JP2004345865A - Paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device capable of easily and stably feeding paper even if paper thickness or the like is changed. <P>SOLUTION: This paper feeding device is provided with a paper feeding base 1 for loading printing paper, a printing paper detection means 3 for generating a detection signal when the printing paper moves out of a region determined in advance in accordance with the reduction of height of printing paper, and an ascent means 2 for raising the paper feeding base 1 after receiving the detection signal from the printing paper detection means 3. This device is provided with a control means 5 for driving the ascent means 2 to raise the paper feeding base 1 only during set time corresponding to the number of printing papers fed within a predetermined time between the detection signals generated from the printing paper detection means 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet feeding device capable of stably feeding a printing sheet.

  2. Description of the Related Art Conventionally, a paper feeding device that feeds printing paper has been configured using a paper feeding tray on which printing paper can be loaded, and a transport unit that transports the printing paper on the paper feeding tray to a printing unit side. What was done is known. In the paper feeding apparatus according to the related art, a paper feeding table is configured to be able to move up and down or a transporting mechanism is configured to be able to move up and down in order to continuously feed printing paper. It is known (for example, see Patent Document 1).

  Further, among the paper feeders according to the above-mentioned conventional technology, when the paper feed tray is configured to be able to move up and down, when the printing paper is continuously fed, the rising amount of the paper feed tray is fixed. Are common. That is, in such a paper feeder according to the related art, the rising amount of the paper feed tray is set to a predetermined value (for example, 80 msec) by the fixed timer, and the printing paper stacked on the paper feed tray is When the height is detected and the height of the printing paper becomes a predetermined height, the paper feed table is configured to rise for a rising time required for a predetermined value determined by a fixed timer.

  Further, in another related art, there is also known a sheet feeding device including an adjustment timer capable of adjusting the amount of rise of the sheet feeding table described above. In such a paper feeder, the operator adjusts the adjustment timer (determines the rising amount) based on the thickness of the printing paper or the like. Then, the height of the printing paper stacked on the paper feed tray is detected, and when the height of the printing paper reaches a predetermined height, the paper is fed by an increasing amount according to a value determined by an adjustment timer. The platform is configured to rise.

JP 2000-344359 A

  However, the conventional technique has the following problems. First, in a sheet feeding device that determines the amount of rise of the sheet supply table using a fixed timer, the amount of rise of the sheet supply table is determined irrespective of the paper thickness and the like. There was a problem.

  Further, in the case of a sheet feeding device that determines the amount of rise of the sheet feeding table using the adjustment timer, the operator judges based on the machine rotation speed (the rotation speed of the driving unit that raises the sheet feeding table) and the paper thickness. It is necessary to adjust the value of the adjustment timer each time. However, there is a problem that this adjustment requires experience and intuition and cannot be easily performed. Furthermore, even if the adjustment is performed once, if the rotation speed of the machine, the paper thickness, etc. are changed, it is necessary to perform the adjustment again in order to prevent a paper feeding failure, and such adjustment work is complicated. There was a problem that is.

  Therefore, the present invention has been made in order to solve the above-described problems of the related art, and a paper feeding device capable of easily performing stable paper feeding even when the paper thickness or the like is changed. The task is to provide.

  The present invention provides a paper feed tray on which printing paper can be stacked, printing paper detecting means for issuing a detection signal when the printing paper moves out of a predetermined area as the height of the printing paper decreases, and the printing paper Lifting means for raising the paper feed table after receiving a detection signal from the detection means, wherein the number of sheets of printing paper fed within a predetermined time between detection signals issued from the printing paper detection means Control means for driving the raising means so as to raise the paper feed table for a set time according to the following.

  According to such a configuration, for example, the elevating means is controlled based on the number of sheets fed within the immediately preceding predetermined time, whereby the sheet feeding table moves up and down while being automatically controlled. . That is, according to the present invention, even when a large amount of printing paper is reduced and the state at the start of paper feeding and the state thereof greatly change, the elevating means is controlled based on the number of sheets fed immediately before. Since the control is performed, it is possible to set a more appropriate amount of elevation of the sheet feeding table in a continuous sheet feeding state.

  Further, it is preferable that the control means has a table for determining the set time.

  Preferably, the control means has a program for calculating the set time.

  ADVANTAGE OF THE INVENTION According to the paper feeder which concerns on this invention, even if a paper thickness etc. are changed, a paper feed failure etc. are eliminated and the paper feeder which can implement a stable paper feed easily can be obtained. Further, even an inexperienced operator can obtain a sheet feeding device capable of realizing stable sheet feeding regardless of the sheet thickness or the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First embodiment>
FIG. 1 is a schematic block diagram of a sheet feeding device according to the first embodiment of the present invention. As shown in FIG. 1, a sheet feeding device according to the present embodiment includes a sheet feeding table 1, an elevating means (equivalent to “elevating means” of the present invention) 2 for elevating and lowering the sheet feeding table 1, A paper height detection sensor 3 (corresponding to the "printing paper detecting means" of the present invention) for detecting the height of the printing paper loaded in 1; paper thickness input for inputting the paper thickness of the printing paper to be used The control means 5 controls the elevating state of the sheet supply table 1 based on various information.

  The paper feed table 1 according to the present embodiment is configured to be able to stack a large number of printing papers, and is configured to be able to move up and down by the elevating means 2 in a state where the printing papers are stacked. The elevating means 2 includes a sheet feeding motor 21 for supplying a driving force to the sheet feeding table 1 via a chain or the like so as to move the sheet feeding table 1 up and down, and drives the sheet feeding table motor 21 at an appropriate timing. It is configured using a paper feed table motor drive circuit 22 configured to send a start signal (“ON” signal) or a drive stop signal (“OFF” signal).

  The paper height detection sensor 3 is configured to detect the height of the printing paper stacked on the paper feeding table 1, that is, the height from the paper feeding table 1 to the top of the printing paper. And a proximity switch (not shown) for detecting a displacement of the contact portion (a reduction amount of the printing paper). According to such a configuration, the contact portion is displaced (falls) with a decrease in the printing paper, and the proximity switch is moved up and down in response to the displacement of the contact portion. When the proximity switch moves (for example, when the proximity switch changes from the ON state to the OFF state), a predetermined detection signal (the “detection signal in the printing paper detection means” of the present invention) from the paper height detection sensor 3. ) Is sent to the control means 5.

  The paper thickness input means 4 is configured to be capable of inputting the thickness of the printing paper to be used, and is configured using, for example, a keyboard or a channel. That is, in the present embodiment, the thickness of the printing paper to be used (loaded on the paper feed tray 1) is input using the paper thickness input means 4, and information on the paper thickness will be described later. (Hereinafter, also referred to as “paper thickness information”) and the like, and the amount of elevation of the paper feed table 1 is appropriately controlled.

  The control means 5 includes a microprocessor 51 for performing arithmetic processing and the like, a ROM 52 for storing data and a predetermined program (arithmetic formula or table, etc.), a RAM 53 for storing various information relating to printing paper and the number of machine revolutions, a microprocessor, It is configured using an interface 54 and the like that mediate exchange of various signals between the control unit 51 and a device provided outside the control unit 5.

  As shown in FIG. 1, in the present embodiment, the paper thickness information input by the paper thickness input means 4 is stored in the RAM 53 via the interface 54 constituting the control means 5. Further, as will be described later, since a table that determines the rise time (rise amount) of the paper feed tray based on the paper thickness is stored in the ROM 52, the rise time of the paper feed tray 1 is automatically determined based on the paper thickness information. Is determined. Then, in the present embodiment, after the feeding of the printing paper on the paper feeding table is started, a detection signal corresponding to the usage of the printing paper is sent from the paper height detection sensor 3 via the interface 54 to the micro height sensor. The microprocessor 51 sends a predetermined signal (such as an ON / OFF signal) to the paper feed table motor drive circuit 22 based on the detection signal and the paper thickness information.

  Next, FIG. 2 shows a flowchart when the paper feeder according to the present embodiment performs automatic control of the paper feed tray. FIG. 3 shows an example of a table (a table that defines the relationship between the paper thickness and the rise time) stored in the ROM in the present embodiment. Hereinafter, the automatic control of the sheet feeding table in the sheet feeding apparatus according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 2, in the present embodiment, when starting paper feeding in the paper feeding device, first, the paper thickness of the printing paper loaded on the paper The thickness is input (step S201).

The input paper thickness is stored in the RAM 53 via the interface 54. Since a table relating to the paper thickness (mm) and the rise time (msec) as shown in FIG. 3 is stored in the ROM 52 in advance, the microprocessor 51 corresponds to the input paper thickness from the table. rise time (the amount of increase in the timer value) T ₁ is determined that (step S202). For example, if the paper thickness input is 0.20mm, the timer value T ₁ is determined to 120 msec.

Now, input of the paper thickness, as described above, and after the determination of the timer value T ₁ based on is made which, in the control unit 5, the state to determine whether to start the paper feed (standby state) (Step S203) By turning on the start button or the like of the printing apparatus or the sheet feeding apparatus (Yes in S203), the feeding of the printing paper in the sheet feeding apparatus is started.

  When the feeding of the printing paper is started, the microprocessor 51 monitors the detection signal from the paper height detection sensor 3 (Step S204). Then, when an “OFF” signal is issued from the paper height detection sensor to the microprocessor 51 (“OFF” in S204), the processing from step S205 is performed, and the processing from the paper height detection sensor to the microprocessor is performed. If an “ON” signal is issued to 51 (“ON” in S204), the processing from step S208 is performed.

  The contact portion forming the paper height detection sensor 3 is in contact with the upper part of the printing paper on the paper feed table 1 at the start of paper feeding, and in this state, as described above, the displacement of the contact portion can be detected. The proximity switch is in the “ON” state. Since the contact portion is displaced (down) as the printing paper is reduced, in the present embodiment, the proximity switch is moved out of a predetermined area in accordance with the displacement of the contact portion, so that the proximity switch is moved. The switch is configured to be in the “OFF” state. That is, if the usage amount of the printing paper is within the predetermined amount after the start of the feeding of the printing paper, the proximity switch maintains the “ON” state. When a signal is issued and the usage amount of the printing paper exceeds a predetermined amount, the proximity switch is set to the “OFF” state, and the “OFF” signal is issued from the paper height detection sensor 3 to the microprocessor 51.

Now, if the paper height detection sensor 3 "OFF" signal is generated ( "OFF" at S204), if the timer value T ₁ defined in the previous step S202 is "0" It is determined whether or not it is (step S205).
If the timer value T ₁ is “0” (Yes in S205), the processing from step S208 described below is performed. If the timer value T ₁ is not “0” (No in S205), An “ON” signal is transmitted from the microprocessor 51 to the paper feed board motor drive circuit 22 via the interface 54 (step S206). When an “ON” signal is transmitted to the paper feed table motor drive circuit 22, the paper feed table motor 21 is driven based on this signal, and the paper feed table 1 starts to rise. After the "ON" signal is transmitted to the paper feed table motor driving circuit 22, the subtraction timer value T ₁ (count down) is started (step S207), the processing of step S205 and subsequent is repeated.

On the other hand, when the "ON" signal is issued from the paper height detection sensor 3 ( "ON" at S204), and if the timer value T _1, as described above becomes "0" (in S205 (Yes), the microprocessor 51 issues an "OFF" signal to the paper feed table motor drive circuit 22 (step S208). Therefore, when the paper feed table motor 21 is in the driving state (when the process reaches S208 via S205), the paper feed table motor 21 is stopped (the lifting of the paper feed table 1 is stopped), and the paper feed is stopped. When the table motor 21 is in the stopped state (when the process directly proceeds from S204 to S208), the stopped state of the sheet feeding table motor 21 is maintained.

  Then, the control means 5 determines whether or not to stop the paper feeding (step S209). If the stop button of the printing apparatus or the paper feeding apparatus is turned on (Yes in S209), the feeding of the printing paper is performed. If the paper is finished, otherwise (No in S209), the processing after step S204 is performed.

In other words, according to the present embodiment, for example, if the timer value T ₁ is determined to be 120 msec, based on the detection signal of the paper height detection sensor 3, The paper feed table 1 is raised by driving the paper feed table motor 21 for a time of 120 msec.

  The paper feeding device according to the present embodiment is configured and functions as described above, and therefore, the following effects can be obtained.

  That is, according to the present embodiment, since the rising time is configured to be automatically determined based on the paper thickness, the rising amount (the rising time) is not constant as in the related art, but is used. It is possible to provide a lift amount suitable for printing paper. Therefore, it is possible to greatly reduce the rate of occurrence of paper feeding failure.

  Further, according to the present embodiment, since the appropriate rise time is determined only by inputting the paper thickness (basically known value) of the printing paper to be used, an inexperienced operator can be used. Even when used, stable paper feed can be easily realized.

<Second embodiment>
FIG. 4 is a schematic block diagram of a sheet feeding device according to the second embodiment of the present invention. As shown in FIG. 4, the sheet feeding device according to the present embodiment includes a sheet feeding table 1, an elevating unit 2 for moving the sheet feeding table 1 up and down, and a height of the printing paper stacked on the sheet feeding table 1. Paper height detecting sensor 3 (corresponding to “printing paper detecting means” of the present invention) for detecting the number of paper sheets fed, and sheet feeding number measuring means 6 (“measuring means” of the present invention) for measuring the number of fed print papers And control means 5 for controlling the elevating state of the sheet supply table 1 based on various information.

  The paper feed table 1 according to the present embodiment is configured to be able to stack a large number of printing papers, and is configured to be able to move up and down by the elevating means 2 in a state where the printing papers are stacked. The elevating means 2 includes a sheet feeding motor 21 for supplying a driving force to the sheet feeding table 1 via a chain or the like so as to move the sheet feeding table 1 up and down, and drives the sheet feeding table motor 21 at an appropriate timing. It is configured using a paper feed table motor drive circuit 22 configured to send a start signal (“ON” signal) or a drive stop signal (“OFF” signal).

  The paper height detection sensor 3 is configured to detect the height of the printing paper stacked on the paper feeding table 1, that is, the height from the paper feeding table 1 to the top of the printing paper. And a proximity switch (not shown) for detecting a displacement of the contact portion (a reduction amount of the printing paper). According to such a configuration, the contact portion is displaced (falls) with a decrease in the printing paper, and the proximity switch is moved up and down in response to the displacement of the contact portion. When the proximity switch moves (for example, when the proximity switch changes from the ON state to the OFF state), a predetermined detection signal (the “detection signal in the printing paper detection means” of the present invention) from the paper height detection sensor 3. ) Is sent to the control means 5.

  4 measures the number of print sheets fed from the sheet supply table 1 and sends the measured value (number) to the microprocessor 51 and the RAM 53 via the interface 54. It is configured to be transmitted to. Specifically, it is configured to measure and transmit the number of print papers between detection signals issued from the paper height detection sensor 3.

  Further, in the sheet feeding apparatus according to the present embodiment, a table for determining a rising time (elevating amount) of the sheet feeding table based on the number of sheets fed, which will be described later, is stored in the ROM 52 constituting the control means 5. Therefore, in the present embodiment, the rise time of the paper feed table 1 is automatically determined based on the number of paper feeds measured by the paper feed number measurement means 6 and stored in the RAM 53.

In the present embodiment, a reference rising time T ₀ is set as the rising time T ₂ at the start of sheet feeding (T ₂ = T ₀ ). The reference rise time T ₀ may be stored in the RAM 53, for example, and may be changeable as needed. The reference rise time T ₀ may be stored in the ROM 52, for example.

Next, FIG. 5 shows a flowchart when the automatic control of the paper feed tray is performed in the paper feed device according to the present embodiment. Also, FIG. 6 is a diagram showing an example of a table (table that defines the relationship between the number of fed sheets and the rise time T ₂₎ which in this embodiment is stored in the ROM.
Hereinafter, the automatic control of the sheet feeding table in the sheet feeding apparatus according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 5, in the present embodiment, when the start of the printing device or the paper feeding device is turned on, the feeding of the printing paper stacked on the paper feeding table 1 is started (step S501). at Yes), a predetermined reference rise time as rise time T ₂ of the paper feed table 1 T ₀ (reference increase amount) is set (step S502). As the reference rise time T ₀ , for example, about 100 msec is set.

  When the feeding of the printing paper is started, the microprocessor 51 monitors the detection signal from the paper height detection sensor 3 (step S503). Then, when an “OFF” signal is issued from the paper height detection sensor to the microprocessor 51 (“OFF” in S503), the processing from step S504 is performed, and the processing from the paper height detection sensor to the microprocessor is performed. If an “ON” signal is issued to 51 (“ON” in S503), the processing from step S507 is performed.

Now, if the paper height detection sensor 3 "OFF" signal is generated ( "OFF" at S503), whether the timer value T ₂ is "0" is judged (step S504 ). Immediately after the start of sheet feeding, a determination is made based on the timer value T ₂ (= T ₀ ) determined in the previous step S502. If the timer value T ₂ is “0” (Yes in S 504), after the measured value of the number of fed sheets is reset (Step S 507), the processes in and after Step S 508 described below are performed, and the timer value T _{If 2} is not “0” (No in S504), an “ON” signal is transmitted from the microprocessor 51 to the paper feed board motor drive circuit 22 via the interface 54 (step S505). When an "ON" signal is transmitted to the paper feed table motor drive circuit 22, the paper feed table motor 21 is driven based on this signal, and the paper feed table 1 starts to rise. After the "ON" signal is transmitted to the paper feed table motor driving circuit 22, the subtraction timer value T ₂ (count down) is started (step S506), the processing of step S504 and subsequent is repeated.

On the other hand, when the “ON” signal is output from the paper height detection sensor 3 (“ON” in S503), as described above, the timer value T ₂ becomes “0” (in S504). If the measured value of the number of fed sheets is reset (S507), the microprocessor 51 issues an "OFF" signal to the feeder board motor drive circuit 22 (step S508). Therefore, when the paper feed table motor 21 is in the driving state (when S508 is reached via S504 and S507), the paper feed table motor 21 is stopped (the lifting of the paper feed table 1 is stopped), and When the paper feed board motor 21 is in the stopped state (when the process directly proceeds from S503 to S508), the stopped state of the paper feed board motor 21 is maintained.

  Next, the control unit 5 determines whether or not to measure the number of fed sheets (step S509).

Immediately after the start of sheet feeding printing paper, as described above, the timer value T ₂ are, because they are set to the reference rise time T _0, there is no need to determine the timer value T ₂ based on the processing to be described later . Therefore, in this embodiment, if it is immediately after the paper feed started, measurement of the number of fed sheets is not performed (although done measurements virtually without determining the timer value T ₂ in the measured value ) (No in S509), the process proceeds to step S503. That is, for the first increase in the paper feed table 1, the reference rise time T ₀ as a timer value T ₂ is used.

After the sheet feeding table 1 has been raised at least once, the number of fed sheets is measured (Yes in S509), and an addition process of the measured number of fed sheets is performed (step S510). This sheet number is stored in the RAM 53 of the control means 5 as needed. Since a table relating to the number of sheets fed and the rise time (msec) as shown in FIG. 6 is stored in the ROM 52 in advance, the microprocessor 51 uses the table from the table to correspond to the number of sheets fed in the RAM 53. The determined rise time (timer value T ₂ ) is determined (step S511). Then, the rise time timer value T ₂ are stored in the RAM 53.

Here, each time the number of sheets fed and the rise time timer value T ₂ are added and obtained from the table, they are overwritten at a predetermined location in the RAM 53, and are stored in the RAM 53 at that time in step S 504. rise time timer value T ₂ is used. The determination as to whether or not the “sheet feeder 1 has been raised at least once” is performed, for example, based on the state of a flag in a predetermined storage location in the RAM 53. That is, if the sheet feeding table 1 is raised once, a flag is set and the state is maintained until the sheet feeding is stopped.

  Then, the control means 5 determines whether or not to stop the paper feeding (step S512). If the stop button or the like of the printing apparatus or the paper feeding apparatus is turned on (Yes in S512), the feeding of the printing paper is performed. When the paper is finished, otherwise (No in S512), the processing after step S503 is performed.

That is, according to the present embodiment, increase in the paper feeding table 1 immediately after the start feeding the detection signal (OFF signal) from the paper height detecting sensor 3, and is performed based rise time using the T _0. After that, the number of sheets fed is measured until the detection signal (OFF signal) from the sheet height detection sensor 3 is transmitted again after the rising of the sheet feeding table 1 is stopped. and rise time T ₂ based on the value is acquired from the table (see FIG. 6), the detection signal from the paper height detection sensor 3 (OFF signal), and with a rise time T _2, increase in the paper feeding table 1 Is performed.

Therefore, for example, the reference rise time T ₀ is 100 msec, and after the rise of the paper feed table 1 based on the reference rise time T ₀ is completed, the detection signal (OFF signal) from the paper height detection sensor 3 is transmitted. If the number of printing paper is fed in until the was four, the rise time T ₂ is determined to 160 msec, the ascent of the next paper feeding table 1, the value (160 msec) is used . Then, in this embodiment, (at S512 Yes) sheet feeding stops and until, the addition processing of the number of fed sheets (S510) and elevated determining the time T ₂ based thereon (S511) and the like are performed, and continuous in the sheet feeding state it is always configured to obtain a proper rise time T _2.

In the present embodiment, after the sheet feeding table 1 is lifted once, the sheet feeding number is reset in step S507, and the value of the sheet feeding number in the RAM 53 is cleared. since the process of adding the new number of fed sheets (S510) is started, the value of the sheet number of sheets and rise time T ₂ in the RAM53 becomes to be newly overwritten process.

  The paper feeding device according to the present embodiment is configured and functions as described above, and therefore, the following effects can be obtained.

  That is, the sheet feeding device according to the present embodiment is configured so that the rising time of the sheet feeding table 1 is automatically determined based on the number of sheets fed within the immediately preceding predetermined time. At that time, an appropriate rising time is selected according to the thickness of the printing paper stacked on the paper board 1, the paper feeding speed (mechanical speed) at that time, or the remaining amount (weight) on the paper board 1. It will be. Therefore, according to the present embodiment, similarly to the first embodiment, it is possible to greatly reduce the rate of occurrence of paper feeding failure.

  Further, according to the present embodiment, since an input operation or the like is not particularly required, stable paper feeding can be easily realized even when an inexperienced operator uses the apparatus.

<Third embodiment>
FIG. 7 is a flowchart showing a case in which the paper feeder according to the third embodiment of the present invention performs automatic control of the paper feed tray. The paper feeder according to the present embodiment has basically the same configuration as that of the second embodiment (see FIG. 4), and the control method of the paper feed table is substantially the same. Therefore, in the following, referring to FIG. 4, detailed description of the same configuration and control method as in the second embodiment will be omitted, and portions different from the second embodiment will be mainly described.

  Steps S701 to S710 and step S712 shown in FIG. 7 are the same as steps S501 to S510 and step S512 shown in FIG. 5, respectively. Are different in the part related to the processing in step S711 (S511 in FIG. 5). Specifically, in the second embodiment, the rising time is determined using a table indicating the relationship between the number of fed sheets and the rising time, but in the present embodiment, an appropriate rising time is determined from the number of fed sheets. Is calculated using a program for calculating the following equation.

That is, in the present embodiment, a program for calculating an appropriate rise time (rise amount) T ₃ of the paper feed table 1 from the number X of print paper fed is stored in the ROM 52 constituting the control means 5. I have. As such an arithmetic program, for example, a program using the following mathematical formula can be mentioned.
(Equation 1) T ₃ = (300 / X) +60
T ₃ : Appropriate rise time (lift amount) of paper feed table 1
X: Number of paper sheets fed

Accordingly, in step S711, the microprocessor 51 forming the sheet feeding apparatus according to the present embodiment uses the number of sheets fed in the RAM 53 and the calculation program in the ROM 52 to set an appropriate rise time timer value T ₃ . Can be determined. Rise time timer value T ₃ calculated in step S711 is overwritten at a predetermined position from time to time RAM 53, in step S704, the rise time timer value T ₃ that is stored in the RAM 53 is used when the .

In a third embodiment shown in FIG. 7 shows the case of determining the appropriate next rise time timer value T ₃ for each increase of one of the paper feed table 1, the present invention is the construction However, the present invention is not limited to this.
Therefore, for example, the number of sheets fed of the printing paper when the sheet feeding table 1 is raised a plurality of times (about three to five times) is measured, and the number of sheets fed each time is calculated. by using the calculation program stored in the ROM 52, it may determine the rise time timer value T ₃ suitable paper feeding table 1.

  Since the sheet feeding device according to the present embodiment is configured and functions as described above, substantially the same effects as those of the above-described second embodiment can be obtained.

Further, according to this embodiment, since the calculation program is used, can be compared to the case of using a table, and controls the paper feed table 1 to determine the rise time timer value T ₃ with higher accuracy It becomes.

Further, in the present embodiment, the average number of sheets fed is calculated based on the number of sheets fed when the sheet feeding table 1 is raised a plurality of times (about three to five times). it is also possible to determine the rise time timer value T ₃ of the table 1. According to such a configuration, even if there is an error in the measurement of the number of fed sheets or the like, the error is absorbed by taking the average value, and more stable automatic control of the sheet feeding table 1 can be performed. .

This method can also be applied to the above-described second embodiment. That is, based on the paper feed quantity of the plurality of paper feed table 1 at elevated calculates the average feeding quantity, by using the average feed quantity and the table may be determined rise time timer value T ₂ .

<Other embodiments>
The present invention is not limited to the above embodiments, and various changes other than those described above can be made without departing from the gist of the present invention.

  Therefore, for example, in each of the above-described embodiments, the rising speed of the paper feed tray 1 is not particularly defined, but the rising speed is controlled, for example, by using an inverter or the like in the paper feed tray motor drive circuit 22. Can be. If the paper thickness is large or the number of paper feeds is small, the ascending speed is increased. It is possible to do.

Further, in the above-described second and third embodiments, the configuration having no paper thickness input means has been described. However, the present invention is not limited to this configuration, and the paper thickness input means may be added as necessary. Thus, the sheet feeding devices according to the second and third embodiments may be configured.
According to this configuration, since the paper thickness is input as the print paper information, the information can be used to automatically control the paper feed table 1 with higher accuracy.

FIG. 1 is a schematic block diagram of a sheet feeding device according to a first embodiment of the present invention. 3 is a flowchart when automatic control of a sheet feeding table is performed in the sheet feeding device illustrated in FIG. 1. 2 is an example of a table that defines a relationship between a paper thickness and a rise time stored in a ROM of a control unit illustrated in FIG. 1. FIG. 7 is a schematic block diagram of a sheet feeding device according to a second embodiment of the present invention. 5 is a flowchart when automatic control of a sheet feeding table is performed in the sheet feeding device illustrated in FIG. 4. 5 is an example of a table that defines a relationship between a paper thickness and a rise time stored in a ROM of a control unit illustrated in FIG. 4. 9 is a flowchart when automatic control of a sheet feeding table is performed in the sheet feeding apparatus according to the third embodiment of the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Paper feed table 2 ... Elevating means 3 ... Paper height detection sensor 4 ... Paper thickness input means 5 ... Control means 6 ... Paper feed number measuring means 21 ... Paper feed board motor 22 ... Paper feed board motor drive circuit 51 ... Micro Processor 52 ROM
53 ... RAM
54 ... Interface

Claims (3)

A paper feed tray on which printing paper can be loaded, a printing paper detecting means for issuing a detection signal when the printing paper moves outside a predetermined area as the height of the printing paper decreases, and Lifting means capable of raising the paper feed table after receiving the detection signal,
Control means for driving the lifting means so as to raise the paper feed table for a set time corresponding to the number of sheets of printing paper fed within a predetermined time between detection signals issued from the printing paper detection means. A sheet feeding device, which is provided. 2. The sheet feeding device according to claim 1, wherein the control unit has a table that determines the set time. 2. The sheet feeding device according to claim 1, wherein the control unit has a program for calculating the set time.

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