JP2007137653A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of detecting the presence or absence of a paper sheet in the shortest time irrespective of size and direction of a paper sheet on which image is formed and reducing load of a system by monitoring the presence or absence of paper sheet to the minimum necessary. <P>SOLUTION: This image forming device is provided with a paper feeding means for feeding a transfer paper into an image forming means, a holding means for holding the transfer paper stored in the paper feeding means, a detection means for detecting the presence or absence of transfer paper, and a control means for controlling monitoring of the results of detection. The detection means 63 is installed in the holding means 61 and its installation position moves in accordance with paper size of the transfer paper stored in the paper feeding means. The control means controls monitoring of the results of detection by the detection means for only predetermined time from the start of feeding operation of the transfer paper. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a paper feed mechanism, and more particularly to an image forming apparatus having a function of detecting the presence or absence of paper in a paper feed unit.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a laser printer, a plurality of paper feed ports are formed so that images can be formed on a large number of paper sizes such as A3, B4, A4, B5, or an arbitrary size, and in a vertical and horizontal direction. Are provided so that sheets of various sizes and directions can be stocked continuously in trays and cassettes.

  Recently, as the need for high-speed processing increases, it is increasingly required to increase the conveyance speed in the paper conveyance system. In order to achieve this high-speed printability, when performing continuous printing, in order to be able to discharge many sheets in a short time, the sheets are fed one after another and the intervals between the sheets are kept as narrow as possible. It is starting to print.

  In addition, miniaturization and improvement in productivity of the image forming apparatus are also demanded, and the paper conveyance distance, that is, the distance from the paper feeding position to the transfer position where the image is formed on the paper has been shortened as much as possible. .

  It is desirable that operations such as writing and image formation be started after confirming the presence or absence of paper in the paper feed tray, but in the situation of high speed printing and device miniaturization described above, Before confirming the presence or absence of the next sheet, the next writing image forming operation is often started while transferring the previous sheet. This is because a sensor for detecting the presence / absence of a sheet is disposed in the vicinity of the exit of the sheet feed tray, and the presence / absence of the next sheet cannot be confirmed while the rear end of the previous sheet is in the sheet feed tray. Also related. If it is determined that there is no paper after the start of the writing image forming operation, the image being operated cannot be printed, and the toner required for this operation is wasted, and the photoconductor is consumed due to the unnecessary writing image forming operation. .

For example, in Japanese Patent Application Laid-Open No. 2003-228561, the paper detection unit is positioned in the vicinity of the rear end of the minimum paper size so that the detection of the final paper is accelerated, and the wasteful image formation process is not performed, so that the toner consumption is reduced. And an image forming apparatus capable of suppressing deterioration of the apparatus.
JP 2003-237985 A

  The image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2004-228561 positions the paper detection unit near the rear end of the minimum paper size. For example, when the initial paper size is B5, the paper detection unit is provided near the rear end. . In the continuous printing of B5, it may be possible to detect the presence or absence of paper earlier, but this is not the case when A3 is continuously printed.

  Faster detection of the presence / absence of paper is an essential element not only for quick cancellation processing for preventing waste of toner, consumption members, etc., but also for rapid recovery processing for the next printing operation. It is desirable to be able to determine the presence / absence state in the shortest time, regardless of the paper size and direction.

  Further, from the viewpoint of the control system, the system load is reduced by monitoring only for a predetermined period rather than constantly monitoring the presence or absence of paper.

  Accordingly, in view of the above points, the present invention can detect the presence / absence state of paper in the shortest time regardless of the paper size and direction in which an image is formed, and performs the minimum necessary monitoring on the presence / absence of paper. An object of the present invention is to provide an image forming apparatus capable of reducing the load.

  In order to achieve such an object, the invention described in claim 1 includes an image forming unit, a sheet feeding unit that accommodates transfer sheets, separates the transfer sheets one by one, and supplies the sheet to the image forming unit. A holding unit disposed in the paper unit and configured to hold the transfer paper contained in the paper unit in a uniform direction; a detection unit configured to detect the presence or absence of the transfer paper in the paper feeding unit; and the detection unit And an image forming apparatus including a control unit that performs control to monitor a detection result of the detection unit, wherein the detection unit moves in accordance with a sheet size of the transfer paper stored by the sheet feeding unit, and the control unit Is characterized in that control is performed to monitor the detection result of the detection means for a predetermined time from the start of the supply operation by the paper supply means.

  According to the present invention, the detection unit whose installation position moves according to the paper size of the transfer paper stored in the paper supply unit, and the detection result of the detection unit for a predetermined time from the start of the transfer paper supply operation. It has a control means for performing control to be monitored. By including the detection means, the detection means can be moved to any location according to the paper size of the transfer paper, so that it is also possible to move to the rearmost end in the transport direction in which the presence / absence state of paper can be grasped earliest. . And by providing this control means, since a detection result is monitored only for the minimum predetermined time, without constantly monitoring a detection result, there exists an effect which can reduce the load on a system more.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the installation position of the detection means is moved to the rearmost end in the direction in which the transfer paper is supplied by the paper supply means. It is characterized by.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the holding unit can move the disposed position in accordance with the paper size, and the detection unit includes: It is installed in the holding means.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect of the invention, the detection unit is provided on the holding unit that holds a side of the transfer paper perpendicular to a direction supplied by the paper feeding unit. It is characterized by being installed.

  Further, the invention according to claim 5 is the image forming apparatus according to any one of claims 1 to 4, further comprising a timing unit that counts the predetermined time, and the control unit includes the sheet feeding unit. Control that sets the time measuring means after the supply operation by the means is started and performs time measurement, and stops monitoring the detection result of the detection means when the predetermined time has passed. It is characterized by performing.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the control unit monitors the detection result of the detection unit after the predetermined time has elapsed. When the supply operation by the paper feeding unit is continued after the stop, the control for monitoring the detection result is performed again.

  According to the present invention, it is possible to detect the presence / absence state of paper in the shortest time even when an image is formed in any paper size and direction, and the system load is reduced by monitoring the minimum paper presence / absence state. An image forming apparatus that can be reduced is realized.

  A laser printer according to an embodiment of the present invention will be described with reference to the drawings.

  First, an outline of the configuration of the laser printer of this embodiment will be described. FIG. 1 is a schematic diagram showing a unit configuration of the laser printer of this embodiment.

  The laser printer 1 includes a main unit 100, a paper feeding unit 110, a registration unit 120, a fixing unit 130, a duplex unit 140, a mail box unit 150, and a finisher unit 160.

  The main unit 100 is a unit that performs a series of writing such as writing for image formation, development, and fixing control and basic paper feeding, and includes a paper feeding unit 110, a registration unit 120, and a fixing unit 130. The duplex unit 140 reverses the recording paper by a reversing mechanism (switchback) to perform double-sided printing, and re-feeds the recording paper. The mail box unit 150 includes a plurality of paper discharge ports, and discharges the print result to an arbitrary paper discharge port. In this embodiment, 3 bins are provided. The finisher unit 160 performs post-processing such as stack processing and stapling processing that are shifted and sorted for each job printing.

  Next, the paper conveyance path and the like of the laser printer of this embodiment will be described. FIG. 2 is an explanatory diagram showing the sheet conveyance path and the arrangement relationship of each mechanism in the laser printer of this embodiment. In the figure, S is a sensor for detecting the conveyance timing of the recording paper in the paper feeding conveyance path, the reverse conveyance path, etc., P is a solenoid for switching the switching claw for switching the conveyance path, R is paper feeding, The rollers for carrying and discharging are shown.

  That is, R1 is a first paper feed roller, R2 is a second paper feed roller, R3 is a registration roller, R4 is a photosensitive unit (OPC) and transfer roller, R5 is a fixing roller, R6 is a paper discharge to the relay and finisher side Branch left discharge roller R7, branching abandon roller for discharging to the mailbox side, R8 relay relay roller, R9 relay discharge roller, R10 finisher inlet roller, R11 finisher exit roller, R12 double-sided Branch right discharge roller for discharging to the unit side, R13 is a double-sided reversing upper roller, R14 is a double-sided reversing roller, R15 is a double-sided reversing lower roller, R16 is a double-sided transport roller, R17 is a double-sided paper feed roller, R18 is a mailbox The transport roller, R19 is a mailbox 1-bin discharge roller, R20 is a mailbox 2-bin discharge roller, and R21 is a mailbox. Box 3, which is a bottle discharge roller. R15 is not shown.

  Also, S1 is a registration sensor, S2 is a fixing outlet sensor, S3 is a branch sensor, S4 is a relay sensor, S5 is a double-sided inlet sensor, S6 is a double-sided outlet sensor, S8 is a finisher inlet sensor, S9 is a paper discharge port 4 sensor, S10 Is a finisher paper presence sensor, S11 is a finisher full sensor, S12 is a mail box transport sensor, S13 is a mail box 1 bin paper presence sensor, S14 is a mac box 2 bin paper presence sensor, S15 is a mail box 3 bin paper presence sensor, S16 Is a full box 1 bin sensor, S17 is a full 2 box bin sensor, and S18 is a full 3 bin sensor. Although not shown, the discharge port 5 is provided with S7 as a discharge port 5 sensor, S19 as a discharge port 5 paper presence sensor, and S20 as a full discharge sensor.

  P1 is a branch switching sonolide (1), P2 is a branch switching sonolide (2), P3 is a double-sided reversal switching sonolide, P4 is a mailbox discharge switching sonolide (1), and P5 is a mailbox discharge switching sonoride (2). It is.

  Details will be described below. The sheets stored in the sheet feed tray are conveyed one by one by the first sheet feed roller R1 or the second sheet feed roller R2, and when the sheet reaches the registration sensor S1, the rotation of the registration roller R3 is stopped. The conveyance is temporarily stopped.

  The following processing is performed while the paper is stopped. In other words, laser light is irradiated from the optical scanning device of the optical system unit (* portion in the figure), and a potential difference is generated between the irradiated portion and the non-irradiated portion of the photoconductor (R4 left side in the drawing). Then, the toner on the developing roller on which the toner is evenly adhered by the developing unit is placed on the photoconductor to perform development.

  On the other hand, the timing of transferring the toner image written on the photoreceptor by the transfer unit R4 is measured for the paper stopped by the registration sensor, and the registration roller R3 is rotated to resume the conveyance of the paper. As the sheet passes through the transfer unit, the toner image is transferred to the sheet. When the transfer is completed, the toner remaining in the transfer process is removed from the photoconductor by a cleaning unit (not shown). The transferred sheet is conveyed to the fixing roller R5, and the toner is fixed by heat and pressure. Thereafter, the sheet is conveyed to any one of the sheet discharge trays and discharged at a predetermined sonolide and sensor timing. Further, duplex printing can be performed by discharging the paper discharge destination of the fixed paper to the duplex unit and feeding it reversely.

  The sensor S2 detects the completion of the passage of the sheet after the fixing process, and starts preparation for fixing the next sheet. The sensor S5 detects that the trailing edge of the sheet has arrived, and starts the reverse switching process.

  The sonorade is a portion for switching the sheet transport destination. For example, when the sonolide P1 is turned off, the sheet is transported in the relay unit direction (finisher direction). Further, by turning on the sonolide P1 and turning off the sonolide P2, the paper is conveyed in the mail box direction. Further, by turning on both of the sonolides P1 and P2, the sheet is conveyed in the direction of the duplex unit.

  As for the sono-red P3, when the sheet is conveyed from the main body side to the duplex unit, P3 is turned off. Conversely, when the trailing edge of the paper reaches the “reverse direction” arrow in the figure and the paper is reversed, P3 is turned on.

  When the sono-rad P4 is turned on, the paper is conveyed toward the paper discharge port 1. Also, when the sono-rad P4 is turned off and the sono-rad P5 is turned on, the paper is conveyed toward the paper discharge port 2, and when both P4 and P5 are turned off, the paper is conveyed toward the paper discharge port 3. .

  Next, the control system of the laser printer of this embodiment will be described. FIG. 3 is a block diagram showing the configuration of the control system of the laser printer of this embodiment.

  The printer 1 mainly includes a controller unit 310 that performs interface control with the host machine 350 and image data editing control, and an engine unit 330 that performs machine control for image formation, image writing, paper feed control, status monitoring, and the like. It is configured.

  The host interface 311 performs interface control with the host machine 350. The program ROM 312 stores programs for editing image data and controlling the entire controller unit. The font ROM 313 stores standard fonts used for printing. The panel interface 314 performs interface control with the operation panel 319, and performs an interface with the user through the operation panel 319.

  The controller CPU 315 performs overall control of the controller unit 310. A RAM 316 and an option RAM 317 are memories in which data such as programs for processing and control and images are developed. The engine interface 318 is an interface between the controller unit 310 and the engine unit 330.

  The engine CPU 331 comprehensively controls the entire engine unit according to the control program. The controller interface 333 performs interface control with the controller unit 310 via the engine interface 318. The option interface 334 performs interface processing for the option 370.

  The input port 336 inputs various setting conditions related to image formation, the state of the apparatus, and the like. The output port 337 performs predetermined output processing for realizing the image forming process. The EEPROM 338 stores maintenance information and the like.

  The engine ROM 339 stores an engine control program and the like. The RAM 340 has a buffer register function and is used as a working memory.

  The DIPSW 342 performs switching setting such as a control mode. Each sensor 343 detects transport timing, temperature, toner concentration, and the like. Each motor 345 includes a main motor, a conveyance motor, and the like. Each clutch 346 drives / stops a paper feed roller, a registration roller, and the like. Each high-pressure process 347 performs high-voltage application such as charging, transfer, and development. In addition, an exchange unit 380 having an EEPROM 381 is connected to the engine unit 330.

  Next, the overall control operation of the laser printer of this embodiment will be described. FIG. 4 is a flowchart showing the flow of overall control of the laser printer of this embodiment.

  When the power is turned on, initial setting of each state is first performed (step S401), and the engine state is checked (step S402). Next, tasks (step S403) for performing interface control between the engine and the controller (reception of a paper feed command, reception of a resolution setting request, reception of a request for switching a paper feed port and a paper discharge port, etc.), a maintenance request and an error Control for checking the internal state of the engine itself, such as generation, task for performing sequence control such as paper feed timing and on / off of high voltage (Step S404), Queue task for managing information on printed paper (Step S405), printing A print control task (step S406) for controlling the request is performed according to the instructed operation, and thereafter this routine is repeated.

  On the other hand, independently of the main sequence, the interrupt module 332 (FIG. 3) executes interrupt processing for time monitoring and control for performing each processing, as will be described later.

  FIG. 5 is a flowchart showing the flow of interrupt control of the laser printer of this embodiment. After the power is turned on, this routine is entered every predetermined time set by the engine CPU 331 and necessary processing is performed. That is, when a predetermined time comes, it is checked whether or not interrupt control has occurred (step S501). If an interrupt has occurred (step S501 / YES), processing corresponding to the interrupt is performed (step S502). If no interrupt has occurred (step S501 / NO), the process ends.

  Next, the paper feed unit of the laser printer of this embodiment will be described. FIG. 6 is a perspective view (6-1, 6-2) and a side view (6-3) showing the outline of the paper feed unit of the laser printer of this embodiment.

  The paper feed unit includes guide plates 61 and 62 for setting and fixing paper in the paper feed unit in the vertical direction (printing direction) and the horizontal direction. Each of the guide plates is a movable mechanism that can be adjusted according to the paper size to be set. In the present embodiment, a paper presence sensor is provided at the longitudinal end of the guide plate 61 (the end of the paper in the traveling direction). 63 is installed. In this way, the paper presence sensor 63 moves in conjunction with the movement of the guide plate 61. For example, as shown in the perspective view (6-2), when the position of the guide plate 61 is moved, the paper presence / absence sensor 63 is also moved in conjunction with it, and is always located at the end of the paper. Further, as shown in the sectional view (6-3), the paper presence / absence sensor 63 is installed at a position where the presence / absence of paper can be determined in the shortest time after the start of paper feeding.

  Next, control for checking the presence of paper in the laser printer of this embodiment will be described. 7 and 8 are flowcharts showing the control flow of the paper presence / absence check of the paper feeding unit. FIG. 8 shows a flow after starting the paper presence check. In the software, the paper presence / absence sensor 63 is managed by polling or interruption as one of the input ports 336 (each sensor 343), but in order to reduce the load on the software, the sensor presence / absence sensor 63 is checked only when necessary. Check.

  First, it is determined whether or not there has been a print request from an upper layer such as a controller (step S701). If it is determined that there is a request (step S701 / YES), the process proceeds to a determination to start a subsequent paper feed operation (step S702). move on. If it is determined that the transfer paper feeding operation has started (step S702 / YES), the process proceeds to a paper presence check (step S703).

  When the paper presence / absence check is started, a monitoring period dedicated timer (hereinafter referred to as T $ C) having a counter role for counting the period of checking is cleared (step S801). Since the present invention is characterized in that a paper presence sensor is always installed at a position that can be detected earliest after the start of paper feeding, it is not necessary to continuously monitor after the start of paper feeding, and it is determined if monitoring is performed for a predetermined time. it can. It is necessary to set a timeout time for monitoring for a predetermined time.

  For example, when a machine with a paper feed line speed of 200 mm / second is configured so that the presence / absence of paper can be determined when the trailing edge of the paper moves 10 mm after starting the paper feed, 10 mm ÷ 200 mm / second, that is, 0.05 seconds after the paper feed starts. You can check the presence of paper. When T $ C is set to 5 as the timeout time, it is conceptually necessary to monitor the paper presence check 100 times within that period.

  Returning to the description of the flow again, after clearing T $ C, it is determined whether or not the time value T of T $ C is larger than the set value T1 (step S802). If T is larger than T1 (step S802 / YES), a timeout occurs (step S803). If T is equal to or less than T1 (step S802 / NO), T $ C is incremented (step S804), and the detection result of the paper presence / absence state is monitored (step S805).

  If the presence of paper is checked and the paper is present (step S805 / NO), the process returns to the determination of whether T exceeds T1 (step S802). On the other hand, the paper presence check determines that there is no paper. If no (NO in step S805), notification and processing of no paper are performed (step S806).

  After notifying that there is no paper, T $ C is cleared (step S807), and the process ends. Further, even after the time-out (step S803), T $ C is cleared and the process ends, and the initial state of the paper presence check is set.

  After the paper out notification is made, the controller unit 310 and the engine unit 330 cancel the image forming process such as writing and image forming, the image data editing process, and the like, and recover for the print request after the cancellation. Process.

  The advantage of being notified of paper-out information earlier is that the processing such as writing and image creation can be canceled and the time until the next printing can be shortened, and the load of the entire software for controlling and processing can be reduced. For example, this is conspicuous when a color tandem image forming apparatus such as Y, C, M, or K is used. Many of these image forming apparatuses have a configuration in which the start of writing of each color starts earlier than the start of paper feeding in terms of layout. The recovery process for the next printing of the machine can be performed quickly.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible.

  According to the above embodiment, the rear end can be automatically detected at any size by moving the sensor according to the paper size.

  Further, according to the above-described embodiment, the sensor that moves according to the paper size moves to the position of the last end in the paper feeding direction, so that when the final paper is fed, the paper feeding unit is out of paper. It is possible to detect that the status is earlier, and it is possible to perform recovery processing for the next printing earlier.

  Further, according to the above-described actual child form, the load on the entire software can be further reduced and the system load can be reduced by performing the check of the presence / absence of paper to the minimum necessary.

It is the schematic of the unit structure of the laser printer which concerns on embodiment of this invention. It is explanatory drawing which shows the conveyance relationship of the paper in the laser printer which concerns on embodiment of this invention, and the arrangement | positioning relationship of each mechanism. It is a block diagram which shows the structure of the control system of the laser printer which concerns on embodiment of this invention. It is a flowchart which shows the flow of the whole control in the laser printer which concerns on embodiment of this invention. It is a flowchart which shows the flow of the interruption control in the laser printer which concerns on embodiment of this invention. 1A and 1B are a perspective view and a side view showing an outline of a paper feed unit of a laser printer according to an embodiment of the present invention. It is a flowchart which shows the flow of control of the paper presence check in the laser printer which concerns on embodiment of this invention. It is a flowchart which shows the flow of control of the paper presence check in the laser printer which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 61, 62 Guide board 63 Paper presence sensor 110 Paper feed unit 310 Controller part 330 Engine part 332 Interrupt module 336 Input port 343 Each sensor

Claims (6)

Image forming means;
A paper feeding unit that accommodates the transfer paper and separates the transfer paper one by one and supplies it to the image forming unit;
A holding unit disposed in the sheet feeding unit and configured to hold the transfer paper accommodated in a uniform direction;
Detecting means for detecting the presence or absence of the transfer paper in the paper feeding means;
In an image forming apparatus comprising a control unit that performs control for monitoring a detection result by the detection unit,
The detecting means moves in the installation position according to the paper size of the transfer paper stored by the paper feeding means,
The image forming apparatus according to claim 1, wherein the control unit performs control to monitor a detection result of the detection unit for a predetermined time from the start of the supply operation by the sheet feeding unit.   The image forming apparatus according to claim 1, wherein an installation position of the detection unit is moved to a rear end portion in a direction in which the transfer paper is supplied by the paper supply unit. The holding means can move the arranged position according to the paper size,
The image forming apparatus according to claim 1, wherein the detection unit is installed in the holding unit.   The image forming apparatus according to claim 3, wherein the detection unit is installed in the holding unit that holds a side of the transfer paper perpendicular to a direction supplied by the paper feeding unit. Further comprising time measuring means for measuring the predetermined time,
The control means sets the time measuring means after the feeding operation by the paper feeding means is started and measures the time. When the time measurement result of the time measuring means has passed the predetermined time, the control means The image forming apparatus according to claim 1, wherein control for stopping monitoring of a detection result is performed.   When the feeding operation by the paper feeding unit continues after the control unit stops monitoring the detection result of the detection unit after the predetermined time has passed, the control unit again The image forming apparatus according to claim 5, wherein control for monitoring the detection result is performed.

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