is formed with a bent portion 56 at a substantially intermediate position in the circumferential direction of the anilox roller 32, and is first on one side (right side in FIG. 3) with respect to the bent portion 56. An inclined portion 51a is formed, and a second inclined portion 51b is formed on the other side (left side in FIG. 3) with respect to the bent portion 56, that is, on the rear wall portion 55 side. In the toner supply pan 41, the bent portion 56 is at the lowest position in the vertical direction. Here, a plurality (two in this embodiment) of toner discharge ports 57 are arranged at predetermined intervals in the axial direction of the anilox roller 32. Is formed.

  The base of the toner supply line 42 is connected to a toner storage tank (not shown) via a supply pump. The toner supply line 42 is a first branch line 42a that is branched into two at the tip end side, and the first branch line 42a is a second branch line 42b that is branched into two at the tip end side. Yes. On the other hand, the toner supply pan 41 has a plurality of (four in this embodiment) toner supply ports (toner supply portions) 58 at predetermined intervals in the axial direction of the anilox roller 32 on the first inclined portion 51a in the bottom wall portion 51. Is formed. In the toner supply line 42, the tips of the four second branch lines 42 b are connected to the toner supply ports 58 in the toner supply pan 41 from below. Therefore, the toner supply line 42 can supply the liquid toner T to the toner supply pan 41 through each toner supply port 58 from each second branch line 42b.

  In this case, the toner supply pan 41 fully stores the liquid toner T, and the anilox roller 32 is a part of the liquid toner T stored in the toner supply pan 41. About 1/3 is immersed, and the liquid toner T can be supplied to the leveling roller 33 by rotating in this immersion state.

  The toner blade 43 scrapes off excess liquid toner T from the anilox roller 32. The toner blade 43 is a plate material having a long rectangular shape along the axial direction of the anilox roller 32, and a base end portion is fixed to a rear wall portion 55 of the toner supply pan 41 by a plurality of bolts 59. The tip of the toner blade 43 extends toward the anilox roller 32, and the tip is in contact with the peripheral surface of the anilox roller 32. In this case, the tip of the toner blade 43 is in contact with the peripheral surface of the anilox roller 32 after being immersed in the liquid toner T of the toner supply pan 41, so that it is extra to supply the leveling roller 33 from the anilox roller 32. The liquid toner T can be scraped off.

  The toner collection pan 44 is disposed below the toner supply pan 41, and receives the liquid toner T overflowing over one side of the toner supply pan 41, that is, the front wall portion 54. The liquid toner T discharged from the discharge port 57 is received. Similar to the toner supply pan 41, the toner collection pan 44 is long along the axial direction of the anilox roller 32 and is bent (or curved) in the vertical direction with respect to the axial direction of the anilox roller 32; The side wall portions 62 and 63 rising from the axial end portion of the anilox roller 32 in the bottom wall portion 61 and the side wall portions 62 and 63 rising from the end portions in the circumferential direction of the anilox roller 32 in the bottom wall portion 61. It is composed of a continuous front wall portion 64 and a rear wall portion 65.

  In this case, the bottom wall portion 61 is bent at a substantially intermediate position in the axial direction of the anilox roller 32, and inclined portions (inclined surfaces) 61a are formed on both sides with this position as a fulcrum. The inclined portion 61a is preferably inclined by 5 to 10 degrees with respect to the horizontal. The toner collection pan 44 has the lowest bent position in the vertical direction, and a toner discharge port 67 is formed there. Accordingly, the toner collection pan 44 is provided with the inclined portion 61a toward the discharge port 67 on the bottom wall portion 61 and is set within a predetermined angle range, whereby the dischargeability of the liquid toner T can be improved and the apparatus Increase in size can be suppressed.

  The toner collection pan 44 has a shape that is slightly larger than the toner supply pan 41 positioned above, and has a capacity capable of accommodating the toner supply pan 41. Therefore, the liquid toner T overflowed from the toner supply pan 41 can be received, and the liquid toner T discharged from each discharge port 57 of the toner supply pan 41 can be received. The toner recovery pan 44 can collect the liquid toner T received from the toner supply pan 41 at the central portion along the inclined portions 61 a of the bottom wall portion 61 and discharge the liquid toner T from the discharge port 67.

  In the liquid toner supply apparatus of the present embodiment configured as described above, a gap is provided between the peripheral surface of the anilox roller 32 and the inner wall surface of the toner supply pan 41, as shown in FIG. By storing the liquid toner T in this gap, when the anilox roller 32 rotates, the liquid toner T can be carried in the recesses (cells) on the peripheral surface. In this case, the gap between the peripheral surface of the anilox roller 32 and the inner wall surface of the toner supply pan 41 opens on one side in the circumferential direction of the nylox roller 32, but is almost blocked by the toner blade 43 on the other side. It is in the state.

  In the present embodiment, the first clearance S1 between the circumferential surface of the anilox roller 32 and one side in the circumferential direction of the anilox roller 32, that is, the inner wall surface 51c on the first inclined portion 51a side, is the circumferential surface of the anilox roller 32. The anilox roller 32 is set to be larger than the second gap S2 with the inner wall surface 51d on the other side in the circumferential direction, that is, on the second inclined portion 51b side.

  In this case, the first gap S1 is a gap formed between the circumferential surface of the anilox roller 32 and the inner wall surface 51c of the toner supply pan 41, and the circumference of the anilox roller 32 from the bent portion 56 (discharge port 57). It is the minimum gap formed on one side in the direction. The second gap S2 is a gap formed between the peripheral surface of the anilox roller 32 and the inner wall surface 51d of the toner supply pan 41, and the circumferential direction of the anilox roller 32 from the bent portion 56 (discharge port 57). Is the minimum gap formed on the other side. Here, the first gap S1> the second gap S2.

  The toner supply port 58 provided in the toner supply pan 41 is one side (right side in FIG. 3) from the first gap S1 in the circumferential direction of the anilox roller 32, that is, the toner supply pan 41. To the side where the liquid toner T overflows.

  Further, in the gap provided between the peripheral surface of the anilox roller 32 and the inner wall surface of the toner supply pan 41, the peripheral surface of the anilox roller 32 and the central portion in the circumferential direction of the anilox roller 32, that is, the bent portion 57. A third gap S3 is set between the inner wall surface 51e and the inner wall surface 51e. The third gap S3 is located between the first gap S1 and the second gap S2 in the circumferential direction of the anilox roller 32, and is set larger than the first gap S1 and the second gap S2.

  In this case, the third gap S3 is a gap formed between the circumferential surface of the anilox roller 32 and the inner wall surface 51e of the toner supply pan 41, and the first gap S1 and the second gap in the circumferential direction of the anilox roller 32. This is the maximum gap formed between the gaps S2. Here, the third gap S3> the first gap S1> the second gap S2.

  Accordingly, the liquid toner T supplied from the toner supply port 58 into the toner supply pan 41 is a gap between the peripheral surface of the anilox roller 32 and the inner wall surface of the toner supply pan 41 as indicated by an arrow A in FIG. As the anilox roller 32 rotates, it flows along the circumferential surface of the anilox roller 32 toward the first gap S1, and further flows through the third gap S3 toward the second gap S2. However, since the second gap S2 is narrower than the first gap S1 and the third gap S3, the liquid toner T hardly flows from the second gap S2 to the rear wall 55 side, and from here, in the axial direction of the anilox roller 32 Flowing. That is, as the anilox roller 32 rotates, the liquid toner T that flows from the first gap S1 side through the third gap S3 to the second gap S2 side passes through the second gap S2 in the axial direction of the anilox roller 32. Change the flow on both sides.

  The flow of the liquid toner T is based on the fact that the gap on the rear wall 55 side of the toner supply pan 41 is closed by the toner blade 43, and the liquid toner T returns from the anilox roller 32 to the gap by the toner blade 43. It is thought that this is also caused by this.

  Since the toner supply pan 41 has a plurality of toner supply ports 58, the liquid toner T flowing in the axial direction of the anilox roller 32 from the second gap S 2 in the toner supply pan 41 is another toner supply port 58. Collision with the flow of the liquid toner T that has flown from and flows toward the third gap S3. Then, the liquid toner T flows from the third gap S3 toward the first gap S1 and merges with the liquid toner T newly supplied from the toner supply port 58, or overflows from the opening side of the toner supply pan 41. To do.

  The liquid toner T supplied to the toner supply pan 41 circulates in the gap between the anilox roller 32 and the toner supply pan 41, and the contact area between the liquid toner T and the anilox roller 32 is increased, so that the heat exchange efficiency is increased. Thus, the liquid toner T whose temperature has been increased is efficiently cooled by the anilox roller 32.

  In the printing unit 10 of the electrophotographic printing apparatus of the present embodiment configured as described above, when the printing sheet S is fed to the printing unit 10 as shown in FIGS. The developing units 13 to 16 have corresponding C (blue), M (red), and Y (yellow) on the peripheral surface of the photosensitive drum 21 on which the electrostatic image to be transferred to the printing surface of the printing sheet S is formed. ), K (black) liquid toner T of each color is transferred, and an image is developed on the photosensitive drum 21. Then, the liquid toner T of each color transferred to the peripheral surface of the photosensitive drum 21 is transferred to the same position on the intermediate transfer body 11, and the print sheet S passes through the nip portion N 1 between the intermediate transfer body 11 and the backup roller 12. At this time, the liquid toner T is transferred from the peripheral surface of the intermediate transfer body 11 to the printing surface in contact with the intermediate transfer body 11 in the print sheet S.

  Then, the printing sheet S on which the liquid toner T is transferred to the printing surface is conveyed, and is fixed by heating and pressurizing the liquid toner T by the fixing device, and printing is completed.

  At this time, in the developing device 26 in the developing units 13 to 16, the anilox roller 32 rotates, so that the liquid toner T stored in the toner storage unit 31 is scraped up, and the liquid toner T enters the concave portion on the peripheral surface. A predetermined amount of liquid toner T is transferred to the leveling roller 33. On the other hand, the peripheral surface of the developing roller 34 is uniformly charged by the toner charger 35, and the liquid toner T of the leveling roller 33 is transferred to the developing roller 34. The developing roller 34 is in contact with the photosensitive drum 21 at the nip portion N3, whereby the charged liquid toner T is transferred from the peripheral surface of the developing roller 34 to the portion where the electrostatic latent image of the photosensitive drum 21 is formed, Further, the liquid toner T on the peripheral surface of the photosensitive drum 21 is transferred to the intermediate transfer body 11 at the nip portion N2.

  On the other hand, the developing roller 34 supplies the liquid toner T to the photosensitive drum 21, but a part of the liquid toner T remains on the peripheral surface. The leveling roller 33 also transfers the liquid toner T to the developing roller 34, but a part of the liquid toner T remains on the peripheral surface. Therefore, the toner collection units 36 and 37 remove and collect the liquid toner T remaining on the peripheral surfaces of the leveling roller 33 and the developing roller 34.

  In the developing device 26, when the liquid toner T is supplied to the anilox roller 32, the leveling roller 33, and the developing roller 34, the rotational directions of the leveling roller 33 and the developing roller 34 are different. The temperature of the liquid toner T rises due to frictional heat between the 34. However, in this embodiment, the liquid toner T is supplied from the toner supply port 58 to the toner supply pan 41 and flows along the peripheral surface as the anilox roller 32 rotates, and the first gap S1 to the third gap S3. Flows through the second gap S2 and passes through the second gap S2 in the axial direction of the anilox roller 32 and circulates. Therefore, the liquid toner T circulating in the toner supply pan 41 comes into contact with the anilox roller 32 and is cooled, and the temperature rise is suppressed.

  Thus, in the toner supply device of this embodiment, the toner supply pan 41 for storing the liquid toner T and immersing the anilox roller 32 in the liquid toner T is provided, and the anilox roller 32 in the toner supply pan 41 is provided. The toner supply port 58 is provided on one side in the circumferential direction, the toner blade 43 is provided on the other side, and the bottom wall portion 51 of the toner supply pan 41 is bent or curved along the circumferential surface of the anilox roller 32. The first gap S1 between the circumferential surface of the anilox roller 32 and the inner wall surface 51c on one side is set larger than the second gap S2 between the circumferential surface of the anilox roller 32 and the inner wall surface 51d on the other side.

  Accordingly, the liquid toner T supplied from the toner supply port 58 to one side of the toner supply pan 41 flows from the first gap S1 side to the second gap S2 side along the circumferential direction of the anilox roller 32. Since the two gaps S <b> 2 are narrow, it flows from here along the axial direction of the anilox roller 32. Therefore, in the toner supply pan 41, the liquid toner T circulates in the circumferential direction and the axial direction along the circumferential surface of the anilox roller 32, and the liquid toner T and the circumferential surface of the anilox roller 32 are in contact with each other. By expanding the area, cooling of the liquid toner T is promoted, melting of the toner particles is suppressed, and a liquid toner layer having a uniform film thickness can be formed in the width direction of the anilox roller 32.

  In the toner supply device of this embodiment, a third gap S3 between the peripheral surface of the anilox roller 32 and the inner wall surface 51e is provided between the first gap S1 and the second gap S2 in the circumferential direction of the anilox roller 32. The third gap S3 is set larger than the first gap S1 and the second gap S2. Accordingly, the liquid toner T supplied from the toner supply port 58 to one side of the toner supply pan 41 has a third gap S3 wider than the first gap S1 along the circumferential direction of the anilox roller 32 from the first gap S1 side. Since the third gap S3 is wide, the liquid toner T easily flows from the first gap S1 side to the second gap S2 side, and the cooling efficiency of the liquid toner T is improved. can do.

  In the toner supply device of this embodiment, the toner supply port 58 is provided on one side of the first gap S1, that is, on the opening side where the liquid toner T can overflow. Accordingly, the liquid toner T supplied from the toner supply port 58 to one side of the toner supply pan 41 flows from the wide first gap S1 side to the narrow second gap S2 side and from there flows in the axial direction of the anilox roller 32. Thus, the circulation efficiency of the liquid toner T can be improved.

  In the toner supply device of this embodiment, a plurality of toner supply ports 58 are provided at equal intervals in the axial direction of the anilox roller 32. Accordingly, the liquid toner T supplied from the toner supply port 58 to one side of the toner supply pan 41 flows almost uniformly in the axial direction of the anilox roller 32, and the liquid having a uniform film thickness in the width direction of the anilox roller 32. A toner layer can be formed. In this case, the toner supply line 42 first branches into two first branch lines 42a, and further branches into two to form four second branch lines 42b, which are connected to the respective toner supply ports 58. The flow rate of the liquid toner T supplied from the toner supply line 42 to each toner supply port 58 can be made substantially the same, and the supply of the liquid toner T in the width direction of the anilox roller 32 can be stabilized. Can do.

  In the toner supply device of this embodiment, the toner collection pan 44 is disposed below the toner supply pan 41, and the liquid toner T overflowing from one side of the toner supply pan 41 can be received by the toner collection pan 44. Therefore, by overflowing the liquid toner T in the toner supply pan 41 from one side, the circulation performance of the liquid toner T in the toner supply pan 41 can be improved, and the circulation efficiency of the liquid toner T can be improved.

  In the toner supply device of this embodiment, a discharge port 57 for discharging the liquid toner T to the toner recovery pan 44 is provided at the bottom of the toner supply pan 41. After the printing is finished and the apparatus is stopped, that is, when the supply of the liquid toner T becomes unnecessary, the liquid toner T in the toner supply pan 41 can be discharged from the discharge port 57 to the toner recovery pan 44, The quality deterioration of the liquid toner T due to toner particle precipitation can be suppressed.

  In the above-described embodiment, the toner supply pan 41 has a substantially V-shaped cross section by providing the bent portion 56 on the bottom wall portion 51. However, the present invention is not limited to this shape. For example, the bottom wall of the toner supply pan may have a substantially U-shaped cross-sectional shape by forming a curved shape with one arc or a plurality of arcs. Further, the toner supply pan is not limited to the substantially V-shaped cross-section or the substantially U-shaped cross-section, and the toner supply pan may have any shape as long as the size relationship between the first gap S1 and the second gap S2 is achieved. Good.

  In the above-described embodiment, the toner supply port 58 is provided on one side of the first gap S1, but the toner supply port 58 is on the other side of the first gap S1, that is, the first gap S1 and the third gap S3. You may provide between.

  In the embodiment described above, the toner supply roller is an anilox roller, and the liquid toner is supplied to the photosensitive drum 21 by the anilox roller, the leveling roller 33, and the developing roller 34. However, the present invention is limited to this configuration. Instead of the above, only the anilox roller and the developing roller 34 may be used, and further rollers may be added. The intermediate transfer body 11 is a drum type, but may be a belt type. In this case, the surface of the belt type substrate may be made of the same material as the blanket.

  The toner supply device according to the present invention sets the gap between the peripheral surface of the toner supply roller and the toner supply pan to a predetermined amount, thereby improving the liquid toner flow in the toner supply pan and improving the cooling efficiency of the liquid toner. The liquid toner layer having a uniform film thickness can be formed in the width direction of the supply roller, and can be applied to any type of electrophotographic printing apparatus.

DESCRIPTION OF SYMBOLS 10 Printing part 11 Intermediate transfer body 12 Backup roller 13, 14, 15, 16 Developing unit 21 Photosensitive drum 22 Cleaning unit 23 Charger 24 Charger 25 Exposure apparatus 26 Developing apparatus 31 Toner storage part 32 Anilox roller (toner supply roller)
33 Leveling roller 34 Developing roller 35 Toner charger 36, 37 Toner recovery unit 41 Toner supply pan 42 Toner supply line 43 Toner blade 44 Toner recovery pan 57, 67 Discharge port 58 Toner supply port (toner supply unit)
S1 1st gap S2 2nd gap S3 3rd gap

Claims (7)

A toner supply pan for storing liquid toner;
A toner supply unit for supplying liquid toner to the toner supply pan;
A toner supply roller capable of supplying liquid toner by rotating partly immersed in the liquid toner stored in the toner supply pan; and
A toner blade that scrapes off excess liquid toner from the toner supply roller;
A toner supply device comprising:
The toner supply pan is provided with the toner supply portion on one side in the circumferential direction of the toner supply roller and the blade on the other side, and is bent or bent along the circumferential surface of the toner supply roller. A curved inner wall is provided,
A first gap between the peripheral surface of the toner supply roller and the inner wall surface on the one side is set larger than a second gap between the peripheral surface of the toner supply roller and the inner wall surface on the other side;
A toner supply device.   A third gap between the circumferential surface of the toner supply roller and the inner wall surface is provided between the first gap and the second gap in the circumferential direction of the toner supply roller. The toner supply device according to claim 1, wherein the toner supply device is set to be larger than one gap and the second gap.   The toner supply apparatus according to claim 1, wherein the toner supply unit is provided on the one side with respect to the first gap.   4. The toner supply device according to claim 1, wherein a plurality of the toner supply units are provided at equal intervals in the axial direction of the toner supply roller. 5.   5. The toner supply device according to claim 1, further comprising a toner collection pan that receives liquid toner overflowed from the one side of the toner supply pan, below the toner supply pan. 6. .   6. The toner supply device according to claim 5, wherein the toner supply pan is provided with a discharge port at the bottom for discharging liquid toner to the toner recovery pan.   7. The toner supply according to claim 5, wherein the toner collection pan is provided with a discharge port for discharging the liquid toner at a bottom portion and an inclined surface for flowing the stored liquid toner to the discharge port. apparatus.

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