Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-06-22
2002-07-02
Barlow, John (Department: 2861)
Incremental printing of symbolic information
Ink jet
Controller
C347S023000
Reexamination Certificate
active
06412902
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing head inspecting device and method for a printer. More particularly, the present invention relates to a printing head inspecting device and method for a printer capable of quickly discovering failure in a printing head.
2. Description Related to the Prior Art
An ink jet printer is known, and includes an ink jet printing head, which includes a group of nozzles for ejecting ink to recording material to print an image thereto. If the ink jet printer is repeatedly used, choking of ink is likely to occur in the nozzles. It is likely that an ejected amount of ink decreases. Furthermore, no ink may be ejected. This causes streaks or other unevenness in color or density to occur in a printed image.
In general, an operator observes the printed image, and if there are streaks with unevenness in color or density, changes over the ink jet printer to a head cleaning mode. The printer is cleaned to eliminate the choking of ink or abnormality in a direction of ejecting the ink. In a cleaning process, ink is caused to flow out of the nozzles at a high flow rate. Also, the nozzles are sucked externally to remove choking of ink. Furthermore, the periphery of the nozzles is wiped. It is, however, likely that an operator discovers the choking of ink too late. Images may be printed at a low quality due to the failure. If the printer is used by a user at home, no serious problem occurs even with drop in the image quality. However, if the printer is used commercially at a printing shop, failure in operation of the nozzles may cause serious problem due to occurrence of a great number of failing prints to be produced.
Recently, the ink jet printing head has the nozzles arranged at a very high density so as to produce prints with high quality by means of pixels in a small size. There is a problem in that designation of failing nozzles becomes more difficult according to the high density of the nozzles.
SUMMARY OF THE INVENTION
In view of the foregoing problems, an object of the present invention is to provide a printing head inspecting device and method for a printer capable of quickly discovering failure in a printing head with great ease.
In order to achieve the above and other objects and advantages of this invention, a printing head inspecting device for a printer is provided, the printer including a printing head, having plural recording elements arranged in a first direction, and a moving mechanism for moving one of the printing head and recording material relative to remainder thereof in a second direction, to print at least one image to the recording material. In the printing head inspecting device, a controller causes the moving mechanism to set plural line positions of the recording material sequentially at the printing head, and while one of the plural line positions is set at the printing head, simultaneously drives recording elements in one group among plural groups into which the recording elements are grouped in the printing head, to print one check dot train to the recording material, thereby plural check dot trains being printed in the plural line positions, wherein each of the plural groups includes plural recording elements intermittently arranged in the printing head. An inspection sensor detects the plural check dot trains, to inspect whether the recording elements print at intended density.
In a preferred embodiment, a printing head inspecting device for a printer includes a controller for causing the moving mechanism to set the printing head sequentially to plural line positions in the recording material, and for, while the printing head is set in one of the line positions, driving the recording elements in such a manner that one of the recording elements is driven, and that n adjacent recording elements thereof per the one recording element are kept turned off according to the arranging direction, to print a check dot train to include one dot per one blank as large as n adjacent dots, where n is an integer equal to or more than 1, and for driving the recording elements in the manner with a difference in the line positions and a difference in the recording elements, to print first to (n+1)th check dot trains respectively to include one dot per one blank as large as n adjacent dots. An inspection sensor detects the first to (n+1)th check dot trains, to inspect whether the recording elements print at intended density.
The plural line positions are located upstream or downstream from the at least one image in the recording material.
The controller, according to an output from the inspection sensor, designates failing ones of the plural recording elements associated with pixels with the density being low in the plural check dot trains.
The at least one image is plural images, and the recording material is continuous recording sheet or recording sheet strip.
The inspection sensor includes plural photo receptor elements arranged in the crosswise direction, for reading the density of each of the plural check dot trains. Furthermore, a scanning mechanism moves the inspection sensor in the arranging direction, to scan the plural check dot trains by the pixels.
The plural photo receptor elements are arranged at a pitch of the plural check dot trains.
In a preferred embodiment, the inspection sensor includes a single photo receptor element. Furthermore, a scanning mechanism moves the inspection sensor in the arranging direction. While the recording material is moved in the crosswise direction, the inspection sensor scans the plural check dot trains on the recording material.
In another preferred embodiment, the inspection sensor includes plural photo receptor elements arranged in the arranging direction, for, while the recording material is moved in the crosswise direction, reading the density of the plural check dot trains by pixels.
The plural photo receptor elements are arranged at a pitch of the recording elements.
In a further preferred embodiment, the plural photo receptor elements are arranged at a pitch greater than a pitch of the recording elements. Furthermore, a scanning mechanism moves the inspection sensor in the arranging direction according to the pitch of the recording elements. While the recording material is moved in the crosswise direction, the inspection sensor scans the plural check dot trains on the recording material.
In an additional preferred embodiment, n=1, the first check dot train includes dots printed by recording elements of odd numbers among the recording elements, and the second check dot train includes dots printed by recording elements of even numbers among the recording elements.
In still another preferred embodiment, n=3, and the plural check dot trains are first to fourth check dot trains.
The printing head is an ink jet printing head, the recording elements are nozzles. The plural check dot trains are adapted to inspection of a state of the nozzles to eject ink.
According to another aspect of the invention, a printing head inspecting device includes a controller for causing the moving mechanism to set the printing head sequentially to plural line positions in the recording material, and for, while the printing head is set in one of the line positions, driving the recording elements in such a manner that m adjacent recording elements of the recording elements according to the arranging direction are driven, and that n of the recording elements per the m recording elements are kept turned off, to print a check dot train to include m adjacent dots per one blank as large as n dots, where m is an integer equal to or more than 2, and n is an integer equal to or more than 2 and equal to or more than m, and for driving the recording elements in the manner with a difference in the line positions and a difference in the recording elements, to print first to (n+1)th check dot trains respectively to include m adjacent dots per one blank as large as n dots. An inspection sensor detects the first to (n+1)th check dot trains, to inspect
Hosono Yasuyuki
Kaneko Kiyotaka
Kito Eiichi
Matsumoto Nobuo
Barlow John
Fuji Photo Film Co. , Ltd.
McGuireWoods LLP
Stewart Jr. Charles W.
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