Image forming device and computer which share the generation of a function for correcting image data based on an image forming condition of the image forming device

• US 6,046,820 A
• Filed: 10/22/1997
• Issued: 04/04/2000
• Est. Priority Date: 10/22/1996
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Konishi, Jun
• Primary Examiner(s): Evans, Arthur G.
• Application Number:
  US08/954,931
• Time in Patent Office: 895 Days
• Field of Search: 345/101, 345/106, 345/109, 345/114, 358/401, 358/406, 358/447, 358/448, 358/455, 358/456, 358/458, 358/461, 358/504, 358/518, 358/534, 358/1.1, 358/1.6, 358/1.9, 358/1.13, 358/1.15, 399/9, 399/15, 399/38, 399/53, 399/60, 399/72, 347/19, 347/188, 347/118
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/4078 using gradational references, e.g. grey-scale test pattern analysis

Abstract

A printer sends a calibration request to a computer upon sensing the need for calibration. Upon receiving the calibration request, the computer supplies the printer with data (logical density values) for a grayscale correction. On the basis of the grayscale correction data, the printer forms a sample image, measures the density (actual density values) of the sample image and notifies the computer of the actual density values. On the basis of the logical density values and actual density values, the computer creates a grayscale correction table (executes calibration) serving as a rule for correcting the tonality of image information. When printing is performed, the computer corrects the tonality of the image information based upon the grayscale correction table and supplies the corrected results to the printer.

Claims

1. An image output system comprising a host computer and a printer having a printer engine and a printer controller, said host computer and said printer being connected via a communication network, said printer comprising:

sensing means for sensing a change in environment;

calibration request transmission means for transmitting a calibration request to said host computer in accordance with the sensed result;

reception means for receiving sample image data from said host computer;

sample image forming means for forming a sample image based on the received sample image data;

measurement means for performing a measurement on the formed sample image; and

measured data transmission means for transmitting the measured data to said host computer; and

said host computer comprising;

calibration request reception means for receiving the calibration request from said printer;

sample image data transmitting means for transmitting the sample image data to said printer;

measured data reception means for receiving the measured data from said printer; and

generating means for generating grayscale correction data based on the received measured data.

4. The system according to claim 1, wherein the environment includes temperature or consumption of a component of said printer.

5. The system according to claim 1, wherein said printer adopts an electrophotographic method to form an image, said sample image forming means forms the sample image on a photosensitive drum, and said measurement means performs measurement on the sample image on the photosensitive drum.

6. The system according to claim 1, wherein said host computer further comprises:

correction means for correcting input image data in accordance with the generated grayscale correction data; and

image data transmission means for transmitting the corrected image data to said printer.

2. A printer having a printer engine and a printer controller, to be connected to a host computer calibrating grayscale correction data;

said printer comprising;

sensing means for sensing a change in environment;

calibration request transmission means for transmitting a calibration request to said host computer in accordance with the sensed result;

reception means for receiving sample image data from said computer;

sample image forming means for forming a sample image based on the received sample image data;

measurement means for performing measurement on the formed sample image; and

measured data transmission means for transmitting the measured data to said host computer.

3. The printer according to claim 2, wherein said calibration request transmission means transmits the calibration request to said host computer if an amount of change in the environment has exceeded a predetermined amount.

7. The printer according to claim 2, wherein the environment includes temperature or consumption of a component of said printer.

8. The printer according to claim 2, wherein said printer adopts an electrophotographic method to form an image, said sample image forming means forms the sample image on a photosensitive drum, and said measurement means performs measurement on the sample image on the photosensitive drum.

9. A host computer to be connected to a printer via a communication network, said printer having a printer engine and a printer controller, said host computer comprising:

calibration request reception means for receiving a calibration request transmitted from said printer based on a change in environment in said printer;

sample image data transmitting means for transmitting the sample image data to said printer;

measured data reception means for receiving data from said printer, the data being obtained by performing measurement on a sample image formed in said printer based on the sample image data; and

generating means for generating grayscale correction data based on the received data.

10. The host computer according to claim 9, wherein the environment includes temperature or consumption of a component of said printer.

11. The host computer according to claim 9, further comprising:

correction means for correcting input image data in accordance with the generated grayscale correction data; and

image data transmission means for transmitting the corrected image data to said printer.

12. A memory medium recording a program implementing an implementing an image processing method applied to a host computer to be connected to a printer via a communication network, the printer having a printer engine and a printer controller, the program comprising:

a calibration request reception step of receiving the calibration request transmitted from the printer based on a change in environment in the printer;

a sample image data transmitting step of transmitting the sample image data to the printer;

a measured data reception step of receiving data from the printer, the data being obtained by performing measurement on a sample image formed in the printer based on the sample image data; and

a generating step of generating grayscale correction data based on the received data.

13. A method applied to a host computer to be connected to a printer via a communication network, the printer having a printer engine and a printer controller, the method comprising:

a calibration request reception step of receiving the calibration request transmitted from the printer based on a change in environment in the printer;

a sample image data transmitting step of transmitting the sample image data to the printer;

a measured data reception step of receiving data from the printer, the data being obtained by performing measurement on a sample image formed in the printer based on the sample image data; and

a generating step of generating grayscale correction data based on the received data.