Printing paper protecting device

Abstract: The present invention is directed to the reliable prevention of soiling of a printing surface of printing paper and hence the elimination of waste of the printing paper and improvement in the printing quality. These are achieved by setting a paper stack (1) in a paper cassette (4) without touching the printing surface of the printing paper by the hand. A protecting plate (11) has a bending portion (11a) for separating the paper stack (1) and an open portion (11b) used for detecting that the paper is out. The protecting plate (11) is placed on the printing surface of the printing paper and is accommodated in the paper cassette (4) together with the paper stack (1).

Description: BACKGROUND OF THE INVENTION FIELD OF THE INVENTION: This invention relates to a printing paper protecting device which is capable of preventing the printing surface of printing paper, such as sublimation type printing paper, from being soiled during transportation or loading into the paper cassette. DESCRIPTION OF THE RELATED ART: Fig. 10 is a perspective view illustrating an example of how a stack of conventional printing paper is packaged. In Fig. 10, a paper stack 1, consisting of sheets of sublimation type printing paper (image-receiving paper), is loosely packaged by a packaging material 2. In other words, the first packaging material 2 has a size larger than that of the paper. The first packaging material 2 has a notch 2a and opening perforations 2b. Fig. 11 is a perspective view illustrating another example of how a stack of conventional sublimation type printing paper is packaged. In Fig. 11, the paper stack 1 is closely packaged by a second packaging material 3. The second packaging material 3 has an opening ribbon 3a. Fig. 12 is a plan view illustrating an example of a paper cassette for a printer. In Fig. 12, a side wall surface of a cassette body 4 is provided with positioning protrusions 4a which make contact with the rear end portion and two side surface portions of the printing paper. A pair of separating claws 5 are mounted in the cassette body 4 at positions where they make contact with the two corners of the forward end portion of the printing paper. The separating claws 5 separate the printing paper one by one when the paper is fed. Also, a pressure plate 6 on which the printing paper is placed is provided inside the cassette body 4. Springs 7 are provided between the cassette body 4 and the pressure plate 6 to urge the pressure plate 6 in the upward direction. How the paper stack 1 is set in the paper cassette will be explained. In the case of the paper stack 1 packaged by the first packaging material 2 shown in Fig. 10, first, the first packaging material 2 is unsealed from the notch 2a along the unsealing perforations 2b. Next, the forward end portion of the paper stack 1 is placed in the cassette body 4 at a predetermined position with the paper stack 1 being held by the hand over the remaining portion of the first packaging material 2, as shown in Fig. 13. Thereafter, the remaining portion of the first packaging material 2 is pulled out in the direction indicated by an arrow in Fig. 13. In the case of the paper stack 1 packaged by the second packaging material 3 shown in Fig. 11, since the paper stack 1 is closely packaged by the packaging material 3, it is difficult to pull out the second packaging material 3 in the manner shown in Fig. 13. Hence, after the unsealing ribbon 3a is removed, the whole of the second packaging material 3 is peeled off the paper stack 1. Then, the paper stack 1 is placed in the cassette body 4 at a predetermined position with the paper stack 1 being directly held by the hand, as shown in Fig. 14. The paper cassette with the paper stack 1 set therein is loaded in a printer body 8, as shown in Fig. 15. In the case of the conventional paper stack which is packaged by the first packaging material 2 shown in Fig. 10, since the paper stack 2 is loosely packaged, the end portion of the paper stack 1 may be out of true due to vibrations which occur during transportation or the like. To set such a paper stack 1 in true, the paper stack 1 must be handled by the hands, making the printing surface (the dyeing surface) of the printing paper soiled by the fats (fingerprints) or the like. In the case of the conventional paper stack packaged by the second packaging material shown in Fig. 11, since the paper stack 1 is closely packaged, the corner portions of the second packaging material 3 may be damaged, thus damaging the printing paper. Furthermore, the paper stack 1 must be handled directly by the hands, and this makes the printing surface of the printing paper soiled. Printing cannot be partially done on the printing paper whose printing surface is partially soiled. Consequently, the printing paper is wasted, and the printing quality deteriorates. A protecting device for a stack of film is known from EP-A-0 154 803 and includes a reinforcing plate placed upon the stack of film which is wrapped in packaging material for protection. The packaging material is provided to allow correct and easy positioning of the film in a cassette without soiling the film and to avoid damage during transportation. Upon insertion into a cassette, a part of the packaging material is removed so that the film can be in turn removed from the stack to supply the film for further use. A further prior art is EP-A-0 103 764 that is concerned with an apparatus whereby a film package containing a stack of films in a light-tight envelope can be suspended at one end in a light-tight chamber, there being means for cutting open the lower end of said envelope whilst it is in said light-tight chamber. A film receiving case can be coupled to the lower end of said light-tight chamber. A shutter between said chamber and said case is then opened to allow the stack of films to drop out of said chamber into the film receivng case. The film receiving case is then closed in a light-tight manner before being detached from said light-tight chamber. The light-tight envelope may have therein a bottom protective sheet that is adhesively secured to the inner surface of the envelope so that said protective sheet cannot drop out when the stack of films slide downwardly out of said envelope into the film receiving case. SUMMARY OF THE INVENTION An object of the present invention is to provide a printing paper protecting device which is capable of reliably preventing soiling of the printing surface of the printing paper so as to enhance the printing quality. This object is solved in accordance with the present invention by a printing paper protecting device including the features of Claim 1 or Claim 3. Thus according to a first aspect of the invention, there is provided a printing paper protecting device comprising a protecting plate placed on a printing surface of a paper stack consisting of a pile of printing paper; a removable packaging material enclosing said paper stack and said protecting plate; said protecting plate to be accommodated together with the paper stack in a paper cassette after removal of said packaging material; said protecting plate having a bending portion which is bent along an end portion of the paper stack, and a detecting portion which allows a sensor on a printer body to detect that the paper is used up. According to a second aspect of the invention there is provided a printing paper protecting device as in the first aspect of the present invention but wherein the protecting plate additionally comprises an engaging portion which engages with said paper cassette when said protecting plate is accommodated in said paper cassette in an edequate direction. According to a third aspect of the present invention there is provided a printing paper protecting device comprising a protecting plate placed on a paper stack consisting of a pile of printing paper, and a packaging material for closely packaging the paper stack and the protecting plate, said packaging material having an unsealing portion to expose one end portion of the paper stack and to allow the protecting plate to be removed from the packaging material before placing said one end portion of the paper stack in the paper cassette. In the printing paper protecting device provided according to the first aspect of the present invention, the paper stack is set in the paper cassette with the protecting plate laid on the printing surface thereof. Consequently the printing surface is not touched by hand. In the printing paper protecting device provided according to the second aspect of the present invention, the paper stack is set in the paper cassette with the protecting plate laid on the printing surface thereof. Consequently, the printing surface is not touched by the hand. Furthermore, since the engaging portion is engaged with the paper cassette, erroneous setting of the paper stack is prevented. In the printing paper protecting device provided according to the third aspect of the present invention, since the paper stack is closely packaged, shift of the paper stack during transportation is prevented. Also, damage to the paper stack during transportation is prevented by the reinforcing plate. Furthermore, when the paper stack is set in the paper cassette, the reinforcing plate is pulled out to generate a space between the paper stack and the packaging material and thereby facilitate removal of the packaging material. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of the essential parts of a printer illustrating how a printing paper protecting device provided according to the first and second aspects of the present invention is used; Fig. 2 is a perspective view illustrating how a paper stack and a protecting plate are set in a paper cassette; Fig. 3 is a sectional view illustrating the state in which the paper has run out in Fig. 1; Fig. 4 is an exploded perspective view illustrating how a plurality of paper stacks are laid on top of another; Fig. 5 is a side elevational view of Fig. 4; Fig. 6 is a perspective view illustrating how a paper stack is packaged using a printing paper protecting device provided according to the third aspect of the present invention; Fig. 7 is a plan view of a reinforcing plate of Fig. 6; Fig. 8 is a perspective view illustrating how the reinforcing plate is pulled out from the packaging material; Fig. 9 is a perspective view illustrating how the paper stack of Fig. 6 is set in the paper cassette; Fig. 10 is a perspective view illustrating an example of how a stack of conventional printing paper is packaged; Fig. 11 is a perspective view illustrating another example of how a stack of conventional printing paper is packaged; Fig. 12 is a plan view of an example of a paper cassette for a printer; Fig. 13 is a perspective view illustrating how the paper stack packaged by the packaging material of Fig. 10 is set in the paper cassette of Fig. 12; Fig. 14 is a perspective view illustrating how the paper stack packaged by the packaging material of Fig. 11 is set in the paper cassette of Fig. 12; and Fig. 15 is a perspective view illustrating how the paper cassette of Fig. 12 is loaded in the printer body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Identical or corresponding reference numerals in these figures to those in Figs. 10 through 15 represent similar or identical elements, and description thereof is omitted. Fig. 1 is a sectional view illustrating how a printing paper protecting device according to a first and second embodiments of the present invention is used. In Fig. 1, a protecting plate 11 is placed in the paper cassette together with the paper stack 1 in such a manner that it is in contact with the end surface of the paper stack 1 on which printing is done, i.e., the undersurface of the paper stack 1. The protecting plate 11 has a bending portion 11a which is bent along the end portion of the paper stack 1, and an open portion 11b serving as a detection portion. The bending portion 11a has an engaging portion 11c which engages with the positioning protrusion 4a. The printing paper protecting device according to this embodiment comprises the protecting plate 11. A sensor 12 for detecting the presence of the printing paper is provided on the printer body 8. The sensor 12 has an actuator 12a which contacts the printing paper. The aforementioned protecting plate 11 is packaged in a state wherein it is in contact with the paper stack 1 and such a package is carried from one place to another. As shown in Fig. 2, the protecting plate 11 is accommodated in the paper cassette together with the paper stack 1 after the package is completely removed therefrom. At that time, the printing surface (the undersurface) of the paper stack 1 is covered by the protecting plate 11, and soiling of the printing surface is thus prevented even when the paper stack 1 and the protecting plate 11 are handled by the hands. Furthermore, the protecting plate 11 reinforces the paper stack 1 against impacts which may be applied thereto during transportation and thereby prevents damage to the printing paper. Consequently, the printing quality is improved. The positioning protrusion 4a shown in Fig. 2 is slidable so that it can be adjusted to the size of the paper accommodated in the cassette. When all the printing paper has been fed out of the cassette, the actuator 12a falls into the open portion of the pressure plate 6, indicating that the paper has run out. In this embodiment, since the protecting plate 11 has the open portion 11b at a position where it opposes the open portion of the pressure plate 6, it does not hinder detection that the paper is out, as shown in Fig. 3. In a case where the cassette has a capacity which allows, for example, 100 sheets of paper to be accommodated therein while the single printing paper package contains, for example, 200 sheets of paper, the single protecting plate 11 is provided for the individual paper stack 1 which contains 100 sheets of paper, as shown in Figs. 4 and 5. In that case, when the paper stack 1 is set in the paper cassette, the paper stack 1 must be separated from the entire package shown in Fig. 4 one by one (which contains 100 sheets of paper). The bending portion 11a provided on the protecting plate 11 makes this separation easy. In Fig. 4, A represents a correct combination of the paper stack 1 and the protecting plate 11, and B represents an incorrect combination thereof. In a package in which many paper stacks 1 are laid on top of another, there is the possibility that the paper stack 1 and the protecting plate 11 are separated and set in the paper cassette in an incorrect combination B. The protecting plate 11 according to the present embodiment has the engaging portion 11c which is brought into engagement with the positioning protrusion 4a of the paper cassette, and thereby prevents it from being accommodated in the paper cassette in the incorrect combination B. Thus, the paper stack 1 and the protecting plate are not set in the cassette in an incorrect combination. Also, they are not set in an inside out. As a result, setting of the paper stack 1 in the paper cassette is facilitated, and workability is thus improved. In this embodiment, the mechanical type sensor 12 has been used. However, a reflection or transmission type optical sensor may also be employed. Furthermore, in this embodiment, the open portion 11b is provided as the detection portion. However, the detection portion is not limited to this but it may be altered according to the type of sensor 12. When, for example, a reflection type optical sensor is employed, a black marking which suppresses reflection of the light is provided on the protecting plate 11 as the detection portion. Furthermore, in this embodiment, the bending portion 11a is provided such that it runs along the rear end portion of the paper stack 1. However, it may be provided at other positions. Alternately, a plurality of bending portions 11a may be provided. Furthermore, the protecting plate 11 according to this embodiment has the engaging portion 11c which engages with the positioning protrusion 4a. However, the protecting plate 11 may be engaged with the other portion of the paper cassette or a protrusion provided on the paper cassette for exclusive use. Furthermore, there is no limitation to the material of the protecting plate 11. For example, a protecting plate 11 made of a plastic or thick paper may be used. Fig. 6 is a perspective view illustrating how a paper stack is packaged using the printing paper protecting device according to a third embodiment of the present invention. In Fig. 6, a reinforcing plate (protector) 21 is laid on top of the paper stack 1. The reinforcing plate 21 has a rib 21a which is bent along the end portion of the paper stack 1. The paper stack 1 and the reinforcing plate 21 are closely packaged by the second packaging material 3. The printing paper protecting device according to the present embodiment comprises the reinforcing plate 21 and the second packaging material 3. Fig. 7 is a plan view of the reinforcing plate 21 of Fig. 6. A length L 1 of the shorter side of the reinforcing plate 21 is the same as the length of the shorter side of the paper stack 1, and a length L 2 of the longer side of the reinforcing plate 21 is the same as that of the longer side of the paper stack 1. A length t of the rib 21 is equal to or less than the thickness of the paper stack 1. When the paper stack 1 packaged in the manner described above is to be set in the paper cassette, first, the end portion of the second packaging material 3 is unsealed by removing the unsealing ribbon 3a serving as the unsealing portion to expose the forward end portion (which is equal to or less than half of the entire length) of the printing paper. Next, as shown in Fig. 8, the reinforcing plate 21 is pulled out from the second packaging material 3 by pulling the rib 21a, whereby a space is generated between the second packaging material 3 and the paper stack 1. In that state, the forward end portion of the paper stack 1 is placed in the cassette body 4 at a predetermined position with the paper stack 1 being held by the hand over the remaining portion of the second packaging material 3, as shown in Fig. 9. Thereafter, the second packaging material 3 is pulled out in the direction indicated by the arrow. In the aforementioned printing paper protecting device, since the paper stack 1 is closely packaged by the second packaging material 3, the edges of the paper stack 1 remain in true during transportation. Furthermore, since the paper stack 1 is reinforced by the reinforcing plate 21 which is laid on top thereof, it is not damaged by impacts applied thereto during transportation or the like. Furthermore, since there is a space between the paper stack 1 and the second packaging material 3 in the package from which the reinforcing material 21 has been pulled out, the paper stack 1 can be set in the paper cassette without the whole of the second packaging material 3 being removed and without the paper stack 1 being directly held by the hand. Thus, soiling of the printing surface of the printing paper can be prevented, and the printing quality is thus improved. A reinforcing material 21 made of thick paper or a plastic may also be used. In the aforementioned embodiments, the sublimation type printing paper has been used. However, the printing paper is not limited to this but, for example, an OHP (Over Head Projector) film may be employed. As will be understood from the foregoing description, in the printing paper protecting device provided according to the first aspect of the present invention, the protecting plate is placed on the printing surface of the printing stack and is accommodated in the paper cassette together with the paper stack. Consequently, it is not necessary for the user to directly touch the printing surface, and soiling of the printing surface of the printing paper can thus be reliably prevented. As a result, waste of the printing paper can be eliminated, and the printing quality can be improved. Furthermore, since the protecting plate has the bending portion, the paper stack can be easily separated from the other paper stacks. Furthermore, since the protecting plate has the detecting portion, it does not hinder detection that the paper is out. The aforementioned protecting plate has the engaging portion which engages with the paper cassette when the protecting plate is suitably accommodated in the paper cassette. Thus, erroneous setting of the paper stack can be prevented. In the printing paper protecting device provided according to the third aspect of the present invention, the reinforcing plate is laid on the paper stack, and the paper stack and the reinforcing plate are closely packaged by the packaging material having the unsealing portion at one end portion thereof. Consequently, shift of or damage to the paper stack during transportation can be prevented, and the packaging material can be easily removed by pulling out the reinforcing plate. As a result, soiling of the printing surface of the printing paper can be reliably prevented, and waste of the printing paper can be eliminated while the printing quality can be improved.

Claims: A printing paper protecting device comprising a protecting plate (11) placed on a printing surface of a paper stack (1) consisting of a pile of printing paper; a removable packaging material enclosing said paper stack and said protecting plate; said protecting plate (11) to be accommodated together with the paper stack (1) in a paper casette (4) after removal of said packaging material; said protecting plate (11) having a bending portion (11a) which is bent along an end portion of the paper stack, and a detecting portion (11b) which allows a sensor (12) on a printer body (8) to detect that the paper is used up. A printing paper protecting device according to Claim 1 characterized in that the protecting plate (11) additionally comprises an engaging portion (11c) which engages with said paper cassette (4) when said protecting plate (11) is accommodated in said paper cassette (4) in an adequate direction. A printing paper protecting device comprising a protecting plate (21) placed on a paper stack (1) consisting of a pile of printing paper, and a packaging material (3) for closely packaging the paper stack (1) and the protecting plate (21), said packaging material (3) having an unsealing portion (3a) to expose one end portion of the paper stack (1) and to allow the protecting plate (21) to be removed from the packaging material before placing said one end portion of the paper stack in the paper cassette (4).

Inventors: KOUZAI FUMIO, ODA KEISUKE, KOUZAI, FUMIO, ODA, KEISUKE, KOUZAI, FUMIO, C/O MITSUBISHI DENKI K.K., ODA, KEISUKE, C/O MITSUBISHI DENKI K.K.
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1992
Main classification: B65H7
IPC codes: B65H1, B41J29, B41J13, B65H7