Roller type liquid developing apparatus

Claim 2

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head for applying the developing solution stored in said developing tank to a sheet-like recording medium so as to develop an electrostatic latent image formed on the sheet-like recording medium; and a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head by a negative pressure effect, and subsequently circulating the developing solution into said developing solution tank, wherein said developing head comprises a rod-like base, a developing slit comprising an elongated opening formed in a surface of said rod-like base which corresponds to the sheet-like recording medium and said developing slit having a length smaller than a width of the sheet-like recording medium, a hollow portion, formed to be continuous with said developing slit, for receiving the developing solution from said developing solution tank, and a developing roller which is arranged in said hollow portion so as to be rotated while an outer surface of said developing roller opposes an opening end of said developing slit; said developing roller capable of carrying the developing solution on the outer surface thereof; a liquid suction slit having a bottom portion formed in an upper surface of said rod-like base to be adjacent to said developing slit; a communicating hole, having a small cross-sectional area, for causing said bottom portion of said liquid suction slit to communicate with a negative pressure from said pump; and a separating slit formed between said developing slit and said liquid suction slit so as to be partly kept open to the air.

Claim 3

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head for applying the developing solution stored in said developing tank to a sheet-like recording medium so as to develop an electrostatic latent image formed on the sheet-like recording medium; and a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head by a negative pressure effect, and subsequently circulating the developing solution into said developing solution tank, wherein said developing head comprises a rod-like base, a developing slit comprising an elongated opening formed in a surface of said rod-like base which corresponds to the sheet-like recording medium and said developing slit having a length smaller than a width of the sheet-like recording medium, a hollow portion, formed to be continuous with said developing slit, for receiving the developing solution from said developing solution tank, and a developing roller which is arranged in said hollow portion so as to be rotated while an outer surface of said developing roller opposes an opening end of said developing slit said developing roller capable of carrying the developing solution on the outer surface thereof; said developing roller including a magnetic material; a blade which is formed by magnetizing a strip-like magnetic sheet obtained by dispersing magnetic particles in an elastic member so as to be attracted and held on said outer surface of said developing roller by a magnetic attracting force; and a blade stopper for positioning said blade, arranged between a position of a downstream end portion of a developing portion in said developing slit in he direction of rotation of said developing roller and a position where said outer surface of said developing roller rotates out of said developing solution and moves toward an upstream end portion of said developing portion.

Claim 4

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head for applying the developing solution stored in said developing tank to a sheet-like recording medium so as to develop an electrostatic latent image formed on the sheet-like recording medium; and a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head by a negative pressure effect, and subsequently circulating the developing solution into said developing solution tank, wherein said developing head comprises a rod-like base, a developing slit comprising an elongated opening formed in a surface of said rod-like base which corresponds to the sheet-like recording medium and said developing slit having a length smaller than a width of the sheet-like recording medium, a hollow portion, formed to be continuous with said developing slit, for receiving the developing solution from said developing solution tank, and a developing roller which is arranged in said hollow portion so as to be rotated while an outer surface of said developing roller opposes an opening end of said developing slit said developing roller capable of carrying the developing solution on the outer surface thereof; said developing roller including a magnetic material; a blade which is formed by magnetizing a strip-like magnetic sheet obtained by dispersing magnetic particles in an elastic member so as to be attracted and held on said outer surface of said developing roller by a magnetic attracting force; and a blade stopper for positioning said blade, arranged between a position of a downstream end portion of a developing portion in said developing slit in he direction of rotation of said developing roller and a position where said outer surface of said developing roller rotates out of said developing solution and moves toward an upstream end portion of said developing portion.

Claim 5

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head for applying the developing solution stored in said developing tank to a sheet-like recording medium so as to develop an electrostatic latent image formed on the sheet-like recording medium; and a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head by a negative pressure effect, and subsequently circulating the developing solution into said developing solution tank, wherein said developing head comprises a rod-like base, a developing slit comprising an elongated opening formed in a surface of said rod-like base which corresponds to the sheet-like recording medium and said developing slit having a length smaller than a width of the sheet-like recording medium, a hollow portion, formed to be continuous with said developing slit, for receiving the developing solution from said developing solution tank, and a developing roller which is arranged in said hollow portion so as to be rotated while an outer surface of said developing roller opposes an opening end of said developing slit said developing roller capable of carrying the developing solution on the outer surface thereof; a developing roller including a magnetic material; a roller position regulating member arranged to allow a regulating surface thereof to come into contact with said outer surface of said developing roller at a predetermined position; and means for positioning said developing roller so as to allow said developing roller to be slidably rotated on the regulating surface such that said outer surface of said developing roller is magnetically attracted to the regulating surface of said roller position regulating member.

Claim 6

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head for applying the developing solution stored in said developing tank to a sheet-like recording medium so as to develop an electrostatic latent image formed on the sheet-like recording medium; and a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head by a negative pressure effect, and subsequently circulating the developing solution into said developing solution tank, wherein said developing head comprises a rod-like base, a developing slit comprising an elongated opening formed in a surface of said rod-like base which corresponds to the sheet-like recording medium and said developing slit having a length smaller than a width of the sheet-like recording medium, a hollow portion, formed to be continuous with said developing slit, for receiving the developing solution from said developing solution tank, and a developing roller which is arranged in said hollow portion so as to be rotated while an outer surface of said developing roller opposes an opening end of said developing slit said developing roller capable of carrying the developing solution on the outer surface thereof; a developing roller including a magnetic material; a roller position regulating member arranged to allow a regulating surface thereof to come into contact with said outer surface of said developing roller at a predetermined position; and means for positioning said developing roller so as to allow said developing roller to be slidably rotated on the regulating surface such that said outer surface of said developing roller is magnetically attracted to the regulating surface of said roller position regulating member.

Claim 7

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head including a hollow case and a developing roller having an outer surface with a spiral groove formed in said outer surface, said hollow case having a developing solution supply port and a discharge port in a bottom portion thereof and having a developing slit in an upper surface thereof, and said developing roller being rotatably arranged in said hollow case while said outer surface of said developing roller which has said spiral groove formed thereon opposes a sheet-like recording medium through a small gap, and the outer surface of said developing roller opposes an opening end of said developing slit, whereby the developing solution stored in said developing solution tank is applied to the recording medium at a developing portion so as to develop an electrostatic latent image formed on the recording medium; a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head, and subsequently circulating the developing solution to said developing solution tank; a developing roller driving unit for rotating said developing roller to said developing head; a recording medium feed unit for conveying the sheet-like recording medium so as to cause the medium to pass over said developing head; and control means for controlling said suction pump, said developing roller driving unit, and said recording medium feed unit, wherein said control means controls rotation of said developing roller in a first mode during a developing operation and in a second mode, different from said first mode while said suction pump is operated to remove the developing solution from said outer surface of said developing roller upon completion of developing, and said control means controlling the conveyance of the sheet-like recording medium so as to remove the developing solution from a surface of the recording medium and dry said recording surface of the sheet-like recording medium.

Claim 8

A roller type liquid developing apparatus comprising: a developing solution tank for storing a developing solution in which charged fine color particles are dispersed; a developing head including a hollow case and a developing roller having an outer surface with a spiral groove formed in said outer surface, said hollow case having a developing solution supply port and a discharge port in a bottom portion thereof and having a developing slit in an upper surface thereof, and said developing roller being rotatably arranged in said hollow case while said outer surface of said developing roller which has said spiral groove formed thereon opposes a sheet-like recording medium through a small gap, and the outer surface of said developing roller opposes an opening end of said developing slit, whereby the developing solution stored in said developing solution tank is applied to the recording medium at a developing portion so as to develop an electrostatic latent image formed on the recording medium; a suction pump for pumping up the developing solution from said developing solution tank and supplying the solution into said developing head, and subsequently circulating the developing solution to said developing solution tank; a developing roller driving unit for rotating said developing roller to said developing head; a recording medium feed unit for conveying the sheet-like recording medium so as to cause the medium to pass over said developing head; and control means for controlling said suction pump, said developing roller driving unit, and said recording medium feed unit, wherein said control means controls rotation of said developing roller in a first mode during a developing operation and in a second mode, different from said first mode while said suction pump is operated to remove the developing solution from said outer surface of said developing roller upon completion of developing, and said control means controlling the conveyance of the sheet-like recording medium so as to remove the developing solution from a surface of the recording medium and dry said recording surface of the sheet-like recording medium.

Claim 9

An apparatus according to claim 4, further comprising means for stopping said developing roller and conveying the sheet-like recording medium upon completion of developing.

Claim 10

An apparatus according to claim 4, further comprising means for rotating said developing roller at a first speed during a developing operation and at a second speed lower than said first speed when developing is completed.

Claim 11

An apparatus according to claim 4, further comprising: a doctor blade which is arranged at a position of a developing solution level on the downstream side of the developing portion in a rotating direction of said developing roller; and means for rotating said developing roller in a first direction during a developing operation and in a second direction, opposite to said first direction, after developing is completed.

Claim 12

An apparatus according to claim 4, further comprising: developing solution forcibly removing means for forcibly removing a developing solution adhering to said outer surface of said developing roller; means for exposing an operating position of said developing solution forcibly removing means above a solution level upon completion of developing; means for rotating said developing roller in a direction in which a roller surface moves to the developing portion without moving from the exposed operating position of said developing solution forcibly removing means and passing through a position below the solution level; and means for continuously operating said suction pump during a period in which a portion of the sheet-like recording medium to which a developing solution adheres completely passes through a position of said developing head after a developing solution pool is removed from the developing portion.

Claim 13

An apparatus according to claim 8, further comprising: means for setting an operating position of said developing solution forcibly removing means on the roller surface to be above the developing solution level; means for rotating said developing roller in a first direction in which the roller surface passes through the operating position of said developing solution forcibly removing means and reaches the developing portion through a position below the developing solution level during a developing operation; and means for rotating said developing roller in a second direction opposite said first direction when developing is completed.

Claim 14

An apparatus according to claim 8, further comprising: solution level changing means for changing a developing solution level in said developing head; means for raising the developing solution level to a height enough to supply a developing solution to an outer surface of said developing roller during a developing operation by using said solution surface level changing means; and means for lowering the developing solution level to a position sufficiently lower than the operating position of said developing solution forcibly removing means upon completion of developing by using said solution level changing means.

Claim 15

An apparatus according to claim 8, further comprising: means for rotating said developing roller in a first forward direction during a developing operation so as to set the operating position of said developing solution forcibly removing means to a position lower than the developing solution level; and means for rotating said developing roller in a second direction opposite to said first forward direction upon completion of developing so as to set the operation position of said developing solution forcibly removing means to a position higher than the developing solution level.

Claim 16

A roller type liquid developing apparatus, in which the liquid developing apparatus develops a sheet-like recording medium having a given width and having an electrostatic latent image formed on a first surface thereof, comprising: a developing solution tank; a developing solution, having charged fine colored particles dispersed therein, stored in said developing solution tank; a developing head for applying said developing solution stored in said developing solution tank to said first surface of said sheet-like recording medium to develop said electrostatic latent image; and supply path means for supplying developing solution from said developing solution tank to said developing head; a pump for supplying suction pressure to suck up said developing solution from said developing solution tank into said supply path means and for supplying said suction pressure to said developing head and said first surface of said sheet like recording medium after said latent image is developed, to such up said developing solution used to develop said latent image back into said developing solution tank, and to immediately dry said first surface of said sheet-like recording medium; said developing head comprising: a rod-like base having a preselected length and at least one flat surface for mounting said sheet-like recording medium thereon; a hollow portion formed in said rod-like base along said preselected length of said rod like base; said hollow portion being provided with said suction pressure and receiving said sucked up developing solution from said supply path means; a developing slit including an elongated opening formed between said hollow portion and said at least one flat surface of said rod-like base for supplying developing solution to said first surface of said sheet-like recording medium, said developing slit also being provided with said suction pressure when said hollow portion is provided with said suction pressure; said developing slit having a length smaller than said width of said sheet-like recording medium; said developing slit being substantially sealed by said sheet-like recording medium when said sheet-like recording medium is mounted on said at least one flat surface of said rod-like base as said suction pressure of said pump sucks up said developing solution and said suction pressure is provided to said developing slit; a rotatable roller rotatable in a given direction mounted in said hollow portion, said rotatable roller including first and second end portions and a cylindrical surface formed between said first and second end portions; said roller being positioned in said hollow portion of said rod-like base adjacent said developing slit such that upon rotation of said developing roller in said given direction when said pump is sucking up said developing fluid and said sheet-like recording medium substantially seals said developing slit as a result of said suction pressure, said cylindrical surface of said roller carries at least some of said sucked up developing fluid to said first surface of said sheet-like recording medium, which is substantially sealing said developing slit, to develop said latent image;

Claim 17

A roller type liquid developing apparatus, in which the liquid developing apparatus develops a sheet-like recording medium having a given width and having an electrostatic latent image formed on a first surface thereof, comprising: a developing solution tank; a developing solution, having charged fine colored particles dispersed therein, stored in said developing solution tank; a developing head for applying said developing solution stored in said developing solution tank to said first surface of said sheet-like recording medium to develop said electrostatic latent image; and supply path means for supplying developing solution from said developing solution tank to said developing head; a pump for supplying suction pressure to suck up said developing solution from said developing solution tank into said supply path means and for supplying said suction pressure to said developing head and said first surface of said sheet like recording medium after said latent image is developed, to such up said developing solution used to develop said latent image back into said developing solution tank, and to immediately dry said first surface of said sheet-like recording medium; said developing head comprising: a rod-like base having a preselected length and at least one flat surface for mounting said sheet-like recording medium thereon; a hollow portion formed in said rod-like base along said preselected length of said rod like base; said hollow portion being provided with said suction pressure and receiving said sucked up developing solution from said supply path means; a developing slit including an elongated opening formed between said hollow portion and said at least one flat surface of said rod-like base for supplying developing solution to said first surface of said sheet-like recording medium, said developing slit also being provided with said suction pressure when said hollow portion is provided with said suction pressure; said developing slit having a length smaller than said width of said sheet-like recording medium; said developing slit being substantially sealed by said sheet-like recording medium when said sheet-like recording medium is mounted on said at least one flat surface of said rod-like base as said suction pressure of said pump sucks up said developing solution and said suction pressure is provided to said developing slit; a rotatable roller rotatable in a given direction mounted in said hollow portion, said rotatable roller including first and second end portions and a cylindrical surface formed between said first and second end portions; said roller being positioned in said hollow portion of said rod-like base adjacent said developing slit such that upon rotation of said developing roller in said given direction when said pump is sucking up said developing fluid and said sheet-like recording medium substantially seals said developing slit as a result of said suction pressure, said cylindrical surface of said roller carries at least some of said sucked up developing fluid to said first surface of said sheet-like recording medium, which is substantially sealing said developing slit, to develop said latent image;

Claim 18

The apparatus according to claim 12, in which said sheet-like recording medium moves across said at least one flat surface of said rod-like base in a given direction across said developing slit, further comprising: a liquid suction slit formed in said at least one flat surface of said rod-like base adjacent to said developing slit; said liquid suction slit having a bottom portion communicating with said hollow portion formed in said rod-like base; and an aperture, having a small sectional area formed between said bottom portion of said liquid suction slit and said pump to enable said liquid suction slit to suck up developing fluid on said at least one flat surface of said rod-like base.

Claim 19

The apparatus according to claim 12 in which said developing roller has a longitudinal axis, further comprising: a developing solution carrying spiral groove formed on said cylindrical surface of said developing roller forming peaks and valleys on said cylindrical surface, and which groove is substantially filled with said developing solution; said spiral groove having a predetermined groove pitch and being formed to support said first surface of said sheet-like recording medium on said peaks on said cylindrical surface; a line having a dimension l1 defining high density image forming regions on said sheet-like recording medium adjacent each of said peaks; the cross-sectional shape of said groove being formed such that said line having said dimension l1 measured along the sheet-like recording medium in a direction parallel to said longitudinal axis of said developing roller is defined to include all points on said recording medium having a distance between an inner wall of the groove and said first surface of the sheet-like recording medium which is not more than 0.2 mm; and the line having said dimension l1 is set to be not less than 1/2 of said predetermined groove pitch as measured along said longitudinal axis of said developing roller so that lines having said dimensions l1 around adjacent peaks will touch or overlap, thereby eliminating streaking resulting from low density developing regions between said peaks.

Claim 20

The apparatus according to claim 12, wherein said developing roller is formed of metal, further comprising energization means for energizing said developing roller to enable said developing roller to function as a developing electrode.

Claim 21

An apparatus according to claim 14, further comprising a developing roller having a spiral groove formed in a surface of a developing roller base, the groove comprising a multiple thread groove having a lead angle of not more than 30°.

Claim 22

An apparatus according to claim 14, further comprising a doctor blade which is arranged between a position of a downstream end portion of a developing portion in said developing slit in the rotating direction of said developing roller and a position where the outer surface of said developing roller escapes from a developing solution level to move toward an upstream end portion of the developing portion and is brought into contact with the top portion of the spiral groove of said developing roller.