Image developing apparatus

Abstract: In an apparatus (10) that employs a photo-sensitive sheet (1) with a surface comprised of photo-sensitive microcapsules (2Y, 2C, 2M) containing pigments or precursors thereof and which are selectively hardened when irradiated with a light image of a picture to be developed on a sheet (3) of developing paper by the pressing together of the developing paper (3) and the photo-sensitive sheet (1); the developing paper (3) and the photo-sensitive sheet (1) in contact with each other are transported in a predetermined direction of sheet travel across a back-up surface (11a), and a rotatable roller (33) disposed in opposing relation to the back-up surface (11a) and having its axis of rotation parallel to the direction of sheet travel is transported relative to the back-up surface (11a) in a direction parallel to the latter which is perpendicular to the direction of sheet travel while the roller (33) is urged towards the back-up surface (11a) with the contacting developing paper (3) and photo-sensitive sheet (1) therebetween so as to be pressed together at a relatively narrow striped-like area defined by the rolling path of the peripheral surface of the roller (33).

Description: This invention relates to image developing apparatus. It is known, for example, from Japanese laid-open patent specification 59/30537, to print or develop an image of a colour picture on a sheet of printing or developing paper using a photo-sensitive sheet having a coating of photo-sensitive microcapsules which has been irradiated with a light image of the picture. This method employs, as the photo-sensitive sheet, a base made of a suitable resin on which there is coating of uniformly distributed yellow, magenta and cyan microcapsules. Each of the microcapsules has an outer shell of a relatively soft material in which there is sealed an optically-hardenable composition containing a respective pigment or a precursor thereof. When the microcapsules are irradiated with light of respective wavelengths the optically-hardenable compositions therein are hardened. For example, irradiation with blue light hardens the yellow microcapsules containing the precursor of yellow pigment, irradiation with green light hardens the magenta microcapsules containing the precursor of magenta pigment, the irradiation with red light hardens the cyan microcapsules containing the precursor of cyan pigment. It will be appreciated that, when irradiating the photo-sensitive sheet with a light image of a colour picture, the light representing the colour picture is suitably analyzed into the three primary colours of red, green and blue, and the photo-sensitive sheet is irradiated separately with a red light image, a green light image and a blue light image by which the cyan, magenta and yellow microcapsules, respectively, are hardened in accordance with those images. After such irradiation, the photo-sensitive sheet is passed, in contact with a sheet of developing paper, through the nip between rotating pressure rollers which rotate about axes at right angles to the direction of sheet travel, and which extend across the full width of the sheet. The resulting pressure ruptures the shells of the yellow, magenta and cyan microcapsules that were not substantially hardened by irradiation with light of the corresponding wavelength. The substances containing precursors or pigments are transferred from the ruptured microcapsules to the facing surface of the sheet of developing paper which contains substances for developing the respective colour pigment from the precursor thereof. Thus, the transferred precursors from the yellow, magenta and cyan microcapsules are suitably mixed to form a developed or printed colour picture on the sheet of developing paper. When the photo-sensitive sheet and the sheet of developing paper are pressed together between rollers rotating about axes at right angles to the direction of sheet travel therebetween, very large forces have to be exerted for urging the rollers together. In order to solve the foregoing problem, it has been previously proposed, for example, as disclosed in our Japanese patent application 62/93879, to provide a developing apparatus employing a dot impact head for applying pressure to microcapsules so as selectively to rupture them in accordance with the selective optical-hardening thereof, and to transfer the respective precursors or pigments to a sheet of developing paper. In such developing apparatus, the dot impact head is moved in a predetermined path or pattern and, at any time, applies impacts to only very small incremental areas of the photo-sensitive sheet, so that the pressure required for rupturing the unhardened microcapsules can be achieved with the exertion of a relatively small force by the dot impact head. However, this developing apparatus has the disadvantage of being objectionably noisy when in use, and the useful life of the dot impact head is short. Patent Specification US-A-4 648 699 discloses apparatus for developing a picture on a receiver sheet by pressing together the receiver sheet and an imaging sheet by mounting the imaging and receiver sheets on a cylinder and applying pressure to the imaging sheet by means of a ball which is pressed against the imaging sheet and moved axially of the cylinder while the cylinder is rotated. According to the invention there is provided an apparatus for developing a picture on a sheet of developing paper from a photosensitive sheet of a type which develops said picture upon the pressing together of the sheet of developing paper and the photo-sensitive sheet, the apparatus comprising: means defining a back-up surface; means for transporting the sheet of developing paper and the photosensitive sheet in contact with each other in a predetermined direction of sheet travel across the back-up surface; a rotatable member disposed in opposing relation to the back-up surface and having an axis of rotation extending parallel to said predetermined direction of sheet travel; means mounting the rotatable member for bodily movements towards and away from the back-up surface and parallel to the back-up surface in directions perpendicular to said predetermined direction of sheet travel; and means for transporting the rotatable member relative to the back-up surface in one of said directions perpendicular to said predetermined direction of sheet travel while urging the rotatable member towards the back-up surface with the sheet of developing paper and the photosensitive sheet being in contact with each other between the rotatable member and the back-up surface so as to be pressed together thereby; characterised in that the rotatable member is a rotatable roller; the means for transporting the sheets operates intermittently so as to alternate periods of incremental movement and of rest, respectively, of the sheets; and the means for transporting the rotatable roller operates, during each of the periods of rest, to transport the rotatable roller in said one direction perpendicular to said direction of sheet travel while urging the rotatable roller towards the back-up surface, whereupon the means for transporting the rotatable roller operates to return the rotatable roller in the other of said directions perpendicular to said direction of sheet travel; and the apparatus comprises means for moving the rotatable roller away from the back-up surface during each of the periods of incremental movement of the sheets and during the return of the rotatable roller in said other direction perpendicular to said direction of sheet travel. The invention will now be described by way of example with reference to the accompanying drawings, throughout which like parts are referred to by like references, and in which: Figure 1 is a schematic sectional view of a known photo-sensitive sheet having a coating of photo-sensitive microcapsules, and which is of a type suitable for use in a developing apparatus embodying the present invention; Figure 2 is a schematic sectional view similar to that of Figure 1, but illustrating the exposed state of the photo-sensitive sheet; Figure 3 is a schematic sectional view of a previously-proposed developing apparatus; Figure 4 is an elevational view of an embodiment of developing apparatus according to the present invention, with a portion of the housing thereof shown in cross-section; Figure 5 is a sectional view taken along the line V-V in Figure 4; Figure 5A is a fragmentary sectional view similar to a portion of Figure 5, but on an enlarged scale, and illustrating another embodiment of the present invention; Figure 6 is a detailed sectional view taken along the line VI-VI in Figure 5 and showing the developing apparatus in one phase of its operation; Figure 7. 8 and 9 are views similar to that of Figure 6, but showing the developing apparatus in other respective phases of its operation; and Figures 10 and 11 are plan views showing two different positions of an actuating plate of the embodiment, for controlling the movements of a roller therein towards and away from a back-up surface. Referring initially to Figure 1, there is shown a known type of photo-sensitive sheet 1, for example, as disclosed in Japanese laid-open patent specification no 59/30537, which is suitable for use in an apparatus according to the present invention for printing or developing an image of a colour picture on a sheet 3 of developing paper. The photo-sensitive sheet 1 generally comprises a base sheet of a suitable resin, such as polyethylene terephthalate resin, polypropylene resin or polyamide resin, to which there is applied a coating or layer 2 of uniformly distributed yellow, magenta and cyan microcapsules 2Y, 2M and 2C, respectively. Each of the microcapsules 2Y, 2M and 2C has an outer shell of a relatively soft material, such as, gelatin, polyvinyl alcohol or gum arabic, which contains an optically-hardenable composition, and includes a respective pigment or a precursor thereof, such as, a photochromic dye, electrochromic dye or a leuco dye, and an ethylene-based unsaturated compound or the like. When the yellow, magenta and cyan microcapsules 2Y, 2M and 2C are irradiated with blue light, green light and red light, respectively, the optically-hardenable compositions therein are hardened and, hence, the microcapsules 2Y, 2M and 2C become sufficiently hard to resist rupturing thereof. When employing the photo-sensitive sheet 1, for printing or developing a colour picture, the light of the colour picture is analyzed into the three primary colours red, green and blue, and the photo-sensitive sheet 1 is irradiated separately with a red light image, a green light image and a blue light image by which the cyan, magenta and yellow microcapsules 2C, 2M and 2Y, respectively, are selectively hardened, as indicated at 2a in Figure 2, in accordance with the distribution of light in each of such primary colour images. After the photo-sensitive sheet 1 has been exposed for selectively hardening its microcapsules, a picture is developed therefrom on a sheet 3 of developing paper by pressing together the sheet 3 of developing paper and the exposed photo-sensitive sheet 1 so as to rupture those microcapsules which have not been hardened. In the known developing apparatus shown on Figure 3, after irradiation of the photo-sensitive sheet 1, it is passed, in contact with a sheet 3 of developing paper, through the nip between pressure rollers 4a and 4b which rotate about axes at right angles to the direction of sheet travel therebetween, and which extend across the full width of the sheets 1 and 3. The pressure exerted by the rollers 4a and 4b on the sheets 1 and 3 therebetween is sufficient to rupture the shells of the yellow, magenta and cyan microcapsules 2Y, 2M and 2C that have not been substantially hardened by irradiation with light of the corresponding wavelength. The pressure between the rollers 4a and 4b further transfers the precursors or pigments from the ruptured microcapsules to the facing surface of the sheet 3 of developing paper which contains substances for developing the respective colour pigments from the transferred precursors thereof. The pigments in three primary colours mix with each other on the sheet 3 of developing paper so as to form thereon the printed or developed colour picture. A pressure of 30 to 40 kg/mm² is required to rupture the microcapsules that have not been hardened in the exposing of the photo-sensitive sheet 1 and to ensure that the pigment precursors contained within the ruptured microcapsules are reliably transferred into intimate contact with the developing substances on the sheet 3 of developing paper. In the case of the known developing apparatus shown in Figure 3, and in which the sheets 1 and 3 are pressed together between the rollers 4a and 4b rotating about axes extending perpendicular to the direction of sheet travel therebetween, the rollers 4a and 4b contact the sheets 1 and 2 at areas thereof extending across the entire widths thereof. When the rollers 4a and 4b have diameters of 50mm, they have to be urged towards each other with a force of 57kg for each cm of the roller length in order to provide the pressure required for rupture of the microcapsules. Therefore, if the known apparatus of Figure 3 is to be employed for developing or printing a picture on a sheet of developing paper of the A4 size, that is, having a width of 21cm, the corresponding rollers 4a and 4b having axial lengths of at least 21cm would have to be urged towards each other with a force of 1200kg. it will be appreciated that, in order to apply such large force to the rollers 4a and 4b, the known developing apparatus must have a relatively complicated construction and be of large size. Referring now to Figures 4 and 5, it will be seen that an embodiment of developing apparatus 10 according to the present invention is also intended to develop or print a colour picture on a sheet 3 of developing paper which is pressed together with a photo-sensitive sheet 1 after the exposure of the latter. The apparatus 10 is shown to comprise a stage or platform 11 defining an upwardly facing back-up surface 11a which, in this embodiment, is flat or planar. The platform 11 extends laterally between the sides of a frame 12 of the apparatus 10 at approximately the central portion thereof. A main guide rod 13 and an auxiliary guide rod 14 extend laterally parallel to each other above the back-up surface 11a of the platform 11 and are supported, at their ends, in the sides of the frame 12. A belt drive section 16 is mounted on one side of the frame 12 in the vicinity of the guide rods 13 and 14, and includes a reversible electric motor 17 and a pulley 18 coupled to the motor shaft (Figure 4). Another pulley 19 is suitably mounted on the opposite side of the frame 12 adjacent to the guide rods 13 and 14, and a drive belt 21 runs around the pulleys 18 and 19 and laterally across the frame 12 therebetween parallel to the guide rods 13 and 14. A carriage 30 is slidably mounted on the main guide rod 13 and ends of the drive belt 21 are suitably secured to the carriage 30, so that it can be transported in directions indicated by the arrows A and B, respectively, and which are parallel to the axis of the guide rod 13 in response to the operation of the motor 17 in one direction or the other. Referring now to Figure 6, it will be seen that a roller support member 32 is mounted at the underside of the carriage 30 for rocking relative to the carriage 30 about a pivot pin 31. A roller 33 having a relatively narrow peripheral surface or rim is rotatable freely about a shaft or axle 33a carried by the support member 32, with the axis of the shaft 33a extending perpendicular to the directions A and B. A bore 34 extends vertically through the carriage 30 above the roller support member 32 at a location spaced from the pivot 31, and a follower pin 35 extends upwardly from the roller support member 32 substantially axially through the bore 34. The follower pin 35, which may be in the form of a flat-head screw, includes a shaft portion 35a and a head 35b with a tapering underside. A helical compression spring 36 extends around the follower pin 35 and bears, at its opposite ends, against a downwardly facing shoulder 34a within the bore 34 for urging the latter downwardly, and thereby pressing the roller 33 against the back-up surface 11a. An actuating plate 37 is mounted on top of the carriage 30 for limited slidable movements relative to the latter parallel to the directions A and B. For example, as shown, the actuating plate 37 may be formed with an elongated slot 38 having a relatively wide end portion 38a and a relatively narrow major portion 38b which opens into the wide end portion 38a at diverging side edges 38c (Figure 11). The relatively narrow major portion 38b of the slot 38 is laterally dimensioned slidably to receive a guide pin 38d mounted on the top of the carriage 30, and also slidably to receive the shaft portion 35a of the follower pin 35. Thus, the actuating plate 37 is guided in its limited slidable movements relative to the carriage 30 between a first position (Figures 6 and 9) and a second position (Figures 7 and 8). The shaft 35a of the follower pin 35 is longitudinally dimensioned so that, when the actuating plate 37 is in its second position (Figures 7 and 8) for locating the follower pin 35 within the relatively narrow portion 38b of the slot 38, the tapering underside of the head 35b of the follower pin 35 rides on the top surface of the plate 37 and thereby raises the roller support member 32 against the force of the spring 36 for holding the roller 33 away from the back-up surface 11a. On the other hand, when the actuating plate 37 is moved to its first position (Figures 6 and 9), the shaft of the follower pin 35 moves into the relatively wide end portion 38a of the slot 38, or at least into the region between the diverging side edges 38c of the slot (Figure 10), so as to permit the follower pin 35 to move downwardly under the influence of the spring 36 acting on the support member 32, so the roller 33 is pressed against the back-up surface 11a by the force of the spring 36. The actuating plate 37 is formed with an upstanding rim 37a at the end thereof adjacent to the relatively wide end portion 38a of the slot 38. The carriage 30 has a light shield 39 directed upwardly from its top surface (Figures 6 to 9) at the end of the carriage remote from the upstanding rim 37a. Stop members 22a and 22b are slidably mounted on the opposite end portions, respectively, of the auxiliary guide rod 14 and are suitably secured, as by set screws (not shown), at adjusted positions along the respective end portions of the guide rod 14. The stop members 22a and 22b are selectively engageable by the upstanding rim 37a on the actuating plate 37, for example, as in Figures 6 and 7 and in Figures 8 and 9, respectively, and are effective to displace the actuating plate 37 from one to the other of its first and second positions on the carriage 30, as hereinafter described in detail. Photo-sensing devices 23a and 23b are similarly adjustably mounted on the opposite end portions of the auxiliary guide rod 14. As shown in Figure 5 with respect to the photo-sensing device 23a, each of the photo-sensing devices 23a and 23b includes a light source 24 and a photo cell 25 disposed at opposite sides of the path of travel of the light shield 39 on the carriage 30 so that the light path from the source 24 to the respective photo-cell 25 is interrupted by the shield 39 at a predetermined position of the carriage 30, and hence of the roller 33, with respect to the photo-sensing device 23a or 23b. In the illustrated embodiment, the photo-sensing devices 23a and 23b are located at the same predetermined distances from the stop members 22a and 22b, respectively, and are preferably adjustable with the stop members 22a and 22b along the respective end portions of the guide rod 14. Moreover, the distance between each of the photo-sensing devices 23a and 23b and the respective stop member 22a or 22b is approximately equal to the distance between the light shield 39 and the upstanding rim 37a. Moreover, as viewed in Figure 4, each of the photo-sensing devices 23a and 23b is disposed to the left of the respective stop member 22a or 22b. When, in the course of movement of the carriage 30 in the direction A or B, either one of the photo-sensing devices 23a and 23b detects the arrival of the carriage 30 at the respective positions along the guide rod 13, by sensing that the light shield 39 on the carriage 30 interrupts the passage of light from the respective light source 24 to the respective photo cell 25, the direction of operation of the reversible electric motor 17 is reversed so as to drive the carriage 30 along the guide rod 13 in the opposite direction B or A. Referring now to Figure 5, it will be seen that, in the embodiment, the sheets 1 and 3 are transported in contact with each other in a predetermined direction of sheet travel across the back-up surface 11a, that is, in a direction perpendicular to the directions of the movements of the roller 33 with the carriage 30 along the guide rod 13. As shown, the photo-sensitive sheet 1 may be in the form of a web which is unwound from a supply reel 41 and then lead under a guide roller 42 into a horizontal run extending between feed rollers 46a and 46b at the entry side of the platform 11. A cathode-ray tube 43 is disposed below the horizontal run of the web between the guide roller 42 and the feed rollers 46a and 46b to provide a light image corresponding to a picture to be developed and which is emitted from a display surface 43a through a multi-lens array 44 closely underlying the photo-sensitive sheet material. Thus, the light of the image displayed by the cathode-ray tube 43 is projected by the lens array 44 through the light transmitting base of the web of photo-sensitive sheet material for irradiating the microcapsule-containing coating 2 which, in the illustrated embodiment is at the top thereof. The feed rollers 46a and 46b transport the web across the back-up surface 11a of the platform 11 in the predetermined direction perpendicular to the directions of the movements of the roller 33 with the carriage 30 along the guide rod 13. After travelling across the back-up surface 11a, the web passes between exit feed rollers 46c and 46d and then over a guide roller 45 to a take-up reel 47 on which the web is rewound. A developing paper supply tray 48 is located above the path of travel of the web of photo-sensitive sheet material between the guide roller 42 and the entry feed rollers 46a and 46b, and contains a stack of sheets 3 of developing paper which are suitably transported therefrom one-by-one, for example, by means of a roller 49, so as to be fed into the nip between the entry feed rollers 46a and 46b in superimposed relation with the previously irradiated or exposed photo-sensitive sheet material. The sheet 3 of developing paper is transported with the underlying photo-sensitive sheet material across the back-up surface 11a, and then between the exit feed rollers 46c and 46d, whereupon the developing paper sheet 3 is suitably stripped or separated from the web of photo-sensitive sheet material and received by a take-up tray 50. In the developing apparatus 10, the sheets 3 of developing paper and the web of photo-sensitive sheet material are transported together across the back-up surface, as by the entry feed rollers 46a and 46b and the exit feed rollers 46c and 46d, in an intermittent manner so as to alternate periods of incremental movement and of rest, respectively. Following each incremental movement of a sheet 3 of developing paper together with the web through a predetermined small distance, the drive motor 17 is suitably operated to effect a single reciprocating movement of the carriage 30 along the guide rod 13, as hereinafter described in detail. The operation of the developing apparatus 10 will now be described in detail: As the web of the photo-sensitive sheet material is transported intermittently from the supply reel 41 and across the back-up surface 11a, the photo-sensitive sheet material is irradiated in a similar step-by-step manner by the cathode-ray tube 43. In other words, during each period of rest of the intermittently transported web of photo-sensitive sheet material, the electron beam or beams of the cathode-ray tube 43 scan a relatively narrow, laterally extending stripe-like area of the display surface 43a so as to irradiate a similarly narrow, stripe-like area extending across the web. During the next period of incremental movement of the web, the photo-sensitive sheet material is advanced a distance corresponding to the pitch or width of the stripe-like area that has been irradiated, whereupon, during the next period of rest, a successive stripe-like area of the web is irradiated with a corresponding stripe-like area of the display surface 43a. In such step-by-step manner, a portion of the web is irradiated by a light image corresponding to the colour picture to be developed. Following such irradiation, a sheet 3 of developing paper is transported from the tray 48 onto the web so as to be registered with the portion of the latter which has been irradiated with the light image. Thereafter, as the web and a sheet 3 of developing paper superimposed thereon in registration with the portion irradiated with a light image of the colour picture to be developed are incrementally transported across the back-up surface 11a, the carriage 30 is reciprocated once along the guide rod 13 during each period of rest of the transported sheets 1 and 3. During such reciprocatory movement of the carriage 30 in one direction, for example, in the direction of the arrow A in Figure 4, the roller 33 is urged towards the back-up surface 11a. Thus, the sheet 3 of developing paper and the web of photo-sensitive sheet material in contact with each other between the roller 33 and the back-up surface 11a are thereby pressed together along a relatively narrow stripe-like area corresponding to the rolling path of the narrow periphery of the roller 33. During the return movement of the carriage 30, for example, in the direction of the arrow B, and during which the incremental transport of the sheet 3 of developing paper and the web across the back-up surface 11a is effected, the roller 33 is moved away from the back-up surface 11a. The manner in which the foregoing movements of the roller 33 are effected will now be more specifically described with reference to Figures 6 to 9. Assuming that the carriage 30 is nearing the end of its operative movement in the direction of the arrow A, with the actuating plate 37 in its first position so as to permit the spring 36 to urge the roller 33 against the back-up surface 11a with the sheets 1 and 3 therebetween, the upstanding rim 37a on the actuating plate 37 comes into contact with the stop member 22a adjustably fixed on the guide rod 14. Thereafter, the concluding movement of the carriage 30 in the direction of the arrow A by the operation of the drive motor 17 is accompanied by the shifting of the actuating plate 37 to its second position relative to the carriage 30, as in Figure 7, with the result that the tapering undersurface of the head 35b of the follower pin 35 cooperates with the diverging edges 38c of the slot 38 for raising the follower pin 35, and thereby upwardly rocking the roller support member 32. Thus, the roller 33 is moved upwardly away from the back-up surface 11a so as to free or clear the contacting sheets 1 and 3 therebetween. Moreover, when the carriage 30 attains the position shown in Figure 7, the light shield 39 on the carriage 30 intercepts the light path of the photo-sensing device 23a and, as a result thereof, the direction of operation of the motor 17 is reversed. Thus, upon attaining the position shown in Figure 7, the carriage 30 is thereafter moved or driven in the return direction indicated by the arrow B in Figure 8 with the roller 33 being maintained in its raised position away from the back-up surface 11a in accordance with the actuating plate 37 remaining in its second position relative to the carriage 30. As earlier noted, an incremental movement of the sheets 1 and 3 is suitably effected by the feed rollers 46a to 46d during each interval when the roller 33 is held away from the back-up surface 11a, that is, during each return movement of the carriage 30 in the direction of the arrow B. As the carriage 30 nears the end of its return movement in the direction of the arrow B, the upstanding rim 37a on the actuating plate 37 comes into contact with the adjustably fixed stop member 22b, for example, as shown in Figure 8. Therefore, during the final further movement of the carriage 30 in the direction of the arrow B, the engagement of the rim 37a with the stop member 22b causes displacement of the actuating plate 37 to its first position relative to the carriage 30, as shown in Figure 9. Such displacement of the actuating plate 37 to its first position, as in Figures 9 and 10, releases the head 35b of the follower pin 35 from engagement with the edges of the relatively narrow slot portion 38b, with the result that the spring 36 can move the follower pin 35 and the roller support member 32 downwardly, and thereby urge the roller 33 against the back-up surface 11a with the sheets 1 and 3 therebetween. The final movement of the carriage 30 to the position shown in Figure 9 also causes the shield 39 thereon to intercept the light path in the photo-sensing device 23b and, in response thereto, the motor 17 is reversed for causing the drive belt 21 thereafter to drive the carriage 30 in the direction of the arrow A in Figures 4 and 6 from the position shown in Figure 9 to the position shown in Figure 7. During such movement of the carriage 30 in the direction of the arrow A from the position shown in Figure 9 at least to the position shown in Figure 6, the roller 33 is urged against the back-up surface 11a, so that the roller 33 applies pressure to the contacting sheets 1 and 3 along a laterally extending stripe-like area extending across the contacting sheets 1 and 3, and corresponding, in width, to the axial width of the peripheral surface of the roller 33. It will be appreciated that, during such application of pressure by the roller 33 as the carriage 30 moves from the position of Figure 9 to the position of Figure 6, the contacting sheets 1 and 3 remain at rest on the back-up surface 11a. At the completion of the operative movement of the carriage 30 in the direction of the arrow A from the position of Figure 9 to the position of Figure 6, the rim 37a again engages the adjustably fixed stop member 22a for moving the actuating plate 37 to its second position, and thereby raising the roller 33 away from the back-up surface 11a in response to the final movement of the carriage 30 to the position shown in Figure 7. Moreover, as previously noted, when the carriage 30 attains the position of Figure 7, the shield 39 intercepts the light path in the photo-sensing device 23a for causing another reversal of the direction of drive of the carriage 30. The above-described movements of the carriage 30 and of the roller 33 mounted thereon are cyclically repeated as the sheets 1 and 3 are transported step-by-step. Thus, the roller 33 applies pressure along successive stripe-like areas extending across the contacting sheets 1 and 3 as they are transported intermittently across the back-up surface 11a. Thereby a colour picture irradiated on the photo-sensitive sheet 1 by the cathode-ray tube 43 is printed or developed on a sheet 3 of the developing paper which is then stripped or separated from the sheet 1 and ejected into the tray 50. The roller 33 for pressing together the sheets 1 and 3 moves with the carriage 30 in the directions of the arrows A and B. Moreover, the width of the peripheral surface of the roller 33 at which it exerts its pressing action against the sheets 1 and 3 is relatively small in comparison to the distance across the sheets 1 and 3. Therefore, the contact area of the roller 33 with the sheets 3 and 1 against the back-up surface 11a is very small, with the result that the requisite contact pressure of 30 to 40 kg/mm² for rupturing the unhardened microcapsules of the photo-sensitive sheet 1, and for ensuring the reliable transfer of the released pigment precursors into adequate contact with the developing substances of the sheet 3 of developing paper can be achieved by means of a relatively small and light helical compression spring 36. Since it is unnecessary to apply a large force for urging the roller 33 towards the back-up surface 11a, the structure of the apparatus 10 can be simplified and made compact. Moreover, since the roller 33 carried by the rockable roller support member 32 is in rolling contact with the superimposed sheets 1 and 3 against the back-up surface 11a during the operative movement of the carriage 30, the roller 33 performs its necessary function of rupturing the unhardened microcapsules and of transferring the released pigment precursors to sheet 3 of the developing paper in a smooth and relatively quiet manner. The stop members 22a and 22b and the photo-sensing devices 23a and 23b can be adjusted along the auxiliary guide rod 14, so it is possible to change the width of the sheets 1 and 3 across which the roller 33 exerts pressure against the back-up surface 11a, and hence the width of the area at which a picture is printed or developed. In order to appreciate the advantage of such adjustment of the stop members 22a and 22b and the photo-sensing devices 23a and 23b, it is to be noted that, if the sheet 3 of developing paper extends over opposite side portions of the photo-sensitive sheet 1 which have not been irradiated, and the sheets 1 and 3 are pressed together by the roller 33 across the entire width of the sheets 1 and 3, the opposite side margins of the sheet 3 of developing paper extending beyond the developed colour picture would be developed black. In the described embodiment, the back-up surface 11a of the platform 11 is flat, and the contact area of the roller 33 with the sheets 1 and 3 against the back-up surface 11a is made small by providing the peripheral surface of the roller 33 with a relatively small axial width. However, if desired, and as shown specifically in Figure 5A, a platform 11′ employed in place of the platform 11 may be provided with a convex back-up surface 11′a having a rectilinear generatrix extending parallel to the direction of movement of the roller 33 with the carriage 30 along the guide rod 13. Such arrangement illustrated in Figure 5A further reduces the contact area of the roller 33 with the sheets 1 and 3 against the back-up surface 11′a so that even a smaller force can be exerted by the spring 36 for obtaining the requisite contact pressure between the sheets 1 and 3. The foregoing advantage of the arrangement shown in Figure 5A can be similarly obtained with the flat back-up surface 11a of Figure 5 by providing the roller 33 with a convex peripheral surface. Of course, when thus reducing the contact area of the roller 33 with the sheets 1 and 3 against the back-up surface 11a or 11′a, each incremental movement of the sheets 1 and 3 during the intermittent transport thereof across the back-up surface is correspondingly reduced.

Claims: An apparatus (10) for developing a picture on a sheet (3) of developing paper from a photo-sensitive sheet (1) of a type which develops said picture upon the pressing together of the sheet (3) of developing paper and the photo-sensitive sheet (1), the apparatus comprising: means (11) defining a back-up surface (11a); means (46) for transporting the sheet (3) of developing paper and the photo-sensitive sheet (1) in contact with each other in a predetermined direction of sheet travel across the back-up surface (11a); a rotatable member (33) disposed in opposing relation to the back-up surface (11a) and having an axis of rotation extending parallel to said predetermined direction of sheet travel; means (30) mounting the rotatable member (33) for bodily movements towards and away from the back-up surface (11a) and parallel to the back-up surface (11a) in directions perpendicular to said predetermined direction of sheet travel; and means (17) for transporting the rotatable member (33) relative to the back-up surface (11a) in one of said directions perpendicular to said predetermined direction of sheet travel while urging the rotatable member (33) towards the back-up surface (11a) with the sheet (3) of developing paper and the photo-sensitive sheet (1) being in contact with each other between the rotatable member (33) and the back-up surface (11a) so as to be pressed together thereby; characterised in that the rotatable member is a rotatable roller (33); the means (46) for transporting the sheets (1, 3) operates intermittently so as to alternate periods of incremental movement and of rest, respectively, of the sheets (1, 3); and the means (17) for transporting the rotatable roller (33) operates, during each of the periods of rest, to transport the rotatable roller (33) in said one direction perpendicular to said direction of sheet travel while urging the rotatable roller (33) towards the back-up surface (11a), whereupon the means (17) for transporting the rotatable roller (33) operates to return the rotatable roller (33) in the other of said directions perpendicular to said direction of sheet travel; and the apparatus comprises means (35, 36, 37) for moving the rotatable roller (33) away from the back-up surface (11a) during each of the periods of incremental movement of the sheets (1, 3) and during the return of the rotatable roller (33) in said other direction perpendicular to said direction of sheet travel. Apparatus (10) according to claim 1, further comprising means (43) for irradiating the photo-sensitive sheet (1) with a light image of the picture to be developed in advance of said pressing together of the sheet (3) of developing paper and the photo-sensitive sheet (1). Apparatus (10) according to claim 2, wherein the photo-sensitive sheet (1) has a surface comprised of photo-sensitive microcapsules (2Y, 2C, 2M) which are selectively hardened by the light image. Apparatus (10) according to claim 1, wherein the rotatable (33) has a peripheral surface of a width which is small relative to a distance the rotatable roller (33) is transported in said one direction perpendicular to said predetermined direction of sheet travel. Apparatus (10) according to claim 4, wherein the back-up surface (11a) is flat. Apparatus (10) according to claim 1, wherein the back-up surface (11′a) is convex and has a rectilinear generatrix extending parallel to said one perpendicular direction in which the rotatable roller (33) is transported so that the rotatable roller (33) and the back-up surface (11′c) press together the sheet (3) of developing paper and the photosensitive sheet (1) at a small contact area. Apparatus (10) according to claim 1, wherein the means (17) for transporting the rotatable roller (33) includes reversible drive means (17) for transporting the rotatable roller (33) in said one direction and said other direction perpendicular to said direction of sheet travel, and means (23a, 23b) for detecting opposite end positions of the rotatable roller (33) during said transporting of the rotatable roller (33) in said one direction and said other direction, respectively, and for reversing the drive means (17) upon detection of each of the opposite end positions. Apparatus (10) according to claim 7, further comprising means (22a, 22b) for adjusting the location of at least one of the opposite end positions. Apparatus (10) according to claim 7, wherein the means (30) mounting the rotatable roller (33) includes guide means (13) extending parallel to said directions perpendicular to the direction of sheet travel, a carriage (30) movable along the guide means (13), a roller support member (32) having the rotatable roller (33) rotatable thereon and being mounted on the carriage (30) for said movement of the rotatable roller (33) towards and away from the back-up surface (11a), and spring means (36) acting on the roller support member (32) for said urging of the rotatable roller (33) towards the back-up surface (11a); and wherein the means (35, 36, 37) for moving the rotatable roller (33) away from the back-up surface (11a) includes actuating means (35, 37 on the carriage (30) and the roller support member (32) having an engaged condition for moving the rotatable roller (33) away from the back-up surface (11a) against the force of said spring means (36) and a disengaged condition in which said spring means (36) is free to urge the rotatable roller (33) towards the back-up surface (11a), and means (38) for establishing said disengaged and engaged conditions of the actuating means (35, 37) in response to final transporting movements of the rotatable roller (33) in said one direction and said other direction, respectively, to the respective opposite end positions. Apparatus (10) according to claim 1, further comprising means (23a, 23b) for detecting a position of the rotatable roller (33) in said movements thereof in said directions perpendicular to said direction of sheet travel. Apparatus (10) according to claim 10, wherein the means (30) mounting the rotatable roller (33) includes guide means (13) extending parallel to said directions perpendicular to said direction of sheet travel, a carriage (30) reciprocally movable along the guide means (13), and a roller support member (32) rotatably supporting the rotatable roller (33) and connected with the carriage (30) for permitting said movements of the rotatable roller (33) towards and away from the back-up surface (11a); and wherein the means (23a, 23b) for detecting a position of the rotatable roller (33) includes photo-sensor means (23a, 23b), and a light shielding member (39) on the carriage (30) for interrupting a light beam otherwise received by the photosensor means (23a, 23b) when the rotatable roller (33) is in the position to be detected. Apparatus (10) according to claim 11, further comprising spring means (36) acting on the roller support member (32) for said urging of the rotatable roller (33) towards the back-up surface (11a); and means (37, 35) for moving the rotatable roller (33) away from the back-up surface (11a) including an actuating plate (37) mounted on the carriage (30) for limited slidable movements relative thereto in said directions perpendicular to said direction of sheet travel between first and second positions, a follower member (35) extending from the roller support member (32) and engaging the actuating plate 37, the actuating plate (37) and follower means (35) cooperating to permit the spring means (36) to move the rotatable roller (33) towards the back-up surface (11a) when the actuating plate (38) is in said first position thereof, and to displace the roller support member (32) for moving the rotatable roller (33) away from the back-up surface (11a) when the actuating plate (38) is in said second position thereof, and a stop member (22a, 22b) mounted adjacent to the photo-sensor means (23a, 23b) and being engageable with the actuating plate (37) for moving the actuating plate (37) from one to another of said first and second positions relative to the carriage (32) during a final increment of movement of the carriage (32) for disposing the rotatable roller (33) in said position of the rotatable roller (33) to be detected by the photo-sensor means (23a, 23b). Apparatus (10) according to claim 12, wherein the photo-sensor means (23a, 23b) and the stop member (22a, 22b) are adjustable along a guide means (14).

Inventors: YUI YASUJI C O PATENTS DIVISIO, YUI, YASUJI C/O PATENTS DIVISION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1988
Main classification: G03F7
IPC codes: G03F7, G03D13