JPH0459543A - Picture forming device - Google Patents

Abstract

PURPOSE:To reduce the number of counters and to reduce the burden of a control part by storing the content of each processing related to formation of a picture and clocking information related to execution of each processing and orderly executing corresponding processing by referring to clocking information outputted from a clocking information output means. CONSTITUTION:The content of a plurality of kinds of processing related to formation of a picture and time information related to execution of processing effected in correspondence to the content of each processing related to formation of the picture are stored in a memory means 743, for example, in formation of a table. Time information outputted from a time information output means is compared with time information stored in the memory means 743, and when the two kinds of information coincide with each other, processing, corresponding to time information, of processing stored in the memory means 743 is orderly executed. This constitution reduces the number of counters and relieves the burden of a control part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus used in laser beam printers, copying machines, and the like.

(Prior Art) Laser beam printers, copying machines, and the like have a paper feeding device for feeding sheets of paper, which are media on which images are formed, one by one. A sheet of paper fed from this paper feeding device is conveyed along a conveyance path, and an image is formed in an image forming section. The paper on which this image has been formed is conveyed along a conveyance path and is discharged to a discharge section.

When a conventional image forming apparatus receives a conveyance start command, it operates a dedicated counter, and refers to the count value of this counter to execute various processes related to image formation, such as processes related to sheet conveyance. Further, in such an image forming apparatus, it is necessary to detect an abnormality in the conveyance of the paper conveyed through the conveyance path, that is, a jam.

A conventional image forming apparatus has a timer for detecting a jam and a detection switch for detecting paper, and after a predetermined time set by the timer has elapsed, performs a dedicated process related to jam detection by referring to the state of the detection switch. Try to run it and determine if a jam is occurring.

(Problem to be Solved by the Invention) However, conventional image forming apparatuses must execute a dedicated jam detection process in order to determine the state of paper conveyance, and furthermore, a simple method is used to detect jams. An image forming apparatus that can perform detection has been desired.

In addition, conventional image forming apparatuses must prepare a counter for each sheet of paper on which an image is to be formed, and when forming multiple types of images on multiple sheets of paper, the number of counters corresponding to the number of sheets of paper must be prepared. However, the burden on the control unit including a CPU and the like is heavy.

The present invention has been made in view of the above-mentioned problems, and it is possible to easily and reliably perform jam detection, etc. without executing a dedicated process related to jam detection, and by reducing the burden on the control unit consisting of a CPU, etc. as much as possible. An object of the present invention is to provide an image forming apparatus that can perform processing related to the formation of images.

[Structure of the invention]

(Means for solving the problem) The first means according to the present invention for achieving the above object is as follows:
A time information output means for outputting time information, contents of a plurality of types of processing related to image formation, and time information related to execution of the processing corresponding to the contents of each processing related to the formation of these images are stored. and a comparison means for comparing the time information output from the time information output means and the time information stored in the storage means, and as a result of the comparison by the comparison means, the time information output means When the time information outputted from the storage means matches the information stored in the storage means, the processing corresponding to the time information among the processes stored in the storage means is sequentially executed.

A second means according to the present invention includes a time information output means for outputting time information, and a plurality of types of processing related to image formation, each of which includes at least processing for detecting a conveyance failure of the medium. a storage means in which time information related to the execution of the process is stored in correspondence with the content of the process and the content of each process related to the formation of these images; and time information output from the time information output unit and the memory; and comparing means for comparing the time information stored in the means, and the time information outputted from the time information output means as a result of the comparison by the comparison means, and the time information stored in the storage means. The present invention is characterized in that when the process for detecting a conveyance failure of the medium and the corresponding time information match, the process for detecting the conveyance failure of the medium is executed.

(Function) The first means according to the present invention includes the contents of a plurality of types of processes related to image formation, and time information related to the execution of the processes corresponding to the contents of each process related to the formation of these images. , for example, is stored in the storage means in the form of a table. Also,
The time information output from the time information output means and the time information stored in the storage means are compared, and when both time information match, the process corresponding to the time information among the processes stored in the storage means are executed sequentially.

Therefore, the number of counters can be reduced, and the burden on the control section can be reduced.

A second means according to the present invention provides information on the contents of each process including at least a process related to a medium conveyance failure, that is, a jam detection, among a plurality of types of processes related to image formation, and each process related to image formation. Time information related to the execution of the process is stored in the storage means in correspondence with the contents of the process. Further, the time information output from the time information output means and the time information stored in the storage means are compared, and among the time information output from the time information output means and the time information stored in the storage means, When the process related to jam detection and the corresponding time information match, the process related to jam detection is executed.

Therefore, it is possible to easily and reliably perform processes related to image formation such as jam detection, while reducing the burden on the control section, without performing dedicated processes related to jam detection.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings.

First, the configuration of an image forming apparatus according to the present invention will be explained with reference to FIGS. 2 to 4.

Four parts 12 serving as paper ejection parts are formed on the upper surface of the apparatus main body 10 shown in FIG. Four sections 13 are provided on the left side as a paper ejection section, and a paper ejection tray 4 is removably attached to the main body 10 of the apparatus 7 in the recessed portion 13. As shown in FIG. 4, a manual feed guide 32 that can rotate in the direction shown in the figure about a fulcrum 30 provided on the device main body 10 is attached to the right side of the apparatus main body 0. A side cover 34 is attached to the lower part of the apparatus body 10 and is rotatable in the direction shown in FIG. 5 about a fulcrum 36 provided on the main body 10 of the apparatus. An operation panel 16 is arranged on the right side of the front face in FIG. 2, and a paper cassette 400.degree. 401, which is detachable from the apparatus main body 10, is attached to the lower part. Also,
Between the paper cassettes 400 and 401, there are font cards for adding functions, cards for application software, etc.
Openings 24a and 24b are provided for inserting the connectors (not shown).

Next, the operation panel 16 will be explained in detail with reference to FIG.

The operation panel 16 includes a liquid crystal display section 60 and an LED display section 70.
and a switch section 80.

The online display 71 displays whether or not it is connected to an external device. That is, when the online display 71 is lit, it indicates that the online mode is on, and when it is off, it indicates that the online mode is on.

The ready indicator 72 indicates that the main body of the image forming apparatus is ready for operation. The data display 73 displays that image information is being transferred. Operator display 74 displays a request to call an operator. The service display 75 displays a request to call a service person. - The mode display 76 displays manual feed mode or automatic paper feed mode.

The menu key 81 is a next page key 81a and a previous page key 81.
It is composed of b. Each time this next page key 818 is operated, a plurality of pieces of menu information displayed on the left half of the liquid crystal display section 60 are incremented. Also, previous page key 8
Each time 1b is operated, the aforementioned plurality of menu information is decremented. Value key 83 is next page key 83a
and a previous page key 83b. Each time the next page key 83a is operated, a plurality of pieces of value information corresponding to the menu information described above are sequentially incremented.

Further, each time the previous page key 83b is operated, the plurality of value information described above are sequentially decremented and displayed. The operator selects or instructs a desired operation by operating the menu key 81 and value key 83.

As shown in FIG. 4, inside the apparatus main body 10, a drum-shaped photoreceptor 202 is provided as an image carrier. a charging device 204, an exposure section 206 for forming an electrostatic latent image, and a developing device 208 for performing a developing process.
, a transfer device 300 including a scorotron, a drum cleaner device 210, and a pre-exposure device 301 are arranged in this order. Among these, the photoreceptor 202, the charging device 204
, a developing device 208, and a drum cleaner device 210,
An electrophotographic process unit that integrates a pre-exposure device 301 and a pre-exposure device 301 is removably provided within the apparatus main body 10.

A laser diode (not shown) is provided in the laser exposure apparatus 100, and the laser beam 102 emitted from the laser diode is condensed by a condensing lens device 118 and sent to a polarizing device ]-08. The polarizer 108 is equipped with a polyhedral mirror 106 that rotates at high speed, and the laser beam 10 reflected by the polyhedral mirror 106 is
2, an Fθ1 non-zero 1101, a reflection mirror 112, and a dustproof lens pass through the lath 114 to scan the exposure portion 206 of the photoreceptor 202.

The developing device 208 includes a magnet roller 220, stirring rollers 222a, 222b, a two-component developer (not shown) consisting of carrier and toner, etc. in a case 224. This electrostatic latent image is developed by conveying toner. Moreover, this developing device 20
A toner replenishing device 226 for replenishing consumed toner is attached to 8.

The tram cleaner device 210 has an elastic blade 232 in a case 230 that is in contact with the photoreceptor 202 and scrapes off toner remaining on the photoreceptor 202 from the photoreceptor 202. This scraped off toner is transferred to the toner storage section 214 inside the case by a conveyance roller 236 inside the case 230.
sent to.

The fixing device 350 includes a heat roller 352 having a built-in heater lamp 351, and a pressure roller 353 that is in pressure contact with the heat roller 352.
As the paper P passes through the gaps 3 to 3, the toner image is fused and fixed on the paper P. The heat roller 352 and the pressure roller 353 are connected to the lower casing 354 and the upper casing 3.
56, and has a structure that prevents heat from escaping to the outside so as to ensure a favorable temperature atmosphere necessary for fixing. This heat roller 352 is equipped with a cleaner 35.
8 are in contact with each other, and the heat roller 352 is cleaned so that good fixing can always be performed. Further, the surface temperature of the heat roller 352 is detected by a thermistor 360, and temperature control is performed to maintain the temperature necessary for fixing.

Also, within the upper casing 356 and the heat roller 35
A paper peeling guide 368 is disposed near the downstream side of the contact area between the paper P 2 and the pressure roller 353 to ensure that the leading edge of the paper P guided to the fixing device 350 is peeled off from the heat roller 352. . Note that a paper guide 366 is provided on the paper exit side of the fixing device 350 to guide the fixed paper P to a pair of paper ejection rollers 408.

A gate device 1442 is provided on the downstream side of the paper ejection roller pair 408 to switch the conveyance path of the paper P to the paper ejection section on the paper ejection tray 14 side or the paper ejection section on the paper ejection roller pair 409 side. As shown in the figure, two positions can be selected around the fulcrum 444: the solid line side and the broken line side.
As a result, the paper P is conveyed to one of the paper discharge sections.

An image transfer section 209 formed between the photoreceptor 202 and the transfer device 300 is provided within the apparatus main body 10.
On the upstream side of the image transfer section 209, there are a transfer guide roller 422, a paper guide pair 420, and an aligning roller pair 4.
06 is provided. The aligning roller pair 406 constitutes a conveying means for conveying the paper P, and
The aligning roller pair 406 has an aligning switch as a detection means for detecting the arrival of the paper P.

On the downstream side of the image transfer unit 209, a paper conveyance guide 416,
A fixing device 350, a pair of paper ejection rollers 408, and a pair of paper ejection rollers 409 are arranged.

These discharge roller pairs 408 and 409 are provided with static eliminating brushes 412 and 413 that contact the non-image forming side of the paper P along the conveyance direction.

The pair of paper discharge rollers 408 and 409 constitute a conveyance means for conveying the paper P. Further, the paper discharge roller pair 408 has a detection switch which is a detection means for detecting the arrival of the paper P.

At the bottom of the device main body 10, a paper feed roller and a paper cassette 4 are installed.
00 and 401 are arranged, and a paper empty switch (not shown) for detecting the paper P in the paper cassettes 400 and 401 is provided near the paper feed roller. In addition, case 45 of paper cassettes 400 and 401
A paper size detection switch (not shown) is provided on the side of the paper cassette 400, 470 to detect the paper size of the stored paper P. A mounting detection switch (not shown) is provided for detection.

A paper transport path 42 is provided on the right side of the paper cassettes 400 and 401.
4 is provided, and this paper conveyance path 424 includes paper guides 431, 432, 433, a pair of paper conveyance rollers 440,
It consists of 441.

The paper guide 431 is configured integrally with the side cover 34. On the downstream side of the pair of paper transport rollers 440, there are paper guides 435, 4 that guide the paper P to the pair of aligning rollers 406.
There are 36. Further, a paper transport path 425 for manual paper feeding is provided above the paper transport path 424, and this paper transport path 425 merges with the paper transport path 424.

An aligning switch 630 is provided near the aligning roller pair 406, and a paper ejecting switch 414 is provided near the paper ejecting roller pair 408. It is designed to be detected.

On the back side of the apparatus main body 10, there is an engine control board (not shown) equipped with an engine control circuit that controls each device provided in the apparatus main body 10 to control operations to complete the electrophotographic process, and a power supply ( ) etc. are arranged.

A printer control board 602 equipped with a printer control circuit that controls the operation of the engine control circuit is disposed in the board storage section ]-8 provided between the paper cassettes 400 and 401. Up to two printer control boards 602 can be installed depending on the degree of function addition (for example, adding more types of fonts, kanji, etc.). Further functions can be added by inserting a function-adding font card (not shown) into the two provided font card connectors 61.0a and 610b.

In the image forming operation, the drum-shaped photoreceptor 202 is rotated and the surface potential of the photoreceptor 202 is kept constant by the action of the pre-exposure device 301, and then uniformly maintained by the action of the charging device 204. charged and laser exposure device 1
The laser beam 102 emitted from the photoreceptor 202
It irradiates and exposes the top of the image to form an electrostatic latent image corresponding to the image signal.

This electrostatic latent image on the photoreceptor 202 is developed by the developing device F2O3 and is visualized as a toner image, which is then transferred to the image transfer unit 202.
Sent to 09.

On the other hand, the paper P taken out from the paper cassette 400 or 401 in synchronization with this toner image forming operation is sent to a paper guide 432 or 433, passes through a paper conveyance path 424, passes through a pair of aligning rollers 406, and a pair of paper guides. 420
The toner image is sent to the image transfer unit 209 via the transfer roller 422, and the toner image previously formed on the photoreceptor 202 is transferred onto the paper P by the action of the transfer device 300. Next, the paper P passes through the paper transport path 410 guided by the transport guide 416 and is sent to the fixing device 350, where the toner image is melted and fixed onto the paper P.

Further, the paper P fed from the manual feed guide 32 passes through the manual paper feed conveyance path 425, joins the paper conveyance path 424, and the same operation as described above is performed.

The paper P that has passed through the fixing device 350 is transferred to a pair of paper ejection rollers 408
and sent to the gate device 442.

The position of the gate is selected in advance according to instructions from the host computer, and if the upper position is selected, the paper P is sent to the upper paper ejection section and is passed through the paper ejection roller pair 409 onto the top cover. is discharged. Also, if the lower position is selected as the gate position,
The paper P is discharged onto the paper discharge tray 14.

Note that after transferring the toner image onto the paper P, the photoreceptor 2
The residual toner remaining on the photoreceptor 2 is mechanically removed by a tram cleaner device 210 having an elastic blade 232.
02 and collected in the toner storage section 214 in the apparatus by the conveyance roller 236.

First, the configuration of the engine control section will be explained.

FIG. 1 is a block diagram of the engine control section 600 and its peripheral parts, and FIG. 5 is a block diagram of the engine control circuit 601 and its peripheral parts. In the figure, 603 is a power supply device of the image forming apparatus, which outputs +5V and +24V when the main switch 26 is turned on. +5■ is supplied to the engine control circuit 601, and is further connected to the printer control circuit 70.
1. The engine control circuit 601 uses a time information output means for outputting time information, and compares the time information output from the time information output means with time information stored in a storage means to be described later, and executes each process. It has a means of judgment.

On the other hand, +24 power is connected to the cover switch 611, then supplied to the engine control circuit 6()1, and then to the scanner control circuit 101, the high voltage main circuit 605, and the mechanism drive circuit 607, and the semiconductor laser 120. , mirror motor 121, high voltage power supply 605, pre-exposure device 30], main motor 612, cassette paper feed solenoid 6] 3a, 613b, aligning solenoid 61
4. It is used as a power source for driving the toner replenishment solenoid 615, the gate control noid 617, the cooling fan 616, and the like.

Furthermore, in the power supply device 603, a zero-cross switch type heater lamp drive circuit (not shown) consisting of, for example, a phototriac coupler and a triac is provided for driving the heater lamp 351, and the light emitting side LED of the phototriac coupler is The above-mentioned +24V is used as the driving power source. In the heater lamp drive circuit with this configuration, when the LED on the light emitting side is turned on or off, the photo triac on the light receiving side turns on or off at the zero cross point of the AC power supply, and the triac, which is the main switch element in the next stage, is turned on or off. Then, the upper clamp 351 is energized and cut off from AC power. And a control signal 668 for turning on and off the light emitting side LED.
is supplied from the engine control circuit 601 to the power supply device 603, and the thermistor 360 provided in the fixing device [350] is connected to the engine control circuit 601.

Further, the cover switch 611 is turned off when the top cover 40 is rotated upward and when the side cover 34 is opened. - Therefore, when the top cover 40 or the side cover 34 is opened, +24V is cut off by the switch 611, so the semiconductor laser 120 and the mirror motor 121 are
, the high-voltage power supply 605, the main motor 612, the solenoids 613a, 613b, 614, 615, 61.7, the cooling fan 616, the heater lamp 351, etc. are stopped, and the operation is stopped. It is designed so that there is no problem even if you touch it.

In FIG. 5, the CPU 650 is the engine control section 600.
It performs overall control and operates according to a control program stored in the ROM 651. RAM652 is C
It is used as a work buffer for the PU 650. E'
The PROM 653 stores the total number of prints and the number of sheets used by the electrophotographic process unit 200, that is, the number of sheets printed after the electrophotographic process unit 200 was replaced with a new one. Further, the E2FROM 653 is a storage means that stores contents of a plurality of types of processing related to image formation and time information related to the execution of the processing in correspondence with the contents of each processing related to the formation of these images. Specifically, in the form of a table as shown in FIG. 8, instruction IDs, which are the contents of a plurality of types of processes, and execution times, which are time information related to the execution of each process, are stored. Also E2FROM65
3, the number of each instruction ID and the contents of the instruction corresponding to this instruction ID number are stored in the form of a table, as shown in FIG. The printer control circuit interface 654 includes:
Interface signal 6 with printer control circuit 701
Mediate the delivery of 67.

The laser modulation control circuit 655 controls the semiconductor laser 120 to be forced to turn on periodically in order to generate a laser light detection signal 665 to be described later, and also controls the printer control circuit 7 by the interface signal 667.
It modulates and controls the semiconductor laser 120 according to image data sent from 01, and outputs a laser modulation signal 664 to the scanner control circuit 101. Output register 65
6 is a mechanism drive circuit 607 and a scanner control circuit 10]
, the high-voltage power supply 605, and the control signal 663°666.669,6 that controls the heater lamp drive circuit, respectively.
Outputs 68. The voltage generated by the thermistor 360 and the toner sensor 624 is input to the A/D converter 657, and this voltage value is converted into a digital value.

The input register 658 contains the state signals of the paper empty switches 620a, 620bSvI: the paper switch 414, the attachment detection 428, the size switch 426°427, and the aligning switch 630, and the +24
V on/off status signals are input. The option control circuit interface 648 mediates the exchange of an interface signal 662 with an option control circuit (not shown).

Further, the internal bus 659 is connected to the CPU 650 and the ROM 6.
51, RAM652, E2 PROM653, printer control circuit interface 654, laser modulation control circuit 6
55, output register 656, A/D converter 657,
Data is exchanged with the input register 658.

In this embodiment, the CPU 650, ROM 651, RAM
652, an A/D converter 657, and part of the output register 656 and input register 658 are realized by using a one-chip micro combi coater 649.

The mechanism drive circuit 607 is provided with a drive circuit for driving a motor, a solenoid, etc., and the control signal 663 output from the output register 656 is
On and off are controlled by the binary values of lJ and rOJ.

For example, each drive circuit is turned on when it is "1" and turned off when it is "0", and the pre-exposure bag ff301, the main motor 612
, + to solenoids 613a, 613b, 614, 615
It is designed to energize or cut off 24V.

The scanner control circuit 101 is provided with a drive circuit for a semiconductor laser 120 and a mirror motor 121, and the semiconductor laser 1.20 is turned on by r]JrOJ of the laser modulation signal 664 output from the laser modulation control circuit 655. The mirror motor 121 is turned off and the control signal 666 rlJ output from the output register 656
On/off is controlled by rOJ. Further, when the laser beam 1.02 passes through the laser beam detection sensor 122, it is detected and sent as a laser beam detection signal 665 to the laser modulation control circuit 655.

Further, from the high voltage power supply 605, the developing device section 208
, a developing bias 604 a and a band 111604 c to the charging device section 204 and the transfer device section 300, respectively.

Each high voltage of the transfer 604b is output. These on,
When off, the control signal 66 output from the output register 656
Controlled by rlJ rOJ of 9.

As described above, within the engine #11 section 600, power is supplied to each electric circuit via the engine control circuit 601, and rO is output from the engine control circuit 601.
It is controlled by a binary signal from JriJ. This engine control section 600 and a printer control section 700 described later
and are coupled by an interface signal 667.

Next, the configuration of printer control section 700 will be explained.

FIG. 6 shows the printer control section 700 and its peripheral parts. In the figure, the CPU 741 is the printer control unit 7.
This controls the entire 00. The ROM 742 stores a control program, and the CPU 741 operates according to this program. In addition, the above ROM7
42 stores data related to the paper P such as a password, top margin, left margin, paper type, etc., which are verified when changing data. The RAM 743 is used as a page buffer for temporarily storing image booters sent from the host device 749, and is used as a page buffer for temporarily storing images sent from the host device 749.
It is used as a working buffer. Expanded memory 74
4 is used when the image data sent from the host device 749 is a large amount of data such as bitmap data.
AM743 is a large capacity memory used when it is not possible to store data for one page. Video RAM74
5 stores image data developed into a bit image, and this output is sent to a serial-parallel conversion circuit 74.
6. The serial-parallel conversion circuit 746 converts the image data developed into a bit image in the video RAM 745 and sent as parallel data into serial data (7) and sends it to the engine control circuit 601.

The host interface 748 transfers data between the printer system mK700 and a post device 749, which is composed of, for example, an electronic computer or an image reading device, and uses two types of transfer: a serial transfer line 750a and a parallel transfer line 750b. It has a line.

Then, it can be used appropriately depending on the type of data transferred to and from the host device 749. The engine interface 751 mediates the exchange of the interface signal 667 between the printer control circuit 701 and the engine control circuit 601.

The connection circuit 753 connects the font card 707 to the connector 7.
10a, 710b or connector 71
When removing the font card 707 from the font card 710a or 710b, shut off the power supply and signal line supplied to the font card 707 to prevent data stored in the font card 707 from being destroyed by noise generated during insertion or removal. It is intended to prevent

The operation panel control circuit 757 controls displaying a guidance message on the liquid crystal display section 60 of the operation panel 16, and
It controls the lighting, extinguishing, and blinking of the ED display 70, or controls the sending of data manually entered from the switch 80 to the CPU 741. In addition, internal bus 752
The above CPU741, ROM742, RAM743,
This is a bus for exchanging data with the expansion memory 744, video RAM 745, operation panel control circuit 757, host interface 748, engine interface 75], and connection circuit 753.

Further, the font card 707 is a non-volatile memory, for example, a static RAM with battery backup,
It is composed of E2 PROM, EPROM, mask ROM, etc.

These font cards 707 store, for example, character fonts, emulation programs, and the like.

Next, a table used to control a series of printing operations will be explained. In a series of printing operations after receiving a print command, the timing of each printing operation is strictly set according to a table as shown in FIG. 8 in order to obtain a high-quality image.

Specifically, as shown in FIG. 9, each operation is assigned an instruction ID number, and
One byte of hexadecimal data indicating each operation by an instruction ID number and instruction data indicating the operation contents corresponding to this instruction ID are set.

The execution time shown in FIG. 8 is the time from receiving the print command to starting the operation, and is set by 2-byte hexadecimal data. This execution time is set based on the cycle of a free running counter managed by CPU 650 of engine control section 600. This free-running counter is a 2-byte counter that is incremented once every 10 seconds, and when it reaches a predetermined value, it continues to increment from 0 again. Therefore, for example, if the execution time shown in FIG. 8 is ro 190J, it means 4000 vata seconds.

Next, the control processing executed based on the table shown in FIG. 8 will be explained with reference to the flowchart shown in FIG. 10.

When a command related to printing is input from the printer control unit 700 in step SPI, the engine control unit 600 stores the value of the free running counter as the start timing of a series of printing operations. Next, in step SP3, the value of the instruction pointer is set from "0" to "1". The value of this instruction pointer indicates how far out of the series of printing operations shown in FIG. 8 has been completed, and is incremented each time each operation is completed.

At step SP5, the execution time of the next operation is calculated by adding together the execution time on the table of FIG. 8, which is indicated by the value of the instruction pointer, and the start timing. In step SP7, step SP5
The execution time calculated as follows is compared with the value of the free running counter, and when the two values match, the process proceeds to step SP9 and the operation related to printing, that is, the instruction is executed. When the instruction is executed in step SP9, the process advances to step SP11 and the instruction pointer is incremented. Next step 5P13
Then, it is determined whether or not the series of printing operations shown in FIG. 8, that is, the sequence, has ended, and if it has not ended, the process returns to step SP5.

Similarly, the instruction pointer is incremented each time each operation is executed in a series of printing operations, and when the value of this instruction pointer exceeds the number of instructions shown in Figure 8, the series of printing operations ends. judge things. In this way, each instruction set in chronological order in FIG. 8 is sequentially executed.

As described above, by storing the value of the free running counter as the start timing of a series of printing operations when a command related to printing is input, each instruction can be reliably executed without providing a dedicated counter.

Next, the operation of the printer control circuit section 700 will be explained using the flowchart shown in FIG.

For example, if the image forming apparatus is offline and the CP
When it is determined that the U741 is offline (step 5101), the host device 7
It is checked whether the printing process for the data received from 48 has been completed (step 31.02), and if it has not been completed, the process branches to step 5112 to continue the printing process.

If the printing process is completed, the above step 5101,
By repeatedly executing step 8102, an idling state is created and the image forming apparatus waits for it to be placed on-line.

On the other hand, if the image forming apparatus is online, it is checked whether the data sent from the host device 748 is a command (step 5103), and if it is a command, the operation corresponding to the command is performed (step 5104).
), if it is not a command, the execution of the above command is skipped and the process advances to step 5105. For example, the above command is
It defines the attributes of the following data and controls the printer without sending or receiving data.

Next, it is checked whether the page buffer provided in the RAM 743 as a buffer for data reception is full (step S i 05 ), and if it is not full, the data sent from the host device 749 is used as an image. It is checked whether it is data (step 5106). If it is not image data, the process returns to step 5101 and waits for a command or image data to be received by repeating the above series of steps. When it is determined in step 5106 that the image data has been received in a state where the image data is not displayed, the received image data is sequentially stored in the page buffer (step 5107). Next, it is checked whether storage for one page has been completed (step 3).
108), provided on the operation panel 16 if not completed,
The data display 73 of the LED display 70 that is currently displayed starts blinking (step 3110). Next, Ste.
By returning to block 5101 and executing the above series of steps, the process waits until one page's worth of image data is accumulated in the page buffer. When it is determined that the storage of image data for one page has been completed by repeatedly executing the above series of steps, the data display 73 is turned off (step 51.09), and the data reception process is ended. . Then, the process moves on to the printing process after step S12.

Note that in step S5 above, if it is determined that the page/(-sofa is full, the data reception operation is stopped in step 5111), and in this case also in step S11.
The process moves on to print processing from step 2 onwards. In this way, during the data reception operation, the data lamp is blinked to notify the operator.

Next, when one page's worth of image data has been stored in the page buffer, it is checked whether the scan buffer provided on the video RAM 745 is full (step 51.12). Here, if it is determined that the scan buffer is not full, the CPU 74 converts it into the image data of the character image stored in the page buffer and stores it in the video RAM 7 as a scan buffer.
45 (step 5113). On the other hand, if the scan buffer is full, step 5113 is skipped.

Next, it is checked whether the print command has already been sent (step 5114), and if it has been sent, the following print command sending processing (steps 5115 to 5119) is skipped and the process advances to step 5120.

On the other hand, if the print request has not been sent yet, it is checked whether a print request has been sent (step S i 15 ). Here, if it is determined that no print request has been issued, it is determined that the print preparation on the engine side has not been completed, and the process returns to step 5101 to re-execute the above-mentioned series of steps to process the print request. Wait for it to be served. On the other hand, if it is determined that a print request has been issued, a print command is sent (Step 5119).Next, it is checked whether a VSYNC command has been sent (Step 5120).
). Then, if it is determined that the VSYNC command has not been sent, it is checked whether a VSYNC request has been issued from the engine side (Step 5121).
. If it is determined that a VSYNC request has not been issued, the process returns to step 5101 and waits for a VSYNC request to be issued without executing the above series of steps again. Then, in step 5121, VSYN
When it is determined that a C request has been issued, VSYN
Send the C command to the engine side (Step 5122)
, returning to step S10-1, horizontal synchronizing signal H8Y
The state shifts to a state where it waits for the NCO and video clock VCLKO to be manually input.

In this state, in step 5120 above, VSY
When it is determined that the NC command has already been sent, it is checked whether the transfer of image data for -1 page has been completed (step 5126), and if the transfer of image data has not been completed, , the image data of the bit image stored in the scan buffer is sent to the horizontal synchronization signal HSYNC.
It is sent to the engine side in synchronization with O and video clock VCLKO (step 5125).

On the other hand, the CPU 741 returns to step 5101 and waits for the transfer of one page of image data to be completed while executing the series of steps described above again.

When the transmission of image data for one page is completed in this way, the process returns to step 5101, and the printer control circuit 700
returns to its initial state and becomes ready to transfer the next page of image data.

Next, a process related to detecting an abnormality related to conveyance of paper P, that is, detecting a jam will be described.

FIGS. 11 to 13 show timing charts when jam detection is performed in accordance with detection information from a detector disposed near the paper P supply section, for example, an aligning switch.

First, the normal operation will be explained with reference to FIG. As shown in FIGS. 11(A) and 11(B), at time t1 when conveyance of the paper P starts, jam flags related to paper feeding at the leading edge and trailing edge of the paper are set. When the leading edge of the paper P reaches the aligning switch at time t3 when time T3 has elapsed since the paper P has been conveyed, the aligning switch is reversed from "0" to "1" as shown in FIG. 11(C). . As a result, the jam flag related to the paper feeding at the leading edge of the paper is cleared.

Time t7 after time T7 has elapsed since the paper P was further conveyed
When the rear end of the sheet P reaches the aligning switch, the aligning switch is reversed from "1" to "0" as shown in FIG. 11(C). As a result, the jam flag related to paper feeding at the trailing edge of the paper is cleared.

Next, with reference to FIGS. 12 and 13, the operation when the paper P is not conveyed normally will be described.

If the leading edge of the paper P does not reach the aligning switch after the jam flags related to the feeding of the leading and trailing edges of the paper are set at the time tI of the start of conveyance of the paper P, the 12th aligning switch is set.
As shown in Figure (C), the aligning switch remains at "0", and the jam flag associated with the leading edge of the paper remains unchanged without being cleared. As a result, Figure 12 (D
), the predetermined time T is longer than the required time T3 from the start of transport of the leading edge of the paper P to the alignment switch.
At time t5 after 5 lapses, it is determined that a jam related to the leading edge of the paper P has occurred. This is executed as the instruction ID81 mentioned above.

Similarly, if the trailing edge of the paper P does not reach the aligning switch, the aligning switch remains at "1" even after time T7, as shown in FIG. The jam flag remains as it is without being cleared. As a result, as shown in FIG. 13(D), a time t after a predetermined time T9 has elapsed, which is longer than the time required T7 from the start of transport of the trailing edge of the paper P to the alignment switch.
In step 9, it is determined that a jam related to the trailing edge of the paper P has occurred.

14 to 16 show timing charts when jam detection is performed in accordance with detection information from a detection switch disposed near the paper P discharge section. Paper P
Since the distance of the conveyance path from the supply section to the detection switch is longer than the distance to the above-mentioned aligning switch, the first
As shown in FIG. 4, the sheet P whose conveyance has started reaches the detection switch after a time T4, which is longer than the time T3. Therefore, when the paper P is not conveyed normally, the leading edge of the paper P is detected at time t6 after a predetermined time T6, which is longer than the required time T4 from the start of conveyance of the leading edge of the paper P to the detection switch, as shown in FIG. It is determined that a jam has occurred.

Similarly, if the trailing edge of the paper P does not reach the detection switch, as shown in FIG. At time tIQ, it is determined that a jam has occurred at the trailing edge of the paper P.

As described above, since the configuration is configured to perform jam detection processing in response to detection information from a plurality of detection means provided at appropriate positions on the conveyance path, it is possible to reliably and appropriately determine the occurrence of a jam. can.

Next, another embodiment according to the present invention will be described with reference to FIG.

In the table shown in Figure 8, each instruction!
The effective time corresponding to D indicates the time from receiving the print command to starting the operation, whereas the table shown in FIG. 17 shows the instruction IDs arranged according to the order of execution. The execution time is the time from the end of the process of the instruction ID to be executed immediately until the corresponding instruction ID is executed. This execution time may be set using, for example, 2 bytes of hexadecimal data.

Therefore, each time the processing of each instruction ID is completed, the free running counter is reset to count the time until the next instruction ID is executed.

For example, the free running counter is reset at the same time as the content of instruction ID number 51 shown in FIG. 17 is executed, and when the predetermined time Ta2 has elapsed, the content of the next instruction ID number 12 is executed.

The same applies below.

By configuring the free running counter to be reset each time the processing of each instruction ID is completed and counting the time until the next instruction ID is executed, each instruction ID can be reliably executed. .

[Effects of the Invention] As explained above, according to the first means of the present invention, the contents of each process related to image formation and the clock information related to the execution of each process are stored, and the clock information is stored. Since the clock information output from the output means is referred to and the corresponding processes are sequentially executed, the number of counters can be reduced, and the burden on the control section can be reduced.

Further, according to the second means of the present invention, among the plurality of types of image formation, at least a process for detecting a medium conveyance failure is included, so that a dedicated jam detection process is included. Processes related to image formation, such as jam detection, can be easily and reliably performed without performing any processing, reducing the burden on the control unit.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an engine control unit and its surrounding parts, FIG. 2 is a perspective view of an image forming apparatus according to the present invention, and FIG.
The figure is an explanatory diagram of the operation panel, Figure 4 is an internal configuration diagram of the embodiment shown in Figure 2, Figure 5 is a block diagram showing the internal configuration of the engine control circuit, and Figure 6 is a printer control circuit and its FIG. 7 is a block diagram showing peripheral devices, FIG. 7 is a flowchart showing processing in the printer control circuit, FIG. 8 is a table showing instruction ID execution times, and FIG. A table showing the contents of the corresponding instructions, FIG. 10 is a flowchart showing control processing based on the table in FIG. 8, and FIGS. Timing chart when performing jam detection according to detection information, 14th
16 to 16 are timing charts when jam detection is performed in accordance with detection information from a detection means placed near the paper ejecting section, and FIG. 17 is each instruction used in another embodiment of the present invention. It is a table showing the execution time of ID. 406... Aligning roller pair 408... Paper ejection roller pair 600... Engine control section

Claims (2)

[Claims] (1) A time information output means that outputs time information, the contents of multiple types of processing related to image formation, and time information related to the execution of the processing corresponding to the contents of each process related to the formation of these images. and a comparison means for comparing the time information outputted from the time information output means and the time information stored in the storage means, and as a result of the comparison by the comparison means, the time information is If the time information output from the information output means matches the information stored in the storage means, among the processes stored in the storage means, processes corresponding to the time information are sequentially executed. image forming apparatus. (2) A time information output means for outputting time information, the contents of each process including at least a process for detecting medium conveyance defects among multiple types of processes related to image formation, and information on the formation of these images. a storage means in which time information related to the execution of the process is stored in correspondence with the content of each process, and time information output from the time information output means and time information stored in the storage means are compared. comparing means, and processing for detecting a conveyance failure of the medium between the time information output from the time information output means and the time information stored in the storage means as a result of comparison by the comparison means. An image forming apparatus characterized in that a process for detecting a conveyance failure of the medium is executed when the time information and the corresponding time information match.