Digital image forming apparatus and method for changing magnification ratio for image according to image data stored in a memory

• US 6,486,971 B1
• Filed: 03/12/1999
• Issued: 11/26/2002
• Est. Priority Date: 03/12/1998
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Kawamoto, Hiroyuki
• Primary Examiner(s): Williams, Kimberly A.
• Application Number:
  US09/266,800
• Time in Patent Office: 1,355 Days
• Field of Search: 358/1.1, 358/1.2, 358/1.9, 358/1.12, 358/1.16, 358/1.18, 358/296, 358/401, 358/444, 358/468
• US Class Current: 358/1.2
• CPC Class Codes: H04N 1/393 Enlarging or reducing

Abstract

An image forming apparatus includes a photoconductor and an image reading device to receive and read a light reflected from an original document carrying image data of an image of the original document and to convert the received light carrying the image data into an analog electrical signal carrying the image data. An analog-to-digital converter converts the analog electrical signal carrying the image data into a digital signal carrying the digital image data and a memory stores the digital image data. An image writing device forms an image according to the digital image data on a surface of the photoconductor with a laser beam modulated according to the digital image data. The image forming apparatus includes a first enlarging/reducing device to change a magnification ratio of the image and is provided upstream of the memory in a direction in which the digital image data is sent. Also included is a second enlarging/reducing device which changes a magnification ratio for the image and is provided downstream of the memory in the direction in which the digital image data is sent. The digital image data processed with the first enlarging/reducing device is stored in the memory and the digital image date reed from the memory is again processed with the second enlarging/reducing device.

Claims

1. An image forming apparatus, comprising:

a photoconductor;

an image reading device to receive and read a light reflected from an original document carrying image data of an image of the original document and to convert the received light carrying the image data into an analog electrical signal carrying the image data;

an analog-to-digital converter to convert the analog electric signal carrying the image data into a digital signal carrying the digital image data;

a memory to store the digital image data;

an image writing device to form an image according to the digital image data on a surface of the photoconductor with a light beam modulated according to the digital image data;

a first enlarging/reducing device, to change a magnification ratio of the image, provided upstream of the memory in a direction in which the digital image data is sent; and

a second enlarging/reducing device to change a magnification ratio for a main scanning direction of the image, provided downstream of the memory in the direction in which the digital image data is sent,

wherein, the digital image data processed with the first enlarging/reducing device is stored in the memory and the digital image data read from the memory is again processed with the second enlarging/reducing device.

2. The image forming apparatus of claim 1, wherein the image reading device comprises a line sensor to read a line of the original document and the memory has a capacity to store digital image data for the line of the original document.

3. An image forming apparatus, comprising:

a photoconductor;

an image reading device to receive and read a light reflected from an original document carrying image data of an image of the original document and to convert the received light carrying the image data into an analog electrical signal carrying the image data;

an analog-to-digital converter to convert the analog electrical signal carrying the image data into a digital signal carrying the digital image data;

a memory to store the digital image data;

an image writing device to form an image according to the digital image data on a surface of the photoconductor with a light beam modulated according to the digital image data;

a first enlarging/reducing device, to change a magnification ratio of the image, provided upstream of the memory in a direction in which the digital image data is sent;

a second enlarging/reducing device to change a magnification ratio for a main scanning direction of the image, provided downstream of the memory in the direction in which the digital image data is sent; and

an image quality enhancing device to process the digital image data to enhance a quality of the image according to the digital image data;

wherein, the digital image data processed with the first enlarging/reducing device and processed with the image quality enhancing device is stored in the memory and the digital image data read from the memory is again processed with the second enlarging/reducing device.

4. The image forming apparatus of claim 3, wherein the image reading device comprises a line sensor to read a line of the original document and the memory has a capacity to store digital image data for the line of the original document.

5. An image forming apparatus, comprising:

a photoconductor;

an image reading device to receive and read a light reflected from an original document carrying image data of an image of the original document and to convert the received light carrying the image data into an analog electrical signal carrying the image data;

an analog-to-digital converter to convert the analog electric signal carrying the image data into a digital signal carrying the digital image data;

a memory to store the digital image data;

an image writing device to form an image according to the digital image data on a surface of the photoconductor with a light beam modulated according to the digital image data;

an enlarging/reducing device to change a magnification ratio for the image;

a first switch device to switch the digital image data to the enlarging/reducing device upstream of the memory in a direction in which the digital image data is sent; and

a second switch device to switch the digital image data read from the memory to the enlarging/reducing device so as to change a magnification ratio for a main scanning direction of the image.

6. The image forming apparatus of claim 5, wherein the image reading device comprises a line sensor to read a line of the original document and the memory has a capacity to store digital image data for the line of the original document.

7. The image forming apparatus of claim 5, wherein a capacity of a FIFO memory used in the second enlarging/reducing device is smaller than a capacity of a FIFO memory used in the first enlarging/reducing device.

8. An image forming apparatus, comprising;

a photoconductor;

image reading means for receiving and reading a light reflected from an original document carrying image data of an image of the original document and for converting the received light carrying the image data into an analog electrical signal carrying the image data;

an analog-to-digital converting means for converting the analog electrical signal carrying the image data into a digital signal carrying the digital image data;

memory means for storing the digital image data;

image writing means for forming an image according to the digital image data on a surface of the photoconductor with a light beam modulated according to the digital image data;

first enlarging/reducing means, for changing a magnification ratio for the image, provided upstream of the memory means in a direction in which the digital image data is sent; and

second enlarging/reducing means, for changing a magnification ratio for a main scanning direction of the image, provided downstream of the memory means in the direction in which the digital image data is sent;

wherein the digital image data processed with the first enlarging/reducing means is stored in the memory means and the digital image data read from the memory means is again processed with the second enlarging/reducing means.

9. The image forming apparatus of claim 8, wherein the image reading means comprises a line sensor to read a line of the original document and the memory means has a capacity to store digital image date for the line of the original document.

10. The image forming apparatus of claim 9, wherein a capacity of a FIFO memory used in the second enlarging/reducing means is smaller than a capacity of a FIFO memory used in the first enlarging/reducing means.

11. An image forming apparatus, comprising:

a photoconductor;

image reading means for receiving and reading a light reflected from an original document carrying image data of an image of the original document and for converting the received light carrying the image data into an analog electrical signal carrying the image data;

analog-to-digital converting means for converting the analog electrical signal carrying the image data into a digital signal carrying the digital image data;

memory means for storing the digital image data;

image writing means for forming an image according to the digital image data on a surface of the photoconductor with light beam modulated according to the digital image data;

first enlarging/reducing means for changing a magnification ratio for the image, said first enlarging/reducing means provided upstream of the memory means in a direction in which the digital image data is sent;

second enlarging/reducing means for changing a magnification ratio for a main scanning direction of the image, said second enlarging/reducing means provided downstream of the memory means in the direction in which the digital image data is sent; and

image quality enhancing means for processing the digital image data to enhance a quality of the image according to the digital image data,

wherein the digital image data processed with the first enlarging/reducing means and processed with the image quality enhancing means is stored in the memory means and the digital image data read from the memory means is again processed with the second enlarging/reducing means.

12. The images forming apparatus of claim 11, wherein the Image reading means comprises a line sensor to read a line of the original document and the memory means has a capacity to store digital image data for the line of the original document.

13. An image forming apparatus, comprising:

a photoconductor;

image reading means for receiving and reading a light reflected from an original document carrying image data of an image of the original document and for converting the received light carrying the image data into an analog electrical signal carrying the image data;

analog-to-digital converting means for converting the analog electrical signal carrying the image data into a digital signal carrying the digital image data;

memory means for storing the digital image data;

image writing means for forming an image according to the digital image data on a surface of the photoconductor with a light beam modulated according to the digital image data;

enlarging/reducing means for changing a magnification ratio for the image;

first switching means for switching the digital image data to the enlarging/reducing means upstream of the memory means in a direction in which the digital image data is sent; and

second switching means for switching the digital image data read from the memory means to the enlarging/reducing means so as to change a magnification ratio for a main scanning direction of the image.

14. The image forming apparatus of claim 13, wherein the image reading means comprises a line sensor to read a line of the original document and the memory means has a capacity to store digital image data for the line of the original document.

15. A method of forming an image, comprising the steps of:

providing a photoconductor;

reading a light reflected from an original document carrying image data of an image of the original document and converting the received light carrying the image data into an analog electrical signal carrying the image data;

converting the analog electrical signal carrying the image data into a digital signal carrying the digital image data;

processing the digital image data to change a magnification ratio for the image according to the digital image data;

storing the processed digital image data in a memory; and

reading the processed digital image data stored in the memory to output the image according to the stored processed image data and processing the stored processed digital image data again to change a magnification ratio for a main scanning direction of the image.

16. The method of claim 15, wherein a light reflected from a line of the original document is read at the reading step.

17. The method of claim 15, further comprising the step of:

processing digital image data to enhance a quality of the image according to the digital image data.

18. The method of claim 17, wherein the image data which is processed to change a magnification ratio of the image according to the image data is stored in the memory after having been processed by the quality enhancing processing step.