Abstract: An image-forming apparatus has: a transfer belt transferring a sheet; an encoder outputting a pulse signal in response to a rotational motion of the transfer belt; a belt reference sensor detecting a belt reference mark provided on the transfer belt; a first accumulator measuring a rotational position of the transfer belt against the reference mark by counting a pulse signal; a storage unit storing a table of printing timing correction values for one rotational cycle of the transfer belt; a second accumulator generating a printing timing signal by shifting a phase of the pulse signal by a printing timing correction value read from the table; and a image-forming unit controlling ink heads to eject inks on the sheet in synchronization with the printing timing signal, wherein an error in transfer amount of the sheet is calculated from a fluctuation in an interval of the inks ejected from the ink heads.

Abstract: An image-forming apparatus has: a transfer belt transferring a sheet; an encoder outputting a pulse signal in response to a rotational motion of the transfer belt; a belt reference sensor detecting a belt reference mark provided on the transfer belt; a first accumulator measuring a rotational position of the transfer belt against the reference mark by counting a pulse signal; a storage unit storing a table of printing timing correction values for one rotational cycle of the transfer belt; a second accumulator generating a printing timing signal by shifting a phase of the pulse signal by a printing timing correction value read from the table; and a image-forming unit controlling ink heads to eject inks on the sheet in synchronization with the printing timing signal, wherein an error in transfer amount of the sheet is calculated from a fluctuation in an interval of the inks ejected from the ink heads.

Abstract: An image-forming apparatus has: a transfer belt transferring a sheet; an encoder outputting a pulse signal in response to a rotational motion of the transfer belt; a bell reference sensor detecting a belt reference mark provided on the transfer belt; a first accumulator measuring a rotational position of the transfer belt against the reference mark by counting a pulse signal; a storage unit storing a table of printing timing correction values for one rotational cycle of the transfer belt; a second accumulator generating a printing timing signal by shifting a phase of the pulse signal by a printing timing correction value read from the table; and a image-forming unit controlling ink heads to eject inks on the sheet in synchronization with the printing timing signal, wherein an error in transfer amount of the sheet is calculated from a fluctuation in an interval of the inks ejected from the ink heads.

Abstract: A heat-sensitive stencil master making system includes a thermal head having an array of a number of heater elements which extends in a main scanning direction substantially perpendicular to a sub-scanning direction in which the thermal head is moved relatively to heat-sensitive stencil master material when imagewise perforating the heat-sensitive stencil master material. Each of the heater elements is longer in the main scanning direction than in the sub-scanning direction.

Abstract: A thermal head includes a heat radiating plate and an electrical insulating substrate which is provided with a plurality of resistance heater elements arranged in a direction over a predetermined length and a plurality of electrodes for energizing the resistance heater and is integrated with the heat radiating plate. The substrate is smaller than the heat radiating plate in coefficient of thermal expansion and is fixed to the heat radiating plate at a temperature higher than the normal working temperature range of the thermal head. In the normal working temperature range of the thermal head, the thermal head is convex toward the resistance heater in a cross-section taken along a line parallel to the direction in which the resistance heater elements are arranged due to the difference in coefficient of thermal expansion between the heat radiating plate and the substrate.

Abstract: A heat-sensitive stencil master making apparatus for making a stencil master by imagewise perforating thermoplastic film of heat-sensitive stencil master material according to an image on an original includes a thermal head which has an array of a plurality of heater elements and is brought into thermal contact with the thermoplastic film. Heater elements selected from the array of the heater elements according to the image on the original are applied with an electric voltage so that perforations are formed in the parts of the thermoplastic film of the heat-sensitive stencil master material in contact with the selected heater elements.

Abstract: A thermal head includes a heat radiating plate and an electrical insulating substrate which is provided with a plurality of resistance heater elements arranged in a direction over a predetermined length and a plurality of electrodes for energizing the resistance heater and is integrated with the heat radiating plate. The substrate is smaller than the heat radiating plate in coefficient of thermal expansion and is fixed to the heat radiating plate at a temperature higher than the normal working temperature range of the thermal head. In the normal working temperature range of the thermal head, the thermal head is convex toward the resistance heater in a cross-section taken along a line parallel to the direction in which the resistance heater elements are arranged due to the difference in coefficient of thermal expansion between the heat radiating plate and the substrate.