Abstract: In a calibration data input process, a carriage 5 is moved toward an ink sensor 19 to a prescribed position while the ink sensor 19 detecting levels of reflected light. Then the amount of reflected light is read for over a range wider than the width of the carriage 5 including a theoretical detecting position P2. An actual detecting position P1 is found based on the level of reflected light. The difference between the theoretical detecting position P2 and the actual detecting position P1 is calculated and is stored as the calibration value &agr; in a first calibration data memory M1. Accordingly, the actual detecting position P1 is set as P2 ±&agr;. The calibration value &agr; is used in a calibration process to calibrate the detecting position, so that the level of reflected light can be detected with accuracy.

Abstract: In a calibration data input process, a carriage 5 is moved toward an ink sensor 19 to a prescribed position while the ink sensor 19 detecting levels of reflected light. Then the amount of reflected light is read for over a range wider than the width of the carriage 5 including a theoretical detecting position P2. An actual detecting position P1 is found based on the level of reflected light. The difference between the theoretical detecting position P2 and the actual detecting position P1 is calculated and is stored as the calibration value &agr; in a first calibration data memory M1. Accordingly, the actual detecting position P1 is set as P2±&agr;. The calibration value &agr; is used in a calibration process to calibrate the detecting position, so that the level of reflected light can be detected with accuracy.

Abstract: The invention relates to an ink cartridge wherein a remaining amount of ink can be detected using an optical sensor. The ink cartridge has a window, for detection of an ink remaining amount, that is inclined at a predetermined angle with respect to the vertical direction. Inside of the ink cartridge, a preventive member is vertically provided. When the ink level is up to the window, light irradiated from the optical sensor permeates the window. Then, the light passes through the ink and reaches the preventive member. Preferably, the window is inclined approximately 20 degrees with respect to the preventive member. Accordingly, an incident angle of the light that has reached the preventive member is different from an incident angle of the light to the window. Thus, most of the light that has reached the preventive member is absorbed or is reflected by the preventive member in a direction different from the incident direction, so that the light reflected toward the optical sensor can be restricted.

Abstract: The invention relates to an ink cartridge wherein a remaining amount of ink can be detected using an optical sensor. The ink cartridge has a window, for detection of an ink remaining amount, that is inclined at a predetermined angle with respect to the vertical direction. Inside of the ink cartridge, a preventive member is vertically provided. When the ink level is up to the window, light irradiated from the optical sensor permeates the window. Then, the light passes through the ink and reaches the preventive member. Preferably, the window is inclined approximately 20 degrees with respect to the preventive member. Accordingly, an incident angle of the light that has reached the preventive member is different from an incident angle of the light to the window. Thus, most of the light that has reached the preventive member is absorbed or is reflected by the preventive member in a direction different from the incident direction, so that the light reflected toward the optical sensor can be restricted.

Abstract: To accurately position and fix an ink cartridge on an ink cartridge mounting unit, a first engaging depression is formed in the bottom wall of the ink cartridge and a corresponding protrusion is formed in the mounting unit. Also, an ink supply port is formed in the bottom wall. When the ink cartridge is mounted on the mounting unit, the ink supply port is engaged first with an ink supply channel formed in the mounting unit and fluidly connected to the head unit. Then, the first engaging depression is brought into engagement with the corresponding protrusion in the mounting unit. A second engaging depression is further formed in the top. The engaging pawl of a locking arm engages the second engaging depression when the locking arm locks the ink cartridge to the head unit. Further, a pair of ribs is provided on the rear side wall of the ink cartridge. The ribs oppose each other with a prescribed interval.

Abstract: In a calibration data input process, a carriage 5 is moved toward an ink sensor 19 to a prescribed position while the ink sensor 19 detecting levels of reflected light. Then the amount of reflected light is read for over a range wider than the width of the carriage 5 including a theoretical detecting position P2. An actual detecting position P1 is found based on the level of reflected light. The difference between the theoretical detecting position P2 and the actual detecting position P1 is calculated and is stored as the calibration value &agr; in a first calibration data memory M1. Accordingly, the actual detecting position P1 is set as P2±&agr;. The calibration value &agr; is used in a calibration process to calibrate the detecting position, so that the level of reflected light can be detected with accuracy.

Abstract: When the data supply rate from the data storing unit 11 drops and the amount of data remaining in the buffer memory 21 decreases, the calculation circuit 25 determines a data reproduction speed at which reproduction should be performed, dependently on the amount of data in the buffer memory 21. Accordingly, the video reading circuit 23 is controlled to retrieve video data from the buffer memory 21 at a reduced reproduction speed. The monitor 13 reproduces a slow motion pictures, which leads to an enhancement of the buffer memory.

Abstract: A microcomputer selects one of a plurality of drive units, and controls the selected drive unit to reproduce image data from a video disk located thereon. When a reproduction error occurs in the thus reproducing drive unit, the microcomputer selects another drive unit, and controls the drive unit to reproduce images. Accordingly, it is possible to always provide accurate images.

Abstract: An image recording apparatus which records an image of an original document on an image receiving sheet with the use of a photosensitive recording medium, the image receiving sheet having front and rear faces differing in reflection ratio. To detect error in sheet face orientation, a sheet face sensor unit is provided upstream of a pressure developing unit which discriminates a face of the image receiving sheet. The sensor unit includes a light emitting element for emitting light toward the face of the image receiving sheet and a light receiving element for receiving light emitted from the light emitting element and reflected on the face of the image receiving sheet.