Electrophotography – Machine operation – Job mode
Reexamination Certificate
1999-12-08
2001-02-20
Lee, Susan S. Y. (Department: 2852)
Electrophotography
Machine operation
Job mode
C358S001130, C358S001160, C358S296000, C358S404000, C358S444000, C399S085000
Reexamination Certificate
active
06192208
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing apparatus which includes an image forming means utilizing, for example, an electrophotographic process, a control method for the printing apparatus, and a computer-readable storage medium storing a control program for the printing apparatus.
2. Description of the Related Art
Page printers, primarily laser beam printers, have developed rapidly in recent years. More recently, a variety of page printers capable of outputting full-color images have also been proposed and commercialized.
In a color laser beam printer, a full-color image is formed by superimposing four images which are formed with the known electrophotographic process using toners of four colors. Various systems have been proposed for carrying out the electrophotographic process in a full-color fashion.
For example, an intermediate transfer system is known wherein a full-color image is formed by developing a latent image on a photoconductive drum into a toner image of each color, transferring each toner image to an intermediate transfer member successively to superimpose four-color toner images on the intermediate transfer member, and then transferring the four-color toner images to a sheet of paper at a time, followed by fusing the transferred images.
With such an intermediate transfer system, as shown in
FIG. 11
, toner images
1001
-
1004
of four colors, i.e., C (cyan), M (magenta), Y (yellow) and K (black, also denoted by Bk hereinafter), are successively formed on a photoconductive drum and transferred to an intermediate transfer member
1100
in superimposed relation. Then, the four-color toner images are transferred from the intermediate transfer member
1100
to a sheet of paper
1200
. Note that while the photoconductive drum and the intermediate transfer member each having a cylindrical shape are usually employed, image forming surfaces of those components are shown in a developed state in FIG.
11
and
FIG. 12
(described later).
The intermediate transfer system is advantageous in that since the positional relationship between the photoconductive drum and the intermediate transfer member is physically fixed, it is easier to avoid displacements of the four-color images than a system of transferring a toner image to a sheet of paper for each color without using the intermediate transfer member.
However, the image forming method based on the intermediate transfer system has such a problem that an intermediate transfer member having dimensions which correspond to a maximum size of sheet of paper available is required, and a throughput of printing is reduced when using sheets of paper smaller than the maximum size.
More specifically, as shown in
FIG. 12
, assuming that the maximum sheet size supportable by a printer is x×y, an intermediate transfer member also must have the size of x×y. The left side in
FIG. 12
represents the case in which an image is transferred from the intermediate transfer member
1100
to the sheet of paper
1200
having the maximum size. When the sheet of paper
1200
used has a size half the maximum one, i.e., (x×y)/2, only a half of the intermediate transfer member
1100
is employed to print one page.
In other words, the problem experienced in the intermediate transfer system is that when an image is formed in units of pages on each sheet of paper having a size smaller than the maximum one, the maximum number of sheets printable per minute cannot be increased over that obtained when printing images on sheets of paper having the maximum size no matter which size of paper is used in printing.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the problems set forth above, and to increase a throughput of the printing process in a printing system utilizing the electrophotographic process when a sheet of paper having a size smaller than the available maximum one is used.
Another object of the present invention is to solve the problem encountered when images for a plurality of pages (frames) are formed on an image carrier.
To achieve the above object, the present invention provides a printing apparatus, a control method for the printing apparatus, and a computer-readable storage medium storing a control program for the printing apparatus, the printing apparatus including an image forming unit which has an image carrier for holding an image, operates in a first image forming mode to form an image for a single page on the image carrier and in a second image forming mode to form images for a plurality of pages on the image carrier, and performs image formation in one of the first image forming mode and the second image forming mode. In the present invention printing data is received from an external device and the printing data is analyzed to obtain image data and image forming condition information in units of page. One of the first image forming mode and the second image forming mode is selected depending on the image forming condition information, thereby rendering the image formation to be performed in the selected mode.
The printing apparatus further includes a storage unit capable of storing the image data and the image forming condition information for a plurality of pages. The image data and the image forming condition information for two or more pages are stored in the storage unit, and one of the first image forming mode and the second image forming mode is selected in accordance with a result of determining whether plural data of the image forming condition information are the same for the two or more pages.
Preferably, the image forming condition information includes at least one of a paper feed unit for use in printing, a transport mode for one-side/both-side printing, a color mode, a paper ejection unit, an image size, a control parameter of an image forming process, a toner density, and resolution.
With the above features, superior advantages are obtained in that a throughput of the printing process can be increased to a maximum, and a printing output with high quality can be achieved.
Other superior advantages are that image forming conditions can be precisely reproduced as designated from an external device without causing undesirable errors, and the formation of images with high quality can be achieved.
Further, since the printing in the second image forming mode is allowed to run only when the various image forming conditions are matched, this ensures the superior advantages that the image forming conditions can be precisely reproduced as designated from an external device without causing undesirable errors, and the formation of images with high quality can be achieved.
Thus, according to the present invention, it is possible to increase a throughput of the printing process to a maximum, and achieve high quality of a printing output and speed-up of a printing process in the printing apparatus at the same time.
Other objects, features and advantages of the present invention will become more apparent from reading the following description with reference to the drawings.
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Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Lee Susan S. Y.
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