Printhead substrate having a mixture of single and double sided elongate ink feed channels

An ink jet printing apparatus comprising:

• a printhead substrate including a plurality of thin film layers, said printhead substrate having a first longitudinal side and a second longitudinal side opposite said first longitudinal side;
• a single-edge feeding ink feed slot formed in said printhead substrate and having a first longitudinal edge and a second longitudinal edge opposite said first longitudinal edge;
• a double-edge feeding ink feed slot formed in said printhead substrate and having a first longitudinal edge and a second longitudinal edge opposite said first longitudinal edge;
• a first group of ink drop generators located adjacent said first longitudinal edge of said single-edge feeding ink feed slot and receiving ink from said single-edge feeding ink feed slot, wherein no ink drop generators are disposed adjacent said second longitudinal edge of said single-edge feeding ink feed slot and wherein said single-edge feeding ink feed slot supplies ink only to said first group of ink drop generators;
• a second group of ink drop generators located adjacent said first longitudinal edge of said double-edge feeding ink feed slot and receiving ink from said double-edge feeding ink feed slot;
• and
• a third group of ink drop generators located adjacent said second longitudinal edge of said double-edge feeding ink feed slot and receiving ink from said double-edge feeding ink feed slot.

A method of printing comprising the steps of:

• emitting ink drops from a first plurality of ink drop generators defined in a printhead substrate;
• supplying ink to the first plurality of ink drop generators through a first ink feed slot having such first plurality of ink drop generators adjacent a first edge of the first ink feed slot and having no ink drop generators adjacent a second edge that is opposite the first edge;
• emitting ink drops from a second plurality of ink drop generators defined in the printhead substrate;
• supplying ink to the second plurality of ink drop generators through a second ink feed slot having such second plurality of ink drop generators adjacent a first edge of the second ink feed slot and having no ink drop generators adjacent a second edge that is opposite the first edge;
• emitting ink drops from a third plurality of ink drop generators defined in the printhead substrate;
• supplying ink to the third plurality of ink drop generators through a third ink feed slot having such third plurality of ink drop generators adjacent a first edge of the third ink feed slot;
• emitting ink drops from a fourth plurality of ink drop generators defined in the printhead substrate;
• and
• supplying ink to the fourth plurality of ink drop generators through the third ink feed slot having such fourth plurality of ink drop generators adjacent a second edge of the third ink feed slot that is opposite the first edge thereof.