JP2583329B2 - Sheet feeding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a sheet feeding apparatus such as a large-capacity cassette which is detachably attached to an apparatus having a sheet conveying mechanism such as an image forming apparatus and has a feeding function. It is about.

(Prior Art) Conventionally, an image forming apparatus such as a copying machine is provided with a sheet conveying mechanism for conveying a sheet-shaped transfer material. The transfer material is normally supplied to the sheet transport mechanism from a relatively compact paper feed cassette in which the transfer material is stored.

However, such a sheet cassette has a limit in the amount of transfer material that can be stored, and is not suitable for a large amount of copying. Therefore, a large-capacity cassette capable of accommodating a large amount of transfer material is provided in place of a normal paper feed cassette to deal with a large amount of copying.

(Problems of the prior art) By the way, in offices where copying machines and the like are frequently used, the number of copiers themselves is increased, but even if a plurality of copiers of the same manufacturer are installed, It is rare when multiple units of the same model are installed.

Therefore, even if a large-capacity cassette is moved between copiers and mounted in a large-volume copy as described above, it is mechanically compatible, but each of the large-capacity cassette and the transfer device of the copier main body is required. A paper jam may occur between the two due to the difference in the conveying speed.

For example, the large-capacity cassette is provided with a drive motor for driving the paper feed roller separately from the conveying device of the copying machine main body, and the driving speed of the large-capacity cassette cannot be changed. It can be applied only to a copying machine having a transport speed compatible with the above.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sheet feeding apparatus which solves the above-mentioned conventional disadvantages.

(Means for Solving the Problems) A sheet supply device according to the present invention is detachably mounted on an image forming apparatus main body, and supplies a sheet stored therein to a sheet conveying mechanism on the image forming apparatus main body side. And a pair of sheet sensors located between the supply means and the main body side sheet transport mechanism and arranged at a predetermined interval in the sheet transport direction so as to detect the trailing edge of the sheet after the start of transport by only the sheet transport mechanism. A sheet feeding speed on the side of the sheet feeding mechanism based on a detection result of the sheet sensor, and is calculated based on a feeding interval time previously set in the sheet feeding device and the detection result. Calculating means for calculating a difference from the appropriate supply interval time, and a preceding sheet conveyed by the sheet conveying mechanism based on the calculation result of the calculating means. Changing means for changing a supply interval time until a succeeding sheet bites into the sheet conveying mechanism so as to have a predetermined distance between a rear end of the sheet feeding device and a leading edge of a subsequent sheet supplied from the sheet feeding device; The supply interval time τ is changed by the changing means.τ = T2−T1 T1: Time required for the preceding sheet to be transported by the predetermined transport distance L1 T2: The leading edge of the sheet after the succeeding sheet is supplied by the supplying means It is characterized in that it changes to the time required until it is caught in the transport mechanism.

(Operation) As a result, the sheet feeding apparatus according to the present invention is configured such that the sheet conveyed by the sheet conveying mechanism passes through a pair of sheet sensors disposed at a predetermined interval based on the time of the sheet. The sheet transport mechanism of the transport mechanism is detected.
Then, based on the detected transport speed of the sheet transport mechanism, a difference between a supply interval time set in advance by the sheet supply unit and a time required to actually transport the sheet by the sheet transport distance by the sheet transport mechanism is calculated. Since the supply interval time of the sheet supply device can be changed, it is possible to prevent the subsequently supplied sheet from overlapping with the sheet transported by the sheet transport mechanism.

Therefore, even when the sheet feeding device is mounted on a sheet conveying mechanism having a different sheet conveying speed, sheets can be continuously supplied to the sheet conveying mechanism without paper jam.

(Embodiment) Next, an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a diagram showing a schematic configuration of a sheet conveying mechanism 1 and a sheet feeding device 2 of the present invention.

The sheet transport mechanism 1 is used as a part of a copying machine 3 as an example of an image forming apparatus. The copying machine 3 has an image forming unit 4, and mainly includes a main charger 6, a developing device 7, a transfer charger 8, which is arranged along the peripheral surface of the photosensitive drum 5.
A separation charger 9 and a cleaning device 10 are provided. Various optical devices 12 for guiding the image of the original placed on the contact glass 11 to the photosensitive drum 5 are disposed above the image forming unit 4. These optical devices 12 are provided with a light source for irradiating the original and a plurality of optical devices. And a reflection mirror. Reference numeral 20 denotes a control unit for operating the copying machine according to a predetermined procedure.
Image forming unit 4 and optical device 2 configured as described above
The image forming process is well known and will not be described.

The sheet conveying device 1 is provided below the image forming unit 4. The sheet transport mechanism 1 mainly includes a switch SW3 for detecting that a sheet-like transfer material is supplied from the sheet feeding cassette 13 and a sheet supply device 2 described later, and that the switch SW3 is turned on by the transfer material and the copy switch is turned on. And a paper feed roller 14 that starts rotating when pressed. Further paper feed rollers
A transport roller 24, a registration roller 15, a fixing device 16, and a discharge roller 17 are provided downstream of the printer 14, and constitute a transport path to the discharge tray 18.

The sheet feeding device 2 can be mounted on the mounting portion 19 of the copying machine 3 by moving the sheet feeding device 2 in the direction of arrow A.
In addition, it can be separated by moving in the direction opposite to the direction of arrow A.

The sheet feeding device 2 is configured as follows. That is, the image forming apparatus includes a storage unit 21 for storing the transfer material, and a supply roller 22 for feeding the transfer material from the storage unit 21 toward the sheet conveying mechanism as indicated by a broken line in FIG.
Transfer material detection sensors SW1 and SW2 for detecting the sheet conveyance speed by the sheet conveyance mechanism 1 are provided on the downstream side of 22. With these detection sensors SW1 and SW2, the transfer material is SW1,
The time required to pass between SW2 is obtained, and the sheet conveyance speed of the sheet conveyance mechanism 1 can be known from the relationship with the distance between SW1 and SW2 which is mechanically determined in advance. Reference numeral 23 denotes a sheet interval speed calculated by the sheet transport mechanism based on the transport speed of the sheet transport mechanism, based on the transfer speed of the transfer sheet as described above, or based on the transport speed of the sheet transport mechanism. This is a control unit for calculating the time required to convey the sheet for one minute and changing the supply interval time of the sheet supply device by calculating the difference from the supply interval time set in the sheet supply device. As is apparent from the above description, in this embodiment, the detecting means for detecting the sheet conveying speed is constituted by the detection switches SW1 and SW2 and a part of the control unit 23, and the changing means is constituted by a part of the control unit 23. Have been.

The operation of the sheet feeding device configured as described above will be described.

2 is an enlarged schematic view of a main part of FIG. 1, FIG. 3 is a flowchart showing a procedure for moving a sheet of a sheet feeding apparatus to an initial position, and FIG. FIG. 5 is a flowchart showing a procedure of an operation performed by the sheet conveying mechanism, and FIG. 5 is a flowchart showing a procedure of an operation performed by the sheet feeding apparatus to obtain a conveying speed of the sheet conveying mechanism.

When the sheet feeding device is mounted on a certain copying machine, the sheet conveying speed may be different from that of the copying machine which has been mounted so far, and if the sheet feeding device is used as it is, a paper jam may occur. Accordingly, in the present invention, as shown in FIG. 1, after the sheet feeding device 2 is mounted on the copying machine 3, the mode is changed to the measurement mode by operating the mode selection switch (not shown) of the sheet feeding device 2. When one copy is made on the copying machine 3 side in this state, the sheet feeding device 2 changes the sheet feeding interval, the sheet feeding speed, and the like as described later to obtain the sheet conveying speed of the mounted copying machine. This also enables the sheet to be conveyed well.

 Hereinafter, an embodiment of the present invention will be described.

First, after attaching the sheet feeding device 2 to the copying machine 3,
Preparation for moving the sheet of the sheet feeding device 2 to the initial position is performed. Explaining according to the flowchart of FIG. 3, after the power of the sheet feeding device 2 is turned on (step S
0), if it is determined in step S1 that SW1 is not turned on, the driving of the supply roller 22 is started because the transfer material in the sheet supply device 2 is not at the initial position (step S1).
3). The transfer material is transported to the supply roller 22 and the detection switch S
Turn on W1 and SW2 (steps S4 and S5) and turn on detection switch SW2.
When a predetermined time has elapsed after turning on (Step S6), the drive of the supply roller 22 is stopped (Step S7). In this case, the predetermined time is such that the leading end of the transfer material contacts the paper feed roller 14 of the copying machine 3 after the detection switch SW2 is turned ON, and the transfer material slightly deforms in front of the roller. At this time, the detection switch SW3 on the copying machine side is ON. Step S
1. When it is determined in step S2 that the detection switch is ON (both Y), it is assumed that the initial setting has been completed and no preparation is performed.

After the preparation for moving the sheet to the initial position is completed in this way, the sheet feeding device measures the conveying speed of the sheet conveying mechanism.

Explaining according to the flowcharts of FIGS. 4 and 5, the measurement mode is set in advance by operating a mode selection switch (not shown) of the sheet feeding apparatus 2. Then, when the copy switch of the copying machine is turned on (step S in FIG. 4).
8) If the detection switch SW3 provided on the copying machine side is not ON (N in step S9), the transfer material is
Therefore, the process is terminated, and the user is urged to perform preparations again as shown in FIG. In step S9
If SW3 is ON, the initial setting of the transfer material has been completed, so the paper feed roller 14 is driven (step S10), and the transfer material starts to be fed downstream. And the rear end of the transfer material is SW
After SW3 is turned off by exiting from step 3 (step S
11) It is determined whether or not a preset time has elapsed (step S12). If the time has elapsed, the feed roller 14 is stopped, and the copying machine 3 is used to determine the transport speed of the sheet transport mechanism. The operation on the side is terminated.

The above operation itself is not different from a normal one-sheet copy operation. During this time, only the paper feed roller 14 of the copying machine 3 rotates, and the supply roller 22 of the sheet feeder 2 does not rotate. Therefore, the transfer material is conveyed only by the paper feed roller 14 and is sent forward.

While the sheet conveying mechanism of the copying machine is performing the above operation, the sheet feeding device obtains the conveying speed of the sheet conveying mechanism as follows. That is, as shown in FIG. 4, the detection switch SW3 of the sheet feeding device 2 is turned ON from the rear end of the transfer material to the O position.
Before performing FF (step S11 in FIG. 4), the sheet feeding device 2
The detection switch SW1 of the sheet feeding device 2 is turned off at the rear end of the transfer material being conveyed forward from the printer (step S1 in FIG. 5).
Four). After the detection switch SW1 is turned off, a timer for counting time is started (step S15). Then, when the rear end of the transfer material turns off SW2 after turning off SW1 (step S1).
6) Stop the timer accordingly (step S
17). The transfer material conveyed by the sheet conveying mechanism 1 in this manner is detected by the detection switches SW1, SW
The time t passing between the two can be known. Step S18
Then, the transit time t between the detection switches SW1 and SW2 obtained as described above and the distance a between the detection switches SW1 and SW2 mechanically known in advance in the sheet feeding apparatus 2 (a (second
It is possible to know the sheet conveying speed V ₁ of the sheet conveying mechanism 1 from FIG see). The sheet conveying speed V ₁ based on, performs a calculation of parameters to be varied to control the feeding interval of the sheet feeding apparatus 2 (step S18). Since the paper feeding interval can be controlled in this manner, even when the sheet feeding device is replaced from a sheet conveying mechanism having a relatively high conveying speed to a copying machine having a sheet conveying mechanism having a relatively low conveying speed, the subsequent transfer material can be formed. There is no paper jam that catches up with the preceding transfer material.

The calculation performed in step S18 will be described with reference to FIG. 2, a preceding transfer material is fed forward by a feed roller 14 provided in the sheet transport mechanism 1 in a transfer material transport direction indicated by an arrow B in FIG. when sent to biting 14, the distance between the leading edge of the transfer material and a subsequent trailing edge of the transfer material preceding the set to be l _1. Copying this way remains if taking interval l ₁ even if the speed difference between the sheet conveying mechanism 1 and the sheet feeding device 2, transfer material preceding even keeping the transfer material also distances l ₁ the subsequent Since the paper is transported by the transport system of the machine 3, the paper can be transported without causing a paper jam. At the time of normal copying, when the detection switch SW1 is turned off at the rear end of the preceding transfer material as described later, the succeeding transfer material is conveyed by the supply roller 22 after a preset time τ. By adjusting, l ₁ can be made constant. That is, the preceding transfer material is conveyed by the paper feed roller 14, and from the time when the rear end reaches the detection switch SW1 (when the detection switch SW1 is turned off) to the time when the succeeding transfer material bites into the paper feed roller 14 The distance traveled is L ₁ = l + l ₁ where l is the distance from SW ₁ to the paper feed roller 14. Transfer material preceding the meantime, since the proceeding under the action of the paper feed roller 14 of the sheet conveying mechanism, by applying the transport speed V ₁ determined in step S18 in FIG. 5, required to travel the same Time T ₁ is Is required.

On the other hand the tip of the transfer material following the meantime, since the flow proceeds in the sheet feeding device 2 of the supply roller 22 the sheet conveyance mechanism 1 of the paper feed roller 14 time T ₂ commensurate to bite the conveying speed of the sheet feeding device 2 to the, if the conveying speed of the sheet supply apparatus 2 known in advance in the control unit within 23 and V _2, time T
₂ is It is. Note actual T ₂ are, the tip of the subsequent transfer material is subjected slight influence of the speed of the feed roller 14 when biting into the sheet feeding roller 14, but ignore it because little time.

From the above relationship, the waiting time of the rear end of the transfer material is SW1 from the OFF to the start of the driving of the supply roller 2 prior to the tau is, tau = T ₂ -T ₁ Therefore, It is given as the value _{V 2, a, l, l} 2 is known as a unique value in advance sheet supply apparatus, and since t is obtained in the measurement mode as described above, only the values l ₁ If it is determined and stored in the control unit 23, the setting parameters can be calculated only by the sheet feeding device 2 side. Therefore, even if the sheet feeding mechanism has any feeding speed, the sheet feeding device itself is automatically Can be handled by changing settings.

When the copying operation is performed using the waiting time τ obtained as described above, first, when the copy switch of the copying machine is turned on, the paper feed roller 14 starts driving and conveys the transfer material toward the front. And the rear end of this transfer material turns off the switch SW1
Then, the supply roller 22 starts driving after waiting for the time τ, and starts supplying the next transfer material. By doing so, it is possible to prevent the following transfer material from catching up with the preceding transfer material by adjusting the sheet feeding interval, thereby preventing a paper jam.

Furthermore, in this embodiment, an example in which the sheet transport mechanism is applied to a copying machine has been described. However, the present invention is not limited to this, and may be applied to a sheet transport mechanism used in a printer or the like.

(Effect) Since the sheet feeding apparatus of the present invention is configured as described above, the sheet feeding speed that is different depending on the model of the image forming apparatus main body to be mounted is actually detected, and the sheet feeding apparatus side is adjusted in accordance with the speed. Since the paper supply timing can be automatically adjusted, it is possible to set various parameters without performing a troublesome operation. In addition, since it can be adjusted to the actual transport speed of the image forming apparatus, it also enables fine adjustment, and enables the mounting of the sheet feeding device to a wide range of image forming apparatuses. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a sheet conveying mechanism and a sheet feeding device of the present invention, FIG. 2 is a schematic diagram showing an enlarged main part of FIG. 1, and FIG. FIG. 4 is a flowchart showing the procedure for moving the sheet, FIG. 4 is a flowchart showing the procedure of an operation performed by the sheet feeding device to determine the transport speed of the sheet transport mechanism, and FIG. It is a flowchart which shows the procedure of the operation | movement which a supply apparatus performs. DESCRIPTION OF SYMBOLS 1 ... Sheet conveyance mechanism 2 ... Sheet supply device 14 ... Supply roller 22 ... Supply roller 23 ... Control part 24 ... Conveyance roller

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-51429 (JP, A) JP-A-63-22442 (JP, A) JP-A-3-115027 (JP, A) JP-A 61-61 114945 (JP, A)

Claims (1)

(57) [Claims] An image forming apparatus which is detachably mounted on a main body of the image forming apparatus;
Supply means for supplying a sheet stored therein to a sheet conveyance mechanism on the image forming apparatus main body side, between the supply means and the main body side sheet conveyance mechanism,
A sheet feeding device comprising: a pair of sheet sensors arranged at a predetermined interval in a sheet conveying direction so as to detect a trailing edge of a sheet after the start of conveyance by only the sheet conveying mechanism. Calculating means for detecting a sheet conveying speed of the sheet conveying mechanism based on the sheet conveying mechanism, and calculating a difference between a supply interval time set in advance in the sheet feeding device and an appropriate supply interval time calculated based on the detection result; Based on the calculation result of the calculation means, the subsequent sheet is transported by the sheet transport mechanism such that a predetermined distance is provided between the trailing edge of the preceding sheet transported by the sheet transport mechanism and the leading edge of the subsequent sheet supplied from the sheet supply device. A change means for changing the supply interval time until the sheet is depressed, and the change means sets the supply interval time τ to τ = T2−T1 T2: The time required for the paper to be transported by the set transport distance L1 T2: The time required for the leading edge to be caught in the sheet transport mechanism after the succeeding paper is supplied by the supply means Feeding device.