Image forming apparatus and method

• US 5,655,185 A
• Filed: 06/07/1995
• Issued: 08/05/1997
• Est. Priority Date: 08/27/1991
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suzuki, Hideki, Takubo, Takefumi, Akiyama, Satoshi, Hori, Kenjiro
• Primary Examiner(s): Smith, Matthew S.
• Application Number:
  US08/478,661
• Time in Patent Office: 790 Days
• Field of Search: 355/246, 355/214, 355/203, 355/204, 355/208, 355/200, 355/202, 358/296, 358/298, 358/300, 399/138, 399/72
• US Class Current: 399/138
• CPC Class Codes: G03G 15/5041 Detecting a toner image, e.g. density, toner coverage, using a test patch G03G15/553 takes precedence
• CPC Class Codes: G03G 2215/00042 Optical detection
• CPC Class Codes: G06K 15/1214 by feedback
• CPC Class Codes: G06K 2215/0082 Architecture adapted for a particular function
• CPC Class Codes: H04N 1/295 Circuits or arrangements for the control thereof, e.g. using a programmed control device, according to a measured quantity
• CPC Class Codes: H04N 1/4078 using gradational references, e.g. grey-scale test pattern analysis

Abstract

The present invention has an object to provide an image forming apparatus and method which enables an operator to easily adjust to the desired printing density. A paper feeding roller is driven in timing along with a registration roller. The irradiation of a modulated laser beam is started, a developing high-voltage is changed from "0" V to a predetermined voltage V1, and the voltage is changed to V2 at other timings. By sequentially changing the voltage in this manner, the printing densities from laser modulating data d1 to d10 are adjusted and printing in different densities can be performed.

Claims

1. An image forming apparatus comprising:

image forming means for successively performing a plurality of image forming operations, page by page, each image forming operation forming an image having an image density;

density instruction input means for inputting a density instruction;

density control means for controlling said image forming means to form an image having an image density corresponding to a density instruction input by said density instruction input means,

wherein, when a density instruction is input during a current image forming operation, said density control means controls said image forming means so that at least the current image forming operation is performed in accordance with an existing density instruction, and then controls said image forming means to perform a successive image forming operation to form an image having an image density corresponding to the density instruction input by said density instruction input means; and

image data input means for inputting image data received from an image data source, wherein said image forming means forms an image corresponding to input image data, and

wherein, when a density instruction is not input to said density instruction input means with image data received from the image data source, said density control means controls said image forming means so as to form an image corresponding to image data input by said image data input means at a default image density.

2. The apparatus according to claim 1, wherein said image data input means is capable of receiving input image data from a plurality of image data sources, and wherein said control means controls said image forming means to perform a respective plurality of image forming operations to form respective images having respective image densities independently for each image data source.

3. The apparatus according to claim 1, wherein said density instruction input means includes manual input means operable during an image forming operation, and wherein said density control means comprises first storing means for storing a density instruction input to said density instruction input means with image data received from an image data source, and second storing means for storing a density instruction manually input through said manual input means as the default image density, and wherein the first storing means is cleared in response to completion of an image forming operation forming an image having an image density corresponding to the density instruction stored in the first storing means.

4. The apparatus according to claim 3, wherein said second storing means is an NVRAM.

5. The apparatus according to claim 1, wherein said image forming means comprises means for forming an electrostatic latent image and means for developing the electrostatic latent image into a visible image.

6. The apparatus according to claim 1, wherein said image forming means comprises means for scanning a photosensitive member with a light beam modulated by at least one of an image signal and a test pattern signal.

7. The apparatus according to claim 1, further comprises code conversion means for converting code information into dot data, and wherein said image data inputting means inputs code information as image data.