Mita Industrial Co., Ltd.

Junichi Takamatsu

Kazunori Akiyama

Tomio Tada

Yukihiro Aikawa

Junichi Hirobe

Masami Taniguchi

Tsutomu Sugaya

Kazuto Hori

Makoto Okado

Akiyoshi Tanizawa

An image forming apparatus which forms a toner image which is transferred onto a copy sheet includes a fixing unit having a heater for fixing the toner image onto the copy sheet at a predetermined fixing temperature. A cooling unit operates at a first cooling state for cooling the fixing unit. A mode selector is provided for setting a mode of the image forming apparatus to an energy saving mode in which heating operation by the heater is halted. A cooling controller suspends cooling operation of the cooling unit after a delay following a time when the image forming apparatus is set to the energy saving mode.

Image forming apparatus with time delayed cooling control

The toner density control device of the invention is adapted to an image forming apparatus in which a plurality of processes for image formation are executed, and includes a toner sensor for detecting toner density in a developing section of the image forming apparatus, toner supplying means for supplying toner to the developing section according to output of the toner sensor, and cancelling means for temporarily cancelling function of the toner supplying means or output of the toner sensor in response to switching of operations in the process for image formation. Even if a meachanical vibration is generated during switching of operations in the process for image formation, the function of the toner supplying means or the output of the toner sensor is temporarily cancelled, so that an erroneous detection of toner density or inappropiate toner density control based on the aforesaid errorneous detection can be avoided. Accordingly, it is possible to prevent such a drawback that the density of a formed image becomes too dark or too weak in places due to mechanical vibration in the process of the image formation.

Toner density control device

An image-forming machine, such as an electrostatic copying machine, having a number of optional features. A display device is provided for displaying the number or type of toner cartridge loaded in the main body of a developing device. An image-forming condition adjusting device is provided for adjusting the image-forming conditions in response to a toner cartridge loaded in the main body. A life signal producing device is provided for signaling the end of the service life of the electrostatographic material. The life signal is produced in response to a cartridge replacement signal and a final cartridge signal. Alternatively, the life signal is produced in response to a final cartridge signal and either a signal indicating a predetermined number of rotations of the image-bearing member or a cartridge replacement signal, whichever is produced earlier. A toner removing blade is held at a non-operating position when a process unit is detached from the image-forming machine and positioned in a unit holding box. When a predetermined number of toner cartridges have been selectively loaded and detached into and from the developing device, loading of a new toner cartridge is prevented. When a cartridge has been loaded and detached into and from the main body of the developing device, loading of another toner cartridge of the same type is prevented.

Removable developing units for a copying machine and display for

Developer cartridge

Process unit for copying machine

An image-forming machine comprising a main body of the machine and an image bearing member disposed within the main body and adapted to form an image on an electrophotographic material disposed on the surface of the image bearing member. According to a first aspect, the main body of the image-forming machine includes a lower supporting frame and an upper supporting frame mounted on the lower supporting frame for free pivotable movement between an open position and a closed position, and a cover member mounted on the upper supporting frame, in which when the upper supporting frame is held at the open position, the cover member covers part of the image bearing member. According to a second aspect, an image-forming area and a non-image-forming area exist on the surface of the image bearing member, and when an image-forming step is over, the non-image-forming area is positioned at a transfer opening formed for image transfer. According to a third aspect, a transfer zone in which to transfer the image to a sheet material and a peeling zone in which to peel the sheet material from the image bearing member are kept in a predetermined relationship so as to ensure accurate peeling of the sheet material.

Image-forming machine

A device for use with an image forming apparatus having a photosensitive drum and a developing device and a cleaning device disposed around the photosensitive drum for conducting developer recovered in the cleaning device to the developing device includes a circulating passage provided between the developing device and the cleaning device so as to communicate the developing device with the cleaning device. A discharging device discharges developer recovered in the cleaning device to the circulating passage, and a conveyor is disposed in the circulating passage to convey developer in the circulating passage to the developing device, the conveyor and the circulating passage being constructed to provide a space between the conveyor and the circulating passage such that a portion of the developer is allowed to be temporarily retained in such space. A supply device is provided for supplying developer conveyed by the developer into the developing device.

Device for circulating developer

An image-forming machine comprising a main body of the machine and an image bearing member disposed within the main body and adapted to form an image on a electrophotographic material disposed of the surface of the image bearing member. According to a first aspect, the main body of the image-forming machine includes a lower supporting frame and an upper supporting frame mounted on the lower supporting frame for free pivotable movement between an open position and a closed position, and a cover member mounted on the upper supporting frame, in which when the upper supporting frame is held at the open position, the cover member covers part of the image bearing member. According to a second aspect, an image-forming area and a non-image-forming area exist on the surface of the image bearing member, and when an image-forming step is over, the non-image-forming are is positioned at a transfer opening formed for image transfer. According to a third aspect, a transfer zone in which to transfer the image to a sheet material and a peeling zone in which to peel the sheet material from the image bearing member are kept in a predetermined relationship so as to ensure accurate peeling of the sheet material.

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.

Device for detecting the life of an image forming process unit, opening

An image-forming machine comprising a main body of the machine and an image bearing member disposed within the main body and adapted to form an image on a electrophotographic material disposed on the surface of the image bearing member. According to a first aspect, the main body of the image-forming machine includes a lower supporting frame and an upper supporting frame mounted on the lower supporting frame for free pivotable movement between an open position and a closed position, and a cover member mounted on the upper supporting frame, in which when the upper supporting frame is held at the open position, the cover member covers part of the image bearing member. According to a second aspect, an image-forming area and a non-image-forming area exist on the surface of the image bearing member, and when an image-forming step is over, the non-image-forming area is positioned at a transfer opening formed for image transfer. According to a third aspect, a transfer zone in which to transfer the image to a sheet material and a peeling zone in which to peel the sheet material from the image bearing member are kept in a predetermined relationship so as to ensure accurate peeling of the sheet material.

Image-forming machine having a cover member for covering part of an

An image forming machine provided with an image bearing member having a photosensitive material on its surface, a developing device for developing a latent electrostatic image formed on the surface of the photosensitive material, a cleaning device for removing toner remaining on the surface of the photosensitive material, and toner feed means for feeding the toner recovered in the cleaning device to the developing device. According to one aspect, the machine is constructed such that the color of toner used in the developing device can be easily determined. According to a second aspect, the image bearing member, the developing device and the cleaning device are mounted on a detachable unit frame, and the unit frame is adapted to be mounted and detached by means of a simple structure. According to a third aspect, the machine is constructed such that the toner recovered in the cleaning device is mixed in a predetermined amount with fresh toner and then fed to a developing chamber in the developing device. According to a fourth aspect, the machine is constructed such that fresh toner is sealed in a toner recovery chamber in the cleaning device during machine production. According to a fifth aspect, the machine is constructed such that a toner cartridge is loaded into the toner recovery chamber of the cleaning device.

Growing community of inventors

Osaka, Japan

Junichi Takamatsu