DE4401731A1 - Optical scanner for digital copier or printer - Google Patents

Abstract

The scanner has an optical deflector (4) with a reflecting deflection surface. This is rotated at a constant speed. A light beam from a light source (1) is guided through the deflector (4) to a plane and is made incident on a reflective image generator via a mirror (6). The generator (7) is at an angle relative to a beam deflection surface.The light beam reflected from the generator (7) is reflected to the semi-transparent mirror (6) and is converged by image processing to a light point on a scanning surface to carry out an optical scanning process. The image generator (7) has the function of carrying out the scanning process with the help of light points at constant speed. The generator (7) is arranged such that it is shifted by a predetermined amount in a direction perpendicular to the deflection surface to correct bending of the scan lines on the scanning surface.

Description

The invention relates to an optical scanner according to the Ober Concept of claim 1, 2, 3, 8, 15, 20, 27, 28, 36, 37 or 38 and is particularly concerned with an optical scanner in which chem a light beam which is deflected by a deflection device is steered, which has a reflective deflection surface, the is rotated at a constant speed through the bil the production process of a reflective imaging element elements as a point of light on a surface to be scanned is embellished to a scanning process with a uniform Speed. The invention can be in one writing optical system in a digital copier, an optical printer / printer etc. and in an optical Ver scanning system in a measuring device, a display, etc. ver be applied.

As is generally known, there is one in an optical scanner fR lens as an optical system widely used to make a deflected beam of light as a point of light on an abta converging surface. Recently, instead of the fR Lens used a reflective imaging element the one that is an optical element that is a function of Reflect and converge the deflected light beam as has a light spot on the surface to be scanned. In this pa  This optical element becomes a reflective element Imaging element is called and is for example in the Japanese Patent Application Laid-Open (KOKAI) NO. 1-220 221 shown. Furthermore, a mirror surface shape of the reflek imaging element which, instead of the aforementioned fR- Lens is used, according to a proposal at an aspheric the surface used to preferably a field cloud exercise and correct a linearity of an image.

In the optical scanner, in which such a reflection rendes imaging element is used, the means the deflecting device deflected light beam through the reflec imaging element on one side of the deflection direction returned. Consequently, light path separation must be direction to be arranged around a light path of the light beam from the deflector to the reflective image gung element of the light path of the light beam from the reflec tive imaging element to the area to be scanned separate.

For example, one of the light path separators in Be traditional costume, in which the light beam strikes the right reflective imaging element strikes in one direction, which with respect to the axis of rotation of a reflective deflecting surface che is inclined in the deflector. In this case a preferred direction of the deflected light beam with respect to egg ner inclined to its axis of rotation vertical plane. In a such execution is the direction of the deflected light beam, which on the reflective imaging element strikes, not in accordance with that of light beam that re on the reflective imaging surface has been inflected, so that a light path of the incident reflected light beam from a light path of the reflected th light beam can be separated. However, if the light paths separated from each other only by such a separation device  must be an angle of the light beam, which on the right reflecting deflecting surface hits, with respect to the aforementioned Level to some extent enlarged to an interpretation to enable each of the optical elements. If this one if the angle is increased, the locus of a point of light strongly curved or arched on the scanned surface so that a scan line is strongly curved, and because of the curved th scanning line ver a perfect optical scanning process is prevented.

Various types of known optical scans are used regarding an optical printer / printer etc. with same angular velocity deflected light beam as a Point of light on a scanned surface converges to that to scan the scanned area. An fR lens is generally nen used as an optical system in which the abge directed light beam as a point of light on the scanned surface che converges, and an optical scanning process in which This point of light is used with a uniform Speed performed. Recently there is a reflect the imaging mirror, which has a linearity correction radio tion has been proposed and used instead of the fR lens. For example, this is a reflective imaging mirror in the aforementioned Japanese patent application (KOKAI) NO. 1- 200 221 shown.

In an optical scanner that has such a reflective Has an imaging mirror, a scan line tends to a moving locus of the point of light is straight, ge getting hunched over. In the description below this will be referred to as "a curve of the scan line".

In the optical scanner which produces the aforementioned images used are the reflected light beam, wel cher hits the imaging mirror, and the reflec  light beam that reflects on the imaging mirror is tiert, with respect to the imaging mirror on the same Side set. Consequently, an optical arrangement must be used be detected in which these light beams are separated from each other and the deflected and reflected light beam not traced back to the side of a light source, but are directed to a scanned surface side. This is a case where the scan line curvature is necessarily is caused by a certain optical arrangement.

Such a curvature of the scan line, which by the opti cal arrangement has been caused, can corri be that a position of the imaging mirror in a direction corresponding to a cross scan in the manner postponed that there were no practical problems become. Otherwise such a curvature of the scan line can also be corrected in that the imaging mirror is inclined to such an extent that no practical Problems. However, each optical element must be in one Light path from the light source to the area to be scanned very high accuracy can be arranged to the scan line Correct the curvature as it is designed. If consequently errors in the arrangement accuracy of the respective op table elements, there is a very large one Curvature of the scan line.

For example, such curvature of the scan line leads to serious difficulties in a two-color printer, etc., in which information of each color is written by means of a separate optical scanning process. For example, when a reference character L in Fig. 80 is set on an ideal scan line, there is a case that scan lines L ₁ and L ₂ are curved in opposite directions for writing information of each of the two colors. In such a case, a shift (d ₁ + d ₂ ) is a maximum at both end parts of an optical scanning area. As a result, a so-called color shift is clearly evident.

The object of the invention is therefore to provide an optical scanner create light paths by refraction or a light path separated by refraction and reflection. Furthermore, according to the Invention an optical scanner to be created to the crumb effective correction of a scan line, which by the The aforementioned separation of the light paths has been caused. In addition, an optical scanner according to the invention be created to achieve the above two objectives to achieve, and which also a function to the Cor rig the inclination of a reflective baffle in egg has a deflector. Furthermore, according to the invention optical scanner can be created, in which a reflection render imaging mirror used to the curvature a scan line caused by an error in the arrangement of an optical element has been effectively caused to reduce.

According to the invention, this is the case with an optical scanner the preamble of claim 1, 2, 3, 8, 15, 20, 27, 28, 36, 37 or 38 by the features in the characterizing part of each due claim achieved. Advantageous further developments are Subject of one of the above claims claims that are directly or indirectly related.

According to the invention, the light paths of the light beam from each other by refraction or by refraction and reflection be separated. It is also possible to measure the curvature of a sample line, which comes from the aforementioned separation of the light paths is called to correct effectively. In addition to these both effects, it is also possible to provide a function, around the inclination of the reflective deflection surface in the deflection to correct the facility. Furthermore, the curvature or bending  a scan line, which is caused by an error in the arrangement tion of an optical element is effective be reduced.

The invention is based on preferred embodiments tion forms with reference to the accompanying drawings in individual explained. Show it:

Fig. 1a to 1d views, based on which first to seventh versions of an optical scanner according to the invention are explained;

Fig. 2a to 2c diagrams, on the basis of which correction successes with respect to the curvature of a scanning line are explained using an example of the first and second embodiments of the invention;

FIGS. 3a to 3c will be explained diagrams basis of which correction success bezüg Lich the curvature of a scanning line on the basis of another example of each of the first and second embodiments of the invention;

FIGS. 4a and 4b are diagrams basis of which correction success of curvature bezüg Lich a scan line in an example of the third embodiment of the invention will be explained;

FIGS. 5a to 5c are explained diagrams basis of which correction success of curvature bezüg Lich a scanning line with an example of each of the fourth and fifth embodiments of the invention;

Figs. 6a and 6b are views, reference to which an embodiment of an optical scanner will be described, which has in each case an eighth to fourteenth construction according to the invention;

Fig. 7 is a view based on which a modified embodiment of the optical scanner is explained, each of which has the eighth to fourteenth structure according to the invention;

Fig. 8 is a view on the basis of which a further modified embodiment of the optical scanner, each with the eighth to fourteenth structure according to the invention, is explained;

Fig. 9 is a view on the basis of which yet another embodiment of the optical scanner, each with the eighth to fourteenth structure according to the invention, is explained;

Figures 10a and 10b are diagrams tastkenndaten a field curvature or Ab with respect to the eighth example.

FIG. 11a and 11b diagrams tastkenndaten a field curvature or Ab posted show a ninth example;

FIG. 12a and 12b are diagrams showing a field curvature or from tastkenndaten respect to show the tenth example;

FIG. 13a and 13b are diagrams showing a field curvature or from tastkenndaten respect to show an eleventh example;

FIG. 14a and 14b are diagrams showing a field curvature or from tastkenndaten respect to a twelfth example;

FIG. 15a and 15b are diagrams showing a field curvature or from tastkenndaten respect to an example 13 show;

FIG. 16a and 16b are diagrams showing a field curvature or from tastkenndaten respect to an example 14 show;

FIG. 17a and 17b are diagrams showing a field curvature or from tastkenndaten respect to show an example 15;

FIG. 18a and 18b are diagrams showing a field curvature or from tastkenndaten respect to an example 16;

FIG. 19a and 19b are diagrams showing a field curvature or from tastkenndaten respect to show an example 17;

FIG. 20a and 20b are diagrams showing a field curvature or from tastkenndaten respect to show an example 18;

FIG. 21a and 21b are diagrams showing a field curvature or from tastkenndaten respect to show an example 19;

FIG. 22a and 22b are diagrams showing a field curvature or from tastkenndaten respect to an example 20 show;

FIG. 23a and 23b are diagrams showing a field curvature or from tastkenndaten respect to show an example 21;

FIG. 24a and 24b are diagrams showing a field curvature or from tastkenndaten respect to show an example 22;

FIG. 25a and 25b are diagrams showing a field curvature or from tastkenndaten respect to show an example 23;

FIG. 26a and 26b are diagrams showing a field curvature or from tastkenndaten respect to an example 24 show;

FIG. 27a and 27b are diagrams showing a field curvature or from tastkenndaten respect to show an example 25;

FIG. 28a and 28b are diagrams showing a field curvature or from tastkenndaten respect to an example 26 show;

FIG. 29a and 29b are diagrams showing a field curvature or from tastkenndaten respect to show an example 27;

FIG. 30a and 30b are diagrams showing a field curvature or from tastkenndaten respect to an example 28 show;

FIG. 31a and 31b are diagrams showing a field curvature or from tastkenndaten respect to an example 29 show;

FIG. 32a and 32b are diagrams showing a field curvature or from tastkenndaten respect to an example 30 show;

FIG. 33a and 33b are views of an optical scanner according weils 15th to 19th embodiments of the invention according to purify it, one;

Figure 34a to 34c are diagrams respectively the 16th to explain correction success with respect to the curvature of a scan line in an embodiment of the optical scanner with up 19 assembly according to the invention.

FIG. 35a to 35c are diagrams for correction based success with respect to the curvature of a scan line is an example of the optical scanner each of the 16th and 17th from the guide of the invention to illustrate;

To correction successes of explaining Figure 36a and 36b diagrams relating to the curvature of a scanning line in an example of the optical scanner with the rule 18 design according to He-making.

FIG. 37a and 37b are views of an embodiment of an optical scanner with each rule to explain the 20th to 26th embodiments of the invention;

Fig. 38 is a view for explaining a modified embodiment of the optical scanner with reference to the 20th to 26th construction according to the invention;

Fig. 39 is a view to a further modified execution form of the optical scanner with each explaining the 20th to the 26th structure according to the invention;

Fig. 40 is a view to a further modified execution form of the optical scanner with each structure to 26 to explain the 20th according to the invention;

FIG. 41a and 41b diagrams to a field curvature and sample characteristics with respect to an example to explain 34 where in a broken line, the field curvature in a main scanning direction and a solid line toward a field curvature in a transverse thereto sampling point;

FIG. 42a and 42b diagrams showing a field curvature or from tastkenndaten respect to show an example 25;

FIG. 43a and 43b are diagrams showing a field curvature or from tastkenndaten respect to an example 36;

FIG. 44a and 44b are diagrams showing a field curvature or from tastkenndaten respect to an example 37;

FIG. 45a and 45b are diagrams showing a field curvature or from tastkenndaten respect to an example 38 show;

FIG. 46a and 46b are diagrams showing a field curvature or from tastkenndaten respect to an example 39;

FIG. 47a and 47b are diagrams showing a field curvature or from tastkenndaten respect to an example 40 show;

FIG. 48a and 48b are diagrams showing a field curvature or from tastkenndaten respect to an example 41 show;

FIG. 49a and 49b are diagrams showing a field curvature or from tastkenndaten respect to an example 42 show;

FIG. 50a and 50b are diagrams showing a field curvature or from tastkenndaten respect to an example 43 show;

FIGS. 51a and 51b are views to explain an embodiment of an optical scanner based on a 27th embodiment according to the invention;

FIG. 52 is a view showing a modified embodiment of an optical scanner be explained by a 30th embodiment according to the invention;

FIG. 53 is a view showing a further modified execution of an optical scanner with a 31 structure form according to the invention to explain;

FIG. 54 is a view showing a further modified execution form of an optical scanner with reference to a structure 34. To explain according to the invention;

FIG. 55a and 55b diagrams to a curvature of field or sample identification data with respect to an example to show 44;

FIG. 56a and 56b diagrams to a curvature of field or sample identification data with respect to an example to show 45;

FIG. 57a and 57b diagrams to a curvature of field or sample identification data with respect to an example to show 46;

FIG. 58a and 58b diagrams to a curvature of field or sample identification data with respect to an example to show 47;

FIG. 59a and 59b diagrams to a curvature of field or sample identification data with respect to an example to show 48;

FIG. 60a and 60b diagrams to a curvature of field or sample identification data with respect to an example to show 49;

FIG. 61a and 61b diagrams to a curvature of field or sample identification data with respect to an example to show 50;

FIG. 62a and 62b diagrams to a curvature of field or scanning characteristics of an example possible to show 51;

FIG. 63a and 63b diagrams to a curvature of field or sample identification data with respect to an example to show 52;

FIG. 64a and 64b diagrams to a curvature of field or sample identification data with respect to an example to show 53;

FIG. 65a and 65b diagrams to a curvature of field or sample identification data with respect to an example to show 54;

FIG. 66a and 66b diagrams to a curvature of field or sample identification data with respect to an example to show 55;

FIG. 67a and 67b diagrams to a curvature of field or sample identification data with respect to an example to show 56;

FIG. 68a and 68b diagrams to a curvature of field or sample identification data with respect to an example to show 57;

FIG. 69a and 69b diagrams to a curvature of field or sample identification data with respect to an example to show 58;

FIG. 70a and 70b diagrams to a curvature of field or sample identification data with respect to an example to show 59;

FIG. 71a and 71b diagrams to a curvature of field or sample identification data with respect to an example to show 60;

FIG. 72a and 72b diagrams to a curvature of field or sample identification data with respect to an example to show 61;

FIG. 73a and 73b diagrams to a curvature of field or sample identification data with respect to an example to show 62;

FIG. 74a and 74b diagrams to a curvature of field or sample identification data with respect to an example to show 63;

FIG. 75 is a view showing an example of the voltage optical Anord of an optical scanner according to another execution form of the invention reproduces;

76a is, which reflects to 76c are views for explaining the three systems to the optical path of the deflected light beam that has been transmitted to egg nem reflecting image forming mirrors, nen to centers of the optical path of a light beam to the image forming mirror Fig.

Fig. 77 is a view for explaining the curvature of a scan line caused by an error in the optical scan and a shift in this scan line from an ideal scan line;

Fig. 78 is an illustration for explaining a barrel-shaped ring surface which can be used as a mirror surface shape of the reflective imaging mirror;

Fig. 79 is a view for explaining an optical arrangement of the optical scanner;

Fig. 80 is a view, which are explained with reference difficulties which are pre-call by the curvature of a scanning line ago;

FIG. 81a and 81b are views about the optical arrangement of a scanner op tables for explaining an example 64;

Figure 82a to 82c are diagrams to a field curvature, Abtastkenn data to show when the optical scanner is used in an example 64, and the curvature of a scan line.

Figure 83a is a diagram showing a curvature of a scanning line when a fault in the optical arrangement of the optical scanner in the present Example 64.

Fig. 83b is a diagram showing a corrected curvature of the scan line shown in Fig. 83a;

Figure 84a to 84c are diagrams characteristics of a field curvature, the curvature of scanning or a scanning line show when the optical scanner is used in an example. 65;

Figure 85a is a diagram showing a curvature of a scanning line when a fault is present in the optical arrangement of the optical scanner in Example 65.

Fig. 85b is a diagram of a corrected curvature of the scan line shown in Fig. 85a;

Figure 86 is a view for explaining an optical scanner is an example. 66;

FIG. 87a and 87b are diagrams showing tastkenndaten a field curvature or Ab, when the optical scanner is used in an example 66;

Figure 88a is a diagram as dergibt a curvature of a scanning line when a fault in the optical arrangement of the optical scanner in the form of an example exists. 66;

Fig. 88b and 88c each a diagram showing a corrected Krüm mung the scan line illustrated in Figure 88a.

FIG. 89a and 89b diagrams showing a field curvature or from tastkenndaten reflect when the optical scanner is used in the form of an example 67;

Figure 90a is a diagram as dergibt a curvature of a scanning line when a fault in the optical arrangement of the optical scanner in the present Example 67.

Fig. 90b is a diagram of a corrected curvature of the scan line shown in Fig. 90a;

Fig. 91 is a view for the optical arrangement of an optical scanner for explaining an example 68;

Figure 92a to 92c are diagrams characteristics of a field curvature, the curvature of a scanning line or scanning wiederge ben when the optical scanner is used in Example 68.

Figure 93a is a diagram as dergibt a curvature of a scanning line when a fault is present in the optical arrangement of the optical scanner in Example 68.

Fig. 93b is a diagram of a corrected curvature of the scan line shown in Fig. 93a;

Fig. 94 a modified embodiment of the optical scanner in the example 68;

Fig. 95 is a view for the optical arrangement of an optical scanner for explaining an example 69;

Fig. 96 is a view of a modified embodiment of the optical scanner is an example of rule 69;

Figure 97a to 97c are diagrams characteristics of a field curvature, the curvature of a scanning line or scanning wiederge ben when the optical scanner is used in the form of an example. 69;

Figure 98a is a diagram as dergibt a curvature of a scanning line when a fault in the optical arrangement of the optical scanner in the form of Example exists. 69;

FIG. 98b is a diagram of a corrected curvature of the scan line shown in FIG. 98a;

Fig. 99 is a view of the entire arrangement of an optical scanner op tables in the form of Example 69;

To explain Fig 100 is a view for the optical arrangement of an optical scanner with reference to an example. 70;

Fig 101a to 101c diagrams tastkenndaten a field curvature, or from the curvature of a scanning line as dergeben when the optical scanner is used in the form of a case of the game. 70;

Figure 102a is a graph showing the curvature of a scanning line when a fault is present in the optical arrangement of the optical scanner in Example 70.

FIG. 102b is a diagram of a corrected curvature of the scan line shown in FIG. 102a, and

FIG. 103 is a view of the entire arrangement of an optical scanner op tables in Example 70.

The invention is based on preferred embodiments Forms of an optical scanner according to the invention of the accompanying drawings.

In an optical scanner according to the invention, a light beam from a light source deflected by a deflector steers, which has a reflective deflection surface, which with egg rotated at a steady speed, and strikes a reflective imaging element. The one on the picture The reflected light beam is reflected by an image generation process of the reflective imaging element as a point of light converges on a surface to be scanned. Of the optical scanners essentially perform an optical scan process at a constant speed. How As mentioned above, the deflector directs the light beam from. The deflection device is shaped by a pyramid  Mirror, a cylindrical mirror, a rotating poly gon mirror, etc. formed.

In a first embodiment of an optical scanner according to the Invention, the deflection device has a reflective deflection surface that is rotated at a uniform speed. A Light beam from the light source is through the deflector with a uniform angular velocity on one level distracted and hitting a semi-transparent mirror, wel cher is inclined with respect to a beam deflection surface on a re reflective imaging element. The one on the imaging Element reflected light beam is on the semi-transparent Reflected and by an image generation process of the Imaging element as a point of light on one to scan converges to an optical scan through the area respectively. The reflective imaging element has the radio tion, essentially the optical scanning process using the Perform light point at a uniform speed ren. The reflective imaging member is arranged that it is in a direction perpendicular to the beam deflecting surface is shifted by a predetermined value, the curvature correct a scan line on the scanned surface.

As mentioned above, in the optical scanner according to the Invention the deflection device for deflecting the light beam the reflective deflecting surface with a uniform speed is rotated. The beam of light from the light source will reflected on the deflection surface and abge by its rotation directs. A beam deflection surface is in the present invention defined as follows.

The beam deflection surface is brought into one plane, the one Incident reference position passes through and perpendicular to a Dre axis of the reflective deflection surface. The resourcefulness position is in an incident position of a main beam of the  Bring light beam, which on the reflective deflecting surface surface in a state in which the height of an image of the point of light or spot, which is on the scanned Area has converged, zero is set. The axis of rotation of the right flexing deflection surface is an ideal axis of rotation, at wel axial vibration, etc. is not taken into account. The Displacement of the reflective imaging element is as a distance from an intersection of an optical axis and a reflective surface of the imaging member the beam deflection surface. This intersection is a Center of the reflective imaging element.

In an optical scanner according to a second embodiment of the Invention has a deflector a reflective deflector area that rotated at a uniform speed becomes. A beam of light from a light source is passed through the Ab steering device with a constant angular velocity distracted at one level and hitting a semi-permeable one Mirror which is inclined with respect to the beam deflection surface, on a reflective imaging member. The one on the bil the generating element reflected light beam is on the half translucent mirror and reflected by a picture on the imaging element as a light spot a surface to be scanned converges, creating an optical Scanning is performed. The reflective image supply element has a function to essentially the optical Scanning process with the help of the light point at a constant to perform the speed. The imaging element is arranged so that its optical axis about a predetermined th tilt angle with respect to the beam deflection surface is inclined to thereby the curvature of a scan line on the scanned area to correct. The tilt angle is set to an angle which is between the optical axis of the imaging elements and the beam deflecting surface is formed as above is already mentioned.  

In the optical scanner, which is the first or second version the semi-transparent mirror can be a semi-transparent one Have a mirror surface on one side. Furthermore, the semi-trans Parent mirror surface through transparent, flat, parallel surfaces be worn on both sides.

In a third embodiment of an optical scanner according to the Invention has a deflector a reflective deflector area that rotated at a uniform speed becomes. A beam of light from a light source is passed through the Ab steering device at a uniform angular velocity distracted to one level and hits over a semi-permeable one Mirror which is inclined with respect to a beam deflection surface, on a reflective imaging member. The one from the bil the generating element reflected light beam is on the half translucent mirror reflected and generated by an image effect of the imaging element as a point of light on one area to be scanned converges, creating an optical scan is carried out. The reflective imaging element has the function, essentially using the optical scanning process Help the light spot at a steady speed perform. The semi-transparent mirror has a semi-trans Parent mirror surface on one side of the deflection device.

In a fourth embodiment according to the invention that is right reflective imaging element of the third embodiment ordered that there is a predetermined amount of displacement in shifted in a direction perpendicular to the beam deflection surface is used to measure the curvature of a scan line on the Correct area. In a fifth version of the Erfin the reflective imaging element is arranged so that an optical axis of the reflective imaging element ment with respect to the beam deflection area by a predetermined one Tilt angle is inclined to the curvature of a scan line  correct the scanned area.

In a sixth embodiment according to the invention that is right reflective imaging element of the second or fifth Aus guide arranged so that its optical axis with respect to Beam deflection surface inclined by the predetermined tilt angle and the imaging member by a predetermined one Displacement in a perpendicular to the beam deflection surface Direction is shifted to the curvature of the scan line correct the scanned area. The curvature of the scan line can generally be corrected by the fact that the reflective imaging element with respect to the beam deflecting surface inclined and ver with respect to the beam deflecting surface is pushed.

In a seventh embodiment according to the invention, the right flexing deflection surface of the deflection device parallel to the sen axis of rotation in the first to sixth versions of the Invention arranged. By means of the reflective image Position elements of the reflective deflection surface and the scanned area in a conjugate relationship in correspond to the geometric optics in a cross-scan direction set. The beam of light from the Lichtquel le is focused and as one in one of the main scanning directions linear image nearby in the corresponding direction the reflective deflecting surface in a cross-scanning direction corresponding direction generated. The ent of the cross-scan direction speaking direction is set in a direction which corresponds to a transverse scanning direction and parallel to it runs a virtual light path, which thereby creates is that a light path from the light source to the scanned Surface is formed linearly along an optical axis. The direction corresponding to the main scanning direction becomes in a Direction set that a main scanning direction on the front corresponds to the virtual light path mentioned and parallel to this  runs.

In an eighth version of an optical scanner according to the Invention has a deflector a reflective deflector surface that is rotated at a uniform speed. A Beam of light from a light source is passed through the deflector tion with a uniform angular velocity in one Level distracted and anamorphic, reflective Image element reflected. The reflected light beam is through an imaging effect of the reflected imaging element converts as a point of light on a scanned surface giert, whereby an optical scanning is carried out. The right inflected imaging element has the function, in essence Chen the optical scanning process with the help of the light point to perform at a constant speed. A transparent, flat parallel plate is between the deflection direction and the imaging device arranged in the manner net that the flat parallel plate under a finite Nei tion angle with respect to an axis of rotation of the deflection device tends. The flat parallel plate separates a light path from the deflector to the imaging member from one Light path from the imaging element to a scanned one Area. Material, thickness and angle of inclination of the plane parallel Plate are set so that the curvature of a scan line is corrected. This angle of inclination is an angle which between mutually parallel surfaces of the plane parallel ones Plate and a direction of the axis of rotation of the deflector is trained. Permeability with the flat parallel plat te means that the plane parallel plate with respect to the light beam is transparent, which is for the optical scanning process is used. Consequently there is no permeability of the flat parallel plate with respect to light in all wavelength ranges required.

In a ninth embodiment according to the invention, the  directed light beam which is directed onto the reflecting image tion element strikes, and that of the imaging element reflected light beam in the eighth version from the ebe NEN parallel plate allowed. With a tenth execution tion according to the invention, only the deflected light beam, which on the reflected imaging element of the eighth Execution hits from the flat parallel plate Lich of the deflected light beam that is reflected on the Imaging element strikes and transmitted through the light beam sen which has been reflected on the imaging member is.

In an eleventh embodiment according to the invention, the Nei angle of the flat parallel plate of the eighth to tenth version set so that an angle of incidence from directed light beam that is directed onto the flat parallel plate hits, is set appropriately to approach a brew enough angles.

In the aforementioned embodiment according to the invention both the deflected and the reflected light beam passed through the flat parallel plate. In this Case is a re according to a twelfth embodiment of the invention reflective thin layer on a flat part of the flat pa parallel plate on the side of the deflector of the ninth Execution applied so that only the light beam from the Imaging element reflected and from the plane parallel Plate has been let through selectively on the thin layer is reflected.

According to the tenth embodiment of the invention, the on the Imaging element reflected light beam on the scanned th area as it is. According to a 13th off The invention is based on a reflective thin layer a surface part of the flat parallel plate on the side of the  reflective imaging element of the tenth embodiment formed so that only the reflector on the imaging element The light beam is selectively right on the reflective layer is inflected.

In a fourteenth embodiment of the invention, the reflec ting deflection surface of the deflection device parallel to the Rotation axis for the eighth to thirteenth versions. Of the Light beam from the light source is focused and as a li near image corresponding to one of the main scanning direction Direction is near the reflective baffle generated. Approximately Po sitions of the reflective deflection surface and the scanned Area in a converged relationship in a geometric Optics with respect to a cross-scanning direction Direction set.

In a 15th version of an optical scanner according to the Er is a beam of light from a light source by means of a Deflector at a uniform angular velocity deflected on one level and right on an imaging element inflected. The reflected light beam is by means of a bil the process of forming the imaging element as a light point converges on a surface to be scanned, causing a optical scanning is performed. That reflective pictures generating element has the function, essentially the optical Scanning with the help of the light point at a constant Speed. An elongated prism has in the Cross section of a wedge shape and is parallel to one of the main sections direction corresponding to the scanning direction between the deflecting device device and the imaging element. The langge stretched prism separates a light path from the deflection device to the reflective imaging element from a light path from the imaging element to the scanned surface.  

In this case, according to a 16th embodiment of the invention reflective imaging member arranged to be a predetermined path of travel in one beam steering surface is shifted in the vertical direction, so the elbow correct a scan line. On the other hand, according to a seventeenth embodiment of the invention supply element arranged so that its optical axis under egg a predetermined tilt angle with respect to a beam deflection is inclined, so the curvature of a scan line on the correct the area to be scanned. According to an eighteenth Implementation of the invention is a reflective surface of the bil derzeugungselements the sixteenth embodiment by a coaxial all spherical or aspherical surface formed.

According to a nineteenth embodiment of the invention, Ab steering device reflect a parallel to its axis of rotation de deflection surface in the fifteenth to seventeenth offs guide. The reflective imaging element is anamorphic table and represents positions of the reflected deflection surface of the Deflection device and the scanned area in a konju ing relationship in geometric optics in one of the cross direction corresponding to the scanning direction. The beam of light from the light source is focused and as a linear image that runs in the direction corresponding to the main scanning direction, generated near the reflective baffle.

According to a twentieth version of an optical scanner of the invention, a deflector has a reflective one Deflection surface that ge at a uniform speed is turning. A beam of light from a light source is transmitted through the Deflection device with a constant angular velocity distracted and anamorphic, reflective Imaging element reflected. The reflected beam of light is performed by an image forming process of the image forming element converts as a point of light on a scanned surface  giert, whereby an optical scanning is carried out. The right flexing imaging element has the function essentially Lichen the optical scanning with the help of the light point constant speed. A transparent one te, flat, parallel plate is between the deflector and the imaging element arranged so that the plane pa parallel plate at a finite angle of inclination with respect an axis of rotation of the deflection device is inclined. The level pa parallel plate separates a light path from the deflection device to the imaging device from a light path from the Imaging device to a scanned surface. The right reflective imaging element is under one agreed tilt angles inclined with respect to a beam deflection surface. Material, thickness and angle of inclination of the flat parallel plate and the tilt angle of the imaging member with respect to Beam deflection surface are set so that the curvature of a Scan line is corrected.

In a 21st embodiment of the invention, the reflected Light beam striking the imaging element and the light beam reflected from the imaging element the flat parallel plate of the 20th embodiment. In a 22nd embodiment of the invention, only the distracted one Light beam directed onto the imaging element of the 20th embodiment strikes, from the flat parallel plate with respect to the deflected light beam that is applied to the imaging element strikes, and let the light beam pass through the pictures generating element has been reflected.

In a 23rd embodiment of the invention, the angle of inclination the flat parallel plate in the 20th to 22nd versions set so that an angle of incidence of the reflected light beam that strikes the flat parallel plate, so inserted is that it approximately corresponds to a Brewster angle.  

In the 21st version, the on the imaging element incident light beam and that on the imaging element reflected light beam from the flat parallel plate through calmly. According to a 24th embodiment of the invention, a right reflective thin layer in a flat part of the flat pa parallel plate on one side of the deflection device of the 21st Execution so applied that only the light on the pictures generating element reflected and from the flat parallel plate has been transmitted selectively at the reflective Layer is reflected. According to the 22nd version, the on light beam reflected from the imaging member as he is directed to the area to be scanned. According to a 25th off leadership of the invention, however, is a reflective thin Layer in a surface part of the flat parallel plate the side of the reflective imaging member of Fig. 22. Execution generated so that only that on the imaging element reflected light beam selectively on the reflective layer is reflected.

According to a 26th embodiment of the invention, the reflec ting deflection surface of the deflection device parallel to the Rotation axis in the 20th to 25th versions. The beam of light is focused by the light source and as a linear image, that in a direction corresponding to the main scanning direction runs, generated in the vicinity of the reflective deflection surface. Approximately positions of the reflective deflection surface and the scanned surface in egg a conjugate relationship in a geometric look Lich set the direction corresponding to the cross-scan direction.

In the optical scanner, each with the structure according to which he Most until the 26th version, the light beam is deflected device distracted on one level. An area that through a main beam of the light beam which is deflected  direction has been deflected is a plane that descends is right to the axis of rotation of the reflective deflecting surface. This area corresponds to the beam deflection area.

According to an optical scanner, which the 27th to 35th Has execution according to the invention, a light beam from the Light source deflected by a deflection device, the right reflective deflection surface with a uniform speed is rotated and is shown on an anamorphic picture reflected element. The reflected light beam will by an image forming process of the reflective image supply element as a point of light on a scanned surface converges, thereby performing optical scanning. The reflective imaging element has a function to essentially optical scanning using light beam at a uniform speed.

According to the 27th embodiment of the invention, a transparent, flat parallel plate between the deflector and the Imaging element arranged so that the flat parallel plate te at a finite angle of inclination with respect to a rotary axis se the deflector is inclined. The one on the reflective Deflection surface of the deflecting light beam is adjusted so that it is inclined on a beam deflecting surface meets. The flat parallel plate separates a light path from the Deflector to the imaging element from a light away from the imaging member to the scanned surface. Material, thickness and angle of inclination of the flat parallel plate and a shift amount of the deflected light beam with respect to the Imaging elements are set so that the curvature a scan line is corrected.

An intersection of the reflective surface of the imaging elements and its optical axis is in a middle part of the reflective imaging member. If the  Height of an image of the point of light on the scanned surface is zero, the light beam shift amount is ei the distance between this middle part and a position, on which a main beam of the deflected light beam onto the the aforementioned reflecting surface hits.

According to the 28th embodiment of the invention, a transparent, flat parallel plate between the deflector and the Imaging element arranged so that the flat parallel plate te at a finite angle of inclination with respect to a rotary axis se the deflector is inclined. The one on the reflective Surface of the deflecting light beam is so set that this light beam obliquely on a beam steering surface meets. The flat parallel plate separates you Light path from the deflector to the imaging element from a light path from the imaging element to the target constant surface. The imaging element is arranged so that its optical axis at a predetermined tilt angle is inclined with respect to a beam deflection surface. Material, thickness and tilt angle of the flat parallel plate and the tilt angle of the imaging member are set so that the curvature a scan line is corrected.

According to the 29th embodiment of the invention, this is reflective Imaging element of the 27th embodiment arranged so that a optical axis of the imaging element under a pre agreed tilt angles inclined with respect to the beam inclination surface is. Material, thickness and angle of inclination of the flat parallel plate te, the beam shift size and the tilt angle of the Imaging elements are set so that the curvature the scan line is corrected.

According to the 30th embodiment of the invention, that in the picture generating element incident deflected light beam and the the imaging element reflected light beam from the plane  NEN parallel plate each of the 27th to 29th embodiment let through. On the other hand, according to the 31st embodiment of the Invention only of the image element deflected light beam with respect to the flat parallel plate the deflected one striking the imaging element Light beam and that reflected on the imaging element Light beam let through. According to the 32nd version of the Erfin is the angle of inclination of the flat parallel plate in each case of the 27th to 31st embodiments so that an idea angle of the deflection striking the flat parallel plate ten light is set so that approximately a Brewster win is enough.

According to the 33rd embodiment of the invention is a reflective thin layer in a flat part of the flat parallel plate the side of the deflector of the 30th embodiment so trained det that only the light beam that is on the imaging element reflected and let through from the flat parallel plate, is selectively reflected on the reflective layer. According to the 34th embodiment of the invention becomes a reflective Layer on a surface part of the flat parallel plate on the Side of the reflective imaging member of the 31st embodiment tion formed so that only on the imaging element reflected light beam selectively on the reflective layer is reflected.

According to the 35th embodiment of the invention, the reflective Surface of the deflection device parallel to its axis of rotation in the 27th to 34th embodiment. The light beam from the light source is focused and as a linear image that is in one of the Main scanning direction corresponding direction runs in the Nä he formed the reflective deflector. Through the picture generating element will approximately reflect positions of the the deflection surface and the scanned surface in a conjugate th relationship in a geometric optic with respect to one of the  Cross scan direction set direction.

In the 27th to 35th embodiments of the invention, light hits beam onto the beam deflecting surface at an angle. Hence is too this time an area, which by means of a main ray of the ideally deflected light beam has been scanned, a ge curved surface, similar to a conical surface.

The reflective imaging member is arranged so that whose optical axis coincides with the beam deflection surface. The semi-transparent mirror is between the deflection device and the imaging member so that the halfway casual mirror is inclined with respect to the beam deflection surface. In In this case, the deflected light beam, which is from the semitransparent mirror has been let through in a too the vertical direction of the beam deflection, because the semi-transparent mirror has a certain thickness. Consequently a point of impact of the deflected light beam which is directed onto the Imaging element strikes away from the optical axis shifted so that the locus of a point of light is curved.

In the optical scanner, one of the first to seventh off leadership forms, as described in each case later are shown, the imaging element is in one shifted perpendicular to the beam deflection surface. On otherwise the optical axis of the imaging element is inclined with respect to the beam deflection surface. Furthermore, the half translucent mirrors can be arranged so that its semi-trans Parent mirror surface on the side of the deflection device is arranged. Consequently, the curvature of the scan line can be considered that Locus curve of the light point can be effectively corrected.

In the optical scanner, the eighth to fourteenth Embodiment has, the flat parallel plate between the deflector and the imaging element.  

At least the light beam deflected by the deflection device is let through by the flat parallel plate before the right reflected light beam strikes the imaging element. As in each of the embodiments described later is, the curvature of a scan line can effectively correct be gier by the material and thickness of the flat parallel plate and their angle of inclination with respect to the axis of rotation of the deflection direction can be set.

For the 15th version of the optical scanner, that's long stretched prism between the deflector and the image generating element arranged. The direction of the distracted The light beam is refracted with respect to the beam deflecting surface che inclined. Hence are an incident direction of light beam striking the imaging member and one Reflection direction of the reflecting on the imaging element th light beam inclined with respect to the beam deflecting surface. Consequently can light paths of these light beams ge from each other be separated. In the 16th to 19th version of the optical scan Ners is Darge, as in each of the examples described later is, the reflected picture element in one to the beam deflecting surface shifted in the vertical direction. Otherwise it will the optical axis of the imaging member with respect to Beam deflection surface inclined. Consequently, the curvature of an Ab Effective correction of the tracing line as the locus of a light point become.

The 20th to 26th version of the optical scanner is the flat parallel plate between the deflector and the right arranged reflective imaging element. At least that light beam deflected by the deflection device is emitted by the flat parallel plate passed before the deflected light beam strikes the reflective imaging member. Furthermore, this imaging element is beam-off steering surface inclined. As in each version described later  tion forms, the curvature of a scan line be effectively corrected that the material and thickness of the flat parallel plate, the angle of inclination with respect to the Dre axis of the deflection device and a tilt angle of the reflective th imaging element with respect to the beam deflection surface be put.

In each of the 27th to 35th versions of the optical scanner the flat parallel plate between the deflector and the reflective imaging element arranged. At least that light beam deflected by the deflection device is from the flat parallel plate passed before the deflected light beam strikes the reflective imaging member. Furthermore, the one that strikes the reflective deflection surface Light beam inclined with respect to the beam deflection surface.

The amount of displacement of the deflected light beam with respect to the Imaging element and / or the tilt angle of the image supply element is together with the material and the thickness of the flat parallel plate and its angle of inclination with respect to Rotation axis of the deflection direction set. Consequently, the Curvature of a scan line can be corrected effectively.

Furthermore, in each of the seventh, fourteenth, nineteenth, twenty-sixth and thirty-fifth embodiment of the optical scanner, the deflection device to its axis of rotation parallel, reflective deflection surface. The beam of light from the Light source is focused and by means of this deflection device as a linear image in the main scanning direction speaking direction, near the reflective Deflection surface created. Furthermore, by the imaging element ment positions of the scanned surface and the reflective Area of the deflector in a conjugate relationship in geometric optics with respect to the cross-scanning direction appropriate direction set. Consequently, a Nei  correction of the reflective deflection surface. How from each of the examples can be seen, the shifting and tilt values of the reflective imaging member are small. Consequently, the position of the reflective surface of the Ab steering device and the position of the scanned surface the reflective imaging element in the conjugate Be drawing with respect to the cross-scan direction Direction can be set with high accuracy.

If the relationship between the light source and the distraction is no direction is improved, the inclination of the reflective Deflection surface can be corrected even if the deflection is not direction formed by a pyramid-shaped mirror, etc. is, and the reflective deflector at 45 ° with respect to Axis of rotation is inclined.

An optical scanner in another embodiment of the Er invention has a light source unit, a linear, picture ing optical system, an optical deflector, a Spot or spot producing optical system and one Adjustment mechanism. The light source unit emits a light beam for performing optical scanning. The light source unit is through a light source, such as a semiconductor laser, a light emitting diode, etc. are formed. Otherwise it is the light source device by this light source and a Coupling lens formed.

The linear, imaging, optical system focuses and he creates the light beam from the light source unit as a linea res image corresponding to one of the main scanning direction Direction runs. The linear, imaging, optical system can by an optical system with a positive refractive power only in a direction corresponding to the cross-scanning direction be formed. This optical system consists of one to be described later, a cylindrical lens  mirror, etc. together. The linear, imaging, opti cal system can be designed so that this optical system also correspond to a refractive power in the main scanning direction has the direction.

The direction corresponding to the main scanning direction is set to ei ne direction set parallel to a main scan direction runs and the main scanning direction on a virtual len corresponds to light path, which by linear formation of a Light path from the light source to a scanned area has been held. The one corresponding to the cross-scan direction Direction is set to a direction parallel to egg ner cross-scan direction and this cross-scan direction on this virtual light path.

The optical deflector reflects the light beam from the left near, imaging, optical system on a reflect de deflecting surface and directs the light beam with a uniformi towards angular velocity. This deflection of the light beam at the uniform angular velocity means that the deflected light beam is projected onto a surface that perpendicular to an axis of rotation of the reflective deflection surface is, and this projected light beam becomes the same at one shaped angular velocity deflected. In the following Be writing becomes a distracting scanning surface on a virtual one Level set by means of a main ray of light beam is scanned by means of the optical deflector has been ideally distracted.

The optical system generating the light point directs the abge directed light beam onto the scanned surface and converged the deflected light beam as a point or spot of light the scanned area. This optical system can be form different types of optical elements that are connected to egg A light path from the optical deflector to the one to be scanned  Surface are arranged. This optical system has a bil generating reflective mirror, which is the function has the deflected light beam onto the scanned surface in at least the direction corresponding to the main scanning direction converge and the optical scanning process with an equal shaped speed.

This optical system can be an elongated cylindrical lens and an elongated toroidal lens in addition to that have imaging, reflecting mirrors. Otherwise the optical system can have an elongated, concave mirror which is equivalent to the elongated cylindrical lens or the elongated toroidal lens. The langge stretched cylindrical lens, the elongated toroidal lens or the elongated concave mirror are near the ab keyed area arranged to a field curvature in the Correct cross-scan direction. Furthermore, the optical Sy stem different types of optical ele have a light path of the deflected light of one that strikes the imaging mirror Light path of the deflected, reflecting on the imaging mirror based light beam according to the 46th and 48th versions of the previous separate invention.

The adjustment mechanism is provided to adjust the curvature of a Correct scan line. According to a 36th version of the Er the adjusting mechanism provides the rotary movement of the bil the generation mirror around an axis that is parallel to the steering scanning surface and perpendicular to an optical axis runs. With this setting, an angle of inclination of the Imaging mirror with respect to the deflecting scan surface in that the imaging angle by the previous imagined axis in the normal and reverse direction is turning.  

In a 37th embodiment of the invention, the adjusting mechanism a movement of the imaging mirror in one to the other deflecting scanning surface in a vertical direction. In a 38th Implementation of the invention provides the adjustment mechanism Rotation of an imaging mirror about an axis, which is parallel to the deflecting scanning surface and perpendicular to the optical axis. The adjustment mechanism provides also the movement of the imaging mirror in one to that deflecting scanning surface in a vertical direction.

In a 39th embodiment of the invention, the imaging mirrors in the 36th, 37th or 38th version an aspherical right reflecting mirror surface. In a 44th version of the Erfin is the light source in a corresponding manner by a Semiconductor laser trained.

In a 40th embodiment of the invention, a position of the linear, imaging, optical system set to a Inclination of the reflective deflecting surface of the optical deflector tors so that the linear image that is in one of the Main scanning direction corresponding direction runs in the Nä he the reflective surface of the optical deflector becomes. Furthermore, this optical system is designed so that it 99999 00070 552 001000280000000200012000285919988800040 0002004401731 00004 99880 approximate positions of the reflective baffle and the scanned area in a conjugate relationship in a geometric optics with respect to the cross-scan direction ent speaking direction.

In a 41st embodiment of the invention, he has the light points optical system generating a reflecting mirror, which is rotatable about an axis which is parallel to that of the main section Direction corresponding to the scanning direction.

If the reflecting surface of the imaging mirror is one is aspherical surface, this reflective surface can pass through  a coaxial aspherical surface in a 42nd version of the Invention are carried out. In a 46th version of the Erfin is the reflecting mirror, which is the aspherical Surface has an anamorphic, concave mirror with various imaging functions in the main direction corresponding to the scanning direction and in the cross-scanning direction corresponding direction executed. This anamorphic The concave mirror is used as an aspherical surface.

In a 43rd embodiment of the invention, the light beam that hits the reflective surface of the optical De from the light source unit in the 36th to 38th embodiment hits as a divergent light beam in the direction corresponding to the main scanning direction. In a 45th embodiment of the invention, this light beam set as a convergent light beam. In a 53rd out leadership of the invention is this light beam as an approximation parallel light beam set.

As mentioned above, the op table system have an optical element to light paths of to separate each other. This optical element is between the optical deflector and the imaging mirror arranged to the light beam deflected by the optical deflector to separate the light beam that re on the imaging mirror has been inflected.

In a 47th embodiment of the invention is the optical element for a light path separation in the 36th version by a semi-translucent mirror or a glass plate that runs partially has a mirror surface created by vapor deposition. In the 48th embodiment of the invention is this optical separator ment formed by a prism. In a 52nd version of the Er is the optical separating element as a transparent, flat parallel plate executed, which obliquely with respect to the deflect  kenden scanning surface is arranged.

In a 49th embodiment of the invention, the optical scanner in the 37th version also an optical element for correcting the inclination of the reflective surface of the optical deflector tors. The adjustment mechanism can move this the Nei corrective optical element in the same direction how to adjust the imaging mirror. In this case, a 50th embodiment of the invention of the adjustment mechanism Movement of the optical element correcting the tilt and un depending on the imaging mirror. In a 51st The embodiment of the invention is the optical deflector in FIG. 50. Design accordingly as a rotating polygon mirror, a pyramid-shaped mirror or a rotating, single-surface Mirror trained.

FIG. 1a schematically illustrates only a main part of an example of an optical scanner in which can be applied to the seventh embodiments of the invention each of the first. In Fig. 1a, a light source 1 is implemented by a laser diode (LD), a light emitting diode (LED), etc. A light beam is emitted from the light source 1 , and a lens 2 with a positive refractive power prevents this light beam from diverging. If the light beam is transmitted through this lens 2 , the light beam is converted into a parallel light beam, a convergent light beam and a divergent light beam. The light beam is then converged by a cylindrical lens only in a direction corresponding to the cross-scanning direction. The light beam is focused and produced as a linear image that extends in a direction corresponding to the main scanning direction in the vicinity of a reflecting surface of a deflector 4 .

The deflection device 4 is formed by a cylindrical or pin-shaped (tenon type) mirror, in which a so-called pin is formed in an upper part of a rotary shaft of this mirror. An area of the pin parallel to an axis of rotation of this mirror is set as a reflective deflecting surface. The rotating shaft of this mirror is rotated by a motor. The light beam from the light source 1 is adjusted so that a main beam of this light beam strikes the reflecting deflecting surface in a plane that is perpendicular to the axis of rotation of the deflecting device 4 . Consequently, a surface which has been scanned by means of the main beam of the light beam deflected by the deflecting device 4 at a uniform angular velocity coincides with a beam deflecting surface which is perpendicular to the aforementioned rotary axis.

The light beam, which has been deflected by the deflection device 4 at a uniform angular velocity, is passed through a semi-transparent mirror 5 and then strikes a reflective imaging element 6 in the form of a concave mirror. When the deflected light beam is reflected on a reflective imaging member 6 , the deflected light beam is reflected on the semitransparent mirror 5 and strikes a surface of a recording medium. The incident light beam is converged by an imaging process of the reflective imaging member 6 as a light spot on a peripheral surface of the recording medium 7 . An optical scanning process using the light spot is ideally carried out on an optical scanning line 1 in accordance with a deflection of the deflected light beam. Consequently, a scanning line of the light spot ideally coincides with the optical scanning line L. In fact, however, the scanning line of the light spot is curved or curved and shifted with respect to the optical scanning line L. A scanned area in the invention has this optical scanning line L in a tangential plane on the peripheral surface of the recording medium 7 .

The reflective imaging member 6 has the function of converging the deflected light beam as a light spot on the scanned surface. The Bilderzeugungsele element 6 also has the function of essentially performing the optical scanning with the aid of the light spot at a uniform speed. This function is fully performed so that an error in the optical scanning which has been shifted with respect to the scanning operation carried out at a uniform speed by means of the light spot can be corrected by electrical processing signals. As mentioned above, a light beam incident on the deflector 4 is formed as a linear image which extends in the direction corresponding to the main scanning direction in the vicinity of the reflecting deflecting surface. Accordingly, positions of the reflective deflecting surface and the scanned surface are set by the reflective imaging member 7 in a conjugate relationship in a geometric optic in the direction corresponding to the cross-scanning direction. Normally, imaging functions of the reflective imaging member in the direction corresponding to the main scanning direction and the direction corresponding to the transverse scanning direction are different from each other, so that the reflecting imaging member 7 is anamorphic. The reflective imaging member 8 has a mirror surface shape which is generated as follows. The mirror surface of the reflective imaging member 6 has a shape which is represented by the following general formula on a surface defined by an optical axis of the reflective imaging member as a symmetrical axis of the mirror surface and also by a straight line perpendicular to the same optical axis and parallel to the direction corresponding to the main scanning direction:

Y ² -2 R _m X- (K + 1) X ²

In this formula, X denotes a coordinate in a direction of the optical axis and Y denotes a coordinate in a direction perpendicular to the optical axis with a position on the optical axis as the zero point. Furthermore, R _m denotes a radius of curvature of the mirror surface on the optical axis and K denotes a conical constant. The above-mentioned plane defined by the optical axis of the reflective imaging member and the straight line is referred to as a main symmetrical surface in the following description. A three-dimensional shape of the mirror surface is formed as a concave barrel-shaped surface by rotating the shape represented by the above formula in a state in which an axis disposed at a distance R _S from the mirror surface on the optical axis and perpendicular runs to the axis in the main symmetry surface, is set on an axis of rotation of the mirror surface. Consequently, the shape of the mirror surface of the reflective imaging element 6 is determined by three parameters R _m , R _S and K. The mirror surface of the reflective imaging member has a shape which is represented by the above formula. Such content means that the shape of the mirror surface is essentially represented by the general formula given above.

Fig. 1b schematically shows a main part of the optical scanner in an embodiment in which the first embodiment of the invention is used in the optical scanner shown in Fig. 1a. A beam deflection surface BS coincides with a virtual plane, which is formed by the scanning process being carried out with the aid of a main beam of the light beam, which is ideally deflected by the deflection device 4 .

The semi-transparent mirror 5 is between the deflection device 4 and the reflective imaging element 6 angeord net. A surface 5 b of the mirror 5 on the side of the imaging element 6 is formed by a semi-transparent mirror surface and is inclined with respect to the beam deflection surface BS. The deflected light beam is passed through the semi-transparent mirror 5 and reflected on the reflective imaging element 6 . The deflected light beam is then reflected on the semi-transparent mirror surface, which is formed as the surface 5 b of the mirror 5 and is converged as a light spot or spot on the recording element 7 .

In the embodiment shown in FIG. 1b, an optical axis AX of the imaging element 6 runs parallel to the beam deflection surface BS. The entire, reflective imaging element 6 is shifted by a shift amount ΔZ in a surface perpendicular to the image deflection surface BS. Since the optical axis AX of the imaging element 6 is parallel to the beam deflection surface in this case, the shift amount ΔZ is a shift amount of the optical axis AX with respect to the beam deflection surface BS and is set to be on an upper side of the beam deflection surface BS in FIG. 1b is positive (+).

For example, the aforementioned three parameters, which determine the shape of the mirror surface of the reflective imaging element 6 , are: R _m = -277 mm, R _S = -91 mm and K = -0.33. Furthermore, the semi-transparent mirror 5 has a refractive index n = 1.51118 and a thickness t = 7 mm. The mirror 5 is inclined at an inclination angle α = 45 ° with respect to the beam deflection surface BS. This angle of inclination α is equal to an angle which is formed between the normal to a mirror surface 5 a, which is parallel to the mirror surface 5 b, and the beam deflection surface BS. A distance L ₀ from the reflective deflection surface 4 a to the imaging element 6 is set to 87.42 mm, and an optical scanning width S is set to 216 mm.

In this case, when the shift amount ΔZ of the image forming member 6 is set to zero, the curvature of a scanning line caused by the light spot is formed as shown in Fig. 2a. There is usually no difficulty because of the curvature of the scan line near a central portion of an optical scan area. However, the scanning line is strongly curved at both end parts of the optical scanning area, so that this curvature prevents a corresponding optical scanning.

example 1

The semitransparent mirror and reflective imaging member mentioned above are used. As shown in Fig. 1b, the image forming member 6 is arranged in a state in which it ( 6 ) is shifted ver by the displacement amount ΔZ in a direction perpendicular to the beam deflecting surface BS. If the shift amount ΔZ is set to -0.36 mm, the curvature of a scan line is reduced and set so that it is relatively small in the entire optical range, as shown in Fig. 2b, so that this curvature of the scan line is excellently corrected.

Fig. 1c schematically shows only a main part of the optical scanner in an embodiment in which the second embodiment of the invention is used in the optical scanner shown in Fig. 1a. An intersection of the mirror surface and the optical axis AX of the reflective imaging element 6 is set on the beam deflecting surface BS. The optical axis AX of the imaging element 6 is inclined by a tilt or inclination angle ΔR with respect to the beam deflection surface BS. This tilt angle ΔR is set to be positive (+) when the mirror surface of the image forming member 6 is rotated clockwise.

Example 2

The semitransparent mirror and the reflective imaging member are the same as those in Example 1. In Example 2, the inclination angle is α = 45 °, the distance L ₀ = 87.42 mm, and the optical scanning width S = 216 mm. The tilt angle ΔR of the imaging element 6 is set to -0.22 °. In this case, the curvature of a scan line is obtained, as shown in Fig. 2c. Consequently, similarly to Example 1, the curvature of the scan line is excellently corrected. The above three parameters which define the shape of the mirror surface of the reflective imaging member 6 are set to R _m = -218.6 mm, R _S = -109.4 mm and K = - 1.89. Furthermore, the semi-transparent mirror 5 has a refractive index n = 1.51118 and a thickness t = 8.4 mm. The mirror 5 is inclined at an angle of inclination α = 56 ° with respect to the beam deflection surface BS. From the stand L ₀ from the reflective deflection surface 4 a to the imaging element is 66.1 mm and the optical scanning width S is set to 216 mm.

In this case, when the shift amount ΔZ of the imaging member 6 from the beam deflecting surface BS is set to zero and the tilt angle ΔR is also set to zero, a scanning line of the light spot is curved as shown in Fig. 3a. The scanning line is strongly curved from an area near a central part of an optical scanning area to both end parts of the optical scanning area, so that this curvature prevents a corresponding optical scanning process.

Example 3

Under the above assumption, similar to Example 1, the reflective imaging element 6 is shifted by a shift amount ΔZ = +0.33 mm in a direction perpendicular to the beam deflection surface BS. Thereby, as shown in Fig. 3b, the curvature of a scanning line is reduced and set so that it is relatively small in the entire optical scanning area, so that this curvature of the scanning line is excellently corrected.

Example 4

Under the above prerequisite, which is described in Example 3, similar to Example 2, the optical axis of the imaging element 6 is inclined by a tilt angle ΔR = + 0.17 ° with respect to the beam deflection surface BS. The curvature of a scan line is as shown in Fig. 3c, so that this curvature of the scan line is excellently corrected.

In the examples given above, the surface 5 b of the semitransparent mirror 5 on the side of the reflecting imaging element is a semi-transparent mirror surface. Fig. 1d schematically shows only a main part of the optical scanner in an embodiment in which the third embodiment of the invention is used in the optical scanner shown in Fig. 1a. In Fig. 1d, the surface 5 a of the semi-transparent mirror 5 on the side of the deflection device 4 is formed by a semi-transparent mirror surface. An optical axis of the reflective imaging element 6 is fixed on the beam deflecting surface BS. Similar to Examples 1 and 2, the above three parameters, which define the shape of the mirror surface of the imaging element 6 , are set to R _m = -277 mm, R _S = -91 mm and K = -0.33. Furthermore, the semi-transparent mirror 5 has a refractive index n = 1.51118 and a thickness t = 3.5 mm. The mirror 5 is inclined at an angle α = 450 with respect to the beam deflection surface BS. From the stand L ₀ from the reflective deflection surface 4 a to the imaging element 6 is 87.42 mm and the optical scanning width S is set to 216 mm.

Under this condition, the semi-transparent Spiegelflä surface of the mirror 5 is arranged on the side of the image forming element 6 , and the shift amount ΔZ and the tilt angle ΔR are set to zero. In this case, a curvature of a scan line is created, as shown in Fig. 4a.

Example 5

Under the above condition, the semi-transparent mirror surface of the mirror 5 is arranged on the side of the deflection device 4 , as shown in Fig. 1d. The curvature of a scan line is improved, as shown in Fig. 4b. If the semi-transparent mirror surface of the mirror 5 is arranged on the side of the deflection device 4 , a deflected light beam is passed through the semi-transparent mirror surface and is then transmitted three times through the semi-transparent mirror. Consequently, a light path of the light beam in the mirror 5 can be enlarged, so that the length of the entire light path of the light beam is longer. At the same time, as shown in Fig. 4b, the curvature of a scan line is effectively corrected.

In this case, as shown in Example 5, the curvature of the scanning line is improved even if no reflective imaging member 6 is shifted or tilted. The curvature of the scan line can generally be corrected by aligning the semi-transparent mirror surface of the mirror on the side of the deflector and moving or tilting the reflective imaging member 6 .

For example, the three parameters which determine the shape of the mirror surface of the reflective imaging element 6 are set to R _m = - 252 mm, R _S = -96 mm and K = -1.0. Furthermore, the semi-transparent mirror 5 has a refractive index n = 1.51118 and a thickness t = 3.2 mm. The mirror 5 with the semi-transparent mirror surface is inclined by an angle α = 45 ° with respect to the beam deflection surface BS. The distance L ₀ from the reflective deflection surface 4 a to the reflective imaging element 8 is 76.5 mm and the optical scanning width S is set to 216 mm.

Under such a condition, the shift amount ΔZ and the tilt angle ΔR of the reflective imaging member 6 are set to zero. Furthermore, the semi-transparent mirror surface of the mirror 5 is fixed on one side of the reflective imaging element 6 . In this case, the curvature of a scan line is created, as shown in Fig. 5a Darge.

Example 6

If the semi-transparent mirror surface of the mirror 5 is fixed on one side of the deflection device, and the reflective imaging element 6 is displaced away from the beam deflection surface by a displacement quantity ΔZ = +0.25 mm, the curvature of a curve is created, as shown in FIG . 5b is shown, so that this curve is excellently improved.

Example 7

In the above-described prerequisite, which is described in the example 6 , the curvature of a scanning line is also superbly improved, as shown in Fig. 5c, when the reflective imaging element at a tilt angle ΔR = + 0.15 ° instead of the position shift of the reflective imaging member is inclined.

In order to correct the curvature of the scanning line, the reflective imaging element 6 can be inclined with respect to the beam deflection surface BS and the imaging element 6 can be moved in a direction perpendicular to the beam deflection surface BS.

FIG. 6a shows schematically only a main part of an optical scanner with each ge the eighth to fourteenth embodiments Mäss an embodiment of the invention. For the sake of simplicity, the structural parts which correspond to those in FIG. 1 are denoted by the same reference symbols.

A light beam is emitted from a light source 1 and a lens 2 with a positive refractive power prevents the light beam from being diverged. The light beam is transmitted through the lens 4 and then divided into parallel, convergent and divergen te light beams according to the refractive power and an arrangement of the lens 2 . In this embodiment, the light beam transmitted through the lens 2 is converted into the divergent light beam. The divergent light beam which has been transmitted through the lens 2 is converged by a cylindrical lens 3 only in a direction corresponding to the cross-scanning direction. The divergent light beam is then focused and produced as a linear image that extends in a direction corresponding to the main scanning direction in the vicinity of a reflecting surface of a deflection device 4 .

The light beam deflected by the deflection device 4 then strikes a reflective imaging element 6 via a flat parallel plate 5 A. When the deflected light beam is reflected on the image forming member 6 , the light beam is changed into a reflected light beam with which a surface of a recording medium 7 is illuminated and which converges as a light spot on a peripheral surface of the recording medium 7 for an image forming operation on the image forming member 6 becomes. An optical scanning using the light spot is ideally never carried out on an optical scanning line L in accordance with the deflection of the deflected light beam. Thus, ideally, a scan line of the light spot coincides with the optical scan line L. In practice, however, the scanning line of the light spot is generally curved and shifted with respect to the optical scanning line L.

Similar to the imaging element 6 described with reference to FIG. 1 a, the reflective imaging element 6 is also executed here by an anamorphic concave mirror 6 with a concave, barrel-shaped surface. The shape of a mirror surface of the imaging element 6 is determined by the three parameters R _m , R _S and K mentioned _above .

As mentioned above, the light beam incident on the deflector 4 is formed as a linear image extending in the direction corresponding to the main scanning direction in the vicinity of the reflective deflecting surface. By the reflective imaging member 6 , positions of the reflective deflecting surface and a scanned surface are set in a conjugate relationship in a geometric optic in the direction corresponding to the cross-scanning direction. Consequently, this embodiment is also an embodiment of an optical scanner with a 14th structure.

Fig. 6b shows an optical path of the light beam from the deflection device 3 to the recording medium 7 in the optical scanner shown in Fig. 6a, from the direction corresponding to the main scanning direction. The shape of a mirror surface of the reflective Bil derzeugungselements 6 shown in Fig. 6b is formed by a circular arc with a Radi us R _S. Furthermore, a beam deflecting surface BS and an optical axis AX of the imaging element 6 are provided; the optical axis AX runs parallel to the beam deflecting surface BS. As a result, a tilt or inclination angle ΔR is zero.

The light beam deflected by the deflection device 4 is passed through a flat parallel plate 5 A and strikes the image-forming element 6 . If the light beam is reflected on the imaging element 6 , it is passed through the plane parallel plate 5 a, and a recording medium 7 is optically scanned by this light beam. Accordingly, this embodiment is also an embodiment of an optical scanner having a ninth structure.

FIGS. 7 to 9 show modified embodiments of the optical scanner. Here, elements which correspond to those in FIGS. 6a and 6b are designated with the same reference symbols. In each of these modified embodiments, an optical arrangement of the light path of a light beam from a light source to a deflection device corresponds to that shown in FIGS. 6a and 6b. Furthermore, according to the embodiment shown in FIGS. 6a and 6b, the positions of a reflecting the deflecting surface and a scanned surface are set approximately by a reflecting imaging element 6 in conjugate relationship in a geometric optic with respect to a direction corresponding to the scanning direction.

The modified embodiment shown in FIG. 7 is an embodiment of an optical scanner having a tenth structure. A flat parallel plate 5 b is arranged so that only a deflected light beam in the direction of the imaging element from the flat parallel plate 5 B is passed.

The modified embodiment shown in FIG. 8 is an embodiment of an optical scanner with a twelfth structure. In FIG. 8, a reflective thin film is 5 m formed on a surface portion of a plane parallel plate 5 A on the side of a deflection Rich direction 4. A light beam reflected by the image generating element 6 is passed through the flat parallel plate 5 A and is then reflected on the layer 5 M. The reflected light beam is then passed back through the flat parallel plate 5 A in the direction of a medium 7 .

The modified embodiment shown in FIG. 9 is egg ne embodiment of an optical scanner with a 13th construction. In Fig. 9a, a reflective thin layer 5 m is formed on a surface part of a flat parallel plate 5 A on the side of an image forming member 6 . A light beam reflected by the element 6 is reflected on the reflective layer 5 m and transmitted to a recording medium 7 .

A practical example of an optical scanning will next be described in the optical scanner with reference to the embodiment shown in Figs. 6 to 9, respectively. In each of these games, a shape of the reflective imaging member 6 is given by specifying the aforementioned three parameters R _m , R _S and K. A material of the flat parallel plate is determined by a refractive index n, and a shape of the flat parallel plate is determined by thickness t. An arrangement form of the plane parallel plate is determined by specifying an inclination angle α with respect to a direction parallel to the axis of rotation of the deflection device. In all examples, the refractive index n of the plane parallel plate is set to 1.51118. In this case, a beam deflection surface is flat.

A light beam from a light source is changed by a lens 2 into a divergent light beam. A distance S ₀ between a divergence starting point of this divergent light beam and a mirror surface of the imaging element 6 is predetermined. The divergence starting point of the divergent light beam is fixed in a position in a geometric optic, in which it is taken into account that the divergent light beam begins to diverge. If the distance S ₀ is set accordingly, a position of the light source in a direction corresponding to the main scanning direction is defined with respect to a deflected light beam which impinges on the reflecting de imaging element 6 . The aforementioned divergence starting point of the divergent light beam is fixed at a point in front of the mirror surface of the element 6 . Consequently, this distance S _{0 is represented} by a negative distance.

In Examples 8 to 30 below, an optical axis of the reflective imaging member 6 is parallel to a beam deflecting surface. A distance between the aforementioned optical axis of the imaging member 6 and the beam deflecting surface is provided as a "shift amount" of the reflective imaging member. A distance L ₀ from the aforementioned divergence starting point to the imaging element is set to 66.1079 mm in Examples 8 to 30. An order form of the imaging element is determined by the aforementioned displacement size and the distance L ₀ . A "separation value" shows a distance between the beam deflecting surface and a reflected light beam in the position of a reflecting deflecting surface or on any of the surfaces of the flat parallel plate. A "curvature of a scan line" shows a maximum value of a shift between the actual scan line and the aforementioned optical scan line L.

First practical examples 8 to 19 are examples in the embodiment shown in Figs. 6a and 6b. The separation value shows a distance between the beam deflecting surface in the position of the reflecting deflecting surface and the reflected light beam.

Example 8

t = 4 mm; α = 15 °; S ₀ = -314.089; K = -1.87; R _m = -223.0; R _S = -110.5; Sliding size: 0.41 mm; Separation value = 0.91 mm; Curvature of scan line = 4 µm.

Example 9

t = 4 mm; α = 30 °; S ₀ = -314.089; K = -1.87; R _m = -223.0; R _S = -110.5; Sliding size: 0.71 mm; Separation value = 1.75 mm; Curvature of scan line = 11 µm.

Example 10

t = 4 mm; α = 45 °; S ₀ = -314.089; K = -1.87; R _m = -223.0; R _S = -110.5; Sliding size: 0.70 mm; Separation value = 2.36 mm; Curvature of scan line = 21 µm.

Example 11

t = 8 mm; α = 60 °; S ₀ = -314.089; K = -1.89; R _m = -223.0; R _S = -110.63; Sliding size: 0.00 mm; Separation value = 2.35 mm; Curvature of scan line = 31 µm.

Example 12

t = 8 mm; α = 15 °; S ₀ = -292.339; K = -1.85; R _m = -218.7; R _S = -108.8; Sliding size: 0.86 mm; Separation value = 1.84 mm; Curvature of scan line = 7 µm.

Example 13

t = 8 mm; α = 30 °; S ₀ = -292.339; K = -1.85; R _m = -218.6; R _S = -108.0; Sliding size: 1.50 mm; Separation value = 3.50 mm; Curvature of scan line = 19 µm.

Example 14

t = 8 mm; α = 45 °; S ₀ = -292.339; K = -1.88; R _m = -218.8; R _S = -108.2; Sliding size: 1.48 mm; Separation value = 4.72 mm; Curvature of scan line = 40 µm.

Example 15

t = 8 mm; α = 60 °; S ₀ = -292.339; K = -1.81; R _m = -218.8; R _S = -108.7; Sliding size: 0.11 mm; Separation value = 4.69 mm; Curvature of scan line = 62 µm.

Example 16

t = 12 mm; α = 15 °; S ₀ = -249.97; K = -1.81; R _m = -210.0; R _S = -105.5; Sliding size: 1.42 mm; Separation value = 2.94 mm; Curvature of scan line = 6 µm;

Example 17

t = 12 mm; α = 30 °; S ₀ = -259.68; K = -1.83; R _m = -211.6; R _S = -104.2; Sliding size: 2.50 mm; Separation value = 5.70 mm; Curvature of scan line = 24 µm.

Example 18

t = 12 mm; α = 45 °; S ₀ = -286.93; K = -1.86; R _m = -216.5; R _S = -104.2; Sliding size: 2.47 mm; Separation value = 7.41 mm; Curvature of scan line = 60 µm.

Example 19

t = 12 mm; α = 60 °; S ₀ = -292.339; K = -1.89; R _m = -217.2; R _S = -105.1; Sliding size: 0.38 mm; Separation value = 7.20 mm; Curvature of scan line = 93 µm;

The following examples 20 to 23 are concrete examples relating to the embodiment shown in FIG. 8. The separation value shows a distance between a beam deflection surface of the flat parallel plate on the side of the deflection device and a reflected light beam.

Example 20

t = 8 mm; α = 15 °; S ₀ = -292.339; K = -1.85; R _m = -218.7; R _S = -108.7; Sliding size: 0.95 mm; Separation value = 1.32 mm; Curvature of scan line = 8 µm.

Example 21

t = 8 mm; α = 30 °; S ₀ = -292.339; K = -1.86; R _m = -218.6; R _S = -107.9; Sliding size: 1.67 mm; Separation value = 2.47 mm; Curvature of scan line = 23 µm.

Example 22

t = 8 mm; α = 45 °; S ₀ = -292.339; K = -1.89; R _m = -218.6; R _S = -107.9; Sliding size: 1.72 mm; Separation value = 3.12 mm; Curvature of scan line = 45 µm;

Example 23

t = 8 mm; α = 60 °; S ₀ = -292.339; K = -1.91; R _m = -218.8; R _S = -108.0; Sliding size: 0.40 mm; Separation value = 2.93 mm; Curvature of scan line = 66 µm;

The following Examples 24 to 26 are practical examples of an optical scanner with an eleventh structure corresponding to the embodiment shown in Figs. 6a and 6b, in which the angle of incidence of a reflected light beam incident on the flat parallel plate is adjusted accordingly by a Brewster -Angle enough. The separation value shows a distance between a beam deflection surface in the position of a deflection starting point and a reflected light beam.

Example 24

t = 4 mm; α = 56.506 °; S ₀ = -314.089; K = -1.89; R _m = -223.0; R _S = -110.65; Sliding size: 0.24 mm; Separation value = 2.42 mm; Curvature of scan line = 29 µm.

Example 25

t = 8 mm; α = 56.506 °; S ₀ = -292.339; K = -1.89; R _m = -218.6; R _S = -109.0; Sliding size: 0.58 mm; Separation value = 4.81 mm; Curvature of scan line = 58 µm.

Example 26

t = 12 mm; α = 56.506 °; S ₀ = -292.339; K = -1.89; R _m = -217.2; R _S = -105.6; Sliding size: 1.05 mm; Separation value = 7.35 mm; Curvature of scan line = 86 µm;

The following example 27 is a concrete example of an optical scanner with an eleventh structure according to the embodiment shown in FIG. 8 Darge, in which the angle of incidence of a deflected light beam incident on the flat parallel plate is adjusted accordingly to a Brewster angle are enough. The separation value shows a distance between a beam deflection surface of the parallel plate on the side of the deflection device and a deflected light beam

Example 27

t = 8 mm; α = 56.506 °; S ₀ = -292.339; K = -1.9; R _m = -218.6; R _S = -108.0; Sliding size: 0.86 mm; Separation value = 3.05 mm; Curvature of scan line = 62 µm;

The following examples 28 to 30 are practical examples of the optical scanner each according to the embodiment shown in FIGS. 7 and 8. The separation value shows a distance between a deflected light beam of the plane parallel plate on the side of the reflecting image forming element and a reflected light beam in the direction of an axis of rotation of the deflection device.

Example 28

t = 12 mm; α = 30 °; S ₀ = -292.339; K = -1.71; R _m = -218.8; R _S = -113.3; Sliding size: 1.8 mm; Separation value = 2.28 mm; Curvature of scan line = 37 µm.

Example 29

t = 12 mm; α = 45 °; S ₀ = -292.339; K = -1.74; R _m = -218.8; R _S = -112.0; Sliding size: 1.8 mm; Separation value = 3.28 mm; Curvature of scan line = 83 µm.

Example 30

t = 12 mm; α = 60 °; S ₀ = -292.339; K = -1.85; R _m = -219.5; R _S = -108.45; Sliding size: -0.1 mm; Separation value = 3.93 mm; Curvature of scan line = 83 µm;

FIG. 10a to 32a respectively show field curvatures with respect to the above-mentioned examples 8 to 30. Further, Figs. 10b-32b respectively Abtastkenndaten relating to the same Examples 8 to 30. In each of the available vault diagrams in FIGS. 10a to 32a shown frame, a solid line a Sagittal ray and a dashed line a meridional ray like that. When the height of an ideal image at a deflection angle R of the deflected light beam is set to H (R) and the real image height is set to H '(R), the scanning characteristics are determined by the following formula

[{H ′ (R) -H (R)} / H (R)] × 100%

The scan characteristics correspond to fR characteristics of an fR lens. In each of these examples are the field curvature and the scan characteristics are excellent and the curvature of a scanning line is in Maximum equal to or less than 0.1 mm as mentioned above, so that the field curvature, the scan characteristics and the curvature the scan line are excellently corrected.

In each of the examples given above, the shape of a mirror surface of the reflective imaging element is determined by the three parameters R _m , R _S , and K. However, the invention can also be applied to a case in which an image-forming member whose mirror surface has a different shape is used.

Fig. 33a schematically shows only a main part of an embodiment of an optical scanner, each with the 15th to 19th embodiment according to the invention. Here, the elements which correspond to those in FIG. 1a are designated by the same reference characters.

A light beam is emitted from a light source 1 , and a lens 2 with a positive refractive power prevents the light beam from being diverged. The light beam is transmitted through the lens 2 and changed into a parallel, convergent and divergent light beam in accordance with the refractive power and an arrangement of the lens 2 . In this embodiment, the light beam transmitted by the lens 2 is fixed to the divergent light beam. The transmitted through the lens 2 , di-convergent light beam is converged by a cylindrical lens 3 only in the direction corresponding to the cross-scanning direction. The divergent light beam is then focused and formed as a linear image, which extends in a direction corresponding to the main scanning direction, in the vicinity of a reflecting surface of a deflector 4 .

The light beam deflected by the deflection device 4 then strikes a reflective imaging element 6 via an elongated prism 50 . When the deflected light beam is reflected on the image forming member 6, the light beam is changed to a reflected light beam, with which a surface of a recording medium 7 is illuminated and wel cher as a light spot on a peripheral surface of Aufzeich drying medium 7 by an image forming operation of the reflec leaders imaging element 6 is converged. Optical scanning using the light spot is ideally carried out on an optical scanning line corresponding to the deflection of the deflected light beam. Consequently, ideally, a scanning line from the light spot coincides with the optical scanning line L. In reality, however, the scanning line of the light point is generally curved and shifted with respect to the optical scanning line.

According to the reference to FIG. Explained 1a, reflective imaging element 6, this element is formed by a Anamor photic concave mirror 6 6, which has a concave, barrel-shaped surface. The shape of a mirror surface of the Bil derzeugungselements 6 is determined by the aforementioned three parameters R _m , R _S and K.

As mentioned above, the light beam impinging on the deflector 4 is formed as a linear image, which extends in the direction corresponding to the main scanning direction, in the vicinity of the reflecting deflecting surface. By the imaging element 6 positions of the deflection surface and a scanned te surface in a conjugate relationship in a geometric optics of the direction corresponding to the scanning direction is set. Consequently, this embodiment is also an embodiment of an optical scanner with a 19th construction.

Fig. 33b shows an optical path of the light beam from the deflecting device 4 to the recording medium 7 in the optical scanner shown in Fig. 33a, and that seen from the direction corresponding to the main scanning direction. The shape of a mirror surface of the imaging element 6 shown in FIG. 33b is formed by a circular arc with a radius R _S. Furthermore, a beam deflection surface BS and an optical axis AX of the reflected imaging element are entered, the optical axis AX running parallel to the beam deflection surface BS. The light beam deflected by the deflection device 4 is transmitted through the elongated prism 50 and strikes the image forming element 6 . When the light beam is reflected by the element 6 , a recording medium 7 is optically scanned by this light beam. The elongated prism 50 is arranged so that a longitudinal direction of this prism is parallel to the direction corresponding to the main scanning direction. A cross-sectional area of the elongated prism 50 is formed as a wedge shape. A surface of the elongated prism 50 on the deflector 4 side extends perpendicular to the beam deflecting surface BS. Consequently, a light emitting surface of the prism 50 is inclined with respect to the beam deflecting surface BS.

Therefore, a direction of emission of the deflected light beam emitted from the prism 50 is inclined by refraction from the light emitting surface thereof with respect to the beam deflecting surface BS.

Accordingly, the light beam is incident on the imaging member 6 in a state in which this light beam is inclined with respect to the optical axis AX of the member 6 . Consequently, who separated the light paths of the incident and one of the element 6 re reflected light beam by forming an angle between the incident and the reflected light beam in egg ner to the beam deflection perpendicular direction. This direction is set corresponding to a vertical direction in Fig. 33b.

Fig. 34a shows an incident position of the deflected light beam incident on the element 6 in the optical arrangement of Fig. 33b when a deflection angle of the deflected light beam is set to zero and a large angle. When the deflection angle of the deflected light beam is set to zero, a direction of the deflected light beam, which is transmitted from the deflection device 4 in the direction of the prism 50 , runs parallel to the optical axis of the element 6 and is represented by a solid line. When the deflection angle of the deflected light beam is set to a large angle, the direction of the deflected light beam is shown by a broken line.

When the deflection angle of the deflected light beam is set to zero, the light beam refracted by the prism 50 strikes the image-forming element 6 at a corresponding point on its optical axis. An incident angle of the deflected light beam incident on the light-emitting surface of the elongated prism 50 is changed as the deflection angle of the deflected light beam becomes larger. As a result, a refractive angle of the light beam is also gradually changed on the light emitting surface of the prism 40 . As the deflection angle of the light beam becomes larger, the position of a light spot on the scanned surface is shifted in the direction corresponding to the cross-scanning direction, as shown by a broken line in Fig. 34a, so that the curvature of a scanning line becomes larger.

Fig. 34b shows an embodiment of an optical scanner with a structure 16 according to the invention. In this embodiment, the image forming element 6 is shifted from an arrangement state shown in FIG. 34a in a direction perpendicular to the beam deflecting surface BS. The optical axis AX of the element 6 , which runs parallel to the beam deflecting surface BS, is between an incident position of the deflected beam impinging on the element at a deflection angle of zero, which is represented by a solid line, and an impinging position on the element 6 impinging, deflected light beam set at a maximum deflection angle, which is represented by a dashed line in an effective optical scanning range. According to such an arrangement, a curvature of a scan line is corrected.

Fig. 34c shows an embodiment of an optical scanner with a seventeenth construction according to the invention. In this embodiment, the reflective imaging member 6 is inclined from its arrangement state shown in Fig. 34a by an angle Δβ with respect to a straight line which is parallel to a direction corresponding to the main scanning direction and passes through an intersection of a mirror surface and an optical axis of the element 6 through. The direction corresponding to the main scanning direction is set to a direction perpendicular to a paper plane of FIG. 34c. With such an arrangement, the curvature of a scan line is corrected.

The following example 31 is a practical example of the optical scanner having the sixteenth structure shown in Fig. 34b. A shape of the reflective imaging member 6 is determined by the aforementioned three parameters R _m , and R _S and K. The elongated prism 50 has a refractive index n, a thickness t and a vertical angle δ at an incident position of the deflected light beam incident on the imaging element. As mentioned above, a reference symbol L ₀ denotes a distance from a deflection starting point of the light beam deflected by the deflection device to the reflective imaging element 6 . A writing width of the light beam in an optical scanning operation is set to 216 mm. In this embodiment, a shift amount of the element 6 in its arrangement state is set to zero in Fig. 34a. In Fig. 34a, a shift amount of the member 6 is set positive (+) when the reflective imaging member is shifted toward the upper side.

Example 31

t = 4 mm; δ = 10 °; n = 1.51118; L ₀ = 66.11; K = -1.72; R _m = -222.0; R _S = 108.3; Sliding size: 6.45 mm.

The following example 32 is a practical example of the optical scanner having the seventeenth structure shown in Fig. 34a. R _m , R _S , K, n, t and L ₀ correspond to the respective values in Example 30 with regard to their meaning. The writing width of a light beam in an optical scanning is set to 216 mm. In this embodiment, a tilting or tilting angle of the reflective imaging member in its arrangement state in FIG. 34a is zero and is also set to negative (-) when the member 6 is tilted counterclockwise as shown in FIG. 34c.

Example 32

t = 4 mm; δ = 10 °; n = 1.51118; L ₀ = 66.11; K = -1.72; R _m = -222.0; R _S = 108.3; Tilt angle -3.4 °.

Fig. 35a shows a curvature of a scanning line when a shift quantity of Ver, and a tilt angle of the reflecting Bilderzeu restriction member in each of Examples 31 and 32 to zero is is shown. Fig. 35b and 35c show states of the scan line, after the curvature of the scanning line in each of Examples 31 and 32 is corrected. Of course, the curvature of the scan line is effectively corrected in each of Examples 31 and 32.

In the embodiment shown in Figs. 33a and 33b, the image forming member 6 is set to be anamoric photo and adjusts positions of the reflecting surface of the deflector and the scanned surface in a conjugate relationship with respect to the direction corresponding to the cross-scanning direction. As a result, an inclination of the reflecting surface of the deflector is corrected. In contrast to a rotating polygon mirror, the deflection of a reflecting surface of the cone-shaped (tenon type) mirror, which is mentioned as the deflection device, is relatively small. Consequently, in many cases the inclination of the reflecting surface need not be corrected in practice. In such cases, it is also not necessary to design the reflective imaging element as an anamorphic element. According to an 18th construction of the invention, a mirror surface of the imaging element can be formed by a coaxial spherical or aspherical surface with rotational symmetry about an optical axis of the reflective imaging element be formed.

The following example 33 is a practical example of an optical scanner with the 18th construction according to the invention. The reflective imaging element has an axial aspherical surface. A shape of the imaging element is determined by a radius of curvature R on its optical axis and a ko constant K. Reference symbols n, t, δ and L ₀ correspond to those in Example 31 with regard to their meaning.

The writing width of a light beam in an optical scan is set to 216 mm.

Example 33

t = 4 mm; δ = 10 °; n = 1.51118; L ₀ = 137.76; K = 2.14; R = -387.0; Sliding size = 29.62 mm.

In Example 33, when the shift size of the reflective imaging member is set to zero, the member having a coaxial aspherical surface is arranged as shown in Fig. 34a. In this case, the curvature of a scan line is large, as shown in Fig. 36a. However, the curvature of the scan line can be effectively corrected and reduced as shown in FIG. 36b by setting the displacement size of the element to 29.62 mm as in Example 33 and the element as in FIG. 34b, is arranged.

In Fig. 37a is shown only a main part of an optical scanner, each with a 21 to 26 structure according to a wide ren embodiment of the invention schematically. Elements which correspond to those in FIG. 6a are designated with the same reference symbols. A light beam is emitted from a light source 1 , and a lens 2 with positive refractive power prevents the light beam from being diverged. The light beam is transmitted through the lens 2 and modified in accordance with the refractive power and arrangement of the lens 2 into a parallel, convergent or divergent light beam. In this embodiment, the light beam let through by the lens 2 is set as a di-light beam. The divergent light beam transmitted by the lens is converged by a cylindrical lens 3 only in a direction corresponding to the cross-scanning direction. The divergent light beam is then focused and generated as a linear image that extends in a direction corresponding to the main scanning direction in the vicinity of a reflecting surface of a deflector 4 .

The light beam deflected by the deflection device 4 then strikes a reflective imaging element 6 via a flat parallel surface 5 A. When the deflected light beam is reflected on the element 6 , it is changed into a reflected light beam which illuminates a surface of a recording medium 7 and is converged as a light spot on a peripheral surface of the recording medium 7 by an image forming process of the element 6 . A scan line is generally curved and shifted with respect to an optical scan line L.

According to the reference to FIG. 1 explained above image forming member 6, the element 6 is designed as an anamorphic concave mirror 6 with a concave, barrel-shaped surface. The shape of a mirror surface of the element 6 is determined by the three parameters R _m , R _S and K mentioned above.

According to the embodiment shown in FIG. 6a, the light beam impinging on the deflection device 4 is generated as a linear image, which runs in the direction corresponding to the main scanning direction, in the vicinity of the reflecting deflection surface. By the image forming member 6 positions are set the deflection surface and reflecting a scanned surface in a conjugate relationship in a geometric optics in the cross-scan direction corresponding direction. Accordingly, this embodiment is also an embodiment of an optical scanner having a 26th structure.

Fig. 37b shows an optical path of the light beam from the deflecting device 4 to the recording medium 7 in the optical scanner shown in Fig. 37a, from the direction corresponding to the main scanning direction. The shape of a mirror surface of the element 6 shown in FIG. 37b is formed by a circular arc with a radius R _S. Furthermore, a beam deflection surface BS and an optical axis AX of the element 6 are designated. In contrast to the embodiment shown in FIGS. 6a and 6b, the optical axis AX in this embodiment is inclined by a predetermined angle ΔR with respect to the beam deflecting surface BS. The deflected by the deflection device 4 light beam is let through by a flat parallel plate 5 A and strikes the image-forming element 6 . When the beam is reflected on the element 6 , it is transmitted through the plate 5 A, and an optical medium 7 is optically scanned by means of this light beam. Consequently, this embodiment is also an embodiment of an optical scanner with a 21st structure.

Fig. 38 to 40 show a modified embodiment of the optical scanner. Here, elements which correspond to those in FIGS. 37a and 37b are designated with the same reference symbols. In each of the modified embodiments, an optical arrangement of the light path of a light beam from a light source to a deflection device corresponds to that shown in FIGS. 37a and 37b. According to the embodiment shown in FIGS. 37a and 37b, the positions of a reflecting and a scanned surface are set by a reflecting imaging element 6 in a conjugate relationship in a geometric optic with respect to a direction corresponding to the transverse scanning direction.

The modified embodiment shown in FIG. 38 is an embodiment of an optical scanner with a 22nd construction. A plane parallel plate 5 B is arranged so that only a deflected light beam is transmitted in the direction of the element 6 from the ebe NEN plate 5 B.

The modified embodiment shown in Fig. 39 is ei ne embodiment of a scanner with a 24th structure. In Fig. 39, a reflective thin layer 5 M is formed on a surface part of a flat parallel plate 5 A on the side of a steering device 4 . A reflected on a Bilderzeugungsele element 6 light beam is let through from the plate 5 A and 5 M reflected on the layer. The reflected light beam is in turn transmitted from the parallel plate 5 A to a recording medium 7 .

The embodiment shown in FIG. 40 is an embodiment of an optical scanner with a 25th structure. In Fig. 40, a reflective layer is 5 m on a surface portion of a plane parallel plate 5 A on the side of reflecting the imaging element 6 is formed. A light beam reflected by the element 6 is reflected on the layer 5 m and transmitted to a recording medium 7 .

Next, an example of optical scanning in the optical scanner according to the embodiments shown in Figs. 37 to 40 will be described. In each of these examples, a shape of the element 6 is determined by the aforementioned three parameters R _m , R _S and K. A material of the flat parallel plate is determined by a refractive index n and the plate density is determined by t. An arrangement form of the plate is determined by specifying an inclination angle α from a direction parallel to the axis of rotation of the deflection direction. In all examples, the refractive index n of the parallel plate is set to 1.51118.

A light beam from a light source is changed into a divergent light beam by a lens 4 . A distance S ₀ between a divergence starting point of this divergent light beam and a mirror surface of the reflective imaging element is provided. The divergence starting point of the divergent light beam is fixed in a position in the geometrical optics, in which it is taken into account that the divergent light beam starts to be divergent. When the position S _{0 is} set, a position of the light source in a direction corresponding to the main scanning direction with respect to a deflected light beam impinging on the element 6 is determined. The aforementioned divergence starting point of the divergent light beam is set in a position in front of the mirror surface of the element 6 . Consequently, this distance S _{0 is represented} by a negative distance.

In the following Examples 34 to 43, the optical axis of the reflective imaging member 6 is inclined by a tilt or inclination angle ΔR (unit: degree) with respect to a beam deflection surface. A distance from the above-mentioned deflection starting point on the imaging element is set to L ₀ . An arrangement form of the element is determined by the angle of inclination ΔR and the distance L ₀ .

A "separation value" shows a distance between the beam deflection surface and a reflected beam in one position reflective deflection surface or on one of the surfaces of the ebe NEN parallel plate. A "curvature" of the scan line shows one Maximum value of a shift between the actual Ab scanning line and the aforementioned optical scanning line L.

First examples 34 to 39 are examples of the embodiment shown in Figs. 37a and 37b. In these examples, the separation value shows a distance between the beam deflecting surface in the position of the reflecting deflecting surface and the reflected light beam.

Example 34

t = 4 mm; α = 15 °; S ₀ = -306.11; L ₀ = 66.11; K = -1.87; R _m = -223.0; R _S = -110.5; ΔR = 1.1; Separation value = 2.4 mm; Curvature of scan line = 7 µm.

Example 35

t = 4 mm; α = 60 °; S ₀ = -296.11; L ₀ = 66.11; K = -1.89; R _m = -221.2; R _S = -109.7; ΔR = 1.1; Separation value = 2.4 mm; Curvature of scan line = 27 µm.

Example 36

t = 8 mm; α = 15 °; S ₀ = -296.11; L ₀ = 66.11; K = -1.89; R _m = -218.7, R _S = -108.8; ΔR = 0.8; Separation value = 1.8 mm; Curvature of scan line = 22 µm.

Example 37

t = 8 mm; α = 60 °; S ₀ = -296.11; L ₀ = 66.11; K = -1.86; R _m = -218.8; R _S = -108.7; ΔR = 2.20; Separation value = 4.6 mm; Curvature of scan line = 54 µm.

Example 38

t = 12 mm; α = 15 °; S ₀ = -296.61; L ₀ = 68.61; K = -1.77; R _m = -218.0; R _S = -109.05; ΔR = 1.2; Separation value = 2.7 mm; Curvature of scan line = 8 µm.

Example 39

t = 12 mm; α = 60 °; S ₀ = -296.11; L ₀ = 66.11; K = -1.87; R _m = -217.2; R _S = -105.1; ΔR = 3.6; Separation value = 7.3 mm; Curvature of scan line = 54 µm.

The following Examples 40 and 41 are examples in the embodiment shown in FIG. 39. In these examples, the separation size shows a distance between the beam deflecting surface of the plane parallel plate 5 A on the deflector side and the reflected light beam.

Example 40

= 8 mm; α = 30 °; S ₀ = -292.339; L ₀ = 66.11; K = -1.86; R _m = -218.6; R _S = -111.3; ΔR = 1.63; Separation value = 2 mm; Curvature of scan line = 23 µm;

Example 41

t = 8 mm; α = 60 °; S ₀ = -292.339; L ₀ = 66.11; K = -1.91; R _m = -218.6; R _S = -108.0; ΔR = 2.4; Separation value = 3 mm; Curvature of scan line = 65 µm;

The following example 42 is an example of an optical scanner with a 23rd construction according to the embodiment shown in FIGS . 37a and 37b, in which the angle of incidence of a deflected light beam impinging on the parallel plate is adjusted accordingly to a Brewster Angle enough. In this example, the separation value shows a distance between the beam deflecting surface in a position of a deflection starting point and the reflected light beam.

Example 42

t = 8 mm; α = 56.506 °; S ₀ = -296.11; L ₀ = 66.11; K = -1.89; R _m = -218.6; R _S = -109.0; ΔR = 32.25; Separation value = 4.8 mm; Curvature of scan line = 44 µm;

The following example 43 is an example of the optical scanner in the embodiment shown in FIG. 38. The separation value shows a distance between the deflected light beam of the plane parallel plate on the side of the reflective imaging member and the reflected beam in a direction perpendicular to the beam deflecting surface.

Example 43

t = 12 mm; α = 45 °; S ₀ = -299.11; L ₀ = 66.11; K = -1.74; R _m = -218.8; R _S = -112.0; ΔR = 2.9; Separation value = 3.0 mm; Curvature of scan line = 54 µm;

Each of Figs. 41a to 50a shows a field curvature with respect to the above-mentioned examples 34 to 43. Each of Figs. 41b to 50b shows scanning characteristic data relating to the same examples 34 to 43. In each of these examples 34 to 43, the field curvature and the scanning characteristic data corrected excellently, and the curvature of a scan line is equal to or less than 0.1 mm at the maximum, so that the field curvature, the scan characteristics and the curvature of the scan line are excellently corrected.

Fig. 51a shows schematically only a main part of an optical scanner with a 27th structure according to a further embodiment of the invention. Elements corresponding to those in Fig. 37a are designated by the same reference numerals. A light beam is emitted from a light source 1 , and a lens 2 with a positive refractive power prevents the light beam from diverging. The light beam is passed through by the lens 1 and modified in accordance with the refractive power and an arrangement of the lens 2 into a parallel, convergent or divergent light beam. In this embodiment, the light beam transmitted through the lens 2 is changed into the divergent light beam. The divergent light beam transmitted by the lens 2 is converged by a cylindrical lens 3 only in a direction corresponding to a cross-scanning direction. The di-convergent light beam is then focused and formed as a linear image, which is in a direction corresponding to a main scanning direction, in the vicinity of a reflecting surface of a deflection direction 4 .

The light beam deflected by the deflection device strikes a reflective image-forming element 6 via a flat parallel plate 5 A. When the deflected light beam is reflected on the element 6 , the light beam is changed into a reflected light beam. Then, with the reflected light beam, a surface of a recording medium 7 is illuminated, and the light beam is converged as a light spot on a peripheral surface of the recording medium 4 in an image forming operation of the element 6 . A scan line is generally curved and shifted with respect to an optical scan line L.

According to the element 6 explained above with reference to FIG. 1 a , this element 6 is formed by an anamorphic, concave mirror 6 with a concave, barrel-shaped surface. A shape of a mirror surface of the element 6 is determined by the three parameters R _m , R _S and K mentioned above.

According to the embodiment shown in FIG. 37a, the light beam impinging on the deflection device 4 is formed as a linear image, which extends in a direction corresponding to one of the main scanning directions, in the vicinity of the reflecting deflection surface. The imaging member 6 adjusts positions of the reflecting deflecting surface and a scanned surface in a conjugate relationship in a geometric optic in the direction corresponding to a transverse direction. Accordingly, this embodiment is also an embodiment of an optical scanner with a 35th structure.

Fig. 51b shows an optical path of the light beam from the deflecting device 4 to the recording medium 7 in the optical scanner shown in Fig. 51a, seen from the direction corresponding to a main scanning direction.

The shape of a mirror surface of the imaging element 6 shown in FIG. 51b is formed by a circular arc with a radius R _S. Furthermore, a beam deflection surface BS and an optical axis AX of the element 6 are designated.

In a departure from the embodiment shown in FIGS . 37a and 37b, a light beam from a light source in this embodiment is slightly inclined with respect to the beam deflection surface BS. As mentioned above, a shift amount of the light beam is used as an index representing the relative relationship between the imaging member and an inclination of the light beam incident on the reflecting deflecting surface from the light source with respect to the beam deflecting surface.

As shown in Fig. 51b, applies a deflected light beam on a reflective surface of the element 6 via a plane parallel plate 5 A. A shift size of the light beam is shown in the unit mm and set to Δ1. This value Δ1 is a distance between an incident position P of the light beam and a central part O of the element 6 when the height of an image of a light spot on a scanned surface is set to zero. This central part O is fixed at an interface of the optical axis AX and the reflecting surface of the imaging element. The displacement is set positively when the impact position P is set under the central part O.

The light beam deflected by the deflection device 4 is transmitted through the plate 5 A and strikes the element 6 . When the light beam is reflected by the element 6 , it is transmitted through the plate 5 A, and the recording medium 7 is optically scanned by the light beam. Therefore, this embodiment is also an embodiment of an optical scanner having a 30th construction.

Fig. 52 to 54 show modified embodiments of the optical scanner rule. Elements corresponding to those in Figs. 38 to 40 are given the same reference numerals. In each of these modified embodiments, an optical arrangement of the light path corresponds to a light beam from a light source to a deflection device of that shown in FIGS. 51a and 51b. Furthermore, according to the embodiment shown in Figs. 51a and 51b, the positions of a reflective deflecting surface and a scanned surface are approximately set by a reflective imaging member 6 in a conjugate relationship in a geometric optic with respect to a direction corresponding to a cross-scanning direction.

The modified embodiment shown in FIG. 52 is an embodiment of an optical scanner having a 31st construction. A flat, parallel plate 5 B is arranged so that only a deflected light beam is passed in the direction of the element 6 from the plate 5 B.

The embodiment shown in FIG. 53 is an embodiment of an optical scanner with a 33rd structure. In Fig. 53, a reflective thin film 5 is formed in a M FLAE chenteil a plate 5 on the side of the deflection means 4. A light beam reflected on the element 6 is transmitted through the plate 5 and then reflected on the layer 5 M re. The reflected light beam is then again transmitted from the plate 5 to a recording medium 7 .

The modified embodiment shown in FIG. 54 is an embodiment of an optical scanner with a 34th construction. In Fig. 54, a reflective thin layer 5m is formed on a face portion of a flat parallel plate 5 on the side of a reflective imaging member 6 . A light beam reflected by the element 6 is reflected on the thin layer 5 m and transmitted in the direction of a recording medium 7 .

In each of FIGS. 51 to 54, an optical axis AX of the reflective imaging member 6 is arranged parallel to a beam deflecting surface BS so that a tilt or inclination angle of the member is set to zero. However, in a 28th embodiment, the aforementioned light beam shift amount can be set to zero and a finite tilt angle (other than zero). Furthermore, according to a 29th embodiment, the light beam shift size and the tilt angle can be set to a finite value (except zero).

Next, an example of optical scanning in the optical scanner according to the embodiments shown in FIGS. 51 to 54 will be described. In each of these examples, a shape of the image forming member 6 is determined by the aforementioned three parameters R _m , R _S and K. A material of the flat parallel plate is determined by a refractive index n and a shape of the plate is determined by a thickness t. An arrangement form of the plate is determined by an angle of inclination α with respect to a direction which is parallel to an axis of rotation of the deflection device. This angle of inclination α is an angle between a normal to the parallel plate and a beam deflection surface. In all of the following examples, the refractive index of the flat parallel plate is set to 1.51118.

A light beam from a light source is changed by a lens 2 into a divergent light beam. A distance S ₀ between a divergence starting point of the divergent light beam and a mirror surface of the imaging element 6 is seen easily. The divergence starting point of the divergent light beam is fixed in a position in a geometric optic, taking into account that the divergent light beam starts to become divergent. If the distance S ₀ is set accordingly, a position of the light source in a direction corresponding to the main scanning directions is determined with respect to a deflected light beam impinging on the imaging element 6 . The aforementioned divergence starting point of the divergent light beam is set in a position in front of the mirror surface of the element 6 . Consequently, this distance S _{0 is represented} by a negative distance. L ₀ is set to a distance from a deflection starting point of the light beam deflected by the deflecting device to the image forming element. An arrangement form of the element 6 is generally determined by a displacement quantity Δ1 of the light beam, a tilt angle ΔR and the distance L ₀ .

In the following examples, a "cut value" shows a distance between the beam deflection surface and a reflected beam in the position of a reflective baffle. A "Curvature of a scan line" shows a maximum value of a ver shift between the actual scan line and the previous one mentioned optical scanning line L.

First examples 44 to 49 are examples of the embodiment shown in Figs. 51a and 51b. As a result, the tilt angle ΔR is set to zero.

Example 44

t = 4 mm; α = 15 °; S ₀ = -315.1; L ₀ = 66.1; K = -1.87; R _m = -223.0; R _S = -110.5; Δ1 = 3.6; Separation value = 0.3 mm; Curvature of scan line = 28 µm.

Example 45

t = 4 mm; α = 60 °; S ₀ = -315.1; L ₀ = 66.11; K = -1.89; R _m = -223.0; R _S = -110.5; Δ1 = 5.1; Separation value = 1.4 mm; Curvature of scan line = 20 µm.

Example 46

t = 8 mm; α = 15 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.85; R _m = -218.7; R _S = -108.7; Δ1 = 4.2; Separation value = 0.5 mm; Curvature of scan line = 36 µm.

Example 47

t = 8 mm; α = 60 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.91; R _m = -218.8; R _S = -112.0; Δ1 = 7.0; Separation value = 3.6 mm; Curvature of scan line = 46 µm;

Example 48

t = 12 mm; α = 15 °; S ₀ = -311.2; L ₀ = 70.3; K = -1.73; R _m = -223.34; R _S = -112.0; Δ1 = 4.9; Separation value = 1.2 mm; Curvature of scan line = 40 µm.

Example 49

t = 12 mm; α = 60 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.89; R _m = -217.2 R _S = -105.1; Δ1 = 9.3; Separation value = 6.2 mm; Curvature of scan line = 46 µm;

The following examples 50 to 54 are examples in the embodiment shown in Figs. 51a to 51b. In these examples, the light beam displacement quantity Δ1 is set to zero and the tilt angle ΔR is set to a finite value.

Example 50

t = 4 mm; α = 15 °; S ₀ = -315.1; L ₀ = 66.1; K = -1.87; R _m = -223.0; R _S = -110.5; ΔR = 2; Separation value = 0.0 mm; Curvature of scan line = 67 µm.

Example 51

t = 4 mm; α = 60 °; S ₀ = -315.1; L ₀ = 66.1; K = -1.89; R _m = -223.0; R _S = -110.63; ΔR = 2.6; Separation value = 1.3 mm; Curvature of scan line = 9 µm.

Example 52

t = 8 mm; α = 15 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.85; R _m = -218.7; R _S = -108.7; ΔR = 2.3; Separation value = 0.7 mm; Curvature of scan line = 21 µm.

Example 53

t = 8 mm; α = 60 °; S ₀ = -293.3 L ₀ = 66.1; K = -1.91; R _m = -218.8; R _S = -218.8; ΔR = 3.8; Separation value = 3.8 mm; Curvature of scan line = 35 µm;

Example 54

t = 12 mm; α = 15 °; S ₀ = -311.2; L ₀ = 70.3; K = -1.73; R _m = -223.34; R _S = -112.0; ΔR = 2.5; Separation value = 1.2 mm; Curvature of scan line = 40 µm.

Example 55

t = 12 mm; α = 60 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.89; R _m = -217.2; R _S = -105.1; ΔR = 5.0; Separation value = 6.1 mm; Curvature of scan line = 60 µm;

The following examples 56 and 57 are examples of the optical scanner of the embodiment shown in Figs. 51a and 51b, in which the angle of incidence of a light beam incident on the plane parallel plate is set according to a Brewster angle. Thus, each of these examples 56 and 57 is an embodiment of an optical scanner with a 33rd construction.

Example 56

t = 8 mm; α = 56.506 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.89; R _m = -218.6; R _S = -109.0; Δ1 = 7.1; Separation value = 3.7 mm; Curvature of scan line = 36 µm.

Example 57

t = 8 mm; α = 56.506 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.89; R _m = -218.6; R _S = -109.0; ΔR = 3.7; Separation value = 3.6 mm; Curvature of scan line = 32 µm;

The following examples 58 and 59 are examples of the optical scanner of the embodiment shown in FIG. 52. Accordingly, each of these examples 58 and 59 is an embodiment of an optical scanner with a 31st construction.

Example 58

t = 12 mm; α = 45 °; S ₀ = -289.2; L ₀ = 69.0; K = -1.8; R _m = -218.8; R _S = -112.0; Δ1 = 8.3; Separation value = 1.7 mm; Curvature of scan line = 20 µm.

Example 59

t = 12 mm; α = 45 °; S ₀ = -284.2; L ₀ = 69.0; K = -1.8; R _m = -218.8; R _S = -112.0; ΔR = 4.3; Separation value = 1.8 mm; Curvature of scan line = 27 µm;

These numerical values in Examples 58 and 59 can be used as they are as numerical values in the embodiment shown in FIG. 54. In this case the separation value is 1.8 mm.

Examples 60 to 63 are examples of the optical scanner of the embodiment shown in FIG. 53. In examples 60 and 61, the tilt angle ΔR is set to zero. In the example 62, the light beam shift size Δ1 is set to zero. In example 63, the light beam displacement quantity Δ1 and the tilt angle ΔR are set to a finite value.

Example 60

t = 8 mm; α = 15 °; S ₀ = -294.3; L ₀ = 67.1; K = -1.85; R _m = -218.7; R _S = -108.7; Δ1 = 4.4; Separation value = 0.2 mm; Curvature of scan line = 39 µm.

Example 61

t = 8 mm; α = 56.506 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.91; R _m = -218.8; R _S = -108.0; Δ1 = 7.7; Separation value = 1.7 mm; Curvature of scan line = 56 µm.

Example 62

t = 8 mm; α = 60 °; S ₀ = -293.3; L ₀ = 66.1; K = -1.91; R _m = -218.8; R _S = -218.8; ΔR = 4.1; Separation value = 1.7 mm; Curvature of scan line = 51 µm;

Example 63

t = 8 mm; α = 15 °; S ₀ = -294.3; L ₀ = 67.1; K = -1.85; R _m = -218.7; R _S = -108.7; Δ1 = 0.2; ΔR = 2.4; Separation value = 0.2 mm; Curvature of scan line = 29 µm.

FIG. 55a to 74a respectively show a curvature of field respect Lich of Examples 44 described above to 63. Fig. 55b to 74b respectively show Abtastkenndaten with respect to Examples 44 to 63. In each of these Examples 44 to 63, the picture is field curvature and the Abtastkenndaten corrected excellently , and the curvature of a scan line is equal to or less than 0.1 mm at the maximum, so that the field curvature, the scan characteristics and the curvature of the scan line are excellently corrected.

In Examples 44 to 63 described above, the Angle of inclination of a light beam, which reflect on the de area of the deflection device with respect to the beam deflection area hits, set to 2 °, but can also be set to another Angles other than 2 ° can be set.

As mentioned above, the opti described above is cal scanner, each of the first to sixth versions has according to the invention, an optical scanner of a system for focusing and creating a point of light as one Image using the reflective imaging element that has the shape of a concave reflective surface. In this optical scanner can make an excellent optical scanning be performed by acting on the curvature of a scan line sam is reduced using a semipermeable spie gels has been created as a light path separator.

In the optical scanner, each one of the eighth to three tenth embodiment according to the invention, the light path Separating device with the help of a transparent flat parallel  plate executed. As a result, the light utilization rate is strong improved compared to a case where the half transmissive mirror used as the light path separator becomes. Furthermore, the curvature of a scan line is very strong wrestles, so that the optical scanning excellently with a ho hen speed is performed. In the optical scanner with the eleventh construction, the angle of incidence of the plate incident, deflected light adjusted accordingly approximately a Brewster angle. Hence the re flexion value of a p-polarized light component extremely reduced adorns, so that the light efficiency is improved without ir anti-reflective layer on the flat parallel plate to apply. In the optical scanner, which is the twelfth and has thirteenth construction is a degree of freedom of interpretation of an optical system larger.

In the optical scanner with the fifteenth to eight respectively tenth structure can be an optical scanning using a elongated prism as the light path separator be performed. In the optical scanner with the sixth tenth to eighteenth construction can be optical scanning before be done quickly by bending a scan line is never effectively reduced by using the elongated prism as a the light path separator is used.

In the optical scanner, each one of the twentieth to has twenty-fifth versions, the curvature of an ab tracing line excellent through light path separation effects with the help of egg a flat parallel plate and with the help of inclination effects of a reflective imaging element.

In the optical scanner, each one of the twenty-seven has the tens to thirty-fourth versions, the Krüm measurement of a scanning line, primarily through light path separation effects with the help of a flat parallel plate and with the help of Nei  effects of a light beam are corrected, with a Direction of incidence of the incident on the deflection device Light beam is inclined with respect to a beam deflecting surface. in the the curvature of the scan line can be exquisitely by the Light path separation effects using a flat parallel plate through the aforementioned inclination effects of the light beam and the tilt effects of a reflective imaging element corrections, that with respect to the beam deflection surface is inclined.

In the optical scanner, which has the 7th, 14th, 19th, 26th and 35th versions, respectively, the inclination of a deflecting surface 50 can be corrected using various types of deflecting means such as a rotating polygon mirror, etc. can.

Fig. 75 shows an embodiment of an optical scanner according to another embodiment of the invention. In Fig. 75, a divergent light beam is emitted from a semiconductor laser as a light source 1 and is passed through by a condenser lens 2 . The condenser lens 2 changes the transmitted light beam into a convergent, a divergent or a substantially parallel light beam. In this embodiment, the light beam transmitted by the condenser lens 2 is changed to a substantially parallel light beam. The light source 1 and the condenser lens 2 form a light source unit. The light beam emitted from the light source unit is then transmitted through a cylindrical lens 3 as a linear optical imaging system so that the light beam is converged only in a direction corresponding to the cross-scanning direction. The light beam is then focused and generated as a linear image, which extends in a direction corresponding to the main scanning direction, in the vicinity of a reflecting surface of an optical deflector 4 in the form of a rotating, single-surface mirror.

The light beam reflected from the deflecting surface is then reflected onto a reflecting imaging mirror 6 and a long mirror 5 . Consequently, the light beam is converged as a light spot on a photoconductive and photosensitive body 7 which is arranged so that a generating line of the photosensitive body 7 coincides with a main scanning line L on a scanned surface. The photosensitive body 7 is optically scanned by means of the light beam at a constant speed when the light beam is deflected by the optical deflector 4 at a uniform angular speed. The elongated mirror 5 is arranged accordingly in order to deflect a light path of the light beam and has no refractive power. The elongated mirror 5 and the reflective imaging mirror 6 form a light spot imaging system.

An image forming effect of the reflecting image forming mirror 6 is taken in both the main scanning direction and the cross scanning direction as follows. In the direction corresponding to the main scanning direction, a parallel light beam transmitted through the condenser lens 2 is converged by the reflective imaging mirror 6 as a light spot on the photosensitive body 7 . In the direction corresponding to the transverse direction, an image generated by the mirror 6 is set on a light spot on the photosensitive body 7 in a state in which the linear image extending in the direction corresponding to the main scanning direction and through the cylinder lens 2 has been generated, is placed on an object point, as stated above. In this embodiment, the linear image is formed in the vicinity of the reflective deflection surface. Consequently, in the direction of the cross-scan direction, the reflective imaging mirror 6 approximately adjusts positions of the reflective deflecting surface and the scanned surface in a conjugate relationship in a geometric optic. The reflective imaging mirror 6 is namely anamorphic.

In the optical scanner, in which the reflecting mirror images generation 6 is used, the deflected light beam is reflected to an incident side of the mirror. 6 Consequently, a light path of the reflected light beam must be separated from a light path of the incident light beam. Various methods for separating these light paths can be used for this purpose. In Fig. 76a to 76c three common methods are shown for separating the light paths.

Fig. 76a and 76b, a light path separation system show, respectively, in which a light beam incident on the mirror 6 with respect to the cross scan direction is the direction corresponding tends ge, which is set to a vertical direction. In Fig. 76a reflected by the mirror 6 the light beam impinges directly on the photosensitive body 7. In Fig. 76b, a light path of the reflected light beam is deflected by an elongated mirror 5 and is directed to a photosensitive body 7 . The light path separation system shown in FIG. 76b is used in the optical scanner shown in FIG. 75. Fig. 76c, a light path separation system shows at wel chem an elongated semi-transparent mirror is used 8.

Next, the relationship between the light path separation systems shown in Figs. 76a to 76c and the aforementioned deflecting scanning surface will be described. A deflected light beam is ideally deflected in principle onto the light path separation system shown in FIG. 76c. No area that has been scanned by a main beam of the deflected light beam is flat in the light path separation systems shown in FIGS. 76a and 76b. The deflecting scan surface is a plane defined in the light path separation system shown in Fig. 76c. However, this definition is extended to the light path separation systems shown in Figs. 76a and 76b. Namely, when a deflected light beam is inclined with respect to a surface that is perpendicular to an axis of rotation of the reflecting deflecting surface, as shown in Figs. 76a and 76b, the deflecting scanning surface is set to a plane which is an impact position of the incident on the reflecting deflecting surface Light beam passes through and is perpendicular to the axis of rotation of the reflective deflecting surface as an ideal axis of rotation. This incident light beam corresponds to the deflected light beam, which generates a predetermined 37099 00070 552 001000280000000200012000285913698800040 0002004401731 00004 36980e image height.

In the light path separation systems shown in Figs. 76a and 76b, the locus of an incident position of the deflected light beam incident on the mirror 6 is not parallel to the direction corresponding to the main scanning direction, which is perpendicular to the paper plane of Figs. 76a and 76b, but is formed in the shape of a curve. Consequently, the curvature of a scan line is mainly caused in such light path separation systems. However, such curvature can be reduced to such an extent by the following reduction methods that there are no practical difficulties. In this reduction method, an optical axis of the reflecting image forming mirror 6 is inclined with respect to a deflecting scanning surface, or a position of the mirror 6 is thereby provides turned, is moved that the mirror 6 easily be in a direction parallel that is perpendicular to the deflecting scanning. Otherwise, the tilting method combines the inclination and the parallel displacement of the reflective imaging mirror. A correction amount of the scan line curvature can be set by an execution condition. However, the optical scanner must be optically arranged and designed accordingly, in order to actually correct this curvature as planned. If there is an error in the optical arrangement, a scan line curvature, which cannot actually be neglected, is caused, even if the scan line curvature can be corrected during the design.

In this embodiment, a scan line curvature caused by a defect in the optical arrangement is corrected by panning (or rotating) and moving settings of the reflective imaging mirror by means of a setting mechanism 80 . The shape of a reflective surface of the imaging mirror can be adjusted on a spherical surface that is coaxial and symmetrical. In the optical scanner, which has a 39th construction, this reflecting surface of the mirror is set on a gel surface so that optical scanning can be preferably performed at a uniform speed.

In the optical scanner with a fortieth construction, a linear image, which by an optical, a linear image generating system has been generated near the reflec Defining surface defined. It also provides an optical Light spot imaging system approximately positions the reflec ting deflection surface and the scanned surface in a con jugated relationship in a geometric optic with respect to a a direction corresponding to a cross scan direction. Hence is not a converging position of a light beam in a Cross-scan direction regardless of an inclination of the reflection renden scanning area shifted.

An anamorphic, reflective imaging mirror is created used in the optical scanner, which has a 46th construction. In in this case, a field curvature in the cross-scanning direction and corrected an inclination of the reflective scanning surface without the aforementioned long cylindrical lens, a toro  id-shaped lens, etc. can be used.

Before explaining various embodiments, first described the shape of an aspherical surface. This aspherical Surface is not coaxial, but is used in some of the following Examples as a surface of the reflective imaging Mirror used.

As shown in FIG. 78, a reference sign Rs denotes a maximum radius of curvature of a reflecting surface of the image-forming mirror 6 at an intersection of an optical axis and the reflecting surface. With a reference Rm a minimum radius of curvature of the reflecting surface of the mirror 6 is designated at this intersection. These maximum and minimum radii of curvature relate to two mutually perpendicular symmetrical surfaces of the reflecting surface. These two symmetrical surfaces enclose the optical axis of the reflecting surface and are perpendicular to each other. The maximum radius of curvature Rs is a radius of curvature of an intersection between a symmetrical surface and the reflecting surface at the intersection of the optical axis and the reflecting surface. This one symmetrical surface is called a symmetrical surface of maximum curvature. The minimum radius of curvature Rm is a radius of curvature of an intersection between the other symmetrical surface and the reflected surface at the intersection of the optical axis and the reflecting surface. The other symmetrical surface is called the symmetrical surface of minimal curvature.

The intersection line between the symmetrical surface of minimal curvature and the reflecting surface is shown by a horizontal dashed line in Fig. 78. In the following description, X denotes a coordinate in a direction of the optical axis and Y denotes a coordinate in a direction perpendicular to the optical axis on the symmetrical surface with minimal curvature with the aforementioned intersection as the zero point. Denoted by K a conical constant. In this case, an intersection line between the symmetry surface minima ler young and the reflecting surface is created by a curve which is represented by the following formula (1).

X = Y ² / [Rm + √ {Rm ² - (1 + K)) X ² }] (1)

In Fig. 78, an axis AXM is perpendicular to the symmetry surface of minimal curvature at a position separated by the radius of curvature Rm from the aforementioned intersection on the optical axis. An axis AXS is perpendicular to the optical axis on the symmetrical surface of minimal curvature in a position which is distant from the aforementioned intersection by the radius of curvature Rs.

The reflecting surface of the image-forming mirror 6 is an anamorphic aspherical surface in the form of a barrel-shaped toroidal surface, which is formed by rotating the curve (which is shown by the horizontal broken lines in Fig. 78), which represents the above formula (1) the AXS axis has been obtained. The mirror 6 is used in such a way that a direction of the axis AXS is parallel to a direction corresponding to the main scanning direction. A curve obtained by adding higher-order correction terms AY ² + BY ³ + ---- to the above formula (1) can be used if necessary.

In Fig. 79, a light path from the light source is shown to the abgeta continuous surface in a state in which the egg ner main scanning direction is set corresponding direction in the vertical direction. The cylindrical lens 3 is arranged as a linear optical imaging system. R _1M is a radius of curvature of a surface of the cylindrical lens 3 on the light source side in the direction corresponding to the main scanning direction. R _2M is a radius of curvature of a surface of the cylinder lens 3 on the reflective deflecting surface side in the direction corresponding to the main scanning direction. R _1S is a radius of curvature of a surface of the cylindrical lens 3 on the light source side in the direction corresponding to the cross-scanning direction. R _2S is a radius of curvature of a surface of the cylindrical lens 3 on the side of the reflective deflecting surface in the direction corresponding to the scanning direction. Rm is a radius of curvature of the reflecting surface of the imaging mirror 6 on the optical axis in the direction corresponding to the main scanning direction. K is a conical constant. Rs is a radius of curvature of the reflecting surface of the image-forming mirror 6 in the direction corresponding to the cross-scanning direction. d ₀ is a distance from the reflective deflection surface 41 to the reflective surface of the mirror 6 . d ₁ is a distance from the aforementioned reflecting surface to a scanned surface 7 '. d ₂ is a thickness of the cylindrical lens 3 . With n is a refractive index of the cylindrical lens 3 . d ₃ is a stand between the cylindrical lens 3 and the reflective steering surface 4 '.

In the following examples, S ₀ denotes a position of an object point which is provided when an image is generated by means of the mirror 6 in the direction corresponding to the main scanning direction. S ₀ namely denotes a distance from the reflecting surface to the object. S ₀ is set negatively if this object point is arranged in front of the reflecting surface. S ₀ is therefore set to be negative if the object point is arranged on the light source side on the light path. R is a deflection angle (unit: degree) of a light beam deflected by an optical deflector 4 . f _M is a focal length of the mirror 6 in the direction corresponding to the main scanning direction and is normalized to 100.

In a first embodiment, the optical scanner is designed as shown in FIG. 81b. A deflected light beam, which has been reflected on the mirror 8 , is converged by an elongated cylindrical lens 10 as a light spot on the scanned surface. The cylindrical lens 10 is arranged near the scanned surface in a state in which a longitudinal direction of the cylindrical lens 10 is parallel to a main scanning direction. The cylindrical lens 10 has the function of correcting an inclination of the reflective deflecting surface.

According to FIG. 76a to 76c 81a, Fig. An optical path of the optical deflector 4 on the scanned surface. The light path separation system shown in FIG. 76a is used in FIG. 81a. In this embodiment, the light beam emitted from the light source unit is divergent. Furthermore, the light beam impinging on the reflecting deflecting surface is divergent in the direction corresponding to the main scanning direction. In this embodiment, the mirror 6 has a coaxial aspherical surface as the mirror surface. A shape of the mirror surface is determined by the radius of curvature R (= Rs = Rm) of this mirror surface on the optical axis and by the conical constant K. R _3m is a radius of curvature of a surface of the cylindrical lens 10 on an incident side in the direction corresponding to the main scanning direction. The direction corresponding to the main scanning direction is set to a longitudinal direction of the cylindrical lens 10 . R _3s is a radius of curvature of a surface of the cylindrical lens 10 on the incident side in the direction corresponding to the cross-scanning direction. R _4m is a radius of curvature of a surface of the cylinder lens 10 on a light emitting side in the direction corresponding to the main scanning direction. R _4s is a curvature radius of a surface, the cylindrical lens 10 on the light emitting side in the direction corresponding to the cross-scanning direction. With d _{2 '} is a thickness of the cylindrical lens. With n 'a refractive index of a material of the cylindrical lens 10 is referred to net. With d _{3 '} is a distance between the light emitting side surface of the cylindrical lens 10 and the scanned surface.

Example 64

As shown in Fig. 81a, the light beam which strikes the reflective deflecting surface of the optical deflector 4 is inclined at an angle ω with respect to the deflecting scanning surface HS. This angle ω is shown in degrees and is set clockwise to be positive. The mirror 6 and the cylindrical lens 10 are displaced in order to correct the curvature of a scanning line, which in principle is caused by this inclination. The mirror 6 is shifted in a direction perpendicular to the scanning surface HS, so that a distance from the scanning surface HS to the mirror 6 is set to Z3. The cylindrical lens 10 is displaced in a direction perpendicular to the scanning surface HS, so that a distance from the scanning surface HS to the cylindrical lens 10 is set to Z4. In Fig. 81a, the distances Z3 and Z4 from the scanning surface HS are set positively on an upper side. The values for the angle ω and the distances Z3 and Z3 are as follows:

l = 4.0; Z3 = -0.860; Z4 = 14.587.

FIG. 82a to 82c show a curvature of field, Abtastkenndaten or the curvature of a scan line, if the example is ideally realized 64th In Fig. 82a, a solid line gives the field curvature in a cross-scanning direction and a dashed line shows the field curvature in a main scanning direction like that. If the height of an ideal image is set to Hi (R) at a deflection angle R, and if the real image height is set to Hr (R), the scanning characteristics are determined by

[{Hr (R) / Hi (R)} - 1] × 100 (%)

defines and corresponds to fR parameters, which are determined by an fR Lens are set. The curve of the scan line is approximately equal to 44 µm. In practice, this curvature value does not lead to any Difficulties.

If the above example 64 is realized and a position of the cylindrical lens 3 is shifted by +1.1 mm in the direction corresponding to the transverse scanning device by an error in the optical arrangement, the scanning line is strongly curved, as shown in FIG. 83a, so that a curvature value at a maximum deflection angle of ± 48.60 equals 128 µm.

At the same time, an angle of rotation of the mirror 6 is set such that the mirror 6 is rotated by 0.2 ° counterclockwise in Fig. 81a about an axis which is perpendicular to the paper plane of Fig. 81a and through an intersection of the optical axis and passes through the mirror plane. From this setting, the curvature of the scanning line is corrected excellently, as shown in Fig. 83b, so that a maximum curvature value is 69 µm.

If there is a defect in the optical arrangement, the scan line is curved as mentioned above, and a position of the scan line is shifted on the scanned surface in the cross scan direction. In Fig. 77 this shifted to state is shown. Fig. 77 is referred to a suitably designed scan line with a reference symbol _L0. This appropriately dimensioned scan line is an ideal scan line, which is realized when each of the optical elements is mounted with high accuracy. If there is an error in the optical arrangement, the scanning line is curved as indicated by a reference character L ₁ , and is shifted ver by a distance ie ₁ from a position of the ideal scanning line L ₀ in the cross-scanning direction.

At the same time, a curvature value of the scan line, as shown by a reference character L ₁ 'in Fig. 77, is reduced according to a correction method of the scan line curvature, so that the scan line is approximated to a straight line. Furthermore, the position of the scan line of the ideal scan line L _{0 is} approximated. Consequently, the distance between these scan lines is reduced to ₁ '.

In example 64, the shift size ie ₁ is 0.38 mm, as shown in FIG. 38a, if there is an error in the optical arrangement. After the angle of rotation of the mirror 6 is set, the shift size ie ₁ 'is equal to 0.38, as shown in Fig. 83b. As a result, the shift size did not change before and after this setting.

In example 65 an optical arrangement is used which corresponds to that in example 64. In example 65, the light beam emitted by the light source unit is set to a convergent light beam. Correspondingly designed numerical values of the aforementioned radii of curvature etc. are as follows. The meaning of characters R _1M , R _1S , etc. correspond to those used in Example 64.

Example 65

FIG. 84a to 84c show a curvature of field, Abtastkenndaten or the curvature of a scanning line, when the example is carried out 65 ideal. A curvature value of the scan line is at most a small value, such as about 88 μm, so that there are no difficulties in practice.

If the example 65 is carried out accordingly and a position of the cylindrical lens 4 is shifted by -0.5 mm in the direction corresponding to the transverse scanning device by an error in the optical arrangement, the scanning line, as shown in FIG. 85a, is strongly curved , and a curvature value of the scanning line is never 122 µm at a maximum deflection angle of ± 49.60. A shift size ie _{1 of} this scan line from the position of an ideal scan line is equal to ± 0.058 mm.

If the mirror 6 is moved in a direction perpendicular to the scanning surface by + 4.1 mm, the curvature value of the scanning line is preferably corrected to a maximum of up to 42 μm, as shown in FIG. 45b. At the same time, the shift size ie ₁ 'is equal to 0.492 mm. This shift size is approximately large, but there are no difficulties when performing an optical scan with a single optical scanner.

In Example 66, which corresponds to Examples 64 and 65 above, one surface of the image-forming mirror is designed as a coaxial aspherical surface. An arrangement of the optical scanner in Example 66 is shown in Fig. 86. In the example 66, the light path separating device shown in FIG. 76c is used. In Fig. 86, a reference numeral 8 designates a beam splitter. In principle, no scanning line is curved in this light path separation system.

In example 66, the light beam emitted by the light source unit is essentially a parallel light beam. A deflected light beam reflected on the mirror 6 is converged on the scanned surface by an elongated toric lens 11 , thereby correcting the inclination of a light reflecting surface. The cylindrical lens 3 converges the light beam from the light source unit only in the direction corresponding to the cross scanning direction. This light beam is focused and formed as a linear image in the direction corresponding to the main scanning direction in the vicinity of the reflecting deflecting surface.

Through the imaging mirror 6 and the elongated to rische lens 11 positions of the reflective deflecting surface and the scanned deflection surface are set in a conjugate relationship in a geometric optic with respect to the direction corresponding to the Querab scanning direction. The mirror 6 converges the deflected light beam on the scanned surface with respect to the direction corresponding to the main scanning direction.

A surface of the toric lens 11 on the incident side on the side of the image-forming mirror 6 is designed as a barrel-shaped, toric surface, as is explained with reference to FIG. 78. A light emitting side surface of the toric lens 11 on the side of the scanned surface is formed by a normal toric surface. Similar to the examples 64 and 65, R _{3m is} a radius of curvature of the incident side surface of the toric lens 1 with respect to the direction corresponding to the main scanning direction. The direction corresponding to the main scanning direction is set to a longitudinal direction of the toric lens 11 . R _3s is a radius of curvature of the incident side surface of the toric lens 11 with respect to the direction corresponding to the cross-scanning direction R _4m is a radius of curvature of the light-emitting side surface of the lens 11 with respect to the direction corresponding to the main scanning direction. R _4s is a radius of curvature of the light-emitting side surface of the lens 11 with respect to the direction corresponding to the cross-scanning direction. With d ₂ 'a thickness of the toric lens 11 is designated. With n 'a refractive index of a material is referred to as the toric lens 11 . With d ₃ 'is a distance between the light emitting side surface of the toric lens 11 and the scanned surface.

Example 66

Fig. 87ab and 87b show a th field curvature or Abtastkennda, if the example is ideally realized 66th As stated above, no scan line is curved. When the example 66 is executed and a position of the cylindrical lens 3 is shifted by + 0.3 mm of an error in the optical arrangement, the scanning line is curved as shown in Fig. 88a, and a curvature value of the scanning line is maximum equal 40 µm. The shift size ie _{1 of} this scan line from the position of an ideal scan line is equal to -0.046 mm.

If the mirror 6 and the toric lens 11 are each moved in a direction perpendicular to the deflecting scanning surface by + 0.51 mm, a maximum curvature value of the scanning line is corrected up to 24 μm, as shown in FIG. 88b. At the same time, the shift size ie ₁ 'is equal to + 0.567mm. In this case, the deflecting scanning surface is formed by a beam splitter 8 a. The deflecting scanning surface is used even in such a case.

If the imaging mirror 6 and the toric lens 11 are moved independently of one another in the direction perpendicular to the deflecting scanning surface by + 0.3 mm or by +1.01 mm, a curvature value of the scanning line is a maximum of up to 1.8 µm corrected in an excellent manner, as shown in Fig. 88c. At the same time, the shift size ie ₁ 'is equal to + 1,053 mm.

In the following examples 67 to 70, an area of the image-forming mirror is formed by a barrel-shaped, toric area, as explained with reference to FIG. 78. In each of Examples 67 to 69, a linear image generated by the cylindrical lens 3 is set near the reflecting deflecting surface.

In an arrangement of the optical scanner in Example 87, an elongated toric lens is removed from the optical arrangement shown in FIG. 86. The light beam emitted by the light source unit is a convergent light beam. The linear image generated by means of the cylindrical lens 3 is fixed in the vicinity of the reflecting deflection surface. Through the mirror 6 , positions of the reflecting deflecting surface and the scanned surface are set in a conjugate relationship in a geometric optic by an anamorphic, barrel-shaped, toric surface with respect to the direction corresponding to the cross-scanning direction.

According to example 66, light paths of the light beam are separated from one another with the aid of the beam splitter 8 a. Consequently, no scanning line is curved in a correspondingly designed optical arrangement.

Example 67

Fig. 89a and 89b show a th field curvature or Abtastkennda, if the example is ideally realized 67th As mentioned above, no scan line is then curved. If the example 67 is carried out accordingly and a position of the cylinder lens 3 in the direction corresponding to the cross-scanning direction is shifted ver by an error in the optical arrangement by + 0.4 mm, the scanning line is strongly curved, as shown in FIG. 9a , and a curvature value of the scan line is 91 µm at the maximum. A shift size ie _{1 of} this scan line from the position of an ideal scan line is then equal to 0.436 mm. This shift size is large.

If the mirror 6 is moved in a direction perpendicular to the deflecting scanning surface of +0.27 mm, the curvature value of the scanning line is very well corrected to a maximum of 3.5 μm, as shown in FIG. 90b. At the same time, a shift size ie ₁ 'is equal to + 0.162 mm, so that the shift size is improved.

In example 68, a semi-transparent mirror 5 a is used as a light path separator, as shown in Fig. 91. A light beam from a light source unit is set as a parallel light beam. The mirror 5 a as a light path separating device is formed by a rectangular, flat parallel plate which extends in a direction which is perpendicular to the paper plane and which has a refractive index n '. A reflective layer 5 M is formed on one side of the mirror 5 A along its longitudinal direction on the side of an optical deflector 4 . The mirror 5 a is inclined at an angle a with respect to a deflecting scanning surface. An optical axis of the mirror 6 runs parallel to the deflecting scanning surface and is shifted by a distance Δ with respect to the deflecting scanning surface. A deflected light beam is passed through the mirror 5 A and reflected on the mirror 6 . The reflected light beam is then again transmitted through the semitransparent mirror 5 A in an opposite direction and is reflected on the reflecting surface 5 M. The light beam then strikes a surface to be scanned, as shown in FIG. 91. The overall optical arrangement of the scanner corresponds to the arrangement shown in FIG. 75. If the optical distances d ₀ , d ₁ ', d ₂ ', and d ₃ 'are set as shown in Fig. 91, parameters such as radii of curvature, etc. are provided as in Example 68.

Example 68

FIGS. 92a to 92c show a field curvature, scanning characteristic data or the curvature of a scanning line if the example 68 is ideally carried out. A maximum curvature value of the scanning line is then 26 µm.

If the example 68 is carried out accordingly, and a position of the cylindrical lens 3 in the direction corresponding to the cross-scanning direction is shifted by an error in the optical arrangement by + 0.5 mm, the scanning line is curved, as shown in FIG. 93a, and a curvature value of the scan line is 77 µm in maximum. A shift size ie _{1 of} this scan line from the position of an ideal scan line is equal to -0.791 mm. This shift size is large.

When the imaging mirror 6 is moved in a direction perpendicular to the deflecting scanning surface by + 0.16 mm, the curvature value of the scanning line is corrected to 40 µm as shown in Fig. 93b. At the same time, a shift size ie ₁ 'is equal to + 0.369 mm, so that the shift size is improved.

In a modified embodiment shown in FIG. 94, a reflecting surface 5 m of a semitransparent mirror 5 B is formed on one side of the mirror 6 . Furthermore, another semi-transparent mirror can be used instead of the semi-transparent mirror 5 B.

In the following example 69, a prism 5 C with a refractive index n 'is used as a light path separator, as shown in Fig. 95. The entire arrangement of the optical scanner is shown in Fig. 99. A light beam emitted by the light source is divergent. In Fig. 95, a setting angle α (degrees) of a surface facing the incident side of the prism 5 C is set from a direction perpendicular to a reflecting deflecting surface. The angle α is set positive clockwise. An inclination angle β of the optical axis of a mirror 6 is set with respect to the reflecting deflecting surface. The angle β is also set clockwise positive.

If optical distances d ₀ , d ₁ ', d ₂ ' and d ₃ 'are set, as shown in FIG. 95, parameters such as curves, etc. are created as in Example 69.

Example 69

FIG. 97a to 97c show a curvature of field, Abtastkenndaten or the curvature of a scanning line when the example is carried out 69 ideal. A maximum curvature value of the scanning line is 63 µm. If the example is carried out according to the position of 69 and a cylindrical lens 3 in a scanning direction which is the direction corresponding to Abeam by a fault in the optical system's to + 0.3 mm shifted, is sharply curved scan line, as shown in Fig. 98a is , and a curvature value of the scanning line is 147 µm in the maximum. A shift size ie _{1 of} this scan line from the position of an ideal scan line is equal to -0.836 mm. This shift value is large.

When the mirror 6 is moved in a direction perpendicular to the deflecting scanning surface 5 by + 0.34 mm, the curvature value of the scanning line is corrected to 70 µm, as shown in Fig. 98b. At the same time, a shift size ie ₁ 'is equal to + 0.275 mm, so that the shift size is improved.

In a modified embodiment shown in FIG. 96, a prism 5 c is used, the upper side of this prism being turned downward. In one example 70, a plane ne parallel plate 9 with a refractive index n 'is used as a light path separator, as shown in FIG. 100. An overall arrangement of the optical scanner is shown in Fig. 103. A light beam emitted from a light source unit is a divergent light beam. In Fig. 100, an inclination angle ψ (degree) of the flat parallel plate 9 is set with respect to a deflecting scanning surface so that it is positive in the clockwise direction. Furthermore, Δ denotes a distance (mm) of the optical axis of a mirror 6 from the deflecting scanning surface. This optical axis is parallel to the scanning surface.

If optical distances d ₀ , d ₁ '', d ₂ 'and d ₃ ' are set to who, as shown in Fig. 100, and d ₁ 'is the thickness of the plate 9 , applies: d ₁ ' = d ₁ ′ ′ sin ψ parameters such as radii of curvature, etc. are then as provided in the following example 70.

Example 70

Fig. 101a to 101c show a curvature of field, Abtastscanndaten or the curvature of a scanning line, when the sample 70 is ideally realized. A maximum curvature value of the scanning line is 60 µm.

If the example 70 is carried out and the position of a cylinder lens 3 is shifted in a direction corresponding to the transverse scanning directions by + 0.3 mm in the case of an error in the optical arrangement, the scanning line is strongly curved, as shown in FIG. 102a, and a maximum curvature value of the scanning line is 144 µm. If the shift amount ie _{1 this} scan line from the position of an ideal scan line is 0.774 mm. This shift size is a great value.

If the imaging mirror 6 is moved in a direction perpendicular to a deflecting scanning surface by + 0.36 mm, the path of curvature of the scanning line is corrected to 69 µm, as shown in Fig. 102b. At the same time, a shift value is ₁ ′ equal to + 0.375 mm, so that the shift value is improved. In each of the examples, the distance ie ₁ 'between an ideal and the scan line after the curvature correction is never improved compared to the distance between the ideal and the scan line before the curvature correction. If the distance is ₁ 'small, there is no difficulty when a write operation is performed using a single optical scanner. However, this is the case when a significant color shift is caused by a positional shift of the scan line in a two-color printer, etc., to perform a write operation using two or more optical scanners.

In such a case, the light away deflecting mirror 5 shown in FIG. 76b is arranged such that this mirror 5 can be rotated about an axis which is parallel to a longitudinal direction of this mirror. The above-mentioned distance dh ₁ 'is then corrected and brought to zero by adjusting the inclination of a reflecting surface of this light path deflecting mirror 5 . In the above description, rotation and movement of the image-forming mirror are set separately. The above-mentioned distance ie ₁ 'can be corrected precisely by such rotation and movement settings.

As stated above, the above can be described NEN optical scanner according to the invention a curvature of a Scan line, which is caused by errors in the manufacture or at the assembly of each of the optical elements is caused, wel form the optical scanner, easily and reliably in one corrected to such an extent that in practice there are none Difficulties arise.

Claims (53)

1. Optical scanner, characterized in that from a steering device has a reflective deflecting surface which is rotated at a constant speed;
a beam of light from a light source is deflected by the deflecting device at a constant angular velocity onto a plane, and strikes a reflective imaging member via a semi-transparent mirror which is inclined with respect to a beam deflecting surface, and
the light beam reflected on the imaging member is reflected on the semitransparent mirror and is converged by an imaging operation of the imaging member as a light spot on a surface to be scanned to perform an optical scanning operation,
wherein the reflective imaging member functions to perform the optical scanning operation by means of the light spot at a constant speed, and
the reflective imaging member is arranged to be shifted by a predetermined shift amount in a direction perpendicular to the beam deflecting surface to correct the curvature of a scan line on the surface to be scanned. 2. Optical scanner, characterized in that from a steering device has a reflective deflecting surface which is rotated at a constant speed;
a light beam is deflected from a light source by the deflecting device at a constant angular velocity onto a plane, and via a semitransparent mirror which is inclined with respect to a beam deflecting surface,
impinges on a reflective imaging element, and the light beam reflected on the imaging element is reflected on the semitransparent mirror and is converged by a imaging process of the imaging element as a light spot on a surface to be scanned to perform an optical scanning operation,
wherein the reflective imaging member functions to perform the optical scanning operation by means of the light spot at a constant speed, and
the reflective imaging member is arranged so that an optical axis of the reflective imaging member is inclined by a predetermined tilt angle with respect to the beam deflecting surface to correct the curvature of a scan line on the surface to be scanned. 3. Optical scanner, characterized in that a deflection device has a reflective deflecting surface which is rotated at a constant speed;
a light beam is deflected from a light source by the deflecting device onto a plane at a constant angular velocity, and via a semitransparent mirror which is inclined with respect to a beam deflecting surface,
strikes a reflective imaging member, and
the light beam reflected on the imaging member is reflected on the semitransparent mirror and is converged by an imaging operation of the imaging member as a light spot on a surface to be scanned to perform an optical scanning operation,
wherein the reflective imaging member functions to perform the optical scanning operation by means of the light spot at a constant speed, and
the semi-transparent mirror has a semi-transparent mirror surface on the side of the deflector. 4. Optical scanner according to claim 3, characterized in that the reflective imaging member is arranged so that it is a predetermined shift size in one to the Beam deflection surface is shifted to the vertical direction Curvature of a scanning line on the surface to be scanned is correct rig. 5. Optical scanner according to claim 3, characterized in that that the reflective imaging member is arranged so that an optical axis of the imaging member about one beforehand certain tilt angle with respect to the beam deflection surface to the curvature of a scan line on the one to be scanned Correct area. 6. Optical scanner according to claim 5, characterized in that that the reflective imaging member is arranged so that the optical axis of the imaging member by one determined tilt angle with respect to the beam deflection surface ge tends, and that the imaging member by a predetermined agreed shift size in one to the beam deflection surface vertical direction is shifted to the curvature of the Ab Correct the tracing line on the surface to be scanned. 7. Optical scanner according to one of claims 3 to 6, characterized in that the reflective scanning surface of the scanning device runs parallel to the axis of rotation thereof;
the reflective imaging member positions the reflective deflecting surface of the deflector and the surface to be scanned in a conjugate relationship in a geometric optic in a direction corresponding to the cross-scanning direction, and
the light beam is focused by the light source, and
is formed as a linear image in a direction corresponding to a main scan in the vicinity of the reflective scan surface in the direction corresponding to the cross-scan direction. 8. Optical scanner, characterized in that a deflection device has a reflective deflection surface which is rotated at a constant speed; a light beam is deflected from a light source by the deflecting device onto a plane at a constant speed and is reflected on an anamorphic, reflective imaging element,
the reflected light beam is converged by an imaging process of the reflective imaging member as a light spot on a surface to be scanned to perform an optical scanning process,
wherein the reflective imaging element has the function of performing the optical scanning process with the aid of the light spot at a constant speed,
a transparent, flat, parallel plate between the deflection device and the imaging element is arranged so that the flat parallel plate is inclined by a finite angle bezüg Lich an axis of rotation of the deflector, the flat parallel plate a light path from the deflection direction to the imaging element of separates a light path from the imaging member to a surface to be scanned, and
Material, thickness and angle of inclination of the flat parallel plate is set so that the curvature of a scanning line is corrected. 9. Optical scanner according to claim 8, characterized in that that the deflected striking the imaging element Light beam and that reflected on the imaging element Beam of light from the plane parallel plate let through the. 10. Optical scanner according to claim 8, characterized in  that only that striking the imaging element, abge deflected light beam from the flat parallel plate with respect of the deflected impinging on the imaging element Light beam and that reflected on the imaging element Light beam is let through. 11. Optical scanner according to one of claims 8 to 10, there characterized in that the angle of inclination of the plane paral lelen plate is set so that an angle of incidence of the deflected light striking the flat parallel plate is set accordingly to approximately a brew enough angles. 12. Optical scanner according to claim 9, characterized in that that a reflective thin layer on a surface part of the flat parallel plate on the side of the deflector is applied so that only the light beam on the pictures generating element reflected and from the flat parallel plat is transmitted selectively on the reflective layer is reflected. 13. Optical scanner according to claim 10, characterized in that that a reflective thin layer on a surface part of the flat parallel plate on the side of the imaging element ment is formed so that only on the imaging element selectively reflected light beam at the reflective Layer is reflected. 14. Optical scanner according to one of claims 8 to 10, 12 or 13, characterized in that the reflective deflection surface of the deflection device runs parallel to the axis of rotation ver;
a light beam is focused by the light source and is formed as a linear image extending in a direction corresponding to the main scanning direction in the vicinity of the reflecting deflecting surface, and
the imaging element approximately adjusts positions of the reflective deflection surface and the surface to be scanned in a conjugate relationship in a geometric optic with respect to a direction corresponding to a cross scan. 15. Optical scanner, characterized in that a light beam from the light source is deflected by a deflecting device at a constant angular velocity and is reflected on a reflective imaging element;
the reflected light beam is converged by an image forming operation of the image forming device as a light spot on a surface to be scanned to perform an optical scanning operation;
the reflective imaging element has the function of essentially performing the optical scanning using the light spot at a constant speed;
has an elongated prism in cross-section wedge shape and pa rallel to a direction corresponding to a main scanning direction between the deflector and the imaging element is arranged, and
the elongated prism separates a light path from the deflector to the imaging member from a light path from the imaging member to the surface to be scanned. 16. Optical scanner according to claim 15, characterized in that the imaging element is arranged so that it is a predetermined shift size in one to a beam deflection surface is shifted to the narrow vertical direction correct a scan line on the area to be scanned. 17. Optical scanner according to claim 15, characterized in that the imaging element is arranged so that its op table axis about a predetermined tilt angle with respect to egg ner beam deflection surface is inclined to the curvature of an Ab  Correct the touch line on the area to be scanned. 18. Optical scanner according to claim 16, characterized in that that through a reflective surface of the imaging member a coaxial spherical or aspherical surface is formed. 19. Optical scanner according to one of claims 15 to 17, characterized in that the deflection device has a reflective deflection surface parallel to its axis of rotation,
the imaging element is anamorphic and positions the reflecting deflecting surface of the deflecting device and the surface to be scanned in a conjugate relationship in a geometric optics in a direction corresponding to a cross-scanning direction, and
the light beam is focused by the light source and is formed as a linear image extending in the direction corresponding to the main scanning direction in the vicinity of the reflective scanning surface in the direction corresponding to the cross-scanning direction. 20. Optical scanner, characterized in that a deflection device has a reflective deflection surface which is rotated at a constant speed;
a light beam is deflected from a light source by the deflecting device onto a plane at a constant speed and is reflected on an anamorphic, reflective imaging element,
the reflected light beam is converged by an imaging operation of the reflecting imaging member as a light spot on a surface to be scanned to perform an optical scanning operation, the reflecting imaging member having the function of essentially performing the optical scanning operation using the light spot at a constant speed,
a transparent, flat, parallel plate is arranged between the deflection device and the image-forming element, so that the flat parallel plate is inclined by a finite angle with respect to an axis of rotation of the deflection device,
the planar parallel plate separates a light path from the deflecting device to the imaging element from a light path from the imaging element to a surface to be scanned, the reflecting imaging element is inclined with respect to the beam deflecting surface by a predetermined tilt angle, and
Material, thickness and angle of inclination of the flat parallel plate and the tilt angle of the imaging element with respect to the beam deflecting surface is determined so that the curvature of a scanning line is corrected. 21. Optical scanner according to claim 20, characterized in that that the deflected striking the imaging element Light beam and that reflected on the imaging element Beam of light from the plane parallel plate let through the. 22. Optical scanner according to claim 20, characterized in that that only that striking the imaging element, abge deflected light beam from the flat parallel plate with respect of the deflected impinging on the imaging element Light beam and that reflected on the imaging element Light beam is let through. 23. Optical scanner according to one of claims 20, 21 or 22, characterized in that the inclination angle of the plane pa parallel plate is set so that an angle of incidence of deflected on the flat parallel plate Light beam is adjusted accordingly to approximately one Brewster angles are enough. 24. Optical scanner according to claim 21, characterized in  that a reflective thin layer on a surface part of the flat parallel plate on the side of the deflector is applied so that only the light beam on the pictures generating element reflected and from the plane parallel Plate is let through selectively on the reflective Layer is reflected. 25. Optical scanner according to claim 22, characterized in that that a reflective thin layer on a surface part of the flat parallel plate on the side of the imaging element ment is formed so that only on the imaging element selectively reflected light beam at the reflective Layer is reflected. 26. Optical scanner according to one of claims 20 to 22, 24 and 25, characterized in that the reflective deflection surface of the deflection device runs parallel to the axis of rotation thereof;
a light beam is focused by the light source and is formed as a linear image extending in a direction corresponding to the main scanning direction in the vicinity of the reflecting deflecting surface, and
the imaging element approximately adjusts positions of the reflective deflection surface and the surface to be scanned in a conjugate relationship in a geometric optic with respect to a direction corresponding to a cross scan. 27. An optical scanner, characterized in that a light beam from a light source is deflected by the deflecting device, which has a reflective deflecting surface, at a constant speed and is reflected on an amorphous, reflective imaging element,
the reflected light beam is converged by an imaging process of the reflective imaging member as a light spot on a surface to be scanned to perform an optical scanning process,
wherein the reflective imaging element has the function of performing the optical scanning process with the aid of the light spot at a constant speed,
a transparent, flat, parallel plate is arranged between the deflection device and the image-forming element, so that the flat parallel plate is inclined by a finite angle with respect to an axis of rotation of the deflection device,
the light beam impinging on the reflecting deflection surface of the deflection device is set in such a way that this light strikes the beam obliquely on a beam deflection surface;
the planar parallel plate separates a light path from the deflecting direction to the imaging member from a light path from the imaging member to a surface to be scanned, and
and the material, thickness, and angle of inclination of the plane parallel plate and a shift amount of the deflected light beam with respect to the imaging member are set so as to correct the curvature of a scan line. 28. Optical scanner, characterized in that a light beam from a light source is deflected by the deflecting device, which has a reflective deflecting surface, at a constant speed and is reflected on an amorphous, reflective imaging element.
the reflected light beam is converged by an imaging process of the reflective imaging member as a light spot on a surface to be scanned to perform an optical scanning process,
wherein the reflective imaging element has the function of performing the optical scanning process with the aid of the light spot at a constant speed,
a transparent, flat, parallel plate is arranged between the deflection device and the image-forming element, so that the flat parallel plate is inclined by a finite angle with respect to an axis of rotation of the deflection device,
the light beam impinging on the reflecting deflection surface of the deflection device is set in such a way that this light strikes the beam obliquely on a beam deflection surface;
the plane parallel plate separates a light path from the deflecting direction to the imaging member from a light path from the imaging member to a surface to be scanned; the reflective imaging member is arranged so that its optical axis is inclined at a predetermined tilt angle with respect to the beam deflecting surface, and
The material, thickness and angle of inclination of the plane parallel plate and the tilt angle of the imaging element are set so that the curvature of a scanning line is corrected. 29. Optical scanner according to claim 27, characterized in that
the reflective imaging member is arranged so that its optical axis is inclined at a predetermined tilt angle with respect to the beam deflecting surface, and
Material, thickness and angle of inclination of the plane parallel Plat te, the light beam displacement size and the tilt angle of the Bil derzeugungselements are set so that the curvature of a scan line is corrected. 30. Optical scanner according to claim 27 or 28, characterized indicates that the impinging element deflected light beam and the right on the imaging element reflected light beam from the flat parallel plate be left. 31. Optical scanner according to one of claims 27 or 29, there characterized by that only that striking the imaging element, abge deflected light beam from the flat parallel plate with respect  of the 'impinging on the imaging element' deflected Light beam and that reflected on the imaging element Light beam is let through. 32. Optical scanner according to one of claims 27 or 29, there characterized in that the angle of inclination of the plane paral lelen plate is set so that an angle of incidence of the deflected light striking the flat parallel plate is set accordingly to approximately a brew enough angles. 33. Optical scanner according to claim 30, characterized in that a reflective thin layer on a surface part of the flat parallel plate on the side of the deflector is applied so that only the light beam on the pictures generating element reflected and from the flat parallel plat is transmitted selectively on the reflective layer is reflected. 34. Optical scanner according to claim 30, characterized in that a reflective thin layer on a surface part of the flat parallel plate on the side of the imaging element ment is formed so that only on the imaging element selectively reflected light beam at the reflective Layer is reflected. 35. Optical scanner according to claim 27 or 29, characterized in that the reflective deflection surface of the deflection direction runs parallel to the axis of rotation thereof;
a light beam is focused by the light source and is formed as a linear image extending in a direction corresponding to the main scanning direction in the vicinity of the reflecting deflecting surface, and
the imaging element approximately adjusts positions of the reflective deflection surface and the surface to be scanned in a conjugate relationship in a geometric optic with respect to a direction corresponding to a cross scan. 36. Optical scanner, characterized by
a light source unit for emitting a light beam to perform optical scanning;
a linear imaging optical system to focus the light beam from the light source unit and form it as a linear image extending in a direction corresponding to the main scanning direction;
an optical deflector to reflect the light beam from the linear imaging optical system onto a reflective deflecting surface and to deflect the light beam at a constant angular velocity;
a light spot imaging system to direct the deflected light beam onto a surface to be scanned and to converge the deflected light beam as a light spot on the surface to be scanned, and
an adjusting mechanism for adjusting a position of the optical light point imaging system, which has a reflecting imaging mirror which has the function of converging a deflected light beam on the surface to be scanned in at least the direction corresponding to the main scanning direction, and optical scanning with a uniform one Speed and
wherein the adjustment mechanism adjusts a rotational movement of the reflective imaging mirror about an axis that is parallel to a deflecting scanning surface and perpendicular to an optical axis. 37. Optical scanner, characterized by
a light source unit for emitting a light beam to perform optical scanning;
a linear imaging optical system to focus the light beam from the light source unit and form it as a linear image extending in a direction corresponding to the main scanning direction;
an optical deflector to reflect the light beam from the linear imaging optical system onto a reflective deflecting surface and to deflect the light beam at a constant angular velocity;
a light spot imaging system to direct the deflected light beam onto a surface to be scanned and to converge the deflected light beam as a light spot on the surface to be scanned, and
an adjusting mechanism for adjusting a position of the optical light point imaging system which has a reflecting imaging mirror which has the function of converging a deflected light beam on the surface to be scanned in at least the direction corresponding to the main scanning direction and optical scanning with a uniform one Speed and
wherein the adjustment mechanism adjusts movement of the reflective imaging mirror in a direction perpendicular to a deflecting scan surface. 38. Optical scanner, characterized by
a light source unit for emitting a light beam to perform optical scanning;
a linear imaging optical system to focus the light beam from the light source unit and form it as a linear image extending in a direction corresponding to the main scanning direction;
an optical deflector to reflect the light beam from the linear imaging optical system onto a reflective deflecting surface and to deflect the light beam at a constant angular velocity;
a light spot imaging system to direct the deflected light beam onto a surface to be scanned and to converge the deflected light beam as a light spot on the surface to be scanned, and
an adjusting mechanism for adjusting a position of the optical light point imaging system which has a reflecting imaging mirror which has the function of converging a deflected light beam on the surface to be scanned in at least the direction corresponding to the main scanning direction and optical scanning with a uniform one Speed,
wherein the adjusting mechanism adjusts a rotational movement of the reflective imaging mirror about an axis which is parallel to a deflecting scanning surface and perpendicular to an optical axis, and
wherein the adjustment mechanism adjusts movement of the reflective imaging mirror in a direction perpendicular to the deflecting scan surface. 39. Optical scanner according to claim 36, characterized in that the reflective imaging mirror is a reflection aspherical mirror surface. 40. Optical scanner according to claim 39, characterized in that a position of the linear optical imaging system is set so that the linear image extending in the direction corresponding to the main scanning direction is generated in the vicinity of the reflecting surface of the optical deflector, and
the light spot imaging system approximately adjusts positions of the reflective deflecting surface and the surface to be scanned in a conjugate relationship in a geometric optic with respect to a direction corresponding to the cross-scanning direction. 41. Optical scanner according to claim 36, characterized in that the optical spot imaging system has a reflect has mirror that is rotatable about an axis that to  parallel to the direction corresponding to the main scanning direction runs. 42. Optical scanner according to claim 39, characterized in that that the reflective imaging mirror by a right reflecting mirror is formed, which is coaxial and aspherical is risch. 43. Optical scanner according to claim 36, characterized in that that the beam of light that hits the reflective surface of the optical deflector strikes, a divergent light beam in is the direction corresponding to the main scanning direction. 44. Optical scanner according to claim 39, characterized in that the light source unit gebil by a semiconductor laser det. 45. Optical scanner according to claim 36, characterized in that the light beam that hits the reflective surface of the op table deflector strikes, a convergent beam of light in is the direction corresponding to the main scanning direction. 46. Optical scanner according to claim 40, characterized in that that the reflective imaging mirror by one amorphous, concave mirror is formed, the different imaging functions in the main scanning direction ent speaking direction and in the cross-scan direction direction. 47. Optical scanner according to claim 46, characterized in that the optical light spot imaging system has an optical element to separate light paths from one another and that it is arranged between the optical deflector and the reflecting image forming mirror;
the separating optical element separates the light beam deflected by the optical deflector from the image beam reflected on the imaging mirror, and
the separating optical element is designed as a semi-transparent mirror or a glass plate which partially has a mirror surface formed by vapor deposition. 48. Optical scanner according to claim 46, characterized in that the optical light spot imaging system has an optical element to separate light paths from one another, and that it is arranged between the optical deflector and the reflecting image forming mirror;
the separating optical element separates the light beam deflected by the optical deflector from the light beam reflected on the imaging mirror, and the separating optical element is formed by a light beam. 49. Optical scanner according to claim 37, characterized in that the optical scanner further comprises an inclination correcting optical element to correct an inclination of the reflecting deflecting surface of the optical deflector, and
the adjustment mechanism adjusts movement of the tilt correcting optical element in the same direction as the reflecting imaging mirror. 50. Optical scanner according to claim 46, characterized net that the adjustment mechanism the movement of an inclination corrective, optical element regardless of the reflec can adjust the imaging mirror. 51. Optical scanner according to claim 40, characterized in that that the optical deflector by a rotating polygon gel, a pyramidal mirror or a rotating one single-surface mirror is formed. 52. An optical scanner according to claim 46, characterized in that the optical spot imaging system has an optical element to separate light paths from each other and that it is arranged between the optical deflector and the reflecting image forming mirror;
the separating optical element separates the light beam deflected by the optical deflector from the light beam reflected by the imaging element, and
the separating optical element is formed by a transparent, flat parallel plate which is arranged obliquely with respect to the deflecting scanning surface. 53. Optical scanner according to claim 36, characterized in that the light beam, which on the reflective deflecting surface surface of the optical deflector strikes, approximately parallel to is the direction corresponding to the main scanning direction.