JPH0833581B2 - Positioning mechanism for LED array measuring device - Google Patents

Description

The present invention relates to a positioning mechanism of an optical characteristic measuring device for an LED array used as a light source of an LED printer device.

[Prior Art] A printer head of an LED array includes an LED array in which a large number of minute light emitters are linearly arranged at high density and a SELFOC lens array which is opposed to the LED array with a certain distance. There is an optical system configured.

Next, the configuration of the LED printer device will be described with reference to FIG.

In FIG. 7, 1 is an LED array incorporated in the printer head, 71 is an electrostatic photosensitive drum, 72 is corona charge, 73 is toner, 74 is a tray, 75 is a toner transfer section, and 76 is a heat fixing section.

When the light of the LED array 1 is applied to the electrostatic photosensitive drum 71 charged by the corona charge 72, only the place where the light hits is discharged.

For the paper sent from the tray 74, the electrostatic photosensitive drum 71
The toner is transferred by the toner transfer unit 75 to the position corresponding to the charged portion of the toner, and the toner 73 is fixed on the paper by the heat fixing unit 76.

Next, the relationship between the LED array 1 of FIG. 7 and the electrostatic photosensitive drum 71 will be described with reference to FIG. In FIG. 8, 81 is a SELFOC lens array, and 82 and 83 are gap rollers. When irradiating the light beam of the LED array 1 onto the electrostatic photosensitive drum 71,
If the amount of light emitted from the LED array 1 varies, the emission wavelength is different, or the distance between the LED array 1 and the SELFOC lens array 81 varies, clear print quality cannot be obtained.

Therefore, it is necessary to measure the light quantity, the light beam diameter, and the light spectrum of each light beam emitted from the LED array 1 and inspect the variation.

The LED array 1 has a large number of light emitters (hereinafter referred to as dots).
However, for example, the dot spacing is 52.9 μm and they are arranged very precisely, and in order to measure various optical characteristics of each of these dots, various optical sensors suitable for each measurement purpose are extremely precise. It is necessary to perform proper alignment.

Next, a measurement alignment mechanism for the LED array 1 according to the conventional technique will be described with reference to FIG.

Reference numeral 14 in FIG. 9 indicates that the LED array 1 is an LED with respect to the Y moving table 3.
LED array positioning blocks 15A, 16A, and 17A are used to set the position of the dot array direction of array 1 (hereinafter referred to as X direction) and the direction orthogonal to the dot array direction (hereinafter referred to as Y direction). For pressing the LED array positioning block 14 to the spring, springs 15A, 16A, 17
One end of A is fixed to the support blocks 15 to 17, respectively.

Holes 3B, 3C, and 3D for attaching various optical sensors suitable for each measurement purpose are formed in the Y moving table 3, and the Y moving table 3 is controlled by the motor 3A and the motor control circuit 11. . The Y moving table 3 is attached to the X moving table 2 that moves linearly in the X direction, and the operation of the X moving table 2 is controlled by the motor 2A and the motor control circuit 12.

Position setting surface of LED array positioning block 14 91A / 92A
Is adjusted to a precise constant distance L91 / L92 with respect to the Y moving base 3, L91 is the origin coordinate of the X moving base 2, and L92 is the origin coordinate of the Y moving base 3. 3B to 3D are mounting holes for various optical sensors, and L93 and L94 are Y-direction distances between the centers of the mounting holes 3B to 3D.

[Problems to be Solved by the Invention] In the positioning mechanism shown in FIG. 9, the operation for fixing the LED array 1 to the measuring device is complicated, and the LED array 1
When dust is pressed against the LED array positioning block 14, an error will occur in positioning accuracy, and since the position is indirectly set from the outer shape of the LED array 1, the outer shape of the LED array 1 If there is a dimensional variation between the size and the arrangement position of each dot, there is a problem that the positioning accuracy cannot be obtained.

This invention focuses on the fact that the array accuracy of each dot of the LED array 1 is extremely high, and emits an arbitrary 1 dot to electrically detect the center position of the light beam, and to measure the LED which is an object to be measured. An object of the present invention is to provide a highly accurate positioning mechanism capable of directly setting a position with respect to a light emitter inside the array.

[Means for Solving the Problem] In order to achieve this object, in the present invention, the first motor 2A is used to move X parallel to the arrangement direction of the LED array 1.
The moving table 2 and the second motor attached to the X moving table 2
A Y moving table 3 that moves at a right angle to the arrangement direction of the LED array 1 by 3A, and a first slit plate 4 attached to the Y moving table 3 and having a first slit 4A formed at a right angle to the arrangement direction of the LED array 1. , The first light receiving element 6 for receiving the light amount of the LED array 1 that has passed through the first slit 4A, and the Y moving table 3
Mounted on the second parallel to the array direction of the LED array 1.
The second slit plate 5 in which the slit 5A of
Second light receiving element 7 that receives the amount of light of the LED array 1 that has passed through the slit 5A, a first switch 8A that switches output currents of the first light receiving element 6 and the second light receiving element 7, and a first switch 8A.
The amplifier 9 for amplifying the output current of the switch 8A, the peak detection circuit 10 for detecting the maximum value of the output voltage of the amplifier 9 and outputting the logic level "1", and the logic output of the peak detection circuit 10 are First motor control circuit 11 for controlling the motor 2A
And a second switch 8B which is connected to the second motor control circuit 12 for controlling the second motor 3A by switching, and when the output of the peak detection circuit 10 is at the logic level "1", the X moving table 2 Alternatively, the movement of the Y moving base 3 is stopped and the LED array 1
Set the measurement position for.

[Operation] Next, the configuration of the positioning mechanism of the LED array measuring apparatus according to the present invention will be described with reference to FIG. 1 in FIG. 1 is an LED
Array, 2 is an X carriage, 3 is a Y carriage, 2A and 3A are motors, 4 and 5 are slit plates attached to the Y carriage, 6
And 7 are light receiving elements attached to the Y moving table together with the slit plates 4 and 5, 8A and 8B are switches for changing the positioning direction of the LED array 1, 9 is an amplifier, 10 is a peak detection circuit, and 11 and 12 are motor control. Circuit.

Next, a top view of the Y moving table 3 portion in FIG. 1 will be described with reference to FIG.

The X moving table 2 moves forward and backward by the motor 2A and moves in parallel with the arrangement direction of the LED array 1. The Y moving table 3 is attached to the X moving table 2, moves forward and backward by a motor 3A, and moves at a right angle to the arrangement direction of the LED array 1. The slit plate 4 is
It is attached to the Y moving table 3 and a slit 4A is opened at a right angle to the arrangement direction of the LED array 1. The slit plate 5 is attached to the Y moving table 3 and slits 5A are formed in parallel with the arrangement direction of the LED array 1.

Next, an exploded perspective view of the LED array 1 portion of FIG. 1 is shown in FIG.
It will be described with reference to the drawings.

The light receiving element 6 receives the light amount of the LED array 1 that has passed through the slit 4A, and the light receiving element 7 receives the light amount of the LED array 1 that has passed through the slit 5A. Switch 8A is a light receiving element 6
The output current of the switch 7 is switched, and the amplifier 9 amplifies the output current of the switch 8A. The peak detection circuit 10 detects the maximum value of the output voltage of the amplifier 9 and outputs a logic level "1".

FIG. 3 shows the movement direction of the slit plates 4 and 5 with respect to the light beam emitted from one dot of the LED array 1 and the slit 4A.
FIG. 6 is a perspective view showing a positional relationship between the light receiving elements 6 and 7 that receive the amount of light that has passed through 5A, and a slit plate 4 and a slit plate 5.
Is an LED that is separated by a fixed distance on the line that connects the gap rollers 82 and 83 by the X moving table 2 and the Y moving table 3, respectively.
It moves in the X and Y directions with respect to the array 1.

The LED array 1 shown in FIG.
When moved in the direction, the amount of light passing through the slit 4A is converted into an electric current by the light receiving element 6, and is amplified as Vin in FIG. 5 or a voltage waveform having a normal distribution intensity spread as shown in 9A in FIG. The amount of light which is taken out to the output of 9 and passes through the center of the light beam 1A through the slit 4A is maximized and coincides with the peak of the voltage waveform.

The peak detection circuit 10 in FIG. 3 inputs the voltage waveform from the amplifier 9 and outputs a logic level “1” as shown in FIG. 5C or 10A in FIG. 3 when the peak of the waveform is passed. To do.

Next, the motor control circuit 11 shown in FIG.
When the logic level "1" is input, the rotation of the motor 2A is stopped, and the measurement positioning in the X direction with respect to the X moving base 2 is performed.

[Example] In the X section of Vin shown in FIG. 5, the output voltage waveform of the amplifier 9 obtained when the n-th dot of the LED array 1 of FIG. And is proportional to the amount of light passing through the slit 4A of the slit plate 4 shown in FIG.

Next, the Y section of Vin shown in FIG. 5 is the output waveform of the amplifier 9 obtained when the n-th dot of the LED array 1 of FIG. 1 is caused to emit light and the Y moving table 3 is moved. , Third
It is proportional to the amount of light passing through the slit 5A of the slit plate 5 shown in the figure.

FIG. 3 shows the positional relationship from the light emitted from the LED array 1 to the light beam 1A passing through the SELFOC lens array 81, passing through the slit 4A and being received by the light receiving element 6, and the light receiving element 6. The light amount detection current of is input to the amplifier 9 through the switch 8A, and the peak detection circuit 10 outputs the light beam 1A.
It is a perspective view showing until the center is detected.

The slit plates 4 and 5 shown in FIG. 3 are located at a position separated from the LED array 1 by a certain distance, for example, in the case of an LED array including the gap rollers 82 and 83, on the line that connects the gap rollers 82 and 83 in a straight line. The array 1 is moved in the X direction or the Y direction.

Next, the facing distance from the LED array 1 to the slit plates 4 and 5 will be described.

The facing distance between the LED array 1 and the slit plates 4 and 5 is a unique value determined by the conjugate focal length of the SELFOC lens array 81 attached to the LED array 1, and various optical characteristics for the light beam from the LED array 1 are measured. It is necessary to set the light receiving positions of the optical sensors to be set to this value. LE
The D array 1 is required to maintain the distance to the electrostatic photosensitive drum 71 at this peculiar value in a state of being incorporated in the printer device. Generally, a structure provided at both ends of the LED array 1 is used like the gap rollers 82 and 83 in FIG.

 Next, the embodiment shown in FIG. 1 will be described.

The slit plates 4 and 5 have a width of 10 μm and a length of 3 mm, and the slit plates 4 and 5 have the same size and shape.

The slit plates 4A and 5A are attached to the Y-moving table 3 so that the lengthwise directions thereof are as shown in FIG. The light receiving elements 6 and 7 are attached to the Y moving base 3 so as to overlap the slit plates 4 and 5 in the positional relationship shown in FIG. L1 in Fig. 2 is slit 4A
5A center distance, L2 is slit 5A and optical sensor mounting hole 3B
Distance between centers and L3 and L4 are mounting holes 3B, 3C and 3D for optical sensor
Is a value used to set the position in the Y direction for each optical sensor, where the position of the slit 5A is the original position in the Y direction and L1 to L4 are the moving distances with respect to the Y moving base.

The switches 8A and 8B are for switching the original position setting for the movable table 2 and the Y movable table 3, and in the embodiment, the switches 8A and 8B.
Is an interlocking switch. Motor control circuit 11.
12 receives the logic signal from the peak detection circuit 10 and stops the rotation of the motors 2A and 3A when the logic level "1" is input. In the embodiment, the motors 2A and 3A using the 5-phase stepping motor are driven by the pulse current from the motor control circuits 11 and 12 to rotate. X moving table 2 and Y moving table 3
The moving amount of is proportional to the number of output pulses from the motor control circuits 11 and 12. For example, the movement amount per pulse is 1 μm
Is.

Next, a circuit diagram of an embodiment of the peak detection circuit 10 will be described with reference to FIG.

The circuit diagram of FIG. 4 is a peak hold circuit, which outputs a logic level "1" when the peak of the input voltage waveform has passed.

Reference numeral 41 in FIG. 4 denotes an analog switch, which conducts when the measurement start signal a is at the logic level “0”, and the measurement start signal a is supplied with the LED array 1 from the LED array control circuit 13 in FIG.
A logic output signal is applied which causes the light to be emitted. 42 in Figure 4
46 is a diode, 43 is a capacitor for peak hold,
44 is an operational amplifier with a low input bias current FET input, 4
Reference numeral 5 is an operational amplifier, and 47 is a comparator, which outputs a logic level "1" when the input voltage Vin exceeds a peak.

Next, FIG. 5 is an operation waveform diagram when the position detection operation for the light beam 1A of the LED array 1 is performed by using the circuit of FIG. 4 as the peak detection circuit 10 of FIG. 1, and FIG. Vi
The operation waveforms of n, a, a, and u and the parts indicated by Vin, a, a, and u in FIG. 4 are shown in association with each other.

Next, the positioning accuracy by using the circuit of FIG. 4 as the peak detection circuit 10 of FIG. 1 will be described.

In FIG. 1, the amplitude of the output voltage taken out by the amplifier 9 when the LED array 1 is made to emit light and the moving table 2 or the moving table 3 is operated is a normal function with respect to the moving amount of the moving tables 2 and 3. Shows a strong intensity distribution and the voltage amplitude is P (x),
It can be expressed by approximating the following equation.

P (x) = exp [- (φ (x)) 2/2] ...... (1) Here, φ (x) is the beam width of the spread of the beam center of the light beam 1A. For example, the beam diameter generally referred to is P
The value of φ (x) that gives (x) = 0.136 is used.

In the embodiment, the voltage gain of the operational amplifier 45 shown in FIG.
When the forward voltage of the diodes 42 and 46 is 0.7V and the input voltage Vin drops about 2mV after the peak amplitude has passed, the comparator 47 outputs the logic level "1" and the peak of the input voltage Vin. The amplitude is more than 1V. That is, the peak voltage difference is 2m
It is a peak detection circuit that detects V and outputs a logic pulse, and outputs a logic level “1” when P (x) ≦ 0.998 in the equation (1). In the embodiment, the beam diameter of the light beam 1A from the LED array 1 is 50 μmφ to 200 μmφ.

Next, when the moving amount by the moving bases 2 and 3 from the center position of the light beam 1A when the logical output level of the comparator 47 in FIG. 1A beam diameter (13.6%) is 50μmφ ~ 200μmφ and P (x)
From ≦ 0.998, when the beam diameter is 50μm, it is about 0.8μm, 200
When the beam diameter is μmφ, it is about 3.2 μm.

Next, the flowchart of the positioning mechanism of FIG.
It will be described with reference to the drawings.

Steps in FIG. 6 are X for the LED array 1.
The operation sequence is until the origin coordinates of the moving base are set, and steps to are the operation sequence until the origin coordinates of the Y moving base 3 are set.

The order of steps 1 to 3 in FIG. 6 can be exchanged.

[Effect of the Invention] According to the present invention, the irradiation intensity of the emission beam from the LED array is measured through the slit, and the peak of the irradiation intensity is logically detected using the peak detection circuit to set the positioning mechanism of the measuring device. Therefore, extremely high positioning accuracy can be set quickly by a simple operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a positioning mechanism of an LED array light emission characteristic measuring device according to the present invention, FIG. 2 is a top view of a movable table 3 part of FIG. 1, and FIG. 3 is an exploded view of the LED array 1 part of FIG. FIG. 4 is a perspective view, FIG. 4 is a circuit diagram of an embodiment of the peak detection circuit 10 of FIG. 1, FIG. 5 is a waveform diagram of each part of FIG. 4, FIG. 6 is a flowchart of the positioning mechanism of FIG. FIG. 8 is a block diagram of the LED printer device, FIG. 8 is an explanatory diagram of the relationship between the LED array 1 and the electrostatic photosensitive drum 71 of FIG. 7, and FIG.
It is a block diagram of a positioning mechanism of the D array measuring device. 1 ... LED array, 2 ... X moving base, 2A / 3A ... motor, 3 ... Y moving base, 4.5 ... slit plate, 6.7 ...
… Light receiving element, 8A ・ 8B …… Switch, 9 …… Amplifier, 10…
… Peak detection circuit, 11 ・ 12 …… Motor control circuit, 13 ……
LED array control circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G01J 1/00 C 9309-2G G03G 15/04 111 (72) Inventor Mitsuhiro Morishita Kamata, Ota-ku, Tokyo 4-19-7 Ando Denki Co., Ltd. (72) Inventor Osamu Ito 4-19-7 Kamata, Ota-ku, Tokyo In Ando Denki Co., Ltd.

Claims (1)

[Claims] 1. An X moving base (2) which is moved by a first motor (2A) in parallel with the arrangement direction of the LED array (1), and a second motor (3A) attached to the X moving base (2). ) Is mounted on the Y moving table (3) and the Y moving table (3) which moves at right angles to the arrangement direction of the LED array (1), and the first slit (4A is formed at right angles to the arrangement direction of the LED array (1). ) Is opened first
Attached to the slit plate (4), the first light receiving element (6) that receives the light amount of the LED array (1) that has passed through the first slit (4A), and the Y moving table (3), The second slit (5A) is formed in parallel with the arrangement direction of (1).
Slit plate (5), a second light receiving element (7) for receiving the light amount of the LED array (1) that has passed through the second slit (5A), a first light receiving element (6) and a second light receiving element (6). The first switch (8A) that switches the output current of the light receiving element (7), the amplifier (9) that amplifies the output current of the first switch (8A), and the maximum output voltage of the amplifier (9) is detected. The peak detection circuit (10) that outputs a logical level "1" and the logical output of the peak detection circuit (10) to the first motor (2A).
The first motor control circuit (11) for controlling the motor and the second switch (8B) for switching and connecting to the second motor control circuit (12) for controlling the second motor (3A), and the peak detection When the output of the circuit (10) is a logic level "1", the movement of the X moving table (2) or the Y moving table (3) is stopped and the measurement position for the LED array (1) is set. LED array measuring device positioning mechanism.