A toner suitable for use in an image forming method including a contact charging step is provided. The toner includes: toner particles comprising at least a binder resin and a colorant, and fine particles. The fine particles comprise: (i) a tungsten-containing tin oxide, or (ii) base particles, and a tungsten-containing tin compound coating the base particles, the fine particles contain tin (Sn) in a weight ratio (Sn/b) of 0.01 to 2.0 with respect to the base particles (B). In the fine particles, tungsten (W) is contained in a mol ratio (W/Sn) of 0.001 to 0.3 with respect to the tin (Sn).

Toner and image forming method

A magenta toner for developing an electrostatic image is formed of magenta toner particles containing at least a binder resin and a magenta pigment. The magenta pigment is a solid solution pigment comprising C.I. Pigment Red 122, C.I. Pigment Red 202 and C.I. Pigment Violet 19. The magenta toner particles are preferably formed by suspension polymerization of a polymerizable monomer mixture including a polymerizable monomer and the solid solution pigment in an aqueous medium.

Magenta toner for developing electrostatic images and process for production thereof

A medical imaging device 10 comprises an inverter 12 with semiconductor switches 26 for generating an AC voltage to be supplied to a load20, 22, a coil 32 inductively coupled to a conductor 34 of the inverter 12 connected with a semiconductor switch 26 of the inverter 12, and a monitoring circuit 60 for monitoring a current in the conductor 34 with a signal from the coil 32.

Medical imaging device

PROBLEM TO BE SOLVED: To provide an auxiliary power supply circuit of a switching power supply where a stable voltage is accurately supplied to a control circuit in using electronic parts without margin in a breakdown voltage for the control circuit and power loss is reduced for improving efficiency. SOLUTION: A series circuit consisting of a first resistor R1, a voltage element 2, and a zener diode Zd; and a series circuit consisting of a second resistor R2, a first transistor Q1, a second transistor Q2, and a control circuit 3 of a switching element; are connected in parallel with a main power supply 1. The input terminal of the first transistor Q1 is connected to the connection point between the first resistor R1 and the voltage element 2, the input terminal of the second transistor Q2 is connected to the connection point between the voltage element 2 and the zener diode Zd, and an auxiliary power supply 41 for steadily operating the control circuit 3 is connected between the connection point between the first transistor Q1 and the second transistor Q2 and the reference terminal of the main power supply 1.

Switching power supply

A switching power supply apparatus includes a transformer or an inductor, a switching element connected to the transformer or the inductor and configured to perform switching of an input power supply, and a switching control circuit including a digital control circuit configured to sample voltage values and/or current values and control on and off of the switching element in accordance with the voltage values and/or current values. The number of points of sampling is set to n or more points, where n is an integer greater than 3, in an ON period of the switching element except at around a turn-on point or a turn-off point of the switching element. The presence or absence of magnetic saturation of the transformer or the inductor is detected on the basis of whether or not a slope of change in current value over time is larger than a predetermined value, and circuit operation is protected from the effect of magnetic saturation. Thus, the presence or absence of magnetic saturation can be rapidly and precisely detected without the influence of switching noise.

Switching power supply digital control circuit protecting from magnetic saturation effects

PURPOSE:To prevent a small-sized and lightweight welding transformer from being damaged by detecting the magnetic saturation based on the variation of a primary current of the welding transformer to control a switching action of an inverter according to a detected signal. CONSTITUTION:In order to detect the magnetic saturation of the welding transformer 20, a current sensor 38 is provided to wiring between a primary coil of the welding transformer 20 and an output terminal of an inverter circuit 18. Then, an output signal of said current sensor 38 is supplied to a primary current detection circuit 40 which supplies an output signal SI corresponding to the primary current Ip to a magnetic saturation detection circuit 42. The magnetic saturation detection circuit 42 produces a detected signal MS indicating a magnetic saturated state of the welding transformer 20 and in response to said signal MS, a pulse width control circuit 32 controls the switching action of the inverter circuit 18 so as to regulate the pulse width of the primary current Ip when the magnetic saturation is generated.

Takashi Suzuki

Papers

Power source controller for inverter type resistance welding machine