Electrophotography – Control of electrophotography process – Having temperature or humidity detection
Reexamination Certificate
2000-07-06
2003-04-01
Ngo, Hoang (Department: 2852)
Electrophotography
Control of electrophotography process
Having temperature or humidity detection
C399S097000, C399S066000, C399S068000, C399S396000
Reexamination Certificate
active
06542703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for improving the print quality of an image forming apparatus; and, more particularly, to a method for improving the print quality of an image forming apparatus capable of preventing the deterioration of the print image due to the change of the environment condition around the image forming apparatus by controlling the print speed of the image forming apparatus in case that the environment condition is at a low temperature and a low humidity when checked at the non-image stage of the apparatus.
2. Description of the Related Art
In general, facsimile, printer, and copy machines and a complex machine which performs these three functions, commonly have a printing function. All of them, therefore, essentially include an image forming apparatus for performing the printing function.
Such an image forming apparatus includes a paper cassette in which a plurality of papers as recording material are stacked. The papers stacked in the paper cassette are picked up and delivered, and an image is formed on the paper delivered through an image forming portion with dye such as toner. Then, the paper is output.
Typically, when activated, the image forming apparatus warms-up for a predetermined period depending on the property of the apparatus. When the warming-up is finished, the apparatus is converted to a on-line mode which can perform a print demand. If there is no print demand for a certain period at the on-line mode, the apparatus is converted from the on-line mode to a waiting mode. If the apparatus receives a print demand at the waiting mode, the apparatus performs the print operation by warming-up again. The warming-up, which is performed when the image forming apparatus is activated or receives a print demand in the waiting mode, means herein to pre-heat a transfer roller, a developing roller, a supplying roller and the like as well as an electrification roller of a printer engine actually performing the printing operation in the image forming apparatus by applying a predetermined voltage thereto.
However, since the above rollers are made of a conductive rubber material, the resistance of the rubber of the roller varies depending on the environment condition around the image forming apparatus. That is, since the temperature and the resistance of the rubber are in an inverse proportion relationship, the resistance of the rubber roller is increased in the case where the environmental condition around the image forming apparatus is a low temperature and low humidity condition.
Accordingly, since the respective rollers for forming a visible image by applying toner on an electrostatic latent image formed according to the externally received print data, transferring the visible image to a recording paper, and fixing the toner transferred to the recording paper, move the toner depending on the voltage difference applied to the rollers, if the resistance of each of the rollers increases under the external temperature or humidity, the amount of the toner applied to the electrostatic latent image decreases, thereby resulting in the deterioration of the image such as the decrease of the consistency of the image, the image contamination of non-image portion and the mistransfer. Such problems become even more severe in a mono developing roller system or a high speed developing system.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to provide an improved image formation process and apparatus.
It is another object to provide a process and apparatus for improving the print quality of materials produced.
It is still another object to provide a process and image forming apparatus capable of preventing the deterioration of the print image according to the change of the environment condition around the image forming apparatus by controlling the print speed of the image forming apparatus in case that the environment condition is at a low temperature and a low humidity when checked on at the non-image stage of the apparatus.
These and other objects may be attained in accordance with the principles of the present invention, with an image transfer process and apparatus that improves the quality of the printed images produced by the image forming apparatus by injecting toner onto an electrostatic latent image formed on a photosensitive drum according to print data received externally. The principles of the present invention contemplate the image forming apparatus storing in a memory the print data received externally and at the same time whether or not the environment condition around the image forming apparatus is at a low temperature and low humidity. When the environment condition is determined to be at a low temperature and low humidity, controlling the print speed of the image forming apparatus at a speed corresponding to the low temperature and low humidity environment; and printing the print data stored at the memory after the print speed is adjusted.
Preferably, the determining step includes detecting a resistance of a transfer roller of the image forming apparatus, and determining the environment to be at a low temperature and low humidity if the detected resistance change value is higher than a predetermined value.
Furthermore, the determining step includes measuring the internal temperature of the image forming apparatus, and determining the environment to be at a low temperature and low humidity if the measured temperature is increased above a predetermined value.
In addition, the print speed control step includes pre-storing a print speed corresponding to the resistance or temperature at the memory, picking up and setting the print speed corresponding to the detected resistance or temperature from the memory.
REFERENCES:
patent: 4618242 (1986-10-01), Yamagishi
patent: 5170215 (1992-12-01), Pfeuffer
patent: 5819149 (1998-10-01), Watanabe et al.
patent: 5887220 (1999-03-01), Nagaoka
patent: 6047144 (2000-04-01), Sasai et al.
patent: 11-129582 (1999-05-01), None
Bushnell , Esq. Robert E.
Ngo Hoang
Samsung Electronics Co,. Ltd.
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