JPS63112368A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of an inferior stock by providing a paper- height detecting means for detecting the height of a bundle of sheets of paper which are discharged. CONSTITUTION:When the height of a bundle of sheets of paper P discharged onto a discharged paper stacker 19 reached a defined height, a filler 22 and a light shielding board 23 are pushed by the sheets of paper P and swung from the broken line positions to the solid line positions, the light shielding board 23 comes off of the inside of a paper height sensor 24, and a full stop signal is sent out of the sensor 24. Thereby, printing can be stopped and a paper discharging passage can be switched over, preventing an inferior stock. Further, printing conditions at the time of stopping printing, i.e., information on date and hour information, host number information, handled number of sheets information, printed number of sheets information, etc. can be printed to notify an operator of the conditions on a printing stopping condition, to prevent confusion. Thereby, the interval of time for feeding sheets of paper can be made longer improving an operating property.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an image forming apparatus that discharges paper on which an image has been formed via a reversing mechanism.

BACKGROUND OF THE INVENTION Generally, some image forming apparatuses such as laser printers and copying machines are equipped with a paper discharge unit having a reversing mechanism for discharging paper on which an image is formed face-down so as to form pages.

In such an image forming apparatus, it is desired that the number of sheets of paper that can be loaded into the paper feed tray etc. can also be stocked in the paper ejection stacker. In particular, when using thick paper such as bond paper or rag paper, the paper stocked in the paper output stacker may become thicker due to the paper being warped or containing heat after the fixing process depending on the quality of the paper. The number of sheets of paper that can be fed from the paper device cannot be stocked.

In this case, if the height of the paper stocked in the paper ejection stacker becomes high, the stacked paper may come into contact with the ejection roller etc. and prevent the paper from being ejected, or the paper being ejected may push out the stocked paper. There is an inconvenience that stock defects such as out of order occur.

This invention was made in view of the above points, and aims to prevent stock defects.

Structure In order to achieve the above object, the present invention is provided with a paper height detection means for detecting the height of a stack of ejected paper sheets.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 1 is a schematic configuration diagram showing an example of a laser printer as an image forming apparatus embodying the present invention.

This laser printer has a main driving roller 1 and a driven roller 2.
A photoreceptor belt 3 stretched between the photoreceptor belts 3 rotates in the direction of the arrow when printing starts, and the surface of the photoreceptor belt 3 is uniformly charged by a charging device consisting of a charger 4 and a grid 5.

Then, the optical writing device 6 emits a laser beam corresponding to the written image onto the photoreceptor belt 3 to form an electrostatic latent image corresponding to the written image, and the developing device 7 emits a laser beam corresponding to the written image onto the photoreceptor belt 3. Toner is applied to the image to visualize it.

Then, the uppermost sheet P of the sheets P loaded in the sheet feed tray 8 is taken out by the sheet feed roller 9 and sent to the registration rollers 10, and the registration rollers 10 are driven to rotate at a predetermined timing to separate the sheets. The toner image on the photoreceptor belt 3 is transferred onto a sheet of paper by applying a predetermined voltage to the transfer charger 11 at a predetermined timing.

After that, the charge remaining on the photoreceptor belt 3 is removed by the static eliminator 1.
2, and the toner remaining on the photoreceptor belt 3 is removed by the cleaning device 13 in preparation for the next image forming process.

On the other hand, the paper on which the toner image has been transferred is separated from the photoreceptor belt 3 by corner separation, sent to the fixing device 1B by the conveying device 15, and after being subjected to heat fixing processing in the fixing device 1B, is reversed by the reversing mechanism 17. The paper is ejected from the ejection roller pair 18 onto the ejection stacker 19.

FIG. 2 is a block diagram showing details of the paper discharge section of this image forming apparatus.

Below the discharge roller 18 of this paper discharge section, a fish 22 facing the paper discharge stacker 19 via a rotating shaft 21 and a light shielding plate 23 integrally formed with the fish 22 are swingably disposed. When the height of the bundle of sheets P stocked on the sheet discharge stacker 1 on the first day is lower than a predetermined height, this fisher 22 is in the position shown by the broken line, and the sheet P on the sheet discharge stacker 19 is in the position shown by the broken line.
When it reaches a predetermined height or more, the front side is pushed by the paper P and swings to the position shown by the solid line. In addition, the light shielding plate 23i
The fin 22 moves simultaneously and swings from the position shown by the broken line to the position shown by the solid line.

A paper height sensor 24 is provided which is a transmission type photosensor consisting of a light emitting element and a light receiving element that face each other with the light shielding plate 2ES in between. This paper height sensor 2
4, when the light shielding plate 23 is in the position shown by the broken line, the light emitted from the light emitting element is blocked and does not enter the light receiving element, but when the light shielding plate 23 is in the position shown by the solid line, the light emitted from the light emitting element is received. Since the light is input to the element, it is possible to detect whether or not the paper P on the top of the paper stacker has reached a predetermined height based on the output of the paper height sensor 24.

FIG. 3 is a schematic configuration diagram showing details of the paper ejection path switching section of this image forming apparatus.

A paper path switching lever 25 (91) is disposed at the front stage of the paper ejection path from the fixing device 16 to the reversing mechanism 17 so as to be swingable on a support shaft 26. This paper ejection path switching lever 25 is swung between the position shown by the solid line and the position shown by the broken line by a solenoid (not shown). At this position, the conveyance path to the reversing mechanism 17 is blocked and the paper ejection path is switched to the paper ejection port 27 side. A paper discharge tray 28 is removably attached to the paper discharge port 27 as appropriate.

FIG. 4 is a block diagram showing the control section of this image forming apparatus.

The controller 31 receives data such as character codes, control codes, and control commands sent from a host such as a word processor, data processor, workstation, personal computer, and image editing processing device, and sends it to the engine controller 32. It performs processing such as receiving data from the controller 32, and also receives data from the engine controller 32 from the paper output stacker 1.
When full stock information indicating that the height of the stack of sheets stored on the paper stack 9 has reached a predetermined height is received, the optical writing device r! 16 etc. to print the print condition information at that time.

The engine controller 32 is set to CPt5. ROMES4
．． A microcomputer system consisting of RAM 3; It displays various information on the third day, and also controls the printing stop based on the detection signal from the paper height sensor 24 and controls the drive of the solenoid 39 that drives the paper ejection path switching lever 26. Send write information.

The optical control circuit 41 performs on/off control of a semiconductor laser such as a laser diode of the optical writing device 6 based on the received write information, and performs controls such as modulating the laser beam according to the written image.

Next, the operation of this embodiment configured as described above will be explained with reference to FIGS. 5 and 6.

First, the engine controller 32 controls the optical writing device 6 and various parts related to image formation according to image information sent from the controller 31 to execute an image forming process and print the image from the host onto the paper P. Process. At this time, #i: Mini paper path switching lever 2 is in the position shown by the solid line in FIG. They are stocked face down sequentially on the first day.

In this case, the fence 22 and the light shielding plate 23 are in the position shown by the broken line until the height of the bundle of paper P stored above the paper discharge stacker reaches a predetermined height. The paper height sensor 24 outputs a not full signal, which is a signal indicating that the height of the stack of paper P stored above the paper output stacker is lower than a predetermined height. Engine controller 32
is input.

As a result, the engine controller 32 continues to execute one image forming process while the not-full signal is input from the paper height sensor 24, and the paper sheets P on which images are formed are sequentially stocked on the paper discharge stacker 1st. To go.

When the height of the bundle of sheets P stocked in the sheet discharge stacker 19 reaches a predetermined height, the fibers 22 and the light shielding plate 23 are pushed by the sheets P and move from the position shown by the broken line to the position shown by the solid line. By swinging, the light shielding plate 23 detects the paper height sensor 24.
Since the paper is removed from the inside, the paper height sensor 24 indicates that the height of the stack of paper P stored on the paper discharge stacker 19 has reached a predetermined height, that is, the paper is in a full stock state. A full stock signal, which is a signal, is input to the engine controller 32.

Therefore, upon receiving the full stock signal from the paper height sensor 24, the engine controller 32 starts executing the engine controller full stock process shown in FIG. 5, and first performs the paper feeding operation for the next print. After stopping, full stock information is sent to the controller 31, and the display panel 38 displays that the full stock state has been reached.

On the other hand, when the controller 31 receives the full stock information from the engine controller 32, it starts executing the controller full stock process shown in FIG. Sends status information indicating. Then, the engine controller 32 prints out the print conditions when the print is stopped when the stock is fully stocked.
Directly controls the optical control circuit 41 of the printer to control the optical writing device 6 according to the image data of the print conditions, and also instructs the engine controller 52 to print the print conditions.
Execute control of the image forming process by pu33,
Print the print conditions.

Here, the printing conditions include, for example, date and time information (for example, 1986.10.30 2:30
:15 p, m), host number, information, processed number information (number of sheets to be printed), printed number information (number of sheets already printed), etc. are printed. As a result, even when printing is stopped due to full stock, it is easy to know in which state printing stopped, and confusion does not occur.

Note that the date and time information may include a built-in clock inside the controller 31, or may be received from the host side. This information is received from the host side from information on the number of sheets to be processed, and information on the number of sheets to be printed can be obtained from a counter that counts up each time one sheet is printed.

Thereafter, the controller 31 enters a print restart standby state and determines whether or not it has received a face-up paper ejection instruction from the host side, and when it receives a face-up instruction, it can perform face-up paper ejection (if the paper ejection tray 28 is installed). If face-up sheet ejection is possible, the engine controller 32 is instructed to perform face-up sheet ejection, and then print restart processing is performed.

The engine controller 32, which receives the face-up paper discharge instruction from the controller 31, drives the solenoid 39 to swing the paper discharge path switching lever 25 from the position shown by the solid line to the position shown by the broken line.

As a result, the paper printed in the resumed printing process is ejected to the paper ejection tray 28 face-up (in reverse order).

Note that here, the host side instructs face-up paper ejection, but it is also possible to always switch to face-up paper ejection when the paper ejection tray 28 is installed, or to instruct the printer side to eject face-up paper. A switch may be provided to switch between down-discharge and face-up discharging, and the switch may be operated to shift to face-up discharging.

On the other hand, when the paper does not shift to face-up paper ejection, the engine controller 32 checks whether the paper height sensor 24 is turned off and removes the paper that is in the full stock state from the paper ejection stacker 19. When the paper is removed from the paper discharge stacker 19, the controller 31 sends not-full information to the controller 31. When the controller 31 receives this knot-full information, the controller 31 performs printing restart processing and resumes printing. Continue.

In this way, this image forming apparatus is equipped with a paper height detection means that detects the height of the paper ejected to the paper ejection stacker, so it is possible to stop printing or switch the paper ejection path depending on the detection result. This makes it possible to prevent stock defects, and by printing the printing conditions when printing is stopped, it is possible to notify the operator of the conditions under which printing is stopped, thereby preventing confusion.

As a result, compared to a case where the number of sheets that can be loaded into the paper feeder is reduced to prevent the discharged paper stocker from becoming full, the time interval between paper replenishments can be lengthened and operability is improved. Furthermore, when using thick paper, it is possible to align the pages, which improves operability, compared to a case where the paper is always ejected face-up and page alignment is not possible.

As explained above, according to the present invention, stock defects can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus embodying the present invention, FIGS. 2 and 3 are schematic configuration diagrams showing details of the paper discharge section and paper discharge path switching section, and FIG. 4 5 is a block diagram showing the control section, FIG. 5 is a flow diagram showing an example of full stock processing executed by the control section, and FIG. 6 is an explanatory diagram for explaining the same in detail. 3... Photoreceptor belt 6... Optical writing device 8...
・Paper feed tray 17... Reversing mechanism 18... Ejection roller pair 1st... Paper ejection stacker 21... Rotating shaft
22... Fisi 23... Light shielding plate 24
... Paper height sensor 25 ... Paper discharge path switching lever 31 ... Controller 32 ... Engine controller Fig. 1 Fig. 2 Fig. 3 Fig. 6

Claims (1)

[Claims] 1. An image forming apparatus that discharges sheets on which an image has been formed via a reversing mechanism, the image forming apparatus comprising a sheet height detection means for detecting the height of a bundle of sheets that has been discharged.