JP3136320B2 - Photoresponse measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus that irradiates an object responsive to light with pulsed light and measures the light responsiveness in response to an operation command signal. .

[Related Art] Conventionally, when evaluating the characteristics of a photoreceptor used for electrophotography, for example, photoresponsiveness may be measured. This can be obtained by irradiating the charged photoconductor with pulsed light using a shutter or the like, and measuring the responsiveness, that is, the change over time of the surface potential of the photoconductor. FIG. 3 is a view schematically showing a conventional photoresponsiveness measuring device. In FIG.
Reference numeral 10 denotes a lamp house that incorporates a lamp and emits light, 11 denotes a condenser lens, 12 denotes an openable and closable shutter disposed on an optical path so as to block light, and 13 denotes a shutter 12 according to a measurement start command signal. A shutter driver that opens for a fixed time, 14 is an optical fiber that transmits light, 20 is an irradiation unit that irradiates the charged photoconductor 21 with light, 22 is a transparent probe for measuring the surface charge of the photoconductor 21, 23 Is a surface electrometer,
Numeral 24 denotes a transient memory which generates a clock in response to the operation command signal, digitizes the input monitor output of the surface voltmeter, and stores it. Note that one end 14a of the optical fiber 14 is disposed at a converging point of the condensing lens 11, and the other end 14b is disposed at a position where the photoconductor 21 in the irradiation section 21 is irradiated. X is a measurement start command signal, and Y is a shutter open / close signal. FIG. 4 is a diagram showing signal waveforms of various parts. 4A shows a waveform of the opening / closing signal Y of the shutter 12, and FIG.
FIG. 3C is a diagram showing an optical signal applied to the memory, and FIG. 3C is a diagram showing a signal waveform stored in the transient memory 24.

In order to measure the photoresponsiveness of the photoconductor, a precharged photoconductor 21 is arranged at a predetermined position of the irradiation unit 20 and the lamp house 10
After the lamp is turned on, a measurement start command signal is sent from a control circuit (not shown) by pressing a measurement start button (not shown). At this time, the light radiated from the lamp house 10 is condensed by the condensing lens 11, but its optical path is blocked by the shutter 12 which is normally closed. This command signal is a command signal for opening the shutter 12 and also an operation command signal for starting the writing operation of the transient memory 24. Upon receiving this command signal, the shutter driver 13 sends an opening / closing signal Y as shown in FIG. 4A to the normally closed shutter 12 to open the shutter 12 for a certain period of time. Then, the light condensed by the condensing lens 11 is condensed on one end 14a of the optical fiber 14, and the condensed light is emitted from the other end 14b of the optical fiber 14, and the transparent probe 2
The photosensitive member 21 charged through 2 is irradiated with light as shown in FIG. 4B. As a result, the surface potential of the photoconductor 21 gradually decreases. The surface potential meter 23 reads the change over time of the surface potential with the transparent probe 22 and sends out the monitor output to the transient memory 24. On the other hand, the transient memory 24 has a command signal for starting measurement,
When the operation command signal is received, the writing operation is started as shown in FIG. 4C, and the monitor output sent from the surface electrometer 23 is digitized and stored. The stored memory is read out by a read start command signal (not shown), and its output U is supplied to, for example, a data processing computer (not shown). The surface potential of the photoreceptor charged by such a series of operations can be measured over time, and its photoresponsiveness can be measured.

[Problems to be Solved by the Present Invention] However, in the conventional photoresponsive measurement device, the shutter 12 is opened and the photoreceptor 21 is irradiated with a predetermined light amount in response to the command signal for starting the measurement. 4 only t _o delayed time required for opening and closing of the shutter 12 as shown in Figure b delayed the start of irradiation of the photosensitive member 21. For this reason, as shown in FIG. 4C, there was a time delay in the optical response of the photoconductor 21 measured. In this case, there is no problem as long as the response speed of the photoconductor is relatively slow and the time delay for opening and closing the shutter 12 can be ignored, but when a mechanical shutter is used. This delay is about 1msec ~ 5
msec. Therefore, when measuring the characteristics of the photoreceptor having a high light response speed, the delay cannot be ignored.
As described above, in the conventional light responsiveness measuring device, since a time delay has occurred between the time when the measurement start command signal is received and the time when the photoconductor is actually irradiated with light, a time delay occurs. It is not possible to determine whether the delay of the phenomenon stored in the transient memory 24 is a delay in the response of the photoconductor itself or a time delay until the irradiation start time.
There is a drawback that the change over time of the surface potential of the photoconductor cannot be accurately measured.

The present invention has been conceived in order to eliminate the above-mentioned drawbacks, and corrects a time delay from when a measurement start command signal is transmitted to when a predetermined amount of light is irradiated on the photoreceptor. It is an object of the present invention to provide a light responsiveness measuring device capable of accurately measuring the light responsiveness after a light amount is irradiated on a photoreceptor.

Means for Solving the Problems The present invention irradiates an object responsive to light with pulsed light, and measures an optical response in response to an operation command signal. A branching optical fiber, a light receiving element for receiving the branched light, a pre-amplifier for amplifying a signal from the light receiving element, a comparator for sending an output signal when an output of the pre-amplifier exceeds a reference value, and the comparator A variable resistor for adjusting the reference value of
An AND gate that receives an output signal of the comparator and a command signal for starting measurement and outputs an operation command signal, and includes a measurement operation blocking unit that does not start the measurement operation until the light amount detected by the light receiving element exceeds a predetermined value. It is a photoresponsiveness measuring device provided.

[Operation] When the present invention irradiates an object responsive to light with the above configuration, the measuring operation preventing means detects the amount of light applied to the object, and when the amount of applied light exceeds a predetermined value, An operation command signal is transmitted. Then, the optical responsiveness of the object is measured according to the operation command signal.

[Embodiment] An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a schematic configuration diagram of a photoresponsiveness measuring apparatus according to one embodiment of the present invention. In FIG. 1, 1
Is a pre-amplifier that outputs a voltage level corresponding to the amount of light, and OP-AMP
And a resistance element R and the like. Reference numeral 3 denotes a comparator for sending out an output signal when the output of the pre-amplifier exceeds a certain value. Reference numeral 4 denotes a variable resistor for adjusting the reference value of the comparator 3. Reference numeral 5 denotes an AND gate. Reference numeral 15 denotes a two-branch optical fiber. The input end 15a is arranged at the converging point of the condenser lens 11, the one output end 15b is arranged at the irradiation part, and the other output end 15c is arranged at the position irradiating the light receiving element 1. ing. The lamp house 10, condenser lens 11, shutter 12, shutter driver 13, irradiation unit 20, charged photoreceptor 21, transparent probe 22, surface voltmeter 23, and transient memory 24 are the same as those shown in the conventional example. Therefore, the detailed description is omitted by attaching the same reference numerals. E is a DC power supply for setting the reference voltage of the comparator 3, U is a read signal of the transient memory 24, X is a command signal for starting measurement, Y is an opening / closing signal of the shutter 12, and Z is an operation command signal of the transient memory 24. is there. The measurement start command signal X and the operation command signal Z are relayed by the AND gate 5. FIG. 2 is a diagram showing signal waveforms of various parts. Second
In the figure, a shows a waveform of the shutter opening / closing signal Y, b shows a waveform of an optical signal emitted to the photoconductor 21 by opening and closing the shutter, and c shows a potential change of the photoconductor surface read by the surface electrometer 23. FIG. 4D is a diagram showing the output waveform of the pre-amplifier 2, FIG. 5E is a diagram showing the waveform of the operation command signal Z, and FIG. 5F is a diagram showing the signal waveform stored in the transient memory 24.

In order to measure the potential change on the surface of the photoconductor by irradiating the charged photoconductor with a predetermined amount of light, a precharged photoconductor 21 is disposed at a predetermined position of the irradiation unit 20 and the lamp of the lamp house 10 is turned on. Press the start button (not shown) for starting the measurement. Then, a measurement start command signal X is transmitted from a control circuit (not shown). At this point, the light emitted from the lamp house 10 is condensed by the condenser lens 11, but its optical path is blocked by the shutter 12, which is normally closed. The shutter driver 13 receives the command signal X
When the shutter 12 is closed, the shutter 12 is normally closed.
The shutter 12 is opened for a certain period of time. Then, the light condensed by the condenser lens 11 is condensed on the input end 15a of the optical fiber 15, and the condensed light is branched in two directions. One of them is emitted from the output end 15b of the optical fiber 15, and is applied to the charged photoconductor 21 via the transparent probe 22. The other is optical fiber
The light is radiated from the 15 output terminals 15c and irradiates the light receiving element 1.
The optical signal is irradiated to the photosensitive member 21 and the light receiving element 1, after certain delay by the response delay t _o the shutter 12 as shown in FIG. 2 b, a waveform which rises with some inclination. When the photoconductor 21 is irradiated with light, the surface potential of the photoconductor 22 gradually decreases. As shown in FIG. 2C, the surface potential meter 23 reads the change over time in the surface potential with the transparent probe 22 and sends the monitor output to the transient memory 24. On the other hand, when the light emitted from the output end 15c of the optical fiber 15 irradiates the light receiving element 1, the light receiving element 1 converts this optical signal into an electric signal. Upon receiving this electric signal, the pre-amplifier 2 outputs a voltage level corresponding to the irradiation light amount, as shown in FIG. 2d. The comparator 3 receives this signal, compares it with a reference voltage value set in advance by the variable resistor 4, and sends out an output signal when the output voltage level of the pre-amplifier 2 exceeds this reference voltage value.
This output signal is input to the AND gate 4, and the AND gate 4 receives this output signal and the command signal X for starting measurement and outputs an output signal as shown in FIG. 2e. Upon receiving this output signal, that is, the operation command signal, the transient memory 24 starts a writing operation as shown in FIG. The stored memory is read out by a read start command signal (not shown), and its output U is supplied to, for example, a data processing computer (not shown).

As described above, according to the present embodiment, the transient memory 24 starts the writing operation when the predetermined irradiation light amount is irradiated on the photoconductor 21 and the photoconductor 21 read by the surface voltmeter 23.
The surface potential of the photoreceptor from the start of irradiation.
21 The potential change on the surface can be measured over time. Therefore, the optical response characteristics of the photoconductor 21 can be accurately measured.

Further, according to the present embodiment, the time delay from when the measurement start command signal is issued to when the predetermined amount of light is irradiated on the photoconductor 21 can be corrected. Pre-processing operation is not required.

In the above embodiment, the case where an optical fiber is used as a means for irradiating the light receiving element 1 with an optical signal has been described, but the irradiating means is not limited to this.
The light signal is reflected by other irradiation means, such as a mirror,
The reflected light may be applied to the light receiving element 1.

Further, in the above-described embodiment, the case where the irradiating unit 20 irradiates the surface of the photoconductor 21 by arranging the transparent probe 22 on the irradiation optical path and detects a change in the surface potential of the photoconductor 21 has been described. The method may be, for example, a method of irradiating light from the back surface of the photoconductor 21 and detecting a change in surface potential by the transparent probe 22 disposed on the opposite side.

Further, the present invention may be any device that irradiates an object responsive to light with pulsed light through a shutter, a flash lamp, or the like, and measures the light responsiveness in response to an operation command signal. However, the present invention is not limited to the method for measuring the change in the surface potential of the photoconductor as described above.

[Effects] As described above, according to the present invention, the measurement operation is not started until a predetermined amount of light is irradiated on an object that responds to light. It is possible to provide an optical responsiveness measuring device that can accurately measure over time from the start time and does not require a preprocessing operation when performing data processing.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an optical responsiveness measuring apparatus according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram of each part for explaining an embodiment of the present invention, and FIG. FIG. 4 is a schematic configuration diagram showing a responsiveness measuring device, and FIG. 4 is a signal waveform diagram of each section for explaining a conventional example. DESCRIPTION OF SYMBOLS 1 ... Light receiving element, 2 ... Preamplifier, 3 ... Comparator, 4 ... Variable resistor, 5 ... AND gate, 10 ... Lamp house, 11 ... Condensing lens, 12 ... Shutter, 13 ...
… Shutter driver, 15 …… Optical fiber, 20 ……
Irradiation unit, 21 photoreceptor, 22 transparent probe, 23 surface electrometer, 24 transient memory.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshinori Nozaki 3-7-14 Takada, Toshima-ku, Tokyo Inside Gentec Co., Ltd. (56) References JP-A-62-237344 (JP, A) JP-A Sho 55-76919 (JP, A) JP-A-2-135452 (JP, A) JP-A-55-32048 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 27/60 G03G 5/00-5/16 G01N 21/62-21/74 G01J 1/00-1/60

Claims (1)

(57) [Claims] An apparatus for irradiating an object responsive to light with pulsed light and measuring its light responsiveness in response to an operation command signal, comprising: an optical fiber for branching a part of the irradiated light; A light receiving element for receiving light, a pre-amplifier for amplifying a signal from the light receiving element, a comparator for transmitting an output signal when an output of the pre-amplifier exceeds a reference value, and a variable resistor for adjusting the reference value of the comparator Vessels,
An AND gate that receives an output signal of the comparator and a command signal for starting measurement and outputs an operation command signal, and includes a measurement operation blocking unit that does not start the measurement operation until the light amount detected by the light receiving element exceeds a predetermined value. A light responsiveness measuring device provided.