Image forming apparatus with a correction recording condition feature and related method

What is claimed is:

1. An image forming apparatus comprising:

(a) an image forming head having a plurality of recording elements arranged with non-uniformity therebetween, said image forming head being drivable by a driving signal so as to form a predetermined pattern image;

(b) correcting means for correcting the non-uniformity between the plurality of recording elements using plural correcting conditions;

(c) display means for numerically displaying the plural correcting conditions for the plurality of recording elements, the plural correcting conditions being displayed simultaneously so that a user of said image forming apparatus can visually compare the plural correcting conditions;

(d) changing means for changing the plural correcting conditions;

(e) control means for controlling the image forming head to form the predetermined pattern image based upon the plural correcting conditions changed by said changing means; and

(f) means for generating a controlling signal for said display means to control said display means to display the plural correcting conditions changed by said changing means.

2. An apparatus according to claim 1, wherein the plural correcting conditions are used to correct image data supplied to the plurality of recording elements.

3. An apparatus according to claim 1, wherein said control means controls said image forming head to form the predetermined pattern image based on predetermined image data input to said image forming head, the predetermined image data having a predetermined image density.

4. An apparatus according to claim 1, wherein said control means controls formation of the predetermined pattern image after a recording sheet conveyance is stabilized.

5. An apparatus according to claim 1, wherein the plural correcting conditions comprise correcting conditions for each of the plurality of recording elements.

6. An apparatus according to claim 1, wherein the plurality of recording elements are arranged in groups; and

wherein the plural correcting conditions comprise correcting conditions for each group of the plurality of recording elements.

7. An apparatus according to claim 1, wherein the plurality of recording elements eject liquid droplets.

8. An apparatus according to claim 7, wherein the plurality of recording elements generate thermal energy to eject the liquid droplets.

9. An image forming apparatus having plural recording elements, said image forming apparatus comprising:

(a) memory means for storing plural correction data corresponding to output characteristics of the plural recording elements, the plural correction data for reducing non-uniformity in the plural recording elements;

(b) inputting means for inputting image data from which the plural recording elements form an image;

(c) correcting means for correcting the image data input by said inputting means using the plural correction data stored in said memory means;

(d) display means for numerically displaying the plural correction data stored in said memory means, said display means also displaying difference information relating to a difference in correction between the plural correction data;

(e) changing means for changing the plural correction data displayed by said display means; and

(f) means for generating a driving signal for driving said display means in accordance with a state of said correcting means.

10. An apparatus according to claim 9 wherein said memory means includes first memory means for storing initial correction data for the plural recording elements, second memory means for storing correction data changed by said changing means, and third memory means for storing the correction data from the second memory means.

11. An apparatus according to claim 10, further comprising:

(g) instruction inputting means for inputting an instruction to transfer the correction data from the second memory means to the third memory means.

12. An apparatus according to claim 10, further comprising:

(g) instruction inputting means for inputting an instruction to transfer the correction data from the first memory means to the third memory means.

13. An apparatus according to claim 10, further comprising:

(g) instruction inputting means for inputting an instruction to transfer the correction data from the first memory means to the second memory means.

14. An apparatus according to claim 10, further comprising comparing means for comparing a content of the first memory means to a content of the second memory means;

wherein said display means displays the plural correction data only when the comparing means determines that the content of the first memory means and the content of the second memory means are unequal.

15. An apparatus according to claim 9, further comprising display control means for terminating a display of the plural correction data by said display means in accordance with an input second instruction which is different from the input first instruction; and

recording control means for recording a predetermined reference image in response to an input third instruction in a case where the plural correction data is displayed by said display means, and for performing a normal image recording operation in response to the input third instruction in a case where the plural correction data is not displayed by said display means.

16. An apparatus according to claim 9, wherein the plural correction data is supplied for each of the plural recording elements.

17. An apparatus according to claim 9, wherein the plural recording elements are arranged into groups; and

wherein the plural correction data displayed by said display means comprises correction data for each group of the plural recording elements.

18. An apparatus according to claim 9, wherein the plural recording elements eject liquid droplets.

19. An apparatus according to claim 18, wherein the plural recording elements generate thermal energy to eject the liquid droplets.

20. An apparatus comprising:

(a) a color image forming head having a plurality of recording elements arranged with non-uniformity therebetween, said color image forming head being drivable by a driving signal so as to form a predetermined pattern image;

(b) correcting means for correcting a non-uniformity between the plurality of recording elements using plural correcting conditions;

(c) changing means for manually changing a correcting condition for one of the plurality of recording elements to reduce the non-uniformity in the plurality of recording elements; and

(d) display means for numerically displaying the plural correcting conditions for the plurality of recording elements, the plural correcting conditions being displayed simultaneously so that a user of said apparatus can visually compare the plural correcting conditions.

21. An apparatus according to claim 20, wherein the plural correcting conditions correct image data supplied to the plurality of recording elements.

22. An apparatus according to claim 20, wherein the plural correcting conditions comprise a correcting condition for each of the plurality of recording elements.

23. An apparatus according to claim 20, wherein the plurality of recording elements are arranged into groups, with each group for recording one color component of plural color components which form color images; and

wherein the plural correcting conditions comprise correcting conditions for each group in the plurality of recording elements.

24. An apparatus according to claim 20, wherein the plurality of recording elements eject liquid droplets.

25. An apparatus according to claim 24, wherein the plurality of recording elements generate thermal energy to eject the liquid droplets.

26. An image forming apparatus comprising:

(a) an image recording head having a plurality of recording elements disposed in groups;

(b) memory means for storing correction data corresponding to output characteristics of the plurality of recording elements;

(c) inputting means for inputting image data from which an image is to be formed;

(d) correcting means for correcting the image data input by said inputting means using the correction data stored in said memory means; and

(e) display means for providing a graphic display of the correction data for the plurality of recording elements so that a user of said image forming apparatus can compare correction data for the plurality of recording elements.

27. An apparatus according to claim 26, wherein said display means displays a part of the graphic display in an enlarged scale in accordance with an input second instruction.

28. An apparatus according to claim 27, wherein the plurality of recording elements comprise plural recording heads which correspond to a number of color components; and

wherein said display means provides a graphic display of correction data for one of the plural recording heads in response to an input third instruction.

29. A method for correcting a non-uniformity in a printing operation performed by plural recording elements arranged in a column, said method comprising the steps of:

printing a predetermined pattern based on an input signal using the plural recording elements;

determining a non-uniformity in the predetermined pattern printed in said step of printing; and

correcting the input signal in accordance with the non-uniformity determined in said step of determining;

wherein the predetermined pattern includes plural rows, the plural rows including a constant density row having upper and lower borders, the constant density row being adjacent to other rows in the plural rows on the upper and lower borders;

wherein the plural recording elements print the predetermined pattern by scanning in a direction of the plural rows; and

wherein, in the determining step, the non-uniformity is determined using a density of the constant density row irrespective of densities of other rows in the predetermined pattern.

30. A method according to claim 29, wherein the plural recording elements eject droplets of liquid; and

wherein the plural recording elements generate thermal energy to eject droplets of the liquid.

31. A method according to claim 29, wherein the plural recording elements are disposed in a plurality of groups, each of the plurality of groups corresponding to one of several different color components.

32. A method according to claim 31, wherein the several different color components comprise cyan, magenta and yellow.

33. A method according to claim 29, wherein said step of determining is performed manually.

34. A method according to claim 29, further comprising the step of binarizing the input signal.

Description Submit all comments and votes

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to an image forming apparatus for forming an image using a recording head having multiple dot recording elements.

In an example of conventional apparatus of this type, an image is read, and the read image is converted to digital signals, which are then processed so that the image is recorded using a recording head having multiple dot recording elements in accordance with the processed data. Such an apparatus is not completely free from the problem that the density of the output image is not uniform due to manufacturing variation of the recording head and/or due to the variation in the materials constituting the recording head. U.S. Ser. No. 271,299 filed on Nov. 15, 1988, now U.S. Pat. No. 5,038,208, assigned to the assignee of this application has proposed that the apparatus is provided with memory means for storing data in accordance with output properties of the individual dot recording elements of the head and means for correcting the input image data in accordance with the stored data to prevent the occurrence of the non-uniform density.

However, in this proposal the correcting data is stored in the memory (ROM) in accordance with the output properties inherent to the recording elements, and therefore, when, for example, the output properties of the dot recording elements changes due to change in the ambient conditions or due to long term use thereof, the recording head has to be exchanged, or the memory (ROM) has to be produced again. This would result in the difficulty in maintaining the image quality after the apparatus is sold and the cost for exchanging parts increases.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention to provide an image forming apparatus wherein the image quality can be maintained even when the properties of dot recording elements change.

It is another object of the present invention to provide an image forming apparatus wherein color imbalance or density non-uniformness can be corrected by easy operation. According to an aspect of the present invention, there is provided an image forming apparatus including correcting means for correcting recording parameters for the dot recording elements constituting a recording head for image formation, display means for displaying the correction provided by the correcting means; input means for changing the correction by the correcting means and means for performing recording operation of a predetermined pattern by the recording head in accordance with the correction changed by said input means.

It is a further object of the present invention to provide an image forming apparatus wherein an operator can easily recognize the corrected state of the density non-uniformness.

It is a further object of the present invention to provide an image forming apparatus wherein the corrected state in the density non-uniformness or color imbalance can be known for individual colors.

It is a further object of the present invention to provide an image forming apparatus in which the image density non-uniformness or the color imbalance can be easily corrected.

These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a digital color copying apparatus according to an embodiment of the present invention.

FIG. 2 shows details of a scanning carriage.

FIG. 3 is a top plan view of an inside of a scanner.

FIG. 4 illustrates a reading operation of the scanner.

FIG. 5 is a block diagram of a control system of the digital color copying apparatus according to an embodiment of the present invention.

FIG. 6 illustrates image information timing between circuit blocks.

FIG. 7 is a block diagram of a color image processing apparatus.

FIG. 8 is a circuit diagram of the system according to a first embodiment.

FIG. 9 shows a correcting table of a correcting ROM.

FIG. 10 shows a display of a liquid crystal touch panel in the operational panel in the first embodiment during the property changing mode.

FIG. 11 shows a pattern signal produced by a pattern generator shown in FIG. 5.

FIG. 12 illustrates a record pattern to be recorded by the recording head in accordance with the pattern signal.

FIG. 13A shows a record pattern in a second embodiment.

FIG. 13B illustrates a problem arising in the case of the record pattern shown in FIG. 12.

FIG. 14 shows a display of a liquid crystal touch panel of an operational panel according to a third embodiment, in a property changing mode.

FIG. 15 shows a fourth example of the record pattern to be recorded by the recording head in the property changing mode.

FIGS. 16 and 17 show other examples of the display shown in FIG. 10.

FIG. 18 is a block diagram which is a modification of FIG. 8 structure.

FIGS. 19 and 20 show further examples of the display of FIG. 10.

FIG. 21 is a flowchart illustrating a correcting operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiments of the present invention will be described in detail in conjunction with the accompanying drawing. In the embodiments, an image forming apparatus of an ink jet recording type is taken as exemplary. In the ink jet recording apparatus taken here, a recording head is provided with multiple nozzles (dot recording elements) for ejecting ink.

[General Description]

Referring to FIG. 1, there is shown a cross-sectional view of a digital color copying apparatus according to an embodiment of the present invention.

The apparatus is generally divided into two parts. A color image scanner is disposed at a top side of the apparatus to read the original image and produce digital color image data, and a controller 2 is contained in the scanner 1 to perform various image processing of the digital color image data and having interface with an external apparatus.

The scanner 1 reads a three-dimensional or sheet original placed face down on a platen below an original cover 11. It is provided with a mechanism 12 for reading a large size sheet original.

An operating station 10 is connected with the controller 2, wherein various instructions for the copying apparatus are input. The controller 2 controls operations of the scanner I and a printer 3 in accordance with the input instructions. When a more complicated adding process or the like is desired, a digitizer or the like is used in place of the original cover 11, and is connected with the controller 2 to permit more complicated image-processing.

The bottom part of the image forming apparatus provides the printer 3 for recording the color digital image signal produced by the controller 2 on a recording sheet. In this embodiment, the printer 3 is of such a type as is disclosed in Japanese Laid-Open Patent Application No. 59936/1979 (ink jet recording type) wherein the liquid is ejected by an application of thermal energy imparting film boiling. In this embodiment, it is a full-color printer.

The above-described two parts are separable, and therefore, they may be disposed at remote positions using a long connecting cable.

In operation, an image of a original placed on an original supporting platen glass 17 or a sheet original fed by a sheet feeding mechanism 12 is read by an exposure lamp 14, a lens 15 and an image sensor 16 (CCD in this embodiment) capable of reading a line of an image in full-color. Then, the scanner 1 and the controller 2 carry out various image-processing, and then, the printer 3 records the image on the recording paper.

In FIG. 1, the recording paper 1 is in the form of cut sheets accommodated in a sheet cassette 20 having a relatively smaller size (A4-A3, in this embodiment) or it is in the form of a roll of paper 29 having a relatively large size (A2-A1, in this embodiment).

A cover 21 of the sheet feed station is constituted as a manual sheet feeding tray by which sheets can be manually fed one by one manually.

A pick-up roller 24 picks one sheet up from the cassette 20. The cut sheet picked up by the roller 24 is conveyed to a first sheet conveying roller 26 by a cut sheet conveying roller 25.

The rolled sheet 29 is fed out by a rolled sheet feeding roller 30, and is cut into a desired predetermined length by a cutter 31 and is conveyed to the first feeding roller 26.

Similarly, the recording sheet supplied from the manual feed tray 22 is conveyed to the first feeding roller 26 by a manual feeding roller 32.

The pick-up roller 24, the cut sheet feeding roller 25, the rolled sheet feeding roller 30, the first feeding roller 26 and the manual feeding roller 32 are driven by an unshown feeding motor (a DC servo motor in this embodiment), and are on-off controlled by an electromagnetic clutches associated with the respective rollers.

When the printing operation is started in response to the instructions from the controller 2, the recording sheet selectively fed from one of the sheet feeding paths is conveyed to the first feeding roller 26. In order to prevent oblique conveyance of the paper, a predetermined amount of loop of the paper is formed by stopping by the first feeding roller 26, and then it is fed to the second feeding roller 27.

During the printing operation by the recording head 37, a scanning carriage 34 on which the recording head 37 or the like is mounted reciprocates by a scanning motor 35 on a carriage rail 36. In the forward stroke of the reciprocation, the image is printed on the recording paper, and in the backward stroke, the recording sheet is advanced by a predetermined increment by a paper feeding roller 28. The recording paper on which the image is printed is discharged onto a discharge tray 23, thus completing the printing operation.

Referring to FIG. 2, the scanning carriage 34 will be described in detail.

A paper feeding motor 40 is a driving source for intermittently feeding the recording paper, and it drives the second feeding roller 27 through a paper feeding roller 28, the second roller and the clutch 43.

The scanning motor 35 is a driving source for scanningly driving the scanning carriage 34 through a scanning belt 42 in directions A and B. In this embodiment, the paper feeding motor 40 and the scanning motor 35 are in the form of a pulse motor, because correct paper feeding control is desired.

When the recording paper reaches the second feeding roller 27, the second roller, the clutch 43 and the paper feeding motor 40 is actuated, by which the recording paper is conveyed on the platen 39 to the paper feeding roller 28.

The recording paper is detected by a paper recording sensor 44 mounted on the platen 39, and the output of the sensor is used for position control and jam clearance.

When the recording paper reaches the paper feeding roller 28, the second roller clutch 43 and the paper feeding motor 40 is deenergized, and then, the recording paper is attracted onto the platen 39 by an unshown sucking motor from an inside of the platen.

Prior to the image recording operation on the recording paper, the scanning carriage 34 is moved to the home position sensor 41, and then, it is moved in the direction A for the forward scanning. From a predetermined position, the recording head 37 ejects droplets of cyan, magenta, yellow and black ink to perform the image recording. After a predetermined length of recording operation is completed, the scanning carriage 34 is stopped, and it is moved in the backward direction, that is, direction B, so that the scanning carriage 34 is returned to the home position sensor 41. During the backward stroke, the paper is fed through a length equal to the length in which the recording head 34 records by the paper feeding roller 28 driven by the paper feeding motor 40 in a direction C.

In this embodiment, the recording head 37 is such that a bubble is formed by heat, and the pressure resulting therefrom is effective to eject a droplet of ink. Four assemblies each having 256 nozzles are used.

When the scanning carriage 34 stops at its home position where it is detected by the home position sensor 41, the recording head recovering operation is performed. This is a processing for stably executing the recording operation. In the recovery operation, pressure is applied to the recording head 37, or the ink is ejected idly, in accordance with programmed conditions determined in accordance with paper feeding time, temperature in the apparatus, ejecting time or the like in order to prevent non-uniform ejection at the initial stage of the ejecting operation attributable to the variation in the viscosity or the like of the ink remaining in the nozzle of the recording head.

By repeating the above described operation, the entire surface of the recording paper is subjected to the image recording operation.

[Scanner]

Referring to FIGS. 3 and 4, the description will be made as to the scanner 1. FIG. 3 illustrates the mechanism in the scanner.

A CCD unit 18 is constituted by CCD 16, a lens 15 or the like and is moved on a rail 54 by a main scan direction driving system including a main scan motor 50 fixed on the rail 54, a Pulley 51, a pulley 52 and a wire 53, so as to read the image of the original on the original supporting glass 17 in the main scanning direction. A light blocking plate 55 and the home position sensor 56 used for the position control when the CCD unit 18 is moved to the main scan home position in a correction area 68 in the Figure.

The rail 54 is on the rails 65 and 65 and is moved by a sub-scan driving system including a sub-scan motor 60, pulleys 67, 68, 71 and 76, shafts 72 and 73 and wires 66 and 70. A light blocking plate 57, home position sensors 58, 59 are used when the rail 54 is moved to the sub-scan home positions in a book mode in which a book original or the like on the platen 17 is read and in a sheet mode in which a sheet original is read, respectively.

The sheet feeding motor, the sheet feeding rollers, the pulleys and the wire constitute a mechanism for feeding the sheet original. This mechanism is disposed on the original supporting platen glass 17, and functions to advance the sheet original placed face down on the platen glass 17 by a predetermined amount at a time by sheet feeding rollers.

FIG. 4 illustrates an original reading operation in the book mode and the sheet mode.

In the book mode, the CCD unit 18 is moved to the book mode home position (book mode HP) in the correction area 68, and from this position, the reading operation of the entire surface of the original plate on the platen 17 is started.

Prior to the scanning of the original, the necessary data setting, such as shading correction, black level correction, color balance correction or the like, is carried out in the correction area 68. Thereafter, the scanning operation in the main-scan direction starts in the direction indicated by an arrow by a scanning mode 50. After the area leading operation (1) is completed, the main scanning motor 51 is reversed, and the sub-scanning motor 60 is driven to move it in the correction area 68 in the sub-scan direction. Then, similarly to the main scan in the area (1), the shading correction, the black level correction, the color balance correction or the like are carried out as desired, and the area (2) is read.

By repeating the above scanning operation, the areas (1)-(7) are read entirely. After the area (7) is read, the CCD unit 18 is returned to the book mode home position.

The apparatus of this embodiment is capable of reading an any size original at maximum, and therefore, a greater number of scanning operations have to be repeated, but they are omitted for the sake of simplicity of explanation.

In the sheet mode, the CCD unit 18 is moved to the shown sheet mode home position (sheet mode HP), and the area (8) is repeatedly read while the sheet original is intermittently advanced by the sheet feeding motor 61, so that the entire sheet original is read.

Prior to the scanning of the original, the shading correction, the black level correction. Color correction or the like are performed by reading reference colors on the correction area 68, and thereafter, the scanning operation in the main-scan is started by the main-scan motor 50 in the direction indicated by an arrow. After the reading operation for the area (8) in the forward stroke, the main-scan motor 50 is reversed. During the returning stroke, the sheet feeding motor 61 is driven to advance the sheet original by a predetermined distance in the sub-scan direction. The same operation is repeated to read the entire sheet original.

If the above reading operation is a one-to-one reading, the area read by the CCD unit 18 is an actually broad area as shown in FIG. 4. This is because the digital color copying machine of this embodiment has a variable magnification function for enlargement and reduction. More particularly, as described in the foregoing, the area covered by one scan of the recording head 37 is fixedly 256 bits, and therefore, when the reduction copy of 50% is to be performed, the image information in the double area, i.e., 512 bits at minimum is required. Therefore, the scanner 1 has a function of reading and outputting in a given image area by one scan.

[Function Block]

Referring to FIG. 5, the function block for the digital color copying machine according to this embodiment will be described.

Controllers 102,111 and 121 control the scanner 1, the controller portion 2 and the printer 3, respectively. They are constituted by a microcomputer or computers, program ROM, data memory and communication circuits and others. The controllers 102 and 111 are connected by communication wiring, and the controllers 111 and 121 are connected by communication wiring. The control system is a so-called master-slave type wherein the controllers 102 and 121 are controlled by the controller 111.

The controller 111 is controlled in accordance with the input to the operation panel 10 and to the digitizer 114, when the apparatus operates as a color copying machine.

The digitizer 114 receives information required for the trimming and masking operation. The digitizer 114 is optionally provided in consideration of the requirement