Mita Industrial Co., Ltd.

Mita Industrial Co., Ltd. (a Corp. of Japan)

Kazuto Hori

Sadao Tanigawa

Hiroyuki Yoshikawa

Kazuhiro Ogawa

Yukihiro Aikawa

Tetsuo Tomiyama

Junichi Hirobe

Yoshiki Shimomura

Yasushi Umeda

Junichi Takamatsu

Yosuke Ohata

Eiichi Tone

Tomio Tada

Yuichi Koike

An image forming apparatus capable of detecting a toner image density well by shifting a developing bias. In adjusting a fog density or a solid density, the developing bias is shifted by a specified width so as to form an image of a gray density. This enables detection of the fog density and the solid density to be replaced with detection of a density in a gray density region where a reflection type photosensor can detect a density with high sensitivity. Thus, densities in a fog or solid density region where usually an output from the reflection type photosensor is saturated can be detected with high accuracy.

Image forming apparatus including improved toner image density detecting

The present invention is directed to an image density control device in an image formation apparatus where a pattern of reference density on a sample original is exposed to light from an exposing light source to image the pattern on photoconductor, density of the resultant toner image is detected by a reflection-type photosensor, and parameters on image density are adjusted based upon results of detection by the reflection-type photosensor. In the image density control device in the image formation apparatus, the sample original is mounted on a cabinet of the image formation apparatus so that a distance from the exposing light source in illuminating the pattern of the reference density to the pattern of the reference density can be adjusted.

Image density control device having an original mounting element with a

A method of controlling image density includes imaging a pattern of reference density as a toner image on a photoconductor. The density of the toner image is detected by a reflection-type photosensor, and parameters on the image density are adjusted based upon the results of this detection. In this invention, prior to measuring the reference density toner image, the drive current for the reflection-type photosensor is varied, and output from the reflection-type photosensor is measured while no toner is present on the photoconductor. A reference value of the drive current for the reflection-type photosensor which permits output from the reflection-type photosensor to be a predetermined value is determined. Then, the drive current for the reflection-type photosensor for measuring the reference density toner image is set based on the reference drive current value.

Method of controlling image density

An image forming apparatus has a functional redundancy system by which an inherent function normally performed by a certain portion is performed as a potential function by another portion, when such certain portion no longer can be perform its inherent function. In a first operative sequence, portions in the image forming apparatus perform their respective inherent functions. However, where a function of a certain portion in the apparatus is lost, for example, where a fault occurs and a particular element has failed, operation of other portions in the apparatus are controlled according to a second sequence. In the second sequence, the inherent function of the portion which has failed is replaced by the potential function of another portion in the apparatus.

Image forming apparatus having functional redundancy system

An image forming apparatus is provided with a rotatable photosensitive member; an imaging assembly for exposing the surface of the photosensitive member to light so as to form an electrostatic latent image thereon and developing the electrostatic latent image; and a sensor arranged in the vicinity of and opposed to the surface of the photosensitive member, and adapted for detecting an imaging performance in a specific region on the surface of the photosensitive member. With the image forming apparatus thus constructed, measurement values vary only within a reduced range since an imaging performance of the photosensitive member is detected in a specific region on the photosensitive member.

Image forming apparatus

A composite image forming apparatus including an analog or a digital image forming apparatus of the type in which an optical system moves relative to a document placed on a document table, the image on the document is scanned by the optical system and the image is transferred to a sheet of image transferring paper and a belt like recording medium on which additional or optional images from which additional or optional images other than the document image can be transferred to the sheet of image transferring paper.

Composite image forming apparatus

A device for detecting the life of a process unit which is detachably mounted in an image forming apparatus includes a sensor for detecting the density of the toner in the developing device and a signal detector receiving an output from the sensor and operable to determine whether the output exceeds or is less than a predetermined value during a predetermined time period which starts after a developing roller of the process unit starts rotating. A control is connected to the signal detector and is operable to effect different operating conditions depending on whether the output exceeds or is below the predetermined value, one of the operating conditions being an indication that the life of the process unit has expired and another of the operating conditions being an indication that the life of the process unit is unexpired.

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Osaka, Japan

Kazuto Hori