The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 05, 1999
Filed:
Nov. 02, 1995
Shigeru Inose, Sowamachi, JP;
Fumio Miyahara, Sagamihara, JP;
Hideaki Kishida, Kawasaki, JP;
Yasuhiro Hamada, Yokohama, JP;
Canon Aptex Inc., Mitsukaido, JP;
Abstract
In a color printer, in order to perform a high-speed print operation and ensure a refresh operation and the like of an image memory, print images which correspond to a plurality of printheads, and are bitmapped and stored in a bitmap RAM in units of colors are consecutively read out and DMA-transferred by 16 bits at a time when a read operation is designated. After this DMA operation, the refresh operation of the bitmap RAM or access to the RAM is permitted. The printer includes the same number of latch circuits as that of printheads (e.g., four). Each latch circuit stores a data transfer start address (TOPA) and a data transfer end address (ENDA) in the bitmap RAM. With this arrangement, image data can be efficiently read out. If the capacity of the bitmap RAM is small, an upper address bit in the bitmap RAM is shifted to switch discontinuous addresses to continuous addresses on the bitmap memory side. If an optional memory is implemented, the normal addressing is restored to flexibly cope with a change in the capacity of the image memory.