Abstract:
A fluid dynamic bearing is constructed to support stably a rotating body to which a non-uniform force is applied, and a hard disk drive (HDD) employing the fluid dynamic bearing is provided. The fluid dynamic bearing includes a journal bearing part supporting a rotary shaft in a radial direction of the rotary shaft, a thrust part formed at one end of the rotary shaft, a thrust bearing part facing the thrust part and supporting the rotary shaft in a longitudinal direction of the rotary shaft, and a plurality of grooves formed on a surface of the thrust bearing part and/or the thrust part. The plurality of grooves include a first groove group including a plurality of grooves having the same shape and arrangement, and a second groove group adjacent to the first groove group and including at least one groove asymmetric with respect to the grooves of the first groove group.
Abstract:
An unlatch method through the change of a target track and an apparatus therefor are provided to enhance a successful rate of unlatch and prevent the failure of the entire unlatch caused by the defect of servo write and servo copy. A memory(200) stores unlatch target track information for unlatch. An unlatch executing unit(210) controls an HDA(Head Disc Assembly)(220), moves a head of a latch state to an unlatch target track stored in the memory(200), and attempts to execute the unlatch. If a servo signal read error is generated in the unlatch target track, a track changing unit(230) changes the unlatch target track to certain another track, stores changed unlatch target track information in the memory(200), and transmits the changed unlatch target track information to the unlatch executing unit(210).
Abstract:
A hard disc drive, a method for parking a magnetic head of the hard disc drive, and a recording medium storing a program for performing the method are provided to prevent a magnetic head from being damaged due to impact applied to the magnetic head through supply of an excessive parking current. It is determined whether a speed of a magnetic head is zero when the magnetic head is parked in a parking zone of a disc by driving of a VCM(Voice Coil Motor), to which a parking signal is applied(S19). If the speed of the magnetic head is zero, it is checked whether the magnetic head is normally parked in the parking zone(S20). The checking work is performed by compulsorily supplying a parking current of a predetermined value to the VCM.
Abstract:
PURPOSE: A printing plate cleaning device and a printing device including the same are provided to reduce the entire processing time by simplifying the entire printing process including a cleaning process and to minimize a volume of the entire printing device. CONSTITUTION: A printing plate cleaning device (100) includes a cleaning chamber (110), a nozzle support (160), and a complex nozzle unit. A printing plate (C) to be cleaned is arranged inside the cleaning chamber. The nozzle support is arranged inside the cleaning chamber. The complex nozzle unit is fixed to the nozzle support and includes a cleaning nozzle unit (140) and a rinsing nozzle unit (150) which are integrated. The cleaning nozzle unit includes a cleaning solution nozzle (143) injecting cleaning solution to the printing plate; and first suction nozzles (141, 144) sucking waste materials. The rinsing nozzle unit includes a rinsing solution nozzle (153) injecting rinsing solution to the printing plate; and second suction nozzles (151, 154) sucking waste materials.
Abstract:
PURPOSE: A roll-to-roll printing system is provided to transfer a flexible substrate with fluid running down after a process, in which the fluid of low viscosity such as a liquid crystal is utilized, by using a torque value of a nib roll driving motor. CONSTITUTION: A roll-to-roll printing system comprises a driven roll(130B), a pair of nib rolls(140B), a nib roll driving motor(142B), and a control device. The driven roll transmits power to a flexible substrate so that flexible substrate is transferred from an unwinding device to a rewinding device. The nib roll is mounted on both end portions of the driven roll, thereby pressurizing both end portions of the flexible substrate. The nib roll driving motor is connected to the nip roll in order to rotate-drive the nib roll. The control device receives the information of changes in a torque value of the nib roll driving motor. The tension of the flexible substrate is controlled by using the information.
Abstract:
A method and an apparatus for servo control under seek retry conditions and a disc drive using the same are provided to make a head stably be floating on a disc instead of parking if a condition that track seek or track following is normally not performed occurs. It is determined whether a seek retry condition occurs(S501). A servo control process is stopped and the value of back EMF(electromotive force) is detected if the seek retry condition occurs(S503). The speed of the voice coil motor is calculated by dividing the value of the back EMF by a back EMF constant(S504). Deceleration current to lower the speed of the voice coil motor to 0 is created so that the deceleration current is supplied to the voice coil motor(S505).
Abstract:
하드 디스크 드라이브, 하드 디스크 드라이브의 디펙트 검출 방법 및 그 방법을 수행하는 컴퓨터 프로그램을 기록한 기록 매체가 개시된다. 본 발명의 하드 디스크 드라이브의 디펙트 검출 방법은, (a) 적층된 다수개의 디스크의 각면에 대응되는 다수개의 자기 헤드 중 어느 하나가, 그에 대응되는 디스크의 디펙트를 스캔하되 온 트랙 스캔(On-track Scan) 및 오프 트랙 스캔(Off-track Scan)을 모두 실시하여, 디펙트가 검출된 디펙트 검출 실린더에 대한 정보를 저장하는 단계; 및 (b) 다수개의 자기 헤드 중 나머지 자기 헤드들이, 그에 각각 대응되는 디스크의 디펙트를 스캔하되 디펙트 검출 실린더에 대해서만 온 트랙 스캔(On-track Scan) 및 오프 트랙 스캔(Off-track Scan)을 모두 실시하여, 추가로 디펙트가 검출된 디펙트 검출 실린더에 대한 정보를 저장하는 단계를 포함하는 것을 특징으로 한다. 본 발명에 의하면, 디스크의 디펙트 검출시 신뢰성을 충분히 확보하면서도 디펙트 검출 공정 시간을 단축시켜 공정 효율을 향상시킬 수 있다. 하드 디스크, 디펙트, 스캔, 번인, 온 트랙 스캔, 오프 트랙 스캔