JP2017016010A - Image forming apparatus, control method of the same, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of cracks in an image at a rear end of a recording medium.SOLUTION: An image forming apparatus draws out and feeds, from a roll sheet supply part 20, any one of roll sheets 21A to 21C that are long recording media wound in a roll state; cuts the roll sheet into a predetermined length with a cutting device 40; conveys the cut recording medium piece with a conveyance roller 71 or the like; and forms an image for each one of pages with an imaging process part 30 or the like. The image forming apparatus records, of image information for forming the image for each one of pages, information on pixels for forming an image at least in a predetermined area at a rear end of the image, and when the stored information on the pixels is equal to or more than a preset value, changes the position to cut the roll sheet to extend the length of the recording medium piece.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus, a control method therefor, and a program.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, an image is formed by image data obtained by reading a document or image data transmitted from an external device, and a long recording medium (hereinafter referred to as “roll paper”) wound in a roll shape. A technique for transferring the image is known. Normally, this type of image forming apparatus includes a cutter mechanism (cutting device) for cutting roll paper, and cuts the roll paper according to the image size for forming an image for each page.

  For this reason, for example, in Patent Document 1, the number of pulses for feeding roll paper is calculated based on the number of line image data of a document read by a reading line of a document reading unit, and the number of pulses is calculated based on the number of pulses. A technique for accurately cutting roll paper is disclosed.

  However, in such a conventional image forming apparatus, the image at the rear end may be missing. Specifically, in order to stabilize the conveyance of the roll paper as the recording medium, the recording medium is conveyed while being pulled, so that the amount of roll paper fed out from the paper feeding unit varies and the cutting position of the recording medium is changed. Variation occurs. Further, when the registration shift at the leading edge of the recording medium occurs, the image position to be transferred is displaced.

If the rear end of the recording medium passes through the transfer position before the rear end of the image due to such a variation in the cutting position of the recording medium or the deviation of the image position, the image at the rear end is not transferred to the recording medium and the image is missing. The problem that occurs occurs.
The present invention has been made to solve such a problem, and an object of the present invention is to prevent image missing from occurring at the rear end portion of a recording medium.

  The image forming apparatus according to the present invention feeds and feeds a long recording medium wound in a roll shape, cuts the recording medium into a predetermined length, and cuts the recording medium piece for each page. In order to achieve the above object, image formation is performed at least in a predetermined area at the rear end of the image among the image information for forming the image for each page. Storage means for storing information on the pixels to be recorded, and when the information on the pixels stored in the storage means is equal to or greater than a preset value, the recording medium piece is elongated at a position to cut the long recording medium. And a cutting position changing means for changing to the above.

  According to the present invention, it is possible to prevent image missing at the rear end of the recording medium.

1 is a mechanism diagram illustrating an overall configuration of an embodiment of an image forming apparatus according to the present invention. FIG. 2 is an enlarged view of an image forming process unit 30 in FIG. 1. FIG. 2 is a block diagram illustrating a configuration of a main part of a control system in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a block diagram showing the writing unit 33 in FIG. 1 with an LED writing control circuit 330 as a functional block configuration. 5 is a flowchart showing a basic example of a processing flow according to the present invention when the image forming apparatus shown in FIGS. 1 to 4 performs printing. 6 is a flowchart illustrating a processing flow of an embodiment in which processing for adjusting a correction value for a paper length according to environmental changes is added to the processing in FIG. 5. It is a flowchart which shows the flow of the process regarding image data accumulation | storage in embodiment which has image input / output parallel operation mode which writes in during image accumulation | storage. It is a flowchart which similarly shows the flow of the process regarding writing.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 1 is a block diagram showing an outline of a mechanism part of a copying machine which is an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing details of the image forming process part.
The image forming apparatus shown in FIG. 1 includes a document reading unit 100 that reads an image of a document on an upper part of a main body 200 that is an image forming unit (plotter unit). An operation panel 402 of the unit 400 is provided.

This image forming apparatus has at least a function as a copying machine for copying and printing an image of a document. However, it can also be used as a printer that receives print data from an external host device and prints it, a scanner that reads an image of a document and sends out the image data, or a facsimile device, and can also be a digital multifunction device. .
The document reading unit 100 is also referred to as a scanner unit. A document feeding roller 11, an opposing contact sensor 12 and a white roller 13, and a pair of document discharge rollers 14 are arranged along an internal document transport path following the document table 10. 15 and a switching claw 16 are arranged.

When the start key on the operation panel is pressed while the document is inserted and set on the document table 10 with the image surface facing upward and the leading end thereof reaching the document feed roller 11, The original is conveyed rightward in FIG. 1 by the rotation of the original feeding roller 11.
When the original passes between the contact sensor 12 and the white roller 13, the image surface is irradiated by a light emitting diode (LED) provided in the contact sensor 12, and the reflected light from the image surface is reflected in the built-in lens. An image is formed on the light receiving element by the element. Thereby, the image information of the original is read and converted into an electric signal. The processing of the electric signal will be described later with reference to FIG.

  The document whose image has been read is conveyed by the document discharge roller 14, and when the switching claw 16 is in the horizontal position shown in FIG. 1, it is sent to the straight discharge path 17A and is not shown on the right side in the figure. The document is discharged onto the document discharge tray. When the switching claw 16 is moved to an upwardly inclined position, the document on which the image has been read is sent to the reverse discharge path 17B and further conveyed by the document discharge roller 15, and the upper document discharge tray 18 is moved. To be discharged.

  According to the document reading unit 100, an image of a document fed by the document feeding roller 11 can be read. For this reason, a sensor group 19 is provided in the document transport mechanism, and the sensor group 19 can detect the length of the document in the feeding direction and the document width which is the size in the direction orthogonal thereto. Accordingly, it is possible to automatically select the width of a roll paper, which will be described later, used when printing the image of the original, or to determine the required length for cutting the roll paper.

The operation unit 400 has an operation panel 402 provided with an input unit for an operator (user) to perform various settings and a display unit for displaying various types of information at a position where it can be easily operated and viewed from the outside. An operation control circuit 401 (to be described later) is provided therein.
A liquid crystal display panel (LCD) is generally used as the display unit of the operation panel 402, and not only mechanical keys and switches but also a transparent touch panel arranged on the liquid crystal display panel is used as the input unit. Touch keys and the like are also included.

  The main body 200 is an image forming unit (plotter unit) that forms an image of a document on a recording medium, and a roll paper supply unit 20, an image forming process unit 30, a cutting device 40, a fixing device 60, Various rollers constituting the recording medium transport mechanism are provided. In addition, although various drive mechanisms and motors, a control unit for controlling them, a power supply unit, and the like are also provided, general configurations not directly related to the present invention are not shown. Portions relating to the present invention in the control unit and the like will be described later with reference to FIG. Casters 202 are attached to the four corners of the lower surface of the casing 201.

  The roll paper supply unit 20 holds three types of roll papers 21A, 21B, and 21C, which are long strip-shaped recording media wound in a roll shape, on a support shaft 22 so as to be rotatable, and each predetermined position. The storage is arranged. As roll papers 21A, 21B, and 21C, papers with different widths such as those for A3 and A4 sizes and B4 and B5 sizes are often set, but roll papers with different colors and thicknesses are set. You can also

  The roll paper 21A drawn out from the roll paper supply unit 20 is fed out by a pair of feed rollers 23 and directed toward a pair of transport rollers 71 arranged on the downstream side of the feed rollers 23 in the roll paper transport path. Are transported. The roll paper 21 </ b> B is fed by the pair of feeding rollers 24 and is further conveyed toward the conveying roller 71 by the pair of paper feeding / conveying rollers 26. The roll paper 21 </ b> C is fed out by the pair of feeding rollers 25 and further conveyed toward the conveying roller 71 by the pair of paper feeding / conveying rollers 27.

One of the roll papers 21A, 21B, and 21C is selected and fed out. In the following description, when the roll papers 21A, 21B, and 21C are not particularly distinguished, they are simply referred to as “roll paper”. Each of the feeding rollers 23 to 25, the paper feeding and conveying rollers 26 and 27, and the conveying roller 71 described above rotate so as to convey the roll paper at the same speed.
A rotary-type cutting device 40 is disposed in the conveying path between the feeding roller 23 and the sheet feeding and conveying rollers 26 and 27 and the conveying roller 71. The cutting device 40 cuts the roll paper while the feeding roller 23 or the paper feeding / conveying roller 26 or 27 and the conveying roller 71 are both conveying the roll paper at a constant speed. The cut (cut) roll paper is referred to as a recording medium piece. This corresponds to general transfer paper.

In addition, a tip detection sensor 41 is disposed in the conveyance path between the cutting device 40 and the conveyance roller 71. Then, from the time when the leading edge of the roll paper is detected by the leading edge detection sensor 41, the conveyance amount is measured by a pulse signal corresponding to the rotation amount of the conveyance roller 71 from the drive control circuit of the conveyance roller 71. When the transport amount reaches a specified length according to the document size, the rotary cutter of the cutting device 40 is operated to cut the roll paper. As the tip detection sensor 41, a reflection type or transmission type photosensor may be used.
The cut (cut) recording medium piece is then further conveyed by the conveying roller 71 to a position where it abuts against a pair of positioning rollers (also referred to as registration rollers) 72, where it is stopped once.

An image forming process unit 30 is disposed on the downstream side of the positioning roller 72.
The image forming process unit 30 is provided with a drum-shaped photoconductor 31 as a latent image carrier as shown in FIG. A charger 32, a writing unit 33, a developing device 34, a transfer roller 35, a P sensor 36, a cleaning device 37, a static eliminator 38, and the like are sequentially arranged around the photoconductor 31 along the rotation direction. ing.

In the image forming process unit 30, the outer peripheral surface (surface) of the photoconductor 31 rotating in the direction indicated by the arrow D is uniformly charged by the charger 32, and then the image information for one page is written by the writing unit 33. In accordance with the above, light is sequentially irradiated and exposed. Thereby, an electrostatic latent image is formed on the surface of the photoreceptor 31. When copying an image of an original, image data of the original read by the original reading unit 100 is the image information. Details of the writing unit 33 will be described later with reference to FIG.
Next, the developing device 34 supplies toner to the electrostatic latent image and develops it to form a toner image.

  On the other hand, in accordance with these timings, a roll of paper is fed from the roll paper supply unit 20 of FIG. 1, and the recording medium piece cut by the cutting device 40 and conveyed to the positioning roller 72 is fed to the photosensitive member 31 at a predetermined timing. And the transfer roller 35. Therefore, the toner image on the photoreceptor 31 is transferred onto the transfer paper by the transfer roller 35.

A fixing device 60 is disposed on the downstream side of the image forming process unit 30, and the recording medium piece carrying the toner image is conveyed to the fixing device 60. When the recording medium piece passes through the fixing device 60, it is heated and pressed at the nip portion between the fixing roller 61 and the pressure roller 62 to fix the carried toner image, and a series of image forming processes is completed. To do.
On the other hand, after the toner image is transferred to the recording medium piece, the residual toner remaining on the surface is removed by the cleaning device 37 and the charge is removed by the charge eliminator 38 to prepare for the next image formation.

In this image forming apparatus, a density detection toner pattern is created outside the image forming area on the photoconductor 31 at a predetermined timing, and the density of the toner pattern is detected by the P sensor 36. A means for controlling the image forming conditions based on the detected density is also provided, whereby the image density can be stabilized.
Further, a temperature / humidity sensor 80 is disposed in the main body 200 (inside the apparatus), and the transfer state is stabilized based on temperature / humidity information detected thereby.

After the image formation is completed, the transfer paper is sent to the straight paper discharge path 76A or the reverse paper discharge path 76B by the pair of paper discharge rollers 73 or 74 and the switching claw 75, and is shown on the right side in FIG. The paper is discharged to a paper discharge tray that is not present or an upper paper discharge tray 203.
As described above, this image forming apparatus feeds and feeds a long recording medium wound in a roll shape, cuts the recording medium into a required length, and adds 1 to the cut recording medium piece. An image forming apparatus that forms an image for each page.

Next, the main part of the control system in this image forming apparatus will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of a main part of the control system.
The image forming apparatus includes a document reading unit 100 as a reading unit that reads a document, an image information storage unit 300 as a storage unit that stores read image information, and an electrostatic latent image on a photosensitive member based on the stored image information. A writing unit 33 is provided for forming an image.

Further, a system control unit 500 and a drive control circuit 510 that control these and execute a series of processes, and a printer driving device 520 that drives each unit in the main body 200 described above are also provided.
The system control unit 500 also exchanges signals and data with the operation unit 400 described above.
The operation unit 400 includes an operation control circuit 401 that performs display control of the operation panel 402, detection of an input operation, and the like.

  The document reading unit 100 converts an image of a document into an electrical signal by the contact sensor 12 also shown in FIG. 1, and an image amplification circuit 102, an A / D conversion circuit 103, and a shading correction circuit for processing the electrical signal. 104 and an image processing circuit 105 are provided. Further, a synchronization control circuit 106 and a reading control circuit 107, and a scanner driving device 108 for driving the document reading unit 100 including the document feeding roller 11 and the document discharge rollers 14 and 15 shown in FIG. .

The contact sensor 12 is abbreviated as CIS, and is formed into a rod shape by arranging a number of light source LEDs, light receiving lenses, and CMOS image sensors in a single row to form an image of each line over the entire width of the original. Convert to an electrical signal (analog signal).
The analog signal is amplified by the image amplification circuit 102. The amplified analog signal is converted into a multi-value digital image signal for each pixel by the A / D conversion circuit 103. The converted digital image signal is corrected by a shading correction circuit 104 that operates in synchronization with a clock signal output from the synchronization control circuit 106 to correct distortion due to unevenness in light amount, contact glass contamination, sensor sensitivity unevenness, and the like.

The corrected digital image information is converted into digital recording image information by the image processing circuit 105, and then written and stored in the image memory unit 310 of the image information storage unit 300.
The image information storage unit 300 includes a plurality of image memory units 310, and the document reading unit 100 sequentially writes digital image information obtained by reading a document image page by page into each image memory unit 310.
In the case of color reading, digital image information of each color component such as R, G, and B is written in each image memory unit 310 for each page.

Next, a system control unit 500 and a writing unit that control a series of processes for forming an image on a recording medium piece based on digital recording image information written in the image memory unit 310 of the image information storage unit 300 The configuration and operation of 33 will be described.
The system control unit 500 includes a CPU that is an arithmetic processing unit, a microcomputer that includes a ROM that is a program memory and a RAM that is a data memory, and has a function of performing overall control of the image forming apparatus.

  The system control unit 500 directly controls the reading control circuit 107 and the synchronization control circuit 106 of the document reading unit 100 and controls the scanner driving device 108 via the drive control circuit 510 to convey the document and its image. Smooth reading of Further, each image memory unit 310 of the image information storage unit 300 is controlled so that digital recording image information (image data) based on the read image information sent from the document reading unit 100 is written in the image memory unit 310. Save temporarily.

The system control unit 500 also controls the transfer of image data from the image memory unit 310 to the LED write control circuit 330 of the writing unit 33, and controls the printer driving device 520 via the drive control circuit 510. To do. The printer driving device 520 is rotated by a cutter motor 540 that drives the cutter of the cutting device in the main body 200 shown in FIG. 1, and each roller that feeds and feeds the roll paper, conveys the cut recording medium piece, and the like. A conveyance motor 570 to be moved, a tip detection sensor 41, and the like. Furthermore, each unit of the image forming process unit 30 and the fixing device 60 are naturally included.
Under the control of the printer driving device 520, the roll paper is fed and fed, cut and smoothly transferred to the recording medium piece, the image forming process unit 30 forms an image, and the toner image is transferred to the recording medium piece. The fixing by the fixing device 60 is smoothly executed.

  A conveyance motor 570 of the printer driving device 520 rotates the conveyance roller 71 and the like shown in FIG. 1 by a pulse signal from the drive control circuit 510. Then, after the leading edge detection sensor 41 outputs a signal that detects the leading edge of the roll paper to the drive control circuit 510, the cutter motor 540 is driven when the pulse signal reaches a predetermined number of pulses corresponding to the paper length. Then, the roll paper is cut into a required length by the cutting device 40.

  Digital recording image information (image data) is input to the writing unit 33 from the image memory unit 310 of the image information storage unit 300. As for the flow of the image data, 2-pixel 1-pixel binary image data having a pixel density of 600 dpi is sent from the image memory unit 310 to the LED writing control circuit 330 simultaneously with a transfer reference clock. The image data sent in parallel by two pixels is once combined into one line inside the LED writing control circuit 330. Then, one pixel of 600 dpi is converted into 4-pixel image data of 1200 dpi, then assigned to 3 divisions, and 4 pixels are simultaneously transferred to LED print heads (hereinafter abbreviated as “LPH”) 33A, 33B, 33C. To do.

Here, the system up to the image information storage unit 300 has been established in the past, and after the input to the writing unit 33, the joint processing is performed in the LED writing control circuit 330, thereby providing versatility. Can do. Further, since the LED print head over the main scanning length of the image forming area is constituted by the three relatively short LPHs 33A to 33C, there is a cost merit.
The LPH is an elongated print head in which a large number of small light emitting diodes (LEDs) are arranged in an array and light is applied to a photoconductor to write an image. The LPHs 33A to 33C are configured by connecting three LPHs in a staggered manner to constitute one print head as a whole.

Next, details of the writing unit 33 in FIG. 1 will be described with reference to FIG. FIG. 4 is a block diagram showing the writing unit 33 in FIG. 1 with the LED writing control circuit 330 as a functional block configuration.
As shown in FIG. 4, the LED writing control circuit 330 includes an image memory control unit 331, a density conversion processing unit 332, an image data thinning processing unit 333, a data division control unit 334, a lighting time control unit 335, a lighting control unit 336, and The storage unit 337 has a functional configuration.

The image memory control unit 331 converts the signal transmitted from the image information storage unit 300 into a gate signal / image data, and rearranges the signal for each line.
In the density conversion processing unit 332, an image of 200 dpi to 600 dpi is input for each line, so that the density conversion processing unit 332 converts the image data to 1200 dpi which is LPH resolution.
When the toner save mode is selected, the image data thinning-out processing unit 333 performs a process of thinning out images according to an instruction from the system control unit 500.
The data division control unit 334 divides the image data into three LPHs. The divided image data is transferred to the LPHs 33A, 33B, and 33C through the lighting time control unit 335 and the lighting control unit 336.

On the other hand, the light quantity data (data on the average light quantity of individual LED elements constituting the LED array included in one LPH) stored in each LPH 33A, 33B, 33C is read from each LPH 33A, 33B, 33C when the power is turned on. And stored in the storage unit 337. The light amount data is read by the lighting time control unit 335 and transferred to the system control unit 500.
The lighting control unit 336 lights the LEDs of the LPHs 33A, 33B, and 33C according to the lighting time, thereby irradiating the charged surface of the photoconductor 31 shown in FIGS. A corresponding electrostatic latent image is formed.

Further, in the system control unit 500, lighting is performed from the light amount data stored in the storage unit 337 in accordance with the toner density (voltage value) obtained by reading the density detection toner pattern by the P sensor 36 illustrated in FIGS. The time is calculated and transferred to the lighting time control unit 335.
Further, the image information storage unit 300 or the image memory control unit 331 is provided with a pixel count unit that stores the number of pixels in the main scanning direction for each sub-scanning line. Then, the number of pixels of the input image data is sequentially counted (FIFO processing), and after the input of the image data is finished, pixel count values for a predetermined number of lines are stored.

For example, when the predetermined number of lines is 10 lines, the above-described pixel count unit is provided with a memory for 10 lines, and if the pixel count value for 10 lines from the rear end of the image is equal to or greater than a predetermined value (for example, 1) Judge as an image.
The number of sub-scanning lines in the pixel count unit and the pixel count value (the predetermined value) in the main scanning direction that is determined to be an effective image can be set to any value within a specific range.

  When using this image forming apparatus, first, the operator selects various modes such as roll paper (paper type and paper size) fed from the operation panel 402 of the operation unit 400 and a tray destination for paper ejection. When a document is set on the document reading unit 100, document setting information is notified from the document reading unit 100 to the system control unit 500. The system control unit 500 notifies the control unit such as the document reading unit 100, the image information storage unit 300, and the writing unit 33 of information necessary for printing.

  Similarly, various modes such as a roll paper (paper type and paper size) to be fed and a tray destination to be ejected can be selected by an operation from an external device such as a personal computer, and the print request is sent to the system controller 500. Be notified. Then, the system control unit 500 notifies the control units such as the document reading unit 100, the image information storage unit 300, and the writing unit 33 of information necessary for printing.

The processing according to the present invention when printing is performed by the above-described image forming apparatus will be described with reference to FIG.
FIG. 5 is a flowchart showing a basic example of the flow of processing according to the present invention when the image forming apparatus shown in FIGS. 1 to 4 performs printing. This process is mainly executed in accordance with control by a system control unit 500 including a microcomputer.

As described above, when a document is set on the document reading unit 100 or a print request from an external device is notified to the system control unit 500, the system control unit 500 starts the processing shown in FIG.
First, in step S101, it is determined whether or not there is a print request. If it is determined that there is no print request, the process waits in step S102 and repeats the loop returning to step S101 to wait for the print request.

If a print request from an external device is notified to the system control unit 500 and started, the determination in step S101 is of course “print request is present”. Therefore, the process immediately proceeds to step S103, and operation mode information necessary for image storage is obtained. To get.
When document setting information is notified from the document reading unit 100 to the system control unit 500 and the system control unit 500 is started, the system control unit 500 determines that “print request is present” in response to a notification that the operator has pressed the start key of the operation panel 402. to decide. Thereafter, the process proceeds to step S103, and operation mode information necessary for image storage is acquired.

After obtaining the operation mode information in step S103, accumulation of image data is started in step S104. In step S105, the pixel count unit of the image information storage unit 300 in FIG. 3 starts counting the number of pixels of the pixel data. Accordingly, the number of pixels of the pixel data in the main scanning direction is counted for each line synchronization signal (each line) in the image data input to the image information storage unit 300 shown in FIG. Is done.
Then, the system control unit 500 waits until it is determined in step S106 that image data accumulation has ended. During the image data storage operation up to that point, the pixel count unit sequentially updates the pixel count in step S107 to hold pixel count information for a predetermined number of lines.

The pixel count unit is a pixel count unit, and the image information storage unit 300 having the pixel count unit forms an image in at least a predetermined region at the rear end of the image among image information for forming an image for each page. It fulfills the function of storage means for storing pixel information to be stored. The predetermined area at the rear end of the image can be an area for predetermined lines (for example, three lines) in which the sub-scanning position of the rear end of the image is sequentially different.
If the system control unit 500 determines in step S106 that image data has been stored, the process proceeds to step S108, and pixel count information for a predetermined number of lines held in the pixel count unit is read.

Thereafter, the system control unit 500 acquires information necessary for the printing operation in step S109, and determines in step S110 whether there is a valid image based on the read pixel count information. Here, when the count value of the pixel count information is equal to or larger than a predetermined value set in advance, it is determined that there is a valid image. If it is determined that there is a valid image, a correction value is added to a predetermined paper length (cut length) in step S111.
When the processing of steps S108, S110, and S111 by the system control unit 500 is greater than or equal to a preset value of pixel information stored in the storage unit, the position at which the long recording medium is cut is indicated by the recording medium piece. This corresponds to the function of the cutting position changing means for changing the length to be longer.

In step S112, a predetermined number of pulses to be fed is calculated based on the selected paper size or the paper size determined by the original size detected by the original reading unit 100 and the correction value, and the selected roll paper Start feeding paper.
When the leading edge of the roll paper is detected by the leading edge detection sensor 41 shown in FIGS. 1 and 3 after the start of paper feeding, the system control unit 500 outputs image data from the image information storage unit 300 in step S113 and writes it. The writing operation by the unit 33 is started.

Thereafter, the system control unit 500 waits for the completion of paper feed in step S114. Here, the completion of paper feeding means that the pulse signal sent from the drive control circuit 510 shown in FIG. 3 to the transport motor 570 of the printer driving device 520 reaches the predetermined number of pulses calculated as described above.
Therefore, when the pulse signal to the transport motor 570 reaches the predetermined number of pulses as described above, the system control unit 500 determines that the paper feeding is completed, and cuts the roll paper in step S115. At this time, the system control unit 500 sends a paper cut signal to the cutter motor 540 of the printer driving device 520 through the drive control circuit 510. Accordingly, the cutting device 40 shown in FIG. 1 rotates the cutter by the cutter motor 540 to cut the roll paper.

Then, the system control unit 500 ends the process shown in FIG. Actually, the process of a general process for forming an image on the cut transfer paper continues thereafter. However, since this has been described with reference to FIGS. 1 and 2, the description thereof is omitted here.
According to this embodiment, whether or not there is a valid image at the rear end of the image data for one document is determined based on the pixel count information described above. Feed and cut longer than the length by the correction value. Therefore, it is possible to prevent image missing from occurring at the rear end of the recording medium piece.

In this embodiment, the image information storage unit 300 that is a storage unit includes a pixel count unit that counts the number of pixels in the main scanning direction of image information for performing image formation at least in a predetermined region at the rear end of the image, The count value by the pixel counting means is stored.
When the count value stored in the image information storage unit 300 is greater than or equal to a preset value, the system control unit 500 serving as a cutting position changing unit determines a position for cutting a long recording medium (roll paper). The recording medium piece is changed to be long.
As a result, an effective image at the rear end of the image of one page can be accurately detected, the cutting position of the long recording medium can be corrected, and image loss can be reliably prevented.

Further, the image information storage unit 300 has pixel counting means for counting the number of pixels in the main scanning direction of the image information for each line of at least a predetermined number of lines at the rear end of the image. It is also possible to store a count value for each line.
In that case, the system control unit 500 serving as the cutting position changing unit is long when the count value for each line stored in the image information storage unit 300 is equal to or greater than the preset number of lines. The position for cutting the recording medium is changed as described above.
In this way, it is possible to more accurately detect an effective image at the rear end of the image of one page, correct the cutting position of the long recording medium, and prevent image loss more reliably.
The predetermined number of lines, the value set in advance for the count value of the number of pixels in order to determine the effective pixel, and the number of lines set in advance can be arbitrarily changed.

The process flow of the embodiment in which the process of adjusting the correction value of the paper length according to the environmental change is added to the process of FIG. 5 will be described with reference to the flowchart of FIG.
In the flowchart of FIG. 6, steps S201 to S203 (shown by hatching) are only inserted between steps S110 and S111 in FIG. Therefore, steps having the same contents as those in FIG. 5 are denoted by common step symbols, and description thereof is omitted.

  When the system control unit 500 determines that “there is an effective image” in step S110 of FIG. 6, that is, when the count value of the pixel count information is greater than or equal to a predetermined value set in advance, the temperature / humidity information in the apparatus is acquired in step S201. To do. That is, the temperature and humidity information measured by the temperature / humidity sensor 80 (temperature / humidity detection means) provided in the main body 200 shown in FIGS. 1 and 2 is acquired.

In step S202, the temperature / humidity information is compared with the previously acquired temperature / humidity information to determine whether there is an environmental change. As a result, if it is determined that the environment has changed, the correction value for the paper length is adjusted in step S203. In that case, the correction value to be added to the predetermined sheet length is adjusted in the subsequent step S111.
For example, in a high-temperature and high-humidity environment, the transfer force increases because the diameter of the transfer roller expands. As a result, the speed at which the cut recording medium piece is conveyed increases, and the rear end of the recording medium piece tends to pass through the transfer position before the rear end of the image. Therefore, it is necessary to adjust the correction value. In the adjustment, a correction coefficient is determined by a predetermined environment classification of temperature and humidity, and is added to the correction value.

If it is determined in step S202 that there is no environmental change, the process directly proceeds to step S111, and a predetermined correction value is added to the calculated predetermined sheet length.
The subsequent processing is the same as the processing in steps S112 to S115 described with reference to FIG.

Next, an embodiment having an image input / output parallel operation mode in which writing is performed during image accumulation will be described. The image input / output parallel operation mode is selected by the operation unit 400 described above.
7 and 8 are flowcharts showing the flow of processing by the system control unit 500 in the embodiment. In these figures, steps having the same contents as those in FIG. 5 are denoted by common step symbols.

FIG. 7 is a flowchart showing a flow of processing relating to image data accumulation, and steps S350 to S354 (shown by hatching) are steps added to steps S101 to S108 in FIG.
FIG. 8 is a flowchart showing a flow of processing relating to writing, and steps S370 to S377 (shown by hatching) are steps added to steps S109 to S115 in FIG.
In the following description, parts different from those in FIG. 5 will be mainly described.

The system control unit 500 starts processing related to image data storage by “accumulation start” shown in FIG. 7, and executes the processing of steps S102 to S105 when it is determined that there is a print request in step S101 as in FIG. .
In step S105, counting of the number of pixels of the image data is started. In step S350, it is determined whether or not the image input / output parallel operation mode is selected from the operation mode information. As a result, if it is the image input / output parallel operation mode, the process proceeds to step S351 to notify the paper feed start request, and then waits for completion of image data accumulation in step S106. If it is not in the image input / output parallel operation mode, the paper feed start request is not notified, and the completion of image data accumulation is waited in step S106.

After the image data accumulation is completed, the system control unit 500 reads the pixel count information in step S108 and stores the pixel count information read as the printing operation information in step S352.
Next, in step S353, it is determined whether or not a paper feed start request has been notified. If it has been notified, the process is terminated. If not, the process is terminated and a paper feed start request is notified in step S354. End the process.

The system control unit 500 starts processing related to image writing by “writing start” shown in FIG. 8, determines whether there is a paper feed start request in step S370, and if there is no paper feed start request, feeds paper in step S371. It enters a start request waiting state and waits for a paper feed start request.
If there is a paper feed start request, printing operation information necessary for the printing operation is acquired in step S109, and in step S372, it is determined whether or not it is an image input / output parallel operation mode based on the printing operation mode information.

As a result, in the image input / output parallel operation mode, steps S110 and S111 are skipped, and the process proceeds to step S112 to start paper feeding. If it is not in the image input / output parallel operation mode, it is determined whether there is a valid image in step S110, a correction value is added to a predetermined sheet length in step S111, and paper feeding is started in step S112.
Then, the system control unit 500 starts writing in step S113, and then determines whether or not the image input / output parallel operation mode is set in step S373.
As a result, if it is not the image input / output parallel operation mode, the completion of paper feed is waited in step S114. If it is the image input / output parallel operation mode, the process proceeds to step S374 and waits for the end of storage of pixel count information (storage of pixel count information after completion of image data storage).

When the storage of the pixel count information is completed, the writing operation is reset according to the image size determined in step S375, and it is determined whether there is a valid image in step S376. As a result, if there is an effective image, the number of paper feed pulses is added to correct the paper length in step S377, and the roll paper before cutting is fed longer than a predetermined length.
In step S114, the process waits for the completion of paper feed. When the paper feed is completed, the roll paper is cut in step S115, and the process ends. If it is determined in step S376 that there is no valid image, the paper length is not corrected and the completion of paper feeding is awaited in step S114.

Also in this embodiment, it is determined whether or not there is an effective image at the rear end of the image data in the sub-scanning direction. If there is an effective image, the roll paper is fed longer than a predetermined length. Since the cutting is performed, it is possible to prevent image missing at the rear end of the recording medium.
In addition, since the image forming apparatus according to this embodiment has an image input / output parallel operation mode, a paper feed start request is notified before image data accumulation is completed, and processing for image writing is performed. It is possible to start and increase the productivity of image formation.

According to the control method of the image forming apparatus according to the present invention, the long recording medium wound in the roll shape as described above is fed out and fed, and the recording medium is cut into a required length, and the cutting is performed. This is a control method of an image forming apparatus that forms an image for each page on a recording medium piece.
Of the image information for forming an image for each page, information on pixels for which image formation is to be performed is stored at least in a predetermined region at the rear end of the image.
When the stored pixel information is greater than or equal to a preset value, the position at which the long recording medium is cut is changed so that the recording medium piece becomes longer.
The embodiment is the same as that described for each embodiment of the image forming apparatus described above.

Furthermore, the program according to the present invention includes a computer that controls an image forming apparatus that forms an image for each page on a recording medium piece obtained by cutting a long recording medium into a predetermined length as described above, and the storage unit. It is a program for functioning as the cutting position changing means.
The embodiment is a program for causing a computer that performs the function of the system control unit 500 shown in FIG. 3 to execute the processes shown in the flowcharts of FIGS.
The program may be stored in advance in a computer-readable memory provided in the image forming apparatus, or may be read from various recording media such as a computer-readable portable CD-ROM. . Or you may enable it to download via networks, such as the internet.

As mentioned above, although embodiment of this invention was described, the specific structure of each part of the embodiment, the content of a process, etc. are not restricted to what was described there.
Further, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention is not limited in any way except for having the technical features described in the claims.

For example, as an embodiment of the image forming apparatus according to the present invention, the example in which the LED print head (LPH) is used for the writing unit has been described. However, the present invention is not limited to this, and a writing apparatus using a laser beam method or the like may be used. . Alternatively, the present invention can be applied not only to an electrophotographic image forming apparatus but also to an inkjet image forming apparatus. Further, the present invention can be applied not only to a monochrome image but also to various image forming apparatuses that form a color image.
Furthermore, the configuration example, the operation example, the modification example, and the like of the above-described embodiment may be appropriately changed or added, or a part thereof may be deleted, and may be implemented in any combination as long as they do not contradict each other.

10: Document table 11: Document feeding roller 12: Contact sensor 13: White roller
14, 15: Document discharge roller 16: Switching claw 17A: Straight discharge path
17B: Reverse paper discharge path 18: Document discharge tray 19: Sensor group 20: Roll paper supply unit 21A, 21B, 21C: Roll paper (recording medium)
22: Support shaft 23, 24, 25: Feeding roller 26, 27: Paper feeding and conveying roller
30: Image forming process unit 31: Photoconductor 32: Charger 33: Writing units 33A, 33B, 33C: LED print head (LPH) 34: Developing device
35: Transfer roller 36: P sensor 37: Cleaning device 38: Static eliminator
40: Cutting device 41: Tip detection sensor 60: Fixing device 61: Fixing roller
62: Pressure roller 71: Conveying roller 72: Positioning roller
73, 74: paper discharge roller 75: switching claw 76A: linear paper discharge path
76B: Reverse paper discharge path 80: Temperature / humidity sensor (temperature / humidity detection means)
100: Document reading unit 102: Image amplification circuit 103: A / D conversion circuit
104: Shading correction circuit 105: Image processing circuit
106: Synchronization control circuit 107: Reading control circuit 108: Scanner driving device 200: Main body (image forming unit) 201: Housing 202: Caster
203: Paper discharge tray
300: Image information storage unit 310: Image memory unit 330: LED writing control circuit
331: Image memory control unit 332: Density conversion processing unit
333: Image data thinning processing unit 334: Data division control unit 335: Lighting time control unit 336: Lighting control unit 337: Storage unit 400: Operation unit 401: Operation control circuit 402: Operation panel
500: System control unit 510: Drive control circuit 520: Printer drive device 540: Cutter motor 570: Conveyance motor

JP 2004-226560 A

Claims (7)

An image forming apparatus that feeds and feeds a long recording medium wound in a roll shape, cuts the recording medium into a predetermined length, and forms an image for each page on the cut recording medium piece Because
Storage means for storing pixel information for image formation in at least a predetermined region at the rear end of the image among image information for forming an image for each page;
Cutting position changing means for changing the position of cutting the long recording medium so that the length of the recording medium piece is longer when the pixel information stored in the storage means is greater than or equal to a preset value;
An image forming apparatus comprising: The image forming apparatus according to claim 1.
Temperature and humidity detection means for detecting the temperature and humidity in the machine;
Means for adjusting a correction value for changing the position at which the cutting position changing means cuts the long recording medium with reference to temperature / humidity information detected by the temperature / humidity detecting means. Image forming apparatus.   Before the image information for forming the image for each page is stored in the storage unit, the information on the pixels on which image formation is performed at least in a predetermined region at the rear end of the image is completed. 3. The image forming apparatus according to claim 1, wherein feeding of the recording medium is started. The storage means has pixel counting means for counting the number of pixels in the main scanning direction of image information for image formation at least in a predetermined area at the rear end of the image, and stores the count value by the pixel counting means. Means,
The cutting position changing unit changes the position at which the long recording medium is cut so that the recording medium piece becomes longer when the count value stored in the storage unit is equal to or larger than a preset value. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The storage means has pixel counting means for counting the number of pixels in the main scanning direction of the image information for each line of at least the predetermined number of lines at the rear end of the image, and for each line by the pixel counting means. Means for storing the count value of
The cutting position changing means is a position for cutting the long recording medium when the count value for each line stored in the storage means is equal to or more than a preset number of lines. The image forming apparatus according to claim 4, wherein the recording medium piece is changed to be longer. An image forming apparatus that feeds and feeds a long recording medium wound in a roll shape, cuts the recording medium into a predetermined length, and forms an image for each page on the cut recording medium piece Control method,
Of the image information for forming an image for each page, information on pixels for which image formation is performed at least in a predetermined region at the rear end of the image is stored,
When the stored pixel information is greater than or equal to a preset value, the position for cutting the long recording medium is changed so that the recording medium piece becomes long. . An image forming apparatus that feeds and feeds a long recording medium wound in a roll shape, cuts the recording medium into a predetermined length, and forms an image for each page on the cut recording medium piece Control the computer,
Storage means for storing pixel information for image formation in at least a predetermined region at the rear end of the image among image information for forming an image for each page;
When the pixel information stored in the storage means is greater than or equal to a preset value, the cutting position changing means changes the position at which the long recording medium is cut so that the length of the recording medium piece becomes longer. A program to make it work.

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