Volume detecting device

Claim 2

A volume detector for detecting the volume of a powdery material in a container, which comprises: a first means for generating a periodic wavy motion of said powdery material so as to cause at least a portion of said powdery material to rise above and fall below a predetermined level; a level sensor disposed adjacent said powdery material undergoing said wavy motion for generating first and second signals, respectively, when at least a portion of said powdery material rises above and falls below said predetermined level; and a second means for measuring the time period during which either of said first and second signals are generated within a predetermined time period during the operation of said first means so as to detect the volume of said powdery material on the basis of said measured time period.

Claim 3

A volume detector as claimed in claim 1, wherein said second means comprises an integrator for integrating said either of said first and second signals for a predetermined period of time.

Claim 4

A volume detector as claimed in claim 1, further comprising a third means for generating a reference time period and comparing means for comparing said measured time period of said second means with said reference time period, wherein said comparing means produces a third signal when said measured time period overlaps said reference time period.

Claim 5

A volume detector as claimed in claim 3, wherein said third means comprises a variable means for changing said reference time period.

Claim 6

A volume detector as claimed in claim 1, wherein said level sensor is a pressure sensor.

Claim 7

A volume detector as claimed in claim 1, wherein said powdery material contains magnetic material, and wherein said level sensor is a magnetic sensor.

Claim 8

In a developing device having a developing tank containing a two-component type powdery developer mixture of toner and carrier particles, a toner dispensing device for dispensing toner powder into said developing tank to replenish the consumed toner, and a controller for detecting the concentration of said toner in said developer mixture in said developing tank so as to control the operation of a dispensing device on the basis of said detected concentration, said controller comprising: a first means for generating a periodic wavy motion of said developer mixture so as to cause at least a portion of said developer mixture to rise above and fall below a predetermined level; a level sensor disposed adjacent said powdery material undergoing said wavy motion for generating first and second signals, respectively, when at least a portion of said developer mixture rises above and falls below said predetermined level; a second means for measuring the time period during which said first signal is generated within a predetermined time period during the operation of said first means; a third means for generating a reference time period; a comparing means for comparing said measured time period from said second means with said reference time period, and for producing a third signal when said measured time period is shorter than said reference time period, said third signal being applied to said toner dispensing device for effecting the dispensing of toner powder into said developing tank so as to maintain the concentration of toner in said developer mixture constant.

Claim 9

In a developing device having a developing tank containing a two-component type powdery developer mixture of toner and carrier particles, a toner dispensing device for dispensing toner powder into said developing tank to replenish the consumed toner, and a controller for detecting the concentration of said toner in said developer mixture in said developing tank so as to control the operation of a dispensing device on the basis of said detected concentration, said controller comprising: a first means for generating a periodic wavy motion of said developer mixture so as to cause at least a portion of said developer mixture to rise above and fall below a predetermined level; a level sensor disposed adjacent said powdery material undergoing said wavy motion for generating first and second signals, respectively, when at least a portion of said developer mixture rises above and falls below said predetermined level; a second means for measuring the time period during which said first signal is generated within a predetermined time period during the operation of said first means; a third means for generating a reference time period; a comparing means for comparing said measured time period from said second means with said reference time period, and for producing a third signal when said measured time period is shorter than said reference time period, said third signal being applied to said toner dispensing device for effecting the dispensing of toner powder into said developing tank so as to maintain the concentration of toner in said developer mixture constant.

Claim 10

A volume detector as claimed in claim 7, wherein said first means comprises a rotatable roller provided in said developing tank so as to rotate at a constant speed such that a circumferential face of said roller move past different levels in said developing tank, and having at least one fin mounted on said roller.

Claim 11

A volume detector as claimed in claim 7, wherein said third means comprises a variable means for changing said reference time period.

Claim 12

A volume detector as claimed in claim 7, wherein said periodic wavy motion generated by said first means is a sinusoidal wave motion.

Claim 13

In a developing device having a developing tank containing a two-component type powdery developer mixture of toner and carrier particles, a toner dispensing device for dispensing toner powder into said developing tank to replenish the consumed toner, and a controller for detecting the concentration of said toner in said developer mixture in said developing tank so as to control the operation of a dispensing device on the basis of said detected concentration, said controller comprising: a first means for generating a periodic wavy motion of said developer mixture so as to cause at least a portion of said developer mixture to rise above and fall below a predetermined level; a level sensor disposed adjacent said powdery material undergoing said wavy motion for generating first and second signals, respectively, when at least a portion of said developer mixture rises above and falls below said predetermined level; a second means for measuring the time period during which said second signal is generated within a predetermined time period during the operation of said first means; a third means for generating a reference time period; and comparing means for comparing said measured time period from said second means with said reference time period, and for producing a third signal when said measured time period is longer than said reference time period, said third signal being applied to said toner dispensing device for effecting the dispensing of toner powder into said developing tank so as to maintain the concentration of toner in said developer mixture constant.

Claim 14

In a developing device having a developing tank containing a two-component type powdery developer mixture of toner and carrier particles, a toner dispensing device for dispensing toner powder into said developing tank to replenish the consumed toner, and a controller for detecting the concentration of said toner in said developer mixture in said developing tank so as to control the operation of a dispensing device on the basis of said detected concentration, said controller comprising: a first means for generating a periodic wavy motion of said developer mixture so as to cause at least a portion of said developer mixture to rise above and fall below a predetermined level; a level sensor disposed adjacent said powdery material undergoing said wavy motion for generating first and second signals, respectively, when at least a portion of said developer mixture rises above and falls below said predetermined level; a second means for measuring the time period during which said second signal is generated within a predetermined time period during the operation of said first means; a third means for generating a reference time period; and comparing means for comparing said measured time period from said second means with said reference time period, and for producing a third signal when said measured time period is longer than said reference time period, said third signal being applied to said toner dispensing device for effecting the dispensing of toner powder into said developing tank so as to maintain the concentration of toner in said developer mixture constant.

Claim 17

A volume detector as claimed in claim 11, wherein said first means comprises a rotatable roller provided in said developing tank so as to rotate at a constant speed such that a circumferential face of said roller moves past different levels in said developing tank, and having at least one fin mounted on said roller.

Claim 18

A volume detector as claimed in claim 11, wherein said third means comprises a variable means for changing said reference time period.

Claim 19

A volume detector as claimed in claim 11, wherein said periodic wavy motion generated by said first means is a sinusoidal wave motion.

Claim 20

A method as claimed in claim 12, wherein the step of measuring the time period of either the presence or absence of the sensed powdery material comprises integrating the time period during the sensed presence or absence of wavy powdery material at said predetermined level for a predetermined period of time.

Claim 21

A method as claimed in claim 12, further comprising the step of generating a reference time period and comparing the period of time during which the presence or absence of the wavy powdery material is at said predetermined level with the reference time period, wherein a signal is generated when the time period when the presence or absence of the wavy powdery material at said predetermined level is sensed overlaps the reference time period.

Claim 22

A method as claimed in claim 17, wherein the reference time period is variable.

Claim 23

A method as claimed in claim 12, wherein the step of sensing the presence and absence of wavy powdery material at said predetermined level comprises sensing the pressure at said predetermined level.

Claim 24

A method as claimed in claim 12, wherein said powdery material contains magnetic material and wherein the step of sensing the presence and absence of wavy material level at said predetermined level comprises magnetically sensing the presence and absence of wavy powdery material.