JP2006021867A - Image forming device, and sheet feed control method for the image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely detect an upper limit position for a tray in raising and lowering the tray at the time of paper feed. <P>SOLUTION: In raising a sheet material stacking member on which sheet material is stacked to a paper feed position, if the sheet material stacking member is at a predetermined upper limit position or not is detected. In a case where it is determined that the sheet material stacking member is off the upper limit position continuously for prescribed time based on detection, the detection is continued, while the sheet material stacking member is raised till it is detected at the upper limit position. When it is detected reaching the upper limit position, raising the sheet material stacking member is stopped to be ready for paper feed. Detection error of an upper limit position detecting means on the sheet material stacking member due to vibration is thus prevented by continuous information of the upper limit position sensor for the prescribed time, so that sheet carrying performance is improved. The upper limit position of a supply paper tray is set correct. Supply paper jam due to over-raising the tray is prevented. Running efficiency of the image forming device is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a multifunction machine, and in particular, an image forming apparatus that forms an image by feeding sheet materials stacked and stored in a tray or the like when forming an image. The present invention relates to a sheet feeding control method of the apparatus.

An image forming apparatus usually includes a tray or the like on which a plurality of sheets are stacked, and includes a sheet feeding device that takes out sheets one by one from the stacked sheets.
In this paper feeding device, the paper is picked up one by one from the upper part of the paper by a roll or the like at the paper feeding position and fed. For this reason, in order to place the paper at a predetermined paper feeding position, means for raising and lowering the tray on which the paper is stacked is employed. In this elevating and lowering type paper feeding device, when elevating, a means for detecting that the paper on the tray has reached the paper feeding position is provided to control the elevating operation. In the detection, it is determined whether or not the upper surface of the sheet has reached the paper feeding position using a transmission type sensor, a reflection type sensor, an actuator, or the like, and the upper limit position of the tray is regulated by the detection.
If this raising / lowering control is not properly performed, the rise is insufficient or the rise is excessive. If the rise is insufficient, the upper surface of the sheet is not accurately positioned at the sheet feeding position, and thus there is a problem that feeding cannot be performed smoothly. Also, if the rise is excessive, the paper is pressed by the tray, causing paper jams and equipment damage.

However, in the paper feeding operation, vibration may occur in the tray when the paper is taken out, and as a result, it may not be possible to accurately detect whether the tray has reached the upper limit position.
By the way, in the circulation type document conveying device, there is known a method of improving paper discharge stackability by intentionally swinging at the time of transport, but also in this method, a decrease in detection accuracy due to swing is a problem. Yes. For this reason, a method for stopping detection for a predetermined time after the transport operation and avoiding erroneous detection has been proposed (see Patent Document 1).
Japanese Patent Laid-Open No. 5-39142

  However, in the above-described prior art, detection is stopped only for a fixed time, so that erroneous detection due to vibration cannot be avoided after a fixed time has elapsed. Further, since the ascent is always stopped for a certain time from the paper feeding operation, there is a problem that the operation is interrupted even when no vibration is generated, and the operation efficiency is poor.

  SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and an object of the present invention is to provide an image forming apparatus and a sheet material feeding control method of the apparatus that can improve the transportability by avoiding erroneous detection due to vibration during feeding. And

  In order to solve the above problems, among the image forming apparatuses of the present invention, the first invention is a sheet material stacking member for stacking sheet materials, a sheet material stacking member lifting and lowering means capable of moving up and down the sheet material stacking member, Sheet material stacking member upper limit position detecting means for detecting the sheet material stacking member at the upper limit position, and sheet material feeding that enables sheet material feeding to the image forming unit when the sheet material stacking member is in the vicinity of the upper limit position. The sheet material stacking member lifting / lowering means detects that the sheet material stacking member is not at the upper limit position continuously for a predetermined time by the sheet material upper limit detection position unit. The sheet stacking member is raised until it is detected that the upper limit position is reached.

  An image forming apparatus according to a second invention is characterized in that, in the first invention, the predetermined time can be changed.

  An image forming apparatus according to a third invention is characterized in that, in the first or second invention, the predetermined time is stored in a nonvolatile memory in a changeable manner.

  In the sheet material feeding control method of the image forming apparatus according to the fourth aspect of the invention, the sheet material stacking member is at a predetermined upper limit position when the sheet material stacking member for stacking the sheet material is raised to the sheet feeding position. The sheet material stacking member is in the upper limit position while continuing the detection when it is determined by the detection that the sheet material stacking member is not at the upper limit position for a predetermined time. The sheet material stacking member is stopped from rising when it is detected that the upper limit position has been detected, and is prepared for sheet feeding.

  According to a fifth aspect of the present invention, there is provided a sheet material feeding control method of the image forming apparatus according to the fourth aspect, wherein the predetermined time can be changed before the ascending operation of the sheet material stacking member.

  That is, according to the present invention, the sheet material stacking member is moved up and down by the sheet material stacking lifting unit, and the sheet material is sequentially taken out from the sheet material stacking member by the sheet material feeding unit when the sheet member is in the vicinity of the upper limit position. Are fed. The lifting operation control by the sheet material stacking member is performed based on the detection result by the sheet material stacking member upper limit position detecting means. That is, the detecting means detects that the sheet material stacking member is at the upper limit position. The detection result is output to the sheet material stacking raising / lowering means, and when it is detected for a predetermined time that the sheet material stacking member is not at the upper limit position, the lifting means lifts the sheet material stacking member. Start. The detection by the sheet material stacking member upper limit position detecting means is continued during the ascent, and the ascending operation is stopped by detecting that the sheet material stacking member has reached the upper limit position by the detecting means. Is done. By this operation, it is possible to avoid erroneous detection due to vibration that affects the detection operation within the predetermined time. This is because vibration does not continue for a long time, but attenuates in a short time and does not affect the detection operation, so if it is detected that it is not in the upper limit position only within a predetermined time, The detection accuracy is improved by estimating the influence of vibration or the like and excluding it from the detection result.

The sheet material is various transfer papers for image formation, and the material, size, and the like are not limited in the present invention. Also, the sheet material stacking member can be a detachable tray, a manual feed tray, a large capacity tray or the like.
Further, the sheet material stacking member lifting / lowering means for controlling the lifting / lowering of the sheet material stacking member can be configured by means for performing the lifting / lowering operation, for example, a motor or an actuator, and a control unit for controlling the same.

  The sheet material stacking member detecting means is not limited to a specific configuration as long as it can detect that the sheet material stacking member is at the upper limit position. For example, the sheet material stacking member detection means can be configured by a transmissive photosensor, a reflective photosensor, an actuator, or the like.

  In addition, the predetermined time used for the elevation control can be empirically obtained in consideration of the possibility of erroneous detection due to vibration. Further, the predetermined time can be changed depending on the detection result so as to reliably avoid erroneous detection.

As described above, according to the sheet material feeding control method of the image forming apparatus of the present invention, when the sheet material stacking member on which the sheet material is stacked is raised to the sheet feeding position, the sheet material stacking member is The sheet material stacking member is detected while continuing the detection when it is determined whether the sheet material stacking member is not at the upper limit position for a predetermined time by detecting whether or not the upper limit position is set. Is detected until the upper limit position is detected, and when the upper limit position is detected, the sheet material stacking member stops rising and prepares for sheet feeding. To prevent erroneous detection of the upper limit position detection means by continuous information of the upper limit position sensor for a predetermined time, and to improve detection accuracy and to prevent the sheet material stacking member from rising and shorting and over-raising, and to improve sheet conveyance performance But It becomes possible. Specifically, the upper limit position of the paper feed tray is optimized and no paper jam occurs due to excessive elevation of the lift tray. Further, no paper feed JAM is generated, and the running efficiency of the image forming apparatus is improved.
Note that by making the predetermined time changeable, detection accuracy can be further improved in response to setting changes between different models, variations in the same model, and the like.

  Further, according to the image forming apparatus of the present invention, the sheet material stacking member for stacking the sheet material, the sheet material stacking member lifting / lowering unit capable of raising and lowering the sheet material stacking member, and the sheet material stacking member at the upper limit position are provided. A sheet material stacking member upper limit position detecting unit to detect, and a sheet material feeding unit that enables sheet material feeding to the image forming unit when the sheet material stacking member is in the vicinity of the upper limit position. When the sheet lifting / lowering means detects that the sheet material stacking member is not at the upper limit position continuously for a predetermined time by the sheet material upper limit detection position means, it detects until the sheet material stacking member is at the upper limit position. Since the sheet stacking member is raised, the above-described operation can be obtained reliably and excellent detection accuracy can be obtained. The predetermined time can be stored in a non-volatile memory provided in the image forming apparatus in a changeable manner, and can be adjusted and changed to an optimal time by an operation of a service person.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing an overall mechanical configuration of an image forming apparatus according to the present invention.
The image forming apparatus 1 is provided with a scanner unit 30 including a CCD 31, an automatic document feeder (ADF) 33, a platen glass 34 on which a document is set, and an ADF document reading slit glass 35 on the upper side thereof. These constitute document reading means, and an operation unit 40 is provided in the vicinity of the platen glass 34.

  In addition, a paper feed tray 51 is disposed on the lower side of the image forming apparatus 1, and a large capacity paper feed tray 52 is disposed so as to be attached to the image forming apparatus 1. A second paper feed roller 53 is disposed at the transport destination of these paper feed trays to constitute a paper feed unit 50. Further, an image forming unit 60 composed of an LD 61 or the like is provided at a location downstream in the transport direction. A post-processing device (FNS) 70 is installed in the paper discharge area downstream of the image forming unit, so that desired post-processing (stapling, punching, etc.) can be performed on the transfer paper on which the image has been formed. Yes. The image forming unit 60 includes a photoconductor 62, a charger 63, a developing device 64, a fixing device 65 and the like in addition to the LD 61.

  The sheet feeding tray 51 and the large-capacity sheet feeding tray 52 can move up and down the tray on which transfer sheets are stacked. These transfer sheets correspond to the sheet material of the present invention, and the tray corresponds to the sheet material stacking member of the present invention. ing.

The outline of the paper feed tray 51 is shown in FIG.
The paper feed tray 51 is configured to load the transfer paper 100, and the paper feed tray 51 can be moved up and down by a lifting unit 150 driven by a lifting motor or the like. Above the paper feed tray 51, a paper feed roller 51a is arranged so that when the paper feed tray 51 is in the vicinity of the upper limit position, it is sequentially taken out from the upper surface side of the loaded transfer paper 100. Yes. A tray upper limit detection sensor 160 that detects that the transfer paper 100 has reached the paper feed position, that is, the paper feed tray 51 is at the upper limit position, is disposed above the paper feed tray 51. The tray upper limit detection sensor 160 constitutes a sheet material stacking member upper limit position detection unit of the present invention.
The tray upper limit detection sensor 160 may be any sensor as long as it can detect the upper end surface of the transfer paper at a predetermined position, and may be constituted by, for example, a transmission type or reflection type photosensor. In this embodiment, a reflective sensor composed of a light emitting part and a light receiving part arranged on the side of the transfer paper 100 is used.

Next, FIG. 3 is a block diagram for functionally explaining the main configuration of the image forming apparatus 1 of this embodiment, and will be described in detail below.
The image forming apparatus 1 includes a CPU 10 that controls the entire apparatus, and a nonvolatile memory 11, a RAM 12, a ROM 13, and a timer 14 are connected to the CPU 10. The CPU 10 controls each unit of the image forming apparatus 1 in response to a command from a system program or application program described later.

  The nonvolatile memory 11 stores data such as application programs for operating the CPU 10, setting data of the image forming apparatus 1, and process control parameters. Data for a predetermined time when the elevator 150 is controlled is also stored. The CPU 10 can read non-volatile data in the non-volatile memory 11, and can write desired data into the non-volatile memory 11 as non-volatile data and change the written data.

The RAM 12 temporarily stores data, is used as a work area when the CPU 10 operates, and is used for temporarily storing image data.
The ROM 13 stores data in a nonvolatile manner, and stores a system program for operating the CPU 11 and initial data that does not need to be changed.

  As described above, the scanner unit 30 is constituted by the CCD 31 or the like, and acquires image data by reading a document. The scanner unit 30 is connected to the CPU 10 and controlled by the CPU 10, and sends the acquired image data to the CPU 10. The CPU 10 receives the data and performs appropriate data processing.

  The operation unit 40 functions as a display unit that displays necessary information in addition to inputting setting input of the image forming apparatus. In order to achieve this, a touch panel (not shown) can be provided. The operation unit 40 is connected to the CPU 10 and controls input and display. Data input through the operation unit 40 is sent to the CPU 110 and subjected to predetermined processing.

  The sheet feeding unit 50 includes the sheet feeding tray 51, the large capacity sheet feeding tray 52, and the second sheet feeding roller 53, and further includes the sheet feeding roller 51a, the lifting unit 150, the lifting unit control unit 151, and the sensor. 160 and the like are included. The paper feed unit 50 is connected to the CPU 10 and performs various controls relating to paper feed.

Next, the basic operation of the image forming apparatus will be described.
When an appropriate setting is made by the operation unit 40 and an execution input such as copying is made, the CPU 10 receives the input and sets the machine state in accordance with the setting input or the setting data stored in the nonvolatile memory 11. The original is read by the unit 30. Image data obtained by the scanner unit 30 is subjected to appropriate data processing, stored in the RAM 12, and then sequentially sent to the image forming unit 60. The CPU 10 controls the paper feed unit 50 in preparation for image formation, takes out a transfer sheet, which is a sheet material, from a paper feed tray determined by settings and the like and conveys it to the image forming unit 60 to perform image formation. Thereafter, the transfer paper on which the image has been formed is post-processed by the post-processing device 70 as necessary, and then output.

The present invention is characterized by tray raising / lowering control in the sheet feeding unit 50 in the above procedure. This procedure will be described based on the flowchart of FIG.
With the start of copying, tray raising / lowering control is started before feeding. Here, whether or not the tray 51 is at the upper limit position is detected by the sensor 160 (step s1). Here, when it is detected that it is in the upper limit position, the tray lifting / lowering control is finished, and paper feeding can be performed. On the other hand, if it is not detected in step s1 that the tray 51 is at the upper limit position, the timer 14 counts (step s2). Note that the timer 14 is reset before the start of this process. Here, in the nonvolatile memory 11, a predetermined time (T2) for determining whether the tray upper limit has not been reached is determined in advance. It is determined whether the count time by the timer 14 has reached the predetermined time (T2) (step s3). Until the count time reaches T2, the process returns to the determination in step s1. If the upper limit position of the tray is detected when returning to step s1, the process is terminated in the same manner as described above. Such a situation is determined as a false detection because the sensor erroneously detected because vibration occurred in the tray or the like, but the detection time of the tray upper limit not being reached was within T2 hours. When it is confirmed in step s3 that the count time has reached T2 time, it is determined that the tray is not exactly at the upper limit position, and the tray 51 is raised (step s4). In this operation, the elevating unit control unit 151 is controlled by the CPU 10, and the elevating unit control unit 151 controls the operation of the elevating unit 150. As the tray 51 rises, the detection by the sensor 160 is continued, and it is determined whether or not the tray 51 has reached the upper limit position (step s5). Here, the rise continues until it is detected that the tray 51 has reached the upper limit position. When it is detected by the sensor 160 that the tray 51 has reached the upper limit position, the timer 14 is canceled (step s6), and the operation of the elevating unit 150 is stopped by controlling the elevating unit control unit 151, The raising of the tray is finished (step s7).
Whether or not the tray 51 is at the upper limit position can be accurately detected by the series of procedures described above, and an excessive rise of the tray can be prevented.

  A timing chart for the determination is shown in FIG. (A) As shown in the figure, in the present invention, even when the tray upper limit detection sensor detects that the upper limit has not been reached, if the detection time is not yet (T2 or less), the detection is not performed accurately. When T2 is reached, the tray raising / lowering section (in this figure, the tray raising / lowering motor) is operated to raise the tray as an accurate determination. When the tray is raised, the tray lift motor is stopped when the tray upper limit detection sensor detects that the upper limit has been reached. (B) The figure shows the timing chart by the conventional control method. The detection result of the detection sensor is not used within a certain time (T1) after the paper feeding, and the tray lifting / lowering motor is operated based on the detection result after a certain time has passed. In this control, even when the sensor erroneously detects that the tray has not been reached due to vibration, the tray lifting motor is operated to raise the tray after a certain period of time. That is, with this control method, an excessive rise in the tray is inevitable.

  As described above, the present invention has been described based on the above embodiment, but the present invention is not limited to the above description, and can be appropriately changed without departing from the present invention.

1 is a schematic diagram illustrating a mechanical structure of an image forming apparatus according to an embodiment of the present invention. Similarly, it is the expansion schematic of a paper feed tray. Similarly, it is a block diagram of a main configuration. Similarly, it is a flowchart which shows a tray raising / lowering control procedure. Similarly, it is a timing chart of tray lifting control in the present invention and a conventional example.

Explanation of symbols

1 Image forming apparatus 10 CPU
DESCRIPTION OF SYMBOLS 11 Nonvolatile memory 14 Timer 30 Scanner part 40 Operation part 50 Paper feed part 51 Paper feed tray 51a Paper feed roller 60 Image formation part 150 Tray raising / lowering part 151 Lifting part control part 160 Tray upper limit detection sensor

Claims (5)

A sheet material stacking member for stacking the sheet material, a sheet material stacking member lifting / lowering means capable of raising and lowering the sheet material stacking member, a sheet material stacking member upper limit position detecting means for detecting the sheet material stacking member at the upper limit position, A sheet material feeding unit that enables the sheet material to be fed to the image forming unit when the sheet material stacking member is in the vicinity of the upper limit position; and the sheet material stacking member elevating unit includes the sheet material upper limit detection position unit. When detecting that the sheet material stacking member is not at the upper limit position continuously for a predetermined time, the sheet stacking member is raised until it is detected that the sheet material stacking member is at the upper limit position. Image forming apparatus. The image forming apparatus according to claim 1, wherein the predetermined time is changeable. The image forming apparatus according to claim 2, wherein the predetermined time is stored in a nonvolatile memory in a changeable manner. When the sheet material stacking member for stacking the sheet material is raised to the paper feed position, it is detected whether the sheet material stacking member is at a predetermined upper limit position, and the sheet material stacking member continues for a predetermined time by the detection. If it is determined that the upper limit position is not reached, the sheet material stacking member is raised until it is detected that the sheet material stacking member is at the upper limit position while continuing the detection, and it is detected that the upper limit position has been reached. And a sheet material feeding control method for an image forming apparatus, wherein the sheet material stacking member is stopped from rising to prepare for sheet feeding. 5. The sheet material feeding control method for an image forming apparatus according to claim 4, wherein the predetermined time can be changed before the sheet material stacking member is raised.

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