JP2002307749A - Image exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the image quality of exposure images of an image exposure device. SOLUTION: There are provided in the image exposure device, a beam scanning means BS for scanning an exposure light beam LB in a horizontal scanning direction to a photographic material, an optical sensor 7 for detecting that the exposure light beam LB is applied to a set position in its scanning range, and an exposure control means EC for controlling an exposure timing of image information by the beam scanning means BS on the basis of a detect signal of the optical sensor 7. A noise resistance improvement means NR is set to the image exposure device for improving the resistance to extraneous noises in the detect signal received from the optical sensor 7 by the exposure control means EC.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam scanning means for scanning a photosensitive member with a light beam in a main scanning direction, and detecting that the light beam is applied to a set position in a scanning range of the light beam. The present invention relates to an image exposure apparatus provided with an optical sensor for controlling the exposure of the image information by the beam scanning unit based on a detection signal of the optical sensor.

[0002]

2. Description of the Related Art In such an image exposure apparatus, for example, in a case where a photosensitive member is moved in a sub-scanning direction, a light beam is scanned in a main scanning direction, and the photosensitive member is moved in a sub-scanning direction. An image is formed two-dimensionally on the top. In such an exposure method, it is necessary to accurately detect the scanning position of the light beam in order to form an exposure image at an appropriate position on the photoconductor. For this purpose, the image exposure apparatus is provided with an optical sensor for detecting that the light beam has been applied to the set position in the scanning range of the light beam, and the exposure control means performs the control based on the detection signal of the optical sensor. Thus, the exposure timing of the image information is controlled. By the way, conventionally,
Since the signal level of the output signal from the optical sensor can be set to a relatively high level, the transmission and reception of the signal between the optical sensor and the beam scanning means has not taken any noise countermeasures.

[0003]

However, in the above-described conventional configuration, the frequency of occurrence of one image during exposure of several tens of images is very low. A phenomenon that the image for the line is slightly displaced in the main scanning direction occurs, and there is a problem that the image quality is deteriorated. The present invention has been made in view of such circumstances, and an object thereof is to improve the quality of an exposed image.

[0004]

According to the first aspect of the present invention, there is provided a beam scanning means for scanning a light beam in a main scanning direction with respect to a photoreceptor, and a scanning range of the light beam for the light beam. An image sensor provided with an optical sensor for detecting that the light beam has been irradiated to the set position, and an exposure control means for controlling an exposure timing of image information by the beam scanning means based on a detection signal of the optical sensor. In the apparatus, noise immunity improving means for improving immunity to external noise in the detection signal received by the exposure control means from the optical sensor is provided.

That is, as a result of the research by the inventor of the present invention, the timing of the occurrence of the malfunction of the beam scanning means or the like such that the image of one line is displaced as described above is determined by the power provided in the image exposure apparatus. There was a certain correlation with the operation of the device, and it was possible to find out that the noise generated by the power unit caused the malfunction. Further, as a result of further research, they have found that noise generated by the power unit has penetrated from a signal line connecting the optical sensor and the exposure control means. Therefore, by providing noise immunity improving means for improving immunity to external noise in the detection signal received from the optical sensor by the exposure control means, it is possible to prevent the above malfunction and improve the quality of an exposed image. Was.

In addition, with the configuration according to the second aspect, the noise immunity improving means outputs the detection signal of the optical sensor to a pair of signal lines, and the exposure control means side controls the pair of the signal lines. It is configured to differentially detect between signal lines. That is, in order to improve the resistance of the detection signal received from the optical sensor by the exposure control means to external noise, it is conceivable to connect the optical sensor and the exposure control means by, for example, a shield line. As a result of a study by the inventor of the present invention, a measure against noise that merely uses a shielded wire is not enough to reliably suppress the above-described malfunction, and a pair of signals connecting the optical sensor side and the exposure control means side is used. They have found that it is necessary to detect extraneous noise by detecting differentially between lines. By taking such noise countermeasures, it is possible to reliably prevent the above malfunction and improve the quality of an exposed image with high stability.

[0007] With the above configuration, the means for improving noise immunity is provided on the optical sensor side.
A differential driver that distributes the detection signal of the optical sensor to the pair of signal lines as a pair of signals inverted from each other and outputs the pair of signal lines, and differentially detects an output signal of the differential driver on the side of the exposure control unit; A differential receiver is provided and configured. Therefore, by using the above differential driver and differential receiver, noise components and signal components can be efficiently removed, and external noise can be more reliably removed from the detection signal of the optical sensor. It became. As a result, it is possible to more reliably prevent the erroneous operation and improve the quality of an exposed image with stability.

According to the fourth aspect of the present invention, there is provided a transport means for transporting the photosensitive member via the light beam exposure position by driving a pulse motor. That is, for example, a pulse motor for switching the transport roller between a pressure-bonding state and a pressure-releasing state, and a transport roller for driving the transport roller to transport the photoreceptor via the exposure position by the light beam. In many cases, a pulse motor is used as a power source, such as a pulse motor for driving. The inventor of the present invention has found that when a pulse motor is employed as the power source of the transport means, the above-described malfunction is likely to occur.
Therefore, in such a case, it is extremely effective to take measures against noise by the above-described noise tolerance improving means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the image exposure apparatus of the present invention is provided in a photographic printing apparatus will be described below with reference to the drawings. Photographic printing apparatus DP exemplified in this embodiment
Is a so-called digital minilab machine, and reads a frame image of a developed photographic film 1 (hereinafter simply referred to as "film 1") as shown in the block diagram of FIG. Film scanner FS
And an image exposure device EP that exposes a frame image read by the film scanner FS to the photographic paper 2 as the photoconductor PS and develops the image. [Schematic Configuration of Film Scanner FS] As schematically shown in FIG. 3, the film scanner FS includes a halogen lamp 10, a dimming filter 11 for adjusting the color balance of light emitted from the halogen lamp 10, Mirror tunnel 12 that evenly mixes light passing through dimming filter 11
A film mask unit 13 provided with a transport mechanism 13a and a film mask (not shown) for positioning the film 1 at a predetermined reading position, and a CCD line sensor unit 14 for photoelectrically converting a frame image of the film 1
And the image of the film 1 is transferred to the CCD line sensor unit 1
A lens 15 for forming an image on the optical path 4, a mirror 16 for bending the optical path by 90 degrees, a processing circuit 17 for amplifying and A / D converting the output signal of the CCD line sensor unit 14, and the processing circuit 17 A scanner control unit 18 that generates exposure image data for the image exposure apparatus EP based on the output signals of the image exposure apparatus EP and controls the operation of each unit in the film scanner FS; a simulated image simulating a finished print image; And a console 20 for inputting manual setting of exposure conditions and the like to the scanner control unit 18 are provided.

The CCD line sensor unit 14 has about 5
CCD line sensors in which 000 CCD elements are arranged in the width direction of the film 1 are arranged in three rows.
Red, green, and blue color filters are formed on the light receiving surface of the D-line sensor, respectively. In the film scanner FS, when the film 1 is set in the film mask unit 13, the transport of the film 1 is started by the transport mechanism 13a, and the frame images are sequentially read and read as digital image data for each of red, green, and blue. Output to the scanner control unit 18.

The scanner controller 18 calculates and obtains a simulated image that would be obtained when a print is created based on the image data input from the processing circuit 17, and displays it on a monitor 19. The operator observes the simulated image on the monitor 19, and if an appropriate image is not obtained, performs an operation for correcting the exposure condition from the console 20. The scanner control unit 18 generates exposure image data for each of red, green, and blue under predetermined calculation conditions according to the image data input from the processing circuit 17 and the correction input. Although a detailed description is omitted, the film scanner FS includes a magneto-optical disk or a CD-ROM.
A reading device for reading various types of storage media such as, for example, can produce prints based on image data recorded on those media in addition to the frame images of the film 1.

[Overall Configuration of Image Exposure Apparatus EP] As shown in FIG. 4, the image exposure apparatus EP is configured separately from a film scanner FS.
An image exposure unit 25 as a beam scanning means BS for forming an exposure image on the photographic paper 2 by scanning the photographic paper 2 with a light beam, and developing the photographic paper 2 exposed by the image exposure unit 25 And a photographic paper transport system PT for transporting the photographic paper 2 drawn from the photographic paper magazine 5 to the development processing unit 26. The developing processing unit 26 develops the outside of the housing. A sorter 3 for classifying the photographic paper 2 by order, and a conveyor 4 for transporting the photographic paper 2 discharged from the development processing unit 26 to the sorter 3, and an exposure control unit for controlling these units. 6
Is provided in the housing. Further, in the middle of the transport path of the photographic paper transport system PT, a cutter 28 for cutting the long photographic paper 2 pulled out from the photographic paper magazine 5 into a set print size, and a plurality of photographic papers 2 transported in a line are provided. And a sorting device 29 for sorting to the transfer rows.

[Arrangement Configuration in the Case of the Image Exposure Apparatus EP]
A front door 30 of a double-door type is provided on the front side of the housing of the image exposure apparatus EP. Inside the front door 30, as shown in FIG. At the lower end, a magazine storage unit ML for loading the photographic paper magazine 5 is arranged in a pair of left and right, and a space between the pair of left and right magazine storage units ML constitutes a part of the photographic paper transport system PT and includes a plurality of magazine storage units ML. A pre-exposure transport unit 32 that accommodates the transport rollers 24a and the like is arranged, and a control box 3 that accommodates the exposure control unit 6 is provided above the right magazine storage unit ML when viewed from the front.
4 are arranged.

An exposure transport unit 33 for transporting the photographic paper 2 at a location exposed by the image exposure unit 25 is disposed above the pre-exposure transport unit 32, and the image exposure unit 25 is disposed above a control box 34. Have been. The exposure transport unit 33 includes a plurality of transport rollers 2.
4b and the transport motor 2 that rotationally drives the transport roller 24b
3. Further, although not shown, a switching motor and the like for switching the transport roller 24b between the press-contact state and the press-release state are housed. The transport motor 23 and the switching motor are
It is composed of a pulse motor. The transport roller 24b, which is rotated by the drive of the transport motor 23, is switched to the pressure-bonded state by the drive of the switching motor to clamp the photographic paper 2, thereby transporting the photographic paper 2 via the exposure position by the light beam LB. Is done.

A first post-exposure transport unit 45 for receiving and transporting the photographic paper 2 exposed by the image exposure unit 25 from the exposure transport unit 33, and a second exposure unit are provided above the exposure transport unit 33 and the image exposure unit 25. A post-conveyance unit 46 and a third post-exposure conveyance unit 47 are arranged. First to third post-exposure transport units 45, 46, 47
Also, as with other transport units, a plurality of transport rollers 24
and the sorting device 29 is housed in the second post-exposure transport unit 46. An upper cover 31 for performing maintenance work on the first to third post-exposure transport units 45, 46, and 47 is provided on the upper side of the housing of the image exposure apparatus EP. Swinged open and closed.

[Configuration of Image Exposure Unit 25] Next, the configuration of the image exposure unit 25 will be described. The image exposure unit 25 in the present embodiment employs a so-called laser exposure method of exposing an image on the printing paper 2 using a laser as a light source, and its schematic configuration is shown in a block diagram of FIG. As shown in FIG. 1, the image exposure unit 25 includes a red laser light source 50r and a green laser light source 5 that respectively emit red, green, and blue monochromatic light as collimated light.
0g and blue laser light source 50b, and each laser light source 50b.
An acousto-optic modulator 51 (hereinafter abbreviated as “AOM element 51”) for intensity-modulating the emitted light of each of r, 50g, and 50b, and a light beam L emitted from the AOM element 51
Beam expander 52 for adjusting the beam diameter of B
A cylindrical lens 53, a prism 54 for combining the optical axes of the three red, green and blue light beams LB into one optical axis, a polygon mirror 55 for scanning the light beam LB, and f-θ. In addition to an imaging lens group 56 having characteristics and a tilt correction function, a mirror 57 for bending the optical path of the light beam LB and an aperture 58 for regulating light incident on the prism 54 are arranged. An optical sensor 7 for detecting that the LB has been irradiated to a set position (reference position) in the scanning range is provided.

The set position (reference position) to be detected by the optical sensor 7 is the installation position of the mirror 8 shown in FIG.
The installation position of the mirror 8 naturally falls within the scanning range of the light beam LB, but is located outside the scanning range in which the light beam LB irradiates the existing area of the printing paper 2. The light beam applied to the mirror 8 (in FIG. 1, for convenience, denoted by reference numeral “LB ′”) is reflected toward the light sensor 7, and the light sensor 7 detects the light beam LB ′. Is output as a pulse signal.

[Structure of Exposure Control Unit 6] As shown schematically in FIG. 1, the exposure control unit 6 controls the image exposure unit 25 having the above-described structure. Image data is stored in the image exposure unit 25
An image processing circuit 60 that performs a correction operation on image data taking into account the exposure characteristics of the image data; an image data memory 61 that stores the image data obtained by the image processing circuit 60 for each of red, green, and blue; And a D / A converter 62 provided for each of the colors blue and D / A converting the output data of the image data memory 61, and a control signal having an amplitude corresponding to an input signal from the D / A converter 62. And a timing control circuit 64 for controlling the switching timing of the signal sent from the D / A converter 62 to the AOM control circuit 63.

[Exposure Operation by Image Exposure Unit 25]
Next, the operation of the image exposure unit 25 and the exposure control unit 6 having the above configuration will be schematically described together with the operation of the exposure transport unit 33 as the transport unit ET that transports the photographic paper 2 at the location exposed by the image exposure unit 25. . The image data for exposure input from the film scanner FS is corrected and calculated by the image processing circuit 60, and is converted into image data which can obtain a good print image when exposed by the image exposure unit 25.
Are written sequentially. Data obtained as a result of the processing by the image processing circuit 60 becomes final data for setting the exposure amount for each pixel of the image to be exposed.

The data once stored in the image data memory 61 is stored in a timing control circuit 64 for each pixel data.
D / D in synchronization with the clock signal input from
The signal is sent to the A converter 62, converted to an analog signal, and then sent to the AOM control circuit 63. The timing control circuit 64 sets the transmission start timing of the clock signal to be transmitted to the image data memory 61 and the like based on the detection signal of the optical sensor 7. In other words, the exposure control unit 6 including the timing control circuit 64
Function as exposure control means EC for controlling the exposure timing of the image information by means of.

The optical sensor 7 and the timing control circuit 64 are connected via a differential driver 9a on the optical sensor 7 side and a differential receiver 9b on the exposure control section 6 side. The connection between the differential driver 9a and the differential receiver 9b in this way is to improve the resistance of the detection signal received from the optical sensor 7 to external noise by the exposure control means EC. The noise immunity improving means NR includes the differential receiver 9b. As the differential driver 9a and the differential receiver 9b, general ICs can be used. These are connected to a pair of signal lines 70 formed as a twisted pair line, as schematically shown in FIG. Connected. The differential driver 9a is
The detection signal of the optical sensor 7 illustrated in FIG.
In (b), the signals are distributed to the pair of signal lines 70 and output as a pair of inverted signals indicated by “A” and “B”. The differential receiver 9b differentially detects the output signal of the differential driver 9a and outputs a signal shown in FIG. Note that the signal shown in FIG. 6B illustrates the case of operating with a single power supply. However, when two positive and negative power supplies are used, the differential driver 9a uses “A” in FIG. 6B. ,
The signal “B” can be generated as a pair of signals whose polarities are inverted from each other.

The AOM control circuit 63 outputs a control signal having an amplitude corresponding to the input signal to the AOM element 51, and the AOM element 51 enters from the laser light sources 50r, 50g, and 50b with a diffraction index corresponding to the amplitude of the input control signal. Modulates the laser light to be emitted. Light beam LB modulated by AOM element 51
Is incident on the prism 54 after passing through the beam expander 52 and the like, and three red, green and blue light beams L
B is combined into one light beam LB, and is irradiated on the reflection surface of the polygon mirror 55.

The light beam LB reflected by the reflection surface of the polygon mirror 55 which is driven to rotate by the drive motor 55a
Is scanned in a plane orthogonal to the rotation axis of the polygon mirror 55, and the exposure and transport unit 3 is scanned by the imaging lens group 56.
The light is condensed on the photographic paper 2 conveyed at 3. Light beam L
The scanning direction of B intersects (more specifically, orthogonally) with the transport direction of the photographic paper 2, and the scanning direction of the light beam LB is the main scanning direction, and the transport direction of the photographic paper 2 is the sub-scanning direction. An image to be printed on the printing paper 2 is formed as a latent image by the scanning of the light beam LB and the conveyance movement of the printing paper 2.

[Other Embodiments] Hereinafter, other embodiments of the present invention will be listed. (1) In the above embodiment, as the noise immunity improving means NR, the differential driver 9a and the differential receiver 9b which are integrated into an IC are used.
Although the above example is used, a differential driver and a differential receiver may be configured by a non-inverting amplifier, an inverting amplifier, and a differential amplifier configured by an operational amplifier or the like.

(2) In the above embodiment, the differential driver 9a and the differential receiver 9b use the noise immunity improving means NR.
Is exemplified, but for example, the optical sensor 7
And the exposure controller 6 are connected by a pair of signal lines, and on the optical sensor 7 side, a detection signal of the optical sensor 7 is input to one of the pair of signal lines, and A configuration may be adopted in which a detection signal of a dummy optical sensor whose portion is shielded is input, and the exposure control unit 6 performs differential detection between the pair of signal lines.

(3) In the above embodiment, the differential driver 9a and the differential receiver 9b use the noise immunity improving means NR.
Is exemplified, but for example, the optical sensor 7
The specific configuration of the noise immunity improving means NR can be variously changed, for example, by arranging a signal line connecting the exposure control unit 6 and a signal wiring in a metal wiring duct. (4) In the above embodiment, the beam scanning means BS is configured to scan the light beam LB by the polygon mirror 55. However, the beam scanning means BS scans the light beam LB by a transparent plate having a diffraction grating. A hologram scanner may be used, or a specific configuration for scanning the light beam may be variously changed, such as a configuration in which the reflection mirror is swung by a driving force of an electromagnet or the like to scan the light beam LB. is there.

(5) In the above embodiment, the photographic paper 2 is exemplified as the photosensitive member. However, the present invention can be applied to various photosensitive members such as a photosensitive film. The present invention can also be applied to a laser printer that forms a latent image by irradiating a drum with a light beam and develops the latent image with toner. (6) In the above embodiment, the case where the beam scanning unit BS emits the light beams LB of three colors of red, green, and blue is exemplified, but the beam scanning unit BS is configured to emit the light beam of one color. May be. (7) In the above embodiment, the three light beams LB of red, green and blue are combined into one optical axis by the prism 54, but it is not always necessary to combine them into one optical axis.

[0028]

According to the first aspect of the present invention, the exposure control means includes noise immunity improving means for improving immunity to external noise in the detection signal received from the optical sensor, thereby causing malfunction of the beam scanning means and the like. Can be prevented and the image quality of the exposed image can be improved. According to the configuration of the second aspect, differential detection is performed between a pair of signal lines connecting the optical sensor side and the exposure control means side to strongly eliminate external noise, thereby more reliably. The above malfunction is prevented, and the image quality of the exposed image can be improved with good stability.

According to the configuration of the third aspect, by using the differential driver and the differential receiver, it is possible to efficiently remove a noise component and extract a signal component. External noise can be more reliably removed from the detection signal of the sensor, and the above-described malfunction can be more reliably prevented, and the quality of an exposed image can be improved with higher stability. According to the configuration of the fourth aspect, even when a pulse motor is employed as the power source of the transporting means for transporting the photoreceptor, the image quality of the exposed image can be improved by taking measures against noise by the noise immunity improving means. Can be improved.

[0030]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part according to an embodiment of the present invention.

FIG. 2 is an internal layout diagram of the image exposure apparatus according to the embodiment of the present invention;

FIG. 3 is a block diagram of a photographic printing apparatus according to an embodiment of the present invention.

FIG. 4 is an external perspective view of the image exposure apparatus according to the embodiment of the present invention.

FIG. 5 is a block diagram of a main part according to the embodiment of the present invention;

FIG. 6 is a signal explanatory diagram according to the embodiment of the present invention.

[Explanation of symbols]

 7 Optical Sensor 9a Differential Driver 9b Differential Receiver 70 A Pair of Signal Lines BS Beam Scanning Means EC Exposure Control Means ET Transport Means NR Noise Resistance Improvement Means PS Photoconductor

Continuing from the front page (72) Inventor Fumihiro Nakahara One Noritsu Koki Co., Ltd. at 579 Umehara, Wakayama City, Wakayama Prefecture F term (reference) 2C362 BA89 BB30 2H076 AB06 AB12 AB16 AB31 AB67 2H106 AB02 AB04 AB15 AB42 AB70 AB71 AB99 BA91

Claims (4)

[Claims] 1. A beam scanning means for scanning a photoreceptor with a light beam in a main scanning direction, and an optical sensor for detecting that the light beam is irradiated on a set position in a scanning range of the light beam. An exposure control unit for controlling an exposure timing of image information by the beam scanning unit based on a detection signal of the optical sensor, wherein the exposure control unit receives from the optical sensor An image exposure apparatus provided with noise immunity improving means for improving immunity to external noise in a detection signal. 2. The noise immunity improving unit is configured to output a detection signal of the optical sensor to a pair of signal lines, and to perform differential detection between the pair of signal lines on the exposure control unit side. The image exposure apparatus according to claim 1, wherein 3. The noise immunity improving means includes a differential driver on the optical sensor side, which distributes the detection signal of the optical sensor to the pair of signal lines as a pair of inverted signals and outputs the pair of signals. 3. The image exposure apparatus according to claim 2, wherein a differential receiver for differentially detecting an output signal of the differential driver is provided on the side of the exposure control means. 4. The image exposure apparatus according to claim 1, further comprising a transport unit configured to transport the photoconductor via an exposure position by the light beam by driving a pulse motor. .