Is-enthalpic control of a thermal printing head
First Claim
1. A thermal printing device having is-enthalpic control comprising:
- a thermal printing head energizable by a selective flow of electrical energy to generate images on a responsive imaging material;
a heat transfer area associated with said head and disposed to effect transfer of heat generated by said head to a fluid heat transfer medium;
controllable moving means for moving said medium at a controllable flow rate to flow across said area to remove therefrom heat generated by said head;
measuring means for measuring a flow rate of electrical energy to said head;
determining means for determining a flow rate of heat energy removed from said head by said medium that flows across said area; and
control means for controlling said moving means, in dependence upon said measured flow rate of electrical energy to said head, and said determined flow rate of heat energy removed from said head by said medium, to adjust said controllable flow rate of said medium so that a net energy in said head remains substantially constant.
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Accused Products
Abstract
Is-enthalpic temperature control of the operation of the thermal printing head of a thermal printing device is attained by use of a transfer area at the head to transfer heat from the head to a coolant fluid moved by a fluid mover across the transfer area at a flow rate controlled by a circuit on the basis of a sensor that measures the flow rate of electrical energy being fed to the head, and sensors that sense the mass flow rate of the fluid and its rise in temperature upon flow across the transfer area for determining the flow rate of energy being removed from the head. The circuit controls the fluid mover to adjust the fluid flow rate so that the net energy in the head remains substantially constant.
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Citations
19 Claims
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1. A thermal printing device having is-enthalpic control comprising:
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a thermal printing head energizable by a selective flow of electrical energy to generate images on a responsive imaging material; a heat transfer area associated with said head and disposed to effect transfer of heat generated by said head to a fluid heat transfer medium; controllable moving means for moving said medium at a controllable flow rate to flow across said area to remove therefrom heat generated by said head; measuring means for measuring a flow rate of electrical energy to said head; determining means for determining a flow rate of heat energy removed from said head by said medium that flows across said area; and control means for controlling said moving means, in dependence upon said measured flow rate of electrical energy to said head, and said determined flow rate of heat energy removed from said head by said medium, to adjust said controllable flow rate of said medium so that a net energy in said head remains substantially constant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating a thermal printing device, having a thermal printing head, under is-enthalpic control, the method comprising the steps of:
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delivering a selective flow of electrical energy to the thermal printing head of the device to generate images on a responsive imaging material, said head being provided with a heat transfer area associated therewith to effect transfer of heat generated by said head to a fluid heat transfer medium; moving a flow of said medium across said area to remove therefrom heat generated by said head; measuring a flow rate of electrical energy to said head; determining a flow rate of heat energy removed from said head by said medium; and controlling said moving of said flow of said medium, in dependence upon said measured flow rate of electrical energy to said head and said determined flow rate of heat energy removed from said head by said medium, to adjust said flow of said medium so that a net energy in said head remains substantially constant. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification