JPH04256631A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent malfunction of an image forming device and protect the circuits therein. CONSTITUTION:In standby mode when sheets P of a large capacity sheet feeding device 25 are not used, a tray 61 on which the sheets P are placed is held stopped in the condition a little sunk, and an actuator as a sensor of a level sensing device 65, which performs sensing of the sheet level, is kept in the retreated position.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine having a paper feeding device in which paper is moved up and down by a tray.

0002

[Prior Art] Conventionally, copiers, etc. have large-capacity paper feeders (
LCF) is provided. With this kind of paper feeding device,
Paper is placed on a tray that is moved up and down by an elevator mechanism, and a paper feed roller is always in contact with the topmost paper on the tray to enable paper feeding.

In this case, the topmost paper on the tray is set at a paper feeding position by driving an elevator mechanism in response to a detection signal obtained from the movement position of an actuator that moves in conjunction with the paper feeding roller. It is now possible to do so.

However, a photo interrupter has been used as a detection means for detecting the position of the paper. Since the output of this photointerrupter is an analog output, the movement of the actuator that mechanically turns this photointerrupter on and off affects the change in output voltage. ) The voltage level (intermediate level) in the area that is not guaranteed at the threshold level may enter, causing the CMOS to malfunction, or due to an assembly error, etc., if the input continues at the intermediate level voltage, the CMOS may latch up. There is a disadvantage in that a phenomenon occurs in which there is a risk of damage. That is, there is a drawback that malfunctions and circuit damage occur.

[0005]

SUMMARY OF THE INVENTION The present invention eliminates the disadvantages of malfunctions and circuit damage as described above, and provides an image forming apparatus that can prevent malfunctions and protect the circuits. The purpose is to

[0006]

[Means for Solving the Problems] An image forming apparatus of the present invention includes an image forming means for forming an image, and a supply means detachably provided on the image forming means for supplying an image forming medium to the image forming means. and a moving means for moving the image forming medium stored in the supplying means, and a detection means for detecting that the image forming medium has been moved to a position where it can be supplied by the moving means. When the image forming means starts forming an image on the image forming medium from the supplying means, the moving means is moved until the detecting means detects that the image forming medium has been moved to a position where the image forming medium can be supplied; A processing means is provided for moving the image forming medium by the moving means to a position away from the detection position of the detecting means when image formation is completed.

[0007]

[Operation] The present invention has the above-described structure, and comprises an image forming means for forming an image, and a supply means detachably provided to the image forming means and supplying an image forming medium to the image forming means. In the above-mentioned supply means, the supply means is provided with a moving means for moving the image forming medium stored in the supply means, and a detecting means for detecting that the image forming medium has been moved to a position where the image forming medium can be supplied by the moving means. , when the image forming means starts forming an image on the image forming medium from the supplying means, the moving means is moved until the detecting means detects that the image forming medium has been moved to a position where the image forming medium can be supplied; When the image formation is completed, the moving means moves the image forming medium to a position away from the detection position of the detecting means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the internal configuration of a copying machine 1 as an image forming apparatus of the present invention, in which a photosensitive drum (image carrier) 12 is rotatably provided approximately at the center of the main body 11. ing. Around the photosensitive drum 12, a charger 13 and an exposure section 1 are arranged sequentially along the rotation direction of the photosensitive drum 12.
4, developing devices 15 and 16, a transfer charger 17, a peeling charger 18, a cleaner 19, and a static eliminator 20 are provided.

Further, an exposure system 2 is installed in the upper part of the main body 11.
1 is provided. This exposure system 21 includes an exposure lamp 22
, first to third reflecting mirrors 23, 24, 25, variable magnification lens block 26, fourth to sixth reflecting mirrors 27,
28 and 29.

The main body 11 is placed on a desk 51 so as to be separable, and inside the desk 51 there are:
Paper feed cassettes 30 and 31 are provided so as to be freely accessible from the front side.

[0012] Also, on one side of the main body 11, 1000
A large-capacity paper feeder (LCF) 52 is provided, and a manual paper feeder 53 is provided on the upper surface of the large-capacity paper feeder 52. By setting the most frequently used paper (for example, A4 size) P in the large capacity paper feeder (LCF) 52, the number of times paper runs out can be reduced.

The large capacity paper feeding device 52 has an upper cover 52.
This upper cover 52a also serves as a guide for the manual paper feed section 53. Furthermore, the large capacity paper feeder 52
includes a paper feed roller 52b and a separation roller 52c, and these paper feed roller 52b and separation roller 52c also serve as the paper feed roller and separation roller of the manual paper feed section 53.

[0014] The large capacity paper feeding device 52 is provided with the paper P.
an elevator mechanism (not shown) that moves the tray 61 up and down, a tray motor 62 that moves the tray 61 up and down by driving the elevator mechanism, and a paper feed motor that rotates the paper feed roller 52b. 63
, a lower detector 64 for detecting that the tray 61 is located at a lower position as an initial position;
A height detector 65 detects whether the height of the upper end of the upper paper P is at a predetermined position, and a notch (not shown) in the tray 61 detects whether the paper P is placed on the tray 61. A paper detector 66 is provided that detects the paper using the paper.

The height detector 65 is connected to the paper feed roller 5.
It outputs a detection signal according to the position of an actuator (not shown) that moves in conjunction with the vertical movement of 2b, and is composed of, for example, a photointerrupter and a Schmitt trigger circuit. Thereby, the height detector 65 outputs only either a high level signal or a low level signal.

The paper P fed from the paper feed cassettes 30 and 31, the large capacity paper feeder (LCF) 52, or the manual paper feed section 53 is transported along the paper transport path 32 provided in the main body 11. It is designed to be transported by

In the paper transport path 32, a registration roller 33, the transfer/separation chargers 17 and 18, a transport belt 34, a fixing device 35, and a pair of paper discharge rollers 36 are disposed in sequence along the transport direction of the paper P. ing.

[0018] Further, a document placing table 38 is provided on the upper surface of the main body 11, and a document feeding section 39 is provided on the document placing table 38. The document feeding section 39 includes a take-out section 41 that takes out the documents one by one from the document tray 40, and a take-out section 41 that transports the documents from the take-out section 41 and places them on the document placing table 38. It is composed of a conveyance section 43 that discharges the placed original onto a discharge tray 42. A detector 44 is provided within the take-out section 41 to detect whether or not a document is set on the document tray 40 .

On the other hand, a sorter device 45 is integrally incorporated in the paper discharge section of the main body 11. This sorter device 45
is a plurality of bins 4 arranged at predetermined intervals in the vertical direction.
6... and a gate means 47 provided between these bins 46... and the pair of paper discharge rollers 36. The gate means 47 includes a telescopic and rotatable guide body 48, and a pair of discharge rollers 49 is provided at the rotary end of the guide body 48.

Further, a reversing tray 54, which together with the gate means 47 constitutes a continuous reversing means 53, is provided below the bins 46. On the reversing tray 54, a reversing roller 55 that can move up and down and rotate forward and backward, and a rotatable switching gate 56 are provided.Furthermore, below the pair of ejection rollers 49, an idle roller 57 as a feed roller is provided. is provided.

When the gate means 47 is moved to the lowest stage, a pair of discharge rollers 49 are placed on the idle roller 57 and are also used as paper discharge rollers of the stacker 58, so that the paper P is directly transferred to the stacker 58. It is now being sent.

[0022] During normal copying, the exposure system 21 scans light onto the original placed on the original platen 38, and the reflected light is directed onto the photosensitive drum 12 whose surface is charged by the charger 13. is imaged to form an electrostatic latent image. This electrostatic latent image is visualized by supplying developer from the developing device 15 or 16. At this time, the paper P is supplied from the paper feed cassettes 30 and 31, the large-capacity paper feed device 52, or the manual paper feed section 53.
The paper P is sent to the image transfer section 12a between the photoconductor drum 12 and the transfer charger 17, and the developed image on the photoconductor drum 12 is transferred to the paper P. Paper P on which this image was transferred
Due to the action of the peeling charger 18, the photosensitive drum 12
The image is peeled off from the paper and sent to a fixing device 35 by a conveyor belt 34, where the image is fixed. Paper P on which this image is fixed
is discharged via the paper feed roller 36 and is discharged onto the topmost bin 46 via the gate means 47 of the sorter device 45.

Further, when a plurality of copies of the original are to be sorted, the gate means 47 is rotated in the vertical direction, and the copies are selectively sent to each bin 46 via the ejection roller pair 49 for sorting. It turns out.

In addition, in the case of double-sided copying, the gate means 47 is rotated to the lowest end so that the lower side of the ejection roller pair 49 comes into contact with the idle roller 57, and the reversing roller 55 and the switching gate 56 are moved upward. The image-fixed paper P, which is moved and sent from the fixing device 35, is sent onto the reversing tray 54 via a pair of discharge rollers 49. Next, the reversing roller 55 is lowered while being reversely rotated and comes into contact with the paper P, and when the rear end of the paper P comes off the paper ejection roller pair 36, the reversing roller 55 is stopped and the gate 56 is rotated downward. Then, at the end of the rotation, the paper P is thrown downward. Then, the reversing roller 55 is rotated in the reverse direction, and the paper P is sent between the ejection roller pair 49 and the idle roller 57 and is conveyed while being nipped. When the paper P is pinched and conveyed in this manner, the switching gate 56 and the reversing roller 55 are raised. At this time, the next sheet P is sent to the ejection roller pair 49, and is sent onto the reversing tray 54 in a state overlapping with the previous sheet P. The paper P ahead is ejected by pair 4 of ejection rollers.
9 and the idle roller 57, the paper is pinched and conveyed and directly introduced into the stacker 58. Next, the main parts of the control circuit of the copying machine 1 will be explained with reference to FIG.

That is, the copying machine 1 is provided with a main control section 71 that controls the entire copying machine 1. This main control section 71 includes a CPU 72 for control, each of the above-mentioned detectors 64 and 65
CMOS (complementary metal oxide semiconductor) 73 as an interface circuit for accepting detection signals from , 66, and C
It is constituted by a shift register 74 for converting the control signal from the PU 72 from serial data to parallel data and outputting the same. The main control section 71 includes an operation panel 75 for inputting various copying conditions, a copying section 76 for copying an image of a document, a memory 77 for storing a control program, and a motor driver 78 for driving the paper feed motor 63. , a motor driver 79 that drives the tray motor 62, a motor driver 81 that drives another motor 80,
The lower detector 64, height detector 65, and paper detector 66 are connected.

Next, the operation of the large-capacity paper feeder in such a configuration will be explained with reference to the flowchart shown in FIG. For example, when the power is turned on, the CPU 72 controls the motor driver 79 to drive the tray motor 62 to raise the tray 61. When a detection signal (ON signal) is supplied from the height detector 65, the CPU
72 controls the motor driver 79 and the tray motor 62
Start applying the brakes.

[0027] Then, when the paper detection signal is supplied by the paper detector 66, the CPU 72
During this time, the brake is applied to the tray motor 62. Then, C
The PU 72 controls the motor driver 79 and drives the tray motor 62 to lower the tray 61. When the detection signal (on signal) is no longer supplied from the height detector 65, the CPU 72 controls the motor driver 79 to turn off the tray motor 62 and put it in a standby state.

At this time, the actuator for detection is set at a position away from the height detector 65, and the CMOS 73
It is possible to prevent malfunction of the CMOS 73 and protect the CMOS 73 from damage.

When paper feeding from the large-capacity paper feeding device 52 is selected on the operation panel 75, the CPU 72 controls the motor driver 79 to drive the tray motor 62, thereby raising the tray 61. Then, when a detection signal (on signal) is supplied from the height detector 65, the CPU 72 controls the motor driver 79, applies a brake to the tray motor 62, and stops the tray 61. As a result, the topmost sheet P on the tray 61 is ready for feeding. Then, when all the copies using the paper P in the large-capacity paper feeder 52 are completed, the CPU 72 again lowers the tray 61 to the standby position.

Further, when paper is detected by the paper detector 66 and no paper is detected, the CPU 72 applies a brake to the tray motor 62 for an additional 50 ms. Next, the CPU 72 controls the motor driver 79 to drive the tray motor 62 so that the tray 61
lower. When a detection signal (on signal) is supplied from the lower detector 64, the CPU 72 controls the motor driver 79 to turn off the tray motor 62, and a guide means (not shown) issues a service call to indicate that there is no paper.

[0031] Also, after the tray 61 starts to rise, 1
If a detection signal is not obtained from the height detector 65 even after 0 seconds or more has elapsed, a service call is made to report an error by a guide means (not shown).

Furthermore, after the tray 61 starts descending,
If a detection signal is not obtained from the lower detector 64 even after 0 seconds or more has elapsed, a service call is made to report an error by a guide means (not shown).

Furthermore, after the tray 61 starts descending,
If the detection signal from the height detector 65 does not turn off even after 0 seconds or more has elapsed, a service call is made to report an error by a guide means (not shown).

As mentioned above, when the paper in the large-capacity paper feeder is on standby when the paper is not being used, the tray on which the paper is placed in the large-capacity paper feeder is stopped in a slightly lowered state, and the height of the paper is adjusted. The actuator, which serves as a detection object in a height detector that performs detection, is evacuated.

[0035] This allows the CMO used on the input side to
The voltage level (intermediate level) in the area that is not guaranteed by the S threshold level will certainly not enter, which will eliminate CMOS malfunctions, and will also prevent the input from continuing at the intermediate level voltage due to assembly errors, etc. teC
It is also possible to avoid the risk of MOS latch-up and damage.

Furthermore, since the paper is away from the paper feed roller when the power is turned off, even if the paper feed roller is rotated by the pull-up data of the shift register when the power is turned on, the paper will not be moved.

[0037]

[Effects of the Invention] As detailed above, according to the present invention,
An image forming apparatus that can prevent malfunctions and protect circuits can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a copying machine in an embodiment of the present invention.

FIG. 2 is a sectional view showing the internal configuration of the copying machine in the embodiment of FIG. 1;

FIG. 3 is a flowchart for explaining the operation of the large-capacity paper feeder in the embodiment of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Copying machine, 52... Large capacity paper feeder, 52b... Paper feed roller, 61... Tray, 62... Tray motor, 63... Paper feed motor, 64... Lower side detector, 65... Height detector, 66... paper detector, 71...main control unit, 72...CPU, 73...CM
OS, 74...Shift register.

Claims (1)

[Claims] 1. An image forming apparatus comprising an image forming means for forming an image, and a supply means detachably provided to the image forming means for supplying an image forming medium to the image forming means, the supply means having a , a moving means for moving the image forming medium stored in the supplying means, a detection means for detecting that the image forming medium has been moved to a position where it can be supplied by the moving means, and the supplying means by the image forming means. When starting image formation on the image forming medium, the moving means is moved until the detecting means detects that the image forming medium has moved to a position where the image forming medium can be supplied, and when the image forming is finished, the detecting means detects An image forming apparatus comprising: processing means for moving the image forming medium by the moving means to a position deviated from the image forming apparatus.