SPECIFIC CASSETTE SELECTION APPARATUS

Abstract: In a copying machine having a plurality of paper feeding cassettes (13) removably mounted thereon and having a specific copying function such as an automatic both-side copying function, a continuous page copying function, etc., in addition to normal copying functions, the present invention discloses a specific cassette selection apparatus which det­ ects the size of copying paper housed in each paper feeding cassette (13) when the specific copying function is selected, and selects a state in which copying paper can be fed from the paper feeding cassette (13) for paper of the size which can be used for such specific copying function selected.

Description: BACKGROUND OF THE INVENTION The present invention relates to a copying machine having a plurality of paper feeding cassettes, and more particularly to an apparatus capable of automatically selecting, out of a plurality of paper feeding cassettes, a proper cassette for paper of the size which can be used for a specific function such as a continuous page copying function, an automatic both-side copying function, etc. when such function is selected. Recently, the demand for a multi-function copying machine has become strong. As a part of such demand, there has been proposed a copying machine provided with a continuous page copying function capable of continuously copying each page of a book document without movement of the book document, or an automatic both-side copying func­ tion capable of automatically copying images on the both sides of a piece of paper without manual paper removal and insertion. Such copying machine is usually provided with a con­ tinuous page copying mode selection key or an automatic both-side copying mode selection key. However, a paper feeding cassette to be used in a selected mode has to be selected by operating a cassette selection key and such cassette selection operation has to be made independently from the mode selection operation. Therefore, after a mode selection key has been operated, the cassette selec­ tion key is operated to select a proper paper feeding cassette and the print key is then operated to carry out the continuous page copying function or the automatic both-side copying function properly. As to a copying machine having a continuous page copying function, there has been proposed a machine of which continuous page copying function can be fulfilled with paper of a size of 8.5 inches × 11 inches only (1 inch equals 25.4 mm). In such machine, the mode selection key is operated to select the continuous page copying mode, and the cassette selection key is operated to select the cassette housing paper of 8.5 inches × 11 inches. The print key is then operated to carry out the continuous page copying operation. In the former copying machine above-mentioned, al­ though certain restrictions are imposed on the size of paper which can be used for the continuous page copying function or the automatic both-side copying function, the print key can be operated regardless of the size of paper selected. Therefore, an erroneous selection of a paper feeding cassette results in an error copy. Further, when a proper paper feeding cassette has not been selected after the function above-mentioned was selected, it is required to select a proper cassette by operating the cassette selection key. In the latter copying machine above-mentioned, the occurrence of error copy can be securely prevented when the continuous page copying mode is selected. However, selection of a proper cassette is always required. SUMMARY OF THE INVENTION It is an object of the present invention to provide a specific cassette selection apparatus capable of perform­ ing a specific copying operation without producing an error copy. It is another object of the present invention to provide a specific cassette selection apparatus which does not require an operation of selecting a proper paper feed­ ing cassette for a specific copying operation. An embodiment of the copying machine in accordance with the present invention comprises identification means, specific copying mode selection means and paper feeding cassette selection means. The identification means is disposed for identifying the size of paper housed in each paper feeding cassette. The specific copying mode selection means is disposed for selecting a state in which a specific copying operation can be performed. The paper feeding cassette selection means is disposed for selecting a proper cassette for paper of the size which can be used for carrying out a specific copying operation, based on signals supplied from the specific copying mode selection means and the identi­ fication means. The paper feeding cassette selection means can be so arranged as to display a paper feeding cassette to be properly selected, if such cassette has not been set. The specific copying operation may be a continuous page copying operation or an automatic both-side copying operation. According to the specific cassette selection appara­ tus arranged as above-mentioned, the identification means identifies the size of paper housed in each paper feeding cassette and when the state in which the specific copying operation can be performed, is selected by operating the specific copying mode selection means, the paper feeding cassette selection means can select a proper cassette for paper of the size which can be used for carrying out such specific copying operation, based on signals supplied from the specific copying mode selection means and the identi­ fication means. When the paper feeding cassette selection means is adapted to display a paper feeding cassette to be properly selected if such cassette has not been set, this means can indicate the necessity of mounting a proper cassette to be selected, by displaying such cassette. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a copying machine having a specific cassette selection apparatus in accordance with the present invention. FIG. 2 is a flowchart illustrating a specific cas­ sette selection operation. FIG. 3 illustrates the specific cassette selection operation. FIG. 4 is a schematic view showing the inner mecha­ nism of a copying machine having an automatic both-side copying function. FIG. 5 is a schematic view of showing the inner mech­ anism of a copying machine having a continuous page copying function. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 4 is a schematic view showing the inner mecha­ nism of a copying machine having an automatic both-side copying function. A copying machine body 1 is provided at the top thereof with a contact glass 11 and an original cover 12 and in the inside thereof with an optical system 2, a copy treatment section 3 and a conveying section 4. The optical system 2 has a light source 21, mirrors 22, 23, 24, a lens 25 and a mirror 26. The light source 21 illuminates an original document (not shown) placed on the contact glass 11. The light reflected from the origi­ nal document is guided to the copy treatment section 3 through the mirrors 22, 23, 24, the lens 25 and the mirror 26. In the copy treatment section 3, a photoreceptor drum 31 rotatable in one direction is surrounded by a charger 32, a developing device 33, a transfer charger 34, a separation charger 35 and a cleaner 36 in this order. On the surface of the photoreceptor drum 31 uniformly charged by the charger 32, a static latent image corresponding to the image of the original document is formed by guiding the light reflected from the original document onto said sur­ face. The static latent image is then developed into a toner image by the developing device 33. The transfer charger 34 then transfers the toner image to a copying paper P. After the separation charger 35 has peeled the copying paper P from the surface of the photoreceptor drum 31, the toner remaining on the surface of the photorecep­ tor drum 31 is collected by the cleaner 36. The conveying section 4 comprises a normal paper conveying unit 4a which includes paper feeding rollers 41 each for feeding copying paper P sheet by sheet from each of paper feeding cassettes 13 removably mounted on the copying machine body 1 at predetermined positions thereof, paper feeding passages 42, resist rollers 43, conveying rollers 44, a conveying belt 45, a heat-fixation device 46, conveying rollers 47 and paper discharging rollers 48, and a feedback paper conveying unit 4b which includes a changeover pawl 49 between the conveying rollers 47 and the discharging rollers 48, a first guide space 50 in a curved form, conveying rollers 51, a second guide space 52, a secondary paper feeding roller 53, an intermediate tray 54 and a paper feeding passage 55. When only one image forming operation is to be per­ formed on a piece of paper P, paper conveyance is carried out by the paper conveying unit 4a alone. When two or more image forming operations are to be performed on a piece of paper P, paper conveyance is alternately carried out by the paper conveying units 4a and 4b. Fig. 1 is a block diagram of an embodiment of the specif­ ic cassette selection apparatus in accordance with the present invention. An identification unit 60 which iden­ tifies the size of paper housed in a mounted paper feeding cassette (which is constituted, for example, by a magnet and a reed switch, the relative positions of which are previously set correspondingly to the types of paper feed­ ing cassettes), an automatic both-side copying mode selec­ tion key 61, a print key 62, and a cassette selection key 63 are connected to a microcomputer 65 through an input port 64. A control signal from the microcomputer 65 is supplied, through an output port 66, to clutch drive units 67 for controlling the drive of the respective paper feed­ ing rollers 41, and display drive units 68, 69, 70. Out­ put signals from the display drive units 68, 69, 70 are respectively supplied to a paper size display 71, a paper feeding stage display 72 and a copy-ready state display 73. Fig. 2 is a flowchart illustrating the operation of the specific cassette selection apparatus. At the step (1), it is judged whether or not the automatic both-side copying mode has been selected, that is, whether or not the automatic both-side copying mode selection key 61 has been operated. When it is judged at the step (1) that the automatic both-side copying mode has not been selected, the judgment at the step (1) is repeated until it is judged at the step (2) that the print key 62 has been operated. When it is judged at the step (2) that the print key 62 has been operated, paper is fed from a paper feeding cassette se­ lected at this point and a series of copying operations are carried out at the step (3). Then, judgments and processings are carried out again at steps on and after the step (1). When it is judged at the step (1) that the automatic both-side copying mode has been selected, it is judged, based on a signal from the identification unit 60, at the step (4) whether or not there is mounted a paper feeding cassette for paper of the size which can be used in the automatic both-side copying mode (hereinafter referred to as a specific cassette). When it is judged that the spe­ cific cassette has been mounted, the paper size display 71 displays the size of paper housed in the specific cassette at the step (5). At the step (6), the feeding paper stage display 72 displays the paper feeding stage on which the specific cassette is mounted. At the step (7), the corre­ sponding clutch drive unit 67 then becomes ready to trans­ mit a driving force to the corresponding paper feeding roller for the paper feeding stage on which the specific cassette is mounted. At the step (8), the copy-ready state display 73 displays a copy-ready state. At the step (9), it is waited until the print key 62 is operated and at the step (10), a series of automatic both-side copying operations are carried out. Then, judgments and process­ ings are carried out again at steps on and after the step (1). When it is judged at the step (4) that the specific cassette has not been mounted, the paper size display 71 flickeringly displays the size of paper housed in the specific cassette at the step (11). At the step (12), the copy-ready state display 73 displays a copy-impossible state. Then, judgments and processings are carried out again at steps on and after the step (4), In brief, when the automatic both-side copying mode is selected (FIG. 3-B) with the specific cassette mounted on any of the paper feeding stages (for example, as shown in FIG. 3-A in which the paper feeding cassette for paper of B5 size is selected and mounted on the lowest stage), the specific cassette is automatically selected and the specific cassette selection state is displayed (for exam­ ple, as shown in FIG. 3-C in which the specific cassette for paper of A4 size is selected and mounted on the inter­ mediate stage). The copy-ready state is displayed (as shown in FIG. 3-C in which a copy ready lamp 73 incor­ porated in the print key 62 comes ON). When the specific cassette is not mounted on any of the paper feeding stages, the size of paper housed in the specific cassette is flickerlingly displayed and the copy-ready lamp 73 is switched off hereby informing the operator that the specific cassette should be mounted. Accordingly, when the specific cassette is mounted, the corresponding paper feeding stage is automatically selected, and when the specific cassette is not mounted, the copying operation cannot be carried out. This not only prevents the occurrence of error copy, but also elim­ inates the cassette selection operation when the specific cassette has been mounted. The following description will discuss the operation of the copying machine having the construction above­ mentioned. [I] When one image forming operation is to be per­ formed on a piece of paper P: In such case, the changeover pawl 49 is operated to guide the paper P sent from the conveying rollers 47 to the discharging rollers 48. On the paper P sent from a paper feeding cassette 13, there is formed a toner image corresponding to the image of an original document by the copy treatment section 3. The paper P passes through the heat-fixation device 46 to heat and fix the toner image. By the discharging rollers 48, the paper P is then dis­ charged to a receiving plate 14 attached to the copying machine body 1 at a predetermined position thereof. [II] When two or more image forming operations are to be performed on a piece of paper P: In such case, the changeover pawl 49 is operated to guide the paper P sent from the conveying rollers 47 to the first guide space 50. With this state, a toner image is formed on the paper P sent from a paper feeding cas­ sette 13, and then heated and fixed. Thereafter, the paper P is guided to the first guide space 50 by the con­ veying rollers 47 and the changeover pawl 49 and then continuously conveyed until the tip of the paper P is guided between the conveying rollers 51. In such state, conveying forces are respectively applied to the paper P by the conveying rollers 47 and the conveying rollers 51. Since the conveying speed of the conveying rollers 47 is equal to or higher than the con­ veying speed of the conveying rollers 51, no tension is applied to the paper P. The paper P can therefore pass through the first guide space 50 in a relatively free condition and is guided to the intermediate tray 54 through the second guide space 52. The paper P guided in the intermediate tray 54 is turned upside down because of the configuration of the second guide space 52. The secondary paper feeding roller 53 lets out the paper P, which passes through the paper feeding passage 55 and is guided again to the copy treatment section 3. A toner image is formed on the reverse side of the paper P. With the toner image heated and fixed by the heat-fixation device 46, the paper P is conveyed by the conveying rollers 47. The changeover pawl 49 reversely operated guides the paper P to the discharging rollers 48, which discharge the same to the receiving plate 14. The changeover pawl 49 is driven so as to be in the state reverse to that above-mentioned, i.e. the state for guiding the paper P to the discharging rollers 48, at a predetermined timing before the paper P is guided again to the changeover pawl 49 after the paper P has been entirely guided to the first guide space 50. As apparent from the foregoing, when there is select­ ed the automatic both-side copying mode requiring the use of a specific cassette, it is detected that the specific cassette for paper which can be used in the automatic both-side copying operation is mounted on any of the paper feeding stages, and the specific cassette is automatically selected. This prevents the occurrence of error copy and eliminates the specific cassette selection operation, thus improving the manipulation. The present invention should not be limited to the embodiment discussed hereinbefore, but can be applied to, for example, a copying machine having a continuous page copying function. Such copying machine is schematically shown in FIG. 5 in which a book document 82 turned up is set on a document placing base 81 having a main part of an endless belt, the document placing base 81 is reciprocally movable between the exposure position and the setting position, an optical system 83 illuminates the book docu­ ment in the course of the reciprocal motion of the docu­ ment placing base 81 so that a copied image is formed on paper P sent from a paper feeding cassette 84. In addition, the state in which the specific cassette is not mounted can be displayed by a special display de­ vice. Other modifications and variations of the present invention can be possible without departing from the scope of the invention as claimed.

Claims: 1. A copying machine (1) having a plurality of paper feeding cassettes (13) removably mounted on the body thereof, having means for copying an image of an original document on paper fed from a selected one of the paper feeding cassettes, and having specific copying mode selection means (61) for selecting a state allowing a specific copying operation requiring a specific paper, characterized in that a specific cassette selection apparatus (65) is provided determinating whether a paper feeding cassette containing the required paper can be selected, based on a signal from said specific copying mode selection means (61) and on a signal from means (60) for identifying the type of paper housed in each of said mounted cassettes, choosing such a cassette when mounted, and activating a paper size display (71) when such a cassette is not mounted. 2. A copying machine according to claim 1, wherein the specific copying operation is a continuous page copying operation. 3. A copying machine according to claim 1, wherein the specific copying operation is an automatic both-side copying operation.

Inventors: MIZUDE, KAZUHIRO, UJIHIRA, HIDEYUKI
Applicants: MITA INDUSTRIAL CO., LTD.
Application year: 1987
Main classification: G03G15
IPC codes: G03G15, B65H3