JP2002236032A - Rotational position detector and image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable rotational information, by keeping any noises from being mixed into a pulse signal outputted from a rotary encoder, even if noises mix into the rotary encoder connected to a motor. SOLUTION: The rotary encoder is so arranged as to be separated into an RE optical unit 56 and an RE electrical unit 58. An optical signal is supplied to a rotating encoding plate 64 through an optical fiber cable 120 from a light source 124 for RE of the RE electrical unit 58, and the optical signal passing through the encoding plate 64 is supplied to a photodetecting part 122, having photodiodes 134 and 136 through the optical cable 120. With such an arrangement, electromagnetic noise will not mix into the RE electrical unit 58 from the RE optical unit 56, thereby enabling obtaining of an A-phase pulse, a B- phase pulse and a Z-phase pulse, as stable rotational position detection signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical rotary position detecting device (rotary encoder) and an image recording apparatus having the rotary position detecting device incorporated therein. The present invention relates to a rotational position detecting device that is designed to be strong and has a high SN ratio, and to an image recording device incorporating the rotational position detecting device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a drum 14 rotates a cylindrical drum 14 at a substantially constant speed.
The main scanning (in the direction of the arrow X) of the photosensitive material (sensitive material) 12 held on the outer peripheral surface 16 of the drum 14 is performed by the intensity-modulated light beam L emitted from the optical unit 34 having a laser diode or the like. Scanning) and moving the optical unit 34 along the axis 18 of the drum 14 to perform sub-scanning (scanning in the direction of arrow Y) to record a two-dimensional image on the entire surface of the photosensitive material 12. A light beam image recording device 10 is known (for example, see Japanese Patent Application Laid-Open No. 5-207250).

In this image recording apparatus 10, a rotation position detecting device (rotary encoder) 24 is attached to a shaft 18 of a drum 14 rotated by a drum motor 4.

The rotary encoder 24 has, for example, a Z-phase slit, an A-phase slit, and a B-phase slit in its circumferential direction.
It has an encoding plate in which a phase slit is formed, and the encoding plate is coaxially mounted on the shaft 18 of the drum 14.

In this case, a pair of a light-emitting element and a light-receiving element is arranged so as to sandwich each slit, and continuous light emitted from the light-emitting element is blocked by the slit formed in the rotating encoding plate. The light is incident on each light receiving element as an optical signal to be turned on / off.

A Z-phase pulse Pz (one pulse per rotation) and an A-phase pulse P as electric signals output from each light receiving element
a (for example, 5000 pulses per rotation) and a B-phase pulse Pb (a pulse shifted by 90 ° with respect to the A-phase pulse Pa) constitute a signal processing unit 28 through a signal line 15 as a PLL (Phase lock). loop) circuit 30
Supplied to

The PLL circuit 30 multiplies, for example, the A-phase pulse Pa by a predetermined number, generates a pixel clock CK corresponding to the resolution (recording resolution) of an image recorded on the photosensitive material 12, and supplies the pixel clock CK to the image memory 44. I do.

The image memory 44 outputs a binary (value 0 and value 1) image signal corresponding to the pixel clock CK and supplies it to a laser driver unit (LD driver unit) 46.

The laser driver unit 46 supplies an electric signal that turns on and off in response to an image signal to the laser diode that constitutes the optical unit 34, so that a light beam L that turns on and off is emitted from the laser diode.
Irradiation with respect to 2 forms a two-dimensional gradation image, for example, a halftone image, on the photosensitive material 12.

As described above, the light beam L which is turned on and off in synchronization with the pulses Pz, Pa, and Pb output from the rotary encoder 24 is supplied from the optical unit 34 to the photosensitive material 12, so that an image with high graphic accuracy can be sensed. It can be formed on the material 12.

[0011]

By the way, power is supplied to the rotary encoder 24 from a power supply unit 23 through a power supply line (ground line and voltage applying line) 25 which is an electric wire. The signal is supplied to the signal processing unit 28. Further, power is also supplied to the optical unit 34 and the laser driver unit 46 through the power lines 6 and 8 which are electric wires.

Thus, as a result, the power supply lines 25, 2
7 and the signal line 15 through the rotary encoder 2
4 and the signal processing unit 28 are electrically connected.

Here, in the image recording apparatus 10 shown in FIG. 4, for example, a printing plate for a printing original plate is adopted as the photosensitive material 12.

In the case of a printing plate, for example, the drum 14 has a diameter of about 300 [mm], a length of about 1 [m],
An aluminum product weighing more than 80 [kg] is used.

In order to stably rotate the drum 14 having such a weight at a constant speed, the drum motor 4
For example, with AC 200 [V], 2-3 directly driven
An AC servo motor on the order of [kW] is required.

However, when the drum motor 4 having a large output is used, noise generated by the drum motor 4 is generated by the power supply line 2 of the rotary encoder 24.
5 and the signal line 15 to the signal processing unit 28.

In that case, the PLL
The phase of the pixel clock CK output from the circuit 30 fluctuates with time, and as a result, the graphic accuracy of the image recorded on the printing plate 12 decreases. When the image is a halftone dot image, so-called shaking of the net occurs, and inconveniences such as generation of a curved line-like unevenness appear.

In recent years, it has been demanded that the drum 14 be driven at a high speed in order to improve productivity, and the noise generated by the drum motor 4 tends to be further increased.

Therefore, measures to avoid the generation of noise around the rotary encoder 24 are important issues for operating the image recording apparatus 10 stably and with high accuracy.

The present invention has been made in view of such a problem, and ensures stable rotation information (rotational position detection signal) even when the noise level (noise level) in an apparatus such as an image recording apparatus increases. It is an object of the present invention to provide a rotational position detecting device and an image recording device capable of obtaining a rotational position.

Further, according to the present invention, the rotational position detection signal S
It is an object of the present invention to provide a rotational position detecting device devised so as to increase the N ratio, and an image recording device incorporating the rotational position detecting device.

[0022]

According to the present invention, there is provided a rotational position detecting apparatus comprising: a rotatable encoding plate provided with a plurality of light intensity modulating portions in a circumferential direction; Light emitting means for emitting light to the light emitting means, light receiving means for receiving light emitted from the light emitting means and obtained through the light intensity modulation section, and light for supplying light to the light emitting means A supply optical fiber, and a light deriving optical fiber for deriving light received by the light receiving unit, and only an optical signal, not an electric signal, is input / output through the light supplying optical fiber and the light deriving optical fiber. (Invention of claim 1).

According to the present invention, since only the optical signal is input to and output from the rotation position detecting device, a stable rotation detection position signal can be obtained without electromagnetic noise. . In other words, the SN ratio of the rotational position detection signal becomes relatively high.

The light intensity modulating section can be, for example, a light transmitting section or a light reflecting section (the invention according to claim 2).

According to the present invention, there is provided a rotational position detecting apparatus comprising: an optical unit including only an optical system for detecting a rotational position of an encoding plate provided with a plurality of light intensity modulating units in a circumferential direction; Comprises an optical fiber cable optically connected to the optical fiber cable, and an electric unit optically connected to the other end of the optical fiber cable. A light source for irradiating an optical input signal to the intensity modulation section through the one end of the optical fiber cable, and the light output from the light intensity modulation section of the encoding plate and introduced through the other end of the optical fiber cable; An electric unit having a light receiving unit that converts an optical signal whose light intensity changes according to the rotational position of the encoding plate into an electric signal. To (invention described in claim 3).

According to the present invention, there is provided an optical unit comprising only an optical system including an encoding plate, and an electric unit optically connected to the encoding plate constituting the optical unit through an optical fiber cable. Since the electric unit is provided with a light source and a light receiving unit,
Electromagnetic noise does not enter the electric unit from the optical unit, and a stable rotational position detection signal can be obtained.

According to the image recording apparatus of the present invention, an image is recorded by scanning in a main scanning direction by an image recording means on a recording sheet held on an outer peripheral surface of a drum rotated by a rotary drive source. By moving the image recording means in a sub-scanning direction substantially orthogonal to the main scanning direction,
In an image recording apparatus that forms a two-dimensional image on the recording sheet, a rotation position detection device that detects a rotation position of a rotation shaft of the drum, and a rotation position detection signal that is detected by the rotation position detection device. A signal processing unit that reads an image signal from an image memory and supplies the read signal to the image recording unit, wherein the rotation position detection device is mounted and rotated so as to coincide with the axis of the drum, and outputs a plurality of light beams in a circumferential direction. An optical unit consisting only of an optical system for detecting the rotational position of the encoding plate provided with the intensity modulation section, an optical fiber cable having one end optically connected to the optical unit, and the other end of the optical fiber cable An electrical unit optically connected to the optical unit, wherein the optical fiber cable is connected to the light intensity modulating unit of the encoding plate constituting the optical unit. A light source for irradiating an optical input signal through the one end of the optical fiber cable, and a rotation position of the encode plate that is output from the light intensity modulation unit of the encode plate and is introduced through the other end of the optical fiber cable. A light receiving unit that converts an optical signal whose light intensity changes to an electrical signal, and supplies the electrical signal as the rotational position detection signal to the signal processing unit. Item 4).

According to the present invention, the light source and the light receiving unit are provided in the electric unit optically connected to the encoding plate constituting the optical unit through the optical fiber cable. On the other hand, a stable rotational position detection signal can be obtained without electromagnetic noise being mixed. As a result, noise does not mix with the image formed on the recording sheet, and the graphic accuracy of the image formed on the recording sheet is improved.

[0029]

An embodiment of the present invention will be described below with reference to the drawings. In the drawings referred to below, those corresponding to those shown in the example of FIG. 4 described above are given the same reference numerals or the same reference numerals with the suffix “A” appended.

FIG. 1 shows a schematic overall configuration of a light beam image recording apparatus 10A to which an embodiment of the present invention is applied.

The light beam image recording apparatus 10A has a drum 14 on which a printing plate (also referred to as a recording sheet) 12, which is a recording sheet for recording an image, is mounted. The printing plate 12 is wound around the outer peripheral surface 16 of the drum 14, and is closely held and fixed to the outer peripheral surface 16 by a holder (not shown).

In this embodiment, the drum 14
An aluminum cylinder having a diameter of 300 [mm] and a length of about 1 [m] is used. Weight is 80 [kg]
Is over.

The shaft 18 of the drum 14 has an AC drive source for rotating the drum 14 in the main scanning direction X at a constant speed.
A drum motor 20, which is a servomotor, is attached. The drum motor 20 is supplied with an AC voltage of 200 [V] from an AC power supply unit 52.

The shaft 22 on the opposite side of the drum motor 20
An optical unit (RE optical unit) that constitutes a rotary encoder 54 as a rotational position detecting device that is a main scanning direction recording position detecting unit that is driven to rotate together with the drum 14 is provided on (an axis coaxial with the axis 18 of the drum 14). ) 56
Is attached. The RE optical unit 56 has the axis 1
8 can also be mounted. RE optical unit 56
Can be attached to either the top side or the bottom side of the drum 14.

The rotary encoder 54 basically includes the RE optical unit 56, a RE electric unit 58 described later, and the RE optical unit 56 and the RE optical unit 56.
And an optical fiber cable 120 for optically connecting the electrical unit 58 to each other.

The ball screw 3 is arranged in parallel with the shaft 18 of the drum 14.
An optical unit 34 as an optical system serving as image recording means is mounted on the ball screw 32 and a rail (not shown). The optical unit 34 forms a laser diode 36 serving as a laser light emitting unit that generates a light beam L that is a laser beam, and forms an image of the light beam L emitted from the laser diode 36 and irradiates the printing plate 12 on the drum 14 with the image. And an image forming optical system 38.

At one end of the ball screw 32, a sub-scanning motor such as a stepping motor, which is a rotary driving source of the ball screw 32, for moving the optical unit 34 in the sub-scanning direction Y along the axis 18 of the drum 14 in parallel. 40 are attached.

Further, an origin detector 42 for detecting the origin of the optical unit 34 in the sub-scanning direction Y is fixedly disposed on one end side of the drum 14, and the origin detector 42 is provided in the sub-scanning direction of the optical unit 34. The Y origin detection signal is supplied to the mechanical control unit 26.

The mechanical control unit 26 rotates the drum motor 20 at a substantially constant speed based on an instruction from a host computer (not shown), an origin detection signal, and an A-phase pulse Pa and a Z-phase pulse Pz described later. The sub-scanning motor 40 is rotated by one step for each Z-phase pulse Pz, and the optical unit 34 is stepped in the sub-scanning direction Y.

FIG. 2 shows a schematic internal configuration of the RE optical unit 56.

The RE optical unit 56 has a rotating shaft 22
An encoding plate 64, which is a glass disk, which can be mounted in the same axial direction, and is provided with a plurality of light transmitting portions 60, 62 which are slits as light intensity modulating portions in the circumferential direction. A slit plate 78 provided so as to face a part of the encoding plate 64, and a projection plate for projecting light to the light transmitting portions 60 and 62 so as to sandwich the encoding plate 64 and the slit plate 78 therebetween. The light emitting device includes light projecting lenses 70, 72, and 74 as light means and light receiving lenses 90, 92 and 94 as light receiving means.

One of the light transmitting portions 60 formed on the circumference of the encoding plate 64 at the same angular interval (here, 5000) functions as an A-phase pulse and a B-phase pulse output. The other light transmitting portion 62 formed only one on the circumference functions as a Z-phase pulse output.

The RE optical unit 56 includes light supply optical fibers 100, 102, 104 for supplying light to the light projecting lenses 70, 72, 74, respectively, and light received by the light receiving lenses 90, 92, 94. Are provided, respectively.

In this case, the continuous lights La, Lz, Lb projected through the projection lenses 70, 72, 74 are:
The light transmitting portions 60, 62 of the rotating encoding plate 64,
Light signals Lam, Lzm, and Lbm, which are light intensity modulation signals, are transmitted through the A-phase slit 80, the Z-phase slit 84, and the B-phase slit 82 on the slit plate 78 disposed at a fixed position with respect to the encoder plate 64 and the encoder plate 64. .

The optical signals Lam, Lzm, and Lbm are condensed through light receiving lenses 90, 92, and 94, and are transmitted through the light guiding optical fibers 110, 112, and 114 facing the light receiving lenses 90, 92, and 94. Are output as the A-phase pulse Par, the Z-phase pulse Pzr, and the B-phase pulse Pbr.

[0046]

The A-phase pulse Par and the Z-phase pulse Pzr of the optical signal output from the RE optical unit 56 are shown in FIG.
As shown in the figure, the RE electric unit 58 constituting the signal processing unit 28A through the optical fiber cable 120.
The light is supplied to the light receiving unit 122 inside. In this embodiment, since the drum 14 is rotated in one direction only in the main scanning direction X, the B-phase pulse Pbr as an optical signal is
It is not led out of the RE optical unit 56 to the optical fiber cable 120.

The optical fiber cable 120 has a RE light source 124 constituting the RE electric unit 58.
, Continuous light La, Lb, and Lz (see FIG. 2) for projecting light are supplied to the RE optical unit 56 through the optical fiber cable 120.

The optical fiber cable 120 is connected to the optical fibers 100, 102, 104, 110, and 11 described above.
2, 114 are combined into one.

FIG. 3 shows a schematic mounting configuration of the rotary encoder 54. Rotary encoder 54
Are RE optical unit 56 and RE electric unit 58,
And an optical fiber cable 120 for optically connecting them.

In this case, on the substrate 130 of the signal processing unit 28A, a RE light source 124 composed of a laser diode for optical access communication of a DIL (Dual Inline Package) type and a modularized photo as a light receiving unit 122 are provided. Diodes 134 and 136 are mounted.

The RE light source 124 and the photodiodes 134 and 136 are connected to the RE through an optical fiber 138 with an optical connector and an optical fiber cable 120, respectively.
Optical fibers 100, 102, 11 in the optical unit 56
0 and 112 are optically connected.

Here, the signal processing unit 28A is housed in an electromagnetic shield case 140, and the electromagnetic shield case 140 is provided with a detachable optical connector 142.

On the other hand, the RE optical unit 56 is housed in a light-shielding case 146, and the light-shielding case 146 is provided with a detachable optical connector 144.

The axis 148 of the encoding plate 64 constituting the RE optical unit 56 is located at the light shielding case 146.
One end of the shaft 148 is supported by bearings 150 and 152, and one end of the shaft 148 is connected to the shaft 22 of the drum motor 20 through a joint 154.
Has been fixed.

Referring again to FIG. 1, the A-phase pulse Par and the Z-phase pulse Pzr of the optical signal supplied to the light receiving unit 122, which is a photoelectric conversion unit, are photoelectrically converted by the light receiving unit 122, and the A-phase pulse of the electric signal is output. It is converted into Pa and Z phase pulses Pz. The A-phase pulse Pa is supplied to the PLL circuit 30, and the A-phase pulse Pa and the Z-phase pulse Pz
Is supplied to the mechanical control unit 26.

A-phase pulse P supplied to PLL circuit 30
a is output as a pixel clock CK multiplied by the PLL circuit 30 so as to correspond to the resolution (recording resolution) of an image to be recorded on the printing plate 12.

Here, the signal processing unit 28A basically includes the RE electric unit 58, the PLL circuit 30,
An image memory 44 as image data storage means using a pixel clock CK as a recording synchronization signal supplied from the PLL circuit 30 as a read signal.

In the image memory 44, image data which is halftone image data to be recorded on the printing plate 12 is written from a host computer.

In this case, the image memory 44 uses the pixel clock CK output from the PLL circuit 30 as a read address.
(Here, binary data having a value of “0” or “1”) output from the laser diode 3
6 is supplied to a laser diode driving circuit (laser driver unit) 46 which is a driving means (optical system driving means), and an on / off signal corresponding to the image data is supplied to a laser diode 36 constituting the optical unit 34.

At this time, a light beam L, which is a laser beam that is turned on and off, is emitted from the laser diode 36 and is irradiated on the printing plate 12 via the imaging optical system 38. Thus, an image (halftone image) based on the image data is recorded on the printing plate 12.

The light beam image recording apparatus 10A according to this embodiment is basically configured as described above.

Next, the operation of the light beam image recording apparatus 10A will be described.

When a power switch (not shown) is turned on, DC power is supplied to each unit from the power supply unit 23 A, and AC power is supplied to the drum motor 20 from the AC power supply unit 52.

At this time, the sub-scanning motor 40 is driven under the action of the mechanical control unit 26, and the optical unit 3
4 is returned to the origin position where the origin detector 42 is located. Further, the rotation of the drum 14 is started through the drum motor 20.

On the other hand, when DC power is supplied from the power supply unit 23A to the RE light source 124 constituting the RE electric unit 58, the laser diode constituting the RE light source 124 continuously emits light in the laser oscillation region. The continuous light is supplied to the optical fiber 138 (see FIG. 3), the optical fiber cable 120, and the optical fibers 100 and 102 as light La and Lz.

The lights La and Lz are irradiated through the light projecting lenses 70 and 72 to the rotating encoding plate 64 which rotates integrally with the drum 14.

When the light transmitting portion 60 formed on the encoding plate 64 and the A-phase slit 80 formed on the slit plate 78 come to face each other, and when the light transmitting portion 62
And the Z-phase slit 84 face each other, the transmitted light is transmitted through the light receiving lenses 90 and 92 to the optical signal La, respectively.
m, and enters the optical fibers 110 and 112 as an optical signal Lzm.

The optical signal Lam and the optical signal Lzm are converted into an A-phase pulse Par and a Z-phase pulse Pzr of the optical signal, respectively.
The photodiode 134 which is guided to the outside of the E optical unit 56, is guided through the optical fiber cable 120, is guided into the electromagnetic shield case 140 of the signal processing unit 28A through the optical fiber 138, and forms the light receiving unit 122,
136 respectively.

The photodiodes 134 and 136 convert the A-phase pulse Par and the Z-phase pulse Pzr of the optical signal into current signals, respectively, and this current signal is converted into a voltage signal by a current-voltage conversion circuit (not shown). And the PLL circuit 3
0 is supplied to the mechanical control unit 26 as an A-phase pulse Pa and a Z-phase pulse Pz.

In this case, the mechanical control unit 26
Performs feedback control on the drum motor 20 based on these pulses to rotate the drum motor 20 at a constant rotation speed.

Further, the sub-scanning motor 40 is moved by feed-forward control.

The pixel clock C output from the PLL circuit 30 in synchronization with the transfer and the rotation of the drum motor 20
Image data (halftone image data consisting of values 0 and 1) is read from the image memory 44 using K as an address,
It is supplied to the LD driver unit 46.

The laser diode 36 constituting the optical unit 34 is controlled to be turned on / off by an image signal to be turned on / off from the LD driver unit 46, and the light beam L is irradiated on the printing plate 12 rotating in the main scanning direction X. Thus, a two-dimensional image is formed on the printing plate 12.

As described above, according to the above-described embodiment,
The optical unit 3 rotates the printing plate 12 held on the outer peripheral surface 16 of the drum 14 rotated by the drum motor 20.
By scanning in the main scanning direction X with the light beam L output from 4 and recording an image, the optical unit 34 is moved by the sub-scanning motor 40 in the sub-scanning direction Y substantially orthogonal to the main scanning direction X. A two-dimensional image can be formed on the printing plate 12.

The light beam scanning image recording apparatus 10 as described above
In A, a rotary encoder 54 that detects the rotational position of the rotating shaft 18 of the drum 14 and a pixel clock CK based on the A-phase pulse Pa and the Z-phase pulse Pz that are the rotational position detection signals detected by the rotary encoder 54 are used. There is provided a signal processing unit 28A for reading out an image signal from the image memory 44 and supplying it to the optical unit 34 as image recording means.

In this case, the rotary encoder 54
An RE optical unit 56 consisting of only an optical system for detecting the position of an encoding plate 64 which is a disk mounted and rotating in alignment with the shaft 18 of the drum 14, and one end of which is optically connected to the RE optical unit 56. An optical fiber cable 120 and an RE electric unit 58 optically connected to the other end of the optical fiber cable 120 are provided.

The RE electric unit 58 includes a RE light source 124 such as a laser diode for irradiating the input plate La constituting the RE optical unit 56 with the optical input signals La and Lz through one end of the optical fiber cable 120.
An encoding plate 64 output from the RE optical unit 56 and introduced through the other end of the optical fiber cable 120
And a light receiving unit 122 that converts the A-phase pulse Par and the Z-phase pulse Pzr of the optical signal whose light intensity changes according to the rotational position of the optical signal into the A-phase pulse Pa and the Z-phase pulse Pz, which are electric signals.

As described above, the optical fiber cable 12 is connected to the encoding plate 64 constituting the RE optical unit 56.
Since the RE light unit 124 and the light receiving unit 122 are provided in the RE electric unit 58 that is optically connected through the RE 0, the RE optical unit 56 and the RE electric unit 58 are provided.
A phase pulse Pa, which is a stable rotation position detection signal without electromagnetic noise from the RE optical unit 56 to the RE electric unit 58,
A Z-phase pulse Pz can be obtained. In other words, an electric signal that is faithful to the pattern formed on the encoding plate 64 can be obtained.

As a result, the fluctuation of the A-phase pulse Pa and the Z-phase pulse Pz due to the electromagnetic noise is almost eliminated.
The possibility that noise is mixed into the image formed on the printing plate 12 is reduced as much as possible, and the graphic accuracy of the image formed on the printing plate 12 is improved.

The present invention is not limited to the above-described embodiment. For example, in the light beam image recording apparatus 10A shown in FIG. 1, the signal processing unit 28A, the LD driver unit 46 and the optical unit 34 are respectively provided with a blowing signal. It is a matter of course that various configurations can be adopted by substituting the processing unit, the inkjet driver, and the inkjet head without departing from the gist of the present invention, such as application to an inkjet external surface scanning type image recording apparatus.

Such an ink-jet outer surface scanning type image recording apparatus can be used as a printing machine with the same configuration.

As described above, the present invention can be applied to various image recording apparatuses requiring correction of a drum system, such as a light beam recording method and an ink jet recording method.

[0084]

As described above, according to the present invention, the rotary encoder is separated into the optical unit and the electric unit, and only the optical unit is mounted on the shaft of the rotary drive source, so that high noise is generated. Only the optical unit can be arranged around the drum, and the electric unit is not affected by electromagnetic noise.

As a result, in the electric unit, a pulse (signal) faithful to the pattern drawn on the encoding plate can be obtained, and a stable recording operation can be performed.

Moreover, according to the present invention, unnecessary radiation is eliminated from the cable (optical fiber cable) between the optical unit and the substrate on which the signal processing unit is mounted, and concerns about magnetic influences to the outside are eliminated. .

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of a light beam image recording apparatus to which an embodiment of the present invention has been applied.

FIG. 2 is a perspective view showing a schematic configuration of an optical unit of a rotary encoder in the example of FIG.

FIG. 3 is an explanatory view of a mounting configuration of an optical unit and an electric unit of the rotary encoder.

FIG. 4 is a schematic block diagram showing a configuration of an external surface scanning light beam image recording apparatus to which a conventional technique is applied.

[Explanation of symbols]

10A: light beam scanning image recording device 12: printing plate (sensitive material, recording sheet) 14: drum 16: outer peripheral surface 34: optical unit 40: sub-scanning motor 54: rotary encoder (RE) 56: RE optical unit 58: RE Electrical unit 64 Encoding plates 70, 72, 74 Projection lens 78 Slit plate 90, 92, 94 Light receiving lens 120 Optical fiber cable 122 Light receiving unit 124 RE light source 134, 136 Photodiode (light receiving element) Pa: A-phase pulse Par: A-phase pulse of optical signal Pz: Z-phase pulse Pzr: Z-phase pulse of optical signal

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2C362 BB46 BB47 CB59 EA11 2F065 AA07 AA39 BB03 BB16 BB27 DD04 DD11 FF17 GG06 HH03 HH13 JJ01 JJ05 JJ09 JJ18 LL02 LL28 MM04 PP13 UU05 UU07 CA03 EB02 CA03 EB16 EB32 EB33 EC03 EC04 EC08 ED11 ED15 FA02 2H045 AG09 CA85 DA02 DA41 5C072 AA03 BA11 DA07 HA02 JA02 JA06 JA08 JB03 JB07

Claims (4)

[Claims] A rotatable encoding plate provided with a plurality of light intensity modulating portions in a circumferential direction; a light projecting means for projecting light to the light intensity modulating portion of the encoding plate; Light receiving means for receiving light emitted from the light emitting means and obtained through the light intensity modulating unit; a light supply optical fiber for supplying light to the light emitting means; and light received by the light receiving means A rotation position detecting device, comprising: a light deriving optical fiber for deriving an optical signal, wherein only an optical signal, not an electric signal, is input / output through the light supplying optical fiber and the light deriving optical fiber. 2. The rotational position detecting device according to claim 1, wherein the light intensity modulating unit is a light transmitting unit or a light reflecting unit. 3. An optical unit comprising only an optical system for detecting a rotational position of an encoding plate provided with a plurality of light intensity modulating sections in a circumferential direction, and one end optically connected to the optical unit. An optical fiber cable; and an electrical unit optically connected to the other end of the optical fiber cable, wherein the electrical unit comprises: A light source for irradiating an optical input signal through the one end of the cable, and a rotation position of the encode plate output from the light intensity modulator of the encode plate and introduced through the other end of the optical fiber cable. A light receiving unit that converts an optical signal whose light intensity changes into an electric signal. 4. An image recording device scans a recording sheet held on an outer peripheral surface of a drum rotated by a rotary drive source in a main scanning direction to record an image, and the image recording device controls the image recording device. In an image recording apparatus that forms a two-dimensional image on the recording sheet by moving in a sub-scanning direction substantially orthogonal to a scanning direction, a rotation position detection device that detects a rotation position of a rotation axis of the drum, A signal processing unit that reads an image signal from an image memory based on the rotation position detection signal detected by the rotation position detection device and supplies the read image signal to the image recording unit, wherein the rotation position detection device is connected to the axis of the drum. An optical unit consisting of only an optical system for detecting the rotational position of an encoding plate provided with a plurality of light intensity modulating units in the circumferential direction An optical fiber cable having one end optically connected to the optical unit; and an electric unit optically connected to the other end of the optical fiber cable, wherein the optical unit comprises the optical unit. A light source for irradiating the light intensity modulation section of the encoding plate with an optical input signal through the one end of the optical fiber cable; and a light source output from the light intensity modulation section of the encoding plate and the other end of the optical fiber cable. And a light-receiving unit that converts an optical signal whose light intensity changes according to the rotational position of the encoding plate introduced through the optical signal into an electric signal, and supplies the electric signal to the signal processing unit as the rotational position detection signal. An image recording apparatus comprising: an electric unit.