JPH078211Y2 - Optical writing system optical position adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a position adjusting device for an optical writing unit and a printing unit of an optical writing printer.

[Prior art]

The optical writing printer normally controls the opening and closing of the liquid crystal shutter provided in the print head to irradiate the transmitted light of the light from the light source onto the photosensitive drum by the imaging lens also provided in the print head. Record images,
After that, the image is reproduced on paper according to a known PPC process.

In the above-mentioned optical writing printer, whether or not the light passing through the micro shutter is accurately irradiated onto the photosensitive drum is a big problem. For this reason, the positions where the print head and the photoconductor drum are disposed are extremely important, and the positions are adjusted in the conventional manner as follows.

First, a CCD (charge coupled device) is placed using a jig or the like at the light irradiation position of the imaging lens, that is, the exposure position on the surface of the photoconductor drum, and the light actually transmitted through the micro shutter is transferred to the imaging lens. While irradiating the light receiving surface via the CCD, the position of the print head and the photosensitive drum is adjusted by moving the print head up and down so that the amount of light received by the CCD is maximized by the oscilloscope connected to the CCD.

[Problems of conventional technology]

However, in the conventional position adjusting device as described above, as shown in FIG. 7, the CCD is a sensor 40 provided in a line in the X direction (main scanning direction), and is actually provided in the liquid crystal shutter. Since the micro-shutters 41a that transmit light to are arranged in a row in the same X direction as shown in the figure, it is good if the sensor 40 is arranged at the position shown by the solid line, but in the Y direction ( In the sub-scanning direction), that is, when the position is shifted to the dotted line position 40 ', the sensor 40 cannot detect the amount of received light, so it is necessary to adjust the position of the print head also in the Y direction shown in FIG.

Further, as shown in FIG.
When arranged in rows, both rows of micro shutters 41
In order to measure the light intensity of a and 41b, for example, the sensor 40 is also Y
Since the micro shutters 41a and 41b have an interval on the order of μm, the adjustment is extremely difficult.

[Purpose of device]

In view of the above-mentioned conventional drawbacks, the present invention provides a sub-scanning direction (Y direction) when adjusting the positions of the print head and the photosensitive drum.
The purpose is to simplify the adjustment by eliminating the need for position adjustment with respect to.

[Key points of device]

In order to achieve the above object, the present invention includes a print head that supports an optical writing element array arranged in a plurality of rows in parallel with a rotation axis of a photoconductor drum so as to face an exposed surface of the photoconductor drum. In a position adjusting device for an optical system of an optical writing printer which selectively performs an optical writing operation on each element of a writing element array to perform image exposure on the exposed surface, a light receiving element substrate holding a light receiving element array arranged in a straight line, Supporting means for the light receiving element substrate, which aligns the light receiving element array with the exposed surface and supports the light receiving element array in a direction intersecting the projected images of the plurality of rows of optical writing element arrays, and an output of the light receiving element array. It is characterized by comprising a light quantity measuring means for measuring the intensity and an adjusting means for adjusting the position of the print head with respect to the exposed surface.

[Example of device]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic configuration diagram for explaining an example of a liquid crystal printer as an image forming apparatus incorporating the optical system position adjusting device according to the present invention.

In the figure, a photosensitive drum 1 is rotatably supported at a substantially central portion of a liquid crystal printer, and is rotationally driven at a predetermined speed in a direction of an arrow. In the vicinity of the peripheral surface of the photoconductor drum 1, a charger 2 for uniformly charging the peripheral surface of the photoconductor drum 1 to a predetermined polarity, a liquid crystal shutter, and the like are installed along the rotation direction thereof, and input. A print head 3 that forms an electrostatic latent image by irradiating the surface of the photosensitive drum 1 with an optical signal corresponding to image information, a developing unit 4 that supplies toner to the formed electrostatic latent image to form a toner image, and toner. A transfer device 5 for transferring the image to the transfer paper T and a cleaner 6 for removing the toner remaining on the photosensitive drum 1 without being transferred after the transfer are provided.

Further, in the transfer paper transport path, a paper feed cassette 7 in which the transfer papers are stacked and stored, a paper feed roller 8 that carries the transfer paper T out of the paper feed cassette 7, and the transfer paper T is transported toward a turn guide 9. Transport roll 10, a fixing device 11 for thermally fixing the toner image on the transfer paper after transfer, a discharge roller 13 for discharging the transfer paper T to the outside of the machine, and a discharge paper for stacking the discharged transfer paper T It is formed of the portion 14 and the like.

Further, FIG. 3 is a cross-sectional view showing the internal structure of the print head 3 described above and the relationship of arrangement with the photoconductor drum 1. In the figure, the print head 3 is covered with a casing 15 and a head base 16, and a lamp case 18 is provided with a fluorescent lamp 17 provided inside the lamp guide 17a, and the above-mentioned fluorescent lamp 17 is provided.
A liquid crystal shutter panel 19 for modulating the light from the light source according to the recorded information, an imaging lens 20 for forming an image of the modulated light on the photosensitive drum 1, and opening and closing a large number of micro shutters (not shown) in the liquid crystal shutter panel 19. A drive substrate 21b on which a controlling LSI 21a is arranged, the drive substrate 21b and a liquid crystal shutter panel 19
It has a built-in heat seal 21c and so on.

On the other hand, the photosensitive drum 1 is arranged at the position shown by the dotted line in the figure. In the present embodiment, a CCD (charge coupled device) 22 having a light receiving surface is arranged at a position A on the photosensitive drum 1 where the transmitted light from the liquid crystal shutter panel 19 is exposed via the imaging lens 20. . And this CCD22 is CCD
A plurality of CCD substrates 24 are provided on the unit 23. The CCD unit 23 is guided by a guide rail 25 provided in the main body of the liquid crystal printer so as to be movable in the direction perpendicular to the paper surface of the drawing. In addition, the CCD unit 23 should be positioned so that the position of the CCD unit 23 does not cause vertical error.
A leaf spring 26 is provided between the upper surface of the CCD and the guide rail 25, and always urges the CCD unit 23 downward.

The arrangement direction of the light receiving elements forming a part of the CCD 22 described above and the arrangement direction of the micro shutter in the liquid crystal shutter panel 19 are configured as shown in FIG. FIG. 4 shows only the arrangement relationship between the above-mentioned light receiving element and the micro shutter as seen from the direction B in FIG. In this embodiment, the micro shutters 27 are arranged in two rows, and the light receiving element is composed of run sensors 1 arranged in a line.

Further, the arrangement direction C of the light receiving elements (line sensor 1) is configured to be inclined by an angle θ _{1 with} respect to the arrangement direction X of the micro shutter. For example, assuming that the array of line sensors ₁ is arranged at the angle θ ₁ as described above, the array of line sensors ₁ is arranged as shown in FIG.
It is arranged so as to attach importance to.

On the other hand, the print head 3 and the CCD substrate 24 having the above-mentioned configuration
The position adjusting member 28 and the measuring circuit as shown in FIG.
29 are provided.

The measurement circuit 29 and the CCD substrate 24 are connected by a lead wire 30, and in synchronization with a timing signal from a synchronization control circuit 33, which will be described later, the CCD drive circuit 34 gives a drive signal to the CCD 22 to change the light amount received by the CCD 22. A corresponding electric signal is output to the CCD output amplifier circuit 31. The CCD output amplification circuit 31 amplifies the above-mentioned output signal to a predetermined output level and outputs the amplified signal to the oscilloscope 32. Also, in the synchronous control circuit 33
A timing signal for reading the output signal from the CCD 22 is output to the CCD output amplification circuit 31, and a trigger is given to the oscilloscope 32 in synchronization with the timing signal.
Display the output signal level on the display surface of.

On the other hand, the print head 3 is attached so as to be movable up and down with respect to a projecting plate 35 provided on the liquid crystal printer body. That is, a pin 36 that is integrally erected on the projecting plate 35 is loosely fitted in a fixing hole provided in the supporting plate 3a that supports the print head 3, and a spring 37 is provided between the supporting plate 3a and the projecting plate 35.
, And the pin 36 is threaded so that the position of the head base can be adjusted by tightening the nut 38.

An explanation will be given below of the operation when the position adjustment between the print head 3 and the photoconductor drum 1 is performed using the above-mentioned constitution in which the CCD 22 is arranged on the light receiving surface of the photoconductor drum 1 in the above-mentioned configuration.

First, the CCD unit 23 to which the CCD 22 is attached is inserted toward the guide rail 25 for supporting the substrate of the liquid crystal printer body from which the photosensitive drum 1 is removed, and the line sensor 1 on the CCD 22 is attached to the surface of the photosensitive drum 1. Set so that it will come to the position corresponding to the image point. After that, the light source 17 in the print head 3 is turned on and the micro shutter is driven to open, and the transmitted light of the micro shutter 27 is formed on the line sensor l. Then, an output corresponding to the amount of light received by the line sensor 1 is output to the CCD2
As described above, the signal is supplied from 2 to the CCD output amplifier circuit 31, the output signal is amplified and then output to the oscilloscope 32, and the waveform displayed on the oscilloscope 32 is observed to make adjustment. Here, when the imaging lens 20 correctly forms an image of the transmitted light of the micro shutter on the line sensor 1, the oscilloscope 32
The amplitude of the waveform displayed at is maximum, for example, as shown by the solid line in FIG. Also, if the positions do not match even a little, the amplitude of the above waveform becomes small. Therefore, the nut 38 is turned so as to maximize the output, and the position (height) of the print head 3 is moved up and down to set the print head 3 at the optimum position. This adjustment is extremely easy because it only needs to be adjusted to maximize the waveform.

On the other hand, as shown in FIG. 4, even if the positions of the micro-shutters 27a and 27b and the position of the line sensor 1 are deviated, for example, the line sensor 1 is deviated to the position l ₁ or l ₂ , the micro-shutter 27a does not operate. , 27b are arranged at an angle of θ _{1 with} respect to the arrangement direction (X direction), so that one of the micro-shutters 27a, 27b in each row is covered, so that the light amount can be measured reliably. Therefore, the line sensor l (CC
The arrangement position of D22) is not required to be accurate in the Y direction as in the conventional example.

By the way, when the line sensor 1 is displaced to the position l ₁ as described above, the amplitude of the waveform displayed on the oscilloscope 32 becomes small, as shown by the dotted line in FIG.
Even in this case, the position may be adjusted simply by adjusting the position of the print head 3 so that the peak position P ′ of the output waveform is maximized.

Further, as shown by a dotted line in FIG. 4, Ransensa l 'when a is disposed at an angle theta ₂ with respect to the X direction, the line sensor l' micro shutter 27a, respectively and 27b 2 In this case, the oscilloscope is used.
The waveform displayed on the screen is, for example, as shown in FIG. 5 (b), and in this case as well, it is the same to adjust the peak value P ″ to be maximum.

Then, the line sensor l or l'and the micro shutter
The range of the angle θ in which 27a and 27b always overlap with each other is calculated below.

B) First, as shown in the above example, the micro shutter 27
When a and 27b are two lines and are in a staggered arrangement. In this case, for example, as shown in FIG. 6A, the widths of both the micro shutters 27a and 27b are the same A × B, and the micro shutter 27
If the pitches of a and 27b are C and D, The angle θ may be set to.

B) Next, when the micro shutter 27 has one line.

In this case, for example, if the size of the 1-dot micro-shutter 27 is A × B and the pitch of each micro-shutter is C, as shown in FIG. 7B, the angle is 0 <θ <tan ⁻¹ A / C. It suffices to set θ.

As described above, in the case of 1 run or 2 lines, if the angle θ is set to the above-mentioned angle, the line sensors 1 and 1'are set to the micro shutter 2
The light always overlaps with 7, 27a and 27b, and the light input through the micro shutter always enters the line sensors l and l '.

In the above example, the micro shutters are arranged in one line or two lines, but the number of lines is not limited to this.

As described above, in this embodiment, the line sensor 1,
By setting l'and mounting it on the CCD board 23,
It can always receive the transmitted light from the micro shutter and does not need to move the CCD to accurately and easily adjust the position of the print head.

[Effect of device]

As described in detail above, according to the present invention, since it is only necessary to adjust the print head so that the oscilloscope waveform is maximized, the work of adjusting the print head position can be simplified, and the CCD unit with the CCD attached Since the set of can be rough, the adjustment work time can be shortened.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the position adjusting device of the present embodiment, FIG. 2 is a schematic configuration diagram of a liquid crystal printer using the position adjusting device of the present embodiment, and FIG. 3 is printing of the position adjusting device of the present embodiment. FIG. 4 is a configuration diagram showing an arrangement relationship between a head and a CCD, FIG. 4 is an arrangement configuration diagram of a micro shutter and a line sensor, and FIGS. 5 (a) and 5 (b) are characteristic diagrams of a light amount display displayed on an oscilloscope. FIGS. 6 (a) and 6 (b) are diagrams for explaining a disposition arithmetic expression of a micro shutter and a line sensor, and FIG. 7 is a disposition configuration diagram of a conventional micro shutter and a line sensor. 3 ... Print head, 3a ... Support plate, 22 ... CCD, 23 ... C
CD unit, 24 …… CCD substrate, 29 …… Measuring circuit, 31 …… C
CD output amplifier circuit, 32 …… oscilloscope, 33 …… synchronous control circuit, 34 …… CCD drive circuit, 35 …… protruding plate, 36 …… pin, 37 …… spring, 38 …… nut.

Claims (1)

[Scope of utility model registration request] 1. A print head for supporting an optical writing element array arranged in a plurality of rows in parallel with the rotation axis of the photoconductor drum so as to face an exposed surface of the photoconductor drum, and each element of the optical writing element array. In an optical system position adjusting device of an optical writing printer which selectively performs an optical writing operation to perform image exposure on the exposed surface, a light receiving element substrate holding a light receiving element array arranged in a straight line, and the light receiving element array are Supporting means for the light-receiving element substrate, which is aligned with the exposure surface and supports the light-receiving element array in a direction intersecting the projected images of the plurality of rows of optical writing element arrays, and light quantity measurement for measuring the output intensity of the light-receiving element array An optical system position adjusting device for an optical writing printer, comprising: a means and an adjusting means for adjusting a position of the print head with respect to the exposed surface.