JP2015055846A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that forms images on a continuous sheet and performs image density control even during image formation processing.SOLUTION: An image forming apparatus includes: image forming means for transferring a toner image on an image holding body to a continuous sheet to form an image; and control means for controlling, before image formation on the continuous sheet, the image forming means so as to form a density adjustment toner image on the image holding body while the image holding body and the continuous sheet are separated from each other and performing a first density control based on the density of the density adjustment toner image, and performing, during the image formation on the continuous sheet, a second density control different from the first density control while the image holding body and the continuous sheet are in contact with each other.

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses a developing unit that develops a latent image formed on an image carrier, a detection unit that detects the amount of toner in the developing unit, a toner replenishing unit that replenishes toner to the developing unit, Based on the detection result of the detection unit, a toner replenishment time for replenishing toner with respect to a predetermined basic time is determined, and the toner replenishment unit is controlled to repeat toner replenishment based on the toner replenishment time every basic time And an image forming apparatus including the control unit.

  In Patent Document 2, an electrostatic latent image formed on a predetermined image carrier is developed with toner in the developer using a developing device that holds a two-component developer having toner and carrier inside. In the image forming apparatus for forming an image composed of the fixed toner image on the recording medium by finally transferring and fixing the toner image formed on the image carrier by the development onto a predetermined recording medium. The density of a reference toner image formed by developing a reference electrostatic latent image formed on the image carrier with toner is measured on the image carrier or a transfer body that has received the transfer of the reference toner image. Based on the toner image density measuring means and the image signal, an image density and a toner consumption representing an area ratio of a portion to which toner is attached by development on the electrostatic latent image formed based on the image signal are predicted. Toner consumption forecast And the toner consumption predicted by the toner consumption prediction means, or based on the toner consumption predicted by the toner consumption prediction means, or the toner image density measurement means. An image forming apparatus comprising: a toner supply control unit that controls toner supply to the developing device based on both the density of the reference toner image measured by the above.

JP 2004-101965 A JP 2002-196551 A

  An object of the present invention is to provide an image forming apparatus that forms an image on continuous paper, and in which image density control is performed even during image forming processing.

  According to the first aspect of the present invention, the image forming unit that forms an image by transferring the toner image on the image holding member onto the continuous paper, and the image holding member and the continuous paper are separated before the image is formed on the continuous paper. The image forming unit is controlled to form a density adjusted toner image on the image holding member in the state, and the first density control is performed based on the density of the density adjusted toner image, and during image formation on continuous paper, The image forming apparatus includes a control unit that performs second density control different from the first density control when the image carrier and the continuous paper are in contact with each other.

  According to a second aspect of the present invention, the second density control predicts a toner consumption amount based on the image information, and controls a toner supply amount to the developing device based on the predicted toner consumption amount. And at least one of density control for detecting the ratio of toner to carrier in the developer in the developer and controlling the amount of toner supplied to the developer based on the obtained detection result. An image forming apparatus.

  A third aspect of the present invention is the image forming apparatus according to the second aspect, wherein the predicted toner consumption is corrected according to an environmental condition including at least one of temperature and humidity.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the predicted toner consumption is corrected according to a paper width of continuous paper.

  According to a fifth aspect of the present invention, the controller controls the first density control before the image is formed on the continuous paper and before the continuous paper is supplied to the transfer position with no continuous paper at the transfer position. The image forming apparatus according to claim 1, wherein the image forming apparatus is performed.

  According to the first aspect of the present invention, the image forming apparatus performs image formation on continuous paper, and the image density control is also performed during the image forming process.

  According to the second aspect of the present invention, image density control is performed without forming a density-adjusted toner image.

  According to the third aspect of the present invention, fluctuations in toner consumption due to environmental conditions including at least one of temperature and humidity are corrected.

  According to the fourth aspect of the present invention, the fluctuation of the toner consumption due to the paper width of the continuous paper is corrected.

  According to the fifth aspect of the present invention, image density control is performed even when there is no continuous paper at the transfer position.

1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which shows an example of a structure of label paper. It is the schematic which shows an example of a structure of an image forming apparatus. It is the schematic which shows a mode that a secondary transfer roll moves. 2 is a block diagram illustrating an example of a configuration of a control system of the image forming apparatus according to the embodiment of the present invention. FIG. 10 is a flowchart illustrating an example of a procedure of “image formation processing”. It is a flowchart which shows the procedure of "1st density control." It is a flowchart which shows the procedure of "2nd density control." 10 is a flowchart illustrating another example of the procedure of “image formation processing”.

  Embodiments of the present invention will be described below with reference to the drawings.

<Overall configuration of image forming apparatus>
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 10 according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 10 includes a paper feeding device 12 that feeds continuous paper P that is a recording medium, and an image forming unit 14 that forms an image on the continuous paper P fed from the paper feeding device 12. And a storage device 16 that stores the continuous paper P on which an image is formed by the image forming unit 14, and a control device 18 that controls each of the paper feeding device 12, the image forming unit 14, and the storage device 16. .

  The paper feeding device 12 supplies a continuous long continuous paper P as a recording medium, and the storage device 16 stores the continuous paper P on which an image is formed by the image forming unit 14.

  As the continuous paper P, for example, a transfer member made of high-quality paper, glassine paper, or synthetic resin such as PP (polypropylene) is used. As shown in FIG. On the release paper 51 to be discarded, a so-called label paper is used in which a surface base 53 provided in the uppermost layer is adhered via an adhesive layer 52 made of an adhesive material such as glue as an intermediate layer. A pattern and characters are printed on the surface base material 53 and used. The label paper 5 is arranged as a roll paper wound in a roll shape so that the surface base 53 side is positioned on the surface (outer peripheral surface) which is an image forming surface, depending on the application.

  The paper feeding device 12 is provided with a paper feeding roll 20 made of continuous paper P wound up in a roll shape, and the paper feeding roll 20 is driven to rotate by a driving means (not shown) so that the continuous paper P forms an image. Supplied to the unit 14.

  In addition, the storage device 16 is provided with a storage roll 22 in which the continuous paper P on which an image has been formed is wound up in a roll shape.

  Based on the image information, the image forming unit 14 applies an image using four color toners of yellow (Y), magenta (M), cyan (C), and black (K) to the continuous paper P. Form. The image forming unit 14 holds an image forming device 24 that forms a toner image developed with toner constituting the developer, and a toner image formed by the image forming device 24, respectively. The intermediate transfer device 26 transports the toner image to the secondary transfer position for secondary transfer, the secondary transfer device 46 for secondary transfer of the toner image onto the continuous paper P at the secondary transfer position, and the secondary transfer device 46 for secondary transfer. A fixing device 28 for fixing the toner image on the continuous paper P is provided.

  The image forming device 24 includes four image forming devices 24Y, 24M, 24C, and 24K that respectively form toner images of Y, M, C, and K colors.

  FIG. 3 is a schematic diagram showing an example of the configuration of the image forming apparatus. As shown in FIG. 3, each image forming device 24 includes a photosensitive drum 30 as an example of a rotating image carrier. Around each photosensitive drum 30, a charging device 32, an exposure device 34, a developing device 36, a primary transfer device 38, a cleaning device 40, and the like, which will be described later, are provided.

  The photosensitive drum 30 has an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar base material that has been grounded. Further, the photosensitive drum 30 is supported so as to be rotated by transmission of power by a driving device (not shown).

  The charging device 32 is configured to include a contact-type charging roll 32 </ b> A that is disposed in contact with the photosensitive drum 30, and charges the peripheral surface of the photosensitive drum 30 where image formation is possible. A charging voltage is supplied to the charging device 32. As the charging voltage, when the developing device 36 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 36 is supplied.

  The exposure device 34 irradiates the charged peripheral surface of the photosensitive drum 30 with light based on the image information to form an electrostatic latent image on the peripheral surface of the photosensitive drum 30.

  The developing device 36 develops the electrostatic latent image formed on the peripheral surface of the photosensitive drum 30 by the exposure device 34 with toner of a corresponding color developer to generate a toner image. Although not shown, the developing device 36 is agitated and conveyed such as a developing roll that conveys the developer to a developing area facing the photosensitive drum 30 and a screw auger that conveys the developer so as to be supplied to the developing roll while stirring the developer. A member and a layer thickness regulating member for regulating the amount of developer held on the developing roll are arranged.

  A developing bias voltage is applied to the developing device 36 between the developing roll and the photosensitive drum 30. Further, the developing roll and the agitating / conveying member rotate in a predetermined direction by receiving power from a rotation driving device (not shown). As the developer, for example, a two-component developer containing a non-magnetic toner and a magnetic carrier can be used. Further, the developing device 36 is provided with a toner concentration sensor 60 for measuring toner concentration (TC: Toner Concentration) in the developing device.

  The developing device 36 is supplied with toner from a toner cartridge 42 containing a developer containing toner of each color. The toner stored in the toner cartridge 42 is supplied to the developing device 36 by the toner replenishing motor 62. Accordingly, the toner supply amount is controlled by controlling the toner supply motor 62.

  The primary transfer device 38 is a contact type transfer device provided with a primary transfer roll 38A that rotates in contact with the peripheral surface of the photosensitive drum 30 and is supplied with a primary transfer voltage. By supplying the primary transfer voltage to the primary transfer roll 38 </ b> A, the toner images of the respective colors formed on the photosensitive drum 30 are transferred to the intermediate transfer device 26. As the primary transfer voltage, a DC voltage having a polarity opposite to the charging polarity of the toner is applied.

  Further, the cleaning device 40 removes and removes adherents such as toner remaining on the image holding surface of the photosensitive drum 30 after the primary transfer. In the present embodiment, the cleaning device 40 is provided with a blade 40A that comes into contact with the photosensitive drum 30. The blade 40A removes deposits attached to the peripheral surface of the photosensitive drum 30. Yes.

  As shown in FIG. 1, the intermediate transfer device 26 is disposed at a position below each image forming device (24Y, 24M, 24C, 24K) 24. In the present embodiment, the intermediate transfer device 26 includes an intermediate transfer belt 44 that rotates in the direction indicated by arrow A while passing through a primary transfer position between the photosensitive drum 30 and the primary transfer device 38, and an intermediate transfer belt. A plurality of support rolls 26 </ b> A to 26 </ b> C that rotatably support 44 and a secondary transfer device 46 that secondarily transfers the toner image on the intermediate transfer belt 44 onto the continuous paper P are mainly provided. Although not shown in the figure, the intermediate transfer device 26 is cleaned by removing toner and paper dust adhering to the outer peripheral surface of the intermediate transfer belt 44 after passing through the secondary transfer device 46. A belt cleaning device is provided.

  As the intermediate transfer belt 44, for example, an endless belt made of a material in which a resistance adjusting agent such as carbon black is dispersed in a synthetic resin such as polyimide resin or polyamide resin is used.

  As shown in FIG. 1, the secondary transfer device 46 has a peripheral transfer belt 44 at a secondary transfer position that is an outer peripheral surface portion of the intermediate transfer belt 44 supported by the belt support roll 26 </ b> C in the intermediate transfer device 26. The contact type transfer device includes a secondary transfer roll 46A that rotates in contact with the surface and is supplied with a secondary transfer voltage. As will be described later, the secondary transfer device 46 includes a moving mechanism that moves the secondary transfer roll 46A.

  Further, a DC voltage having a polarity opposite to or the same as the charging polarity of the toner is applied as a secondary transfer voltage to the secondary transfer roll 46A or the support roll 26C of the intermediate transfer device 26. A density sensor 48 for detecting the density of the toner image transferred to the intermediate transfer belt 44 is provided on the intermediate transfer belt 44, and the toner supply amount is based on the density detection result of the density sensor 48. Is controlled.

The fixing device 28 is in contact with a rotating rotator 28A in the form of a roll or belt heated by heating means so that the surface temperature is maintained at a predetermined temperature, and the rotating rotator 28A for heating at a predetermined pressure. Thus, a pressurizing rotating body 28B or the like in the form of a roll or belt that rotates is arranged. In the fixing device 28, the toner image transferred onto the continuous paper P by the secondary transfer device 46 is heated and pressed to perform a fixing process.

<Basic operation of image forming apparatus>
Subsequently, a basic image forming operation by the image forming apparatus 10 will be described.
Upon receiving a request for an image forming operation (printing), the image forming apparatus 10 includes four image forming devices (24Y, 24M, 24C, 24K) 24, an intermediate transfer device 26, a secondary transfer device 46, a fixing device 28, and the like. Starts.

  In each image forming device 24, first, each photosensitive drum 30 is rotated, and the surface of each photosensitive drum 30 is charged to a predetermined polarity and potential by each charging device 32. Subsequently, the exposure device 34 irradiates the charged surface of the photosensitive drum 30 with light based on image information, whereby an electrostatic latent image of each color component is formed on the surface of the photosensitive drum 30. .

  Subsequently, toner of corresponding colors (Y, M, C, K) charged to a predetermined polarity is respectively applied to the electrostatic latent image of each color component formed on the photosensitive drum 30 by each developing device 36. Supplied and electrostatically attached, the electrostatic latent image is developed. As a result, the electrostatic latent image of each color component formed on the photosensitive drum 30 is visualized as a toner image of four colors (Y, M, C, K) developed with the corresponding color toner. The

  Subsequently, when each color toner image formed on the photosensitive drum 30 of each image forming device 24 is conveyed to the primary transfer position, each color toner image is transferred to the intermediate transfer belt 44 by the primary transfer device 38. Primary transfer is performed in the state of being superimposed in order.

  Further, in each image forming device 24 in which the primary transfer has been completed, the cleaning device 40 removes deposits such as toner remaining on the surface of the photoconductive drum 30 to clean the surface of the photoconductive drum 30. As a result, each image forming device 24 becomes ready for the next image forming operation.

  Subsequently, in the intermediate transfer device 26, the toner image primarily transferred by the rotation of the intermediate transfer belt 44 is held and conveyed to the secondary transfer position. On the other hand, in the paper feeder 12, the continuous paper P is supplied from the paper feed roll 20 to the secondary transfer position along a predetermined conveyance path prior to the image forming operation.

  At the secondary transfer position, the toner image on the intermediate transfer belt 44 is secondarily transferred onto the continuous paper P all at once by the secondary transfer device 46. In addition, in the intermediate transfer device 26 that has finished the secondary transfer, a toner such as toner remaining on the surface of the intermediate transfer belt 44 after the secondary transfer is removed by a belt cleaning device (not shown).

  Subsequently, the continuous paper P onto which the toner image has been secondarily transferred is conveyed to the fixing device 28, and the fixing device 28 performs a fixing process to fix the toner image on the continuous paper P. Finally, the continuous paper P after the fixing is finished is discharged from the image forming unit 14 and taken up on the storage roll 22 of the storage device 16.

  With the above operation, the continuous paper P on which a full color image composed of a combination of four color toner images is formed is output.

Here, the moving mechanism of the secondary transfer device 46 will be described.
FIG. 4 is a schematic view showing how the secondary transfer roll moves. As shown in FIG. 4, the secondary transfer device 46 includes a moving mechanism having a motor 66. When “first density control” described later is executed, the moving mechanism motor 66 is driven to move the secondary transfer roll 46A downward (in the direction of arrow B). The secondary transfer roll 46A is moved from the reference position indicated by the dotted line to the position indicated by the solid line.

  At the reference position indicated by the dotted line, the secondary transfer roll 46A presses the continuous paper P, and the intermediate transfer belt 44 and the continuous paper P are in contact with each other. At the position indicated by the solid line, the secondary transfer roll 46A moves downward, and the intermediate transfer belt 44 and the continuous paper P are separated from each other and do not come into contact with each other. In a state where the intermediate transfer belt 44 and the continuous paper P are not in contact, even if a toner image is formed on the intermediate transfer belt 44, the toner image is not transferred onto the continuous paper P.

  In the present embodiment, the following description is based on a mode in which the secondary transfer roll 46A moves downward. However, the secondary transfer roll 46A may have a moving mechanism that moves the support roll 26C facing the secondary transfer roll 46A. Good.

<Control system configuration>
Next, the configuration of the control system of the image forming apparatus 10 according to the present embodiment will be described. FIG. 5 is a block diagram showing an example of the configuration of the control system of the image forming apparatus according to the embodiment of the present invention. FIG. 5 shows the configuration of a control system for controlling the image forming unit 14.

  The control device 18 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage device, and the like, and is configured as a computer that controls the entire device and performs various calculations. Yes. The CPU reads a program stored in a storage device such as a ROM, and executes the program using the RAM as a work area.

  Various drives may be connected to the control device 18. Each type of drive is a device that reads data from a computer-readable portable recording medium such as a flexible disk, a magneto-optical disk, or a CD-ROM, and writes data to the recording medium. When various drives are provided, the program may be recorded on a portable recording medium and read and executed by the corresponding drive.

  As described above, the image forming unit 14 is controlled by the control device 18. That is, each component of the image forming device 24 is connected to the control device 18. More specifically, a charging device 32, an exposure device 34, a developing device 36, a primary transfer device 38, and a cleaning device 40 are connected, and each operation is controlled by the control device 18, so that an image forming operation is performed. Done.

  The toner density sensor 60 for detecting the toner density in the developing device 36, the toner replenishing motor 62, the density sensor 48 for detecting the density of the toner image on the intermediate transfer belt 44, and the moving mechanism motor 66 for the secondary transfer roll 46A. Is also connected to the control device 18. The detection results of the toner density sensor 60 and the density sensor 48 are input to the control device 18. The toner supply motor 62 and the moving mechanism motor 66 are driven and controlled by the control device 18.

  Further, a pixel counter 64 is connected to the control device 18. The pixel counter 64 counts (counts) the number of pixels or the image density (area coverage) based on the image information. The count result of the pixel counter 64 is input to the control device 18. The pixel counter 64 is described as counting the number of pixels and the image density from the image information, but is not limited to this. The lighting time of the exposure device 34 may be counted.

  In addition to controlling the image forming operation, the control device 18 controls the toner supply motor 62 based on the detection result of the density sensor 48, the detection result of the toner density sensor 60, the count result of the pixel counter 64, etc. It is configured to execute “image density control” for controlling the supply amount and controlling the output toner density.

  As a method of “image density control”, a density adjustment pattern (toner image) called a patch or the like is formed on the intermediate transfer belt, the density of the density adjustment pattern is detected by the density sensor 48, and based on the detection result. There is a method of controlling the density by controlling the toner supply motor 62. According to this method, it is possible to detect a transfer state close to the actual image formation result by detecting the density adjustment pattern on the intermediate transfer belt. This method is an example of feedback control and is referred to as ADC control (Auto Density Control).

  As another method of “image density control”, the number of pixels, the image density, and the like are counted based on the image information, the toner consumption amount is predicted based on the counting result, and the toner supply motor 62 is controlled based on the prediction result. There is a way to control. This method is an example of feedforward control (predictive control), and is called ICDC control (Image Count Dispense Control).

  As another method, there is a method in which the toner density sensor 60 detects the toner density in the developing device 36 and controls the toner replenishment motor 62 based on the detection result of the toner density sensor 60. The toner density in the developing device 36 is a ratio of toner to carrier (developer permeability) in the developer. Control is performed so that the toner density in the developing device 36 becomes a predetermined value. This method is an example of feedforward control (predictive control) in that no density adjustment pattern is formed, and is called ATC control (Auto Toner Concentration Control).

  In the present embodiment, the density control (ADC control) based on the detection result of the density sensor 48 is referred to as “first density control”. Further, density control based on prediction such as ICDC control and ATC control is referred to as “second density control”. The “second density control” is not limited to the formation of density adjustment pattern (toner image) and density detection, and any density control based on prediction may be performed, and is limited to ICDC control and ATC control. Not a translation.

  In an electrophotographic image forming apparatus, “image density control” is executed at a predetermined time. The image forming process is executed as a series of processes for forming a group of images according to an image forming instruction. Conventionally, in an image forming apparatus that forms an image on a cut sheet, when the “image density control” time comes during the image forming process, ADC control is performed at a timing at which image formation between sheets is not performed.

  However, in the case of an image forming apparatus that forms an image on continuous paper, there is no timing for not performing image formation between sheets. If ADC control is performed during the image forming process, the density adjustment pattern is transferred onto the continuous paper. The portion where the image of the density adjustment pattern is recorded is cut out from the continuous paper after the image forming process is completed. Note that if ADC control is performed while avoiding transfer of the density adjustment pattern, the image forming process is interrupted.

  Therefore, in the present embodiment, before the start of the image forming process which is a series of processes, “first density control” which is density control (ADC control) based on the detection result of the density sensor 48 is performed, and the image forming process is performed. After the start, “second density control” which is density control based on prediction is performed. When performing the “first density control”, the secondary transfer roll 46A is moved downward so that the intermediate transfer belt 44 and the continuous paper P are not in contact with each other. Accordingly, even in the case of an image forming apparatus that forms an image on continuous paper, “image density control” is performed during the image forming process. As a result, the image quality of the image formed on the continuous paper by the image forming apparatus is stabilized.

<Image formation processing>
Next, the flow of image forming processing will be described. FIG. 6 is a flowchart showing an example of the flow of processing performed by the control device 18 of the image forming apparatus 10 according to the present embodiment. A program for performing the image forming process is executed by the CPU of the control device 18.

  When an image formation instruction is issued, it is determined in step 100 whether or not the continuous paper P is set. This determination is made based on, for example, a detection result of a paper detection sensor or the like. If the determination is negative, the process proceeds to step 102. If the determination is affirmative, the process proceeds to step 104.

  In step 102, a predetermined continuous paper setting process for setting the continuous paper P is performed, and the process proceeds to step 104. In the continuous paper setting process, for example, the paper supply device 12, the image forming unit 14, and the storage device 16 are controlled, and the continuous paper P is pulled out from the paper supply roll 20 of the paper supply device 12 and passed through the image forming device 10. Then, the continuous paper P is automatically conveyed so as to be accommodated in the accommodation device 16.

  In step 104, “first density control” is performed. Next, in step 106, an image forming process is started. That is, “first density control” based on the detection result of the density sensor 48 is performed before the image forming process is started.

  Next, in step 108, it is determined whether or not the “image density control” time has come. If it is time for "image density control", the process proceeds to step 110. If it is not time for "image density control", this determination is repeated.

  In step 110, it is determined whether a series of processes corresponding to the image formation instruction has been completed. If the series of processes has not been completed, that is, if the image forming process is in progress, the process proceeds to step 1112. In step 112, “second density control” is performed. On the other hand, if a series of processing is completed in step 110, the process proceeds to step 114. Here, the end of the series of processes is not limited to all jobs corresponding to the image formation instruction, but may be a case where image formation corresponding to a certain amount of jobs is performed.

  In step 114, it is determined whether or not the image forming process is finished. If the image forming process has been completed, the routine ends. On the other hand, if the image forming process has not been completed, the process returns to step 108 and the procedure from step 108 to step 114 is repeated.

Here, the flow of “first density control” will be described with reference to FIG.
In “first density control”, first, in step 200, the moving mechanism motor 66 is controlled so that the contact state between the intermediate transfer belt 44 and the continuous paper P is released, and the secondary transfer roll 46A is moved downward. Moving. When the intermediate transfer belt 44 and the continuous paper P are separated from each other, the density adjustment pattern formed on the intermediate transfer belt 44 is not transferred to the continuous paper P.

  Next, in step 202, the image forming unit 14 is controlled so as to form a predetermined density adjustment pattern on the intermediate transfer belt 44, and the process proceeds to step 204. In step 204, the density of the density adjustment pattern is detected by the density sensor 48, and the process proceeds to step 206. In step 206, image density control is performed by controlling the toner replenishment motor 62 based on the detection result of the density sensor 48.

  Finally, in step 208, the moving mechanism motor 66 is controlled to return the intermediate transfer belt 44 and the continuous paper P to the contact state, and the secondary transfer roll 46A moves upward. This completes the “first density control” routine.

  Next, the flow of “second density control” will be described with reference to FIG. Here, an example of ICDC control will be described, but ATC control or other prediction control may be used. Further, in addition to the ICDC control, control can be performed by combining ATC control or other predictive control, factors such as environmental conditions described later, paper characteristics such as paper width of continuous paper, or the like in combination.

  In “second density control”, first, in step 300, image information is acquired, and the pixel counter 64 counts the number of pixels. Next, in step 302, the toner consumption amount is predicted based on the counting result. Finally, in step 304, image density control is performed by controlling the toner replenishment motor 62 based on the predicted toner consumption. This completes the “second density control” routine.

  Further, the toner consumption varies depending on other factors such as environmental conditions such as temperature and humidity, and the paper width of continuous paper. Therefore, the predicted value of toner consumption calculated from the number of pixels may be corrected in consideration of these other factors. For example, at least one of the environmental conditions and the continuous paper width, the counting result such as the number of pixels, and the relationship between the correction amount of the toner consumption are acquired in advance, and the predicted value of the toner consumption is corrected based on the relationship. May be. These relationships may be stored as a table, a graph, or the like.

  The environmental condition at the time of correction may be acquired by an environmental sensor such as a temperature sensor or a humidity sensor, for example. Further, the paper width at the time of correction may be obtained based on, for example, the detection result of the paper width detection sensor and the paper width designation by the user.

  In the procedure shown in FIG. 6, the example of performing the “first density control” after the continuous paper setting process has been described. However, during the continuous paper setting process, that is, during the automatic conveyance of the continuous paper P, the transfer position is set. The “first density control” may be performed during a period when there is no continuous paper P. FIG. 9 is a flowchart showing the procedure of the “image forming process” in this case. The same steps as those in the image forming process shown in FIG.

  In this case, the density adjustment pattern formed on the intermediate transfer belt 44 is not transferred to the continuous paper P, but the contact state between the intermediate transfer belt 44 and the secondary transfer roll 46A from the viewpoint of preventing the transfer roll 46A from being soiled. Is released once. However, the “first density control” can be performed without releasing the contact state between the intermediate transfer belt 44 and the secondary transfer roll 46A. In this case, the density adjustment pattern is not transferred to the transfer roll 46A. Thus, it is necessary to control the transfer bias in the direction in which the toner is held on the intermediate transfer belt 44.

  As shown in FIG. 9, in step 100, it is determined whether or not the continuous paper P is set. If the determination is negative, the process proceeds to step 400. If the determination is affirmative, the process proceeds to step 104. .

  In step 400, automatic conveyance of the continuous paper P is started, and the routine proceeds to step 402. In step 402, it is determined whether or not the continuous paper P is supplied to the transfer position. This determination is made based on, for example, a detection result of a paper detection sensor or the like. If the determination is negative, the process proceeds to step 404. If the determination is affirmative, the process proceeds to step 104. In step 104, “first density control” is performed.

  In step 404, “first density control” is performed. Next, in step 406, the continuous paper setting is completed, and the routine proceeds to step 106. In step 106, an image forming process is started. The subsequent procedure is the same as the image forming process shown in FIG.

  The device configurations described in the above embodiments are merely examples, and it goes without saying that the configurations may be changed without departing from the gist of the present invention. For example, the order of the steps in the flowchart may be changed. Needless to say, the procedure executed by software may be realized by hardware.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Paper feeding apparatus 14 Image forming part 16 Housing apparatus 18 Control apparatus 20 Paper feeding roll 22 Housing roll 24 Image forming apparatus 26 Intermediate transfer apparatus 28 Fixing apparatus 28A Heating rotary body 28B Pressure rotating body 30 Photosensitive drum 32 charging device 32A charging roll 34 exposure device 36 developing device 38 primary transfer device 38A primary transfer roll 40 cleaning device 40A blade 42 toner cartridge 44 intermediate transfer belt 46 secondary transfer device 46A secondary transfer roll 48 density sensor 51 release paper 52 adhesive Layer 53 Surface base material 60 Toner density sensor 62 Toner supply motor 64 Pixel counter 66 Moving mechanism motor P Continuous paper

Claims (5)

Image forming means for transferring the toner image on the image carrier to continuous paper to form an image;
Prior to image formation on continuous paper, the image forming means is controlled to form a density-adjusted toner image on the image carrier with the image carrier and continuous paper being separated from each other, and the density-adjusted toner image density is adjusted. Control means for performing first density control based on the second density control different from the first density control when the image carrier and the continuous paper are in contact with each other during image formation on the continuous paper;
An image forming apparatus.   In the second density control, the toner consumption amount is predicted based on the image information, the toner supply amount to the developing device is controlled based on the predicted toner consumption amount, and the developer in the developing device The image forming apparatus according to claim 1, wherein the image forming apparatus is at least one of density control that detects a ratio of toner to a carrier and controls a toner supply amount to a developing device based on the obtained detection result.   The image forming apparatus according to claim 2, wherein the predicted toner consumption is corrected according to an environmental condition including at least one of temperature and humidity.   The image forming apparatus according to claim 2, wherein the predicted toner consumption is corrected according to a paper width of continuous paper. 5. The first density control according to claim 1, wherein the control unit performs the first density control in a state where there is no continuous paper at the transfer position before image formation on the continuous paper and before supply of the continuous paper to the transfer position. The image forming apparatus according to any one of the above.

Images