JPH06218914A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain printing which is free from oblique motion even though long continuous printing is carried out by a method wherein a transfer means having a plurality of divided parts and a means which applies pressure to each of a plurality part divided according to a recording density distribution of a recording image are provided. CONSTITUTION:Upper and lower stream side paper feed rollers 27, 28 are respectively divided into three rollers of left side positioned paper presser pressure variable rollers R1, R4, central part positioned paper presser pressure variable rollers R2, R5, and right side positioned paper presser pressure variable rollers R3, R6 A controller 41 of a printer receives a recording data and a density distribution data of a recording band from a scanner 1. The received density distribution data is judged. When the left side is thick in density in all of the bands, paper presser pressure of the left end part rollers R1, R4 are set slightly higher. When the right side is thick, paper presser pressure of the right end part rollers R3, R6 are set slightly higher. When all is uniform, paper presser pressure is set same for the right end part, the central part, and the left end part to carry out recording and paper feeding. This procedure is carried out for each band recording until the recording is ended.

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 copying machine, and more particularly to an image forming apparatus capable of using recording sheets of various sizes.

[0002]

2. Description of the Related Art A full-color image forming apparatus equipped with an ink jet recording apparatus utilizing the film boiling phenomenon is widely used. Such a device, for example, a color copying machine, does not have a single size as a recording sheet, but various types of sheets having different sizes are used.

For example, in an ink jet type full-color copying machine capable of making a large-sized copy, not only a large-sized copy at the same size but also a roll paper as a recording paper in addition to its enlargement function, and a serial scan system are used. Since the recording is performed in (1), it is possible to perform long continuous recording exceeding the maximum size of 1 ×.

However, in the conventional apparatus, since the pressure of the paper pressing in the paper feeding roller portion can be uniformly kept at a constant value, when there is a density unevenness in a long continuous recording image, the paper feeding amount has a deviation. As a result, the paper skewed, and it was not possible to carry out extremely long continuous recording, for example, exceeding 10 m.

Further, in this type of device, air is sucked from the inside of the platen and the negative pressure causes the recording paper to be sucked onto the platen. The area of the platen for sucking air is fixedly divided according to the size of the paper, and there is no air leakage during suction.

However, in the conventional apparatus, in the case of a recording sheet having a size other than the size set in the image forming apparatus, a so-called non-standard recording sheet, etc., an air leak, a suction failure at the end of the recording sheet, etc. May occur. When an image is formed in such a state, there is a drawback that the recording head catches the recording paper and the recording head and the recording paper are damaged. Further, there is also a drawback that the size of the recording paper is limited for the above reason.

[0007]

SUMMARY OF THE INVENTION The present invention prevents the above-mentioned conventional drawbacks, namely, skewing of the recording sheet due to uneven recording density and suction failure due to air leakage of the platen, and various recording sheets of various sizes. An object is to provide an image forming apparatus capable of performing stable recording.

[0008]

In order to achieve the above-mentioned object, an image forming apparatus according to the present invention is a recording head for ejecting ink to perform recording on a recording medium, pressing the recording medium and recording the recording medium. A means for transporting the recording medium in a direction orthogonal to the scanning direction of the head, the transporting means having a plurality of divided portions, and the divided portions according to the recording density distribution of the recorded image, respectively. It is characterized by having means for individually applying pressure.

Here, the transfer means may be a paper feed roller, and may have means for detecting the recording density distribution of the image recorded on the recording medium.

Further, the image forming apparatus according to the present invention comprises a recording head for ejecting ink to record on a recording medium, a hollow recording medium placing means having a suction hole for sucking the recording medium, Suction means for sucking air inside the placing means, means for detecting the pressure inside the placing means,
And a means for continuously changing the suction area of the placing means.

The image forming apparatus may be a copying machine, or the recording head may be an ink jet recording head which discharges ink by utilizing a liquid boiling phenomenon.

[0012]

In the present invention, means for dividing the paper feed roller portion so that the pressure of the paper presser can be individually changed and adjusting the pressure of the paper presser according to the density distribution of the image area to be recorded is provided. By providing the recording paper, recording can be continuously performed as long as the paper continues without causing skew.

Further, according to the present invention, by providing the means for dynamically changing the air suction area in the platen according to the size of the recording sheet and the means for detecting the suction pressure, the recording of any size can be performed. Even a sheet of paper can be completely adsorbed and does not cause an adsorption failure due to a change in the size of the recording paper.

[0014]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 is an external view of a digital color copying machine to which the present invention is applied. The whole can be divided into two parts. The upper part of FIG. 1 is a color image scanner unit 1 that reads a document image and outputs digital color image data, and is incorporated in the scanner unit 1 to perform various kinds of image processing of digital color image data and to interface with external devices. The controller unit 2 having the processing function of

The scanner unit 1 reads a three-dimensional object or sheet original placed below the original pressing member 11.

The operation unit 10 is connected to the controller unit 2 and is used to input various information as a copying machine. The controller unit 2 gives an operation instruction to the scanner unit 1 and the printer unit 3 according to the input information. When it is necessary to perform more complicated edit processing, a digitizer or the like is attached in place of the document pressing member 11 and connected to the controller unit 2 to enable high-level processing.

The lower part of FIG. 1 shows a printer section 3 for recording a color digital image signal output from the controller section 2 on a recording sheet. In this embodiment, the printer unit 3
Is a full-color inkjet printer using a recording head of the inkjet recording system described in JP-A-54-59936.

The two parts described above are separable, and it is possible to install them at separate places by extending the connecting cable.

In the present invention, the printer unit 3 according to the present invention
Operation will be described, and detailed description of the scanner unit 1 will be omitted.

FIG. 2 is a side sectional view of the digital color copying machine of FIG.

First, an exposure lamp 14, a lens 15, and an image of a document placed on a platen glass 17 by an image sensor 16 (a CCD in this embodiment) capable of reading a line image in full color, a projected image by a projector or a sheet. The sheet original image is read by the feeding mechanism 12. Next, various image processings are performed by the scanner unit 1 and the controller unit 2 to record on a recording sheet.

In FIG. 2, the recording paper is a paper feed cassette 20 for storing cut sheets of small size (up to A3 size in this embodiment) and large size (maximum, A1 size or larger) recording. It is supplied from roll paper 29. Further, as for paper feeding, by inserting the recording paper one by one from the manual feeding port 22 of FIG. 1 along the paper feeding cover 21, it is possible to feed paper from the outside of the apparatus (manual paper feeding). The recording paper does not have to be of a fixed size (A version, B version, etc.).

The pick-up roller 24 is a roller for feeding cut sheets one by one from the sheet feeding cassette 20, and the fed cut sheets are fed by the cut sheet feeding roller 25 to the first feeding roller 26. Be transported to.

The roll paper 29 is a roll paper feed roller 30.
Is sent out by the cutter, cut into a fixed length by the cutter 31, and conveyed to the paper feed first roller 26.

Similarly, the recording sheet inserted through the manual feed port 22 is conveyed by the manual feed roller 32 to the first paper feed roller 26.

The pick-up roller 24, the cut paper feed roller 25, the roll paper feed roller 30, the first paper feed roller 26, and the manual feed roller 32 are a feed motor (not shown) (in this embodiment, a DC servo motor). The on-off control can be performed at any time by the electromagnetic clutch attached to each roller.

When the printing operation is started by an instruction from the controller unit 2, the recording sheet selected and fed from any one of the above-mentioned sheet feeding paths is conveyed to the sheet feeding first roller 26. In order to remove the skew of the recording sheet, the sheet feeding first roller 26 is turned on and the recording sheet is conveyed to the sheet feeding second roller 27 after forming a predetermined amount of paper loop.

Between the paper feed first roller 26 and the paper feed second roller (upstream side roller) 27, an accurate paper feed operation is performed between the paper feed roller (downstream roller) 28 and the paper feed second roller 27. To do this, a predetermined amount of recording paper is slackened to form a buffer. The buffer amount detection sensor 33 is a sensor for detecting the buffer amount. By constantly forming the buffer during the paper conveyance, it is possible to reduce the load applied to the paper feed roller 28 and the second paper feed second roller 27, especially when the large-sized recording paper is conveyed, and the accurate paper feed operation is possible. Become.

When printing with the recording head 37,
The scanning carriage 34, on which the recording head 37 and the like are mounted, reciprocally scans on the carriage rail 36 by the scanning motor 35. Then, the image is printed on the recording paper in the forward scan, and the recording paper is fed by the predetermined amount by the paper feed roller 28 in the backward scan. At this time, the drive system is driven by the paper feed motor to detect the buffer amount sensor 33.
The control is performed so that the predetermined buffer amount is always obtained while being detected by.

The printed recording paper is output to the discharge tray 2
Then, the printing operation is completed.

In this embodiment, the recording head 37 is the ink jet nozzle of the above-mentioned system, and the nozzle having 256 nozzles assembled in each of Y, M, C and K is used.
I'm using a book.

[Embodiment 1] FIG. 3 shows an outline of the paper feeding / recording portion of the printer unit of the first embodiment. In this embodiment, roll paper 29 is used as the recording paper. In the figure, reference numeral 41 is a control / calculation device, 42 is a recording head drive device, 43 is a paper feed roller motor located upstream of the printing paper, 44 is a paper feed roller motor located downstream of the printing paper, and 45 Is a communication cable for exchanging data with the scanner. The upstream and downstream paper feed rollers 27 and 28 are each divided into three parts. That is, the former is a roller R _{1 at} the left end of the paper feed roller that can change the pressure of the paper presser, a roller R _{2 at} the center of the paper feed roller that can change the pressure of the paper presser, and a right end of the paper feed roller. The roller R _{3 of} which the pressure of the paper retainer is positioned is the roller R ₃ whose latter is the roller R of which the pressure of the paper retainer is variable at the left end of the downstream paper feed roller.
₄ , the roller R ₅ is located at the center of the paper feed roller and has a variable paper pressing pressure, and the roller R ₆ is located at the right end of the paper feed roller and has a variable paper pressing pressure. R
P ₁ is a roller presser pressure adjuster for R ₁ , RP ₂ is a roller presser pressure adjuster for R ₂ , R ₃ is a roller presser pressure adjuster for R ₃ , and RP ₄ is a roller presser pressure adjuster for R _4. Machine, RP ₅ is a roller presser pressure control device for roller R ₅ , P
R ₆ is a paper pressing pressure adjusting device for the roller R ₆ .

Prior to the image recording operation on the recording paper, the scanning carriage 34 is moved to the home position, then the forward scan is performed in the direction of arrow A, and cyan C, magenta M, and yellow Y from a predetermined position. , Black BK ink is ejected from the recording head 37 to perform image recording. When the image recording for a predetermined length is completed, the scanning carriage 34 is stopped, and conversely, backward scanning is started in the direction of arrow B,
The scanning carriage 34 is returned to the position. After recording one line, the paper is fed by the length of the print head 37 in the direction of arrow C by driving the paper feed motors 43 and 44 and the paper feed rollers 27 and 28.

FIG. 4 shows an operation flow chart of this embodiment. The operation will be described with reference to FIG. In step S1, the control device 41 of the printer receives the print data from the scanner 1 and also receives the density distribution data of the band to be printed as shown in FIG. The received density distribution data is judged in step S2. If the left side is dark in the entire band, the process proceeds to step S3, and the paper pressing pressure of the left end roller is set to be high, and if the right side is dark, step S3 is performed.
In step S5, the paper pressing pressure of the right end roller is set to a high value, and if the whole is uniform, the paper pressing pressure is set in step S6 at the right end, the center, and the left end as well, and recording and paper feeding are performed. I do. By performing this for the recording of each band until the end of recording, it is possible to suppress the skew of the recording sheet caused by the deviation of the recording density, and it is possible to perform long continuous recording using roll paper.

[Embodiment 2] FIG. 6 shows a structure of a carriage portion according to a second embodiment of the present invention.

Reference numeral 46 is a reading sensor capable of reading the entire recording width, and 47 is a lamp for illuminating the image area read by the reading sensor 46.

FIG. 7 shows an operation flow chart of this embodiment. The operation will be described with reference to FIG. First of all, step S
In 11, the paper pressing pressure is recorded with the default value. Recording is performed and the area recorded in step S12 is read by the sensor 46. The sensor 46 need not have the same resolution as the recording density as long as the inclination of the density of the entire recorded band can be determined. Therefore, a sensor that is inexpensive and detects a wide range is used. In step S13, the density distribution of the band recorded by the output of the sensor 46 is obtained by calculation. Before performing the paper feed, to determine the resultant density distribution at step S14, by increasing the value of RP ₁ proceeds to step S15 if darker the left end, if darker right end portion proceeds from step S16 to step S17 of RP ₃ The adjustment value is changed, the pressure of the paper presser is adjusted, and the paper is fed in step S18. If the density is uniform, the process proceeds from step S16 to S18. Continuous recording is performed by repeating the above process. As a result, it is only necessary to use an inexpensive sensor in terms of cost, and it is possible to obtain a long continuous recording image without skewing.

[Embodiment 3] The density distribution data referred to in Embodiment 2 was referenced every time one band was formed, and the paper pressing pressure was adjusted. However, there was a skew due to the density difference in the band due to one band recording. Since the amount is small, it is possible to adjust the paper pressing pressure using the density distribution data of the entire recording area for a plurality of bands.

[Embodiment 4] FIG. 8 shows a structure in the vicinity of a scanning carriage according to a fourth embodiment.

In this embodiment, one paper feed motor 40 is used as a drive source for intermittently feeding the recording paper,
The downstream paper feed roller 28 and the second paper feed roller
The upstream paper feed roller 27 is driven via the clutch 46.

The scanning motor 35 is a drive source for scanning the scanning carriage 34 in the directions of arrows A and B via the scanning belt 47. In this embodiment, a pulse motor is used as the paper feed motor 46 and the scanning motor 35 because accurate paper feed control is required.

The recording paper 38 is the upstream paper feeding second roller 2
When it reaches 7, the second paper feed roller / clutch 43 and the paper feed motor 40 are turned on to convey the recording paper to the paper feed roller 28 on the downstream side on the platen 39.

The recording paper 38 is detected by a paper detection sensor 48 provided on the platen 39, and the sensor information is used for position control, jam control and the like.

When the recording paper 38 reaches the paper feed roller 28, the second paper feed roller / clutch 43 and the paper feed motor 46 are turned off, and the suction operation is performed from the inside of the platen 39 by a suction motor (not shown). 38 is brought into close contact with the platen 39.

Prior to the image recording operation on the recording paper 38, the scanning carriage 34 is moved to the position of the home position sensor 49, then the forward scan is performed in the direction of arrow A, and the cyan C from the predetermined position, Image recording is performed by ejecting magenta M, yellow Y, and black BK inks from the recording head 37. When the image recording for a predetermined length is completed, the scanning carriage 34 is stopped, and conversely, the backward scanning is started in the direction of arrow B, and the scanning carriage 34 is returned to the position of the home position sensor 49. During the backward scan, the paper feed motor 46 feeds the paper for the length recorded by the recording head 37.
The paper feed roller 28 is driven by the arrow C
In the direction of.

In this embodiment, the recording head 37 is the ink jet nozzle of the above-mentioned system, and four nozzles having 256 nozzles assembled in each of Y, M, C and BK are used.

When the scanning carriage 34 stops at the home position detected by the home position sensor 49, the recording head 37 recovers. This is a process for performing a stable recording operation, and in order to prevent unevenness at the start of ejection, which is caused by a change in the viscosity of the ink remaining in the nozzles of the recording head 37, the sheet feeding time, the temperature in the apparatus,
This is a process of performing a pressurizing operation of the recording head 37 and idle ejection of ink under preprogrammed conditions such as ejection time.

By repeating the operation described above, an image is recorded on the entire surface of the recording paper.

As described above, since the platen 39 sucks air from the inside by the suction motor to suck the recording paper to the platen 39, a large number of suction holes are formed in the platen 39 as shown in FIG. . In order to completely suck the recording paper, it is necessary to suck air in this area with the area of the platen having the fine holes covered with the recording paper as a closed space. A method of determining the suction area in the platen based on the size of the paper will be described with reference to FIG.

FIG. 9 is a view of the platen 39 as viewed from the inside (direction opposite to that in FIG. 8). Reference numeral 50 is a suction switching plate, which is always pulled in the direction B by a spring 51. 52
Is a sealing tape of the platen 39, and is connected to the switching plate 50 in such a manner that there is no air leakage. By rotating a motor 53 (a stepping motor is used in this embodiment so that accurate position control can be performed), the switching plate 50 moves in either direction A or B. At this time, for example, when the switching plate 50 moves in the A direction, the seal tape 52 is wound up. When the switching plate 50 moves in the B direction, the sealing tape 52 is fed out. It goes without saying that the seal tape 52 and the platen 39 are configured to be in close contact with each other. As a result, the motor 53 is positive,
By rotating it in either direction, the area inside the platen 39 partitioned by the switching plate 50 and the seal tape 52 can be freely set. Reference numeral 49 is a home position sensor. Reference numeral 54 is a suction pump, and a pressure sensor 55 is installed at the exhaust port of the suction pump 54 so that the exhaust pressure of air can be monitored.

The motor 53, the pressure sensor 55, the suction pump 54, and the home position sensor 49 are connected to a control unit 70, which will be described later, and are controlled by the microprocessor. Air holes having a diameter of 3 mm are regularly formed on the surface of the platen 39 at intervals of 6 mm in all directions, and the recording paper is sucked to the platen 39 by these holes.

FIG. 10 shows the positional relationship between the platen 39 and the recording paper, and recording is performed in the A direction. The recording paper is based on the recording start side, and even if the recording papers have different sizes, one side is the reference as shown in FIG. The switching plate 50 is located at the position 58 for the wide recording sheet 56, and is located at the position 59 for the narrow recording sheet 57. As a result, an airtight chamber is formed within a certain range of the recording paper in the platen, and the recording papers 56 and 57 are attracted to the platen 39.

As shown in FIG. 11, the recording sheet has a suction hole 61.
In the intermediate position, there is a maximum of about 6 mm where a portion is not adsorbed, but in the case of the present embodiment, this is a problem-free numerical value, but it can be improved by further narrowing the intervals of the suction holes.

Next, using the block diagram shown in FIG.
The overall control will be described. Reference numeral 71 is a microprocessor, 72 is a ROM for storing programs, and 73 is a RAM for temporarily storing various data. A driver unit 74 drives the suction pump 54. Reference numeral 75 is a driver portion of the motor 53 that drives the seal tape 52. There are two sensor inputs, one is the home position sensor 4
9 is an input unit 76, and the other is an input unit 77 for the pressure sensor 55. The home position sensor 49 is a light transmission type sensor. Note that the controller unit 70 also performs overall control of the printer unit 3 such as sequence and communication with the scanner unit 1. However, in this description, only the portion related to the suction of the platen 39 will be described.

At the start of copying, the microprocessor 71
Feeds the recording paper to the platen 39. At this time, the stepping motor 53 is simultaneously driven to move the switching plate 50 to the position of the home position sensor 49. When the feeding is completed, the suction pump 54 is driven to start suction. And at the same time, drive the stepping motor 53,
The switching plate 50 is moved in the B direction in FIG. The microprocessor 71 uses the pressure sensor 55 while moving the switching plate.
Monitor the value of.

When the microprocessor detects a point where the pressure has risen from the value of the pressure sensor 55 (when the exhaust amount starts to increase, that is, when air flows in from the suction hole 61), it comes to the end of the recording paper. Detect things. Back up until the pressure reaches a specified value, and obtain the paper size from that position. Since the switching plate 50 is moved by the stepping motor 53, the absolute position from the home position can be obtained by the number of pulses added.

After performing the above operation, the recording operation described above is started. As a matter of course, the paper end in the sub-scanning direction is detected by a paper end detection sensor (not shown) at the same time as the recording is controlled so that the width of the recording paper is not exceeded.

Needless to say, the present invention is not limited to a color image forming apparatus, and can be applied to a single color or a multicolor of four or more colors. Also the recording method,
The present invention is not limited to the inkjet method, but can be applied to thermal transfer, dot impact method, and the like.

[Embodiment 5] The fifth embodiment shows a system in which the switching means of the embodiment shown in FIG. 9 is not used and the suction area changing means is simplified.

As shown in the back side of FIG. 13 (a) and the top side of FIG. 13 (b), the entire back side of the platen 39 is fixedly covered with sheet metal or the like, and only the suction holes are covered with the seal tape 52. . Since the volume of the airtight region is larger than that of the fourth embodiment, it is necessary to increase the capacity of the suction pump, but the structure is simple.

[Sixth Embodiment] A sixth embodiment shows an example in which the exhaust pressure is detected by a wind turbine instead of a pressure sensor. Figure 1
As shown in FIG. 4, the flow rate of exhaust gas is detected by detecting the rotation speed of the wind turbine 81. The light shielding plate 82 is directly connected to the wind turbine 81, and this is detected by the photo interrupter 83, and the microprocessor 71 of the controller unit 70 counts the number of on / off times within a fixed time to obtain the exhaust amount.

[Seventh Embodiment] In the seventh embodiment, instead of detecting the exhaust pressure, the air density in the platen is detected from the drive current flowing through the pump.

The current flowing through the pump increases because the load becomes heavier when the airtightness of the platen becomes higher. Conversely, if the airtightness is low, the load will be low and the current will decrease. The edge of the recording paper can be detected from the increase / decrease in the current. 15 of FIG.
Reference numeral 1 is a resistor for converting an increase / decrease in motor current into a voltage, and a value of about 0.1 to 1 Ω is selected so that the voltage drop is not so large. A capacitor 92 removes a noise component.
Reference numeral 93 is a comparator, and the comparison result is determined by the microprocessor 71 of the control unit 70.

[Embodiment 8] In the eighth embodiment, an example is shown in which the present invention is applied to an image forming apparatus for recording by placing all the recording paper on a mounting table. As shown in FIG. 16, this is a system in which a suction region is two-dimensionally determined by two switching plates 94 and 95. In the sequence, first, the switching plate 94 is moved in the X direction to detect and determine one side of the recording sheet, and then the switching plate 95 is moved in the Y direction to detect and determine the other side of the recording sheet.

Of course, the Y switching plate 95 follows the movement of the X switching plate 94 and is reeled out or unwound from the winding section 96.

(Others) The present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention brings about excellent effects in a recording head and a recording apparatus of the type in which the state of ink is changed by the heat energy. This is because such a system can achieve high density recording and high definition recording.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angle liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the ink jet from the main body of the apparatus is electrically connected to the main body of the apparatus by mounting the recording head. The present invention is also effective when a replaceable chip type recording head which can be supplied or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add the ejection recovery means of the recording head, the preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type or number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet method, it is common to control the temperature of the ink itself within the range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying thermal energy such as ink that is liquefied by applying thermal energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function can be used. It may be a form or the like.

[0076]

As described above, according to the present invention,
By changing the pressure of the paper retainer based on the density distribution of the area to be recorded or recorded, it is possible to perform recording without skew even when performing long continuous printing.

Further, according to the present invention, by providing the mechanism for automatically setting the suction area of the platen to the optimum position according to the size of the recording paper, the user can freely select the size of the paper. . Further, it is possible to prevent troubles such as jamming due to the recording head being caught due to poor suction, jamming due to scratching of the recording paper, and dirt due to the rubbing of the recording paper or damage to the expensive recording head in the worst case.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a copying machine to which the present invention is applied.

FIG. 2 is a sectional view of a copying machine to which the present invention is applied.

FIG. 3 is a perspective view illustrating a paper feeding unit of the printer according to the first embodiment.

FIG. 4 is a flowchart illustrating the operation of the first embodiment.

FIG. 5 is a diagram showing an example of a density distribution on a recording sheet.

FIG. 6 is a perspective view of a carriage unit according to a second embodiment.

FIG. 7 is a flowchart illustrating the operation of the second embodiment.

FIG. 8 is a perspective view of a carriage unit according to a fourth embodiment.

FIG. 9 is a perspective view showing an example of a suction area changing mechanism of the platen.

FIG. 10 is a diagram showing a positional relationship between a platen and recording paper.

FIG. 11 is a diagram showing a positional relationship between a platen and recording paper.

FIG. 12 is a block diagram of an apparatus for controlling suction of recording paper to a platen.

FIG. 13 is a perspective view showing an example of a suction area changing mechanism of the platen.

FIG. 14 is a perspective view showing an example of a suction area changing mechanism of the platen.

FIG. 15 is a perspective view showing an example of a suction area changing mechanism of the platen.

FIG. 16 is a perspective view showing an example of a suction area changing mechanism of the platen.

[Explanation of symbols]

1 Color Image Scanner Section 2 Controller Section 3 Printer Section 27 Paper Feeding Second Roller (Upstream Paper Feed Roller) 28 Paper Feed Roller (Downstream Paper Feed Roller) 29 Roll Paper 34 Scanning Carriage 35 Scanning Motor 37 Recording Head 38 Recording Paper 39 Platen 40, 43, 44 Paper feed motor 41 Control / arithmetic device 42 Recording head drive device 50 Suction force switching plate 51 Spring 52 Seal tape 53 Motor 54 Suction pump 55 Pressure sensor 56, 57 Recording paper 61 Suction hole 70 Controller section 71 Microprocessor 81 Windmill 82 Light-shielding plate 83 Photointerrupter 94 X-switching plate 95 Y-switching plate 96 Winding section R ₁ , R ₂ , R ₃ Divided part of upstream side paper feed roller R ₄ , R ₅ , R ₆ Downstream paper feed Roller split parts RP ₁ , RP ₂ , RP ₃ , RP ₄ , RP ₅ , RP ₆ Paper pressure regulator

Claims (6)

[Claims] 1. A recording head for ejecting ink to perform recording on a recording medium, and means for pressing the recording medium and moving the recording medium in a direction orthogonal to a scanning direction of the recording head. Then, the image forming apparatus is provided with a transfer means having a plurality of divided portions and a means for individually applying a pressure to each of the plurality of divided portions according to the recording density distribution of the recorded image. 2. The image forming apparatus according to claim 1, wherein the transfer unit is a paper feed roller. 3. The image forming apparatus according to claim 1, further comprising means for detecting a recording density distribution of an image recorded on the recording medium. 4. A recording head for ejecting ink to perform recording on a recording medium, a hollow recording medium mounting means having suction holes for sucking the recording medium, and an inside of the mounting means. An image forming apparatus comprising: a suction unit that sucks air, a unit that detects the pressure inside the placing unit, and a unit that continuously changes the suction region of the placing unit. 5. The image forming apparatus according to claim 1, wherein the image forming apparatus is a copying machine. 6. The image forming apparatus according to claim 1, wherein the recording head is an ink jet recording head that ejects ink by utilizing a liquid boiling phenomenon.