JP5910523B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses an ink jet recording apparatus in which an aggregating liquid is applied to a recording medium, ink is drawn on the recording medium on which the aggregating liquid is applied, and light is irradiated to cure. Japanese Patent Application Laid-Open No. H10-228561 proposes storing the coating thickness according to the printing conditions in a memory and adjusting the coating thickness of the aggregation liquid according to the printing conditions.

Japanese Unexamined Patent Publication No. 2011-224796

  An object of the present invention is to provide an image forming apparatus in which an ink receiving layer having a uniform thickness and an adjusted thickness is applied over the entire area.

The first aspect of the present invention is a coating unit for coating an ink receiving liquid on a recording medium being conveyed so that the thickness thereof can be adjusted, and forming an ink receiving layer on the recording medium that receives the ink and is cured by stimulation.
A recording unit for recording an image with ink on an ink receiving layer formed on the recording medium;
A stimulus imparting section for stimulating the ink receiving layer after image recording to cure the ink receiving layer;
A reading unit that reads an image recorded on the ink receiving layer after curing in a width direction intersecting with a conveyance direction of the recording medium ;
A control unit that executes a control for detection that causes the recording unit to record a repeated design that repeats shading in the width direction and causes the reading unit to read the repeated design;
A necessary and sufficient thickness of the ink receiving layer in the coating unit is realized on the basis of design reading data representing a shading waveform that repeats shading in the width direction, obtained by reading the design repeatedly by the reading unit. A determination unit for determining application conditions;
The control unit further controls the application unit based on the application condition determined by the determination unit, thereby causing the application unit to apply an ink receiving layer having a adjusted thickness. The image forming apparatus.

According to a second aspect of the present invention, the control unit alternately and repeatedly executes the change of the coating condition and the detection control until the amplitude of the gray waveform is stabilized regardless of the change in the thickness of the ink receiving layer. The image forming apparatus according to claim 1, wherein:

Claim 3 further comprises a pressing unit that presses a recording medium on which an ink receiving layer cured by stimulation by the stimulation applying unit is formed prior to reading by the reading unit,
The control unit performs detection control in which the repetitive design is recorded in the recording unit and pressed by the pressing unit after being cured by a stimulus given by the stimulus applying unit, and the repetitive design is read by the reading unit. 3. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

According to a fourth aspect of the present invention, the coating unit is further capable of adjusting the balance of the thickness of the ink receiving layer in the width direction intersecting the transport direction of the recording medium,
A first detection unit that detects a balance and an imbalance of the thickness of the ink receiving layer based on a change in amplitude of the amplitude of the grayscale waveform from one end in the width direction toward the other end;
The control unit further includes a change in coating condition in the coating unit in a direction in which the thickness of the ink receiving layer is balanced when the imbalance is detected by the first detection unit, and the detection control. The image forming apparatus according to any one of claims 1 to 3, wherein the image forming apparatus executes the following.

Claim 5
Wherein said difference than the approximate straight line obtained by linear approximation in the width direction of the width direction of the sequence of the difference between the peak value of the peak value and the black side of the adjacent white sides of the shading waveform in advance in the width direction a second detecting unit detect a partial defect below the part for over a defined length,
According to any one of the four claim 1, characterized in that by receiving a detection of the partial defect by the second detecting unit further comprising a notifying unit for notifying the presence of the moiety defects to the user An image forming apparatus.

6. The recording unit according to claim 6, wherein the recording unit is capable of recording using a plurality of colors of ink, and the control unit repeats the repetitive design with one color ink in the recording unit in executing the detection control. Is recorded,
The control unit further includes an ink receiving layer having a necessary and sufficient thickness corresponding to recording using one color ink determined by the determination unit in a mode in which the recording unit performs recording using a plurality of colors of ink. The application condition for forming the ink receiving layer having a thickness corresponding to the recording using a plurality of colors of ink is calculated based on the application condition for forming the ink, and the ink receiving layer is applied under the calculated application condition. 6. The image forming apparatus according to claim 1, wherein the image forming apparatus controls an application unit.

  According to the image forming apparatus of the first aspect, the ink receiving layer having the adjusted thickness is applied.

  According to the image forming apparatus of the second aspect, the accuracy of the thickness of the ink receiving layer can be improved as compared with the case where the repetition is not performed.

  According to the image forming apparatus of the third aspect, the detection accuracy of the application condition for forming the ink receiving layer having an appropriate thickness can be improved as compared with the case where the pressing portion is not provided.

  According to the image forming apparatus of claim 4, when there is an imbalance in the width direction of the ink receiving layer, the ink receiving layer in which the imbalance is corrected is applied.

  According to the image forming apparatus of the fifth aspect, it is possible to make the user aware of a defect that cannot be recovered by adjusting the thickness.

  According to the image forming apparatus of the sixth aspect, it is possible to reduce consumption of the ink coating liquid and ink for detection as compared with the case where the necessary thickness is detected using a plurality of colors of ink.

1 is a schematic view of an image forming apparatus according to a first embodiment of the present invention when viewed from the side. FIG. 2 is a schematic diagram when the image forming apparatus shown in FIG. 1 is viewed from above. It is the block diagram which showed the structure of the application part. It is the block diagram which showed the structure of the application | coating head which comprises an application part. It is explanatory drawing regarding recording and reading of a line pattern. It is the figure which showed the graph which plotted said difference (DELTA) D in the width direction. It is the figure which showed the data when a partial nonuniformity exists. 5 is a flowchart illustrating a processing procedure executed in a coating thickness adjustment mode of the image forming apparatus according to the first embodiment. It is the schematic diagram which showed the change of amplitude b (m). FIG. 5 is a diagram illustrating coating conditions (Hg, Vg) for forming an ink receiving layer having a minimum necessary thickness for each of recording medium types A, B, and C. It is a schematic diagram of the image forming apparatus of 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below.

  FIG. 1 is a schematic view of the image forming apparatus according to the first embodiment of the present invention as viewed from the side. 2 is a schematic diagram when the image forming apparatus shown in FIG. 1 is viewed from above. However, in FIG. 2, the feeding roll 10, the take-up roll 60, and the like are not shown and act on the recording medium P. The elements to be simplified are shown side by side in the transport direction (arrow A).

  In this image forming apparatus 1A, a long recording medium P wound around a delivery roll 10 shown in FIG. 1 is delivered from the delivery roll 10 and conveyed in a conveyance direction indicated by an arrow A, and the application unit 20 and a backup unit are backed up. It passes between the rolls 71, and is guided to the rolls 72 and 73 via the recording unit 30, the curing unit 40, and the reading unit 50, and is wound around the winding roll 60.

  FIG. 2 shows an ink receiving layer 29 coated on the recording medium P by the coating unit 20 and a line pattern 80 composed of vertical stripes recorded on the recording medium P. Details of the line pattern 80 will be described later.

  The recording medium P is, for example, a resin film, and is a recording medium that does not soak ink, and therefore cannot be recorded with ink as it is.

  The application unit 20 applies an ink receiving liquid onto the recording medium P conveyed in the direction of arrow A, and forms an ink receiving layer 29 (see FIG. 2) on the recording medium P. The ink receiving layer 29 penetrates the ink in the thickness direction without causing the ink to be largely squeezed sideways, and is cured by receiving stimulation (ultraviolet (UV) irradiation in the present embodiment) and being cured in the ink receiving layer 29. It has the property of confining ink. In the present embodiment, the coating unit 20 has a structure that can freely adjust the thickness balance in the width direction on the recording medium P that intersects the conveyance direction (arrow A direction) of the recording medium P and can adjust the thickness of the entire area in the width direction. Have

  The recording unit 30 includes four recording heads that use inks of four colors of C (cyan), M (magenta), Y (yellow), and K (black). An image is recorded on the ink receiving layer 29.

  The curing unit 40 cures the ink receiving layer 29 by applying stimulation (in this embodiment, UV irradiation) to the ink receiving layer 29.

  In the present embodiment, the reading unit 50 includes a reading head including a plurality of CCD sensors arranged in the width direction, and repeatedly reads an image recorded on the ink receiving layer 29 in the width direction. A CMOS sensor may be employed instead of the CCD sensor.

  The image forming apparatus 1A of the present embodiment has a coating thickness adjustment mode and a print mode. The coating thickness adjustment mode is a mode for adjusting the balance of the thickness of the ink receiving layer 29 and the thickness in the width direction. In the coating thickness adjustment mode, the line pattern 80 shown in FIG. 2 is recorded by the recording unit 30, and the line pattern 80 is read by the reading unit 50.

  The print mode is a mode for recording an image based on an image signal input from the outside. In this print mode, the reading unit 50 reads an image recorded in this print mode and monitors whether an image formation without image quality defects is being performed.

  FIG. 3 is a configuration diagram illustrating the structure of the application unit 20.

  The application unit 20 shown in a simplified manner in FIG. 1 includes a tank 21, a pump 22, and an application head 23.

  The tank 21 is a tank that stores ink receiving liquid. The pump 22 feeds the ink receiving liquid stored in the tank 21 to the coating head 23. The coating head 23 is provided with a die coater 231 (see FIG. 4) provided with a slit at the front end facing the recording medium P. The ink receiving liquid sent from the pump 22 to the coating head 23 is pushed out from a slit provided at the tip of the die coater 231 and applied onto the recording medium P, whereby an ink receiving layer 29 is formed on the recording medium P.

  FIG. 4 is a configuration diagram showing the structure of the coating head constituting the coating unit.

  The coating head 23 is provided with the above-described die coater 231, and a slit for pushing out the ink receiving liquid is provided at the tip 231 a of the die coater 231 on the recording medium P side.

  In the die coater 231, both ends in the width direction of the recording medium P are supported by the slider 233 via the rotation shaft 232. The slider 233 is structured to move up and down by a motor 234. Here, the slider 233 and the motor 234 are provided on both sides in the width direction of the die coater 231, and when the left and right motors 234 are rotated, the left gap d1 and the right gap between the die coater 231 and the recording medium P are rotated. d2 is adjusted independently.

Here, on the recording medium P, in order to form an ink receiving layer having an appropriate thickness without thickness unevenness in the width direction, the left and right gaps d1 and d2 between the die coater 231 and the recording medium P and the ink are used. It is necessary to adjust the flow rate of the receiving liquid appropriately. Here, the gaps d1 and d2 are adjusted by controlling the rotation of the motor 234, and the flow rate of the ink receiving liquid is adjusted by controlling the rotation of the pump 22. here,
Flow rate = application thickness × application width × conveying speed of the recording medium P is established, and the flow rate can be calculated from this equation.

  As described above, the image forming apparatus 1A of the present embodiment has the coating thickness adjustment mode and the print mode. In the following, first, a method of detecting the coating thickness unevenness in the width direction and the appropriate coating thickness employed in the coating thickness adjustment mode will be described.

  In this coating thickness adjustment mode, the vertical stripe pattern line pattern 80 shown in FIG. 2 is recorded on the ink receiving layer formed on the recording medium P in the recording unit 30, and the line pattern 80 is read by the reading unit 50. .

  FIG. 5 is an explanatory diagram regarding recording and reading of the line pattern.

FIG. 5A shows the resolution P _head of the recording head in the recording unit 30. The resolution P _head is, for example, 1200 dpi. In this case, nozzles that eject ink are arranged at a pitch of 21.1 μm in the width direction in this recording head. Here, only one nozzle for every 10 nozzles is ejected to record a vertical line.

  FIG. 5B shows a line pattern composed of the vertical lines.

  In the example shown here, a line pattern consisting of vertical lines with a pitch of 212 μm is recorded.

FIG. 5C shows the resolution P _ccd (dpi) of the reading head provided in the reading unit 50 (see FIG. 1). Here, as an example, as described above, a recording head having a resolution of 1200 dpi (nozzle pitch 21.1 μm) is recorded every 10 nozzles, and a 212 μm pitch vertical line is 600 pixels (CCD sensor array pitch = 42.3 μm) read head. Is read and digitized to obtain the density distribution of the line pattern. The higher the number of bits, the better the quantization from analog data obtained by the read head (CCD sensor) to digital data is, but here, as an example, it is 2 8 bits (256 bits). That is, black data has a value of 0 and white data has a value of 255.

  The length of the line pattern shown in FIG. 5B in the carrying direction (the direction of arrow A shown in FIG. 2) is desirably 10 pixels or more in terms of the number of pixels in the carrying direction of reading by the CCD sensor. An average value of data of pixels or more is adopted. Specifically, as an example, when the recording resolution in the conveyance direction to the recording medium P is 1200 dpi, the reading frequency of the reading head is 100 Hz, and the conveyance speed of the recording medium P is 500 mm / sec, the length is 50 mm. Therefore, 2362 dots are continuously ejected from the ink ejection nozzle to render the vertical line.

  FIG. 5D shows digital data created by the above reading. The horizontal axis represents the CCD sensor arrangement direction (width direction of the recording medium P), and the vertical axis represents density data (average value in the transport direction) obtained by reading.

  When an ink-receiving layer having a sufficient thickness is formed on the recording medium P, a gray waveform having a substantially constant and large amplitude is obtained, which is close to a sine wave as shown by graph a in FIG.

  On the other hand, if the thickness of the ink receiving layer is insufficient, the ink used for recording the vertical line spreads laterally and spreads, so that the valley of the light and shade waveform is wider than in the normal state as shown in the graph b in FIG. And a small amplitude. Further, when the thickness of the ink receiving layer is insufficient and the thickness is unbalanced in the width direction, the amplitude on the thinner side becomes smaller.

  On the other hand, if the thickness of the ink receiving layer is too thick, there is no problem in recording itself, but the flexibility of the recording medium P after the ink receiving layer is cured is lost, and the recording medium P is curled. Inconveniences such as insufficient UV irradiation resulting in insufficient curing, and excessive consumption of the ink receiving liquid, resulting in increased costs.

  Here, after data such as the graph a or the graph b is obtained, the black side peak (Dmin (n)) is obtained by fitting to the curve as shown by a two-dot chain line in FIG. Similarly, the white side peak (Dmax (n)) is also acquired.

Specifically, in this embodiment, the relationship between the pixel pitch of the CCD sensor and the pitch of the vertical line is: line pitch / pixel pitch = 212 μm / 42 μm = 5
A black peak and a white peak are periodically arranged every five pixels of the CCD sensor. Here, using this, CCD data is periodically acquired. That is, black data is acquired for every five pixels, and data on both sides thereof are also acquired, and parabolic approximation is performed with the acquired three points of data to acquire a black peak (Dmin (n)). For the white side peak, the position of the pixel to be acquired is acquired with a half-cycle shift from the position of the black side peak pixel, and similarly, a parabolic approximation peak is acquired (Dmax (n)).

  In this way, the peaks Dmax (n) and Dmin (n) on both the white side and the black side are obtained, and the difference ΔD = (Dmax (n) −Dmin (n)) between adjacent peaks is obtained in the width direction. calculate.

  FIG. 6 is a graph showing the difference ΔD plotted in the width direction.

Here, from the plotted difference ΔD, an approximate straight line y = a · n + b
And then the difference from the approximate line for each plot ΔE (n) = y (n) −ΔD (n)
n = 1, 2,...
Is calculated.

The balance of the coating thickness on the left and right in the width direction is as follows. The slope a of the above approximate line is −ΔA ≦ a ≦ + ΔA (ΔA is an allowable error and is determined by the user)
Is determined by whether or not the above is satisfied. When this conditional expression is satisfied, that is, when a≈0, it is determined that the left and right imbalances of the coating thickness are not balanced and are balanced.

  Graph a is an example when an ink receiving layer having an appropriate thickness is formed and there is no imbalance between the coating thicknesses on the left and right sides in the width direction. Even if the coating thickness of the ink receiving layer is greater than this, ΔD does not increase, so that it is determined to be an appropriate thickness.

  In the graph b, the approximate straight line ΔD is inclined, which indicates that the coating thickness on the left and right in the width direction is unbalanced.

  Further, the graph c shows that although the approximate straight line is not inclined, the amplitude ΔD is smaller than that of the graph a and the coating thickness is equal to the left and right, but the coating thickness is too thin.

  Here, it is determined whether or not there is partial unevenness.

  FIG. 7 is a diagram showing data when partial unevenness exists.

If the above-mentioned Δ E (n) data is negative for a predetermined number of times continuously, it is determined as partial unevenness.

That is, here, the user specifies the width L (mm) of the partial unevenness to be detected in advance,
△ Number of consecutive E minus x nozzle pitch> L
When this conditional expression is satisfied, it is determined that partial unevenness has occurred.

In the example shown in FIG. 7, seven consecutive items from the nth to the n + 6th satisfy Δ E <0.

  In the graph of FIG. 7, when the nth nozzle number is 101, the next n + 1th nozzle number is 111 ahead of 111. Therefore, the interval between the adjacent nozzles is 10 × 21 μm = 211 μm.

Therefore, 7 × 211 μm = 1477 μm
Thus, it can be seen that there is a partial unevenness of 1477 μm.

When L = 1000 μm is set by the user,
1477 μm> L = 1000 μm
And it is determined as partial unevenness.

  Here, although referred to as partial unevenness, the cause of partial unevenness is not specified, and the cause is not limited to uneven application of the ink receiving liquid, but the cause of the nozzles arranged in the recording head. There may be a case of a defect and a defect of a recording head.

  FIG. 8 is a flowchart showing a processing procedure executed in the coating thickness adjustment mode of the image forming apparatus of the first embodiment.

  This coating thickness adjustment mode is executed at various timings at which the coating thickness of the ink receiving liquid may vary, such as when the image forming apparatus is turned on, when the recording medium is replaced, and when the ink receiving liquid is replaced.

  In this coating thickness adjustment mode, first, the supply amount of the ink receiving liquid is set to a sufficiently small amount Vo, and the height position H of the die coater 231 (see FIG. 4) is set to the die coater 231 (see FIG. 4) and the recording medium. The gaps d1 and d2 with P are set to a sufficiently narrow position Ho, and an ink receiving liquid is applied to the recording medium P to form an ink receiving layer on the recording medium P (step S01).

A line pattern 80 (see FIGS. 2 and 5B) is recorded on the ink receiving layer formed on the recording medium P (step S02), and the line pattern is read after the ink receiving layer is cured by UV irradiation. To obtain gray scale waveform data as shown in FIG. 5D (step S03). Then
y (n) = a · n + b
And △ E (n)
n = 1, 2,...
Is calculated (step S04). These meanings have already been described with reference to FIG. 6 and FIG.

next,
△ Number of consecutive negative Es × Nozzle pitch> L
(Step S04) The meaning of this equation has already been described with reference to FIG.

  If the inequality in step S05 is satisfied, the number of times i passing through step S05 is increased by 1 from the initial i = 0 (i = i + 1), and the process proceeds to step S06, where the supply amount of ink receiving liquid by the pump 22 is reduced by one. The ink receiving layer is formed by increasing the level ΔV, and the line pattern recording (step S02), reading (step S03), and calculation (step S04) are executed again. Here, the supply amount increase ΔV is a value set in advance by the user, and is a value set so that the coating thickness is increased by 2 μm, for example.

  In step S05, even if i reaches a predetermined value I, that is, when the inequality is satisfied even at i = I, a warning is given to the user that partial unevenness exists. The reason why the warning is not issued only at the first time of i = 0 in step S05 is that if the supply amount of the ink receiving liquid is too small, the liquid is likely to run out, and the above inequality may be satisfied even if the apparatus is not defective. It is.

If it is determined in step S05 that the inequality is not satisfied at the stage of i <I, the process proceeds to step S07. In step S07, the slope a of the approximate straight line is
-△ A <a <+ △ A
Is satisfied. The fact that this inequality is not satisfied means that the coating thickness is unbalanced in the width direction as shown in the graph b in FIG. 6, and j is incremented by 1 (j = j + 1) and the process proceeds to step S08. The height position of the die coater 231 is increased by ΔH. Here, since the gap d1 or d2 shown in FIG. 6 is narrower depending on whether the inclination a is negative or positive, the height position on one side where the gap between the left and right is narrow is increased by ΔH. In this way, the ink receiving layer is continuously formed, and line pattern recording (step S02), reading (step S03), and calculation (step S04) are executed.

  Here, the adjustment amount ΔH of the height position of the die coater 231 is a value set in advance by the user, for example, ΔH = 2 μm. At this time, the determination in step S05 may be performed again, but since it has been confirmed that there is no partial unevenness, step S05 may be skipped.

  If the imbalance between the left and right coating thicknesses is not resolved even when j reaches a predetermined value J in step S07, a warning to that effect is output to the user.

  If it is determined in step S07 that the difference between the left and right coating thicknesses has been resolved (−ΔA <a <ΔA is satisfied) before j = J is reached, this time, the die coater 231 (see FIG. 4) is increased. The left and right positions are increased by ΔH to increase the left and right gaps d1, d2 by the same amount, and the amount of ink receiving liquid supplied by the pump 22 (see FIG. 3) is further increased by ΔV (step S09). .

  Next, the process proceeds to step S10. However, the determination in step S10 is skipped only twice for the first m = 0 and the second m = 1, and m is incremented by 1, and the process returns to step S02.

When step S10 is reached after the third time (m = 2), y (m) = a (m) · n + b (m) calculated in step S04 (n is the nozzle number shown in FIG. 6, m is m () represents the m-th data.) Using b (m) calculated this time, b (m-1) calculated last time, and b (m-2) calculated last time,
| B (m) -b (m-1) | <ΔB
And | b (m) -b (m-2) | <ΔB
However, although ΔB is a value determined in advance by the user, it is determined whether or not it is established. The meaning of this inequality will be described later.

  If this inequality is not satisfied, the process returns to step S02, the line pattern is recorded once again, and the process proceeds to step S10.

  When the above inequality is established in step S10, the process proceeds to step S11, where the height position H of the die coater 231 and the ink receiving liquid supply amount V by the pump are returned to the settings at m-2, and the slider at m-2. The position H and the supply amount V are stored in the memory as the position Hg and supply amount Vg as application conditions for forming the ink receiving layer having the minimum necessary thickness, and the application amount adjustment mode is terminated.

  In step S10, even if m = M is reached, if the inequality in step S10 is not satisfied, a warning is issued to the user that some abnormality has occurred. Here, M is a value determined in advance by the user.

  FIG. 9 is a schematic diagram showing changes in b (m).

  Here, b (m) represents the m-th amplitude, and H (m) and V (m) represent the height position of the m-th die coater and the supply amount of the ink receiving liquid, respectively.

  In step S09, when the height position H of the die coater is increased by ΔH and the supply amount V of the ink receiving liquid is increased by ΔV, the thickness of the ink receiving layer is increased accordingly. When the thickness of the ink receiving layer is insufficient, the ink is recorded on the ink receiving layer having the insufficient thickness. As a result, the ink spreads laterally without entering the ink receiving layer in the vertical direction. For this reason, b (m) representing the amplitude of the waveform shown in FIG. 5D is a small value. As the thickness of the ink receiving layer gradually increases, the amplitude b (m) also gradually increases. However, when the thickness of the ink receiving layer reaches a sufficient thickness, the ink enters the ink receiving layer in the vertical direction and spreads laterally. The amplitude b (m) hardly changes even if the ink receiving layer is made thicker. FIG. 9 shows the change of the amplitude b (m), and FIG. 9 shows that a saturation state is reached where the amplitude b hardly changes at the stage of m-2.

  Here, although not particularly mentioned in the description of the flowchart of FIG. 8, when recording a line pattern in the coating amount adjustment mode, recording is performed with, for example, K color ink among the four colors of C, M, Y, and K. Only the head to be used is used, and the ink of the K color ink with a printing rate of 100% is used. Here, the printing rate of 100% means the maximum amount of ink ejected at one time by one nozzle when an image is recorded in the print mode.

In this case, the coating conditions for forming the ink receiving layer having the necessary minimum thickness for one color are set according to the sequence of FIG. 8, but the ink receiving layer having the required minimum thickness has thermal expansion of the member during image recording in the print mode. As a result, the coating thickness of the ink receiving layer becomes thin, and the ink used for recording may bleed sideways. Therefore, preferably, the application condition (Hg, Vg) for forming the ink receiving layer having the minimum necessary thickness obtained in accordance with the sequence of FIG. 8 is multiplied by an increase rate Rg (for example, Rg = 1.2), and the slider height is increased. Position H and ink receiving liquid supply amount V
H = Hg × Rs
V = Hg × Rs
Set as. The increase rate Rg may be configured to be input to the memory in advance by the user, or may be recorded in advance as a fixed value in the memory.

  Further, here, for example, it has been described that a test pattern is recorded with one color of K color and a printing rate of 100%. However, the sequence shown in FIG. It is also possible to find a coating condition that realizes a necessary minimum thickness at the time of%, and convert the coating condition of the necessary minimum thickness into a coating condition of the necessary minimum thickness when the printing rate is 100%.

  In the print mode, when recording a color image using four colors of C, M, Y, and K, instead of recording a test pattern using four colors of C, M, Y, and K, The minimum required for recording a color image by multiplying the maximum printing ratio exceeding 100% (for example, 400%) by Rc times the coating conditions for realizing the minimum required thickness when the printing ratio for one K color is 100%. You may calculate the application | coating conditions which implement | achieve thickness.

That is, at this time,
H = Hg × Rc
V = Hg × Rc
It becomes. Here, Rc is a value input to the memory in advance by the user, and is, for example, about Rc = 4.2 (4.0 corresponds to a printing rate of 400% and 0.2 is a margin).

  Further, in the sequence shown in FIG. 8, every time the mode shifts to the coating thickness adjustment mode, the initial die coater position Ho and the initial supply amount Vo are started. In this case, the thickness of the formed ink receiving layer is started every time, and a large value is set as the values of I, J, and M shown in FIG. 8, and each of the loops i, j, and m is set. In addition, the number of loops increases in time, and the consumption of the recording medium P, ink receiving liquid, and ink consumed for adjusting the coating thickness is large. This is unavoidable when using a new type of recording medium, but when using the same type of recording medium as previously used, the number of loops may be reduced as follows.

  FIG. 10 is a diagram showing coating conditions (Hg, Vg) for forming the ink receiving layer having the minimum necessary thickness for each of the types A, B, and C of the recording medium.

  Here, when Hg and Vg are stored in the memory in step S11 of FIG. 8, as shown in FIG. 10, they are stored in association with the type of the recording medium used at that time.

  The type of the recording medium may be designated by the user when setting a new recording medium in the image forming apparatus 1A shown in FIG. 1, and the type is recorded on the recording medium with a barcode or the like and is read. It is good also as a system.

  Here, it is assumed that the newly set recording medium is the same type A recording medium as the recording medium that has been used before.

At this time, instead of Vo and Ho in step S01 in FIG.
Initial die coater position Ho = Ha × (1-Ro)
Initial supply amount Vo = Va × (1-Ro)
Is adopted.

  Here, Ro is a coefficient for forming an ink-receiving layer having a thin layer thickness such as 0.2, for example, to which the safety coefficient is added to the maximum value of the predicted fluctuation amount obtained from the previous Va and Ha.

  In this way, the number of loops may be reduced by determining the initial supply amount Vo and the initial die coater position Ho with reference to the data at the coating thickness adjustment performed so far.

  FIG. 11 is a schematic diagram of an image forming apparatus according to the second embodiment of the present invention.

  Here, the same constituent elements as those of the image forming apparatus 1A of the first embodiment shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. 1, and only differences will be described.

  The image forming apparatus 1B of the second embodiment shown in FIG. 1 is pressed against the surface of the ink receiving layer in addition to the components provided in the image forming apparatus 1A of the first embodiment shown in FIG. A sliding blade 90 that slides on the surface is provided. The sliding blade 90 is a member used only in the coating thickness adjustment mode, and is preferably separated from the surface in the print mode.

  The sliding blade 90 slides on the surface of the ink receiving layer after being cured by UV irradiation at the curing unit 40.

  In the description of the image forming apparatus 1A according to the first embodiment, it has been described that if the thickness of the ink receiving layer is too thin, the ink bleeds and spreads sideways. However, the ink receiving layer is adjusted so as not to bleed as much as possible. Depending on the type of ink receiving liquid, when the thickness of the ink receiving layer is too thin, the amount of ink that does not spread sideways and is not absorbed by the ink receiving layer remains on the ink receiving layer. It is possible to become. In that case, the reading unit 50 reads the ink density of the ink absorbed in the ink receiving layer and the ink remaining on the ink receiving layer. That is, in this case, even if the thickness of the ink receiving layer is insufficient, a large value of data is obtained as the amplitude b, and a correct change of b (m) shown in FIG. 9 cannot be obtained.

  On the other hand, in the case of the image forming apparatus 1B of the second embodiment shown in FIG. 11, the sliding blade 90 is provided and slides on the surface of the ink receiving layer after curing, so that the ink receiving layer cannot be absorbed completely. The ink remaining on the surface of the ink receiving layer is pushed and spread by the sliding blade 90, whereby it is possible to obtain the same ink spreading as when the ink enters the ink receiving layer and splatters horizontally. It is possible to obtain accurate data as shown in FIG.

  In the image forming apparatus 1B according to the second embodiment, an example in which the sliding blade 90 is provided is shown. However, sliding is not always necessary, and the cured ink receiving layer is sandwiched with the recording medium P. A pressure roller for pressing may be provided to spread the ink on the surface of the ink receiving layer on the surface of the ink receiving layer.

  Further, here, an example has been described in which the coating unit 20 is provided with a die coater, and the thickness of the ink receiving layer is changed by changing the height position of the die coater and the amount of ink receiving liquid supplied, but in the image forming apparatus of the present invention. The application unit is not limited to the one provided with the die coater, and any application member may be used as long as the application member can adjust the application thickness and adjust the right and left balance of the application thickness in the width direction. . For example, the left and right gaps in the width direction with the recording medium can be adjusted independently, and a roller that can adjust the rotation speed and a pump that supplies ink receiving liquid to the rollers with a variable supply amount are provided. The right and left balance of the coating thickness may be adjusted, and the coating thickness may be adjusted by adjusting the amount of ink receiving liquid supplied by the pump and the rotational speed of the roller.

  Also, here, in the coating thickness adjustment mode for finding the coating part that can adjust both the left and right balance of the coating thickness and the coating thickness, and the coating conditions for both the left and right balance of the coating thickness and the coating thickness. Although the processing (FIG. 8) is shown, the application thickness may be adjusted only by adjusting the application thickness, for example, by adopting an application structure that is guaranteed with mechanical accuracy.

  In addition, here, it has been described that the ink receiving layer has a property of being cured by UV irradiation. However, instead of UV irradiation, for example, an ink receiving layer that is cured by heating may be used to be a curing portion that applies heat. Any ink-receiving layer that cures the ink-receiving layer by applying a stimulus for curing the ink-receiving layer used may be used.

DESCRIPTION OF SYMBOLS 1A, 1B Image forming apparatus 10 Delivery roll 20 Application | coating part 21 Tank 22 Pump 23 Application | coating head 29 Ink receiving layer 30 Recording part 40 Curing part 50 Reading part 60 Take-up roll 71 Backup roll 72, 73 Roll 80 Line pattern 90 Sliding Blade 231 Die coater 231a Recording medium side tip 232 Rotating shaft 233 Slider 234 Motor

Claims (6)

An application part for applying an ink receiving liquid on the recording medium being conveyed so that the thickness thereof can be adjusted, and forming an ink receiving layer on the recording medium that receives the ink and cures upon receiving the stimulus;
A recording unit for recording an image with ink on an ink receiving layer formed on the recording medium;
A stimulus imparting section for stimulating the ink receiving layer after image recording to cure the ink receiving layer;
A reading unit that reads an image recorded on the ink receiving layer after curing in a width direction intersecting with a conveyance direction of the recording medium ;
A control unit that executes a control for detection that causes the recording unit to record a repeated design that repeats shading in the width direction and causes the reading unit to read the repeated design;
A necessary and sufficient thickness of the ink receiving layer in the coating unit is realized on the basis of design reading data representing a shading waveform that repeats shading in the width direction, obtained by reading the design repeatedly by the reading unit. A determination unit for determining application conditions;
The control unit further controls the application unit based on the application condition determined by the determination unit, thereby causing the application unit to apply an ink receiving layer having a adjusted thickness. Image forming apparatus. The control unit repeatedly executes the change of the coating condition and the detection control in the coating unit alternately until the amplitude of the gray waveform is stabilized regardless of the change in the thickness of the ink receiving layer. The image forming apparatus according to claim 1. A pressing unit that presses the recording medium on which the ink receiving layer cured by stimulation by the stimulation applying unit is formed prior to reading by the reading unit;
The control unit performs detection control in which the repetitive design is recorded in the recording unit and pressed by the pressing unit after being cured by a stimulus given by the stimulus applying unit, and the repetitive design is read by the reading unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The application unit is further capable of freely adjusting the balance of the thickness in the width direction of the ink receiving layer intersecting the transport direction of the recording medium,
A first detection unit that detects a balance and an imbalance of the thickness of the ink receiving layer based on a change in amplitude of the amplitude of the grayscale waveform from one end in the width direction toward the other end;
The control unit further includes a change in coating condition in the coating unit in a direction in which the thickness of the ink receiving layer is balanced when the imbalance is detected by the first detection unit, and the detection control. 4. The image forming apparatus according to claim 1, wherein the image forming apparatus executes the following. Wherein said difference than the approximate straight line obtained by linear approximation in the width direction of the width direction of the sequence of the difference between the peak value of the peak value and the black side of the adjacent white sides of the shading waveform in advance in the width direction a second detecting unit detect a partial defect below the part for over a defined length,
According to any one of the four claim 1, characterized in that by receiving a detection of the partial defect by the second detecting unit further comprising a notifying unit for notifying the presence of the moiety defects to the user Image forming apparatus. The recording unit is a recording unit capable of recording using a plurality of colors of ink, and the control unit causes the recording unit to record the repetitive design with one color ink when executing the detection control. There,
In the mode in which the recording unit performs recording using a plurality of colors of ink, the control unit further receives an ink having a necessary and sufficient thickness corresponding to the recording using one color of ink determined by the determination unit. Based on the coating conditions for forming the layer, the coating conditions for forming the ink receiving layer having a thickness corresponding to the recording using a plurality of colors of ink are calculated, and the ink receiving layer is applied under the calculated coating conditions. The image forming apparatus according to claim 1, wherein the application unit is controlled.

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