JP2010134119A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of executing printing processing in which priority is given to image quality, so as to keep the image quality at a constant level and printing processing in which priority is given to productivity as well and to provide an image forming method. <P>SOLUTION: The image forming apparatus includes a calculation means 401 calculating the size of an image to be formed and an adjustment means 402 adjusting a position on an image holder 6 where a latent image forming means 7 starts the formation of a latent image according to the image, on the basis of the size of the image calculated by the calculation means 401. Thus, printing processing in which priority is given to image quality, so as to keep the image quality at a constant level or printing processing in which priority is given to productivity can be executed according to the size of the image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method.

  2. Description of the Related Art As image forming apparatuses such as copying machines and printers, apparatuses that sequentially perform processes such as charging, exposure, development, transfer, and cleaning using a photoreceptor are widely known. In such an image forming apparatus, a correction operation is performed in order to keep the image quality at a certain level. An image forming apparatus capable of forming a color image is required to have a higher level of image quality and stability because changes in image quality such as color and density are easily understood on a sheet.

In Patent Document 1, a correction patch is created at the timing when the home position sensor is detected, and the density of the correction patch is detected.
JP 2007-148248 A

  The present invention provides an image forming apparatus and an image forming method capable of executing print processing with priority on image quality so as to keep the image quality at a constant level and capable of executing print processing with priority on productivity.

  The image forming apparatus according to claim 1, wherein the latent image forming unit is a latent image when the size of the image calculated by the calculating unit is a first size. The image holding body in which the latent image forming means starts forming the latent image when the position on the image holding body where the image formation starts is always adjusted to a specific position and the image size is the second size. And adjusting means for adjusting the upper position to an arbitrary position.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the first size is an integral multiple of a circumference of the image carrier, and the second size is the It is a non-integer multiple of the circumference of the image carrier.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image carrier is predetermined as a position where the latent image forming unit starts forming a latent image. A plurality of different positions, and when the adjustment unit forms a plurality of images included in one image forming process, the adjustment unit is arranged at any one of the plurality of predetermined different positions. The latent image forming unit adjusts a position at which formation of latent images corresponding to the plurality of images is started.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the adjustment unit is configured to form the latent image forming unit based on an operation mode of the image forming apparatus. Adjusts the position on the image holding body at which formation of a latent image starts.

  The image forming apparatus according to claim 5 is the image forming apparatus according to claim 4, wherein the operation mode prioritizes an image quality priority mode that prioritizes image quality of an image to be formed, and productivity of an image to be formed. The adjustment means adjusts the position where the latent image forming means starts forming the latent image in the image quality priority mode, and the latent image forming means in the productivity priority mode. Does not adjust the position where the latent image starts to be formed.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, the image forming apparatus further comprises accepting means for accepting an operation mode of the image forming apparatus from a user, and the adjusting means is the accepting means. The latent image forming means adjusts the position on the image holding body where the latent image forming unit starts forming a latent image based on the operation mode received by the image forming apparatus.

  According to a seventh aspect of the present invention, there is provided a calculation step of calculating a size of an image to be formed, and the latent image forming means is a latent image when the size of the image calculated by the calculation step is a first size. The image holding body in which the latent image forming means starts forming the latent image when the position on the image holding body where the image formation starts is always adjusted to a specific position and the image size is the second size. And an adjusting step for adjusting the upper position to an arbitrary position.

  According to the first aspect of the present invention, it is possible to execute a printing process that prioritizes image quality or a printing process that prioritizes productivity so as to keep the image quality at a certain level according to the size of the image.

  According to the second aspect of the invention, when the size of the image is an integral multiple of the circumference of the image carrier, the printing process is performed with priority on the image quality, and the size of the image is the circumference of the image carrier. If the length is a non-integer multiple, the printing process can be performed with priority on productivity.

  According to the third aspect of the present invention, the image quality of a plurality of images included in one image forming process can be maintained at a certain level.

  According to the fourth aspect of the present invention, based on the image size and the operation mode, the print process giving priority to the image quality or the print process giving priority to productivity is executed so as to keep the image quality at a certain level. it can.

  According to the invention described in claim 5, regardless of the size of the image, in the image quality priority mode, it is possible to execute print processing with priority on image quality, and in the productivity priority mode, priority is given to productivity. Can be executed.

  According to the sixth aspect of the present invention, it is possible to execute a printing process corresponding to a matter that the user wants to prioritize.

  According to the seventh aspect of the present invention, it is possible to execute a printing process that prioritizes image quality or a printing process that prioritizes productivity so as to keep the image quality at a certain level according to the size of the image.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing an example of an image forming apparatus to which the present invention is applied.
The image forming apparatus 1 includes an image forming unit 20 that forms an image based on image data by an electrophotographic method, and a paper feeding unit 30 that supplies a recording material to the image forming unit 20.
The paper feed unit 30 supplies the image forming unit 20 with a recording material of the size and type specified by the image data received by the image forming apparatus 1.

The image forming unit 20 includes C (cyan), M (magenta), Y (yellow), and K (black) image forming units 5C, 5M, 5Y, and 5K, an intermediate transfer member 10, and a secondary transfer unit. 11 and a fixing unit 12.
Each image forming unit includes photosensitive drums (image carriers) 6C, 6M, 6Y, and 6K, latent image forming units 7C, 7M, 7Y, and 7K, developing devices 8C, 8M, 8Y, and 8K, and a cleaner. 9C, 9M, 9Y, 9K.
In each image forming unit, the latent image forming units 7C, 7M, 7Y, and 7K optically scan with a laser scan or an LED head, and the latent images are formed on the surfaces of the photosensitive drums 6C, 6M, 6Y, and 6K based on the image data. Form. The latent images formed on the photosensitive drums 6C, 6M, 6Y, and 6K are developed as toner images of C, M, Y, and K colors by the developing devices 8C, 8M, 8Y, and 8K, respectively. The cleaners 9C, 9M, 9Y, and 9K remove toner remaining on the surfaces of the photosensitive drums 6C, 6M, 6Y, and 6K after the toner images are transferred to the intermediate transfer body 10.
Thereafter, unless particularly distinguished, the image forming units 5C, 5M, 5Y and 5K are the image forming unit 5, the photosensitive drums 6C, 6M, 6Y and 6K are the photosensitive drum 6, and the latent image forming means 7C. 7M, 7Y, and 7K are referred to as a latent image forming unit 7, the developing devices 8C, 8M, 8Y, and 8K are referred to as a developing device 8, and the cleaners 9C, 9M, 9Y, and 9K are referred to as a cleaner 9.

The intermediate transfer member 10 rotates while being in contact with the photosensitive drum 6, whereby the developed toner image is transferred onto the photosensitive drum 6.
The toner image transferred onto the intermediate transfer member 10 is sent to the transfer position of the secondary transfer unit 11 by the rotation of the intermediate transfer member 10.
The paper feeding unit 30 feeds the recording material so that the recording material reaches the secondary transfer unit 11 at the timing when the toner image on the intermediate transfer body 10 reaches the transfer position of the secondary transfer unit 11. The secondary transfer unit 11 transfers the toner image on the intermediate transfer body 10 to the recording material conveyed from the paper supply unit 30. The fixing unit 12 fixes the toner image on the recording material to the sheet. The recording material on which the toner image is fixed by the fixing unit 12 is sequentially discharged to the paper discharge port 13.

Next, the system configuration of the image forming apparatus will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of a system configuration of the image forming apparatus 1.
The image forming apparatus 1 includes an operation unit 50, an image forming unit 20, a paper feeding unit 30, and a control unit 40.
Since the configuration of the image forming unit 20 and the paper feeding unit 30 have been described with reference to FIG. 1, the control unit 40 will be described here.
The control unit 40 is connected to the external device 100, each component of the image forming unit 20, and the paper feeding unit 30. When the control unit 40 receives a request to output image data from the external device 100, the control unit 40 and the photosensitive drum 6 and the photosensitive drum 6 so that the latent image forming unit 7 forms a latent image on the photosensitive drum 6 based on the image data. The latent image forming means 7 is controlled. At this time, the control unit 40 adjusts the position on the photosensitive drum 6 where the latent image forming unit 7 starts the formation of the latent image based on the size of the image to be formed (hereinafter abbreviated as image size).
Here, the external device 100 is a device that requests the image forming apparatus 1 to output image data, and specifically, is a personal computer, a facsimile, a scanner, or the like that requests image output. In addition, the image forming apparatus 1 includes an image reading device (not shown) that reads an image from a sheet on which an image to be output is formed. The image forming device 1 reads not only the image data received from the external device 100 but also the image reading device. The photosensitive drum 6 and the latent image forming unit 7 can be controlled based on the image data.

Next, the control unit 40 controls the developing device 8 and the photosensitive drum 6 in order to attract and develop toner on the latent image formed on the photosensitive drum 6. Then, the control unit 40 controls the photosensitive drum 6 and the intermediate transfer body 10 so that the toner image on the photosensitive drum 6 is transferred to the intermediate transfer body 10. The control unit 40 controls the intermediate transfer member 10 to send the toner image transferred onto the intermediate transfer member 10 to the transfer position of the secondary transfer unit 11. The controller 40 receives the recording material fed from the paper feed unit 30 at the transfer position of the secondary transfer unit 11 at the timing when the toner image on the intermediate transfer body 10 reaches the transfer position of the secondary transfer unit 11. The sheet feeding unit 30 is controlled to do so. The control unit 40 controls the secondary transfer unit 11 and the fixing unit 12 so that an image is appropriately formed on the recording material.
In addition, the control unit 40 receives the operation mode of the image forming apparatus 1 input by the user in the operation unit 50 and controls each configuration of the image forming unit 20 based on the operation mode.

Next, the control unit 40 will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a hardware configuration of the control unit 40.
The control unit 40 includes an input / output unit 44 that inputs and outputs signals, a ROM 43 that stores a program (details will be described later) for adjusting the position where the latent image forming unit 7 starts forming a latent image, and the ROM 43. A central processing unit (CPU) 41 that reads and executes a stored program and a RAM 42 that stores temporary data used when the program is executed.
Moreover, the calculation means 401 and the adjustment means 402 shown in FIG. 4 are comprised by the calculation by CPU41 of the program stored in ROM43.

FIG. 4 is an example of a functional block diagram of the control unit 40 realized by the cooperation of the hardware such as the CPU 41 described above and the software stored in the ROM 43.
The control unit 40 includes a calculation unit 401, an adjustment unit 402, and a reception unit 403.
The calculation unit 401 is connected to the external device 100, the adjustment unit 402, and the reception unit 403. The calculation unit 401 receives image data from the external device 100, and compares the circumference of the photosensitive drum 6 with the length in the conveyance direction of the image included in the image data to calculate the image size. The image size is expressed by how many times the circumferential length of the photosensitive drum 6 corresponds to the length of the image in the conveyance direction. Hereinafter, the fact that the image size is n times the circumferential length of the photosensitive drum 6 is referred to as an n-drum interval. The calculation unit 401 outputs the calculated image size to the adjustment unit 402.

The accepting unit 403 is connected to the operation unit 50 and the adjusting unit 402. The accepting unit 403 accepts the operation mode of the image forming apparatus 1 input by the user to the operation unit 50. Here, the operation mode is whether the image forming apparatus 1 prioritizes the image quality of an image to be formed (hereinafter referred to as an image quality priority mode) or productivity (hereinafter referred to as a productivity priority mode). Or, it is determined whether to follow a predetermined setting (hereinafter referred to as a normal mode).
The accepting unit 403 outputs the accepted operation mode to the adjusting unit 402.

  The adjusting unit 402 is connected to the calculating unit 401, the receiving unit 403, the photosensitive drum 6, and the latent image forming unit 7. The adjustment unit 402 receives the image size from the calculation unit 401. In the image forming apparatus 1 of the present invention, in order to keep the image quality of the formed image at a certain level, it is desirable that the position on the photosensitive drum 6 where the formation of the latent image is started is the same as much as possible. It is. Therefore, when the image size is an integer multiple drum interval, the adjusting unit 402 determines that the position on the photosensitive drum 6 where the latent image forming unit 7 starts forming the latent image is a specific position on the photosensitive drum 6. Thus, the photosensitive drum 6 and the latent image forming means 7 are adjusted. On the other hand, when the image size is a non-integer multiple drum interval, the adjusting unit 402 does not adjust the position on the photosensitive drum 6 where the latent image forming unit 7 starts to form a latent image.

Here, the relationship between the image size and the case where the adjusting unit 402 adjusts the position on the photosensitive drum 6 where the latent image forming unit 7 starts to form a latent image will be described with reference to FIGS.
FIG. 5 is an enlarged view of an example of the photosensitive drum 6 used in the image forming apparatus 1 of the present embodiment. On the photosensitive drum 6, four positions A, B, C, and D are determined as positions at which formation of a latent image can be started. The positions on the photosensitive drum 6 where the formation of the latent image can be started are not fixed at four places as shown in FIG. 5, but may be two places or three places. Alternatively, a photosensitive drum that can start formation of a latent image from any position on the photosensitive drum may be used as the photosensitive drum 6.

FIG. 6 shows a position on the photosensitive drum 6 where the latent image forming unit 7 starts forming a latent image and a toner image transferred onto the intermediate transfer member 10 when the image size is an integer multiple drum interval. This shows the relationship.
FIG. 6A shows the position on the photosensitive drum 6 at which the formation of the latent image is started and the intermediate transfer body when the single-sided printing (A) and the double-sided printing (B) are performed at an image size of 1 drum interval. 10 is a diagram illustrating an example of a relationship between toner images transferred onto the image. In FIG. 6, the intermediate transfer member 10 is developed in the rotation direction, and a rectangle arranged on the intermediate transfer member 10 indicates a toner image, and the number described in the rectangle indicates the page number of the image to be formed. Show. Further, the inverted triangle shown above the intermediate transfer member 10 represents the position on the photosensitive drum 6 shown in FIG. 5, and the position where the formation of the latent image corresponding to each toner image is displayed in alphabetical letters. Yes.
When the image size is 1 drum interval, the formation of the latent image is started from A of the photosensitive drum 6. When single-sided printing is performed, the formation of the latent image can be started from A for any page. FIG. 6 shows the case where the position where the latent image forming means 7 starts forming the latent image is A, but the same applies to the case of B, C, and D.
Similarly, in the case of double-sided printing, when the formation of the latent image is started from A of the photosensitive drum 6, the formation of the latent image is started from A for both the front and back surfaces (indicated by hatching in the drawing). Can do.

FIG. 6B is a diagram illustrating a case where the image size is an interval of 2 drums. When the image size is 2 drum intervals, as in the case of 1 drum interval, latent image formation can be started from A for any page regardless of single-sided printing (A) or double-sided printing (B). it can.
In addition to the case of the 1-drum interval and the 2-drum interval shown in this embodiment, when the image size is an integer multiple drum interval, the position on the photosensitive drum 6 where the formation of the latent image of each page is started. Can be in the same position.
As described above, in the image forming apparatus 1 of the present invention, the position on the photosensitive drum 6 where the formation of the latent image is started is the same as much as possible in order to keep the image quality of the formed image at a certain level. It is desirable that Therefore, in the case of the integer multiple drum interval, the position on the photosensitive drum 6 where the formation of the latent image is started can be made the same position, so that the image quality of the formed image can be kept at a constant level.

Next, the case where the image size is a non-integer multiple drum interval will be described with reference to FIG. FIG. 7 shows a position on the photosensitive drum 6 where the latent image forming means 7 starts forming a latent image and a toner image transferred onto the intermediate transfer body 10 when the image size is a non-integer multiple drum interval. This shows the relationship.
FIG. 7A shows the position on the photosensitive drum 6 where the latent image is formed and the intermediate position when single-sided printing (A) and double-sided printing (B) are performed at an image size of 1.25 drum intervals. 3 is a diagram illustrating an example of a relationship between toner images transferred onto a transfer body 10. FIG.
When the image size is 1.25 drum intervals, when the formation of the latent image is started from A, the formation of the latent image is finished before B. Therefore, if the image quality of the image to be formed is kept at a certain level and the latent image of the next image is to be formed from A, the latent image forming means 7 rotates the photosensitive drum 6 so that A is the latent image. It must wait to start forming the latent image until it reaches a position where it can be formed. Then, the toner image transferred onto the intermediate transfer member 10 is as shown in (a), and the number of recording materials (hereinafter referred to as productivity) that the image forming apparatus 1 can form an image within a predetermined time decreases. To do. Therefore, in the case of the non-integer multiple drum interval, the adjusting unit 402 gives priority to productivity over the image quality, and does not adjust the position on the photosensitive drum 6 where the latent image forming unit 7 starts the latent image formation. Then, the formation of the latent image for each image is started not only from A but also from other positions such as B, C, and D as shown in (b).
Also in the case of double-sided printing, if the image quality of the image to be formed is kept at a certain level and the latent image of the next image is to be formed from A, the toner image will be arranged as shown in (c). Sexuality decreases. Therefore, the adjusting unit 402 does not adjust the position on the photosensitive drum 6 where the latent image forming unit 7 starts forming the latent image. Then, the formation of the latent image for each image is started not only from A but also from other positions such as B, C, and D as shown in (d).

FIG. 7B is a diagram illustrating a case where the image size is 2.5 drum intervals. When the image size is 2.5 drum intervals, the latent image forming means 7 starts forming the latent image from A, and if the formation of the latent image of each image is started from A, the single-sided printing (A) and In both cases of double-sided printing (B), the productivity is reduced as in the case described with an interval of 1.25 drums. Therefore, the adjusting unit 402 does not adjust the position on the photosensitive drum 6 where the latent image forming unit 7 starts forming the latent image. Then, the formation of the latent image for each image is started not only from A but also from C.
As is apparent from FIG. 7, when the image size is a non-integer multiple drum interval, the adjusting unit 402 does not adjust the position on the photosensitive drum 6 where the latent image forming unit 7 starts forming the latent image. Therefore, the image forming apparatus 1 executes a printing process giving priority to productivity.

Next, with reference to FIG. 8, a description will be given of a case where the printing process or setup with an image size of a non-integer multiple drum interval is performed by interruption during the printing process with an image size of an integral multiple drum interval. FIG. 8 shows the formation of a latent image when a printing process (indicated by hatching in the drawing) with an image size of a non-integer multiple drum interval is interrupted during a printing process with an image size of an integer multiple drum interval. 2 is a diagram illustrating an example of a relationship between a position on a photosensitive drum 6 to be started and a toner image transferred onto an intermediate transfer body 10. FIG. The formation of the latent image of image 1 whose image size is an integer multiple drum interval was started from A, and after the formation of the latent image of image 2, the formation of a latent image of an image whose image size was a non-integer multiple drum interval was started. And
When the present invention is not applied, the position at which the latent image forming unit 7 starts forming the latent image is not adjusted regardless of whether the image size is an integer multiple drum interval or a non-integer multiple interval. Therefore, as shown in FIG. 8 (1), the latent image forming unit 7 starts forming the latent images of the image 1 and the image 2 from A for the images of the integer multiple drum intervals, but from the image 3 and the subsequent images from the C Start forming. Therefore, the image forming apparatus 1 cannot maintain the image quality of the image to be formed at a certain level.
On the other hand, when the present invention is applied, the latent image forming unit 7 starts forming latent images of the image 1 and the image 2 from A. Subsequently, the latent image forming unit 7 forms latent images of the image 1A and the image 2A. Here, since the image sizes of the image 1A and the image 2A are non-integer multiples, the adjustment unit 402 does not adjust the position where the latent image formation is started. Therefore, the latent image forming unit 7 starts forming the latent image of the image 1A from A and starts forming the latent image of the image 2A from B.
After completing the formation of the latent images of the image 1A and the image 2A, the latent image forming unit 7 starts forming the latent image of the image 3. Here, since the image size of the image 3 is an integer multiple drum interval, the adjusting unit 402 adjusts the photosensitive drum 6 and the latent image forming unit 7 so that the position where the latent image formation is started is A. . Therefore, as shown in FIGS. 8B and 8A, the latent image forming unit 7 forms a latent image of image 3 from A. Then, the latent image forming unit 7 can start the formation of the latent image from A for the images of the integer multiple drum intervals after the image 3. Therefore, the image forming apparatus 1 can maintain the image quality of the image to be formed at a certain level.
8B, 8B, and 8D show that the adjustment unit 402 forms the latent image when the position where the latent image formation of the image 1 is started is the B, C, and D positions. It is the figure which showed a mode that the position to start is adjusted. The processing executed by the adjusting unit 402 is not different from that in the case of (A), and the description thereof is omitted.

Next, with reference to FIG. 9 and FIG. 10, a description will be given of a case where another print process or set-up with an image size of a non-integer multiple drum interval is performed by an interrupt during execution of a print process with a non-integer multiple drum interval. To do. FIG. 9 shows a case where a latent image is printed when another print process (indicated by hatching in the figure) with an image size of a non-integer multiple drum interval is interrupted during execution of a print process with an image size of 1.25 drum intervals. 4 is a diagram illustrating an example of a relationship between a position on the photosensitive drum 6 where image formation is started and a toner image transferred onto the intermediate transfer body 10. FIG.
In FIG. 9A, if the position at which the latent image forming unit 7 starts forming the latent image of the image 1 is A, the image size of the image 2 is a non-integer multiple drum interval. The position for starting the formation of the latent image is not adjusted. Therefore, the latent image forming unit 7 starts forming a latent image of the image 2 from B. Next, the latent image forming unit 7 starts forming a latent image of the image 1A. Since the image size of the image 1A is also a non-integer multiple drum interval, the adjusting unit 402 does not adjust the position where the formation of the latent image of the image 1A is started. Therefore, the latent image forming unit 7 starts forming a latent image of the image 1A from C. Similarly, since the image size of the remaining images is a non-integer multiple, the adjusting unit 402 does not adjust the position where the latent image formation is started. Therefore, the image forming apparatus 1 executes image forming processing giving priority to productivity.
FIGS. 9B to 9D show positions where the adjustment unit 402 starts forming the latent image when the position where the latent image of image 1 is started is the B, C, and D positions. It is the figure which showed a mode that it adjusts. The processing executed by the adjusting unit 402 is not different from that in the case of (A), and the description thereof is omitted.

FIG. 10 shows a case where a latent image is printed when another printing process (indicated by hatching in the figure) with an image size of a non-integer multiple drum interval is interrupted during the printing process with an image size of 2.5 drum intervals. 4 is a diagram illustrating an example of a relationship between a position on the photosensitive drum 6 where image formation is started and a toner image transferred onto the intermediate transfer body 10. FIG.
In FIG. 10A, when the position at which the latent image forming unit 7 starts forming the latent image of the image 1 is A, the image size of the image 2 is a non-integer multiple drum interval. The position at which formation of the second latent image starts is not adjusted. Therefore, the latent image forming unit 7 starts forming a latent image of the image 2 from C. Next, the latent image forming unit 7 starts forming a latent image of the image 1A. Since the image size of the image 1A is also a non-integer multiple drum interval, the adjusting unit 402 does not adjust the position where the formation of the latent image of the image 1A is started. Therefore, the latent image forming unit 7 starts forming a latent image of the image 1A from A. Similarly, since the image size of the remaining images is a non-integer multiple, the adjustment unit 402 does not adjust the position where the latent image formation is started. Therefore, the image forming apparatus 1 executes image forming processing giving priority to productivity.
10B to 10D show the photosensitive drum 6 in which the latent image formation is started when the positions where the latent image formation of the image 1 is started are the positions B, C, and D. 3 is a diagram illustrating an example of a relationship between an upper position and a toner image transferred onto an intermediate transfer body 10. FIG. The processing executed by the adjusting unit 402 is not different from that in the case of (A), and the description thereof is omitted.

  Here, the adjusting means 402 will be further described with reference to FIG. The adjustment unit 402 inputs the operation mode of the image forming apparatus 1 from the reception unit 403. The adjusting unit 402 adjusts the position where the latent image formation is started based on the operation mode and the image size input from the receiving unit 403.

Here, with reference to FIG. 11, it will be described whether or not the adjustment unit 402 adjusts the position where the latent image formation is started based on the image size and the operation mode. FIG. 11 is an example of a table that determines whether or not the adjustment unit 402 adjusts the position where the latent image formation is started based on the image size and the operation mode.
First, the case where the image size is an integer multiple drum interval will be described. When the image size is an integer multiple drum interval and the normal mode or the image quality priority mode is input from the reception unit 403, the adjustment unit 402 determines the position on the photosensitive drum 6 where the latent image forming unit 7 starts the formation of the latent image. adjust. When the image size is an integer multiple drum interval and the productivity priority mode is input from the accepting unit 403, the adjusting unit 402 does not adjust the position where the latent image forming unit 7 starts forming the latent image.
Next, the case where the image size is a non-integer multiple drum interval will be described. When the image size is a non-integer multiple drum interval and the normal mode or the productivity priority mode is input from the accepting unit 403, the adjusting unit 402 does not adjust the position where the latent image forming unit 7 starts forming the latent image. When the image size is a non-integer multiple drum interval and the image quality priority mode is input from the accepting unit 403, the adjusting unit 402 adjusts the position on the photosensitive drum 6 where the latent image forming unit 7 starts forming the latent image. .

The above relationship will be described with reference to FIG. FIG. 12 shows an example of the relationship between the position on the photosensitive drum 6 where the formation of the latent image starts and the toner image arranged on the intermediate transfer body 10 depending on the difference in image size and operation mode. is there.
FIG. 12A shows a toner image arranged on the intermediate transfer body 10 and a position on the photosensitive drum 6 where formation of a latent image is started due to a difference in each operation mode when the image size is an integral multiple. An example of the relationship is shown.
In FIG. 12A, description will be made by taking as an example a case where printing processing with an image size of a non-integer multiple drum interval is performed by interruption while an image with an image size of an integer multiple drum interval is being printed. In any operation mode, it is assumed that the latent image forming unit 7 starts forming the latent image of the image 1 from A.
When the operation mode is the normal mode (A) and the image quality priority mode (C), the adjustment unit 402 starts the formation of the latent image of the image 3 from A as described with reference to FIG. Then, the latent image forming means 7 and the photosensitive drum 6 are adjusted.
However, when the operation mode is the productivity priority mode (B), the adjustment unit 402 does not adjust the position at which the latent image forming unit 7 starts forming the latent image. The image formation is started from C, and the formation of latent images is similarly started from C for the images after image 3.

FIG. 12B shows a position on the photosensitive drum 6 where the latent image formation is started due to a difference in each operation mode and a toner arranged on the intermediate transfer body 10 when the image size is a non-integer multiple. An example of a relationship with an image is shown.
FIG. 12 illustrates an example in which another print process of an image having an image size of a non-integer multiple drum interval is performed by interruption while an image having an image size of a non-integer multiple drum interval is being printed. . In any operation mode, it is assumed that the latent image forming unit 7 starts forming the latent image of the image 1 from A.
When the operation mode is the normal mode (A) and the productivity priority mode (B), the adjusting unit 402 does not adjust the position at which the latent image forming unit 7 starts forming the latent image. Therefore, the latent image forming unit 7 forms a latent image of each image so that the toner images are continuously arranged.
Next, a case where the operation mode is the image quality priority mode will be described. In FIGS. 12B and 12C, it is assumed that the image quality priority mode is selected for the printing process including the image 1 and the normal mode is selected for the printing process including the image 1A. Then, since the operation mode is the image quality priority mode for the printing process including the image 1, the adjustment unit 402 adjusts the position where the latent image formation is started to be a specific position. Accordingly, the latent image forming unit 7 starts the formation of the latent image of the image 2 from A, and also starts the formation of the latent image of the image 3 that comes after the image 2A that has been subjected to the printing process by interruption. The latent image forming unit 7 also starts forming latent images from A for the images subsequent to the image 4. On the other hand, since the operation mode of the image 1A and the image 2A is the normal mode, the adjusting unit 402 does not adjust the position where the latent image forming unit 7 forms a latent image.
With this configuration, even if the image size is a non-integer multiple drum interval, if the operation mode is the image quality priority mode, the image forming apparatus 1 performs image formation processing that prioritizes image quality so as to keep the image quality of the image to be formed at a certain level. Can be executed. Further, even if the image size is an integer multiple drum interval, if the operation mode is the productivity priority mode, the image forming apparatus 1 can execute the image forming process giving priority to the productivity.

Next, processing performed by the image forming apparatus that has input image data will be described with reference to FIG. FIG. 13 is a flowchart illustrating an example of processing executed by the image forming apparatus 1 that has input image data.
The control unit 40 first confirms the image size included in the image data, and determines whether or not the image size is a printing process with an integer multiple drum interval (step S10). When the image size is a printing process with an integer multiple drum interval (step S10 / YES), the control unit 40 checks whether or not the operation mode is the productivity priority mode (step S11). In the productivity priority mode (step S11 / YES), the control unit 40 does not adjust the position where the latent image formation is started, and the latent image forming unit 7 forms the latent image (step S12). The image forming unit 20 develops the latent image, transfers it to the recording material via the intermediate transfer body 10, and executes an image forming process based on the image data (step S13). After the image forming unit 20 executes the image forming process, the control unit 40 checks whether or not all the image forming processes included in the image data have been completed (step S14). When the formation processing of all the images included in the image data has not been completed (step S14 / NO), the control unit 40 and the image forming unit 20 perform steps from step 12 until the formation of the image included in the image data is completed. The process up to 14 is repeated. When the image forming process included in the image data ends (step S14 / YES), the image forming apparatus 1 ends the image forming process.

  When the image size is a printing process with an integer multiple drum interval (step S10 / YES) and is not in the productivity priority mode (step S11 / NO), the control unit 40 starts from a specific position on the photosensitive drum 6. The photosensitive drum 6 and the latent image forming means 7 are controlled so as to form a latent image. First, the control unit 40 adjusts the start position of the latent image based on the first image included in the image data (step S15). Then, the position on the photosensitive drum where the first latent image is arranged is stored in the RAM 42 (step S16). The image forming unit 20 performs an image forming process using the toner image formed on the photosensitive drum 6 (step S17). Next, the control unit 40 adjusts the photosensitive drum 6 and the latent image forming unit 7 so as to start forming a latent image from the position stored in step S16 (step S18). Then, the image forming unit 20 executes an image forming process (step S19). The control unit 40 checks whether or not the image forming process has been completed for all the images included in the image data (step S20). When the image forming process has not been completed for all the images included in the image data (step S20 / NO), the control unit 40 and the image forming unit 20 start from step S18 until the formation of the image included in the image data is completed. Step S20 is repeated. When the image forming process included in the image data ends (step S20 / YES), the image forming apparatus 1 ends the image forming process.

  When the image size included in the image data input by the image forming apparatus 1 is not an integer multiple drum interval (step S10 / NO), the control unit 40 confirms whether or not the operation mode is the image quality priority mode (step S30). If the operation mode is not the image quality priority mode (NO in step S30), the latent image forming unit 7 forms a latent image without adjusting the position where the latent image formation is started (step S31). The image forming unit 20 executes an image forming process (step S32). The control unit 40 confirms whether or not the processing for forming the image included in the image data has been completed (step S33). If the image forming process has not been completed for all the images included in the image data (step S33 / NO), the control unit 40 and the image forming unit 20 start from step S31 until the formation of the image included in the image data is completed. Step S33 is repeated. When all the images included in the image data are formed (step S33 / YES), the image forming apparatus 1 ends the image forming process.

When the image size is a printing process with a non-integer multiple drum interval (step S10 / NO) and is not in the image quality priority mode (step S30 / YES), the control unit 40 starts from a specific position on the photosensitive drum 6. The photosensitive drum 6 and the latent image forming means 7 are controlled so as to form a latent image. First, the control unit 40 adjusts the start position of the latent image based on the first image included in the image data (step S34). The position on the photosensitive drum 6 where the first latent image is arranged is stored in the RAM 42 (step S35). The image forming unit 20 performs an image forming process (step S36). Next, the control unit 40 adjusts the photosensitive drum 6 and the latent image forming unit 7 so as to start forming a latent image from the position stored in step S16 (step S37). Then, the image forming unit 20 executes an image forming process (step S38). The control unit 40 confirms whether or not the image forming process has been completed for all images included in the image data (step S39). When the image forming process has not been completed for all the images included in the image data (step S39 / NO), the control unit 40 and the image forming unit 20 start from step S37 until the formation of the image included in the image data is completed. Step S39 is repeated. When all the images included in the image data are formed (step S39 / YES), the image forming apparatus 1 ends the image forming process.
The CPU that executes the process of step S10 corresponds to the calculation unit 401. Further, the CPU that executes the processes of step S11, step S12, step S15, step S16, step S18, step S30, step S31, step S34, step S35, and step S37 corresponds to the adjusting unit 402.

As is apparent from the above description, according to the present embodiment, the image forming apparatus 1 gives priority to print processing or productivity that prioritizes image quality so as to keep the image quality at a certain level according to the image size. The selected printing process can be selected and the printing process can be executed. If the operation mode is the image quality priority mode, even if the image size is a non-integer multiple drum interval, it is possible to execute a printing process in which the image quality is prioritized by adjusting the position where the latent image formation is started. On the other hand, if the operation mode is the productivity priority mode, the image forming apparatus 1 can execute print processing with priority on productivity even if the image size is an integer multiple drum interval.
Furthermore, when the user selects the operation mode, the user can obtain an image that realizes the image quality desired by the user.

The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.
For example, in this embodiment, four positions A, B, C, and D are defined on the photosensitive drum 6 as positions where the latent image can be formed as shown in FIG. As shown in FIG. 3, three positions A, B, and C may be determined. FIG. 14 is an enlarged view of the photosensitive drum 6 in which three positions A, B, and C are defined as positions where the formation of the latent image can be started. When the image size is an integer multiple drum interval and a non-integer multiple drum interval by the photosensitive drum 6 shown in FIG. FIG. 15 shows the relationship with the toner image transferred onto the intermediate transfer member 10.
Similarly to the case where four positions are determined as the positions where the latent image formation can be started, when the latent image forming means 7 starts forming the latent image from A, the adjusting means 402 sets the image size to an integral multiple drum interval. In this case, the photosensitive drum 6 and the latent image forming means 7 are adjusted so that latent image formation is started from A for other pages. On the other hand, when the image size is a non-integer multiple drum interval, the adjusting unit 402 does not adjust the position on the photosensitive drum 6 where the latent image formation is started. Therefore, the latent image forming unit 7 forms a latent image so that the toner image is continuously transferred onto the intermediate transfer member 10.

1 is a diagram illustrating an example of an image forming apparatus to which the present invention is applied. 1 is a diagram illustrating an example of a system configuration of an image forming apparatus to which the present invention is applied. It is the figure which showed an example of the hardware constitutions of a control part. It is the figure which showed an example of the functional block diagram of a control part. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image can be started. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image is started when the image size is an integer multiple drum interval. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image is started when the image size is a non-integer multiple drum interval. FIG. 5 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image is started when the present invention is applied to a printing process in which an image size is an integer multiple drum interval. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image is started when the present invention is applied to a printing process in which an image size is an interval of 1.25 drums. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image is started when the present invention is applied to a printing process in which an image size is 2.5 drum intervals. It is a figure showing whether or not the adjusting means adjusts the position where the latent image formation is started based on the image size and the operation mode. 6 shows an example of a relationship between a position on the photosensitive drum 6 where formation of a latent image is started and a toner image arranged on the intermediate transfer member 10 depending on a difference in image size and operation mode. 5 is a flowchart illustrating an example of processing executed by the image forming apparatus. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image can be started. FIG. 6 is a diagram illustrating an example of a position on a photosensitive drum where formation of a latent image is started.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 5C, 5M, 5Y, 5K ... Image forming unit 6C, 6M, 6Y, 6K ... Photosensitive drum (image holding body)
7C, 7M, 7Y, 7K ... latent image forming means 8C, 8M, 8Y, 8K ... developing devices 9C, 9M, 9Y, 9K ... cleaner 10 ... intermediate transfer member 11 ... secondary transfer unit 12 ... fixing unit 13 ... discharge port 20 ... Image forming unit 30 ... Paper feeding unit 40 ... Control unit 41 ... CPU
42 ... RAM
43 ... ROM
44 ... Input / output unit 50 ... Operation unit 100 ... External device 401 ... Calculating unit 402 ... Adjusting unit 403 ... Accepting unit

Claims (7)

Calculating means for calculating the size of the image to be formed;
When the image size calculated by the calculating means is the first size, the latent image forming means adjusts so that the position on the image holding body where the latent image forming means starts forming the latent image is always a specific position. An image forming apparatus comprising: an adjusting unit that adjusts a position on an image holding member at which a latent image forming unit starts forming a latent image to an arbitrary position when the size is a second size.   2. The image according to claim 1, wherein the first size is an integral multiple of the circumference of the image carrier, and the second size is a non-integer multiple of the circumference of the image carrier. Forming equipment. The image carrier has a plurality of predetermined different positions as positions at which the latent image forming unit starts forming a latent image,
In the case where a plurality of images included in one image forming process are formed, the adjusting unit is configured so that the latent image forming unit has the plurality of images at any one of the plurality of predetermined different positions. The image forming apparatus according to claim 1, wherein a position at which formation of a latent image is started is adjusted in accordance with the image forming apparatus.   The adjustment unit adjusts a position on the image carrier where the latent image forming unit starts forming a latent image based on an operation mode of the image forming apparatus. An image forming apparatus according to claim 1. The operation mode includes an image quality priority mode that prioritizes the image quality of the image to be formed, and a productivity priority mode that prioritizes the productivity of the image to be formed,
The adjusting means adjusts a position where the latent image forming means starts forming a latent image in the image quality priority mode, and a position where the latent image forming means starts forming a latent image in the productivity priority mode. The image forming apparatus according to claim 4, wherein the image forming apparatus is not adjusted. A receiving unit for receiving an operation mode of the image forming apparatus from a user;
The adjustment unit adjusts a position on the image holding body at which the latent image forming unit starts forming a latent image based on the operation mode received by the receiving unit. The image forming apparatus according to 5. A calculation step for calculating a size of an image to be formed;
When the size of the image calculated in the calculation step is the first size, the latent image forming unit adjusts the position on the image carrier where the latent image formation starts to be always a specific position, and An image forming method comprising: an adjusting step of adjusting a position on the image holding member at which the latent image forming unit starts forming a latent image to an arbitrary position when the size is the second size.

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