JP3229621B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer or a digital copying machine used as a computer terminal or the like.

[0002]

2. Description of the Related Art An image forming apparatus such as a laser printer has an image data processing section for converting a print code into image data for laser modulation, and a sequence control section for controlling an image forming process operation. When the image data processing unit prepares one page of laser modulation image data,
Send a print start command to the sequence control unit, and when the sequence control unit is in a print executable state,
When the print start command is received from the image data processing unit, the printing is started immediately.

[0003]

However, in such an image forming apparatus, the speed of consumption of electrophotographic image forming processes (image forming processes) and sequence devices (motors, solenoids, etc.) for paper conveyance is high. There were drawbacks.

Specifically, in recent years, printed images have become complicated due to the development of page description languages, and
Since the amount of image data in a page has significantly increased, the time required for developing the image data into a bit image has been increased. On the other hand, the electrophotographic image forming process of the image forming apparatus (parts other than image development) has been accelerated, and it has become possible to form several tens or more images per minute.

However, even in an image forming apparatus capable of high-speed printing, if the development of image data is delayed, the paper interval increases, and for example, as shown in FIG. 8, intermittent printing (after the discharge of the preceding paper is completed, the next (Start printing). Since the above-described sequence devices are generally consumed due to their driving time, in such a low-duty printing method, the driving time of the printer is shorter than the continuous printing as calculated from the following equation. Longer, faster consumption.

Here, the driving time required to print one sheet is T1, T1 = (Lp + Lt) / V, where V is the sheet passing speed, Lp is the sheet length, and Lt is the sheet passing path. The drive time Tn when performing intermittent printing on N sheets is Tn = T1 × N.

On the other hand, when printing is continuously performed on N sheets, the driving time Tn 'is Tn' = {Lp.times.N + Lt + Lg.times. (N-1)} / V, where Lg is the paper interval. Becomes Therefore, when the paper interval Lg is smaller than the paper passage path length Lt (usually, Lg <Lt), it can be understood from the following equation that the drive time is shorter when printing is performed continuously. Tn−Tn ′ = (Lt−Lg) · (N−1) / V

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents a decrease in print duty due to a delay in processing time in the image data processing unit as described above, and extends the life of the entire apparatus. With the goal.

[0009]

In order to achieve the above object, the present invention has an image data processing section for converting a print code into laser modulation image data, and a sequence control section for controlling an image forming process operation. When the image data processing unit prepares laser modulation image data for one page,
In an image forming apparatus provided with means for transmitting a print start command to a sequence control unit, an image data processing unit
The print start command is
Send the print instruction stack specification command to specify the number of
Means for transmitting image data to the sequence control unit.
Received a print command stack designation command from the control unit
The print stack specified by that command.
Stack number setting means for setting the number of stacks of stack instructions
And a print start command from the image data processing unit
Check the argument type of the instruction.
Print start command checking means for
Print start command argument from the check result
Is recognized as a code indicating a forced print command
To cancel the setting by the stack number setting means
Means and check by print start instruction check means.
Argument of print start command is
If it is recognized as a code indicating a normal print command,
Print start stacking print start instruction
Instruction stack means and a print start command
The stack number of the command is
Start printing when the number of tacks exceeds
And means for performing such operations.

[0010]

[0011]

According to the image forming apparatus of the present invention, the sequence control unit sends the print instruction stack from the image data processing unit.
When a specified command is received,
Set the number of stacks for the specified print start instruction
You. A print start command is sent from the image data processing unit.
, The argument type of the instruction
Check, and print start order from the check result
The argument of the command is a code indicating a forced print command and
If recognized, cancel the setting of the number of stacks, and
Argument of print start command from check result
Is recognized as a code indicating a normal print command,
Stack the print start instruction and stack
If the number exceeds the number of stacks set above,
Start the operation. Therefore, the number of stacks
If "1" or more, multiple pages from the image data processing unit
Minute print start command (However, the argument is usually
Print when a code indicating a print command is received
Since the operation is started, printing is continuously performed on a plurality of sheets, and a decrease in print duty due to processing time in the image data processing unit is prevented. Therefore,
The drive time of each drive device is reduced, and the life of the entire device is extended. In addition, prints received from the image data processing unit
Argument of start instruction indicates forced print instruction
If it is a code, the set stack number becomes “0”,
The print operation starts immediately and the image data
Processing unit prepares one page of laser modulation image data
The image data must be printed every time
Prepares multiple pages of laser modulation image data
For laser modulation per page
Even if the image data becomes huge,
Problems such as the following (1) or (2) can be avoided. (1) When the image data processing unit is unable to prepare the image data for laser modulation for a plurality of pages due to memory shortage double
Print start instruction for several pages (However,
Is usually sequence control)
Print operation is started because it cannot be sent to the
Can not do it. (2) Prepare laser modulation image data per page
If it takes a lot of time to complete,
Print start command for a page (2 or 3 pages)
Argument is usually a code indicating print command)
To the print control unit to start the printing operation.
It takes a lot of time even if you
As a result, the printing speed may be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a sectional view showing a schematic configuration of a laser printer according to one embodiment of the present invention.

This laser printer has a main body 1 and a table 2
The main body 1 is provided with two upper and lower paper feed trays (cassettes) 3 and 4 capable of storing 250 cut sheets each detachably, and has a first paper output stacker 6 and a second paper output stacker 7 at the upper part. Are provided in two stages, and a third discharge stacker 8 is provided at the rear of the discharge tray 9 so as to be openable and closable in the direction of arrow A in FIG.

In the main body 1, a photosensitive drum 10 constituting an image forming section of a printer engine and a charging charger 1 are provided.
1, a laser writing device 12, a developing device 13, a transfer charger 14, a cleaning unit (cleaner) 15, a fixing device 16, a registration roller pair 17, a plurality of conveyance rollers, a paper conveyance unit including a paper guide plate and the like. 18 and
And a high-voltage power supply unit 19. Furthermore, body 1
Each substrate of an image data processing unit (printer controller) 21 for controlling the laser printer and a sequence control unit (engine driver) 30 is mounted in the inside.

On the other hand, the table 2 is equipped with a large-volume paper feed tray 5 capable of storing 1000 cut sheets, and has a plurality of conveying rollers constituting a duplex unit and a paper guide plate for duplex printing inside. And a reversing paper feeding unit 23 and the like. In addition, a front cover is provided on the outside front (not shown) of the main body 1 so as to be openable and closable. When the inside of the main body 1 is to be inspected or the like, the cover is opened to perform inspection work or the like of each part.

Next, the operation of each of the above components will be briefly described. When the print sequence is started by the sequence control unit 30, paper feeding is started from a selected one of the paper feed trays 3 and 4 or the large-volume paper feed tray 5 at a predetermined timing by driving a main motor (not shown). The paper is temporarily stopped in a state where the leading edge of the paper is held by the pair of registration rollers 17.

On the other hand, the photosensitive drum 10 rotates in the direction of the arrow in FIG. 2, and a laser beam modulated according to video data by a laser writing device 12 is applied to the surface charged by the charging charger 11 in the drum axial direction. Irradiation and exposure are performed while main scanning is performed to form an electrostatic latent image.

The latent image is developed with toner from the developing device 13 and a pair of registration rollers
After being transferred to the paper fed by the transfer charger 14, the transferred paper is separated from the photosensitive drum 10, conveyed to the fixing device 16, and thermally fixed, and further, the paper heated or fixed, that is, the print paper is Send it to the paper output unit.

At this time, a first discharge stacker 6 or a second discharge stacker 7 located at the upper part of the printer or a third discharge stacker 8 located at the rear of the printer via a discharge transport section 18 as a discharge section. Is discharged to the discharge stacker selected in any one of the above.

Normally, one of the first discharge stacker 6 and the second stacker 7 is selected. However, in a special case such as when an easily curlable paper such as an envelope or a postcard is used, the third discharger 6 is used.
The discharge stacker 8 is selected. However, when the paper discharge port 9 is closed and the paper cannot be discharged, the third paper discharge stacker 8 cannot be selected.

By the way, when double-sided printing is selected, the paper printed on one side is sent to the table 2 by changing the transport path. Then, once the sheet is sent to the reversing section 22 for double-sided printing, the conveyance direction is reversed (switchback), the sheet is conveyed to the reversing sheet feeding section 23 and made to stand by, and is sent to the main body 1 at a predetermined timing. Similarly, printing is performed on the other side, and then the sheet is discharged to one of the sheet discharge stackers.

FIG. 3 is a block diagram showing a schematic configuration of a control section of the laser printer. The control section of this laser printer is constituted by the image data processing section 21 and the sequence control section 30 also shown in FIG.

The image data processing unit 21 includes a computer,
Image data sent from a host system such as a word processor is converted into laser modulation data, a feed selection command, a discharge selection command, a print start command (print start command), a print instruction stack designation command, a print mode (one-sided mode) which will be described later. , Double-sided mode, etc.) are converted into commands such as selection commands, and when they are arranged for one page, various commands including each command and laser modulation data for one page are sequentially sequenced at a predetermined timing through a serial communication path. It is sent to the control unit 30.

The sequence control unit 30 controls a printing operation in accordance with each command from the image data processing unit 21 (hereinafter, abbreviated as “CPU”) 3.
1, a ROM 32 for storing a program for operating the CPU 31, a command register area and a print instruction stack counter (C_F) as shown in FIG.
F), a RAM 33 used for a stack number setting register (S_REG), a storage address pointer (IN_PTR), a command buffer area, and the like, and the image data processing unit 2
1 and a serial I / O interface 34 for transmitting and receiving various serial data, receiving signals output from sensors and switches, the electrophotographic image forming process shown in FIG. Equipment (motor,
And a parallel I / O interface 35 for transmitting a drive signal to a solenoid or the like.

Next, a command according to the present invention transmitted from the image data processing section 21 to the sequence control section 30 will be described. The paper feed selection command is
4 or the large-volume paper feed tray 5, and is assigned the ASCII code "I". The discharge selection command instructs selection of one of the first discharge stacker 6, the second stacker 7, and the third discharge stacker 8, and is assigned an ASCII code "O".

The print start command includes a paper feed start command and a print start command. The paper feed start command is a command to start feeding paper from the selected paper feed tray and to convey the paper to the registration roller pair 17 (image leading edge synchronization mechanism) shown in FIG.
II code 'FF' is assigned. The print start command is used for the electrophotographic imaging process (charging, exposure, development,
Transfer, fixing), and ASCII
Code 'VT' has been assigned.

The print command stack designation command designates a print start command (number of pages) that can be stacked, and is assigned the ASCII code 'S'.

Each of these commands is composed of 2 bytes. The first byte indicates the type of instruction (hereinafter referred to as "operand"), and its most significant bit (MSB)
Is "0". The second byte represents the content of the selection (hereinafter referred to as “argument”), and the most significant bit is “1”.

The configuration of the above-described paper feed selection command, paper discharge selection command, paper feed start command, and print command stack designation command will be described below. 1) Feed selection command Operand: ASCII'I '(49 hex) Argument: 81 hex Upper feed selection At this time, reg1 = 01 hex 82 hex Lower feed selection At this time, reg1 = 02 hex 83 hex Mass feed selection At this time, reg1 = 02 hex

2) Discharge selection command Operand: ASCII'O '(4Fhex) Argument: 81 hex Upper discharge selection At this time, reg2 = 01 hex 82 hex Lower discharge selection At this time, reg2 = 02 hex 83 hex Horizontal discharge selection At this time, reg2 = 03hex

[0031]

[0032]

The registers reg1 and reg2 are shown in FIGS. 4 (b) and 4 (c), and each of them is composed of one byte together with reg0 and reg3. .

Next, the operation of the embodiment having the above-described structure will be specifically described with reference to FIGS. 1, 5, and 6. FIG. 1, 5, and 6 show the CPU 31 of FIG.
5 is a flowchart showing command processing according to the present invention according to the present invention.

This routine starts when the CPU 31 receives a command from the image data processing section and exits from the main routine, and first determines the type of the received command as shown in FIG. And if it is a paper feed selection command, its argument is acquired as shown in FIG.
It is checked whether or not the argument A is valid with a code of 81 hex ≦ A <84 hex. If the argument A is not valid, a rejection code is returned to the image data processing unit 21 and the process returns to the main routine.

If the argument A of the paper feed selection command is valid when 81 hex ≦ A <84 hex, the most significant bit of the argument A is set to “0” and the command register area of the RAM 33 shown in FIG. The data is stored in the register reg1 shown in FIG.

When the argument of the paper feed selection command is an 81 hex code for upper paper feed selection, if the most significant bit is set to "0", the code of 01 hex is stored in the register reg1. Further, in the case of a 82 hex code for selecting lower paper feed, if the most significant bit is set to “0”, the 02 hex code is stored in the register reg1. In addition, 83 he
In the case of the code of x, if the most significant bit is set to “0”, the code of 03 hex is stored in the register reg1.

Register reg in command register area
1 is completed, a tray code indicating the selected paper feed tray (storage paper size) is acquired, and is stored in the register reg3 in the command register area.
Then, the reception code is returned to the image data processing unit 21 and the process returns to the main routine.

If the received command is a paper ejection selection command, the argument is acquired as shown in FIG. 6 and the argument B is 81 hex ≦ B <84 he.
It is checked whether or not the code is valid with the code of x. If the code is not valid, a rejection code is returned to the image data processing unit 21 again.
Return to the main routine. If the argument B of the discharge selection command is valid when 81 hex ≦ B <84 hex, the most significant bit of the argument B is set to “0”, and (b) of FIG.
And then returns the reception code to the image data processing unit 21 and returns to the main routine.

When the argument of the discharge selection command is an 81 hex code for upper discharge selection, setting the most significant bit to "0" stores the 01 hex code in the register reg2. Further, in the case of the 82 hex code for selecting the lower discharge, if the most significant bit is set to “0”, the 02 hex code is stored in the register reg2. In addition, 83 hex for horizontal discharge selection
If the most significant bit is set to "0", a code of 03 hex is stored in the register reg2.

When the received command is a print command stack designation command, the argument is acquired as shown in FIG. 1, and the number of stacks (the number of pages) designated by the argument is shown in FIG. Is set in the stack number setting register (S_REG) shown in FIG.

If the received command is a paper feed start command, the bit 7 of the register reg0 in the command register area is set to "1", and the registers reg0 to reg3 in the command register area are set as one block.
Is transferred to the command buffer area corresponding to another area.
The command buffer area has a capacity capable of storing a plurality of blocks (here, 16 blocks) of registers reg0 to reg3 (4 bytes) as shown in FIG.
The storage address is specified by a storage address pointer (IN_PTR) shown in FIG.

When the transfer to the command buffer area is completed, "4" is added to the storage address of the storage address pointer (IN_PTR) to specify the next block, and then the type of the argument of the received paper feed start command is checked. 81 hex that indicates a forced print command
In this case, the stack number setting register (S_REG) shown in FIG. 4A is reset, the print instruction stack counter (C_FF) is incremented (+1), and then the process returns to the main routine.

If the argument of the paper feed start command is a code of 80 hex indicating a normal print command, the print command stack counter (C_FF) is incremented (+1), and the process returns to the main routine.

Here, when the print control is in a print executable state, the sequence control section 30 prints a stack counter (C_FF) and a stack number setting register (S_R).
EG) when C_FF> S_REG,
Command buffer area storage address pointer (IN_
Printing is started in accordance with the contents of the instruction block specified by (PTR).

Therefore, for example, when “1” is set in the stack number setting register (S_REG), the image data processing unit 21 sends a print start command for two pages (the argument in the paper feed start command is the normal print command). (Instruction) is received, the printing is started, so printing is continuously performed as shown in FIG. 7, and the driving time of the sequence equipment such as the main motor is shorter than that of the intermittent printing shown in FIG. Become.

The embodiment in which the present invention is applied to a laser printer has been described above. However, the present invention is not limited to this, and may be applied to other printers such as LED printers and liquid crystal shutter printers, as well as digital copiers and facsimile machines. It is also applicable to the image forming apparatus of (1).

[0048]

As described above, according to the present invention, a decrease in print duty (a driving time of an image forming process per unit time) due to a delay in processing time in an image data processing unit is prevented. The life of the entire device can be extended.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a process based on a paper feed start command and a print command stack designation command in a command receiving process by a CPU 31 of FIG. 3;

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a laser printer according to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating a schematic configuration of a control unit of the laser printer of FIG. 2;

FIG. 4 is a memory map diagram showing a memory area in a RAM 33 of FIG. 3;

FIG. 5 is a flowchart showing processing based on a paper feed selection command in the command receiving processing by the CPU 31 of FIG. 3;

FIG. 6 is a flowchart showing a process based on a discharge selection command in the command receiving process by the CPU 31 of FIG. 3;

FIG. 7 is a timing chart for explaining the effect of this embodiment.

FIG. 8 is a timing chart for explaining a problem of the conventional image forming apparatus.

[Explanation of symbols]

21 image data processing unit 30 sequence control unit 31 CPU 32 ROM 33 RAM 34 serial I /
O interface 35 Parallel I / O interface

Claims (1)

(57) [Claims] A printing code is converted into image data for laser modulation.
The image data processing unit to be converted and the image creation process operation
A sequence control unit for controlling the image data processing.
The controller prepares one page of laser modulation image data.
Sends a print start command to the sequence control unit.
In the image forming apparatus provided with a communicating means,In the image data processing unit, The print start command is stuck to the sequence control unit.
Send the print instruction stack specification command to specify the number of
A means to communicate,  In the sequence control unit,A print instruction stack designation command is sent from the image data processing unit.
Command is received, the
A stack that sets the number of stacks for
Number setting means, Receives a print start command from the image data processing unit
Check the argument type of the instruction
Print start command checking means From the check result by the means, the print start instruction is issued.
The argument of the command is a code indicating a forced print command and
When it is recognized, the setting by the stack number setting unit is changed.
Setting release means for releasing, Check by the print start command check means
From the result, the argument of the print start command is
If it is recognized as a code indicating a normal print command,
Print start order to stack lint start instruction
Command stack means, The number of stacks of the print start command by this means is
Greater than the number of stacks set by the stack number setting means
If it gets worse, Means for initiating a print operation.
An image forming apparatus characterized in that: