Abstract: A fixing belt includes a polyimide layer. The polyimide layer includes polyimide and an aprotic solvent. The solvent has a boiling point not lower than 230° C. and a solubility parameter not less than 24.5 (J/cm3)1/2 and not greater than 30.7 (J/cm3)1/2. The solvent has a content not less than 0.1 ppm and not greater than 1000 ppm in the polyimide layer.

Abstract: A fixing belt includes a polyimide layer. The polyimide layer includes polyimide and an aprotic solvent. The solvent has a boiling point not lower than 230° C. and a solubility parameter not less than 24.5 (J/cm3)1/2 and not greater than 30.7 (J/cm3)1/2. The solvent has a content not less than 0.1 ppm and not greater than 1000 ppm in the polyimide layer.

Abstract: A base for a fixing belt comprising at least: a nickel layer; and a copper layer, both laminated each other, wherein an orientation ratio I(200)/I(111) calculated based on a ratio between a peak strength of (200) crystal face and a peak strength of (111) crystal face by X-ray diffraction analysis of the copper layer is 0.1 or less. The base for the fixing belt further includes a protective layer, disposed on a surface of the copper layer opposite a surface on which the nickel layer is laminated, and the protective layer is formed of nickel.

Abstract: A fixing belt substrate for an image forming apparatus is prepared by an electroforming process. The fixing belt substrate contains nickel of prescribed weight percent, phosphorus of from about 0.4 weight percent or more to about 0.7 weight percent or less, sulfur of from about 0.003 weight percent or more to about 0.02 weight percent or less, and carbon of from about 0.012 weight percent or more to about 0.03 weight percent or less.

Abstract: A base for a fixing belt comprising at least: a nickel layer; and a copper layer, both laminated each other, wherein an orientation ratio I(200)/I(111) calculated based on a ratio between a peak strength of (200) crystal face and a peak strength of (111) crystal face by X-ray diffraction analysis of the copper layer is 0.1 or less. The base for the fixing belt further includes a protective layer, disposed on a surface of the copper layer opposite a surface on which the nickel layer is laminated, and the protective layer is formed of nickel.

Abstract: A base for a fixing belt includes a nickel layer; and a copper layer, both laminated each other, wherein an orientation ratio calculated based on a ratio between a peak strength of crystal face and a peak strength of crystal face by X-ray diffraction analysis of the copper layer is 0.1 or less. The base for the fixing belt further includes a protective layer, disposed on a surface of the copper layer opposite a surface on which the nickel layer is laminated, and the protective layer is formed of nickel.

Abstract: A fixing belt substrate for an image forming apparatus is prepared by an electroforming process. The fixing belt substrate contains nickel of prescribed weight percent, phosphorus of from about 0.4 weight percent or more to about 0.7 weight percent or less, sulfur of from about 0.003 weight percent or more to about 0.02 weight percent or less, and carbon of from about 0.012 weight percent or more to about 0.03 weight percent or less.

Abstract: A base for a fixing belt comprising at least: a nickel layer; and a copper layer, both laminated each other, wherein an orientation ratio I(200)/I(111) calculated based on a ratio between a peak strength of (200) crystal face and a peak strength of (111) crystal face by X-ray diffraction analysis of the copper layer is 0.1 or less. The base for the fixing belt further includes a protective layer, disposed on a surface of the copper layer opposite a surface on which the nickel layer is laminated, and the protective layer is formed of nickel.

Abstract: An optical information recording medium including a ROM region in which pits are previously formed at a track pitch (P); and a RAM region including a groove which is to be exposed to laser light to form at least one of a pit and a mark therein and to record information to be reproduced, wherein the pits in the ROM region are wobbled in a radius direction of the recording medium, a wobbling inter-pit groove is formed along the wobbled pits, wherein the width (W) of the inter-pit groove is narrower than that of the groove in the RAM region. The ratio (W/P) of the width (W) of the inter-pit groove to the track pitch (P) is preferably from 0.2 to 0.4.

Abstract: A mark representing information of a multivalued level is recorded in each of cells arranged in a recording medium. Upon reproducing the multivalued level from a reproduction signal of the recording medium, the multivalued level of a present cell is judged by referring to a judged multivalued level of a preceding cell preceding the present cell or an ensuing cell ensuing the present cell, or by referring to the judged multivalued levels of both the preceding cell and the ensuing cell.

Abstract: An optical information recording medium having a ROM area in which pre-pits are arranged in a line in advance, wherein a groove having a depth smaller than a depth of the pre-pits is formed between the pre-pits, and the groove has a width at junction parts smaller than a width of a part of the groove other than the junction parts. Preferably the following relationships are satisfied: ½ Wg?Wpg<Wg; and Wpg<Wp, where Wp, Wpg and Wg represent a width of the pre-pit, the width of the groove at the junction parts, and the width of the other part of the groove other than the junction parts, respectively.

Abstract: A mark representing information of a multivalued level is recorded in each of cells arranged in a recording medium. Upon reproducing the multivalued level from a reproduction signal of the recording medium, the multivalued level of a present cell is judged by referring to a judged multivalued level of a preceding cell preceding the present cell or an ensuing cell ensuing the present cell, or by referring to the judged multivalued levels of both the preceding cell and the ensuing cell.

Abstract: An optical information recording medium having a ROM area in which pre-pits are arranged in a line in advance, wherein a groove having a depth smaller than a depth of the pre-pits is formed between the pre-pits, and the groove has a width at junction parts smaller than a width of a part of the groove other than the junction parts. Preferably the following relationships are satisfied: ½ Wg?Wpg<Wg; and Wpg<Wp, where Wp, Wpg and Wg represent a width of the pre-pit, the width of the groove at the junction parts, and the width of the other part of the groove other than the junction parts, respectively.

Abstract: An information recording medium includes a transparent substrate and a recording layer or a metal layer provided on the transparent substrate directly or via a ground layer. The information recording medium has a RAM area on which information is recorded, reproduced or erased, and a ROM area from which only reproduction is made, and an average thickness of the recording layer of said RAM area is larger than that of the recording layer or metal layer of the ROM area.

Abstract: A mark representing information of a multivalued level is recorded in each of cells arranged in a recording medium. Upon reproducing the multivalued level from a reproduction signal of the recording medium, the multivalued level of a present cell is judged by referring to a judged multivalued level of a preceding cell preceding the present cell or an ensuing cell ensuing the present cell, or by referring to the judged multivalued levels of both the preceding cell and the ensuing cell.

Abstract: An optical information recording medium having a ROM area in which pre-pits are arranged in a line in advance, wherein a groove having a depth smaller than a depth of the pre-pits is formed between the pre-pits, and the groove has a width at junction parts smaller than a width of a part of the groove other than the junction parts. Preferably the following relationships are satisfied: ½ Wg≦Wpg<Wg; and Wpg<Wp, where Wp, Wpg and Wg represent a width of the pre-pit, the width of the groove at the junction parts, and the width of the other part of the groove other than the junction parts, respectively.

Abstract: An optical information recording medium including a ROM region in which pits are previously formed at a track pitch (P); and a RAM region including a groove which is to be exposed to laser light to form at least one of a pit and a mark therein and to record information to be reproduced, wherein the pits in the ROM region are wobbled in a radius direction of the recording medium, a wobbling inter-pit groove is formed along the wobbled pits, wherein the width (W) of the inter-pit groove is narrower than that of the groove in the RAM region. The ratio (W/P) of the width (W) of the inter-pit groove to the track pitch (P) is preferably from 0.2 to 0.4.

Abstract: An information recording medium includes a transparent substrate and a recording layer or a metal layer provided on the transparent substrate directly or via a ground layer. The information recording medium has a RAM area on which information is recorded, reproduced or erased, and a ROM area from which only reproduction is made, and an average thickness of the recording layer of said RAM area is larger than that of the recording layer or metal layer of the ROM area.

Abstract: An information storage medium having both a read-only optical storage portion and a magnetic storage portion that can be written and read is provided. There is also disclosed a drive unit for use with this information storage medium. To control the optical head of this drive unit, a system controller and a CLV servomechanism are provided and form a control portion. When information is written or read to or from the magnetic storage portion, this control portion commands a disk-rotating mechanism to control the magnetic head of the drive unit based on information read from the optical storage portion of the medium. The magnetic storage portion can have either a single track or plural tracks. Interference between the optical head and the magnetic head can be avoided. The drive unit can adapt itself to the information storage medium having the optical storage portion of a large storage capacity and the magnetic storage portion that can be easily rewritten.

Abstract: An improper writing prevention circuit having a source voltage detection circuit which detects the value of a source voltage and generates a first control signal to be sent to a state selection terminal of a memory device, a reference register in which a predetermined reference data is stored in advance, a first writing test register to and from which data can be written and read for receiving data to be referred to through a data bus, a validity check circuit for writing test which determines consistency of the reference data with the data to be referred to and generates a second control signal on the basis of the above determination, and a state selection circuit which generates a state selection signal to be applied to the state selection terminal in accordance with the first and second control signals. Improper writing operation to the memory can be prevented by changing its state from an active state to a non-active state by the state selection signal.