Reading apparatus with improved clarity

Claim 2

A document-reading apparatus comprising: a photo-electric converter unit having a photo-electric diode, and a charge storing means connected in parallel to the photo-electric diode; a switch having one end connected to one end of the photo-electric converter unit; a DC power supply having one end connected to the other end of the switch, and directionally-coupled to supply a voltage in reverse bias across the photo-electric diode; and output means interposed between the other end of the photo-electric converter unit and the other end of the DC power supply for detecting a reading output signal to be supplied from the connecting point of the photo-electric converter unit and the output means; wherein the capacitance of said charge storing means is larger than the parasitic capacitance of said switch.

Claim 3

A document-reading apparatus comprising: (A) a plurality of groups (1 to n) of fundamental circuits, each of which comprises: (i) a plurality of fundamental circuits (1 to i) connected to each other in parallel, each fundamental circuit comprising: (a) a photo-electric converter unit having photo-electric diode D ni , and a charge storing means C ni connected in parallel to the photo-electric diode D ni , and (b) a switch S ni having one end connected to one end of the photo-electric converter unit, (ii) means A 1 to A n for supplying a reading output signal each having an input end commonly connected to the other end of photo-electric converter units, within the corresponding group n of fundamental circuits, and having an output end connected to supply a reading output signal, the output ends of the reading output signal supplying means A 1 to A n of the groups of fundamental circuits being connected commonly to each other; and (iii) impedance means R 1 to R n each having one end commonly connected to the other end of the photo-electric converter units within the corresponding group n of fundamental circuits for detecting the reading output signal supplied from the connecting point of the other end of each photo-electric converter unit; (B) A DC power supply having one end connected commonly to the other end of each switch S 11 to S ni and having the other end of the power supply connected commonly to the other end of each impedance means R 1 to R n , and directionally-coupled to supply a voltage in reverse across the photo-electric diodes D 11 to D ni ; and (C) means for scanning the switches S 11 to S ni to turn them on and off in a successive sequence of time; wherein the capacitance of said charge storing means is larger than the parasitic capacitance of said switch.

Claim 4

A document-reading apparatus comprising: (A) a plurality of groups (1 to n) of fundamental circuits, each of which comprises: (i) a plurality of fundamental circuits (1 to i) connected to each other in parallel, each fundamental circuit comprising: (a) a photo-electric converter unit having photo-electric diode D ni , and a charge storing means C ni connected in parallel to the photo-electric diode D ni , and (b) a switch S ni having one end connected to one end of the photo-electric converter unit, (ii) means A 1 to A n for supplying a reading output signal each having an input end commonly connected to the other end of photo-electric converter units, within the corresponding group n of fundamental circuits, and having an output end connected to supply a reading output signal, the output ends of the reading output signal supplying means A 1 to A n of the groups of fundamental circuits being connected commonly to each other; and (iii) impedance means R 1 to R n each having one end commonly connected to the other end of the photo-electric converter units within the corresponding group n of fundamental circuits for detecting the reading output signal supplied from the connecting point of the other end of each photo-electric converter unit; (B) A DC power supply having one end connected commonly to the other end of each switch S 11 to S ni and having the other end of the power supply connected commonly to the other end of each impedance means R 1 to R n , and directionally-coupled to supply a voltage in reverse across the photo-electric diodes D 11 to D ni ; and (C) means for scanning the switches S 11 to S ni to turn them on and off in a successive sequence of time; wherein the capacitance of said charge storing means is larger than the parasitic capacitance of said switch.

Claim 5

A document reading apparatus having a plurality of fundamental circuits for reducing output noise, each fundamental circuit comprising: a photo-electric converter unit having a photo-electric diode and means for storing electric charges, the photo-electric diode and charge storing means being coupled in parallel; a switch; a DC power supply; and an impedance means for providing load resistance; wherein the photo-electric converter unit, the switch, the DC power supply and the impedance means are coupled in series in that order in a loop, wherein the DC power supply applies a voltage in reverse bias across the photo-electric unit, wherein an output voltage signal is readable at a point between the impedance means and the photo-electric converter unit, and wherein the capacitance of said charge storing means is larger than the parasitic capacitance of said switch.

Claim 6

A document reading apparatus having a plurality of fundamental circuits for reducing output noise, each fundamental circuit comprising: a photo-electric converter unit having a photo-electric diode and means for storing electric charges, the photo-electric diode and charge storing means being coupled in parallel; a switch; a DC power supply; and an impedance means for providing load resistance; wherein the photo-electric converter unit, the switch, the DC power supply and the impedance means are coupled in series in that order in a loop, wherein the DC power supply applies a voltage in reverse bias across the photo-electric unit, wherein an output voltage signal is readable at a point between the impedance means and the photo-electric converter unit, and wherein the capacitance of said charge storing means is larger than the parasitic capacitance of said switch.

Claim 7

A reading apparatus as claimed in claim 3 wherein the ratio of capacitance C1 of said electric charge storing means to the parasitic capacitance SC of said switch is determined as follows: Cl/SC>1

Claim 8

A reading apparatus as claimed in claim 3 wherein the ratio of capacitance C1 of said electric charge storing means to parasitic capacitance SC of said switch is determined as follows: Cl/SC>3