Electrophotography – Diagnostics – By inspection of copied image
Reexamination Certificate
2000-03-20
2001-09-18
Chen, Sophia S. (Department: 2852)
Electrophotography
Diagnostics
By inspection of copied image
C399S072000, C399S075000, C399S384000
Reexamination Certificate
active
06292635
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a continuous medium printing apparatus for printing data to be printed on a continuous medium such as a continuous recording paper by using an electrophotograph, for example.
(2) Description of Related Art
There are known several kinds of systems in which image data is printed on a continuous medium (hereinafter sometimes referred to as continuous paper or simply paper). One of these system, or an electrophotograph system is very popular because of its low cost.
FIG. 46
is a schematic diagram of a continues medium printing apparatus in which an electrophotograph system is employed. As shown in
FIG. 46
, data to be printed sent from an upper controller unit
93
is supplied to a mechanism control unit
91
provided within a printer
90
, in which the data to be printed is transferred to a photosensitive body drum (photosensitive drum)
90
e
by an exposing unit
90
d.
In this case, the photosensitive drum
90
e
is rotated in the clockwise direction in FIG.
46
. Initially, the photosensitive drum
90
e
has charged its surface uniformly by a pre-charging device
90
c.
When the photosensitive drum
90
e
is exposed under light by the exposing unit
90
d
, then an electrostatic latent image corresponding to the data to be printed is formed on the surface of the photosensitive drum
90
e.
The electrostatic latent image is developed by a developing device
90
g
so as to form a toner image. The toner image on the surface of the photosensitive drum
90
e
is transferred to the paper by means of a transfer electrifying device
90
f
and a conveying body
30
i.
Thereafter, residual toner is removed by a cleaner unit
90
b.
The photosensitive drum
90
e
has again its surface electrified uniformly by the pre-charging device
90
c
so that the photosensitive drum
90
e
can cope with the next step of transfer process. Meanwhile, continuous paper
92
is conveyed by a conveying tractor (paper conveying mechanism)
90
h.
When the paper reaches a place beneath a fixing device
90
a,
the transferred toner image is fixed by heat applied by the fixing device
90
a.
The paper printed with the image thereon is reserved within a continuous paper reserving unit.
When the printer
90
prints data to be printed supplied from the upper controller unit
93
, sometimes a print image drop, a dirt spot or the like occurs due to a folding portion of the continuous paper
92
. Therefore, it is necessary for an operator of the printer to check the printed image so that the printing operation can be continued or the dirt spot or the like can be detected even if the image drop or the dirt spot is caused in the printed image.
To this end, there has been proposed an apparatus in which an image having been printed on the continuous paper is read by a reading apparatus, and the printed image data read by the reading apparatus and data to be printed are compared with each other. According to the apparatus, comparison is made by detecting the correspondence between the predetermined paper size and the data to be printed. Proposes with regard to the apparatus can be found in the following five kinds of publications.
Initially, in Japanese Patent Laid-Open Publication No. HEI 7-81191 (hereinafter referred to as a publication 1), there is disclosed a printer equipped with a print result comparing function by which it is determined automatically and at a high speed, whether the printer produced a print result correctly or not. According to the technology disclosed in the publication 1, the printer includes a picked-up area designating means
32
by which an area to be compared with data to be printed is designated from data read as printed image data. The data of the area designated by the picked-up area determining means
32
is recognized as picked-up characters and subjected to the comparison.
In Japanese Patent Laid-Open Publication No. HEI 6-237350 (hereinafter referred to as a publication 2), there is disclosed a facsimile apparatus in which when printing error is detected, causing an error, only the page containing the error is again printed so that the print error is recovered. According to the technology disclosed in the publication 2, the printed text data is read by some device provided in the facsimile apparatus, subjected to check, and a print retrying request is issued on the page containing the error so that printing of the page is retried.
Next, in Japanese Patent Laid-Open publication No. HEI 9-216441 (hereinafter referred to as publication 3), there is disclosed an image defect detecting apparatus in which a defect of a printed image can be positively detected with a short period of time. According to the technology disclosed in the publication 3, image data extracted on the basis of position information about an important area out of image data read in an optical manner, is subjected to comparison with original image data offered to printing, and if it is determined that both the data are not coincident to each other, a defect detecting signal is generated. In this case, there are introduced three methods for attaching the position information of the important area. That is, a method in which a position information is registered in advance, a method in which image data to be attached with the position information is extracted from Page Description Language, and a method in which a shading composed of code information containing the position information of the important area is detected so that it is determined whether the shading of the image is dropped or not.
Further, in Japanese Patent Laid-Open Publication No. HEI 3-36071 (hereinafter referred to as a publication 4), there is disclosed a printer apparatus in which printed result and print data are compared with each other so that error printing can be detected. According to a phase difference control circuit introduced in the publication 4, control is carried out by taking into account the correction on a time it takes for a paper to travel from a printing position to a data reading device. In this way, print error can be detected and reliability in printing operation can be guaranteed at a very high level.
Furthermore, in Japanese Patent Laid-Open Publication No. HEI 8-25764 (hereinafter referred to as a publication 5), there is disclosed a printer apparatus in which print error can be corrected solely by the printer apparatus and number of times of print retrying is restricted. According to the technology disclosed in the publication 5, print error can be corrected in the printer apparatus, so that load of error processing imposed on an apparatus governing the printer apparatus is relieved and efficiency of channels is improved so that error correction process can be carried out for a short period of time. Moreover, the printer apparatus is provided with a counter for restricting the number of times of print retrying so that time consumption in the print retrying is limited to a predetermined level.
Incidentally, when printing is carried out on continuous paper by using these printer apparatus, these printers are placed in a situation in which a plurality of printers are connected to a single printer line so that each printer prints on paper of a different size at a different resolution. Further, data to be printed sent from a controller unit governing the printer apparatus is printed continuously by the plurality of printers. Furthermore, a single printer can print the data on paper of a plurality of sizes at a plurality of resolution levels. Therefore, according to the technologies disclosed in the publications 1 to 5, when each of the plurality of printers prints the data on paper of each different size at each different resolution level, comparison between the data to be printed and actually printed data cannot be carried out in accordance with the paper size and resolution level in each printer.
In addition to the above drawback, when so called loading operation is carried out, i.e., continuous paper is loaded in the printer and the compari
Nishiura Tamotsu
Shimizubata Amiko
Sugisaki Eiichi
Tokairin Motohiro
Armstrong Westerman Hattori McLeland & Naughton LLP
Chen Sophia S.
Fujitsu Limited
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