JPH05208752A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device, which uses not only a paper sheet having a routine size lower than the maximum size but also a long paper sheet longer than the paper sheet, at a low cost. CONSTITUTION:The control panel 5 of an LB printer 1 is provided with a mode assigning SW 35 for indicating whether a paper sheet is a routine size paper sheet or a long paper sheet and a ten key SW 36 for inputting the length of the long paper sheet where occasion demands. When a routine size mode is assigned, printing is made on a paper sheet having a routine size as usual. When a long sheet mode is assigned, even when the length of the paper sheet is longer than the maximum size of the printer, printing is carried out without stopping in the middle owing to an excessively long sheet error. By inputting the length of the long paper sheet by means of the ten key SW 36, processing of an error is effected according to the inputted length when a feed conveyance error occurs during printing.

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 using an electrophotographic process, and more particularly to a sheet conveying device of the image forming apparatus.

[0002]

2. Description of the Related Art Image forming apparatuses for forming an image on plain paper using an electrophotographic process include copying machines such as electronic copying machines, digital copying machines and color copying machines, LB (laser beam) printers and LEDs. (Light emitting diode) printer, optical printer such as LCDA (liquid crystal array) printer,
Alternatively, there is a high-speed facsimile or the like incorporating these optical printers.

The sheets used in these image forming apparatuses are standard sizes of A size or B size series, especially A3 among them.
Paper of B4, A4, B5 size is often used. Therefore, except for special cases such as industrial copying machines, most of the office machines are image forming apparatuses of maximum size A3 or B4, and there are also those of maximum size A4 for household use. ..

In general, such an image forming apparatus can selectively use a sheet having a maximum size or less, so that there is no problem in almost all cases. In the case of a copying machine, if the original is a standard size, it can be enlarged or reduced in addition to normal size without any waste. Even if the original is an irregular size, a blank is added to the standard size paper. It was possible to make a copy and trim the margins if necessary.

[0005]

However, even if the width of the sheet orthogonal to the conveying direction is equal to or smaller than the maximum size, when the sheet whose length matching the conveying direction exceeds the maximum size is used, the information detecting means is Since the length information out of the detected information is exceeded, the error detection means outputs an error signal, and the conveyance control means stops the sheet conveyance means.

Below, when necessary, the size of the paper (width ×
For example, in the case of a copying machine having a maximum size of A3 size (297 × 420), which is out of the standard size, it is a standard size in the United States (double letter size (279 × 4)).
When the document 32) is copied onto a sheet of the same size, the width of the sheet is smaller than the maximum width of the copying machine so that it can be passed, and in general, the document has a margin so that it should be sufficiently copied. However, since the length exceeds the maximum length by 12 mm, it is determined that there is an error in feeding two sheets of A3 size paper with a deviation, the sheet conveyance is stopped midway, and copying cannot be performed.

Further, for example, in the case of a printer connected to a computer which is a host machine, it is often impossible to predict the amount of data to be output, especially by technical calculation, and even if it can be empirically predicted, if the maximum length is a little longer, then 1 Although it is possible to print on one sheet, it often happens that the job is divided into two sheets on the way.

As described above, there is a demand for using a paper that is slightly longer than the maximum length of the paper, or a roll paper or a perforated format paper (hereinafter collectively referred to as a "long sheet") in relation to the United States. There were many schools and research institutes.

The present invention has been made in view of the above points, and an object thereof is to provide at low cost an image forming apparatus which can use not only fixed-size sheets of the maximum size or smaller but also long sheets. And

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a sheet conveying means, an information detecting means for detecting various kinds of information generated during sheet conveyance by the sheet conveying means, and an information detecting means. An error detection unit that outputs an error signal in the event of an abnormality in accordance with the information detected by the unit and the size of the sheet used, and a sheet conveyance unit according to the error signal output by the error detection unit and the information detected by the information detection unit In the image forming apparatus for forming an image on a sheet by an electrophotographic process, a conveyance control unit for controlling the sheet size of a fixed size mode using a fixed size sheet and a long sheet mode using a long sheet. A mode designating means for selectively designating any one and a mode switching for switching the function of the error detecting means according to the mode designated by the mode designating means. It is provided with a and the stage.

The mode switching means may be means for invalidating all the detection results of the error detecting means when the long sheet mode is designated by the mode designating means. Alternatively, the mode switching unit may be a unit that invalidates only the detection result regarding the length of the sheet by the error detection unit when the long sheet mode is designated by the mode designation unit.

Further, when the long sheet mode is designated by the sheet length input means for inputting the length of the long sheet to be used and the mode designating means, the length of the long sheet inputted from the sheet length input means. And means for controlling the function of the error detecting means in accordance with the above.

[0013]

In the image forming apparatus constructed as described above, when the standard size mode is designated by the mode designating means, the mode switching means controls the error detecting means to operate with the conventional function. Form an image on paper. When the long sheet mode is designated, the mode switching means controls so that the error detection means does not output an error signal that interferes with the processing of the long sheet.
The image forming apparatus forms an image on a long sheet.

When the long sheet mode is designated by the mode designating means, if the mode switching means invalidates all the detection results of the error detecting means, no error signal is output, so that the image forming apparatus is long. Form an image on the sheet. Alternatively, if the mode switching means is means for invalidating only the detection result regarding the length of the paper by the error detection means, other error signals are output, so that the image forming apparatus outputs an image of good quality on a long sheet. To form.

Further, a sheet length input means is provided, and when the long sheet mode is designated by the mode designating means and the length of the long sheet is inputted by the sheet length input means,
The mode switching means switches the function of the error detection means, and the means for controlling the function controls the function of the error detection means according to the input length of the long sheet to detect the abnormal length of the long sheet. Since the error signal is output even when it is detected, the image forming apparatus surely forms an image of good quality on the long sheet.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 shows an L according to an embodiment of the present invention.
It is a schematic block diagram which shows the internal mechanism of a B (laser beam) printer.

In this LB printer, of the upper and lower two sheet feeding devices, in the normal case where standard size sheets are used, from the sheet stack 11a on the sheet feeding cassette 10 which can be replaced according to the size of the lower stage to the lower stage. The sheet 11 is fed by the sheet feeding roller 12a of the photosensitive drum 1 and the sheet 11 is timed by the pair of registration rollers 13
5 is conveyed to the transfer position.

The surface of the photosensitive drum 15, which is rotationally driven in the direction of the arrow by the main motor 14, is charged by the charging charger 16, and is scanned by the modulated spot from the optical writing unit 25 to electrostatically charge the surface. A latent image is formed. The developing unit 17 attaches toner to the latent image to make it visible.

The toner image is transferred by the transfer charger 18 onto the sheet 11 conveyed by the registration roller pair 13, the sheet 11 on which the toner image is transferred is separated from the photosensitive drum 15, and fixed by the conveying belt 19. It is sent to the unit 20, and is pressed against the fixing roller 20b by the pressure roller 20a, and is fixed by the pressure and the temperature of the fixing roller 20b which is heated in advance.
The paper 11 that has left the fixing unit 20 is discharged by a paper discharge roller 21 to a paper discharge tray 22 provided on the side surface of the printer.

The toner remaining on the photosensitive drum 15 is removed and collected by the cleaning unit 23. A printed circuit board (PCB) 24, which constitutes a controller and an engine driver, is mounted above the printer.

When the operator designates the long sheet mode by the mode designation means (not shown), the long sheets 27 are set one by one on the upper sheet feeding device, that is, the manual feed tray 26. The LB printer has an upper paper feed roller 12
The long sheet 28 is fed by b. Images are printed on the subsequent long sheets 28 in the same manner as the paper 11,
The paper is discharged to the paper discharge tray 22.

A registration sensor 28 and a paper discharge sensor 29 are provided immediately after the registration roller pair 13 and the paper discharge roller 21, respectively. Registration sensor 28 and paper discharge sensor 2 which constitute information detection means for detecting various information
9 detects the sheet 11 or the long sheet 27 passing therethrough, and detects the timing of passage of the leading end and the trailing end thereof. From such information, it is possible to know the length of the paper 11 or the long sheet 27, the timing of sending out for transferring the toner image, the transportation status, and whether the discharge is completed safely.

FIG. 1 is a block diagram showing an example of a control system of the LB printer shown in FIG. The LB printer 1
A controller 2 that controls the entire printer and processes image data; an engine 3 that is a mechanical unit that forms an image;
The controller 2 comprises an engine driver 4 for controlling the engine 3 while communicating with the controller 2, and an operation panel 5 connected to the controller 2 for inputting operator's instructions and displaying information to the operator. The controller 2 is also an external device. It is also connected to a certain host machine 6.

The controller 2 includes a ROM, which is a storage unit,
Microcomputer with built-in RAM (hereinafter referred to as "CP
U ”) 7 in response to an operator's instruction input from the operation panel 5 and a command from the host machine 6.
RA for controlling the LB printer 1 as a whole and for developing image data input from the host machine 6 into a bitmap and incorporating it
It is stored in M and output to the engine driver 4 as a video signal. Further, the operator's instruction content, error information input from the engine driver 4, and the like are output to the operation panel 5 and displayed.

The engine 3 is roughly classified into a process control unit 3
1, a sequence mechanism unit 32, and a sensor group 33 including various sensors. The process control unit 31
Charge control such as charging, transfer and charge removal, voltage control such as developing bias, optical output control of the optical writing unit 25, temperature control of the fixing roller 20b, rotation speed control of the main motor 14 and the like (not shown) are performed. It consists of equipment groups.

The sequence mechanism section 32 is mainly composed of a motor such as the main motor 14 constituting the sheet conveying means, a clutch, a solenoid and the like, which carries out an on / off operation in accordance with an instructed timing. A writing unit 25 is also included. Sensor group 3 as information detection means
3 is the registration sensor 28 and the paper discharge sensor 2 shown in FIG.
In addition to 9, a voltage sensor, an optical sensor, a temperature sensor, a rotation sensor, and the like are provided, and the information of each part of the engine 3 is detected and output to the engine driver 4.

Like the controller 2, the engine driver 4 comprises a CPU 8 having a built-in ROM and RAM,
The CPU 8 which is an error detection unit and a conveyance control unit sets a target value for process control in the process control unit 31 in accordance with a command from the controller 2 and information from the sensor group 33, and sets it in the sequence mechanism unit 32. Outputs an on / off signal and a timing signal for starting and stopping the operation to control the engine 3, and when the information from the sensor group 33 exceeds a preset limit value, it is determined as an error and an error signal is output. It outputs and displays, and depending on the content of the error, it carries out processing such as emergency stop.

Further, the CPU 8 is the CP of the controller 2.
A timing signal and a clock are output to U7, and a video signal input in synchronization with them is output to the optical writing unit 25 to write an image. Areas for counters A and B, which will be described later, are set in the RAM built in the CPU 8.

On the operation panel 5, a group of switches for inputting an operator's instruction such as a mode designating SW (switch) 35 as a mode designating means and a ten-key SW 36 as a sheet length inputting means, and an operator and a host machine 6 are inputted. The display unit 37 displays the contents of instructions, the contents of processing during operation, the contents of errors that have occurred, and the like.

When the long sheet mode is designated by the mode designation SW 35, the CPU 8 which is also a mode switching means.
Ignores the information from the sensor group 33 as a means for invalidating all the error detection results, or the registration sensor 2 as a means for invalidating only the detection result regarding the paper length.
8 or the length information obtained by the paper discharge sensor 29 is ignored, and even if the length exceeds, it is not judged as an error. Alternatively, as a means of controlling the error detection function, the numeric keypad S
The length information is determined according to the length of the long sheet designated by W36.

FIGS. 3 to 6 are flow charts showing an example of a routine of the CPU 8 in a subroutine format. FIG. 3 shows a mode selection routine, and FIGS. 4 and below show a mode processing routine jumping from the mode selection routine. Four
And FIG. 5 shows the first of the first long (sheet) processing routine A.
FIG. 6 is a flow chart showing a routine that also serves as a standard (size) processing routine and a second long processing routine B. The step number is "S"
Will be abbreviated.

When the mode selection routine shown in FIG. 3 starts, a print start command input from the host machine 6 is waited in S (step) 1, and when the print start command is input, the motor is turned on in S2, and then S3. To specify mode SW3
It is determined whether or not the instruction of 5 is the long sheet mode, and if it is the long sheet mode, the process jumps to S6. If not, that is, if it is the standard size mode, the process proceeds to S4 and the CPU 8 R
Data corresponding to the size (length) of the paper 11 is read from the table stored in the OM in advance and set in the counters A and B in the RAM. When the data set is completed, the routine jumps to the routine for routine processing in S5.

When jumping to S6 in the long sheet mode, it is judged whether or not the length of the long sheet is input from the ten-key switch 36, and if it is input, the process jumps to S8, that is, the length is not designated. If there is, it proceeds to S7 and jumps to the subroutine of the long process A. When jumping to S8, the length data of the long sheet input from the ten-key switch 36 is set in the counters A and B, and the subroutine of the long process B is jumped to in S9.

When returning from the subroutine of the mode processing jumped from any one of S5, S7 and S9, the motor is turned off in S10 to terminate the mode selection routine and return to the main routine.

The first embodiment of the long processing routine A shown in FIG. 4 in which the length is not specified relates to the information generated during the sheet conveyance of the CPU 8 (error detecting means) for judging the information from the sensor group 33. This is an example of invalidating all the detection results. Therefore, in this subroutine, the CPU 8 of the engine driver 4 forms an image on the long sheet 27 only by the control of the process control unit 31 of the engine 3 in S12, so that the long sheet 27 is discharged to the paper discharge tray 22. The engine 3 is still operating.

Therefore, the operator can use the long sheet 27.
Must be confirmed and the motor off instruction must be given from the operation panel 5, for example. That is, in S13, the motor off instruction input is awaited, and if the instruction is input, the process returns to the mode selection routine.

The second embodiment of the long processing routine A shown in FIG. 5 in which the length is not specified is an example of invalidating only the detection result regarding the length of the long sheet among the error detection results by the CPU 8. .. Therefore, the CPU 8 controls the process control unit 31 and all sequence control except the length of the sequence mechanism unit 32. In the LB printer 1, the conveyance speed of the paper 11 or the long sheet 27 (hereinafter collectively referred to as "paper") is 10 mm / sec, and the conveyance distance from the registration sensor 28 to the paper ejection sensor 29 is less than 300 mm. Is.

When jumping to the subroutine shown in FIG. 5, first in S15, it is judged whether or not the registration sensor 28 detects the paper and is turned on. If not, that is, if it is not turned on, the motor is turned on (paper is turned on) in S16. It is determined whether or not 1 second has elapsed from the start of conveyance, and if not, the process returns to S15, and if the registration sensor 28 is off, that is, if the sheet is not detected even after 1 second, it is determined that a paper feed error has occurred, and S17 Then, the process advances to step (9) to display the paper jam and returns to the mode selection routine.

If the registration sensor 28 is turned on within one second, the process proceeds to S18 to perform the process control, and in S19, the paper discharge sensor 29 detects the paper and determines whether or not it is turned on. If not, that is, if it is not turned on, S20
It is determined whether or not 10 seconds have passed since the registration sensor 28 was turned on. If NO, the process returns to S19, and if the sheet ejection sensor 29 is off even after 10 seconds have passed, it is determined that a paper conveyance error has occurred. Then, the process advances to S21 to display a paper jam and returns.

If the paper discharge sensor 29 is turned on within 10 seconds, the process waits until the paper discharge sensor 29 is turned off at S22. When the paper discharge sensor 29 is turned off, that is, the paper discharge is completed, the process returns to the mode selection routine.

The long-length processing routine A, which does not specify the length described above, allows the operator to specify the length on a continuous sheet such as roll paper or format paper when the operator finds the length to be bothersome. This is effective when there is no such item. In the first embodiment shown in FIG. 4 as well, there is no problem if a paper feeding / conveying error does not occur, but there is a problem that the operator must stop manually. On the other hand, in the second embodiment shown in FIG. 5, there is no need for manual stop, and when a feeding error occurs, a paper jam is displayed and the stop is performed.

However, even in the second embodiment, in the case of roll paper or format paper, the paper discharge sensor 29 does not turn off, so it must be stopped manually.
The problem can be solved by instructing the host machine 6 to stop after printing in advance, and the LB printer 1
After the paper has stopped, you can cut the roll paper or format paper and eject it manually.

When this subroutine is started, the fixed length processing routine B shown in FIG. 6 and the long length processing routine B which designates the length first determine in S25 whether or not the registration sensor 28 is turned on. Since the processing of S27 is exactly the same as the processing of S15 to S17 in FIG. 5, its explanation is omitted.

If the registration sensor 28 is turned on within one second after the motor is turned on, the process proceeds to S28, in which the data relating to the length of the paper is set in advance in S4 or S8 of the mode selection routine (FIG. 3). Of the counters A and B in the RAM, the counter A is started and the process proceeds to S29 to perform process control. The subsequent processing of S30 to S32 is also similar to the processing of S19 to S21 in FIG.

If the paper discharge sensor 29 is turned on within 10 seconds after the registration sensor 28 is turned on in S30, S
After proceeding to 33 to start the counter B, proceeding to S34, it is determined whether or not the registration sensor 28 is turned off, that is, whether or not the trailing edge of the sheet has passed the registration sensor 28.

No, that is, if the sheet has not passed the registration sensor 28, the contents of the counter A are judged in S35, and whether the scheduled passage time at which the sheet has finished passing after the registration sensor 28 is turned on has passed. To judge.
If the scheduled passage time has not elapsed, the process returns to S34, and if the registration sensor 28 remains on despite the scheduled passage time has elapsed, it is determined that a sheet feeding / conveying error has occurred, and the process proceeds to S36. Display the paper jam and return.

If the registration sensor 28 is turned off within the scheduled passage time, the process proceeds to S37 to determine whether the paper discharge sensor 29 is turned off.
Is determined to determine whether the scheduled passage time has passed since the paper discharge sensor 29 was turned on. This S37
And S38 are the same as S34 in the registration sensor 28.
Since it is the same as the processing of S35 and S35, detailed description thereof will be omitted.

If the sheet discharge sensor 29 is turned off within the scheduled passage time, it is judged that the sheet discharge has been safely completed, and the process returns to the mode selection routine. Even after the scheduled passage time has passed, the sheet discharge sensor 29 is turned on. If so, the flow advances to S39 to display a paper jam and return to the mode selection routine.

According to the length processing routine B, the operator inputs the length of the length sheet 27 from the ten-key switch 36 of the operation panel 5, so that the standard size sheet 1 is obtained.
Since the processing is exactly the same as that of 1, the process control and the sequence control are all performed, and no serious trouble occurs even if any error occurs.

As described above, the image forming apparatus according to the present invention includes, for example, the operation panel 5 as hardware.
Since a long sheet can be used only by providing the mode designation switch 35 or the ten-key switch 36, the cost can be slightly increased.

[0051]

As described above, according to the present invention, it is possible to provide, at a low cost, an image forming apparatus that can use not only a regular size sheet of the maximum size or less but also a long sheet.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a control system of an LB printer which is an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an internal mechanism of the LB printer shown in FIG.

3 is a flowchart showing an example of a mode selection routine by the control system shown in FIG.

4 is a flowchart showing a first embodiment of a long processing routine A jumping from the mode selection routine shown in FIG.

5 is a flowchart showing a second embodiment of a long processing routine A jumping from the mode selection routine shown in FIG.

FIG. 6 is a flowchart showing an example of a fixed form processing routine / long processing routine B that jumps from the mode selection routine shown in FIG.

[Explanation of symbols]

1 LB printer (image forming apparatus) 3 engine 4 engine driver 5 operation panel 8 CPU (microcomputer: error detection means, conveyance control means, mode switching means, means for invalidating detection results, error detection means) Means) 11 paper 27 long sheet 32 sequence mechanism section (paper conveying means) 33 sensor group (information detecting means) 35 mode designation SW (mode designation means) 36 numeric keypad SW (sheet length input means)

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 15/00 102 108 7369-2H

Claims (4)

[Claims] 1. A paper conveying means, an information detecting means for detecting various kinds of information generated while the paper is being conveyed by the paper conveying means, and the information detected by the information detecting means and the size of the paper used. An error detection unit that outputs an error signal when an abnormality occurs, and a conveyance control unit that controls the sheet conveyance unit according to the error signal output by the error detection unit and the information detected by the information detection unit. In an image forming apparatus for forming an image on the paper by a photographic process, a mode for selectively specifying one of a standard size mode using a standard size paper and a long sheet mode using a long sheet as the paper. And a mode switching means for switching the function of the error detecting means according to the mode designated by the mode designating means. That the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the mode switching means is means for invalidating all detection results of the error detecting means when the long sheet mode is designated by the mode designating means. 3. The mode switching means is means for invalidating only the detection result regarding the length of the sheet by the error detecting means when the long sheet mode is designated by the mode designating means. Image forming device. 4. The image forming apparatus according to claim 1, wherein the sheet length input means for inputting the length of the long sheet to be used, and the sheet length when the long sheet mode is designated by the mode designating means. An image forming apparatus comprising: means for controlling the function of the error detecting means according to the length of the long sheet input from the input means.