JP2001058450A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of winding jam onto a fixing roller by receiving printing timing information and image information sent out from a printer controller, and controlling a printing sequence of a printer engine based on the printing timing information and the image information. SOLUTION: According to an engine control part comprising various sensors, such as a tip end sensor 16, and a discharged paper sensor 14 for, inputting the information inputted therefrom, a paper feeding operation is started when a printing signal is inputted from a printer controller, and an obliquely feeding roller 15 is stopped temporarily at the time the tip end sensor 16 detects the paper. A vertical synchronizing demand signal is sent out from the engine control part to the printer controller. When a vertical synchronizing signal is outputted from the controller, the obliquely feeding roller 15 is driven again. Thereafter, a main-scanning timing signal produced by receiving an image signal, and a laser beam 3 by a sensor provided immediately before an image writing region is outputted from the printer controller so as to execute the image formation.

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 having a printer unit for controlling a printer engine for executing an electrophotographic process based on an instruction from a printer controller.

[0002]

2. Description of the Related Art FIG. 1 shows a typical image forming apparatus, for example,
FIG. 2 is a cross-sectional view of a main part illustrating a configuration of a laser beam printer.
In FIG. 1, reference numeral 1 denotes a photosensitive drum which is an electrostatic latent image carrier,
Reference numeral 2 denotes a semiconductor laser as a light beam source, 3 denotes a laser beam emitted from the semiconductor laser 2, 4 denotes a polygon mirror for scanning the laser beam 3 on the photosensitive drum 1, and 5 denotes a uniform charging of the photosensitive drum 1. A charging roller, 6 a developing device for developing the electrostatic latent image with toner, 7 a transfer roller for transferring the toner image to paper, 8 a loading cassette for loading paper, and 9 a paper feeder for feeding paper based on a printing request. The paper roller 15 is a skew feeding roller, which corrects skew by transporting the paper while abutting it against a reference surface at the left end (not shown).

Reference numeral 16 denotes a leading edge sensor for detecting the leading edge of a sheet and performing vertical synchronization with a printer controller in accordance with the timing. Reference numeral 11 denotes a fixing roller for fusing the toner transferred to the sheet and fixing the sheet onto the sheet. Reference numeral 12 denotes a sheet discharging roller for discharging the sheet after fixing from the apparatus.
Is a paper discharge sensor for recognizing that the paper has been discharged.

[0004] The printer engine is controlled by a printer controller, and exchanges commands / status and other signals with the printer controller.
The printing is executed by controlling the above-mentioned mechanism.

FIG. 5 is a block diagram showing a control configuration of the image forming apparatus shown in FIG. In FIG. 5, reference numeral 100 denotes a printer controller connected to the printer engine on a one-to-one basis. The printer controller 100 exchanges various signals to be described later with the printer engine, and controls image expansion for converting image code data from a host computer (not shown) into a bitmap signal. An engine control unit 101 performs various mode settings based on command instructions from a printer controller and controls each mechanism control unit described below based on a print request signal.

Reference numeral 102 denotes a paper transport control unit for controlling the driving / stop of a paper transport system (motor, paper feed roller, skew roller). A high-voltage control unit 103 drives / stops each high voltage for charging, development, and transfer based on an instruction from the printer control unit. An optical system control unit 104 drives / stops the scanner motor and adjusts the light amount of the semiconductor laser 2. 105
Reference numeral denotes a sensor input unit for transmitting input information of various sensors such as the leading edge sensor 16 and the paper ejection sensor 14 to the engine control unit 101. An engine control unit 106 controls the temperature of the fixing unit.
A fixing unit temperature control section is performed based on the instruction of the fixing device.

[0007]

In the conventional image forming apparatus constructed as described above, the front margin area is set according to the instruction of the printer controller 100, and the engine control unit cannot control the front margin area.

For this reason, when the leading edge margin area is designated smaller than that in normal printing (zero edge printing), and printing is performed at a high printing ratio such that the leading edge is close to solid black, the paper is transferred from the fixing roller to the paper. There is a problem that it is difficult to separate the two.

As a result, a jam that cannot be easily released by a user has occurred, for example, a sheet that is not separated from the fixing roller wraps around the fixing roller as it is.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus capable of preventing a jam around a fixing roller.

[0011]

An image forming apparatus according to the present invention includes control means for judging image data sent from a connected printer controller and a leading edge write margin, and controlling a print sequence based on these results. I have.

Further, the print sequence control means is configured to set the write margin to be equal to or more than a predetermined value when it is determined that the print ratio for a predetermined period from the leading write position exceeds a predetermined ratio.

Further, the print sequence control means is configured to perform control for determining a write margin based on a print density sent from a connected printer controller.

[0014]

(Embodiment 1) FIG. 1 is a cross-sectional view of a main part of an image forming apparatus showing a typical example of a printer engine to which the present invention is applied. Each of the reference numerals has been described in relation to the related art, and a description thereof will not be repeated.

FIG. 2 is a control block diagram of the printer control device according to the first embodiment of the present invention. In FIG. 2, reference numeral 200A denotes a printer controller, and 201 denotes an engine control unit that sets various modes based on a command instruction from the first printer controller 200A and controls each mechanism control unit described later based on a print request signal. . The engine control unit 201 includes a vertical synchronization control unit 201a and an image information detection unit 201b.

Reference numeral 202 denotes a sheet control unit for controlling driving / stopping of a sheet conveyance system (motor, sheet feeding roller, skew feeding roller). Reference numeral 203 denotes a high-voltage control unit that drives / stops each high voltage for charging, phenomenon, and transfer based on an instruction from the printer control unit. An optical system control unit 204 drives / stops the scanner motor and adjusts the light amount of the semiconductor laser 2. Reference numeral 205 denotes a sensor input unit that transmits input information of various sensors such as the leading edge sensor 16 and the paper ejection sensor 14 to the engine control unit 201. Reference numeral 206 denotes an engine controller 201 for controlling the temperature of the fixing device.
Is a fixing unit temperature control unit performed based on the instruction.

In the thus configured printer control unit, when the / PRNT (print) signal 210 is output from the printer controller, the engine control unit 201
When the leading edge sensor 16 detects a sheet from the start of sheet feeding, the driving of the skew feeding roller 15 is temporarily stopped, and a / VSREQ signal (vertical synchronization request signal) 207 is output to the printer controller 200A. After that, a / VSYNC signal (vertical synchronization signal) 21 is sent from the printer controller 200A.
When 1 is output, the skew feeding roller 15 is driven again. As a result, the writing of the image on the photosensitive drum 1 and the transfer to the paper are synchronized.

The printer controller outputs a / VDO signal (image signal) 212 after a predetermined time has elapsed after outputting the / VSYNC signal. Reference numeral 209 denotes a / BD signal (main scanning timing signal), which is generated by receiving a laser beam 3 emitted from the semiconductor laser 2 and scanned by a sensor (not shown) provided immediately before an image writing area. . / CMD signal 213 is
A is a command sent from A, and a / STS signal 214
Is a status for notifying the printer controller of the state of the engine.

Hereinafter, the vertical synchronization timing control in the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 3 is a timing chart showing the timing of the vertical synchronization timing in the image forming apparatus according to the present invention. Note that T301 to T307 indicate respective timings.

When the / PRNT signal 210 is input from the printer controller 200A, the engine control unit 201 outputs a paper feed command to the paper transport control unit 202 and starts feeding paper from the paper feed cassette 8. Next, the apparatus enters a standby state until the leading edge sensor 16 detects the presence of a sheet. When the presence of a sheet is detected, the skew feeding roller 15 is temporarily stopped to interrupt the sheet conveyance (T301).

Next, the engine control unit 201 outputs a / VSYNCREQ signal (vertical synchronization request signal) to the printer controller 200A (T302). Next, the process waits until the / VSYNC signal 211 is received from the printer controller 200A, and at the same time as receiving the / VSYNC signal, the vertical synchronization control unit 201a sets the timer a
The image information detection unit 201b starts the timer b (T303). Also, the / VSYNCREQ signal is set to Fa.
The state is changed to the 1se state (T305).

The image information detecting section 201b determines the output timing (T304) of the / VDO signal (image signal),
If the lapse of time from 303 is shorter than the predetermined time,
It is determined that zero-edge printing is performed with a small margin at the start of writing, and then while the timer b measures the time t2, / VDO
The time when the signal (image signal) becomes true is counted (T306). When it is determined that the count value exceeds the predetermined value, the engine control unit 201 instructs the vertical synchronization control unit 201a to increase the write margin, and upon receiving this, the vertical synchronization control unit 201a sets the timer a. The time t defined as the time from when the measured value is received after the normal / VSYNC signal is received until the skew feeding roller is restarted.
The skew feeding roller is restarted at a time t3 shorter than 1 (T307).

On the other hand, when the count value of the time when the / VDO signal (image signal) is true at the timing T306 is equal to or smaller than a predetermined value, the normal write margin is set to /
The engine control unit 201 issues an instruction to the vertical synchronization control unit 201a so that the time from receiving the VSYNC signal to restarting the skew feeding roller is t1, and the vertical synchronization control unit 2
01a restarts the skew feeding roller when the value of the timer a reaches t1.

As described above, by judging the image information and the vertical synchronizing signal, it becomes possible to set the margin at the leading end of the writing to an appropriate value for normal conveyance.

(Embodiment 2) FIG. 4 is a timing chart of Embodiment 2 of the present invention. Hereinafter, the vertical synchronization control in the present embodiment will be described with reference to FIG.

When the / PRNT signal 210 is input from the printer controller 200A, the engine control unit 201 outputs a paper feed command to the paper transport control unit 202 and starts feeding paper from the paper feed cassette 8. Next, the apparatus enters a standby state until the leading edge sensor 16 detects the presence of a sheet. When the presence of a sheet is detected, the skew feeding roller 15 is temporarily stopped to interrupt the sheet conveyance (T301).

Next, the engine control unit 201 outputs a / VSYNCREQ signal (vertical synchronization request signal) to the printer controller 200A (T302). Next, the process waits until the / VSYNC signal 211 is received from the printer controller 200A, and at the same time as receiving the / VSYNC signal, the vertical synchronization control unit 201a sets the timer a
The image information detection unit 201b starts the timer b (T303). Also, the / VSYNCREQ signal is set to Fa.
The state is changed to the 1se state (T305).

The image information detector 201b determines the output timing (T304) of the / VDO signal (image signal),
If the lapse of time from 303 is shorter than the predetermined time,
It is determined that zero-edge printing is performed with a small margin at the start of writing, and then while the timer b measures the time t2, / VDO
The time when the signal (image signal) becomes true is counted (T306). When it is determined that the count value exceeds the predetermined value, the engine control unit 201 instructs the vertical synchronization control unit 201a to increase the write margin, and upon receiving this, the vertical synchronization control unit 201a sets the timer a. When the measured value passes the time t from when the / VSYNC signal is received to when the skew feeding roller is restarted, the skew feeding roller is restarted (T308). Here, the drive speed of the transport roller is set to be higher than the normal drive speed, and when the measured value of the timer a reaches t4 (> t1), the speed is returned to the normal speed (T309). Note that it is preferable that the position of the leading end of the sheet at T309 be immediately before entering the photosensitive drum.

On the other hand, when the count value of the time when the / VDO signal (image signal) becomes true at timing T306 is equal to or less than a predetermined value, the time when the skew feeding roller is restarted to make a normal write margin is set. Drive at normal speed.

As described above, by judging the image information and the vertical synchronizing signal, and controlling the paper transport speed from the skew feed roller to the photosensitive drum, it is possible to make the leading margin of the writing start a proper value for normal transport. It becomes possible.

(Embodiment 3) In Embodiment 1, margin control is performed based on image information and vertical synchronization timing.
In this embodiment, the print margin is further controlled based on the density specified by the printer controller.

The printer controller has. The print density is specified to the engine control unit by the CMD signal. The specification of the density can be divided into several steps, and here, it is possible to specify the density in three steps (light, normal, and dark).
The engine control unit controls the developing high pressure of the high pressure control unit based on the designated print density. For example, if the print density is "
When "dark" is designated, the developing high voltage is set to a higher voltage than when the print density is designated "normal".

The writing margin control performed by the engine control unit based on the print density will be described below. The operation from the input of the / PRNT signal 210 from the printer controller 200A to the time T305 when the / VSYNCREQ signal is set to False is the same as in the first embodiment.

The image information detecting section 201b determines the output timing (T304) of the / VDO signal (image signal),
If the lapse of time from 303 is shorter than the predetermined time,
It is determined that zero-edge printing is performed with a small margin at the start of writing, and then while the timer b measures the time t2, / VDO
The time when the signal (image signal) becomes true is counted (T306). The time t2 is variably set by the engine control unit based on the print density specified by the printer controller. t2 is (print density: light)>
(Print density: normal)> (print density: dark).

When it is determined that the count value exceeds the predetermined value K, the engine control unit 201 instructs the vertical synchronization control unit 201a to increase the write margin, and receives the vertical synchronization control unit 201a. Restarts the skew feeding roller when the measured value of the timer a elapses a time t from when the / VSYNC signal is received to when the skew feeding roller is restarted (T308). Next, the measured value of the timer a is t4
(> T1), the speed is returned to the normal speed (T30).
9). The predetermined value K is variably set by the engine control unit based on the print density, similarly to t2. K is
(Print density: light)> (print density: normal)> (print density: dark).

On the other hand, when the count value of the time during which the / VDO signal (image signal) is true at timing T306 is equal to or less than a predetermined value, the time when the skew feeding roller is restarted in order to obtain a normal write margin is set. Drive at normal speed.

Since the density of the toner image formed on the photosensitive drum is changed by changing the resolution, the same control may be performed at this time.

As described above, it is possible to determine the information relating to the toner density, the image information, and the vertical synchronization signal designated by the printer controller, and set the write start margin to an appropriate value for normal conveyance.

[0039]

As described above, according to the present invention,
The image writing margin is controlled by the image information and the vertical synchronization timing information from the connected printer controller, so even if a print with a high printing ratio such as solid black is specified in a situation where the writing margin is small, the fixing roller And the paper can be reliably separated, and the paper jam around the fixing roller can be prevented.

In addition, a further effect can be expected by performing this control based on the print density information.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a configuration of an image forming apparatus to which the present invention is applied.

FIG. 2 is a control block diagram illustrating a printer control device according to the first embodiment of the present invention.

FIG. 3 is a timing chart of signals related to sheet conveyance according to the first embodiment of the present invention.

FIG. 4 is a timing chart of signals related to sheet conveyance according to the second embodiment of the present invention.

FIG. 5 is a control block diagram showing a conventional printer control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Semiconductor laser 3 Laser beam 4 Polygon mirror 5 Charging roller 6 Developing device 7 Transfer roller 8 Loading cassette 9 Feeding roller 15 Skewing roller 11 Fixing roller 12 Discharge roller 14 Discharge sensor 16 Tip sensor 200A Printer controller 201 Engine control unit 201a Vertical synchronization control unit 201b Image information detection unit 202 Paper transport control unit 203 High voltage control unit 204 Optical system control unit 205 Sensor input unit 206 Fixing unit temperature control unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C058 AB18 AC08 AD04 AE02 AE09 AF04 AF18 AF20 GA03 GA07 GA14 GE24 2C061 AQ06 MM14 MM20 MM27 2H027 DA39 DC03 EC10 ED04 ED06 ED17 EE01 EE02 EE03 EE04 FD04

Claims (10)

[Claims] A printer controller for receiving print timing information and image information sent from a connected printer controller, and controlling a print sequence of a printer engine based on both the print timing information and the image information. An image forming apparatus comprising: 2. The printer control section judges an image writing leading edge margin amount from vertical synchronization timing information output from the printer controller and image information from the printer controller, and the margin amount is smaller than a predetermined amount.
2. The control method according to claim 1, wherein when it is determined that the printing ratio for a predetermined period from the leading writing position exceeds a predetermined ratio, control is performed such that a leading margin is larger than a specified amount. Image forming device. 3. The printer control section judges an image writing leading edge margin amount from vertical synchronization timing information output from the printer controller and image information from the printer controller, and the margin amount is smaller than a predetermined amount, and 3. The method according to claim 2, wherein when it is determined that the printing ratio for a certain period of time from the writing position exceeds a predetermined ratio, the paper is sent from a predetermined temporary stop position earlier than a normal paper feeding time. The image forming apparatus as described in the above. 4. The printer control section judges an image writing leading edge margin amount based on vertical synchronization timing information output from the printer controller and image information from the printer controller. 3. The method according to claim 2, wherein when it is determined that the printing ratio for a certain period of time from the writing position exceeds a predetermined ratio, the paper is fed at a speed higher than a normal paper feeding speed from a predetermined pause position. The image forming apparatus as described in the above. 5. The printer control unit according to claim 1, wherein the printer controller determines print density designation information sent from the printer controller, and controls the leading edge write margin based on the designated print density. 3. The image forming apparatus according to 1 or 2. 6. An image forming apparatus comprising: a printer; a printer controller for controlling the printer; and a printer controller for controlling the printer controller in response to an external instruction. A drive / stop unit for driving / stopping the paper transport system; and a leading edge sensor for detecting a leading edge of the paper transported by the paper transport system when the paper transport reaches a predetermined position. When the leading edge sensor detects the leading edge of the sheet, the drive / stop unit stops the paper transport system and requests a vertical synchronization signal to the printer controller. Supplies a vertical synchronizing signal to the printer control unit according to the instruction, and supplies an image signal to the printer control unit according to the instruction. The control unit determines whether the leading edge margin is small at the time interval from the supply time of the vertical synchronization signal to the printer control unit to the output timing of the image signal, and determines the supply time of the vertical synchronization signal to the printer control unit. An image forming apparatus comprising: determining whether a printing ratio is greater than a predetermined amount based on a time when an image signal becomes true; and controlling the paper transport system based on these results. 7. The image forming apparatus according to claim 6, wherein the printer control unit determines that the leading edge margin is small at a time interval from a point in time when the vertical synchronization signal is supplied to the printer control unit to an output timing of the image signal. And the image signal is tru from the time when the vertical synchronizing signal is supplied to the printer control unit.
3. The paper feeding system according to claim 2, wherein when it is determined from the time e that the printing ratio is larger than a predetermined amount, the paper transport system is redriven at an earlier timing than a normal timing to feed the paper at an earlier timing. Image forming apparatus. 8. The image forming apparatus according to claim 6, wherein the printer control unit determines that the leading edge margin is small at a time interval from a point in time when the vertical synchronization signal is supplied to the printer control unit to an output timing of the image signal. And the image signal is tru from the time when the vertical synchronizing signal is supplied to the printer control unit.
When it is determined from the time e that the printing ratio is greater than the predetermined amount, the paper transport system is redriven at a speed higher than the normal paper feeding speed to feed the paper at a speed higher than the paper feeding speed. Image forming device. 9. An image forming apparatus comprising: a printer; a printer controller for controlling the printer; and a printer controller for controlling the printer controller in response to an external instruction. Drive / stop means for driving / stopping the paper transport system; a leading edge sensor for detecting the leading edge of the paper transported by the paper transport system when it reaches a predetermined position; The printer control unit stops the paper transport system by the drive / stop unit when the leading edge sensor detects the leading edge of the paper, and sends a vertical synchronization signal to the printer controller. The printer controller supplies a vertical synchronization signal to the printer control unit in response to a request from the printer control unit, and Supplying an image signal to a printer control unit, wherein the printer control unit determines whether or not the leading edge margin is small at a time interval from the time when the vertical synchronization signal is supplied to the printer control unit to the output timing of the image signal, An image forming apparatus for determining whether the density is high or low from the density determination means, and controlling the paper transport system based on these results. 10. The image forming apparatus according to claim 9, wherein
When the printer control unit determines that the leading edge margin is small at the time interval from the time of supply of the vertical synchronization signal to the printer control unit to the output timing of the image signal, and that the density determination unit determines that the density is high, Re-driving the paper transport system earlier than normal time to feed the paper earlier, or re-driving the paper transport system faster than normal paper feed speed to feed paper faster than paper feed speed An image forming apparatus, wherein the image is sent at a speed.