JP4554909B2 - Wet electrophotographic printer - Google Patents

Description

  The present invention relates to a wet electrophotographic printing apparatus in which a toner image developed on a photosensitive drum with liquid toner is transferred onto a sheet.

  Since the toner image developed and formed on the photosensitive drum contains a solvent, it is necessary to remove this excess solvent before transferring the toner image onto a sheet.

  In the prior art as a means for removing the solvent, the surface of the photosensitive drum after the development process and after the toner image is set by the set charger is inclined from the surface or true. There is known one in which air is blown in the angular direction and the liquid developer liquid surface on the surface of the photosensitive drum is disturbed by the blowing air to evaporate the solvent in the liquid developer (for example, Patent Document 1). ).

JP 2001-83806 A

  In the above conventional technique, the liquid developer liquid surface is disturbed by blowing air to evaporate the solvent in the liquid developer. Therefore, before the air is blown, an image is set with a set charger. However, the image disturbance due to the disturbance on the developer liquid surface could not be completely removed.

In the above conventional technique, since the solvent is scattered by the air blown to the surface of the photosensitive drum, it is necessary to provide a receiving tray and an enclosure for receiving the blown solvent on the downstream side of the air blowing. Since the solvent scattered from the surface is scattered as a turbulent flow by the blowing air, it is difficult to completely cover the splash at this time.

The present invention solves the above-described conventional problems and provides a wet electrophotographic printing apparatus that can dry a toner image formed by a liquid toner developed on a photosensitive drum without being disturbed and can be dried without scattering of a solvent. In this apparatus, a charger, an exposure device, a developing device, and a dryer are arranged around the photosensitive drum from the upstream side in the rotation direction of the photosensitive drum, and the photosensitive drum is used by the charger and the exposure device. In the wet type electronic printing apparatus in which the electrostatic latent image formed on the peripheral surface of the toner is developed with a developer using a developer, and the liquid toner image is dried with a dryer and then transferred to a sheet. the dryer in the downstream side in the rotating direction of the photosensitive drum, and a discharge chamber facing the discharge opening over its axial length with respect to the photosensitive drum, in the rotating direction upstream side of the photosensitive drum, the photosensitive drum A suction chamber that faces the suction port over its axial length, a suction chamber and these discharge chamber was communicated along the layered on the peripheral surface of the photosensitive drum is provided with a passage through which air flows in the rotational direction opposite to the direction of the photosensitive drum together, sealed with the side seal facing both sides of this passage, at a position adjacent to the upstream side in the rotation direction of the photosensitive drum of the suction chamber of the dryer, is free on the surface of the photosensitive drum after the development by the developing unit A suction device for sucking the solvent is arranged.

  According to the present invention, the toner image developed with the liquid toner on the peripheral surface of the photosensitive drum by the developing device is sucked by the suction device, so that most of the solvent contained in the toner image is converted into the toner image. It is possible to separate and remove without disturbing and without scattering around.

  Further, since most of the solvent contained in the toner image can be removed on the upstream side of the dryer, the burden on the dryer can be reduced. The air in the dryer can be efficiently dried without disturbing the toner image by flowing along the peripheral surface of the photosensitive drum.

  In particular, the discharge port to the passage of the air flowing through the passage in the dryer is disposed downstream of the photosensitive drum in the rotation direction so that the air flows in the direction opposite to the rotation direction of the photosensitive drum. The momentum of the air flowing through this passage is strong on the downstream side of the dryer, weak on the upstream side, and the influence of the air flow on the still unstable toner image that has just entered the upstream side of the dryer can be reduced. It is possible to prevent the toner image from being disturbed by the air flow in this portion.

  FIG. 1 schematically shows an overall configuration of an example of a wet electrophotographic printing apparatus to which the present invention is applied. In FIG. 1, 1 is a paper feeding unit, 2 is a printing unit, and 3 is a winding unit. The paper 4 supplied from the roll supported by the paper feed unit 1 is printed on both sides by the printing unit 2 on each side, and is wound again in a roll shape by the winding unit 3.

  In the printing unit 2, two electrophotographic printers 5 a, 5 b and 5 c, 5 d are arranged on both sides of the path of the paper 4 in the traveling direction of the paper 4. Each of the electrophotographic printers 5a to 5d has a symmetrical configuration on the front side and the back side of the paper 4, but basically has the same configuration. Therefore, one of the electrophotographic printers 5a is the same. This will be described with reference to FIG.

  In FIG. 2, reference numeral 6 denotes a transfer roller that is in contact with the paper 4 and rotates in the traveling direction of the paper 4, and 7 is a toner that is transferred to the transfer roller 6 and rotates in the same circumferential direction. This is a photosensitive drum that transfers an image to a transfer roller 6. The photosensitive drum 7 has a structure in which an organic or amorphous silicon photosensitive layer is provided on a conductive substrate, and an electrostatic latent image is formed on the surface of the photosensitive drum 7 by applying light to the photosensitive layer. It has become. Around the photosensitive drum 7, a charger 8 for uniformly applying an electrostatic potential to the photosensitive drum 7 from the upstream side in the rotation direction, an exposure device 9 for forming a latent image on the surface of the photosensitive drum 7, and the exposure device 9 The first and second image forming portions 11a and 11b including a developing device 10 for developing the toner are disposed. In both the image forming portions 11a and 11b, for example, yellow, magenta (or cyan, black), etc. These two color images are formed.

  Further, on the downstream side of the second image forming unit 11b on the downstream side, a set charger 12 for setting the toner images developed by the image forming units 11a and 11b on the photosensitive drum 7, a suction device 13, and an image The dryer 14 which dries is arranged. The set charger 12 forms an electric field for causing the toner particles in the liquid developer to be electrophoresed toward the photosensitive drum 7, and an ion generator or the like is used.

The suction device 13 provided on the downstream side of the set charger 12 includes a suction nozzle 13a facing the entire length of the photosensitive drum 7 in the axial direction, and a suction pipe 13b connecting the suction nozzle 13a to the suction port of the blower. As shown in FIG. 2, the suction device 13 is provided on the upstream side in the rotational direction of the photosensitive drum 7 of the dryer 14 to be described later and adjacent to the suction chamber in which air flowing through the dryer is sucked. It has been.

  The dryer 14 has a discharge chamber 14a facing the discharge port over the entire length in the axial direction on the downstream side in the rotation direction of the photosensitive drum 7, and a suction port over the entire length in the axial direction on the upstream side in the rotation direction of the photosensitive drum 7. The opposing suction chamber 14b and a passage 14c that communicates the chambers 14a and 14b with the peripheral surface of the photosensitive drum 7 along a layered shape. The discharge chamber 14a is connected to a blower outlet through an air supply pipe 14d, and a suction pipe (not shown) is connected to the suction chamber 14b. The air supplied to the discharge chamber 14a is heated to a predetermined temperature as necessary.

  Both sides of the discharge chamber 14a, the suction chamber 14b, and the passage 14c are sealed by side seals 15 and 15 facing both side surfaces of the photosensitive drum 7.

  In the above configuration, a toner image is formed on the surface of the photosensitive drum 7 by the image forming portions 11a and 11b as the photosensitive drum 7 rotates. The toner image is set on the photosensitive drum 7 side by the set charger 12. Next, the toner image is sucked by the suction device 13.

  The surface of the photosensitive drum 7 facing the suction device 13 is as shown in FIG. 3, and the toner layer a that becomes a toner image by the set charger 12 is set on the photosensitive drum 7 side. On the outside, 60 to 80% of the solvent layer b is released over a thickness of 3 to 4 μm. Therefore, at this position, the solvent layer b is sucked by the suction device 13 and most of the solvent component of the toner image is removed.

  Then, while the toner image passes through the dryer 14, the solvent remaining on the toner image is evaporated and dried. At this time, in the dryer 14, air from the discharge chamber 14a located downstream in the rotation direction of the photosensitive drum 7 flows in a layered manner toward the upstream side in the rotation direction through the passage 14c, and the solvent is evaporated in this air flow. The toner image is dried. Since the air passing through the dryer 14 flows in the direction opposite to the rotation direction of the photosensitive drum 7, the momentum of the air flowing through the passage 14c of the dryer 14 is strong on the downstream side in the rotation direction of the photosensitive drum 7 and weak on the upstream side. Become. Therefore, immediately after entering the dryer 14, the influence of the air flow on the still unstable toner image can be reduced, and the disturbance of the toner image due to the air flow in this portion can be reduced.

  Further, the contact speed of air with the surface of the photosensitive drum 7 in the dryer 14 is relatively increased by the rotational peripheral speed of the photosensitive drum 7, and a drying effect can be expected accordingly.

  In the above-described embodiment, an example in which the set charger 12 is arranged on the upstream side of the suction device 13 is shown, but this is not necessarily required.

1 is a schematic configuration explanatory diagram illustrating an example of a wet electrophotographic printing apparatus. It is a rough structure explanatory view showing an example of the important section of the present invention. It is action explanatory drawing in a suction device part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Paper feed part, 2 ... Printing part, 3 ... Winding part, 4 ... Paper, 5a, 5b, 5c, 5d ... Electrophotographic printing machine, 6 ... Transfer roller, 7 ... Photosensitive drum, 8 ... Charger, 9 DESCRIPTION OF SYMBOLS ... Exposure device, 10 ... Developer, 11a, 11b ... Image forming part, 12 ... Set charger, 13 ... Suction device, 13a ... Suction nozzle, 13b ... Suction tube, 14 ... Dryer, 14a ... Discharge chamber, 14b ... Suction chamber, 14c ... passage, 14d ... air supply pipe, 15 ... side seal.

Claims (1)

Around the photosensitive drum, a charger, an exposure device, a developing device, and a dryer are arranged from the upstream side in the rotation direction of the photosensitive drum, and an electrostatic latent image formed on the peripheral surface of the photosensitive drum by the charger and the exposure device. In a wet electronic printing apparatus that uses a liquid toner to develop in a developing device, and the liquid toner image is dried by a dryer and then transferred to paper.
In the dryer, on the downstream side in the rotation direction of the photosensitive drum, a discharge chamber facing the discharge port over the entire length in the axial direction with respect to the photosensitive drum, and in the axial direction with respect to the photosensitive drum in the upstream direction of rotation of the photosensitive drum A suction chamber facing the suction port over the entire length, and a passage through which air flows in the direction opposite to the rotation direction of the photosensitive drum, in which the discharge chamber and the suction chamber communicate with each other along the circumferential surface of the photosensitive drum, Seal both sides of the passage with opposing side seals,
Wet wherein a position adjacent to the upstream side in the rotation direction of the dryer photosensitive drum suction chamber, characterized in that a suction device is provided for sucking the solvent is free on the surface of the photosensitive drum after the development by the developing unit Electronic printing device.

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