JPH061822Y2 - Positioning mechanism of writing head in recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a write head positioning mechanism in a non-impact printer such as a laser beam printer or an LCS (liquid crystal shutter) pre-printer.
The present invention relates to a structure capable of supporting a write head at a predetermined position on the surface of an image carrier while always ensuring a predetermined distance.

[Prior Art and its Problems] Generally, in a non-impact type printer that writes image information without contacting the surface of the image carrier, the distance between the writing head and the image carrier greatly affects the image quality. It is required that the head be always and accurately attached to the surface of the image carrier at a fixed position. In particular, in an optical writing printer that uses light as a writing medium, since various lenses are arranged in the optical path and information pixels are imaged on the surface of the photoconductor, the surface of the photoconductor is accurately positioned on the image plane of the lens. Should be located at a pixel diameter of 0.1m.
Since it is about m, extremely high mounting accuracy is required. For this reason, a method is used in which both frames are made common, an adjustment width is provided in advance, and a screw or the like is used while adjusting with a jig or the like in the assembly process.

However, in the case of using the above-mentioned jig or the like, the assembling process becomes complicated and the number of work steps increases, and it is necessary to make adjustments using the jig each time when inspecting the head portion during maintenance, etc. This is a factor that significantly reduces the maintenance work efficiency. Further, for a printer or the like in which the photosensitive drum is replaced by a cartridge type, the mechanism becomes complicated and the attachment / detachment operation becomes difficult, which lowers the commercial value.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems of the prior art, and can accurately and easily secure the position of the writing head with respect to the surface of the image bearing member, and improve workability during assembly and maintenance. An object of the present invention is to provide a write head positioning mechanism in an excellent recording apparatus.

[Summary of the Invention] In order to achieve the above-mentioned object, according to the present invention, a writing head that irradiates an optical signal modulated according to input information toward the surface of an image carrier is located at a position facing the surface of the image carrier. In a write head positioning mechanism in a recording device configured to be separable, at least a pair of positioning protrusions are formed on the write head so as to project, and a positioning portion having a circumferential surface or a spherical surface is formed on at least a tip portion of the protrusion. Then, a deep recessed portion capable of accommodating at least the positioning portion is formed in a portion corresponding to the protrusion of the pair of supports that support the image carrier,
The projection is rotatably supported while the positioning portion is in contact with the deep end of the deep recess, and the distance from the writing head to the surface of the image carrier is always kept constant at the facing position. It is characterized in that it is configured to.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Details will be described.

FIG. 7 shows a liquid crystal shutter type optical writing printer P as one embodiment of the present invention. In the figure, the photosensitive drum 1 is rotatably supported at the substantially central portion, and is indicated by an arrow A.
Direction is driven and rotated at a predetermined speed. In the vicinity of the peripheral surface of the photoconductor drum 1, a charger 2 for uniformly charging the peripheral surface of the photoconductor drum 1 to a predetermined polarity and a liquid crystal shutter are provided along the rotation direction of the photoconductor drum 1. An optical writing head 3 for irradiating the surface of the photosensitive drum 1 with an optical signal according to information to form an electrostatic latent image, a developing unit 4 for supplying toner to the formed electrostatic latent image to form a toner image, and toner. A transfer charger 5 for transferring an image onto a transfer paper, a cleaner 6 for removing toner remaining without being transferred, and the like are sequentially arranged to form a one-cycle image forming process.

In the lower part of the machine, a transfer cassette to which transfer paper T is stacked, a paper feed roller 8, a turn guide 9, and a toner image on the photosensitive drum 1 are aligned with the transfer paper in order to align the respective leading ends of the transfer paper. A pair of registration rolls 10 and the like having a transporting timing of T are arranged, and a transfer paper carry-in path is formed. on the other hand,
On the opposite side of the transfer position, a separation roller 11 that separates and conveys the transfer paper on which the toner image is transferred from the surface of the photosensitive drum 1,
A conveyance guide 12, a fixing device F, upper and lower discharge guides 13 and 14 for discharging the transfer paper having the toner image fixed thereon, and a discharge roll pair 15 for discharging the transfer paper to a discharge tray section 16.
15 is provided and a transfer paper carry-out path is formed.

The optical writing printer P configured as described above includes the optical writing head 3, a part of the upper and lower discharge guides 13 and 14, the pair of discharge rolls 15 and 15 mounted on the upper body of the optical writing printer 3 with the shell open line S as a boundary. It can be divided into P ₁ and a lower body P ₂ on which other components are mounted. That is, the upper body P ₁ is rotatably coupled to the lower body through a hinge 17, the upper body P ₁ is the time of internal inspection, etc.
The machine body can be easily opened by rotating the machine in the clockwise direction in the figure by a predetermined angle. Further, the photosensitive drum 1, the charger 2 and the cleaner 6 are integrally formed as a drum unit U so as to be detachable from the main body of the machine body, and the developing machine 4 is also similarly formed as a unit.

Here, the configuration of the optical writing head 3 will be described with reference to FIG. The optical writing head 3 of this example has a head case 18 and a head base 19 on which an irradiation port e is formed to project.
And a lamp case 20 is formed substantially in the center thereof. In the lamp case 20, a fluorescent lamp 21 as a light source is fixed and supported by a support member 21a at a position near the irradiation port e. An opening 20a is formed in an elongated shape along the extending direction of the fluorescent lamp 21 at a position facing the irradiation port e of the lamp case 20, and a transparent dustproof glass 22 is covered on the opening 20a. On the inner surface of the head case 19 facing the opening 20a, a liquid crystal shutter array 23, which is formed by arranging a large number of liquid crystal micro shutters in parallel, is mounted with the array direction (longitudinal direction) corresponding to the opening 20a. An imaging lens array 24, which is formed by arranging a large number of imaging lenses in an array corresponding to the liquid crystal shutter array 23, is inserted into the irradiation port e. Further, the liquid crystal shutter array 23 is connected at its both ends to a pair of drive circuit boards 23b arranged along the side wall of the head case 20 via heat seals 23a, and a liquid crystal micro board is provided on the drive circuit board 23b. Drive LSI (Large Scale Integrated Circuit) 23c for controlling opening / closing of the shutter according to an input information signal
Are arranged. Therefore, the light emitted from the fluorescent lamp 21 passes through the dust-proof glass 22 through the opening 20a and reaches the liquid crystal shutter array 23, where the transmission is controlled by the liquid crystal micro-shutter that opens and closes in accordance with the information signal and is converted into an optical signal. It The shutter image as the optical signal is imaged as a pixel on the surface of the photosensitive drum 1 by the imaging lens array 24 at a magnification of 1: 1 in this example, and information is optically written.

Thus, as shown in FIGS. 1 (a) and 2, both ends of the write head 3 are provided with projections 25, 25 for positioning. The positioning projection 25 of this example is formed by forming a hemispherical surface 25a at the tip of a cylinder. On the other hand, the photosensitive drum 1 is rotatably supported by a pair of support plate portions 27, 27 in the frame 26 of the drum set U. The above-mentioned positioning projection 2 is formed on each end face of the support plate portions 27, 27 corresponding to the position where the write head 3 is disposed.
A pair of deep recesses 28 capable of accommodating the respective tips of 5 and 25;
28 'are respectively recessed. The concave portion 28 of this example is the third
As shown in the figure, each space of a wide and shallow guide portion 28a and a storage portion 28b which is narrower than the guide portion 28a and is deeply formed in a V-shaped valley shape is connected. In this case, the guide portion 28
The bottom of a is inclined toward the accommodation portion 28b so that the inclination angle is changed in two steps and the bottom is gradually lowered. Therefore, when the writing head 3 is installed on the drum set U, first, the projection tip 25a is placed on the end of the guide portion 28a having a wide opening, and then the accommodating portion 28b is provided along the inclined surface.
It is sufficient to drop it into
The insertion operation of is extremely easy. In this example, one of the pair of recesses 28, 28 ', for example, the recess 28'.
The width of the housing is formed wide without changing between the housing portion and the guide portion, which facilitates the insertion operation.

Next, the tips of the protrusions 25 and 25 and the receiving portions 28b and 28 '.
The contact mechanism will be described. In FIG. 4, the radius R of the projection tip hemispherical surface 25a and the inclination angle θ and the depth D of the accommodating portion 28b indicate the curvature of the hemispherical surface 25a in the accommodating state in which the hemispherical surface 25a is in contact with both slopes T ₁ and T _2. The center (center of the inscribed circle) O is set to be located at the same level as the peripheral surface line L of the photoconductor drum 1 indicated by the two-dot chain line. or,
The width W of the accommodating portion 28b in the concave portion 28 whose width changes
2 and 3, the thickness is set to be slightly larger than the thickness d of the protrusion 25 so that the protrusion 25 can slide smoothly. With such a structure, the write head 3
Even if the installation posture is displaced in the circumferential direction of the photosensitive drum 1 indicated by the arrow A as indicated by the chain double-dashed line, the circumferential center O of the tip serving as the position reference of the protrusion 25 is always at the peripheral surface level of the photosensitive drum 1. It is located on L, and as shown in FIG. 1 (b), the required distance l between the imaging lens array 24 and the surface of the photosensitive drum 1 can always be secured with extremely high accuracy. Therefore, it is not necessary to adjust the position of the write head 3 each time using a jig or the like at the time of assembly or disassembly inspection, and the work efficiency at the time of assembly or maintenance can be greatly improved. Further, in the shell-open type recording apparatus in which the photosensitive drum 1 and the like are exchanged into a cartridge type as in this example, the writing head 3 moves away from the photosensitive drum 1 every time the substrate is opened and closed, and writing is performed with time. Although the posture of the head 3 tends to shift, the positioning mechanism of the present invention always ensures the above-mentioned required interval l that affects the image quality with high accuracy, so that a good image can be stably obtained for a long period of time. Is possible.

Next, another embodiment of the present invention will be described with reference to FIG. In this example, the positioning projection 2 of the write head 3
The tip portion 29a of 9 is formed in a spherical shape. Therefore, the concave portion 30 on the drum unit U side that accommodates this is also formed to be thin in an inverted quadrangular pyramid shape. Also in this case, similarly to the above-mentioned embodiment, the position reference is the center O'of the sphere, and the radius R'of the sphere is set so that this O'is located on the peripheral surface level L of the photosensitive drum 1 in the housed state. And recess angle θ
And depth D '. Therefore, according to the positioning mechanism of the present example, not only the displacement of the writing head 3 with respect to the photosensitive drum 1 in the circumferential direction A, but also the displacement of the posture in the width direction B, the required distance 1 described above is always accurately maintained. It becomes possible to secure more reliably.

It should be noted that the present invention should not be limited to the above-described official embodiments and the like, and it is needless to say that various modifications can be made within the technical scope based on the claims of the utility model registration of the present invention. is there. For example, the tip of the positioning protrusion may be formed on the circumferential surface instead of the spherical surface, and the spherical surface or the circumferential surface may be formed in a necessary range without being limited to the hemisphere or the semicircle. Further, the present invention is applicable to a laser beam printer, and is also applicable to other recording devices such as an electrostatic recording system as well as an optical writing system.

[Advantage of Device] As described in detail above, according to the present invention, the position of the write head is determined by a simple contact structure of the circumference and two or more inclined surfaces, whereby the posture of the write head is improved. Even if the misalignment occurs, the required space between the writing head and the image carrier can always be stably and highly accurately ensured. Therefore, the complicated work of adjusting the position of the write head by using the jig each time at the time of assembling or disassembling is unnecessary, and the work efficiency at the time of assembling and maintenance is significantly improved. or,
Even in a unit type recording apparatus in which the image carrier can be replaced by a cartridge type, by applying the present invention, the positioning mechanism of the writing head is categorized, the operation is easy, there are few failures, and the image quality is stable. It is possible to obtain a good recording apparatus at low cost.

[Brief description of drawings]

FIG. 1 (a) is a side view showing a head positioning / contacting structure in one embodiment of the present invention, and FIG. 1 (b) is a distance l between the imaging lens array 24 and the photosensitive drum 1 in the above embodiment.
FIG. 2 is a partially cutaway front view showing the head positioning mechanism, FIG. 3 is a perspective view showing the recess 28, and FIG.
FIG. 4 is an explanatory view showing the contact mechanism, FIG. 5 is a perspective view showing another embodiment of the present invention, and FIGS. 6 and 7 are liquid crystal shutter printers as one embodiment of the present invention. 3 is a cross-sectional view showing the writing head 3 and a schematic view showing the overall configuration. 1 ... Photosensitive drum, 3 ... Writing head, U ... Drum unit, 25, 29 ... Positioning protrusions, 25a, 2
9a: tip of protrusion, 26: frame (drum unit),
27 ... Support plate portion, 28, 28 ', 30 ... Recessed portion.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/036 A 9070-5C

Claims (1)

[Scope of utility model registration request] 1. A writing head in a recording device, wherein a writing head for irradiating an optical signal modulated according to input information toward a surface of an image carrier is separated from a position facing the surface of the image carrier. In the positioning mechanism, at least one pair of positioning projections is formed on the write head so as to project, and a positioning portion formed of a circumferential surface or a spherical surface is formed on at least the tip end portion of the projections, and a pair of bearings that support the image carrier An inner narrow recess that can accommodate at least the positioning portion is formed in a portion of the support pair that corresponds to the protrusion, and the protrusion is rotatably supported while the positioning portion is in contact with the inner end of the inner recess. The writing head of the recording apparatus is formed so that the distance from the writing head to the surface of the image carrier is always kept constant at the facing position. Pod positioning mechanism.