JPH1148578A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of disturbance or jam of recording image by controlling the carriage of a recording sheet when a contamination occurs on the carrying belt in the way of printing. SOLUTION: A contaminant adhering to a carrying belt is detected by a carrying belt contamination detector 102 and located by means of a control motor 50 for drive roller and a gate array 80d. A PE sensor 103 and the gate array 80d regulated the operation to carry the recording sheet in an uncontaminated region of the carrying belt based on the position of contaminant calculated by means of the control motor 50 for drive roller and the gate array 80d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus such as an ink jet recording apparatus, and controls the conveyance of the conveyance means by detecting the dirt condition of the conveyance means for conveying a recording medium on which an image is recorded. The present invention relates to an image recording apparatus described above.

[0002]

2. Description of the Related Art In general, an ink jet recording apparatus performs recording by discharging ink from a recording head onto a recording sheet as a recording medium.

This ink-jet recording material can easily make the recording head compact, can record a high-definition image at a high speed, has a low running cost, and has a low noise because it is a non-impact method. There is an advantage that a color image can be easily recorded using color inks.

In particular, a full-line type ink jet recording apparatus using a line type recording head having a large number of ejection ports arranged in a width direction orthogonal to the recording sheet conveyance direction can further increase the recording speed. It is.

However, in a full-line type ink jet recording apparatus, the distance from the recording head located at the most upstream side to the recording head located at the most downstream side is considerably long. If the recording sheet is lifted, the recording image may be disturbed or a jam may occur. Therefore, it is necessary to urge the recording sheet downward so that the recording sheet does not rise.

For this purpose, a method is generally used in which a conductive electrode (electrostatic attraction plate) is provided on a platen on which a recording sheet is placed, and a charge is applied to the electrode to generate an electrostatic force to attract the recording sheet. Have been.

In such an ink jet recording apparatus, the recording sheet fed by the sheet feeding device is attracted and held on the upper surface of the conveying belt by the electrodes arranged in the recording area, and is recorded by the recording head while the recording sheet is being recorded. Conveyed by

[0008] In the ink jet recording apparatus configured as described above, while printing, which is image recording, is repeated, ink leakage from the recording head portion or generation and conveyance of mist-like ink (mist) at the time of ink ejection are performed. Ink may adhere to the conveyance belt due to factors such as ink ejection in the absence of paper due to paper jam (jam) in the path.

Further, in addition to the ink stains, the transport belt may be stained by the adhesion of paper dust and dust. In particular, in the case of an ink jet recording apparatus that performs electrostatic attraction as described above, fine dirt such as dust easily adheres to the transport belt, so that belt contamination is more likely to occur than usual.

[0010] Such contamination of the transport belt causes a reduction in the attraction force of the recording sheet to the transport belt, and as a result, the adhesion of the recording sheet to the transport belt deteriorates.

That is, dirt on the conveyor belt has a weak effect on electrostatic attraction for preventing the floating of the recording sheet in the recording area, leading to disturbance of the recorded image and jam.

For this reason, as an ink jet recording apparatus having a belt cleaning processing mechanism for detecting dirt on the conveyor belt and cleaning the same, for example, Japanese Patent Laid-Open No. Hei 5-2866.
And Japanese Patent Application Laid-Open No. 7-228025.

That is, the above-described belt cleaning mechanism has a sensor for detecting dirt on the transport belt and a cleaning roller for removing dirt from the transport belt near the transport belt. And performing a predetermined operation of cleaning the transport belt at an arbitrary timing during printing standby after the sensor detects dirt on the transport belt or when an event for starting the belt cleaning process occurs. It is.

[0014]

However, in the conventional ink jet recording apparatus, even if the sensor detects that dirt on the conveyor belt has occurred during printing, the cleaning of the conveyor belt is performed only after printing is completed. Therefore, there is a problem that the recorded image is disturbed.

If the cleaning process is not automatically performed after the detection of the contamination of the conveyor belt, an event for the user to start the cleaning process by operating the operation panel or the like even after printing is completed. Printing is continuously performed until the error occurs.

For this reason, from the time when the conveyance belt is stained to the time when the cleaning process is actually performed, the conveyance belt is left unclean, and the recording sheet is ideally conveyed during this period. Is no longer something
There has been a problem that the recorded image is likely to be disturbed or jammed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and by controlling the conveyance of a recording medium by controlling the conveyance of a recording medium when the conveyance means becomes dirty during printing.
It is an object of the present invention to provide an image recording apparatus in which disturbance of a recorded image and occurrence of a jam are suppressed.

[0018]

According to another aspect of the present invention, there is provided an image recording apparatus, comprising: a conveying unit for adsorbing and conveying a recording medium; An image recording unit that records an image on a recording medium, and a cleaning unit that cleans the dirt attached to the conveyance unit after recording the image,
The dirt detecting means for detecting dirt during the image recording operation of the transport means, the dirt position interval calculating means for calculating an adjacent dirt position interval from the dirt detected by the dirt detecting means, and the dirt position interval calculating means. A suction adjusting unit that adjusts a suction position based on a stain position interval and the recording medium information so that the recording medium is sucked in a clean area of the transport unit.

According to the second aspect of the present invention, the suction adjusting means adjusts the timing at which the recording medium is sucked in the unclean area of the transport means and the dirt position interval calculated by the dirt position interval calculating means. This is timing adjustment means for adjusting.

According to a third aspect of the present invention, the timing adjusting means detects an end of the recording medium, and the end detecting means detects an end of the recording medium. Transporting standby means for waiting for the transport of the recording medium when the recording medium is transported, so that the recording medium is transported by a portion of the transporting means which is not stained during an image recording operation. The position to be sucked by the means is adjusted in the transport direction.

According to a fourth aspect of the present invention, the timing adjusting means detects an end of the recording medium, and the end detecting means detects an end of the recording medium. And a width adjusting unit for adjusting a position where the recording medium is attracted to the conveying unit in a conveying width direction when the recording medium is conveyed. The position at which the recording medium is attracted to the transport unit is adjusted in the transport width direction so that the recording medium is transported by the location of the transport unit.

[Operation] Based on the above configuration, when the dirt attached to the conveying means is detected by the dirt detecting means,
The dirt position interval of the transporting means is calculated by the dirt position interval calculating means. Then, the recording medium is attracted to the transporting means so as to attract the recording medium in an unstained area of the transporting means based on the dirt position interval calculated by the dirt position interval calculating means and the recording medium information. The position is adjusted by suction adjusting means.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. <First Embodiment> FIG. 1 is a schematic configuration diagram showing an image recording apparatus according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing an enlarged recording sheet feeding portion of FIG. FIG. 3 is a control block diagram of the image recording apparatus.

In FIG. 1, an ink jet recording apparatus 1 as an image recording apparatus having an automatic paper feeder is provided with a paper feed unit 2 for storing recording paper P as a recording medium (recording sheet), and a recording paper P feeder. The image forming apparatus includes a feeding unit 3, a paper discharging unit 4 for discharging the recording paper on which the image is recorded, and a recording head unit 7 as an image recording unit for recording an image on the recording paper P. [Paper Feed Unit] The paper feed unit 2 is a feed rotator that is detachably attached to the base 20 and has a paper feed cassette 23 having a pressure plate 21 on which the recording paper P is loaded, and feeds the recording paper P. This is a configuration including a half-moon-shaped paper feed roller 22.

The pressure plate 21 is rotatably supported by a paper feed cassette 23 about a rotation shaft 21a.
, So as to contact the paper feed roller 22. A separation pad 25 made of a material having a large coefficient of friction, such as artificial leather, for preventing double feeding of the recording paper P is provided on the surface of the pressure plate 21 facing the paper feed roller 22.

Further, a separation claw 26 for separating the recording paper P one by one is provided at a corner on the leading end side of the paper feeding cassette 23 in the recording paper conveying direction. In addition, the base 20 is provided with a release cam (not shown) for releasing the contact between the pressure plate 21 and the paper feed roller 22.

Reference numeral 90 denotes a paper feed roller as a feeding rotating body for manual paper feed.
The recording paper P placed on the paper 1 is fed according to a recording command signal of a computer, and is transported to the transport roller 32.

In the paper feed unit 2 configured as described above,
In the image recording standby state, the release cam pushes the pressure plate 21 down to a predetermined position. In this state, the pressure plate 21 and the paper feed roller 22 are separated.

Thereafter, when the driving force of the transport roller 32 is transmitted to the paper feed roller 22 and the release cam by a gear or the like, the release cam separates from the pressure plate 21.
As a result, the pressure plate 21 rises, and the sheet feeding roller 22 comes into contact with the recording sheet P, so that the recording sheet P is picked up as the sheet feeding roller 22 rotates, and the sheet feeding is started. And
The recording paper P is separated one by one by a separation claw 26 and conveyed to the feeding unit 3. The paper feed roller 22 rotates until the recording paper P is fed to the PE sensor lever 29 of the feeding unit 3, and is again in a standby state in which the recording paper P is separated from the paper feed roller 22, and the driving force from the transport roller 32 is reduced. Will be shut off. [Feeding Unit] The feeding unit 3 includes a transport belt 31 as transporting means for transporting the recording paper P while attracting the recording paper P, and a PE sensor described later. The transport belt 31 includes a driving roller 34,
Conveying roller 32 and pressure roller 35 as driven rollers
It is stretched over. The drive roller 34 is connected to a drive roller control motor 50 via a drive belt 50a as shown in FIG.

A paper pressing member 39 as pressing means for pressing the recording paper P against the conveying belt 31 is attached to the conveying belt 31 around the rotation axis of the pinch roller 33, and is conveyed by urging means (not shown). It is urged toward the belt 31. The paper pressing member 39 is made of a conductive metal plate.

The conveyor belt 31 is about 0.1 mm to 0.1 mm.
This is an endless belt made of a synthetic resin such as polyethylene or polycarbonate with a thickness of about 2 mm. Reference numeral 36 denotes an electrostatic attraction plate serving as an attraction force holding unit held by the platen 30, and is fixed at a position facing the recording head unit 7 with the transport belt 31 interposed therebetween. The electrostatic attraction plate 36 is connected to a high-voltage power supply (not shown) that generates a predetermined high voltage, and applies a voltage of about 0.5 kV to 10 kV to cause the image recording unit of the recording head unit 7 to operate. Is generated on the conveyor belt 31 located at the position (1).

Reference numeral 38 denotes a cleaning roller pair as cleaning means. The cleaning roller pair 38 is disposed so as to sandwich the transport belt 31 and
1 is made of a sponge having a small cell diameter (preferably 10 μm to 30 μm), which can absorb ink to remove stains such as ink attached to 1 and has a small pore diameter (preferably 10 μm to 30 μm) to prevent deterioration in durability. ing.

The transport roller 32 is provided with a pinch roller 33 that rotates in accordance with the rotation of the transport belt 31 so as to abut. The pinch roller 33 is pressed against the conveyor belt 31 by a spring (not shown),
To the recording head unit 7.

Further, an upper guide 27 and a lower guide 28 for guiding the recording paper P are provided at the entrance of the feeding section 3. Further, the upper guide 27 has a PE sensor lever 2 as a transport standby unit for transmitting detection of the leading and trailing edges of the recording paper P to a PE sensor (to be described in detail later) as an edge detecting unit.
9 is attached. Further, a recording head unit 7 that forms an image based on image information is provided downstream of the transport roller 32 in the recording paper transport direction.

In the feeding section 3 configured as described above,
The recording paper P fed to the feeding unit 3 is guided by the upper guide 27 and the lower guide 28 and is transported between the transport roller 32 and the pinch roller 33. At this time, the PE sensor lever 29 detects the leading end of the recording paper P conveyed between the upper guide 27 and the lower guide 28, and thereby obtains the printing position of the recording paper P. Further, the recording paper P is conveyed to the transport belt 31 via the transport roller 32 by the ultrasonic motor.
Is conveyed by rotating. [Recording Head Unit] The recording head unit 7 of this embodiment uses a line type ink jet recording head in which a plurality of nozzles are arranged in a width direction orthogonal to the conveying direction of the recording paper P. From the upstream side in the direction, a black recording head 7K, a cyan recording head 7C, a magenta recording head 7M, and a yellow recording head 7Y are arranged at predetermined intervals. Then, these color recording heads 7
K, 7C, 7M, 7Y are attached to the head holder 7d. These color recording heads 7K, 7C, 7M,
7Y is a structure capable of heating the ink by a heater or the like. Then, the ink causes film boiling by the heater,
Ink is ejected from the nozzles 7a of the recording head unit 7 by a pressure change based on the growth or contraction of bubbles due to the film boiling, and an image is formed on the recording paper P.

One end of the recording head unit 7 is rotatably supported by a shaft 7b, a projection 7c formed at the other end is engaged with a rail 7e, and the distance between the nozzle 7a and the recording paper P ( Paper interval). [Discharge Unit] The discharge unit 4 includes a discharge roller 41 and a spur 42, and the recording sheet P on which an image is formed by the image recording unit is nipped and conveyed by the discharge roller 41 and the spur 42. And is discharged to the discharge tray 43.

Next, the operation will be described.

The recording paper P is guided to the recording head 7 while being pinched by the pinch roller 33 and the transport belt 31 around which the transport roller 32 is wound. The recording paper P is transported to the transport belt 31 corresponding to the electrostatic attraction plate 36 in a state where the recording paper P is pressed against the transport belt 31 by the paper pressing member 39, and the transport belt is transported by the attraction force given from the electrostatic attraction plate 36. 31 is adsorbed on the flat surface portion.

Then, while being printed by the recording head unit 7, the sheet is fed in the direction of arrow X by the drive roller 34 via the drive roller control motor 50. At this time, the conveying belt 31 does not have a member that protrudes toward the recording head unit 7 even when recording the leading and trailing end portions of the recording paper P. Recording can be performed while approaching the end of P, and a recorded image with high accuracy can be obtained.

When a large amount of ink is ejected on the recording paper P, the recording paper P swells, and a wavy (cockling) occurs. Also in this case, the recording paper P is attracted to the transport belt 31 by the attraction force of the electrostatic attraction plate 36 and the pressing force of the paper pressing member 39, so that the recording paper P does not rise to the recording head unit 7 side. Therefore, the recording head unit 7
And the recording paper P is not in contact with each other, and a stable recorded image can be obtained.

Further, even when the end of the recording paper P is wavy or curled due to a change in environment such as temperature and humidity, the recording paper P is pressed against the transport belt 31 by the paper pressing member 39. In addition, it is possible to suction-transport onto the conveyance belt 31 corresponding to the electrostatic suction plate 36 in a state where waving and curling are removed. Therefore, the recording material P can be stably adsorbed in the recording head unit 7.

FIG. 3 is a block diagram showing a control unit of the ink jet recording apparatus according to the present invention and a configuration of a device controlled by the control unit.

Reference numeral 100 denotes a cleaning roller pair control solenoid for controlling the contact and separation of the cleaning roller pair 38 with the conveyance belt 31 interposed therebetween; 101, a feed roller control motor for controlling the feed roller 22; A driving roller control motor as a dirt position calculating means for controlling the driving roller 34 for performing the cleaning, a conveying belt dirt detecting sensor as a dirt detecting means for detecting dirt on the conveying belt 31, and a recording paper P PE sensor as an end detecting means for detecting the conveying end of
It is connected to the E sensor lever 29.

The control unit 80 includes a CPU 8 as control means.
0a, a ROM 80b for storing programs, a work memory 80c required for control, and a gate array 80d as adjustment means, all of which are connected via a system bus.

The gate array 80d is provided with control signals for the drive roller control motor 50 and the paper feed roller control motor 101 and the cleaning roller pair control solenoid 100.
Control signal, an image signal to the recording head unit 7, a control signal for the recording head unit 7, and a sensor 1
02 and the information from the PE sensor 103 are read.

The sensor 102 for detecting contamination of the conveyor belt such as an optical sensor is not shown in FIGS. 1 and 2, but is provided on the surface of the conveyor belt 31 between the conveyor roller 32 and the pressure roller 35. It is arranged.

FIGS. 4 to 7 are flowcharts for controlling the ink jet recording apparatus according to the present invention.

FIG. 4 is a flowchart showing a process for detecting contamination of the conveyor belt 31. FIG. 5 is a flowchart illustrating a process of feeding the recording sheet P to the transport belt 31. FIG. 6 is a flowchart illustrating the cleaning process for cleaning the conveyance belt 31. FIG. 7 shows the conveyor belt 31.
10 is a flowchart showing a belt position management process for managing the number of steps from a belt reference position to specify the current position of the belt.

A program corresponding to the processing shown in these flowcharts is recorded in the ROM 80b, and is read and executed by the CPU 80a.

Subsequently, a control method of the ink jet recording apparatus according to the present embodiment will be described with reference to flowcharts of FIGS.

First, the process of detecting the contamination of the conveyor belt 31 shown in the flowchart of FIG. 4 is periodically called by an interruption event at a predetermined interval during the printing operation during the image recording operation. By the step S1, the transport belt 31
Conveyor belt dirt detection sensor 102 provided on the surface of
Get information from. In the present embodiment, the surface state of the conveyor belt 31 having the entire belt width is obtained as a density pattern at a time by using an optical sensor capable of reading a line-type pattern. Then, by examining the density change of the acquired density pattern, it is determined whether or not the transport belt 31 is contaminated (step S2). Here, if no change in density is observed, it is determined that belt contamination has not occurred, and the belt contamination detection processing of this flowchart is terminated.

When it is determined in step S2 that the belt has been soiled, the current soil position of the conveyor belt 31 is immediately obtained (step S3). This belt dirt position can be detected by the count number counted by the ultrasonic motor which is the drive roller control motor 50 monitored by the belt position management processing shown in the flowchart of FIG.

The RAM 80c records and stores the acquired belt dirt position in a belt dirt information management table as shown in FIG. 8, but prior to that, the dirt information of the same belt position is already recorded in the belt dirt information management table. It is determined whether or not there is (step S4).

The belt contamination information management table includes a record number, a belt contamination position, and a belt contamination level, and is additionally updated each time belt contamination is detected. However, in the present embodiment, the belt dirt level is not used.

If the stain information of the same belt position is recorded in the belt stain information management table, the belt stain information of the record is updated to the belt stain information just obtained (step S5). If the stain information of the same belt position is not recorded in the belt stain information management table, a new record is added and the acquired belt stain position is recorded (step S6).

Finally, a flag indicating the presence or absence of dirt on the conveyor belt 31 is set (step S7), and the processing ends.

The paper feed control process shown in the flowchart of FIG.
Called when the paper feeding phase is reached. First, the recording paper P is fed to the position of the PE sensor 103 immediately before the conveyance belt 31 by rotating the paper supply roller 22 by the paper supply roller control motor 101 in step S10.

Here, the state of the flag indicating the presence or absence of belt contamination managed by the belt contamination detection process shown in the flowchart of FIG. 4 and the cleaning process shown in the flowchart of FIG. 6 is determined (step S11).

If the flag is clear without belt dirt, there is no dirt on the conveyor belt 31, and the recording paper P standing by at the position of the PE sensor 103 is left as it is.
Is supplied to the transport roller 32 and is stacked on the transport belt 31 (step S19), and the paper feed control process is completed.

When the flag is set to the belt dirt, it indicates that the belt dirt has been generated by the belt dirt detection processing shown in the flowchart of FIG. 4, and the processing subsequent to step S12 is performed. That is, first, a belt dirt information management table stored in the RAM 80c is read (step S12), and belt dirt positions included in a plurality of records recorded in the belt dirt information management table are totaled and analyzed (step S12). S13).

Here, first, in order to make it easy to understand the positional relationship of each dirt on the transport belt 31, the dirt is sorted in ascending order by the number of motor steps from the belt dirt position, that is, the reference position of the transport belt 31. Then, a dirt interval (dirt position interval) is calculated from the difference in the number of steps between one dirt position of the transport belt 31 and the belt dirt position of an adjacent record. Here, since the rotation angle of the motor in one step is constant, the amount by which the transport belt 31 advances is also predetermined by the configuration of the feeding unit 3 shown in FIG.

Next, in step S10, the PE sensor 1
Recording paper P fed to position 03 and waiting
The recording sheet information such as the size and orientation of the recording sheet is acquired (step S14). This recording sheet information is recorded on the recording paper P
Is provided on a paper feed cassette or a manual feed tray on which is loaded, and is acquired by the state of a guide sensor (not shown).
Then, the determination means determines that the recording sheet information and the conveyance belt 31
It is determined whether or not the dirt position interval of the conveyor belt 31 is equal to or longer than the length of the recording paper P based on the dirt position intervals (step S15).

If the dirt position interval is not longer than the length of the recording paper P, the recording paper P that has been fed to the position of the PE sensor 103 is supplied to the transport roller 32 and is fed to the transport belt 31 as it is (see FIG. 4). Step S19).
In this case, since the position where the recording paper P is stacked is not adjusted, an image is recorded on the recording paper P while the surface state of the transport belt 31 is undefined.

If the dirt position interval is equal to or longer than the length of the recording paper P, first, the current position of the conveyor belt 31 is obtained (step S16), and then the recording paper P is fed to this position. Is determined (step S17). This timing is represented by the number of steps required until the top of the clean area of the transport belt 31 reaches the position sandwiched between the transport roller 32 and the pinch roller 33. The number of steps is the current position of the conveyor belt 31,
In other words, it is calculated based on the number of steps from the belt reference position, the leading position of the clean area of the conveyor belt 31 and the predetermined total length of the conveyor belt 31. Here, for simplicity of explanation, the recording paper P
Is very small and is negligible until it is supplied from the position of the PE sensor 103 to the transport roller 32.

After waiting until the timing determined by the timing adjusting means (step S18), P
The recording paper P at the position of the E sensor
And is fed to the conveyor belt 31 (step S19). By the procedure for adjusting the paper feed timing, the recording paper P is fed to an optimum position free from belt contamination.

The cleaning process shown in the flowchart of FIG. 6 is called by operating an operation panel (not shown) provided in the ink jet recording apparatus in a predetermined procedure.

First, in step S31, the transport belt 3
1 is performed. Under the control of the cleaning roller control solenoid 100, the cleaning roller pair 38 is brought into close contact with the conveyance belt 31 therebetween. In this state, the drive roller control motor 50 is controlled to rotate the conveyor belt 31 by the entire length of the belt, thereby making the conveyor belt 3
1 is entirely cleaned.

When the cleaning of the transport belt 31 is completed, all the contents of the belt dirt information management table recorded and stored by the belt dirt detection process shown in the flowchart of FIG. 4 are discarded (step S32), and the belt dirt detection process is performed. Clears the flag indicating the presence or absence of the belt dirt set in step S33 (step S33). According to this procedure, each data referred to in the paper feed control process shown in the flowchart of FIG. 5 is initialized.

The belt position management process shown in the flowchart of FIG. 7 is called every time the drive roller control motor 50 is driven by one step.

First, in step S41, the transport belt 3
Detection of one reference position is performed. At this time, the reference position of the conveyor belt 31 is detected by using a conveyor belt dirt detection sensor 102 provided for detecting belt dirt, and a belt reference position previously marked at one position of the conveyor belt 31 is used. The detection mark pattern is detected.

In the present embodiment, a solid line of a specific color drawn in the belt width direction is drawn so that the belt reference position detecting mark pattern can be easily recognized as a belt stain due to ink or the like even when the mark pattern is detected by the optical sensor. It is a mark for detecting the belt reference position. Then, based on the detected information, it is determined whether or not the current position of the conveyor belt 31 is a belt reference position (step S42). This determination is simply made by comparing the belt reference position detection mark pattern prepared in advance with the detected information, that is, the read pattern.

If the current position is determined to be the belt reference position by the above determination, the step counter indicating the driving amount of the drive roller control motor 50 from the belt reference position is reset (step S43).

If it is determined that the position is not the belt reference position, the step counter is incremented and the driving amount is counted.

As described above, the means for determining the specific position of the conveyor belt 31 is provided, and the deviation amount from the sensor position is constantly managed and held. The position of belt contamination can be specified. <Second Embodiment> In the first embodiment, the paper feed position in the transport direction is adjusted by adjusting the timing at which the recording paper P is fed to the transport rollers 32 to adjust the recording paper P. Is prevented from being loaded on the belt dirt position.

On the other hand, when the width of the transport belt 31 is sufficiently large relative to the width of the recording paper P to be fed, as in the present embodiment, the width of the transport roller 32 is adjusted by the width adjusting means. The recording paper P to be fed or the transport belt 31 can be moved in the transport width direction to prevent the recording paper P from being stacked at the belt dirt position. In addition,
In this case, the width adjusting means moves the conveyance roller 32, the drive roller 34, and the pressure roller 35 in the width direction to shift the conveyance position of the recording material P adsorbed to the conveyance belt 31 in the width direction, or 90, the feeding position of the recording material P is shifted.

With this configuration, the transport belt 3
1 to avoid the belt contamination in the width direction of the recording paper P
Can be stacked, so that even when printing a plurality of pages continuously, the interval between the recording sheets P can be kept at the shortest distance. Therefore, the present embodiment is effective for high-speed continuous sheet feeding. <Third Embodiment> In the first embodiment, a line type optical sensor is used as a means for detecting belt contamination, but the present invention is not limited to this.

In other words, the dirt may be detected by scanning in the width direction of the conveyor belt 31 using a serial type sensor, or a plurality of sensors may be arranged in the width direction of the conveyor belt 31. May be used to detect the contamination of the entire conveyor belt 31.

Further, the conveyor belt 31 may be damaged due to belt contamination.
The decrease in the adsorption force of the ink is caused by the undried ink with moisture remaining. Therefore, when the ink is sufficiently dried, the occurrence of belt contamination can be ignored. For this reason, it is possible to detect belt contamination by a sensor that detects moisture or moisture instead of the optical sensor.

In this case, belt contamination which does not hinder the suction conveyance can be ignored, so that it is more efficient. Fourth Embodiment In the first embodiment, the reference position of the belt is detected by detecting a pattern previously marked on the transport belt 31 by an optical sensor. However, the present invention is not limited to this.

That is, a protrusion is provided at a specific portion of the conveyor belt 31, and a member that operates in the same manner as the PE sensor lever 29 and a sensor or switch that operates in conjunction with the member are provided on the protrusion forming surface of the conveyor belt 31. Good. By doing so, a sensor or a switch reacts by the contact between the projection on the conveyor belt 31 and the lever equivalent member, and the reference position of the conveyor belt 31 can be detected. <Fifth Embodiment> In the first embodiment, the recording paper P is configured to be stacked while avoiding any belt dirt generated on the transport belt 31. It is not limited to this.

When the belt dirt is very small, the attraction force of the conveyor belt 31 does not extremely decrease. For this reason, practically, it is not necessary to avoid all the belt dirt. Therefore, not only the determination of the interval between each belt dirt position as in the first embodiment, but also the state of the belt dirt in the peripheral area is considered. Make a decision.

More specifically, when analyzing the belt dirt information management table created by the belt dirt detection process shown in the flowchart of FIG. 4, one belt dirt position as shown in the conversion flow of FIG. , And averages the belt dirt levels of the n blocks around the focused belt dirt position (point of interest). This operation is repeated for all belt dirt positions to smooth the belt dirt level. Further, the smoothed belt dirt level is compared with a threshold value represented by a previously prepared adsorption limit dirt level, and the belt dirt state at each position is re-expressed as a digital value. In the case of FIG. 9, 0 represents a state without dirt, and 1 represents a state with dirt. By determining an area free from belt contamination based on the table created in this way and taking into account the degree of contamination including the peripheral area, the transport belt surface can be used more effectively. <Sixth Embodiment> In the first embodiment, the processing is not changed depending on the type of the recording paper P, and the determination is made only on the contamination state of the transport belt 31, but the present invention is not limited to this. It is not something to be done.

The force by which the recording paper P is attracted to the conveyor belt 31 by electrostatic attraction varies depending on factors such as the material and thickness of the recording paper P. For this reason, there are some types of recording paper P that are easily adsorbed and those that are hardly adsorbed depending on the material type. For example, it has been found that thick postcards are less likely to be adsorbed than plain paper, but that thin OHP sheets made of celluloid are easily adsorbed.

In consideration of this, by changing the threshold value for digitizing the belt dirt level depending on the type of the recording paper P, or by adjusting the number of blocks around the target point for smoothing, various recording papers can be used. It is possible to make an optimal determination for the type of P.

The type of recording sheet can be designated by the user at the start of printing from an operation panel provided in the ink jet recording apparatus.

In the above-described embodiment, as the suction adjusting means, the timing is adjusted so that the recording material P is sucked in the unclean area of the transport belt 31, but the suction position may be adjusted. Of course, the same effects as those of the above-described embodiment can be obtained.

[0087]

As is apparent from the above description, according to the present invention, dirt adhering to the conveying means is detected by the dirt detecting means, and the dirt position of the conveying means at this time is calculated by the dirt position calculating means. At the same time, the suction position adjusting means sucks the recording medium so as to convey the recording medium in an unstained area of the conveying means based on the dirt position interval calculated by the dirt position calculating means and the recording medium information, and records the image. Since the adjustment is performed, it is possible to suppress the disturbance of the image recording on the recording medium and the occurrence of the jam until the cleaning process of the conveying unit is performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an image recording apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a recording sheet feeding portion of FIG. 1 in an enlarged manner.

FIG. 3 is a control block diagram of the image recording apparatus.

FIG. 4 is a flowchart illustrating belt contamination detection processing according to the first embodiment of the image recording apparatus of the present invention.

FIG. 5 is a flowchart illustrating a sheet feeding control process according to the first embodiment of the image recording apparatus of the present invention.

FIG. 6 is a flowchart illustrating a cleaning process according to the first embodiment of the image recording apparatus of the present invention.

FIG. 7 is a flowchart illustrating a belt position management process according to the first embodiment of the image recording apparatus of the present invention.

FIG. 8 is a diagram illustrating a configuration of a belt contamination information management table according to the first embodiment of the image recording apparatus of the present invention.

FIG. 9 is a diagram showing a belt dirt information conversion flow according to the first embodiment of the image recording apparatus of the present invention.

[Explanation of symbols]

29 Conveying standby unit (PE sensor lever) 31 Conveying unit (conveying belt) 32 Conveying unit (conveying roller) 38 Cleaning unit (cleaning roller pair) 50 Dirt position interval calculating unit (drive roller control motor) 80d Gate array 102 Dirt detection Means (Conveyor belt dirt detection sensor) 103 Edge detection means (PE sensor)

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI G01N 21/89 B41J 3/04 101Z

Claims (4)

[Claims] A conveying means for adsorbing and conveying a recording medium;
An image recording apparatus comprising: an image recording unit configured to record an image on a recording medium sucked and transported by the transporting unit; and a cleaning unit configured to clean dirt attached to the transporting unit after image recording. A dirt detecting means for detecting dirt during operation; a dirt position interval calculating means for calculating an adjacent dirt position interval from dirt detected by the dirt detecting means; a dirt position interval calculated by the dirt position interval calculating means; An image recording apparatus, comprising: a suction adjusting unit that adjusts a suction position so that the recording medium is sucked in a clean area of the conveyance unit based on recording medium information. 2. The suction adjusting device according to claim 1, wherein the suction adjusting device adjusts a timing at which the recording medium is sucked in a non-dirty area of the transporting device and a dirt position interval calculated by the dirt position interval calculating device. The image recording apparatus according to claim 1, wherein: 3. The recording medium according to claim 1, wherein the timing adjustment unit detects an end of the recording medium, and detects the end of the recording medium when the end detection unit detects the end of the recording medium. A conveyance standby unit for waiting for conveyance, and conveying the recording medium at a position where the recording medium is attracted to the conveyance unit so that the recording medium is conveyed by a portion of the conveyance unit that is clean during an image recording operation. The image recording apparatus according to claim 2, wherein the direction is adjusted. 4. The recording medium according to claim 1, wherein the timing adjustment unit detects an end of the recording medium, and detects the end of the recording medium when the end detection unit detects the end of the recording medium. A conveyance standby unit that waits for conveyance, and a width adjustment unit that adjusts a position where the recording medium is attracted to the conveyance unit in a conveyance width direction. The image recording apparatus according to claim 2, wherein a position at which the recording medium is attracted to the conveyance unit is adjusted in a conveyance width direction so that the recording medium is conveyed.