Sharp Kabushiki Kaisha Corporation

Masayasu Narimatsu

Jitsuo Masuda

Hiroshi Kawamoto

Kiyofumi Morimoto

Toshihisa Ishida

Hiroo Naoi

Motoyuki Itoyama

Hideji Saiko

Hideji Saikoh

Mitsuru Tokuyama

Toshiaki Ino

Kazuma Hinoue

Katsuaki Sumida

Kohichi Takenouchi

Takeshi Ohkawa

Yuichiro Takesue

Makoto Uehara

Ken Yamagishi

Tomoko Nishino

Naoki Fukudo

Yuka Sakagami

Junichi Saito

Masahiro Sakai

Yasutaka Maeda

Katsuhiro Nagayama

Eiichi Kido

Takayuki Yamanaka

Takashi Kitagawa

Masato Asanuma

Hiroaki Yoshida

Yasuo Kitabatake

Tomoki Minamikawa

Tomoe Matsuoka

Kanshiro Okamoto

Eisaku Hatanaka

Masakatsu Hayashi

Hiroji Kawamoto

Provided are an image forming apparatus that, when a difference between a developing bias in correcting an image density and a reference developing bias has a value not less than a prescribed value that is set preliminarily, replenishes or consumes a toner forcibly, executes correction of the image density again, and controls the developing bias in such a manner that a toner density is controlled to fall within an appropriate range, and an image forming method using the same. When a difference between a developing bias value after correction of the image density and the reference developing bias becomes larger than the prescribed value to the plus side or the minus side, a toner density control portion performs control to consume or replenish a toner forcibly.

Image forming apparatus, and image forming method

An image forming apparatus includes: a developing device; a toner supply device; and a toner supply detecting sensor; and a toner concentration controller that directs toner supply. The toner concentration controller includes: a memory that stores the difference between the outputs from toner supply detecting sensor before and after toner supply; a toner supply quantity determinater that determines that the amount of toner remaining in the toner supply device is low and the amount of toner supply is low when the output difference or output ratio of the sensor is lower than a supply reference value; and an image quality adjustment controller that shortens the interval of time between adjustment of electrical potential on toner concentration correction in the above case.

Toner concentration controller and image forming apparatus including the toner concentration controller

An image forming apparatus includes a developing device having a toner supply sensor, a toner supply device supplying toner to the developing device, a toner supply controller controlling toner supply from the toner supply device to the developing device based on predetermined conditions, a toner empty determiner determining whether toner is present inside the toner supply device. In the image forming apparatus, the toner supply device includes a storage for recording multiple measured values of toner supply detected by the toner supply sensor, and the toner supply controller corrects the amount of toner supply, based on the moving average of multiple measured values of the amount of toner supply.

Image forming apparatus and toner supply method

An image forming apparatus includes: a latent image bearing member on which an electrostatic latent image is to be formed; a developing unit which contains the developer and performs a development process to develop the electrostatic latent image formed on the latent image bearing member; and a movement mechanism which moves the developing unit toward the latent image bearing member when the development process is performed, and moves the developing unit away from the latent image bearing member and changes the attitude of the developing unit with, respect to the latent image bearing member when the development process is not performed.

Image forming apparatus with movable developing unit

An image forming apparatus and a method for cleaning a photoreceptor are realized that allow cleaning a surface of the photoreceptor to eliminate foreign substances adhering thereto, without using a special abrasive sheet. A recording sheet is fed and brought into contact with photoreceptors of all photoreceptor drums. The recording sheet is stopped by causing the vicinity of a rear end of the recording sheet to be sandwiched between a pair of registration rollers. Then, the photoreceptor drums are rotated. By this way, the cleaning is carried out to the photoreceptor.

Image forming apparatus capable of cleaning a photoreceptor, method for cleaning a photoreceptor, and computer program for causing an image forming apparatus to clean a photoreceptor

In case of a developing density correction based on a test image (patch image) density, normally, the developing density is carried out in a short period of time by correction (&#x3b3; correction) of a developing bias and a grid voltage (S). When a correction amount of the &#x3b3; correction exceeds an ordinary range, the &#x3b3; correction (S) and adjustment of toner concentration (magnetic permeability reference value) (S) are carried out in combination. Furthermore, when the toner concentration is changed, the setting of a correction reference of the &#x3b3; correction (&#x3b3; correction TBL) and correction timing of the &#x3b3; correction are accordingly changed (S, S). Therefore, in the developing density correction based on the test image density in the developing device using binary developer, it is possible to carry out the developing density correction, which is carried out in a short time, and whose correction width is wide, while maintaining the accuracy of a developing density adjustment.

Developing device, image forming device equipped therewith, and developing density adjusting method

An object of the invention is to make an exact judgment on suitability of a replaceable component such as a toner supplying container with use of an existing mechanism of an image forming apparatus, without additionally providing a data storage component designed for a consumable product which is detachably attached to the apparatus, or a data reading component to be placed in the image forming apparatus main body. In an incorporated control section, a specific part of a replaceable component, which is placed on an original platform prior to being loaded into the apparatus, is optically scanned to read image information, and, based on the reading result, whether or not the replaceable component is suitable for the image forming apparatus is judged.

Image forming apparatus and method for determining suitability of replaceable component

The object of this invention is to provide an image forming apparatus capable of preventing decrease in image density at a rear end part of an image. A change in waveform in sensor outputs which is produced when a toner patch image is read by an optical sensor used for the process control is detected. The difference (Vg&minus;Vd) between grid voltage Vg and development bias voltage Vd is changed only between a target value of 300 V corresponding to low-output side threshold value Va and a target value of 100 V corresponding to high-output side threshold value Vb according to the sensor output deflection &Dgr;V so that the difference (Vg&minus;Vd) decreases as the image loss level increases. The difference between the grid voltage Vg and the development bias voltage Vd is set so as to prevent the image loss in the rear end part of an image.

Image forming apparatus with automatic density compensation

An image forming apparatus including a developing unit for stocking a developing agent containing toner and forming a toner image on a photosensitive medium with the developing agent, a toner supply unit for supplying the toner to the developing unit, a toner specific concentration detecting unit for detecting the toner specific concentration of the developing agent stocked in the developing unit, a humidity detecting unit for detecting humidity in the neighborhood of the developing unit, a storage unit for storing the humidity information detected by the humidity detecting unit, and a toner specific concentration correcting unit for controlling the toner supply amount of the toner supply unit on the basis of the humidity information stored to correct the toner specific concentration, wherein the toner specific concentration correcting unit compares newly-detected humidity with reference humidity corresponding to the humidity which is detected at the time when the developing agent is stocked into the developing unit or exchanged by new developing agent and which is stored in the storage unit, and corrects the toner specific concentration in accordance with the comparison result.

Image forming apparatus having humidity detection and toner concentration adjusting according to detected humidity

An image forming apparatus has an arrangement wherein a main charger includes a charger line corresponding to a region within a reference range on a surface of a photoreceptor and second charger lines corresponding to regions outside the reference range, and the first charger line within the reference range and the second charger lines outside the reference range are driven independently. The reference range is set on the surface of the photoreceptor as a width of a transported sheet which is most frequently used. In a processing control, in the case where toner patch density within the reference range becomes higher than toner patch density outside the reference range, an applied voltage with respect to the charger line within the reference range is increased relatively higher than an applied voltage with respect to the charger lines outside the reference range, thus uniformalizing the toner density with respect to the entire surface of the photoreceptor drum.

Image forming apparatus for controlling processing conditions in image

The image forming apparatus of the invention controls the toner density by any one of the following configurations: by correcting the toner density of the developer in association with the agitation total; by controlling a process parameter so that the density of a toner patch formed on the photoreceptor corresponds to a prescribed density value and determining that developing performance of the developer is improved and canceling the toner density correction when the process parameter reaches the prescribed value; by changing the toner density reference value when the variation as to the charger output is equal to or greater than a first predetermined value and maintaining the changed toner density reference value until the variation of the charger output again becomes equal to or greater than the first predetermined value; or by prohibiting toner supply for a constant duration to prevent excessive toner supply if time from the end of the last operation of the developing unit to the start of a next operation, inclusive of the power-activation is equal to or longer the a predetermined period when the developing unit is activated to commence agitation of the developer.

Toner density control for an image forming apparatus

CPU is designed to create toner patches on the surface of the photoreceptor drum and pick up the detected data of the density of the toner patches by a photosensor. CPU calculates a correcting value .DELTA.Vg of the charger output in accordance with the picked up detected data, and compared the corrected charger output Vg with (Vgs+.alpha.) and (Vgs-.alpha.). If the corrections in the same direction are repeated in a row, k.beta. (where 0&lt;k&lt;1) is added to or subtracted from the toner density reference value. When the direction of the correction for the toner concentration reference value to be made is opposite that of the previous one, the absolute value of the correcting value for the current correction is set to be the absolute value of the previous one.

Image stabilizing method for use in an image forming apparatus

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Nara, Japan

Masayasu Narimatsu