Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2000-05-31
2002-12-03
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06488353
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus, which is provided with an image reading device, and can diagnose conditions of nozzles in a print head and an optical system in the image reading device.
2. Description of the Related Art
There have so far been provided a method, which is used for detection of a defect in the print head by a test pattern, and for visual check of the printed test pattern to see if any defect being occurred. However, this method may have a shortcoming that the results of a visual check differ according to each person's subjective point of view. For example, nozzle clogging may be overlooked, or sometimes such a magnifying glass as a loupe is needed.
In addition, Japanese Unexamined Patent Publication, No. 9-240017 discloses an art for detecting which nozzles are defective.
However, JPP 9-240017 lacks a special diagnostic function for an optical system. That is, the production of a high-quality image will not be able to expect when a defect occurs in a scanner portion as an image reading device. Since optical systems such as a scanner are usually covered, contamination adhered to an optical system cannot be visually checked. Further, a dedicated image reading means is needed for locating a defective nozzle.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming apparatus, which can detect a defect in a nozzle and an optical system.
Another object of the present invention is to provide an image forming apparatus in which a user is informed of an execution of maintenance.
According to the present invention, there is provided an image forming apparatus comprising: a scanner which reads an image and a print head which prints an image; a head control unit which controls the print head to print a test pattern with the print head; and an image processing unit which diagnoses a defect in the print head and the scanner by processing data of the test pattern which is read by the scanner.
The image forming apparatus according to the present invention have the following exceptional advantages.
(i) Starting a test pattern printing operation by the head control unit, in response to power switch-on, a print start command input from a user, or a demand of a user allows a printing operation to perform in a good condition. Even if the situation where a defect in the ink jet nozzle or contamination adhered to the optical system is caused by having been left unused for a long time.
In addition, it allows image degradation to avoid in an unusual situation.
(ii) Printing a test pattern repeatedly by the head control unit, or reading it repeatedly by the scanner permits accuracy of the results of comparing processing to enhance.
In addition, determining whether a defect is occurred in the nozzle in the print head or the optical system of the scanner by the image processing unit permits a proper countermeasure to take according to where a defect occurs and what is a cause therefor.
(iii) Providing a display unit for displaying a command to clean the ink nozzle when the image processing unit determined a defect to be occurred in the ink nozzle system enables a user to prompt to input a command.
In addition, locating a defect in the ink nozzle by the image processing unit when a defect is occurred, and providing a cleaning unit for cleaning the nozzle with respect to defective portions enables the amounts of ink needed for cleaning the nozzle and time required for cleaning operation to reduce, with the minimum cleaning operation.
(iv) Providing the display unit for displaying a command to perform maintenance of the optical system when the image processing unit determined a defect to be occurred in the optical system of the scanner makes it possible to prompt a user to perform maintenance of the optical system.
In addition, locating a defect in the optical system when a defect is occurred in the optical system by the image processing unit, and providing the display unit for displaying defective portions makes it possible to reduce the time required for cleaning operation with the minimum cleaning operation.
REFERENCES:
patent: 4493993 (1985-01-01), Kanamuller et al.
patent: 5140429 (1992-08-01), Ebinuma et al.
patent: 5534895 (1996-07-01), Lindenfelser et al.
patent: 5963225 (1999-10-01), Sugiyama
patent: 6373983 (2002-04-01), Tsai
patent: 09240017 (1997-09-01), None
Itoyama Motoyuki
Mizuyama Yoshio
Suzuki Michiyuki
Barlow John
Huffman Julian D.
Renner Otto Boisselle & Sklar
Sharp Kabushiki Kaisha
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