JP2018002356A - Image formation apparatus, sheet feeding tray stop position setting method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of the printing work by preventing no-sheet erroneous detection due to slipping-up of sheets and the like.SOLUTION: A stencil printing machine 1 includes: a sheet feeding roller 11a which feeds sheets P to a printing unit 6 side from a sheet feeding tray 10; a sheet presence detection sensor 58 which detects the presence/absence of sheets on the sheet feeding tray 10; a lifting mechanism 100 which lifts the sheet feeding tray 10 up/down; a storage unit 71 which stores position information (time t) of the position of the sheet feeding tray 10 at the time when the sheet presence detection sensor 58 detects no sheet in a case where the sheet feeding tray 10 is lifted down after termination of printing; and a control unit 70 which stops descending of the sheet feeding tray 10 at the second position (no-sheet erroneous detection prevention stop position H) in front of the position where it is predicted that the sheet presence detection sensor 58 detects no sheet on the basis of the past position information (T1-T6) of the first position stored in the storage unit 71.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus, a paper feed tray stop position setting method, and a program.

  In a stencil printing apparatus (image forming apparatus), an image is printed (formed) on a sheet by a printing drum (plate cylinder) around which a master that has been subjected to platemaking is wound. Specifically, a sheet as a sheet-like storage medium sent at a predetermined timing from a sheet feeding device to a printing drum (plate cylinder) wound with a master that has been subjected to plate making is a pressing means such as a press roller or an impression cylinder. Pressed with. Then, the ink supplied from the inside of the printing drum oozes out from the stencil portion of the master due to the pressing action at this time and is transferred onto the paper, and a printed image is formed on the paper.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, a toner image formed on a photosensitive drum or a photosensitive belt as an image carrier is transferred to a sheet sent from a paper feeding device at a predetermined timing. An image is formed by transfer by means.

  In a paper feeding apparatus that is connected to or built in an image forming apparatus such as a printing apparatus, a copying apparatus, or a printer as described above, a paper-out detecting unit that detects the absence of paper in the paper feeding tray is used. It has been. As this paper absence detection means, there is a method of detecting the presence or absence of paper with a reflective sensor installed in the paper feed tray, and when the paper loaded on the bottom plate of the paper feed tray runs out and the bottom plate is lowered, the filler Have a method of detecting by blocking the photo interrupter.

As a means to prevent misdetection of paper for this paper presence / absence detection,
-Paper presence detection is performed only when the paper feed tray is at the paper feed position (upper limit position).

-From the start of paper feeding until the next paper can be fed, the paper presence / absence detection result is ignored.
It has already been known that a method for detecting the presence or absence of paper at the next paper feed start timing has been proposed. As an example of the latter, there is a technique disclosed in, for example, Japanese Patent Laid-Open No. 2000-327177. This technology includes a paper feed unit that feeds paper stored in a paper storage unit, a paper out detection unit that detects the absence of paper in the paper storage unit, and a paper supply unit according to a detection result of the paper out detection unit. An image forming apparatus for forming an image on a sheet fed from a sheet storage unit, wherein the control unit performs the following operation after the sheet feeding start by the sheet feeding unit. The detection result of the out-of-paper detection means is invalidated until the paper can be fed.

  However, in the conventional paper misdetection prevention means including the above-mentioned known examples, when the paper feed tray is lowered after the printing is finished, the paper edge may be sandwiched between the paper feed rollers, or the lowering may occur. In some cases, the edge of the sheet hits the side of the printing apparatus and the edge of the sheet is raised. In such a state, there is no paper on the paper presence / absence sensor in the paper feed tray, and “no paper” is erroneously detected.

  In such a case, the presence / absence of the sheet is not detected until the next printing is started. If the actual sheet remains, the sheet is detected at the time of the next printing, so that it is possible to prevent erroneous detection that there is no sheet. However, if the sheet is really out of paper, the operator starts printing without noticing that there is no paper, and detects “no paper” at the timing when the paper feeder starts feeding. The operator has to perform a paper replenishment operation after detecting the absence of the paper, and there is a problem that the operation is delayed.

  Therefore, a problem to be solved by the present invention is to prevent erroneous detection of paper out due to paper rising or the like, and to improve the efficiency of printing work.

  In order to solve the above problems, one aspect of the present invention provides a paper feeding unit that feeds paper from a paper feeding tray to the image forming unit, a paper presence / absence detecting unit that detects the presence / absence of paper on the paper feeding tray, And an elevating unit for elevating and lowering the paper feed tray. When the paper feed tray is lowered after the image formation is completed, the past paper detection of the absence of paper while the paper feed tray is being lowered. Based on the position information stored in the storage means and the storage means for storing the information on the position of the paper feed tray, the paper supply at a position before the position where the paper presence / absence detection means is predicted to detect the absence of paper. And a control means for stopping the lowering of the tray.

  According to one embodiment of the present invention, it is possible to prevent erroneous detection of the absence of a sheet due to a sheet rising, and to improve the efficiency of printing work. Problems, configurations, and effects other than those described above will be clarified in the following description of embodiments.

1 is a schematic configuration diagram showing an overall configuration of a stencil printing machine as an image forming apparatus. It is the schematic which shows the structure of the paper feed tray raising / lowering part of the stencil printing machine in FIG. It is a block diagram which shows the control structure of the stencil printing machine in FIG. FIG. 10 is an explanatory diagram showing a flow of an operation for determining a descent stop position for preventing erroneous detection of no paper when the paper feed tray is lowered. 6 is a flowchart illustrating a processing procedure of a paper feed tray lowering process after printing is completed. FIG. 10 is an explanatory diagram illustrating a memory configuration of a storage unit when a paper feed tray lowering time when it is detected that there is no paper is stored for each paper type. It is explanatory drawing which shows a process when taking out data from a memory | storage part according to the setting of a paper type, and determining a stop position. It is a figure which shows the example of a display of a paper presence / absence false detection prevention stop setting screen. It is a figure which shows the example of a display of a no paper misdetection prevention stop position setting screen. It is a figure which shows the state when detecting the paper absence in a prior art.

  When the paper feed tray is lowered after printing is completed, especially when the number of remaining sheets is small, the end face of the paper hits the side of the printing device, and the end face of the paper rises, which may cause a false detection of "no paper". It is as described above. Therefore, the present invention stores the timing for detecting “no paper” during the descent, and sets the stop timing immediately before the position where it is predicted that the “paper out” is erroneously detected based on the stored information. It is characterized by. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an overall configuration of a stencil printing machine 1 as an image forming apparatus, and FIG. 2 is a schematic diagram showing a configuration of a paper feed tray lifting / lowering unit. First, the outline | summary of the stencil printing machine 1 is demonstrated using FIG. 1, FIG.

  In FIG. 1, a stencil printing machine 1 basically includes a scanner unit 2, a plate making unit 3, a plate discharging unit 4, a paper feeding unit 5, a printing unit 6, and a paper discharge unit 7.

  The scanner unit 2 is a part that reads a set original as image information. The plate making unit 3 is a portion that writes image information read by the scanner unit 2 on a plate (hereinafter referred to as a master) M, conveys the master M to the drum 8 of the printing unit 6, and winds the master M around the outer periphery of the drum 8.

  The plate making unit 3 is unitized, and is guided by a rail (not shown) so that the plate making unit 3 can be pulled out to the outside of the device main body 1a, which is the main body of the stencil printing machine 1, in this example, the right lateral direction (arrow a direction). Has been. This drawing is performed when replacement replenishment when the master M runs out or when jam processing is performed in the plate making unit 3. The plate making unit 3 is pulled out of the apparatus main body 1a, and the master M is exchanged or jammed from the upper part. The plate removal unit 4 is a portion that peels off the master M wound around the circumference of the drum 8 that is no longer necessary after the printing is finished, and stocks the discharged master M.

  The paper feeding unit 5 is a part that separates the set paper P into one sheet and conveys it to the printing unit 6. A paper feed tray (hereinafter referred to as a paper feed tray) 10 on which a pair of side fences 50 for guiding the paper P is arranged is loaded with the paper P thereon and supported by the stencil printing machine 1 so as to be movable up and down. Has been. The stacking height of the paper P is detected by a paper upper limit detection sensor, and based on this detection information, the paper feed tray 10 is moved by the lifting mechanism 100 schematically shown in FIG. 2 so that the position of the uppermost surface of the paper P is constant. Is moved up and down while keeping the paper stacking surface horizontal.

  Here, the lifting mechanism 100 of the paper feed tray 10 will be described with reference to FIG. Guide grooves 61a and 61b are respectively provided in the front and rear side plates 101a and 101b integrated with the apparatus main body 1a, and the pair of rack plates 51 and 52 are configured to move up and down slidably along the guide grooves 61a and 61b. Here, guide pins are arranged toward the outside of the front and rear side plates from the respective rack plates 51 and 52 arranged inside the front and rear side plates 101a and 101b, and the guide pins are inserted from the outside of the front and rear side plates 101a and 101b. A guide member to be sandwiched is disposed. Thereby, the pair of rack plates 51 and 52 can slide along the guide grooves 61a and 61b.

  A paper feed table motor 56 that drives the paper feed tray 10 up and down is attached to a side plate of the apparatus main body 1a. A gear 57 attached to the rotation shaft of the sheet feed table motor 56 is supported by front and rear side plates 101a and 101b by bearings (not shown). The gear 57 meshes with one of the lift gears 55 (front side plate 101a side) fixed to both shaft end sides of the lift drive shaft 54 that is rotatably arranged. When the paper feed table motor 56 rotates, the lift gear 55 Rotate.

  Further, the elevating gear 55 is engaged with the racks of the respective rack plates 51 and 52 disposed inside the front and rear side plates 101a and 101b, and the rack plates 51 and 52 are simultaneously driven to move up and down by the rotation of the paper feed table motor 56. Will be. The paper feed tray 10 is attached to the rack plates 51 and 52, and the paper feed tray 10 is raised and lowered simultaneously with the raising and lowering of the rack plates 51 and 52.

  Note that springs 53 are attached to the rack plates 51 and 52 for assisting when moving up and down. 2, only the spring 53 attached to the rack plate 51 is shown. A sheet presence / absence detection sensor 58 is disposed on the sheet feed tray 10, and a lower limit sensor 60 is disposed on the side plate 101 b for detecting the lower limit of the sheet feed tray 10. The lower limit sensor 60 is used for control such as detecting an actuator (not shown) provided on the rack plate 52 to detect the lower limit position of the paper feed tray 10 and stopping the paper feed motor 56.

  In FIG. 1, a paper feed roller 11a and a separation roller 11b are provided so as to abut on the uppermost paper P. The sheet feeding roller 11a and the separation roller 11b are rotationally driven by a rotational driving means, for example, a driving force from a main motor is controlled by an electromagnetic clutch, or by a rotational driving means such as an independent drive by a stepping motor or the like.

  Since the separation roller drive shaft 27 connected to the rotation driving means is connected to the paper supply roller shaft 28 by the belt 26 (or gear), the rotation of the separation roller drive shaft 27 causes the paper supply roller shaft 28 to rotate. To do. As a result, the separation roller 11b provided with the one-way clutch and the paper feed roller 11a rotate at the same time. Here, the sheet feeding roller shaft 28 is rotatably supported by the sheet feeding arm 29, and the sheet feeding roller 11 a can be rotated together with the sheet feeding arm 29.

  The upper limit detection of the paper P loaded on the paper feed tray 10 generally uses either a detection mechanism that detects the height of the leading edge of the paper or a detection mechanism that detects the height of the paper supply roller 11a. Is. In this embodiment, since the paper front end height detection mechanism is used, the paper front end height detection mechanism will be described.

  In the paper tip height detection mechanism, the paper upper limit detection filler 31 is rotatably fixed to a bracket fixed to the paper feed stay 40 by a stepped screw. In addition, a roller 31a is rotatably disposed at a paper contact portion of the paper upper limit detection filler 31. The roller 31a is fixed to a shaft crimped by the paper upper limit detection filler 31 so as to be rotatable by an E-type retaining ring or the like.

  When the paper feed tray 10 is raised, the roller 31a comes into contact with the front end portion of the paper. The reverse end portion of the paper upper limit detection filler 31 is detected by a paper upper limit detection sensor 41 disposed in the paper feed stay 40. Here, the filler is used as the detection mechanism. However, the filler is merely an example, and another method using a reflective sensor or the like may be employed.

  The sheet feeding arm 29 of the sheet feeding pressure adjusting mechanism can be rotated about the separation roller driving shaft 27 as a fulcrum, and the sheet feeding roller 11 a can be rotated together with the sheet feeding arm 29. Further, a spring is disposed at the end of the paper feeding arm 29 in a direction to push down the paper feeding roller 11a, and the pressing force of the paper feeding roller 11a against the paper P is changed by changing the spring length by an adjusting mechanism (not shown). can do.

  The separation pad 12 of the separation pressure adjusting mechanism for separating one sheet is in contact with the separation roller 11b by a guide (not shown), and the separation pad 12 is pressed against the separation roller 11b by the pressure of the pressure spring 18. This creates a separation pressure.

  A pair of registration rollers 13 is arranged on the downstream side, which is the extension of the separation roller 11b in the paper conveyance direction, in this example, the left lateral direction opposite to the arrow a. The registration roller pair 13 grips the leading end of the conveyed paper P, and conveys it between the outer peripheral surface of the drum 8 and a press roller 9 described later in time.

  The upper guide plate 14 and the lower guide plate 15 are fixed to the side plates of the apparatus main body 1a and guide the paper P to be fed. Further, a paper leading edge detection sensor 20 is arranged in front of the registration roller pair 13 in the transport direction, that is, upstream in the transport direction, detects the leading edge position of the fed paper P, and controls the subsequent feed amount to register the paper. The amount of deflection of the paper at the 13 pairs of rollers is made constant. The sheet deflection at the registration roller pair 13 part has an important function of correcting the contact state and skew of the sheet tip against the registration roller pair 13 part, and keeping the deflection amount optimal is an important matter for preventing image misalignment. It is a well-known fact.

  The paper feed unit 5 includes a lifting mechanism 100, a paper feed separation unit 11, a registration roller pair 13, and the like. The elevating mechanism 100 includes a paper feed tray 10 on which the paper P is loaded and a paper feed motor 56 for raising and lowering the paper feed tray 10, a gear 57, a lift gear 55, rack plates 51 and 52, a spring 53, a rack 102, and a guide groove 61a. 61b. The paper feed separation unit 11 includes a separation roller 11 b that separates the paper P stacked on the paper feed tray 10 into one sheet, a separation pad 12, and the like. The registration roller pair 13 transports the paper P separated by the paper feed separation unit 11 to the printing unit 6 in timing with the leading edge of the image of the master M.

  The printing unit 6 includes a drum 8 and a press roller 9, and presses the conveyed paper P against the drum 8 by the press roller 9, thereby transferring an image of the master M wound around the drum 8 onto the paper P. .

  The paper discharge unit 7 peels off the printed paper P from the drum 8 and sucks the paper P on the conveyance belt surface when the paper P is discharged. The paper discharge unit 7 stocks the printed paper P. 17. The suction unit 16 includes a conveyance belt, a drive source (not shown), a fan for sucking the paper P to the belt, and the like, and a paper discharge detection sensor 21 for detecting the paper P is disposed on the paper conveyance surface. ing. In general, the paper leading edge detection sensor 20 and the paper discharge detection sensor 21 are sensors of a reflection type, a transmission type, or a filler type.

  FIG. 10 is a diagram showing a state when the absence of paper in the related art described in the problem is detected. When the paper feed tray 10 is lowered after the printing is finished, the leading edge of the paper P may be sandwiched between the paper feeding rollers 11a. The tip of the arm may be raised. This phenomenon is likely to occur when the number of remaining sheets on the sheet feeding tray 10 is small. In this state, the sheet P runs out on the upper side of the sheet presence / absence detection sensor 58, and the sheet presence / absence detection sensor 58 cannot detect the sheet P and detects “no sheet”.

  The reason why the paper feed tray 10 is lowered at the end of printing is to facilitate the paper replenishment work, and when the paper P and the paper feed roller 11a are kept in contact, the paper P adheres to the paper feed roller 11a. This is to prevent this. In addition, the paper-out erroneous detection while the paper feed tray is lowered is particularly likely to occur when the remaining number of sheets P is small.

  FIG. 3 is a block diagram showing a control configuration of the stencil printing machine 1 according to the present embodiment. The control configuration is configured around the control unit 70. That is, the printing unit 6, the plate making unit 3, the paper feeding unit 5, the paper discharge unit 7, the ADF image reading unit 2 a, the fixed base image reading unit 2 b, the storage unit 71, the plate discharging unit 4, and the operation panel 72 are respectively connected to the control unit 70. Are connected so that signals can be sent and received. The control unit 70 receives information necessary for control from each connected unit as a signal, and outputs a control signal to each unit to control each unit. Thereby, each part can perform the operation | movement which cooperated mutually. That is, the control unit 70 can transmit and receive a detection signal or a control signal to and from each connected unit, and can control each unit independently or in cooperation.

  The control unit 70 includes modules of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disc Drive) memory (not shown). The CPU processes the data according to the procedure of the program stored in the ROM. The RAM is used as a work memory and a buffer when the CPU processes. The HDD is a large-capacity storage medium that holds a large amount of data in a readable / writable manner.

  The printing unit 6 performs stencil printing. The plate making unit 3 creates a plate for performing stencil printing. The paper feeding unit 5 feeds the paper P to the printing unit 6 side. The paper discharge unit 7 discharges the printed paper P outside the printing apparatus. The ADF image reading unit 2a reads the image information on the document while sending the document, and transmits it to the control unit 70 side. The fixed base image reading unit 2b reads the image information on the document while the document is fixed, and transmits it to the control unit 70 side. The ADF image reading unit 2 a and the fixed base image reading unit 2 b correspond to the scanner unit 2.

  The storage unit 71 retains data such as time and / or distance from the start of lowering as information at which “paper out” is detected in the middle of lowering of the paper feed tray 10 in the past, and information necessary for printing Holding. The plate discharging unit 4 discharges the plate (master M) used for printing out of the stencil printing machine 1.

  Further, the control unit 70 determines a stop timing immediately before it is predicted that the “paper out” is erroneously detected from the history data of the timing at which “paper out” is detected during the lowering of the paper feed tray 10, and the paper feeding unit 5, the lowering of the paper feed tray 10 is stopped at that timing. The history data is held in the storage unit 71. The operation panel 72 is a man-machine interface with the user, can select whether or not to perform each control, and can input information necessary for printing. For example, in this embodiment, in order to prevent erroneous detection of the absence of paper while the paper feed tray 10 is being lowered, the paper feed tray 10 is not stopped during the lowering. In order to do this, it is possible to select whether or not to perform stop control of the paper feed tray 10 from the operation panel 72. Further, the stop timing of the paper feed tray 10 can be selected and determined from an average value, an upper limit value, and a lower limit value from the past erroneous detection timing of no paper.

  FIG. 4 is an explanatory diagram showing a flow of operations for determining a descent stop position for preventing erroneous detection of no paper when the paper feed tray is lowered.

The first paper-free case (denoted as paper-free case 1 in the figure) shows a state in which the paper feed tray 10 has detected no paper at the first distance h1 from the paper feed roller 11a. Further, the second paper absence case (denoted as paper no case 2 in the figure) shows a state in which no paper is detected at the second distance h2 from the paper feed roller 11a of the paper feed tray 10. The data of the first and second distances h1 and h2 are stored in the storage device 71m of the storage unit 71, and the control unit 70 determines from the stored data the stop position of the paper feed tray 10 (the no-paper false detection prevention stop position). H) is determined, and the paper feed tray 10 is stopped at that position. When “average” is selected at the time of determining the stop position, the average of the first and second distances h1 and h2, that is, the no-paper false detection prevention stop position H, as shown in FIG.
H = (h1 + h2) / 2
Determine from the formula.

  FIG. 4 shows that the distance or height at which no paper detection is detected changes even if the type and size of the paper P are the same. The detected height of no sheet varies depending on the contact state of the leading end of the sheet P with the wall surface of the stencil printing machine 1, the manner in which the sheet P is placed on the sheet feeding tray 10, the position, and the like.

  FIG. 5 is a flowchart showing the processing procedure of the paper feed tray lowering process after the printing is completed. This processing procedure is executed by the CPU of the control unit 70.

  When the paper feed tray is lowered after the printing is finished and the stop position of the paper feed tray is determined, first, it is checked whether or not the stop setting for preventing the presence / absence of paper detection is set (step 1: step S). Abbreviated). If it is possible to set a stop position for preventing erroneous detection of paper presence by this check and the history data accumulation amount (S2) for detection of paper absence is sufficient, a paper presence / absence erroneous detection prevention position is set at the stop position of the paper feed tray 10. Is set (S3). Further, when the stop position setting (S1) for preventing erroneous detection of paper presence / absence is negative, or when the history data accumulation amount for detecting the absence of paper at S2 is insufficient, a preset stop position (predetermined stop position) Is set (S4).

  It is determined that the accumulated amount of history data for detecting the absence of paper in S2 is sufficient when there is a certain number of history data, and is insufficient when the number is not sufficient. Note that the fixed number of times is, for example, the number of times obtained experimentally is set as an initial value, and if the number of times increases, the average is increased accordingly, so the accuracy increases. In addition, if the user feels that the number of times is insufficient during use, the initial value of the number of times history data is accumulated can be set and input from the operation panel 72.

  The predetermined stop position is an initial value set in advance, and can be set by a descent distance or a descent time. It is also possible to set a lower limit position for lowering.

  When the stop position is set in S3 or S4, the paper feed tray 10 starts to descend (S5). The presence or absence of paper is detected during the descent (S6). If the sheet presence / absence detection sensor 58 detects that there is no sheet in the middle of descending, the stop position is reset to a predetermined stop position (lower limit position or the like) (S8). Then, the descent time or the descent distance from the start of the descent of the paper feed tray 10 until the absence of paper is detected is stored in the storage device 71m of the storage unit 71 (S9). After the storage in S9 ends, or when the paper feed tray 10 reaches the stop position with the paper presence / absence detection sensor 58 detecting the presence of paper (S7: YES), the paper feed tray 10 is stopped (S10). The descent process is terminated.

  FIG. 6 is an explanatory diagram showing a memory configuration of the storage unit 71 when the paper tray lowering time when it is detected that there is no paper is stored for each paper type.

  In the present embodiment, the memory area of the storage unit 71 is prepared in advance for each paper type, and the descent time from when the paper feed tray 10 starts to descend until the absence of paper is detected is stored in the storage unit 71. At that time, the memory area to be stored is changed according to the paper type setting. In FIG. 6, three storage units, a plain paper information storage unit 71a, a thick paper information storage unit 71b, and a thin paper information storage unit 71c, are set, and data for each time is stored in the areas T1, T2, T3,. The Also, when determining the stop position H for detecting no-paper error detection set in S3, data is extracted from the storage unit 71 according to the setting of the sheet type, and the stop position is determined.

  FIG. 7 is an explanatory diagram showing processing when data is extracted from the storage unit 71 and the stop position is determined according to the paper type setting.

As shown in FIG. 7, the paper presence / absence detection sensor 58 is in the state of the paper tray 10 being lowered while the plain paper data is stored in the areas T1 to T5 of the plain paper information storage unit 71a. When the absence is detected, the descent time t at that time is stored in the region T6. When determining the stop position H when the sheet feeding tray 10 is lowered next time, the stop position is determined from the set determination method and stored history data according to the following cases.
1. When the determination method is “average” The feed tray 10 is stopped by setting the average value of the values (distance or time) stored from the region T1 to the region T6 as the descent time until stopping.
2. When the determination method is “upper limit” The shortest time (time when the descending amount is small) stored from the region T1 to the region T6 is set as the descending time, and the paper feed tray 10 is stopped.
3. When the determination method is “lower limit”: The longest time (time when the amount of descending is large) stored from the region T1 to the region T6 is set as the descending time, and the paper feed tray 10 is stopped.

  FIG. 8 is a diagram illustrating a display example of a paper presence / absence erroneous detection prevention stop setting screen. In this screen, a selection screen of “do not stop” or “stop” is displayed as a “paper presence / absence erroneous detection prevention stop setting” screen 72 a on the operation panel 72. When “not stop” is selected, the paper feed tray 10 descends without stopping to a position set in advance as the paper misdetection prevention stop position H. When “Stop” is selected, the paper feed tray 10 stops at the no-paper false detection prevention stop position H.

  FIG. 9 is a diagram illustrating a display example of a no-paper error detection prevention stop position setting screen. In this screen, a selection screen of “average”, “upper limit”, and “lower limit” is displayed on the operation panel 72 as a “paper misdetection prevention stop position” screen 72b. When “Average” is selected, the stopping method 1 is executed. When the “upper limit” is selected, the second stopping method is executed. When the “lower limit” is selected, the above-described stopping method 3 is executed.

  In this way, the “non-stop” and “stop” selection screens are displayed on the “paper presence / absence detection prevention stop setting” screen 72a to allow the user to select. In addition, a selection screen of “average”, “upper limit”, and “lower limit” is displayed on the “paper out misdetection prevention stop position” screen 72b to allow the user to select. With this selection, it is possible to set the stop position when the paper feed tray 10 is lowered, which is convenient for the user.

  Further, when the paper feed tray 10 is lowered, the paper presence / absence detection sensor 58 erroneously detects “no paper” due to the rise of the paper P or the like, not immediately after the paper feed tray 10 is lowered. In the process, the amount of rising increases, and after a short time has passed after the descent, “no paper” is erroneously detected. Therefore, the stop timing when the paper feed tray is lowered is set to a timing to stop before the position where it is predicted that “no paper” is erroneously detected. As a result, it can be seen that erroneous detection of “no paper” can be prevented.

  As described above, if the present invention is adapted to the present embodiment, the following effects can be obtained. In the following description, each component in the claims corresponds to each part of the present embodiment, and when the terms are different, the latter is shown in parentheses, and a corresponding reference symbol is attached. The relationship between the two was clarified.

  1) Paper supply means (paper supply roller 11a) for supplying paper P from the paper supply tray 10 to the image forming means (printing unit 6) side, and paper presence / absence detection means for detecting the presence / absence of paper on the paper supply tray 10 An image forming apparatus (stencil printing machine 1) having a (sheet presence / absence detecting sensor 58) and an elevating means (elevating mechanism 100) for elevating and lowering the paper feed tray 10, and after the completion of image formation (printing), Storage means for storing positional information (time t) of the position of the paper feed tray 10 when the paper presence / absence detection means (paper presence / absence detection sensor 58) detects the absence of paper when the paper feed tray 10 is lowered. (Storage unit 71) and the sheet presence / absence detection unit (sheet presence / absence detection sensor 58) based on the past position information (for example, T1 to T6) stored in the storage unit (storage unit 71). When it detects no paper According to the present embodiment, there is provided control means (control unit 70) for stopping the lowering of the paper feed tray 10 at a second position (position where there is no paper misdetection prevention position H) before the measured position. Since the paper feed tray 10 is stopped at a position where the paper P does not rise (paper no false detection prevention stop position H), it is possible to prevent the paper no misdetection due to the paper P rising. As a result, the efficiency of printing work can be improved.

  2) The control means (the control unit 70) determines the second position (the no-paper false detection prevention stop position H) when the accumulated amount of history data of the position information (T1 to T6) is equal to or greater than a preset number of times. According to the present embodiment in which the lowering of the paper feed tray 10 is stopped, the paper misdetection prevention stop position is detected only when the paper no misdetection stop position H without reliably performing the paper misdetection can be specified. Since the operation is stopped at H, it is possible to prevent erroneous detection of the absence of the sheet due to the rising of the sheet P or the like.

  3) According to the present embodiment, the second position (paper missing false detection prevention stop position H) is set based on the average value of the accumulated position information (T1 to T6) of the first position. As long as the first position is not greatly deviated from the average value, it is possible to prevent erroneous detection of the absence of the sheet due to the sheet P being raised.

  4) According to the present embodiment, the second position (paper missing error detection prevention stop position H) is set based on the accumulated upper limit value of the position information (T1 to T6) of the first position. If the first position is smaller than the upper limit value, it is possible to prevent erroneous detection of the absence of paper due to the rising of the paper P or the like.

  5) According to the present embodiment, the second position (paper missing erroneous detection prevention stop position H) is set based on the lower limit value of the accumulated position information (T1 to T6) of the first position. If the first position is larger than the lower limit value, it is possible to prevent erroneous detection of the absence of paper due to the paper P being raised.

  6) According to the present embodiment provided with setting means (operation panel 72: paper presence / absence erroneous detection prevention stop setting screen 72a) for setting validity / invalidity of the control of the control means (control unit 70), the use state of the user Accordingly, it is possible to set each time the user uses, and convenience is improved.

  7) Whether the control means (the control unit 70) determines the front position (paper missing false detection prevention stop position H) based on an average value, an upper limit value, or a lower limit value of past paper absence detection positions. According to the present embodiment provided with the selection means (operation panel 72: paper-out misdetection prevention stop position selection screen 72b), the amount of lowering of the paper feed tray 10 and the ratio of preventing misdetection of paper out at the user's will Can be adjusted.

  8) According to the present embodiment in which the storage means (storage unit 71) stores the position information of the first position for each paper type, the no-paper false detection prevention stop position H is accurately set for each paper type. can do.

  9) Paper supply means (paper supply roller 11a) for supplying paper P from the paper supply tray 10 to the image forming means (printing unit 6) side, and paper presence / absence detection means for detecting the presence / absence of paper on the paper supply tray 10 This is a method for setting the stop position of the paper feed tray 10 of the image forming apparatus (stencil printing machine 1) having (paper presence / absence detection sensor 58) and lifting means (lifting mechanism 100) for raising and lowering the paper feed tray 10. After the image formation (printing) is completed, when the paper feed tray 10 is lowered, the position of the paper feed tray 10 when the paper presence / absence detection means (paper presence / absence detection sensor 58) detects the absence of paper is detected. A step (S9) of storing the position information (time t) in the storage means (storage unit 71), and the position information (for example, T1 to T6) of the past first position stored in the storage unit (storage unit 71). ) Based on the presence of the paper The lowering of the paper feed tray 10 is stopped at a second position (a paper no false detection prevention stop position H) before the position where the stage (paper presence / absence detection sensor 58) is predicted to detect no paper (S7, S10). In this embodiment, the paper feed tray 10 is stopped at a position where the paper P does not rise (paper no false detection prevention stop position H). No false detection can be prevented, and the efficiency of printing work can be improved.

  10) In the process of lowering the paper feed tray 10 containing the paper P fed to the image forming means (printing unit 6) to the computer (control unit 70, CPU) after completion of the image formation, the paper feed tray 10 The positional information (for example, T1 to T6) of the first position of the paper feed tray 10 when the paper presence / absence detection means (paper presence / absence detection sensor 58) for detecting the presence or absence of the paper P detects the absence of paper. Based on the procedure (S9) stored in the storage unit (storage unit 71) and the past position information (for example, T1 to T6) stored in the storage unit (storage unit 71), the presence / absence of the sheet A procedure for stopping the lowering of the paper feed tray 10 at a second position (paper missing error detection stop position H) before the position where the detection means (paper presence / absence detection sensor 58) is predicted to detect the absence of paper (S7). , S10) and Is downloaded, the computer (control unit 70, CPU) stops the paper feed tray 10 at a position where the paper P does not slide up (paper no false detection prevention stop position H). Therefore, it is possible to prevent erroneous detection of the absence of the paper due to the paper P rising, and to improve the efficiency of the printing work.

  In the present embodiment, the program is stored in the ROM of the control unit 70, but may be stored in a recording medium. In this case, the program can be installed in the computer (control unit 70, CPU) using this recording medium. The recording medium may be a non-transitory recording medium. The non-transitory storage medium is not particularly limited, and for example, a recording medium such as a CD-ROM can be used.

  In this embodiment, the stencil printing machine 1 is described as an example of an image forming apparatus. However, a paper feeding apparatus that supplies paper to known image forming means such as an electrophotographic system or a liquid jet system. Any image forming apparatus of any image forming system can be applied as long as the image forming apparatus is provided with the above.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention, and all technical matters included in the technical idea described in the claims are included. The subject of the present invention. The above embodiment shows a preferable example, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the contents disclosed in this specification, These are included in the technical scope described in the appended claims.

1 Stencil printing machine (image forming device)
6 Printing section (image forming means)
10 Paper feed tray 11a Paper feed roller (paper feed means)
58 Paper presence / absence detection sensor (paper presence / absence detection means)
70 Control unit (control means)
71 Storage section (storage means)
72 Operation panel (setting means, selection means)
72a Paper detection error detection stop setting screen 72b Paper detection error detection stop position selection screen 100 Lifting mechanism (lifting means)
H No-paper false detection prevention stop position (second position)

JP 2000-327177 A

Claims (10)

Paper feeding means for feeding paper from the paper feeding tray to the image forming means side;
Paper presence / absence detecting means for detecting the presence / absence of paper on the paper feed tray;
Elevating means for elevating and lowering the paper feed tray;
An image forming apparatus having
Storage means for storing position information of the first position of the paper feed tray when the paper feed tray is lowered after the image formation is completed,
Based on the past position information of the first position stored in the storage means, the lowering of the paper feed tray is stopped at the second position before the position where the paper presence / absence detection means is predicted to detect the absence of paper. Control means for causing
An image forming apparatus. The image forming apparatus according to claim 1,
The image forming apparatus that stops the lowering of the sheet feeding tray at the second position when the accumulated amount of the history data of the position information is equal to or more than a preset number of times. The image forming apparatus according to claim 1, wherein:
The image forming apparatus in which the second position is set based on an average value of the accumulated position information of the first position. The image forming apparatus according to claim 1, wherein:
The image forming apparatus in which the second position is set based on an upper limit value of the accumulated position information of the first position. The image forming apparatus according to claim 1, wherein:
The image forming apparatus in which the second position is set based on a lower limit value of the accumulated position information of the first position. The image forming apparatus according to claim 1, wherein:
An image forming apparatus comprising setting means for setting validity / invalidity of control of the control means. The image forming apparatus according to claim 1, wherein:
An image forming apparatus comprising: a selecting unit that selects whether the control unit sets the second position based on an average value, an upper limit value, or a lower limit value of the first position. The image forming apparatus according to any one of claims 1 to 7,
An image forming apparatus in which the storage unit stores position information of the first position for each sheet type. Paper feeding means for feeding paper from the paper feeding tray to the image forming means side;
Paper presence / absence detecting means for detecting the presence / absence of paper on the paper feed tray;
Elevating means for elevating and lowering the paper feed tray;
A paper feed tray stop position setting method for an image forming apparatus having
Storing the position information of the first position of the paper feed tray in the storage means when the paper feed tray is lowered after the image formation is finished,
Based on the past position information of the first position stored in the storage means, the lowering of the paper feed tray is stopped at the second position before the position where the paper presence / absence detection means is predicted to detect the absence of paper. A process of
Feed tray stop position setting method equipped with. On the computer,
When the paper presence / absence detecting means for detecting the presence / absence of the paper on the paper feed tray detects the absence of paper in the process of lowering the paper feed tray containing the paper to be fed to the image forming means side after the end of image formation Storing the position information of the first position of the paper feed tray in the storage means;
Based on the past position information of the first position stored in the storage means, the lowering of the paper feed tray is stopped at the second position before the position where the paper presence / absence detection means is predicted to detect the absence of paper. And the procedure
A program for running