Image forming apparatus, and memory control method for image forming apparatus

• US 6,839,075 B2
• Filed: 01/14/2002
• Issued: 01/04/2005
• Est. Priority Date: 01/19/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sato, Isamu
• Primary Examiner(s): PHAM, HAI CHI
• Application Number:
  US10/043,126
• Publication Number:
  US 20020097318A1
• Time in Patent Office: 1,086 Days
• Field of Search: 347/175, 347/176, 347/215, 347/221, 347/235, 347/250, 347/262, 347/264, 347/234, 347/248, 358/1.16, 358/1.2, 358/1.6, 358/1.18
• US Class Current: 347/235
• CPC Class Codes: G06K 15/1257 on more than one main scanning line
• CPC Class Codes: G06K 2215/0077 Raster outputting to the print element(s)

Abstract

This invention obtains an image forming apparatus and image forming method capable of achieving a simple, low-cost arrangement by controlling memory write-in/read-out similarly to image signal generation using a single beam even when an image is formed using a plurality of light beams. Write-in of a first light beam image signal in a memory A starts before a first light beam image signal for previous scanning is completely read out from the memory A. Write-in of a second light beam image signal in a memory B starts after a second light beam image signal for previous scanning is completely read out from the memory B.

Claims

1. An image forming apparatus comprising:

scanning means for scanning a photosensitive member with a first light beam and a second light beam;

a first memory for storing an image signal for modulating the first light beam;

a second memory for storing an image signal for modulating the second light beam; and

memory control means for starting writing an image signal for a first light beam in said first memory before an image signal for a first light beam for previous scanning is completely read out from said first memory, and starting writing an image signal for a second light beam in said second memory after an image signal for a second light beam for previous scanning is read out from said second memory.

2. An apparatus according to claim 1, wherein said memory control means controls the memory write-in so as not to simultaneously execute the write-in of said image signal for a first light beam and the write-in of said image signal for a second light beam.

3. A memory write-in control method for an image forming apparatus having

scanning means for scanning a photosensitive member with a first light beam and a second light beam,

a first memory for storing an image signal for modulating the first light beam, and

a second memory for storing an image signal for modulating the second light beam, comprising the steps of:

starting write-in of an image signal for a first light beam in the first memory before an image signal for a first light beam for previous scanning is completely read out from the first memory; and

starting write-in of an image signal for a second light beam in the second memory after an image signal for a second light beam for previous scanning is read out from the second memory.

4. A method according to claim 3, wherein the first light beam image signal write-in step and the second light beam image signal write-in step are not simultaneously executed.