JP2007144651A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a more accurate image compensation to the oblique motion to be performed, to enable the folding, the deformation and the jamming of a recording medium to be estimated, and to enable the folding and the jamming to be limited to a light degree in an inkjet method printer. <P>SOLUTION: This image forming device is constituted of a means which detects the end section of the recording medium at any time, a means which changes the alignment of an image in response to the degree of the oblique motion, and an estimating means for the recording medium end section. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that has a recording head including a plurality of nozzle rows each including a plurality of nozzles and forms an image by ejecting ink onto a recording medium.

  The present invention can be applied to a general printing apparatus, a facsimile having a copying machine and a communication system, an industrial recording apparatus combined with various processing apparatuses, and a processing apparatus such as a printing apparatus and an etching apparatus. It can also be applied to.

  2. Description of the Related Art As information output devices in word processors, personal computers, facsimiles, and the like, printers that record information such as desired characters and images on a sheet-like recording medium such as paper or film are widely used.

  Various types of recording methods are known for printers, but inkjet methods have recently been used for reasons such as non-contact recording on recording media such as paper, easy colorization, and high quietness. It has attracted particular attention, and as its configuration, a serial head that performs recording while mounting a recording head that ejects ink according to desired recording information and reciprocating scanning in a direction perpendicular to the feeding direction of a recording medium such as paper In general, the recording method is widely used because it is inexpensive and easy to downsize.

  In recent years, personal computers have become widespread, and the opportunity to record high-definition and high-quality images such as photographs has increased. Therefore, there is a demand for an inexpensive and inexpensive image forming apparatus that can be handled by anyone.

In order to provide an inexpensive image forming apparatus in which a recording head having a plurality of nozzles for ejecting ink reciprocates on the recording medium to form an image, it is inevitable to convey the recording medium to a certain degree. It has become. In that case, when the recording medium is conveyed while being skewed as disclosed in Japanese Patent Laid-Open No. 5-22992, the skew is mechanically corrected. In addition, if the recording medium is damaged due to deformation of the recording medium or a jam, etc., the recording medium may malfunction if the recording medium is stopped in a portion where there is no recording medium, and ink for image formation may be ejected. In some cases, the recording medium enters the part, and the recording medium enters the part and cannot be removed.
Japanese Patent Laid-Open No. 5-22992

However, in the above conventional example,
(1) When ink is ejected to a portion where there is no recording medium, the ink adheres to the parts underneath, and when printing is performed on a normal recording medium without dirt, the ink attached to the parts is transferred to the recording medium, and the output product In some cases, the recording medium is soiled.

  (2) When ink is ejected to a portion where there is no recording medium, ink is deposited on the component underneath, and even if an attempt is made to remove the ink from that component, the configuration is inexpensive and the user must manually clean it. was there.

  (3) When the recording medium is skewed, an image may be formed obliquely on the output recording medium.

  The present invention has been made in view of the above situation, and by measuring the edge of the recording medium in real time during image formation, the degree of skew of the recording medium is measured, and image formation that matches the degree is performed. It is an object to provide a high-definition image forming apparatus by performing in real time.

  In addition, it detects whether or not there is a recording medium on the recording head in real time during image formation, and if the predicted recording medium edge and the actual recording medium edge are different, ink ejection for image formation is stopped. Accordingly, an object of the present invention is to provide an image forming apparatus that can be easily used by anyone while avoiding ink ejection to components.

  In order to achieve the above object, an image forming apparatus according to the present invention is configured as follows.

In an image forming apparatus for forming an image by a recording head mechanism including a plurality of nozzle rows in which nozzles for ejecting ink are arranged in a row,
A means for detecting the end of the recording medium as needed and a means for changing the arrangement of images according to the skew;
Means is provided for detecting the edge of the recording medium at any time during image formation, detecting the skew of the recording medium from the position of the edge, and correcting the image ejection data diagonally in real time. Also,
When the edge of the recording medium currently scanned at the time of image formation is different from the edge of the recording medium estimated from the previous scanning, means for stopping image formation is provided.

  As described above, according to the present invention, the position of the edge of the recording medium is always detected, and the image alignment is changed in consideration of the skew of the recording medium in real time, so that more accurate image correction for skew is performed. Can be done. Further, the difference between the prediction of the edge of the recording medium and the detection of the actual edge can predict the folding / deformation or jam of the recording medium, and can be limited to a slight fold or jam.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  FIG. 1 is a block diagram illustrating a configuration of an electric circuit of the image forming apparatus according to the present exemplary embodiment. In FIG. 1, 10 is a memory unit composed of a non-volatile memory such as a ROM and a volatile memory such as a RAM, a part storing programs necessary for the operation of 11 CPUs, and 12 communications. It is used as an image buffer for primarily storing image data sent through the unit, a work area for each processing circuit, and a spool buffer area for outputting an image to the recording head. Reference numeral 11 denotes a CPU that performs all the controls of the image forming apparatus. This CPU controls all of the image forming apparatus by setting appropriate values in the registers built in the respective circuits in accordance with the program stored in 10. Reference numeral 12 denotes a circuit for detecting the end of the recording medium on the recording head mechanism. When the end is detected, an interrupt signal is generated for 11 CPUs, and the position of the recording head mechanism at that time is stored. A unit 13 controls communication such as LAN, IEEE 1284, USB, and the like, and is a unit that controls communication of data, particularly image data, between the image forming apparatus and a host computer. Reference numeral 14 denotes an image processing circuit, which is a circuit block for processing the sent image data so that the recording head can form an image on the recording medium. For example, image data sent in RGB multi-value is converted into binary recording ink color, and image processing such as changing the hue or improving the fixing property, and rearranging the image data so as to match the head arrangement order Perform image processing. At the time of rearrangement at this time, the shift of the skew is corrected. Further, every time the 17 recording head moves, 20 encoder sensors sense the movement, and in synchronization with the movement, image data matched with ink to be ejected by the recording head is received from a predetermined address of 10 memories by the CPU. Without using the image data DMA circuit, the data is read out and sent to the 17 recording head mechanism. 15 is a mechatronics control circuit that controls a motor for transporting the recording medium, a motor for moving the recording head, an encoder sensor for counting the amount of movement thereof, a sensor for detecting the entry and ejection of the recording medium, and the like. It is. Reference numerals 18 and 19 denote motors typified by stepping motors and DC motors, which use 17 gears, gears, belts, and the like to move 17 recording heads and transport recording media, respectively. Reference numeral 20 denotes an encoder sensor mounted on the recording head for detecting how much the 17 recording heads have actually moved. An encoder with a slit is arranged along the movement of the recording head. Is read by 20 encoder sensors, and the actual amount of movement is read by counting how many slits have been crossed. Reference numeral 16 denotes a plurality of sensors placed on the conveyance path of the recording medium, which is a circuit for grasping where the recording medium is located from time to time. Reference numeral 16 denotes a display circuit represented by an LCD or the like for giving an error message to a user who uses the image processing apparatus, and displays a message to the user in a timely manner. Reference numeral 1 denotes a communication cable represented by a LAN cable or a USB cable. Reference numeral 2 denotes a communication internal bus for connecting 10 to 16, which is composed of addresses, data, and signal lines for controlling them. 3 is asserted when the end of the recording medium is detected by an interrupt signal output from 12 recording medium end detection circuits to 11 CPUs.

  2A, FIG. 2B, and FIG. 2C are electrical configuration diagrams of the recording medium edge detection of 12 in FIG. FIG. 2A is a diagram of the end detection unit viewed from below. 30 and 31 are light emitting elements such as LEDs. Reference numerals 33 and 34 denote optical sensor ICs that convert the intensity of light taken to a voltage. 30 and 33 form a pair, and 31 and 34 form a pair. This detection circuit is on the recording head mechanism and reciprocates in the direction indicated by 32. FIG. 2B is a cross-sectional view of the end detection portion taken along line 35 in FIG. 2A. Reference numeral 40 denotes a light beam of 30 light emitting elements, 41 denotes a light receiving range of 33 photosensor ICs, and 42 denotes a position of the recording medium. Reference numeral 43 denotes a platen that supports the recording medium 42 and is painted in a color that easily absorbs light. FIG. 2-c shows an electrical configuration of the end detection unit. 30 and 31 are light emitting elements as in FIG. 2A, and 33 and 34 are also optical sensor ICs. 52 to 55 are resistors for dividing the voltage and have the same resistance value. 56 and 57 are comparators that compare two inputs and indicate which voltage is higher, and 58 is an exclusive NOR circuit that determines whether the two inputs have the same logic. The output 100 of the 33 photosensor ICs is compared with the output of the 34 photosensor ICs by 101 by dividing the voltage by the resistors 54 and 55 by the comparator 56. When the voltage of 100 is higher High logic is output to signal 102. A signal output from the optical sensor IC 34 is also a circuit similar to the optical sensor IC 33. When the amount of light received by the optical sensor ICs 33 and 34 is more than doubled in this circuit configuration, a positive logic is output from 103. In FIG. 2A, when 33 is a recording medium below 30 and 33 and reacts brightly, when there is no recording medium below 31 and 34 and reacts darkly, it is detected that it is the end of the recording medium, and 103 Outputs positive logic. FIG. 3 shows image data positions to be read in real time depending on the skew of the recording medium. Reference numerals 60 and 61 denote lengths corresponding to the width of one nozzle row on the recording head of the image data placed on the memory. Here, the width is 256 bits. 62 and 63 are image data having a length corresponding to 1 bit horizontally and 100 bits vertically, 64 is image data having a length corresponding to 1 bit horizontally and 56 bits vertically, 65 is image data having a length corresponding to 1 bit horizontally and 100 bits vertically, and 66 is horizontal data. The image data has a length corresponding to 1 bit and 156 bits. FIG. 4 is a diagram in which the recording head mechanism reciprocates on the recording medium. Reference numerals 70 and 78 denote recording head mechanisms, reference numerals 71, 72, 73, 74, and 76 denote end parts of the recording medium, and reference numeral 75 denotes an end part position of the recording medium estimated from 71 to 74. Reference numeral 79 denotes the shape of the recording medium. This embodiment will be described with reference to the flowchart of FIG. This flowchart is executed under the control of 11 CPUs. In step S1, the communication i / F circuit 13 controls the image forming apparatus of this embodiment to receive image data from the host computer connected by the communication cable 1, and store the image data in the memory 10. In S2, the skew of the recording medium is calculated from the end position of the recording medium detected by the previous reciprocation of the recording head, and the image position to be read is calculated. When the head is at position 78, the end of 74 recording media is detected by the previous scan of the recording head. The skew rate is calculated from the recording edge positions 73 and 74 detected in the previous scan, and the image data is read from the positions 65 and 66 on the memory 10. In S3, the image data read in S2 is transferred to the 17 recording heads and ink is ejected in synchronization with the movement of the recording head mechanism using the 18 motor. In S4, it is determined whether the recording medium edge detection circuit 12 on the recording head mechanism has detected the edge of the recording medium. If detected, the signal 103 changes to positive logic. If the end of the recording medium is detected, the process proceeds to S5. If not detected, the process returns to S2. In S5, it is determined whether or not the position of the edge detected in S4 is significantly different from the expected position. If the end positions 72, 73, 74 to 75 are predicted but the actually detected end position is 76, the end position of the recording medium is different from the expected position, and the process proceeds to S10. If it is as expected, the process proceeds to S6. In S6, it is determined whether or not ink ejection for forming an image has been completed. When all the discharges are completed, the process proceeds to S11. If all the ejections are not completed, the process proceeds to S7, and the skew of the next scan is calculated from the end position of the recording medium detected in the previous scan. Proceeding to S8, the prediction of the end position of the recording medium in the next scan is calculated from the end position of the recording medium detected in the previous scan. Proceeding to S9, the recording medium is line fed by an appropriate amount using 19 motors. In S10, a message is displayed on the 16 display devices because there is a possibility that the jam or the recording medium is broken because the end position of the expected recording medium is different from the actual end position of the recording medium. In S11, the entire recording medium is discharged using the motor 19 and the present embodiment is finished.

  By repeating such processing, the end position of the recording medium can be detected in real time, and image data at a position corresponding to the skew of the recording medium can be read and discharged in real time. In addition, when the recording medium edge position is different from the expected and actual, it is assumed that an abnormality has occurred in the recording medium, and by stopping the image formation, the jam of the recording medium is deteriorated or the ink on the portion without the recording medium is detected. Discharge can be avoided.

FIG. 2 is a block diagram illustrating a configuration of an electric circuit of the image forming apparatus used in the first embodiment. (A) The figure which sees the electricity of recording-medium edge part detection from the bottom in Example 1, (b) The figure which sees the cross section of the line shown by 35 of FIG. c) The electrical configuration of the end detector. The image data position to be read is shown according to the skew of the recording medium. FIG. 3 is a diagram in which a recording head mechanism reciprocates on a recording medium. 3 is a flowchart used for explaining the first embodiment.

Claims (2)

A mechanism for receiving image data, a memory mechanism for storing the received image data, a recording head mechanism having a plurality of nozzle arrays in which nozzles for ejecting ink are arranged in a line, a mechanism for moving a recording medium and the recording head, , Means for detecting in real time whether there is a recording medium on the recording head mechanism, and ejecting ink from the nozzles of the recording head according to the image data stored in the memory mechanism while moving the recording head at any time In an image forming apparatus for forming an image on a recording medium,
An image forming apparatus characterized by detecting an edge of a recording medium at any time during image formation, detecting a skewing degree of the recording medium from the position of the edge, and correcting the image ejection data obliquely in real time. A mechanism for receiving image data, a memory mechanism for storing the received image data, a recording head mechanism having a plurality of nozzle arrays in which nozzles for ejecting ink are arranged in a line, a mechanism for moving a recording medium and the recording head, , Means for detecting in real time whether there is a recording medium on the recording head mechanism, and ejecting ink from the nozzles of the recording head according to the image data stored in the memory mechanism while moving the recording head at any time In an image forming apparatus for forming an image on a recording medium,
An image forming apparatus characterized in that image formation is stopped when a recording medium edge currently scanned at the time of image formation is different from a recording medium edge estimated from previous scanning.

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