Liquid-type developing apparatus including developing head having hermetic structure

A liquid-type developing apparatus comprising:

• a developing head having a developing portion;
• a developing liquid container for containing a developing liquid;
• a suction pump;
• and
• a pipe for connecting said developing head, said developing liquid container, and said suction pump in a loop manner, and for circulating the developing liquid in said developing liquid container through said developing head in accordance with a drawing function of said suction pump;
• and
• sheet convey means for conveying a recording sheet on which an electrostatic latent image is formed while the recording sheet opposes said developing portion of said developing head, wherein
• said developing head comprises
• a hollow portion having a slit-shaped opening portion having as a longitudinal direction a direction perpendicular to a convey direction of the recording sheet,
• a partitioning wall for dividing said hollow portion into developing liquid flow-in and flow-out chambers and having a top portion located at said slit-shaped opening portion, and
• a belt-shaped plate member, disposed at said slit-shaped opening portion including at least said top portion of said partitioning wall, for constituting said developing portion, and
• said belt-shaped plate member has a plurality of windows disposed at a predetermined pitch to form stripes in the longitudinal direction of said slit-shaped opening portion such that a direction of said stripes is set oblique to the convey direction of the recording sheet.

A liquid-type developing apparatus comprising:

• a developing head incorporating developing liquid flow-in and flow-out chambers and having a slit-shaped opening portion communicating between said developing liquid flow-in and flow-out chambers;
• a developing liquid container communicating with said developing liquid flow-in chamber of said developing head through a developing liquid supply pipe;
• a suction pump, communicating with said developing liquid flow-out chamber of said developing head through a pipe, for causing said developing liquid flow-in chamber of said developing head to communicate with said developing liquid flow-out chamber of said developing head through said slit-shaped opening portion to supply the developing liquid contained in said developing liquid container therebetween;
• sheet convey means for conveying a recording sheet on which an electrostatic latent image is formed while the recording sheet opposes said slit-shaped opening portion of said developing head;
• outer air inlet path means, connected directly to said developing liquid flow-in chamber of said developing head, for supplying air to said developing liquid flow-in chamber independent of said developing liquid supply pipe;
• outer air valve means, located in said outer air inlet path means, for communicating with said developing liquid flow-in chamber through said outer air inlet path means;
• and
• control means for performing control to at least open said outer air valve means at a final step of development on the recording sheet.