Color printer having concurrent drop selection and drop separation, the printer being adapted for connection to a computer

• US 5,914,737 A
• Filed: 12/04/1996
• Issued: 06/22/1999
• Est. Priority Date: 04/12/1995
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Silverbrook, Kia
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US08/750,608
• Time in Patent Office: 930 Days
• Field of Search: 347/3, 347/48, 347/55, 355/38, 355/77, 358/298, 358/302, 358/502, 358/505
• US Class Current: 347/48
• CPC Class Codes: B41J 2/005 characterised by bringing liquid or particles selectively into contact with a printing material printing by selective application of impact or pressure on a printing or impression-transfer material B41J2/22
• CPC Class Codes: B41J 2/04 generating single droplets or particles on demand
• CPC Class Codes: B41J 2/14451 Structure of ink jet print heads discharging by lowering surface tension of meniscus

Abstract

A portable, high quality color printer for use with portable computers or in an office environment. The system uses a concurrent drop selection and drop separation drop on demand printing mechanism. The printer interprets information supplied by an external computer in the form of one or more page description languages (PDLs) to create a continuous tone page image. This image is converted to a bi-level image by digital halftoning, and stored in a bi-level page memory. The contents of the page memory can then be printed using the printing head. For use with notebook computers, a page width print head is used for fast, silent, low power operation and minimum size. The page width print head requires an entire page bitmap to be provided synchronously and at high speed. This is achieved by pre-calculating the bit-map on the notebook computer, and sending the data to the printer via a high data rate interface such as PC Cards.

Claims

1. A bi-level color printing apparatus including:

(a) a connection to a computer;

(b) a PDL interpreter;

(c) a digital halftoning unit which converts the continuous tone image data output by the PDL interpreter to bi-level image data;

(d) a bi-level page memory used to store at least one full page of bi-level data;

(e) a print head comprising;

(1) a plurality of drop-emitter nozzles,

(2) a body of ink associated with said nozzles,

(3) a pressurizing device adapted to subject ink in said body of ink to a pressure of at least 2% above ambient pressure, at least during drop selection and separation to form a meniscus with an air/ink interface,

(4) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles, and

(5) drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles; and

(f) a data distribution and timing system which provides the bi-level image data to the a print head at a correct time during a printing operation.

2. A bi-level color printing apparatus including:

(a) a connection to a computer;

(b) a PDL interpreter;

(c) a digital halftoning unit which converts the continuous tone image data output by the PDL interpreter to bi-level image data;

(d) a bi-level page memory used to store at least one full page of bi-level data;

(e) a print head comprising;

(1) a plurality of drop-emitter nozzles,

(2) a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle,

(3) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles, and

(4) drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles, said drop selection apparatus being capable of producing said difference in meniscus position in the absence of said drop separation apparatus; and

(f) a data distribution and timing system which provides the bi-level image data to the a print head at a correct time during a printing operation.

3. A bi-level color printing apparatus including:

(a) a connection to a computer;

(b) a PDL interpreter;

(c) a digital halftoning unit which converts the continuous tone image data output by the PDL interpreter to bi-level image data;

(d) a bi-level page memory used to store at least one full page of bi-level data;

(e) a print head comprising;

(1) a plurality of drop-emitter nozzles,

(2) a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle and said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30°

C. temperature range,

(3) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles, and

(4) drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles; and

(f) a data distribution and timing system which provides the bi-level image data to the a print head at a correct time during a printing operation.